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Sleep Matters Get the answers to common sleep conditions

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Foreword Sleep is something that we all do as naturally as breathing and eating, from the time you are formed in utero till the time you die. Yet scientists and doctors understand the physiology of breathing and eating far better than we understand the mysteries of the mind and body during sleep. In the last twenty years however, we are beginning to understand far more about sleep, both the physiology of what happens as we fall asleep, and the pathologies that underlie conditions such as obstructive sleep apnoea and contribute to their morbidity and mortality. Even more importantly, we are much better equipped to diagnose and treat these conditions that affect us mainly when we are asleep, and which affect both the quality of our lives in the day, and our survival.

patient relaxation techniques in cognitive behavioural therapy to treat chronic insomnia (which can help wean the patient off long-term sleeping tablets) to advanced breathing machines to help patient maintain regular breathing, to state-of-the-art robotic surgery to reshape the upper airway to prevent obstructed breathing at night. In this brochure, we hope to introduce to you the more common sleep disorders, along with their signs and symptoms, and what you can do to help yourself. We aim to empower you to understand your conditions and the various treatment options available.

There are two things that can go wrong with your sleep: you can have difficulty falling or staying asleep (insomnia or circadian rhythm disorders), or there can be problems with the quality of the sleep such that there is insufficient oxygen when you sleep or the quality of sleep is so poor that sleep is non-refreshing. The result is that you feel chronically tired, or inappropriately sleepy in the day. The most common condition causing this is obstructive sleep apnea.

The full spectrum of sleep disorders spans many specialties, and in turn even within the individual specialties. Not many people are trained to specifically be able to correctly diagnose and manage sleep problems. At Singapore General Hospital, we are proud to have the oldest and most comprehensive set-up for management of sleep disorders in Singapore. We are also well-supported by laboratories able to do specialised tests for sleep disorders that are offered by few other labs in Singapore. Our dedicated and internationally-qualified doctors strive to achieve the best outcomes for our patients.

The good news is, for both spectrums of sleep disorders, effective and exciting options are now available for treatment. This can be as simple as teaching the

Dr Ong Thun How Director, Sleep Disorders Unit Senior Consultant, Department of Respiratory and Critical Care Medicine Singapore General Hospital


Contents 5

Normal sleep physiology (adults and seniors)


Sleep deprivation


Excessive daytime sleepiness


Sleep-disordered breathing and snoring


Obstructive sleep apnoea


Surgical treatment for snoring and obstructive sleep apnoea (OSA)




Circadian rhythm: Coping with jet lag and shift work


Movement disorders in sleep




Sleepy driving


Common sleep conditions in children


Services available at SingHealth institutions



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Normal sleep physiology (adults and seniors) Sleep is something that we all do as naturally as breathing and eating, from the time you are formed in utero till the time you die. Yet scientists and doctors understand the physiology of breathing and eating far better than we understand the mysteries of the mind and body during sleep. In the last twenty years however, we are beginning to understand far more about sleep, both the physiology of what happens as we fall asleep, and the pathologies that underlie conditions such as obstructive sleep apnoea and its contribution to morbidity and mortality. Sleep is a period of time when the body rests. As you fall asleep, the brain begins to filter out sounds, sights and other sensory input from the surroundings. The muscle tone

gradually relaxes, allowing the body to rest. Scientists divide normal sleep into several stages, using differences in the brain wave patterns and muscle tone to differentiate the stages.

Stages of Sleep Stage N1. This is a ’light’ stage of sleep, where the brain’s sensory input is shutting down but you may still be able to hear and remember sounds and other sensory inputs from the surroundings. It is common to drift in and out of stage N1 sleep before falling deeper into more consolidated stages of sleep. A sleep-deprived person may have episodes or microsleep where brief periods (a few seconds) of N1 sleep are interspersed during wake periods without the person being aware of this. These brief periods of microsleep can be dangerous, for instance in a driver who ’switches off’ without realising it


while driving. Many people who have trouble sleeping are actually drifting in and out of stage one sleep without realising it. Stage N2. As you fall deeper into sleep, the filtering of sensory inputs intensifies. For instance, it will require a louder sound to wake you up from N2 sleep than N1 sleep. The muscle tone in the body drops and the body starts to relax more. When a person’s brain wave activity is tracked as he falls asleep, certain characteristic patterns during this stage of sleep called spindles and K-complexes can be seen. Stage N3. Here you are deeply asleep. It takes more effort to wake you up from N3 sleep. On awakening at this stage you may report that you were having a dream, although the images and memories of dreams in N3 sleep are usually more indistinct. REM (Rapid eye movement) sleep. This is a very interesting stage of sleep, and usually occurs sequentially after you have gone through the first three stages of sleep. In this stage, your


muscle tone is very flaccid, and the voluntary muscles e.g. arms and legs are essentially paralysed. However, there are bursts of eye movements during REM sleep, hence this is called rapid eye movement sleep. In this stage of sleep, both breathing and heart rate become less regular. In people with underlying heart and lung disease the oxygen levels in the body can fall to very low levels. Despite the inactivity seen in the muscles, there is actually increased brain wave activity, and when you wake from REM sleep, you may report very vivid dreams.

How much sleep do you need? An average adult sleeps about seven hours a night. However, there is a wide range of normality with some people needing only 4 hours and others needing up to 10 hours. Some epidemiological studies suggest that people who sleep too little or too much may have more medical problems or a higher mortality rate, although whether this is a cause or effect is debatable.

For most people, a clue to if you are getting enough sleep is whether you find yourself sleeping a lot more over weekends or on holiday when you have less restrictions on when you need to get up. If you are sleeping a lot more whenever you have the chance, and you have a lot of lethargy or daytime sleepiness, chances are you are not sleeping enough to meet your body’s requirements. The quality of sleep also matters – in certain medical conditions and in certain sleep conditions such as obstructive sleep apnoea, there is disruption in this sleep cycle, resulting in poor quality, unrefreshed sleep.

Over the course of a night, most people go through four to five complete cycles of sletep. They drift from stage N1 to N2, to N3 sleep, into REM sleep, and then go back to N1 sleep again. As the night wears on, the length of the REM sleep periods increases, with the longest REM sleep period often occurring just before they wake up.

Most adults need about seven hours of sleep, although the norm can vary.


Sleep deprivation Sleep deprivation is a condition where someone is not getting enough sleep; it can either be chronic or acute. The absolute number of hours of sleep necessary for someone to function properly is not known. Some people can function with full effectiveness with only three to five hours of sleep per night, while others need at least eight hours or more of sleep per night. A chronically sleep-deprived state can cause tiredness, excessive daytime sleepiness, clumsiness and weight gain. It impairs the normal functioning of the brain. It is impossible for humans to go completely without sleep for long periods of time–brief microsleeps cannot be avoided. Total sleep deprivation has been shown to cause death in lab animals.

can automatically shut down, falling into a sleep state that can last from a second to half a minute. You can fall asleep no matter what you are doing. Microsleeps are similar to blackouts and you will not be aware that they are occurring when you are experiencing them.

Effects of sleep deprivation Individuals who are sleep-deprived may not recognise the effects of being so. Small amounts of sleep loss over many

What are microsleeps? Microsleeps occur when someone is significantly sleep-deprived. The brain

The effects of sleep loss are often unrecognised.


nights may result in subtle cognitive loss, which appears to go unrecognised by the individual. More severe sleep deprivation for a week can lead to profound cognitive dysfunction similar to those seen in some stroke patients, which may also appear to go unrecognised by the individual. Sleep deprivation can cause: • Confusion, memory lapses • Depression, irritability, headaches • Eye bags and bloodshot eyes • Increased blood pressure, increased stress hormone level • Increased risk of diabetes, obesity • Decreased immunity • Decreased growth hormones • Increased risk of road traffic accidents • Poor work productivity • Poor quality of life • Sleeping less than four hours a night is associated with higher risk of premature death

Prevention Maintain proper sleep hygiene. Seek medical help if you feel that you are not sleeping well.

Causes Lifestyle You may choose not to sleep to watch a midnight show, talk to friends, play computer or video games. Heavy work commitment and stress may hinder sleep and lead to sleep deprivation. Shift workers may be affected by sleep deprivation. Medical disorders Many medical conditions can lead to sleeplessness and hence sleep deprivation. Chronic pains and aches can lead to disturbed sleep and sleep deprivation. Sleep disorders like obstructive sleep apnoea, narcolepsy, and restless leg syndrome can lead to disruption of normal sleeping pattern and sleep deprivation. Nasal obstruction can result in someone not being able to sleep, therefore being sleep-deprived. Sleep Disorders Unit Singapore General Hospital | Tel: 6321 4377


Excessive daytime sleepiness Excessive daytime sleepiness refers to the inability to stay alert during the major awake period of the day, resulting in you falling asleep at inappropriate times. When sleepiness interferes with daily routines and activities, or reduces your ability to function, it is considered excessive. This is a prevalent condition. In Singapore, the prevalence of excessive daytime sleepiness has been reported to be 9 per cent (Ng TP et al, Sleep Medicine 2005).

A ‘sleep debt’ builds until enough sleep is obtained.


Causes Causes of excessive daytime sleepiness include the following. It is commonly caused by more than one of these causes. 1. Inadequate sleep The amount of sleep needed each night varies amongst different people.

Most need seven to eight hours of uninterrupted sleep to maintain alertness the following day. A habitual sleep period of less than four to five hours daily is generally insufficient to maintain normal daytime alertness and is likely to cause excessive daytime sleepiness. If you do not get enough sleep even on a single night, a ’sleep debt’ begins to build and increases until sufficient sleep is obtained. Excessive daytime sleepiness occurs as the debt accumulates. If you do not get enough sleep during the work week, you may tend to sleep longer on the weekends or days off to reduce your sleep debt. 2. Sleep disorders Sleep disorders such as obstructive sleep apnoea, narcolepsy, restless legs syndrome and insomnia may cause excessive daytime sleepiness.

• Obstructive sleep apnoea is a

potentially serious disorder in which your breathing is interrupted during sleep. This causes you to awaken many times during the night and experience excessive daytime sleepiness.

• Narcolepsy will cause excessive

daytime sleepiness during the day, even after getting sufficient sleep at night. You may fall asleep at inappropriate times and places.

• Restless legs syndrome causes a

person to experience unpleasant sensations in the legs. These sensations frequently occur in the evening, making it difficult for you to fall asleep, leading to excessive daytime sleepiness.

• Insomnia is the perception of poor-

quality sleep due to difficulty falling asleep, waking up during the night with difficulty returning to sleep or waking up too early in the morning.

3. Medications Some medications may disrupt sleep and cause sleepiness. Examples include sedating antihistamines, sedatives, antidepressants and seizure medications. 4. Alcohol Alcohol is sedating and can, even in small amounts, make a person more


sleepy and at greater risk of car crashes and performance problems. 5. Caffeine Caffeine in coffee, tea, soft drinks or medications makes it harder for many people to fall asleep and stay asleep. Caffeine stays in the body for about three to seven hours, so even when taken earlier in the day, it may cause problems in falling asleep at night.

Caffeine stays in the body for three to seven hours.

6. Nicotine Nicotine from cigarettes is also a stimulant and makes it harder to fall asleep and stay asleep.


7. Medical conditions Chronic medical conditions such as asthma, heart failure, depression, rheumatoid arthritis or any other chronically painful disorder may also disrupt sleep and lead to excessive daytime sleepiness. Excessive daytime sleepiness may also occur following head injury and rarely, due to brain tumour. 8. Sleep-wake cycle disturbance (such as shift work) Most shift workers get less sleep over 24 hours as compared to day workers. The human sleep-wake system is designed to facilitate the body and mind for sleep at night and wakefulness during the day. These natural rhythms make it difficult to sleep during daylight hours and to stay awake during the night hours, even in well-rested individuals. Sleep loss is greatest for night shift workers, those who work early morning shifts and female shift workers with children at home. Shift workers who try to sleep during the day are frequently interrupted by noise, light, the telephone, family members and other distractions.

Get help if you feel sleepy despite getting enough sleep.



Signs of excessive daytime sleepiness may include:

If you feel sleepy during the day despite getting enough sleep, consult your physician who will evaluate the possible causes and advise on the appropriate management. It is important to get proper diagnosis and treatment of the underlying cause of the sleepiness. Your physician may refer you to a sleep disorders clinic for a comprehensive evaluation of your problem.

• Difficulty paying attention or • • • • • •

concentrating at work, school or home Poor performance at work or school Difficulty in staying awake when inactive, such as when watching television or reading Difficulty remembering things Need to take naps on most days Sleepiness that is noticed by others Falling asleep while driving


Management Identifying the cause(s) of excessive daytime sleepiness is the key to its management. Treatment is directed towards the specific underlying cause. Obstructive sleep apnoea is generally treated with continuous positive airway pressure (CPAP). In general, medications do not help problem sleepiness and some medications may make it worse. Medications may be prescribed for patients in certain situations. Short-term use of sleeping pills has been shown to be helpful in patients diagnosed with acute insomnia. Long-term use of sleep medication is recommended only for treatment of specific sleep disorders. Stimulants to maintain alertness are used in the treatment of narcolepsy.

Self/Home care • Get enough sleep

Many people do not set aside enough time for sleep on a regular basis. A first step may be to evaluate your daily activities and sleep-wake patterns to determine how much sleep is


obtained. If you are getting less than eight hours of sleep, more sleep may be needed. A good approach is to gradually move to an earlier bedtime. For example, if an extra hour of sleep is needed, try going to bed 15 minutes earlier each night for four nights, then keep to the last bedtime. This method will increase the amount of time in bed without causing a sudden change in schedule.

• Avoid caffeine

Avoid beverages containing caffeine (coffee, tea and some soft drinks). Caffeine can help to reduce sleepiness and increase alertness but the effect is temporary. It can cause problem sleepiness to become worse by interrupting sleep.

• Avoid alcohol

While alcohol may shorten the time it takes to fall asleep, it can disrupt sleep later in the night, leading to poor quality sleep and adding to problem sleepiness. Chronic use of larger quantities of alcohol can also lead to alcohol dependency.

Sleep Disorders Unit Singapore General Hospital | Tel: 6321 4377

Sleep-disordered breathing and snoring Sleep-disordered breathing refers to a group of breathing conditions in sleep. Obstructive sleep apnoea (OSA) is the most common sleep-disordered breathing condition. It is a potentially serious disorder associated with snoring, in which your breathing is repeatedly interrupted during sleep. This causes you to awaken many times during the night and experience daytime sleepiness.

Snoring may be a symptom of a spectrum of problems from simple snoring without sleep-disordered breathing to snoring associated with OSA. Snoring may be a symptom of partial airway obstruction. The partial obstruction may lead to complete airway obstruction that is seen in OSA. In a local study, approximately 24 percent of adults are loud habitual snorers and about 15 percent of adults are estimated to have OSA (Puvanendran K et al, Sleep Research Online 1999).

Causes The sounds of snoring are caused by the vibration or flapping of tissues lining the upper air passages. Snoring is mostly due to multiple factors. They are:

Not everyone who snores has obstructive sleep apnoea.


• Relaxation of muscles causing

the walls of the upper airway to fall together, causing them to vibrate. • Swelling of the tissue in the walls, for example, due to anatomical or injury may cause narrowing. • The tongue falls back into the throat when sleeping on the back, contributing to the snoring. • Nasal blockage such as nasal allergy or deformities of the nasal septum (the cartilage partition between the two sides of the nose) can cause poor nasal airflow and set the soft tissues of the palate (roof of the mouth) and throat vibrating. Individuals with OSA have a narrower and more collapsible upper airway causing repeated upper airway obstruction during sleep. When breathing stops, the level of oxygen in the bloodstream falls. The brain senses this decrease in oxygen and rouses the person from sleep. With awakening, the muscles at the back of the throat become more active and hold the airway open so that breathing can resume.


Symptoms Soft, rhythmic snoring is not believed to have any significant adverse heath effects. However, when snoring becomes loud, breathing may be impaired and sleep disrupted. The repeated awakenings make it hard to get a good night’s sleep, resulting in poor sleep quality and sleep deprivation. The upper airway obstruction leads to decreased oxygen supply to the brain, heart and other organs and puts tremendous stress on the heart and body, leading to medical consequences in the long run.

Someone with OSA may present with loud and habitual snoring, excessive daytime sleepiness, feeling unrefreshed despite adequate sleep hours, falling asleep while driving,

depression, irritation, decreased libido and morning headaches. Their sleep partners may also notice gasping and choking episodes during sleep. As the lack of sleep is very stressful, affected individuals may become irritable, undergo changes in personality, or have difficulty with memory. Untreated OSA may lead to high blood pressure. There are also higher incidences of ischaemic heart disease, irregular heart rhythm and strokes in individuals with OSA. When OSA is severe, heart failure may occur. Untreated OSA is also associated with increased risk of sudden death and premature death.

problems are the more common causes of adult snoring. Other factors which may influence the snoring condition and the development of OSA are obesity, ageing and associated loss of general muscle tone, throat congestion due to reflux of stomach acid (heartburn); and the effects of alcohol, sedatives and smoking.

Risk factors Any condition that contributes to the narrowing at the back of the throat such as enlarged tonsils or adenoids favour the development of OSA. Large tonsils are the most common cause of snoring and sleep apnoea in infants. They can also be the occasional cause of problems in adults although nasal and soft palate

Snoring and obstructive sleep apnoea are more common in males.


In obesity, excessive fat accumulation in the upper airway may amplify an existing anatomic narrowing of the upper airway that was causing minimal obstruction previously. Snoring and OSA are also more common among males and in individuals with a genetic predisposition leading to facial and jaw abnormalities.

A sleep study records the number of irregular breathing events and their duration, the oxygen levels in the blood (measured by a device placed on the finger), the heartbeat, the snoring pattern, the amount and quality of sleep as well as the effect of sleeping positions on breathing.

Diagnosis Consult your physician if you have loud snoring or excessive daytime sleepiness despite getting enough sleep. Your physician will evaluate the possible causes and advise on the appropriate management. Your physician may refer you to a sleep disorders clinic for a comprehensive evaluation of your problem. A thorough examination of the nose, mouth, throat and neck is performed. In someone with significant snoring, sleep apnoea needs to be ruled out. The evaluation usually involves an overnight monitoring of sleep, called a sleep study or polysomnogram.


Medications are not effective in treating obstructive sleep apnoea.

Treatment Effective treatment is available for almost all patients. Treatment of both snoring and OSA requires a multidisciplinary approach. 1. Treatment for snoring The treatment of snoring is divided into medical and surgical options. The

treatment choice is individualised. In the treatment of snoring, a ’staged’ approach is often used, which generally involves medical therapy first, followed by consideration of surgery, if medical therapy is unsuccessful. Medical For patients with snoring and mild OSA, a conservative approach is usually recommended. These include: • Weight loss • Avoidance of alcohol • Sedative medications. Sedatives relax the muscles at the back of the throat and may depress breathing. • Nasal congestion is also treated with medications. Nasal obstruction increases the frequency of snoring and disordered breathing during sleep. • Sleeping on the sides rather than on the back. This position prevents the tongue and soft palate from collapsing against the back of the throat and blocking the airway. Surgical Surgical procedures for the treatment of snoring may include nasal, palatal, jaw, tongue and neck surgery. The

surgical procedure recommended will depend on the location of the tissues contributing to the snoring. 2. Treatment for OSA Indications for treatment of OSA include excessive daytime sleepiness affecting daytime performance, moderate to severe OSA and cardiovascular complications (hypertension, ischaemic heart disease, irregular heart rhythm and stroke). Treatment of OSA can improve daytime sleepiness, prevent cardiovascular complications, decrease sleep apnoea-related road traffic and workplace accidents, and improve quality of life. A medical device called continuous positive airway pressure (CPAP) may be recommended for patients with moderate to severe obstructive sleep apnoea. This device delivers room air to the nose and back of the throat at a slightly elevated pressure to prevent the airway from collapsing during sleep. CPAP is safe, generally welltolerated and highly effective. This device must be worn nightly and long-


term CPAP compliance is essential for its effectiveness. Dental appliances that reposition the lower jaw and tongue have been helpful in some patients with mild OSA and snoring. Dental appliances have to be worn every night. Dental and lower jaw joint side effects may prevent compliance. Surgery may be recommended for treatment of OSA for some individuals. Surgery is individualised and may range from procedures designed to open the nose and enlarge the back of the throat. Medications are ineffective in treating OSA.

Self/Home care Some useful suggestions for snorers:

• Reduce weight if you are obese. • Avoid taking sleeping pills/

sedatives. Certain sleeping pills may cause the upper airway to relax, leading to snoring.

• Avoid consuming alcohol after

6pm. Alcohol causes relaxation of muscles of the upper airway.

• Sleep on your side and avoid sleeping on the back.

• Quit smoking. Smoking causes swelling of the tissues of the upper airway, which results in snoring.

• Allow your bed partner to fall asleep before retiring to bed.

• Provide earplugs for your bed partner.

Sleep Disorders Unit Singapore General Hospital | Tel: 6321 4377


Obstructive sleep apnoea Obstructive Sleep Apnoea (OSA) is a condition in which the upper airway collapses during sleep. This creates an effect similar to that of being repeatedly choked – you are trying to breathe, but air cannot get in as the throat is blocked.

Sleep patterns get disrupted repeatedly because of this, resulting in nonrefreshing sleep. As a result, patients typically feel very tired throughout the day and have difficulty maintaining alertness. They fall asleep watching television, sitting in a bus or car, or even, in extreme cases, when talking on the telephone! During these episodes, there are recurrent dips in the blood oxygen levels, putting stress on the heart.

What if OSA is left untreated?

Even a short sleep arousal can lead to unrefreshing sleep.

OSA can cause serious health problems. In addition to affecting the quality of your life due to disrupted sleep patterns, OSA can lead to: • Memory loss • Stroke (Almost 70% of people who have had a stroke have OSA) • Hypertension (>35% of people with sleep apnoea suffer from hypertension) • Diabetes • Depression • Increased risk for heart attack (in >35% of patients with OSA)


• Increased risk of motor vehicle

accidents (seven times more likely to occur in patients with OSA) • Increased risk of work-related accidents • Decreased quality of life

Symptoms • Loud, frequent snoring • Your bed partner notices that you

periodically stop breathing during your sleep and gasp for breath • Excessive daytime sleepiness and fatigue • Unrefreshing sleep Not everyone who snores has OSA. I sleep through the night without recurrent awakenings, does this mean I do not have OSA? No. Most people with OSA do not realise that they are being awakened to breathe repeatedly throughout the night. This is because the arousal is short and most people become accustomed to this. However, even the slight short arousal is enough to disrupt the pattern of sleep leading to unrefreshing sleep.


Diagnosis It is best to see a sleep specialist to confirm the diagnosis. In the initial consultation, a thorough sleep history will be taken to assess for OSA. If OSA is suspected, an overnight sleep study is recommended to confirm the diagnosis of OSA.

What is a sleep study? A sleep study or polysomnogram (PSG) is an overnight diagnostic test done in a Sleep Laboratory. The PSG monitors the different stages of sleep, heart rhythm, muscle activity, breathing effort and oxygen levels during sleep. The severity of OSA can also be determined.

Treatment A very effective treatment for OSA is continuous positive airway pressure (CPAP) therapy. CPAP therapy is considered the gold standard and most effective non-surgical treatment

for OSA. Depending on the severity of OSA and the upper airway anatomy, other treatment options include weight loss, wearing of appliance during sleep and surgery.

Continuous Positive Airway Pressure

How does CPAP therapy work? Continuous Positive Airway Pressure (CPAP) works by quietly delivering air through the nasal passages to keep the upper airway open. This allows you to breathe uninterruptedly during sleep. There are two important parts of the CPAP machine that need to be decided on by careful consultation with your sleep physician prior to using CPAP.

They are: 1. The mask: CPAP is administered through a mask that seals either the nose, mouth or both the nose and the mouth. There are a variety of masks that can be used. Most of these are made from a soft silicon or gel to maximise comfort. The mask chosen for you will be fitted by the sleep technician to suit your facial structure and breathing habits. The first step in choosing the type of interface you should use is to establish how you breathe naturally (through the nose, mouth or both). There are different types of interfaces to suit different needs. They include: • Nasal masks (for nose breathers) • Nasal pillows (for nose breathers) • Full face masks (for nose and mouth breathers) • Oral-nasal masks (for nose and mouth breathers) • Oral masks (for mouth breathers) • Cloth masks


2. The Machine: Most CPAP machines today are small – about the size of a bedside alarm clock and are designed to be portable. Although many modern machines have sophisticated software that can detect obstruction and self-adjust the delivered pressure (auto-titrating machines), the settings (how much pressure needs to be delivered to keep the throat passage open) should be determined after consultation with your sleep specialist. Too high a pressure can be uncomfortable and also cause problems (e.g. increased leakage, problems with sinusitis, etc); too low a pressure will not effectively treat the sleep apnoea. Some machines have special modes that allow you to breathe out more easily, or can deliver a different pressure depending on whether you are breathing in or out. The exact type of machine needed is determined by the severity of the sleep apnoea and your upper airway structure.


What happens after OSA is treated? People with OSA who start using CPAP conscientiously report feeling more energetic and less sleepy during the day. Some even report feeling better after the first day of treatment. The benefits of CPAP include: • Reduction or elimination of apnoea and snoring • Feeling more rested and alert during the day • Improved blood oxygen levels, reducing health risks caused by sleep apnoea • Lowered blood pressure in hypertensive people 24 hours a day • Less strain on the heart • Sleep patterns returning to normal Sleep Disorders Unit Singapore General Hospital | Tel: 6321 4377

Surgical treatment for snoring and obstructive sleep apnoea Snoring and obstructive sleep apnoea (OSA) are common medical conditions that affect between 15-50% of the adult population worldwide. Snoring, due to vibration of tissues in the throat, can be a symptom of partial upper airway obstruction. The partial obstruction can lead to complete airway obstruction – a medical condition called obstructive sleep apnoea (OSA). In Singapore, about 15 percent of adults have OSA.

The throat

The upper airway from the nose to the windpipe

Indications for treatment of OSA include excessive daytime sleepiness with altered daytime performance, moderate to severe OSA, decreased blood oxygen saturation level and cardiovascular complications.

Normal airway

OSA airway


Surgical treatment for obstructive sleep apnoea is indicated if the patients are unable to tolerate or not willing to try continuous positive airway pressure (CPAP) treatment and have failed other conservative methods.

Treatment If a patient wants treatment, several options exist that are directed at the soft palate, nasal and base of tongue. Most treatments are directed at the soft palate (soft tissue at the back of the roof of the mouth) since this is the most common site of snoring. Surgery of the soft palate is effective in 80-90 percent of cases and can be associated with postoperative pain for 7-10 days. A minimally invasive technique like radiofrequency (RF) of the soft palate results in less pain

and can be done as a day surgical procedure. Radiofrequency of the soft palate may have to be repeated two to three times to achieve the desired results. In the nose, normal structures called turbinates may be enlarged from allergic rhinitis causing airflow blockage. Reduction of the turbinates using radiofrequency or surgical reduction (turbinectomy) may be performed. The septum that

Radiofrequency of the inferior turbinate.

Uvulopalatal flap (selected patients may have higher success rate) – a modified uvulopalatopharyngoplasty.


Radiofrequency of the tongue base can reduce tongue base obstruction.

divides the nose into two sides may also be deviated and needs to be straightened.

during sleep. These procedures have been used for years and clinical outcomes have verified their use.

The base of tongue and lingual tonsils (lymphatic tissues at the back of the tongue) may be enlarged, impeding airflow during sleep. Obstruction at these sites can be treated by a variety of methods depending on severity. Minimally invasive radiofrequency of the tongue base may require two to three treatments to achieve the desired result.

Types of Surgeries

Tracheostomy Tracheostomy involves creating a hole in the trachea, directly bypassing the upper airway obstruction. It is used in people with refractory base of tongue obstruction and in the morbidly obese with medical conditions that contraindicate surgeries that are more extensive. Though the success rate is 100 percent, this option is usually not accepted by patients and with the introduction of CPAP, it is seldom used to treat OSA.

Surgical procedures serve to remove or reposition tissues that partially or completely block the upper airway

Nasal Surgery Nasal airway obstruction caused by bony, cartilaginous or enlarged 27


Nasal passage with sinuses

Nasal septum and upper airway

tissues can interfere with nasal breathing during sleep. An open nasal airway establishes normal breathing and minimises mouth breathing. Mouth breathing in OSA individuals worsens the posterior airway by allowing the tongue to fall back. Establishing an open nasal airway passage can improve CPAP tolerance and compliance. Techniques include straightening the septum, turbinectomy and nasal valve reconstruction.

The traditional Uvulopalatopharyngoplasty (UPPP) and many variations of it can be used. Most surgeons have shied away from the traditional UPPP in favour of modified techniques and surgical flaps (like uvulopalatal flap, extended uvulopalatal flap, lateral pharyngoplasty) as these have fewer complications, are less ablative and have a higher success rate.

Palatal Surgery Abnormal structures at the palate level include large tonsils, redundant lateral pharyngeal mucosal, thick and long soft palate and hypertrophied posterior tonsillar pillar muscles and mucosal. All these contribute to a narrow airway at the palatal level.


In carefully selected patients, the success rate may be 50-60 percent but falls to a low of 5-30 percent in unselected patients. This is because of failure to address tongue base and hypopharyngeal obstruction.

Midline glossectomy – part of the bulky tongue can be removed to improve breathing.

Hypopharyngeal and Base of Tongue Surgery Compared to the nasal and oropharyngeal level, obstruction at the hypopharyngeal (base of tongue) level is a very complex issue as the large tongue base tissue collapses easily during sleep.

Obstruction at this level may be bypassed via a tracheotomy or by either increasing airway size to make more room for the tongue or reducing the tongue size. Both soft tissue techniques and skeletal work may be required. Soft tissue work involves removing the midportion of the tongue (median glossectomy, lingualplasty or volumetric reduction by radiofrequency). Transoral robotic surgery can be used to access this area. Skeletal advancement techniques can increase the airway size and tension on the tongue so that even if the tongue falls back during sleep it does not obstruct the airway. This procedure includes inferior sagittal mandibular

Genial tubercle advancement - tongue muscle is pulled forward to increase posterior airway space and to increase tension of the tongue to reduce obstruction during sleep. 29

In maxillomandibular advancement surgery the lower jaw and midface is moved forward to increase posterior airway space.

osteotomy, genioglossus advancement and hyoid suspension. Combining nasal/palate and tongue base surgery, the success rate can reach 70-80 percent.

Transoral Robotic Surgery (TORS) for Obstructive Sleep Apnoea The da Vinci robotic surgery system allows the surgeon superior access and view of the tongue base and hypopharyngeal area not previously possible. It allows the surgeon to address airway obstruction secondary to lingual tonsillar hypertrophy, tongue base hypertrophy and floppy epiglottis.

Maxillomandibular Advancement Surgery Maxillomandibular advancement surgery is a more aggressive procedure, usually saved for when more conservative surgery fails. It involves the forward movement of the lower jaw and midface and gives the tongue more room, opens the airway more and places additional tension on the tongue base. The individualised use of soft tissue and skeletal procedures for upper airway reconstruction ensures that the most conservative treatment is offered and the possibility of unnecessary surgery reduced. 30

The da Vinci Transoral Robotic Surgery (TORS) for OSA.

Sleep Disorders Unit Singapore General Hospital | Tel: 6321 4377

Insomnia Insomnia is one of the most common sleep problems in the general population. In Asia, a survey of the South Korean population found that 17% had at least three nights of insomnia each week. Another study in Hong Kong found 11.9% with insomnia.

Women, older people and worriers are at higher risk of insomnia.

Causes and Risk Factors There are many causes of insomnia and it can be due to a single factor or combination of factors. Women, older people and worriers are at higher risk of having insomnia. Jetlag, shift work or a noisy sleeping environment are common reasons for insomnia.

Life stressors such as difficulties at work or the death of loved ones can also cause insomnia. Unhealthy sleeping practices termed as ’poor sleep hygiene’ can also result in insomnia. Some examples include drinking caffeinated drinks in the evening. Some people may also take frequent naps during the weekends leading to insomnia on Sunday nights.


Insomnia can be a hint of a more serious underlying psychiatric condition such as depression or an anxiety disorder.

This can, in turn, lead to feelings of irritability, tiredness and poor concentration. As a result, productivity at work may dip. You may feel less fulfilled and get less satisfaction from hobbies and relationships.

Long-term misuse of medications like sleeping pills or alcohol can also result in insomnia.


Health problems like physical illnesses can also cause insomnia. These conditions can be those that result in pain (like chronic back pain) or frequent urination (like enlarged prostate gland in older men).

The doctor will take a full sleep history from you and your sleeping partner, if any. This may be followed by a physical examination. Laboratory tests including blood tests may also be ordered.

Sometimes, no specific causes can be pinpointed. These are termed as ’Primary Insomnia’.

In a specialist clinic dealing with sleep disorders, the doctor may want to admit you to observe the sleep to see if specific medical conditions (e.g. obstructive sleep apnoea where there are abnormal pauses in breathing during sleep) are suspected. This is known as a sleep study.

Symptoms You may have difficulty falling asleep, frequent awakenings in the middle of the night or waking up in the wee hours of the morning. You may also experience non-restorative sleep i.e. feeling unrefreshed in the morning.


In the sleep history, the doctor may ask for information on the following:

1. Duration: Whether the insomnia has persisted for days, weeks or months 2. Frequency: How many days in the week it occurs 3. Type: Whether you have difficulty falling asleep, maintaining sleep or experience early awakening 4. Environmental factors such as noise level, whether the surroundings are uncomfortable or if you work shifts 5. Evidence of poor sleeping habits such as frequent naps, lying in bed throughout the day or drinking caffeinated drinks at night

Treatment The doctor will deal with the underlying causes that are working together to cause the insomnia. Behavioural Methods The doctor may also employ behavioural methods to improve sleep. However, these methods require time and effort to see results. These methods include: 1. Good sleep hygiene 2. Relaxation techniques (e.g. deepbreathing exercises) 3. Hypnosis 4. Learning how to cope with stress 5. Engaging a trained therapist for Cognitive Behavioural Therapy

Don’t surf the internet in bed.


Medication There are many different medications for insomnia. These range from milder ones like antihistamines (more commonly used for the common cold or itch) to stronger medications that can also be used for anxiety and depression. Lastly, there are medications that are used purely for sleep and some of these can be very addictive. Therefore, this last category of medication is usually used only for short periods. While medications can offer rapid relief, they confer only short-term benefits. Many of them also have side effects. Some sleeping pills are highly addictive. In elderly patients, the drowsiness from the sleeping pills can lead to a higher risk of falls. This, in turn, leads to a higher risk of hip fractures that have devastating consequences for older people. The doctor will advise you carefully before starting you on these medications.

Sleep Hygiene Advice Good sleep hygiene is a behavioural method that can be used to improve sleep. The sleep hygiene advice listed below can be easily practiced at home. However, you may need to keep to them for many days or even weeks before any improvement can be seen. They are: 1. Keep to the same sleeping and waking time, even during weekends 2. Exercise regularly but not three to four hours before bedtime 3. Avoid taking naps 4. Avoid activities like reading or surfing the internet in bed 5. Avoid caffeinated drinks like coffee, tea or colas 6. Avoid heavy meals, alcohol or smoking before sleep 7. Have a conducive sleep environment that is cool and quiet

Sleep Disorders Unit Singapore General Hospital | Tel: 6321 4377


Circadian rhythm: Coping with jet lag and shift work Commonly known as the ’body clock’, the circadian rhythm is an innate cyclical rhythm that regulates many bodily functions automatically throughout the day, and does not require conscious control. There are those that are apparent to us, such as the sleep-wake cycle and the digestive cycle, for which we feel sleepy or hungry when we reach a certain time of the day. There are also those that are not so obvious such as core body temperature and the release of hormones into the bloodstream. In human beings, this innate rhythm cycles between the duration of 24.2 to 24.9 hours, just slightly longer than a day. This could potentially create a messy situation where we could fall asleep or need to eat at very inconvenient timings, over a period of time.

Fortunately, this ’clock’ is synchronised to the 24-hour day by environmental inputs, most importantly by sunlight, as well as by social rhythm such as common meal times, work schedules, and physical exercises. Genetics largely influence the variations between individuals, hence there are people whom we recognise as ’larks’ (preferring to sleep early in the night) and ’night owls’ (ability to stay up late into the night). Genetics also determines the ability of individuals to adapt to time cues in the daily cycle, and hence the ability to ’tune their clocks’. With age, this innate rhythm can also change in its cycle length, commonly reflected through changes in sleep pattern as one grows older.


1. Jet Lag This is a transient condition in which the circadian rhythm is temporarily out of synchronisation with the external environment when a person travels across several time zones rapidly.


Jet lag is a temporary condition which can be managed.

Problems with Circadian Rhythm It is important that you keep to a regular sleep schedule, as this maintains synchrony of the ‘body clock’ with the demands of social activities and duties. Any situation that desynchronises the circadian rhythm and the social rhythm will result in sleep difficulties as well as problems in maintaining alertness. The most common causes of disruption to circadian rhythm are jet lag and shift work.


The symptoms are usually daytime fatigue and sleepiness, insomnia, stomach upsets, moodiness and feeling of unsteadiness. Some may also experience chills, and others have episodes of feeling hot and sweaty. As our body clock runs slightly longer than 24 hours, jet lag is worse when we travel eastwards than when we travel westwards. It is easier to lengthen the day (delaying going to bed) than to shorten it (trying to fall sleep earlier). After travelling from east to west, early waking is the main problem, as oppose to difficulty falling asleep when travelling from west to east. Our circadian rhythm will eventually synchronise with the local time at the destination, at a rate of roughly one day per hour of time difference.

Tips for managing jet lag: 1. If you are able to, choose a destination that involves flying westwards. 2. Choose daytime flights to avoid losing sleep. 3. Use sleeping aids such as blindfolds, earplugs, and neckrests to help you sleep during the flight. 4. Adjust to local time by keeping to local routines at your destination, such as taking meals when the locals do. 5. Try to keep awake during daytime. Staying in a brightly lit environment will facilitate the adjustment of the body clock. Adjust your body clock to manage shift work sleep problems.

Flying westwards can cause less jet lag.

6. If necessary, naps should be short, and planned so as not to affect night time sleep. 7. Melatonin supplement may be helpful for jet lag symptoms and improving sleep when taken near bedtime. 8. Exercise during the day.


9. Caffeine may help in maintaining alertness. 10. Plan ahead for your journey and make allowances for adjustments where possible. 2. Shift Work Shift workers are people who work non-traditional hours, which may be exclusively at night, or on rotating shifts. They often face problems similar to jet lag, even without crossing time zones. The differences between their ’day’ during which they are working, and the natural day-night cycle has resulted in desynchronised circadian rhythm. While some may have no problems adapting to this demand, many suffer from sleep problems. They may experience insomnia, and may not get enough sleep during the day as the brain remains active, culminating in sleep deprivation. This eventually leads to wake time sleepiness and impaired work performance. They may have sleep problems even on their days off.

The main objective of managing shift work sleep problems is to try to resynchronise the circadian rhythm to the work schedule as quickly as possible. In addition, we try to improve on the quality and duration of sleep at bedtime to reduce effects of sleep deprivation. This is typically easier to achieve for people who work regular shift, and treatment is similar to that for jet lag which is to adjust the body clock to a new ‘daytime’. What if I work rotating shifts? The day before night shift: Get up at your usual time and have meals as usual. Take a two to three hour nap in the late afternoon or early evening to reduce your sleep debt before the start of your duties. During the shift: Take a power nap for 30 minutes if possible to reduce the sleep debt. Avoid too long a nap as you may have more difficulty getting into an alert state. Day after the night shift: If you have to work another night shift, get in six


to eight hours of sleep when you get home. If you cannot get a long enough sleep, nap in the late afternoon or early evening as described earlier. If you do not have to work nights again, catch a short two to three hour nap after you get home and stay awake till your normal bedtime. Tips to cope with rotating night shifts: 1. Maintain a regular sleep routine on normal work days and on rest days. 2. Plan naps to reduce sleep debt during night shift periods, and catch up on sleep on rest days. 3. Eat properly and maintain sufficient exercises to provide cues for maintenance of circadian synchronisation.

Tips to sleep better during the day: 1. Maintain general sleep hygiene principles. Avoid strenuous exercises, caffeine and nicotine four hours before bedtime. 2. On your way home from night shift, use dark sunglasses to reduce the effects from the bright morning sunlight which may influence the circadian rhythm. 3. Keep a conducive sleep environment: Use dark curtains, and earplugs if necessary. 4. Learn some relaxation skills and avoid trying too hard to get to sleep. 5. Avoid the temptation to defer sleep to attend to personal administrative or social tasks, plan to do these after your rest period. 6. If necessary, see your GP for shortterm prescription of sleeping aids. Use these medications on an as needed basis only.

Scheduling enough time to sleep is important and should be actively prioritised and planned for. Good sleep is essential to well-being, and allows one to function efficiently and safely. Sleep Disorders Unit Singapore General Hospital | Tel: 6321 4377


Movement disorders in sleep Movements during sleep are quite common, especially among children. They usually represent a generally benign and non-intimidating condition. These are disorders disrupting sleep and have undesirable physical or verbal behaviours or experiences. They occur in association with sleep, in specific sleep stages or in the sleep-wake transition phases and are divided into Primary and Secondary under the terminology of Parasomnias.

EEG (Electroencephalogram) and PSG (Polysomnogram) recordings are essential to differentiate these conditions.

Sleepwalking Sleepwalking is common in children between the ages of 5 and 12 but can persist into adulthood or, rarely,

Primary Parasomnias The major Primary Parasomnias include Sleepwalking, REM Behaviour Disorder (RBD), Restless Legs Syndrome and Periodic Leg Movements, and Nightmare Disorder and Sleep Terror which are seen more in children. These can sometimes be mistaken for seizures. The characteristic clinical features combined with


Sleepwalking, common in children, can persist into adulthood.

begin then. It usually starts abruptly within the first one-third of sleep and generally lasts less than 10 minutes. Sleepwalking episodes are usually uneventful; injuries and violent episodes are uncommon. Episodes can be precipitated by sleep deprivation, fatigue, other illnesses and sedatives/ hypnotics. General precautionary measures should be put in place when a person has been diagnosed with sleepwalking. The environment has to be made safe i.e. lock doors and windows, remove dangerous items and other hazards.

REM Behaviour Disorder (RBD) RBD is an important REM sleep parasomnia commonly seen in elderly patients. The classic characteristic feature is the loss of muscle tone partially or completely during REM sleep. There is also the appearance of various abnormal motor activities during sleep. You may experience violent and dream-enacting behaviour during REM sleep. This can cause selfinjury or injury to your bed partner. RBD may be idiopathic or secondary and most cases are now thought to be secondary and associated with neurodegenerative disorders. RBD has been linked to dopamine dysfunction based on PET scan findings. REM sleep without muscle atonia is the most important finding in the polysomnogram.

Violent or dream-enacting behaviour can happen in REM Behaviour Disorder.


Treatment Treatment for RBD is usually initiated with clonazepam at bedtime and doses may have to be adjusted. It has been shown to be beneficial in the long-term. Drug discontinuation often results in prompt relapse. Other drugs such as tricyclic antidepressants and dopaminerelated medications have been tried but effects are unpredictable. Restless Legs Syndrome (RLS) RLS is the most common movement disorder. There is no diagnostic test for RLS. The diagnosis rests entirely on clinical features. RLS is a lifelong sensory-motor neurological disorder

Women are more likely to have Restless Leg Syndrome.


that often begins at a very young age but is mostly diagnosed in the middle or later years. It is more prevalent with increasing age and then plateaus for some unknown reason around age 85 to 90. In several surveys, it was found that it tends to be more prevalent in women. The disease is chronic and progressive. There are studies indicating that there is a possible genetic link. The sensory manifestations of RLS include intense disagreeable feelings which are described as creeping, crawling, tingling, burning, aching, cramping, knife-like or itching sensations. These usually occur between the knees and ankles causing an intense urge to move the limbs to relieve these feelings. Sometimes it can occur in the arms or other parts, especially in advanced stages. Most of the movements, especially in the early stages, are noted in the evenings when you are resting in bed. In severe cases, movements may be noted in the daytime when sitting or lying down.

Periodic Leg Movements (PLM) At least 80% of RLS patients have Periodic Leg Movements (PLM) in sleep and sometimes in wakefulness (PLMW). The condition affects sleep profoundly because there is not only a problem of initiation of sleep but maintaining sleep may also be difficult because of PLMs. The causes of PLMs are uncertain. Most are idiopathic (have no apparent underlying cause) in nature but secondary causes like obstructive sleep apnoea, uremia, anaemia with iron deficiency, neuropathies, diabetes mellitus or certain drug withdrawals can also cause this. The causes of RLS are also uncertain. The movements are repetitive in nature and can involve one or both limbs. It lasts about two seconds and occurs in the earlier or middle stages of sleep. It usually occurs in the legs and involves upward movement of the big toe and flexion of the ankle. It can sometimes be seen at the knee and hip. Both legs are usually involved and the same movements can also occur in the arms.

Not all patients with PLMs have RLS. PLMs cause excessive daytime sleepiness but RLS commonly causes insomnia. Both RLS and PLMs generally undergo similar investigations including blood tests, nerve conductions, if necessary, and a polysomnogram.

Treatment If the cause is known, this should be treated. Caffeine, alcohol and nicotine should be avoided before sleep. Daily exercises and general physical therapies like hot and cold packs and massages can alleviate some of the symptoms. Drugs that can aggravate these conditions should also be avoided, if possible. These include diphenhydramine, SSRIs, lithium and betablockers. Symptomatic treatment includes the use of dopaminergic agents like levodopa, dopamine agonists like pramipexole, pergolide,


benzodiazepines like clonazepam, opioids and anticonvulsants like Gabapentin. Nightmare Disorder This is usually seen in children. The dreams are frightening and occurs in REM sleep and is associated with profuse sweating and arousal. The heart rate and respiratory rate are increased and the child remembers the dream. Sleep Terror Sleep Terror occurs during slow wave sleep and usually between the ages of five to seven years. There is a high incidence of family history of sleep terror. Episodes are characterised by extreme panic and sudden loud terrified screaming during sleep followed by physical activities. They can injure themselves. Recollection is partial or incomplete. Sleep-Related Bruxism Though this has not been generally thought to be a movement disorder, it is generally discussed under this because of its clinical features. It is characterised by grinding or clenching of the teeth during sleep


and associated with sleep arousals. Contraction of muscles associated with chewing leads to abnormal wear of the teeth, tooth pain, jaw muscle pain or temporal headache. There is usually no cause but can be associated with stressful situations or anxiety and seems to occur most frequently in highly motivated or vigilant individuals. Secondary Parasomnias These are disorders of other organ systems that may manifest during sleep. Examples are seizures, respiratory disorders, cardiac arrhythmias and gastroesophageal reflux. A good history and physical examination and relevant investigations should help exclude these. Sleep Disorders Unit Singapore General Hospital | Tel: 6321 4377

Sleepwalking Sleepwalking is characterised by complex behaviour (walking) while asleep. Nonsensical talking may accompany this at times. The eyes are usually open with a characteristic ’glassy’ look that appears to have a ‘going through you’ kind of appearance.

It usually occurs in middle childhood and adolescence but can persist into adulthood. There appears to be a genetic tendency. Stage 1, 2 and 3 are described as nonrapid eye movement (NREM) sleep. Rapid eye movement (REM) sleep is the last cycle which is usually associated with dreaming. There are four to five complete sleep cycles per night, each cycle consisting of all three stages and REM.

Sleepwalking appears to have a genetic link.


Sleepwalking usually occurs in the first or second cycle during stage 3. It is not usually seen during naps. The person is not aware and has no memory of his or her behaviour.

Causes Genetic It occurs more frequently in identical twins. The risk is ten times higher if a first-degree relative has a history of sleepwalking. Environmental The following factors can trigger sleepwalking:

• • • • • • • • •

Symptoms Episodes range from quiet walking to agitated running. Eyes are open with a glassy staring appearance. On questioning, responses are slow with simple thoughts. If returned to bed

Sleep deprivation Chaotic sleep schedules Fever Stress Magnesium deficiency Alcohol intoxication Sedative/hypnotic drugs Stimulants Antihistamines

Physiologic Pregnancy and menstruation can increase the frequency of sleepwalking.


Associated Medical Conditions Arrhythmias Fever Gastroesophageal reflux Night time asthma Night seizures Obstructive Sleep Apnoea Psychiatric disorders

• • • • • • •

Sleepwalkers will not remember the event.

without awakening, the person does not usually remember the event.


bunk beds

• Lock windows and doors • Remove obstacles in the room • Cover glass windows with heavy drapes

Usually no tests or exams are necessary but a medical evaluation may be done to rule out medical causes of sleepwalking. A psychological evaluation may also be done to exclude excessive stress or anxiety as a cause. Sleep tests may be done if the diagnosis is still unclear.

Treatment The following treatment options can be undertaken for a person with sleepwalking disorder: General Measures • Go to bed at the same time each night • Attain adequate sleep • Avoid napping • Avoid stress, fatigue and sleep deprivation • Moderate or relaxation exercises • Avoid any kind of stimuli prior to bedtime • Environment must be safe from harmful or sharp objects • Sleep on the ground floor and avoid

• Place alarm or bell on bedroom and windows, if necessary

Medical Treatment The underlying cause should be treated, for example, gastroesophageal reflux, obstructive sleep apnoea, seizures and other causes mentioned. Medications may be necessary in the following situations: • The possibility of injury is real • Continued behaviours are causing significant family disruption or excessive daytime sleepiness • Other measures have proven to be inadequate • Benzodiazepines have been shown to be useful for three to six weeks and then discontinued without recurrence of symptoms but occasionally frequency can increase briefly after discontinuing the medication Sleep Disorders Unit Singapore General Hospital | Tel: 6321 4377


Sleepy driving Sleepy driving is a serious problem that can lead to car crashes. Sleepiness causes motor vehicle accidents because it impairs concentration and can lead to the driver falling asleep at the wheel.

Microsleeps can overcome your best effort to stay awake.

Important aspects of driving impairment associated with sleepiness are reaction time, vigilance, attention, and information processing. The exact prevalence is not known in Singapore.


Sleepiness-related crashes is an under-recognised problem and may be categorised as fatigue and inattention. Although society today gives sleep less priority than other activities, sleepiness and performance impairment are responses of the human brain to sleep loss/ deprivation. There is currently nothing that can reduce the human need for sleep. Microsleeps, or involuntary intrusions of sleep or near-sleep, can overcome even the best intentions to remain awake. Accident Characteristics A typical crash related to sleepiness has the following characteristics: • It occurs during late night/early morning, or mid-afternoon • The crash is likely to be serious • A single vehicle leaves the roadway • The driver does not attempt to avoid a crash • The driver is usually alone in the vehicle

Risks for Sleepy Driving Crashes • Sleep loss

The need for sleep varies among people–sleeping eight hours per 24hour period is common, and seven to nine hours is needed to optimise performance. Sleeping less than four consolidated hours per night impairs performance on vigilance tasks. Acute sleep loss, even the loss of one night of sleep, results in extreme sleepiness. The effects of sleep loss are cumulative. Regularly losing one to two hours of sleep a night can create a ’sleep debt’ and lead to chronic sleepiness over time. Only sleep can reduce sleep debt. Sleep loss can be work-related or a lifestyle choice.

• Sleep quality The quality of sleep is also important. Sleep disruption and fragmentation leads to inadequate sleep and can negatively affect functioning. Sleep fragmentation can be caused by illness, including untreated sleep

disorders. Disturbances such as noise, young babies, children, activity and lights, a restless/snoring spouse, or job-related duties (e.g. workers who are on call) can interrupt and reduce the quality and quantity of sleep. • Driving patterns: Late-night driving between midnight and 6 am, driving in the mid-afternoon hours and driving for longer periods without taking a break. • Use of sedating medications, especially prescribed anxiolytic hypnotics, tricyclic antidepressants, and some antihistamines. • Untreated or unrecognised sleep disorders, especially sleep-related breathing disorders, obstructive sleep apnoea syndrome and narcolepsy. • Consumption of alcohol, which interacts with and adds to drowsiness. A combination of these factors increases crash risk substantially.


Sleepiness leads to slower reaction time.

Why Sleepy Driving Accidents Happen

perform repetitive tasks like driving, sleep comes quickly.

Sleepiness leads to accidents because it impairs human performances that are critical to safe driving.

Sleepiness leads to: • Slower reaction time: At high speeds, delay in reaction time can have a profound effect on crash risk. • Reduced vigilance • It takes longer for information on the roads to be integrated and processed.

People can use physical activity and dietary stimulants to cope with sleep loss and mask their level of sleepiness. However, when they sit still to


People at Highest Risk • Young people (ages 16 to 29), especially males

• Shift workers whose sleep are

disrupted by working at night or working long or irregular hours • People with untreated sleep apnoea syndrome (SAS) and narcolepsy

Assessment for Chronic Sleepiness The Epworth Sleepiness Scale (ESS) is an eight-item, self-report measure that quantifies individuals’ sleepiness by their tendency to fall asleep ’in your usual way of life in recent times’ in situations like sitting and reading, watching TV, and sitting in a car that is stopped for traffic. People with a score between 10 to14 are considered moderately sleepy, whereas a score of 15 or greater indicates severe sleepiness.

Preventive Measures To prevent sleepy driving and its consequences, you need to know the benefits of behaviours that help you avoid becoming sleepy while driving. These include: 1. Getting sufficient sleep and taking a short nap (15 to 20 minutes) when sleepy 2. Not drinking alcohol when sleepy 3. Limiting driving between midnight and 6 am 4. Taking caffeinated drinks/food e.g. coffee 5. Detection and treatment of illnesses that can cause excessive sleepiness like sleeprelated breathing disorders obstructive sleep apnoea syndrome and narcolepsy Sleep Disorders Unit Singapore General Hospital | Tel: 6321 4377


Common sleep conditions in infants, children and adolescents Sleep is Important Sleep is an important part of healthy growth and development in children, just like nutrition and physical activity. Contrary to the common perception that sleep is only a passive state during which the bodily processes slow down and the body rests itself at the end of the day, many active physiological processes do take place in the body during sleep. Amongst these are memory consolidation and growth hormone secretion, which are important physiological processes in children.

Children need sleep for growth and memory consolidation.


The paediatric sleep specialist is concerned with both the quality and quantity of sleep in children. Good sleep entails the child sleeping sufficient hours for his age, as well as restfully through the night.

What can affect sleep Sleep-related disorders such as obstructive sleep apnoea or sleep terrors can disrupt the child’s sleep. Medical conditions in children, such as uncontrolled asthma, allergic rhinitis and eczema, can affect the quality and duration of a child’s sleep. School work, as well as the encroachment of personal electronic devices in our daily life, may also impact on the quality and duration of sleep in older children. Effects of poor sleep Poor sleep can have adverse effects on cognitive performance and mood, metabolism, immunity and the cardiovascular system: • Sleep deprivation can affect daytime alertness, judgement, memory, reaction time and motor performance. • Inadequate sleep is associated with increased levels of anger, anxiety and sadness.

• Decreased slow wave sleep (one of

the stages of sleep) is associated with decreased growth hormone secretion during sleep. Inadequate sleep is correlated with insufficient leptin, a hormone involved in the regulation of carbohydrate metabolism and appetite, and associated with obesity. Short-term sleep debt impairs glucose metabolism, and over the long-term increases the risk of developing diabetes mellitus. Natural killer cells (a type of white blood cell involved in immunity against viral infections) in the body reduce in numbers during sleep deprivation. The effectiveness of influenza vaccines may be delayed in individuals who are sleep deprived. Sleep deprivation is associated with an increase in blood pressure during the night that lasts through the following day. Increased blood pressure and increased risk of stroke is associated with long-term sleep loss.


Sleep Requirements in Children Sleep architecture (the pattern and proportion of the different sleep stages during sleep) and requirements evolve with the development and maturation of the central nervous system as a child progresses from infancy through childhood and adolescence, to adulthood.

In general, sleep requirement decreases with age. A newborn sleeps an average of between 16 to 17 hours over a 24-hour period. In toddlers, sleep requirement decreases to between 12 to 13 hours. Pre-schoolers need to sleep between 11 to 12 hours, and school-going children between 10 to 11 hours. Adolescents require about 9 hours of sleep.

The pattern and timing of sleep also evolves with age, with consolidation of the nighttime and daytime sleep


in the first few years of life into nighttime sleep as the child matures developmentally. Newborns usually sleep between three to five hours (two to three hours in breastfed babies), and are awake for one to three hours in between. An infant typically takes mid-morning and afternoon naps, and only needs the afternoon nap by 18 to 24 months of age. By between three to five years of age, most children do not need naps. At the onset of puberty, adolescents develop a two-hour phase delay in their circadian rhythm, leading to a natural tendency to go to bed or sleep later. There can be, however, variations in sleep requirements, patterns, as well as tolerance to sleep deprivation between different individuals. In general, the duration of sleep is sufficient if the child feels well-rested on waking spontaneously, and is able to function normally throughout the day. When

there is inadequate sleep relative to the child’s natural sleep requirement, the child will have insufficient sleep. Some of the signs of insufficient sleep to look out for include: • Excessive daytime sleepiness • Mood disturbances • Behavioural problems such as inattention, hyperactivity, oppositional behaviour and poor impulse control • Impaired cognitive functioning such as poor concentration, impaired vigilance, delayed reaction time and learning problems

• Do not use the bed for any other

activity (e.g. reading, watching television, playing games on personal electronic devices, eating) other than sleeping. • Avoid using the bedroom for time-out or punishment. • Ensure that the bedroom is conducive to sleep, keeping it dark, quiet and comfortable during sleep time. • Avoid placing the computer, television, mobile phones and other personal electronic devices in the bedroom.

Good Sleep Hygiene and Practices Observing good sleep hygiene and practices will help your child achieve good sleep. The following are general advice for children. Please refer to later sections for specific advice for infants and specific sleep disorders. • Maintain a consistent sleep and wake time daily, including over the weekends.

Do not use the bed for other activities other than sleeping.


• Establish a regular relaxing routine

• •


before bedtime (e.g. brushing teeth, changing into pyjamas, reading of story). Go to bed only when tired or sleepy, rather than spending too much time awake on the bed. If your child is unable to fall asleep after 20 minutes, consider letting him get out of bed to do some low stimulation activity (e.g. quiet reading) and return to bed later to avoid association of the bed with sleeplessness. Avoid caffeine (e.g. coffee, tea, chocolate, cola and soda drinks) and nicotine (exposure to environmental tobacco smoke) four hours before bedtime. Avoid going to bed with a full stomach or when too hungry. Avoid stimulating activities before sleep (exciting television programs, playing games on personal electronic devices). Exercise regularly in the day or early evening, but avoid exercise or strenuous activities four hours before bedtime. Spend some daytime outdoors or in natural light daily.

Some children may have medical conditions that can affect their sleep, such as uncontrolled asthma, allergic rhinitis and eczema, which may cause them to wake up in the night because of cough, difficulty breathing or itch. Let your child’s doctor know if the medical condition is affecting his sleep so that the doctor can prescribe appropriate treatment to ease the symptoms. Some children may have underlying sleep-related disorders such as obstructive sleep apnoea. The most common groups of children at risk for obstructive sleep apnoea are overweight children and children with enlarged tonsils and/or adenoids (please refer to later section for other groups of children at risk for obstructive sleep apnoea). If your child is at risk, take note to see if he is snoring during sleep, and if his sleep is restful and comfortable, with no increased work of breathing. If you have concerns about your child having obstructive sleep apnoea, consult your doctor for a review. Your doctor will be able to refer your child to a paediatric sleep specialist if he suspects obstructive sleep apnoea in your child.

Sleep Advice for Parents of Newborns and Infants Newborn babies sleep round the clock in their first few months, and their sleep and wake times are often influenced by their need to be fed, changed or nurtured. Although most newborns sleep between 16 to 17 hours over a 24-hour period, sleep duration can vary between normal healthy babies, ranging between 11 to 20 hours. It is important that parents have the following awareness of how newborns and infants sleep, so that they can set realistic expectations for their newborns and themselves:

• Babies do not understand what is

’sleeping through the night’, many do not do so until they are more than three to six months old. Most babies do not sleep through most of the night before three to six months old. • Every baby is different; your baby may have different sleep patterns from other babies and still be normal and healthy.

Babies, before 3 to 6 months old, do not sleep through the night.

• Your baby will begin to sleep longer periods of time at night as he grows and develops over time.


All babies wake up spontaneously at least a few times during the night. They often require soothing and intervention from caregivers to fall back to sleep in the first couple of months. They generally develop the ability to self-soothe to sleep between the age of three to six months onwards, and parents should encourage their babies to learn to fall asleep independently early. Parents with newborns and infants may consider the following advice to help their babies develop this ability:

• Put your baby to bed when drowsy but still awake, so that he can learn to fall asleep on his own in his own crib/cot/bed.

If you are breastfeeding, avoid breastfeeding your baby to sleep, so that he does not associate this as a prerequisite for sleep. For similar reasons, you should also avoid bottle feeding your baby to sleep. Some parents find gentle rhythmic patting of their babies helpful in


settling them to sleep, but for the same reasons as before, it is best to stop the patting when the baby is quiet and about to fall asleep. Breastfeeding, bottle-feeding, patting, and other methods of settling your baby until he is completely asleep may result in sleep association with these conditions and make it difficult for him to go back to sleep if he wakes up during the night.

• Learn to identify signs of sleepiness in your baby. Newborns may express their need to sleep in different ways. Some fuss or cry, some indicate by rubbing their eyes, pulling their ears or other gestures, some yawn or lose focus on ongoing play or activity. Putting your baby to his cot/crib/ bed when he is sleepy before he falls asleep allows him to fall asleep quickly and eventually learn how to get himself to sleep.

• Wait a few minutes before

responding. When your baby wakes up and cries or fusses at night. Allow

your baby to try to fall back to sleep on his own first. If he continues to cry or fuss, check on him without turning on the lights, playing with, or picking him up. Consider if it is time for the next feed, if the nappies are soiled, or if the baby is uncomfortable for some other reason, including having a fever or being unwell. If these issues have been addressed and your baby continues to fuss or cry, you may try gentle rhythmic patting to settle him. Other settling options include patting the mattress or jiggling the cot/crib gently.

• Avoid stimulating your baby. When

feeding or changing your baby during the night, do so in a quiet and calm manner.

• Wrapping newborns snugly with

a thin baby blanket/cotton/muslin wrap during sleep may help them to sleep uninterrupted by reducing their startles and making them feel more secure. However, you should take care not to overheat your baby with the wrapping, check that the wrapping is not too tight, and that his breathing is not obstructed by the wrapping.

• Play and talk to your baby more

during the day, and expose him to comfortable light and sounds, to help to lengthen his awake time. Keep the environment quieter and dimmer with less activity as evening approaches to help your baby sleep longer periods during the night.

• Avoid night feedings after the age Wrap newborns snugly to help them sleep better.

of six months. Night feedings are not necessary from the physiological


point of view in healthy babies after the age of six months and may increase wetting and disturb sleep.

Behavioural Insomnia in Childhood Insomnia, which is the inability to initiate and/or maintain sleep does not only affect adults. Children can also suffer from insomnia, and the consequences of insomnia in children can affect both the child and the parents. There are many possible causes of insomnia in children. They include behavioural insomnia of childhood (which is discussed below), and other causes such as delayed sleep phase disorder (more common in adolescents due to the two-hour phase delay in their circadian rhythm mentioned earlier), medical conditions (e.g. obstructive sleep apnoea, medical conditions causing pain, itch or cough that disrupt sleep), psychological conditions (e.g. anxiety, depression, stress) and medications.


This section will discuss behavioural insomnia of childhood, which can be further classified into sleep onset association disorder, limitsetting sleep disorder, or combined disorder (combination of both sleep onset association and limit-setting disorder). If you suspect that your child has difficult-to-manage behavioural insomnia of childhood, or if your child has other causes for his insomnia, consult your doctor who will be able to help, or refer your child to a paediatric sleep specialist.

1. Sleep Onset Association Disorder A child with sleep onset association disorder relies on specific stimulation, objects or settings for initiation of sleep, or to return to sleep, following an awakening. Although there are no universally acceptable or unacceptable sleep associations, specific associations that are highly demanding, or disruptive to the caregivers are considered negative sleep onset associations (e.g. prolonged rocking, numerous episodes of feeding or nursing for age).

How common is it? Sleep onset association disorder is estimated to affect 25 per cent to 50

Have a good sleep routine with positive sleep associations.

per cent of children at 6 to 12 months of age, and 15 per cent to 20 per cent of toddlers. Sleep onset association disorder usually starts in infancy from 4 to 6 months of age. What to look out for The child with sleep onset association disorder often presents with frequent night awakening as he is unable to self-soothe back to sleep after a spontaneous night awakening. The child may get frustrated and cry without caregiver intervention to provide the association required to sleep. Persistent night awakenings are likely to continue for some time without intervention, although negative sleep associations developed during infancy tend to taper off with age depending on

the associations (e.g. use of pacifier until three to four years of age, parental help to fall asleep until seven to eight years of age). Risk Factors Factors that may increase the likelihood of night awakenings include breastfeeding, co-sleeping, colic, acute illness, changes in the sleep environment, difficult temperament, parental anxiety, and when the child has just achieved a certain motor or cognitive developmental milestones (e.g. pulling to stand, separation anxiety). Management Management of sleep onset association disorder includes establishing a good sleep routine which involves positive sleep associations. Good sleep practices stated earlier are important, and include setting a fixed bedtime daily, a relaxing and soothing routine before bedtime, leaving the child in the crib/ cot/bed drowsy but still awake, and an appropriate sleeping environment. Playing some light and soothing classical music in the background, and a comforting object (e.g. stuffed toy or used mother’s shirt) to act as a positive sleep association may help.


When getting your child to learn to fall asleep on his own, you may consider the following methods of response to the child. There is no ’best’ method to helping your child learn to fall asleep. It depends on factors such as your child’s temperament, your personality and tolerance for crying and fussing, your family routine and home situation, and your acceptance and expectations of the methods. Do note that whichever method you decide will work best in your situation, all caregivers must be consistent and adopt the same response. Usually once your child is able to fall asleep alone at bedtime, he is likely to learn to self-soothe to sleep during spontaneous night awakenings soon. 1. Extinction – Putting your child to bed at a fixed time and ignoring your child until a set time the next morning. This method is not recommended before six months of age. It may be emotionally draining, but usually takes three to four nights up to a week to be effective. Parents should be prepared for a ’post-extinction burst’ in some children.


2. Graduated extinction – Respond to your child briefly, but after progressively longer periods of time to allow him to learn to fall asleep independently (leave for 2 minutes, then return to reassure, then 5 minutes, then 10 minutes, and then every 15 minutes before returning to reassure until your child sleeps). This method is likely to take longer but is less emotionally taxing. 3. Fading of adult intervention – Establish a bedtime routine before sleep, and gradually increase the physical distance between you and your child while he is falling asleep (sit by the crib/cot/bed with little physical contact and night by night move the chair further away until out of sight of the child). This method is also likely to take longer but is less emotionally taxing. 2. Limit-Setting Sleep Disorder In limit-setting sleep disorder, inadequate enforcement of bedtime limits by parents result in the child delaying his bedtime or refusing to go to bed.

How common is it? Bedtime resistance is estimated to be present in 10 percent to 30 percent of preschoolers. About 15 percent of children 4 to 10 years old may still have significant limit-setting sleep issues. What to look out for Bedtime stalling behaviour manifests as attempts to delay bedtime (e.g. having parents read another book, give another hug, request for another drink, or to go to the toilet), based on what the child has learnt will elicit a response from the parent. Bedtime refusal behaviour manifests as refusal to get ready for bed, or refusal to stay in bed. Some children may indicate nighttime fears in order to stall bedtime. In some situations, the parents do not set appropriate limits or are inconsistent in their limit-setting (e.g. allowing the child to fall asleep while watching television, allowing the child to fall asleep on the parent’s bed). Other daytime behavioural problems and limitsetting difficulties may also be present in these children.

conflicting parental disciplinary styles and family tension. Management Management includes good sleep practices mentioned earlier, specifically setting a fixed bedtime, reviewing sleep schedules (e.g. avoid late afternoon naps in older children), and consistent parental limit-setting. You should aim to establish a set bedtime that coincides with the child’s natural sleep onset time. The method of ’bedtime fading’ may be practised, where the bedtime is initially set at the current bedtime, and brought forward gradually to the desired bedtime, to reduce struggles between bedtime and sleep onset.

Risk Factors Factors that increase the risk of limit-setting disorders include the child sharing the parent’s bedroom, Set clear and consistent bedtime rules for your child.


Clear bedtime rules need to be set with your child (e.g. staying in bed, not calling out for parents), and ignore complaints about bedtime (e.g. ’I am not tired’). Check on your child very briefly if needed, to provide reassurance and also to reinforce limits, and return your child to bed immediately if he gets out. You may also expect a transient worsening of behaviour in some children at the beginning of trying to set limits, before any significant improvement. All caregivers must be consistent and firm in their manner.

the child does not remember the event the next morning. They are thought to be associated with an immature neurological system, and tend to occur more frequently during episodes of acute illness and/or fever, stress, or in association with any disorder that disrupts sleep (e.g. obstructive sleep apnoea, medical conditions disrupting sleep). This section will focus on the parasomnias with more dramatic presentations – confusional arousal, sleep terror and sleepwalking. 1. Confusional Arousals

You may also consider positive reinforcement (e.g. sticker charts and small rewards) to help motivate your child.

Parasomnias In Children Parasomnias are unpleasant or undesirable events that intrude into sleep. The common parasomnias in children are nightmare disorder, confusional arousal, sleep terror, sleeptalking and sleepwalking. With the exception of nightmare disorder, these parasomnias usually occur within the first three hours after sleep onset and


Confusional arousal consists of confused behaviour during and following arousals from sleep (typically from a sleep stage known as slow wave sleep in the first third of the night), and also upon attempted awakening from sleep in the morning. How common is it? Confusional arousal is present in 5 percent to 15 percent of children and is usually benign in nature. It usually starts before five years of age and peaks in frequency during mid-childhood before spontaneous remission. There is usually

a history of confusional arousal in family members of children who have this condition. What to look out for Episodes of confusional arousal are usually sudden and may be startling. They can sometimes be brought on by forced awakenings. The child may appear to be awake but is disorientated to time and space, and will be slow in speech and mentation, responding poorly to commands. The child may sit up in bed, moan or whimper inconsolably, and say words like ‘Go away!’ , ‘No!’ or may exhibit even more bizarre behaviour like talking to a lamp. The episode usually lasts for a few minutes to half an hour, sometimes longer. 2. Sleepwalking (Somnambulism) Sleepwalking consists of a series of complex behaviours. It is usually initiated during arousal from sleep (slow wave sleep during the first third or half of the night) and culminates in

walking around with an altered state of consciousness and impaired judgement. How common is it? The onset of sleepwalking is usually between four to six years of age. About 15 percent to 40 percent of children have sleepwalked on at least one occasion, with 3 percent to 4 percent having frequent (weekly or monthly) episodes. Episodes usually decrease during adolescence. In children who sleepwalk, a third of them continue to sleepwalk for 5 years, while 12 percent continue to do so for 10 years. There may be a family history of sleepwalking in children who sleepwalk. What to look out for Episodes of sleepwalking usually begin with the child sitting up in bed and looking around confused, before walking. It can involve routine behaviours (e.g. unlocking the door) or more inappropriate behaviour (e.g. urinating into a waste paper basket). The child may sometimes speak, but the speech is usually meaningless. The child usually appears to be awake with the


eyes open with a confused ‘glassy’ stare. The child may then return to sleep on his bed, or lie down at an inappropriate site to sleep. The child is usually very difficult to arouse during an episode of sleepwalking, and will appear confused and disorientated if awoken. 3. Sleep Terrors (Night Terrors) Sleep terror is characterised by a sudden arousal from sleep (slow wave sleep) with a piercing cry accompanied by physical symptoms and behavioural manifestations of intense fear.

What to look out for The event is often of sudden onset. The child sits up in bed and screams in fear, looking tense with symptoms of flushing, sweating, fast breathing and increased heart rate. The child is often inconsolable and attempts to do so may worsen the reaction. If awoken, the child will appear disorientated and confused. Episodes usually last only for a few to five minutes, with the child returning to sleep on his own thereafter.

How common is it? Typical onset of sleep terror is between two to four years of age and tends to decrease in frequency as the child grows older. It rarely persists beyond puberty. Usually more males than females are affected, and a history of sleep terrors in family members may be present. It is estimated to affect three per cent of prepubertal children, and one per cent of adults.

Mild cases of parasomnias are often benign and self-limiting.


Night terrors may be confused with another more common parasomnia – nightmare disorder. In contrast to night terrors, the physical symptoms and behavioural manifestations in nightmares are usually much less intense and dramatic. Nightmares tend to occur in the last third of the night (during a sleep stage known as rapid eye movement sleep). If awoken, the child is able to recall events vividly during a nightmare and will be orientated, in contrast to a night terror.

Management of Parasomnias The management of parasomnias as a group in children is usually conservative. In mild cases, reassurance and education of the child and parents on the benign and self-limited nature of the condition will suffice.

You should maintain good sleep hygiene and practices, specifically a consistent bedtime routine and schedule for your child. Interventions to prevent physical injuries will be important in sleepwalking (e.g. gates at the top of the stairway, locking of windows and the main door). During the event, you should guide your child to the bed without waking him. You should not try to wake your child during the episode, or discuss the events with your child the next day as this is generally not of much help. In children in which episodes are predictably recurrent, a scheduled awakening just before the usual time of the first episode on a nightly basis for a few weeks may be effective. If there are underlying triggers that are causing arousals leading to the parasomnias (e.g. environmental noise,

Maintain good sleep hygiene and practices to help manage parasomnias. 67

obstructive sleep apnoea, periodic leg movement disorder), these should be avoided or treated. Medications are rarely needed.

Obstructive Sleep Apnoea in Children Obstruction sleep apnoea is a condition where there is recurrent intermittent obstruction (complete or partial) of the upper airway during sleep, leading to reduced airflow to the lungs and sleep disruption. Obstructive sleep apnoea can affect both adults and children, but there are some differences in the cause and management of this condition between adults and children.

snoring. About one percent to three percent of children have snoring with obstructive sleep apnoea. Boys and girls are equally affected in contrast to adults, where more men than women have obstructive sleep apnoea. The peak age is between four to seven years of age, usually in children with enlarged tonsils and/or adenoids. With increasing obesity in children, there is a second peak seen in older children above eight years old. The risk of obstructive sleep apnoea in obese children increases significantly, with 13 percent to 66 percent of obese children having the condition.

Habitual or persistent snoring is an important symptom of obstructive sleep apnoea, but not all children with snoring will have obstructive sleep apnoea. Children with habitual snoring but no evidence of compromised breathing and sleep disruption have ’primary snoring’.

Causes The two most important causes of obstructive sleep apnoea in children are enlarged tonsils and/or adenoids (often in atopic children who have allergic rhinitis), and obesity. Some children may have both adenotonsillar hypertrophy and obesity contributing to their obstructive sleep apnoea.

How common is it? It is estimated that overall, 3 percent to 12 per cent of children have habitual

Risk factors Other groups of children at risk for obstructive sleep apnoea include


children with neuromuscular (central nervous system and muscle) disorders, abnormality in the jaw and/or face, Trisomy 21 (Down syndrome), and those with a family history of sleep and breathing disorders. What to look out for Some of the symptoms suggestive of obstructive sleep apnoea that parents should watch out for in snoring children are: • Loud and frequent snoring • Cyanosis (bluish or purplish discoloration of the lips, nail beds or skin) or apnoea (transient cessation of breathing) during sleep • Snorting, gasping associated with snoring during sleep • Laboured breathing during sleep, with ‘sucking in of the chest’ • Unusual sleeping position, such as hyperextending the neck to breathe better, sitting up, propped with many pillows • Restlessness and frequent awakening during sleep • Diaphoresis (profuse perspiration) during sleep • Mouth breathing in the day or during sleep

• • • •

Difficulty getting up in the morning Unrefreshed after an overnight sleep Morning headaches Irritability, aggressiveness or simply ‘cranky’ • School or other behavioural problems • Falling asleep or daydreaming in school or at home Complications Some of the complications of untreated significant obstructive sleep apnoea include: • Learning and/or behavioural problems • Poor growth • Hypertension (high blood pressure) • Gastroesophageal reflux (backward flow of stomach contents into the food passage) • Insulin resistance and metabolic syndrome (a group of medical conditions associated with high blood pressure, heart disease and diabetes mellitus) • Death in very severe untreated cases (rare in most children)


Diagnosis Clinical history and physical examination are not sufficiently reliable to differentiate primary snoring from obstructive sleep apnoea. If your doctor suspects that your child has obstructive sleep apnoea, he will refer your child to a paediatric sleep specialist for review, and an overnight polysomnography (sleep study). Your child will be admitted overnight to a single room in a sleep laboratory, where his sleep and breathing parameters will be monitored and recorded continuously during sleep, to look for sleep disruption and evidence of laboured breathing or reduced airflow to the lungs during sleep. There will be sensors placed on your child’s head and body, and elastic bands placed around his chest and abdomen, connected by wires to a computer system that records the data collected. There will not be any pain, and most children will be able to fall asleep after they get used to the setup. One caregiver is allowed to stay overnight with the child during the study.


Treatment The treatment of obstructive sleep apnoea in children depends on the cause of the disorder. In children with enlarged tonsils and/ or adenoids causing the obstructive sleep apnoea, tonsillectomy and/or adenoidectomy (surgery to remove the tonsils and/or adenoids) often result in resolution of the obstructive sleep apnoea, unless there are other risk factors. Children with obstructive sleep apnoea where surgery is not an option (e.g. obesity as the sole cause of obstructive sleep apnoea, Trisomy 21 child without enlarged tonsils or adenoids), or children with significant residual obstructive sleep apnoea after surgery, may be managed with the use of continuous positive airway pressure (CPAP) during sleep. CPAP is administered to the child using a nasal/face mask connected by tubing to a machine device which is able to generate and deliver a positive pressure. The positive pressure helps to keep the upper airway of the child

open during sleep. Children who are treated with CPAP for their obstructive sleep apnoea will need a specialised overnight sleep study (CPAP titration polysomnography) to ascertain the optimum pressure needed to keep the airway open during sleep. They will also need to have regular titration studies, at least annually, to check if there is any change in the CPAP requirement. They will have to be managed by a paediatric sleep specialist.

Please refer to our booklet on ‘Up Close: Get the answers to common Ear, Nose and Throat Conditions’ for more details on surgical treatment, including adenotonsillectomy. (Section: Common ENT conditions among Children Snoring in Children and Tonsils & Adenoids) Respiratory Medicine Service KK Women’s and Children’s Hospital Tel: 6294 4050

Children with obesity as a sole or contributory cause of their obstructive sleep apnoea should lose weight as well. It is often not easy to lose weight, and in children and families with difficulty doing so on their own, they can be referred to paediatric specialists for weight management programmes. Besides the treatments mentioned above, some children with specific risk factors or causes for their sleep apnoea may benefit from orthodontic assessment and procedures, or other forms of surgery for their sleep apnoea.


Services available at SingHealth Institutions Singapore General Hospital Sleep Disorders Unit SGH Sleep Disorders Unit (SDU) is the largest and most complete sleep unit in Singapore. It is a multidisciplinary unit comprising of neurologists, respiratory physicians, ENT (Ear, Nose and Throat) surgeons, psychiatrists, psychologists, sleep technologists and respiratory therapists. It is also the first adult sleep unit in Singapore to achieve international accreditation by The Thoracic Society of Australia and New Zealand. We offer the most comprehensive range of inpatient and outpatient services for the evaluation, treatment and education of patients with sleep disorders in Singapore. Sleep disorders include sleep disordered breathing, obstructive sleep apnoea, snoring, obesity hypoventilation syndrome, parasomnias, nocturnal epilepsy, REM disorders, leg movements disorders and insomnia.


We comprise of a Sleep Disorders Clinic for outpatient consultation services and patient rooms for performing sleep studies. Our sleep studies are very thorough with measurements of brain waves, respiratory pattern and leg movements for example and are fully attended by sleep technologists. The following services are available: Sleep Study

• Overnight Diagnostic

Polysomnogram (PSG) or Overnight Sleep Study This is the most common type of sleep study, primarily used to diagnose sleep apnoea and parasomnia.

• Positive Airway Pressure (PAP)

Titration Sleep Study either Continuous Positive Airway Pressure (CPAP) or BiLevel Positive Airway Pressure (BIPAP) The sleep study is used to determine the necessary PAP pressure required to abolish the sleep apnoea and to determine effectiveness of PAP therapy.

• Multiple Sleep Latency Test

(MSLT)This test is used to aid in diagnosis of narcolepsy and to measure the severity of daytime sleepiness. It is performed in the day following an overnight diagnostic PSG.

• Maintenance of Wakefulness Test (MWT)

• Full EEG Overnight

Polysomnogram (PSG)

Outpatient Services

• Outpatient Consultation Clinic

Sleep physicians conduct a dedicated clinic for diagnosis, evaluation and treatment of sleep disorders.

• Positive Airway Pressure Therapy Services Education and counselling services regarding use of Positive Airway Pressure therapy.

• Cognitive Behavioral Therapy (CBT)/ Psychotherapy


Sleep Disorders Unit Dr Ong Thun How (Director) Senior Consultant Department of Respiratory and Critical Care Medicine A/Prof Pavanni Ratnagopal Senior Consultant Department of Neurology Dr Anne Hsu Senior Consultant Department of Respiratory and Critical Care Medicine A/Prof Ng Beng Yeong Head & Senior Consultant Department of Psychiatry Dr Tan Keng Leong Senior Consultant Department of Respiratory and Critical Care Medicine Dr Toh Song Tar Consultant Department of Otolaryngology (Ear, Nose & Throat) Dr W.S. Shahul Hameed Associate Consultant Department of Neurology


For enquiries, please contact: Tel: 6321 4377 Fax: 6224 9221

• We also partner family physicians

and paediatricians to facilitate the medical care and management of our patients at the community level.

KK Women’s and Children’s Hospital Respiratory Medicine A key referral centre in Singapore for breathing and sleep-related disorders, our Respiratory Medicine Service cares for a wide range of conditions offering newborns to 16-year-olds. We lead two national programmes:

• The National High Risk Asthma

Shared Care (NASC) programme, also known as Singapore National Asthma Programme (SNAP) • The evaluation of severely obese children with Obstructive Sleep Apnoea (OSA).

Range of Conditions: • General respiratory disorders • Asthma • Chronic/congenital lung diseases • Respiratory infections • Sleep-related breathing disorders • General sleep disorders Range of Services: • Pulmonary assessment. We have a complete pulmonary function laboratory that we can perform spirometry, lung volume, diffusion, exhaled nitric oxide, and bronchoprovocation studies. We also conduct cardiopulmonary exercise tests for children. • Skin allergy testing. This complements the evaluation of an atopic child with asthma. • Paediatric flexible bronchoscopy • Video polysomnography and mean sleep latency tests. Our Sleep Disorders Centre evaluates sleep


disorders ranging from sleep-related breathing disorders, parasomnias, hypersomnias, and periodic limb movement disorders. For enquiries, please contact: Tel: 6294 4050 Fax: 6293 7933

Senior Consultant Prof Chay Oh Moh Adj A/Prof Anne Goh Eng Neo* Consultant Dr Teoh Oon Hoe Head (Head)* Dr Arun Pugalenthi* Dr Biju Thomas* Dr Ho Ling Associate Consultant Dr Petrina Wong* *Accept referrals for sleep disorders


Acknowledgements Dr Ong Thun How Senior Consultant Department of Respiratory and Critical Care Medicine Director, Sleep Disorders Unit Singapore General Hospital Dr Toh Song Tar Consultant, Sleep Apnoea Service, Department of Otolaryngology (Ear, Nose & Throat) Consultant, Sleep Disorders Unit Singapore General Hospital Dr Tan Keng Leong Senior Consultant Department of Respiratory and Critical Care Medicine Singapore General Hospital A/Prof Ng Beng Yeong Head & Senior Consultant Department of Psychiatry Singapore General Hospital A/Prof Pavanni Ratnagopal Senior Consultant Department of Neurology Singapore General Hospital

Dr Victor Kwok Associate Consultant Department of Psychiatry Singapore General Hospital Dr Wong Sheau Hwa Associate Consultant Department of Psychiatry Singapore General Hospital A/Prof Anne Goh

Head and Consultant Allergy Service Department of Paediatric Medicine KK Women’s and Children’s Hospital Dr Teoh Oon Hoe Head and Consultant

Respiratory Medicine Service Department of Paediatric Medicine KK Women’s and Children’s Hospital Dr Petrina Wong Associate Consultant

Respiratory Medicine Service Department of Paediatric Medicine KK Women’s and Children’s Hospital

Published by the Marketing Communications and Partnership Development Dept, SingHealth






80 Tel: (65) 6225 0488 Fax: (65) 6557 2138 Singapore Health Services Pte Ltd 31 Third Hospital Avenue #03-03 Bowyer Block C Singapore 168753 For enquiries, your GP/family doctor or contact us at: For enquiries, consultconsult your GP/family doctor or contact us at:

Tel: (65) 6321 4377

Tel: (65) 6294 4050

Tel: (65) 6436 8088

Tel: (65) 6436 7840

6324 8802

Tel: (65) 6357 7095

Community Hospital

6227 7266

Partner in Academic Medicine

For international enquiries: 24-hr Hotline: (65) 6326 5656 Fax: (65) 6326 5900 Email:

Tertiary Hospitals Information correct as at January 2013. Reg. No.: 200002698Z

Sleep Matters: Get the answers to common sleep conditions  

In the last 20 years, we are understanding far more about sleep and more importantly, are better equipped to diagnose and treat sleep condit...

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