CAN YOU HEAR IN YOUR SLEEP?

It’s believed that humans spend about a third of their lives asleep. However, everyone sleeps differently—some wake up at the tiniest amount of noise, while others can sleep through just about anything. That might lead you to wonder: Can people hear in their sleep?

The short answer is yes. It’s totally normal to hear while you’re asleep, since the brain stays active at night. Some areas are more active than others depending on the sleep stage, but generally speaking, the ear continues to pick up sounds. The brain then decides whether or not to react to the stimuli. In one study by a team of French researchers, participants were conditioned to press a button with their right hand if they heard the name of an animal and their left hand if they heard the name of an object. The researchers then played different words to the subjects while they were asleep. When they analyzed the responses of the subjects’ brains, they found that the areas that controlled the movements of the appropriate hands were activating. This shows that we not only hear when we’re asleep— we analyze what we’re hearing.

Understanding Sleep Phases

While we do process sounds, how much we react depends on what sleep phase we’re in. A sleep cycle consists of two phases: slow-wave sleep and REM sleep. The first phase begins with the light sleep stage, which lasts just a few minutes. In this stage, breathing slows down and muscles relax. We’re also the most sensitive to sound—the slightest noise can alert us and wake us up. Next comes light slow-wave sleep, which makes up around 50% of our rest. Sounds can still wake us up pretty easily at this point. The last stage of slow-wave sleep, deep slow-wave sleep, makes up another 25% of our rest. Brain activity is slowest during this stage, and it’s when we recover the most physically. This is when it’s hardest for noises to rouse us from sleep. Finally, we enter into the phase of REM sleep. It’s a paradoxical phase when signs of very deep sleep combine with signs of wakefulness. We experience intense brain activity; this is typically when we have the most dreams. REM sleep accounts for around 25% of our total rest, and it’s when our reaction to sounds varies the most. In total, the sleep cycle lasts 90 minutes and we go through 3 to 5 cycles a night.

Sleeping Better

People who wake up easily at night tend to feel like they’re having a lighter sleep. However, they’re more likely being disturbed during light slow-wave sleep, when their senses are still awake. This prevents them from moving on to the next sleep stage and getting a good night’s sleep. Thankfully, there are ways to make sure you’re going through the whole sleep cycle. First of all, make sure your room is dark and quiet to prevent light and noise from disrupting your sleep. If you can’t control an outside source of noise, you can use custom-made sleep earmolds to silence it. You can also encourage sleep by trying to limit your screen time for at least an hour before you go to bed. Finally, if you avoid CUSTOM-MADE eating before bed, you’ll make sure your digestive system isn’t working during the night. SLEEP EARMOLDS Seeing as our auditory system is always active and our brain can process sound even when we’re asleep, it’s no surprise that some people are light sleepers! If you have any questions about custom-made sleep earmolds, don’t hesitate to contact an audioprosthetist.

Lou-Ann Leblanc

Audioprosthetist practicing in Neufchâtel and Sainte-Anne-de-Beaupré

References - Koudier, Sid, et al., Inducing Task-Relevant Responses to Speech in the Sleeping Brain, Volume 24, Number 18, September 22, 2014, pp. 2208-2214. Online. https://www.sciencedirect.com/science/article/pii/

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