NOTESONTHETHIRDEDITION
AsIwrotethisthirdedition,Iwasoftenasked,“Whywriteanothereditionofthisbookwhenthecontent willbecomeinstantlyobsolete?’Althoughitistruethattechnologyisconstantlyinastateofmotion,thereare manyreasonswhyIdedicatedmanyhourstowardthisbookupdate Hereareafew:
• Peopleneedhelp. Many families and educational professionals are unable to keep up with technological changes and are realizing that they don’t even know where to begin to figure out appropriate affordable solutions
•Priorsolutionsmaynolongerwork. It’s only been 4 years since I wrote the second edition of this book, butquitealothaschanged!Unfortunately,manyhigh-qualityappsarenolongeravailable.Olderdevices andapps,whichworkedwellinthepast,maynolongerworkonnewoperatingsystems Individualswho havespecialneedsorwhosupportothersoftenfindthemselvesseekingnewsolutions
•Manyfeaturesthatwerecostlyinthepastarenowfreeandreadilyavailable. Quite a few products that I featured in prior versions of this book are now included on the devices we already own, but people may notknowtheyexistorthinktousethem
•Thereistoomuchtodointoolittletime.Educationalfundingcutsandhealthreimbursementwoeshave made it increasingly difficult for families to obtain help from qualified specialists Families are often the ones who need to take the initiative to explore options for their children My hope is that this book will helpfamiliesaswellasprofessionalssavetimewhensearchingforworkablesolutions.
•Technologyhasimproved Many apps, devices, and online resources have withstood the test of time and have dramatically improved over the years With a bit of help getting started, the user experience is generallymorepositiveandhelpfulthaninthepast.
•Moreonlinesupportisavailable It is now much easier for families and educators to learn from others in similar situations Video tutorials that speed up the learning curve are readily available online, and families, educators, and product developers are connected online and support each other once they know wheretolook
It’shardtolearnmoreaboutfeaturesandappsyoumaynotevenrealizeexist Mymissionistocontinueto expose readers to state-of-the-art, affordable, effective, research-based solutions that can improve the quality of life of people with communication, literacy, learning, or cognitive challenges. These are exciting times, as our society continues to experience monumental changes in the many ways technology can help people with disabilities.
Unfortunately,withthegoodcomesthebad.Thenegativeconsequencesoftechnology’susearealloverthe media: excessive screen time can cause problems; Internet access can be dangerous; technology addiction can ruin lives; brain function may be affected. We need to be wise consumers and maximize the benefits of technology while minimizing the harm that it can cause. It’s all about how we use technology and safety comesfirst Weneedtoprotectthosewelovefromtheharmtechnologycancausewhileexposingthemtothe
potentialbenefits
Many families realize that there is much to learn, and they may find it difficult to access appropriate informationthatisnottootechnicaloroverwhelming.Speech-languagepathologists,occupationaltherapists, tutors,specialeducationteachers,administrators,andfamilymembershaveincreasinglyembracedtheconcept of using technology and often have access to mobile devices, but many may find it difficult to keep up with changes. In my experience, proactive families are often frustrated and left on their own to figure out how technologycanbeusedeffectivelytomaximizethebenefitstotheirlovedonesofallagesathome.
Pleaseusetheresourcespresentedinthisbookasastartingpointfromwhichtolearnmore Checkoutthe organizations, bloggers, app developers, vendors, and websites listed. This guide is not intended to prescribe assessment or treatment protocols for students. The information should not be used to replace professional evaluation,collaboration,andservices
Hopefully, this guide will speed up the learning curve to help professionals as well as family members identify helpful ways to zero in on the tools and resources they need. Skilled intervention is needed for students who struggle to communicate, read, write, and learn Those who decide to integrate technology to improve the outcomes of education, therapy, and parenting efforts must expect to invest time and effort into exploringandtryingtheresourcestolearnwhichonesarebestfortheirsituations.
Please keep in mind that, when providing direct services in my private speech therapy practice, I use many strategies and approaches that do not involve technology Although this book is primarily focused on technology tools, skilled therapists and teachers need to keep in mind that technology does not replace their expertise Tools do not replace people, but they can be very engaging and fun, as well as produce amazing outcomesifusedjudiciously
If you would like to continue to receive guidance from me on my top picks for technologies to help students, please connect with me through my website at https://wwwinnovativespeechcom I regularly post information on my website and a variety of social media sites about upcoming workshops and online mini video courses that you can watch at a time and place that suite your learning and lifestyle. Feel free to e-mail me at Joan@innovativespeechcom or call 301-602-2899 or 1-800-IST-2550 if you would like to discuss your situationandhowImightbeabletohelpyou
GETTINGSTARTEDWITHASSISTIVETECHNOLOGY
IMPROVINGTECHNOLOGIESOFFERHOPE
Do you own a laptop, tablet, or smartphone? If you said “ yes, ’ you are in good company. Access to computersandonlineresourceshasbecomeanintegralpartofourdailylives AccordingtothePewResearch Center(2018),95%ofAmericanadultsownacellphoneofsomekind.Inaddition,about80%ownadesktop or laptop computer, roughly half own a tablet computer, and 20% own an e-reader. The great majority of households have high-speed Internet access, and schools are embracing technologies more than in the past Features that used to cost many hundreds of dollars, such as touchscreens and reading and writing supports like text-to-speech and dictation, are now features included in the phones, tablets, computers, and browsers wealreadyuse
As the affordability and availability of educational and personal technology tools increase, so does the potential for greater success and independence for people who have communication, learning, and cognitive challenges Teachers, therapists, and families need to embrace and adapt to technology to empower individuals with special needs. Unfortunately, many of the people who could benefit the most from these recent advances remain in paper-based worlds receiving services that do not take advantage of effective new technology tools to support literacy, communication, and learning Many individuals with disabilities are never exposed to new affordable products that could help them succeed in life. As our society becomes increasinglydependentontechnologiesforcommunicationandinformationaccess,peoplewithdisabilitiesare experiencing an ever-increasing digital divide Everyone deserves to be exposed to mainstream, as well as specialized,easy-to-useresourceswithwhichheorshecanaccomplisheverydaytaskswithincreasedeaseand efficiency. The world of technology has become much more affordable many state-of-the-art resources are nowreadilyavailableand,whenusedproperly,canhaveaprofoundpositiveimpactonthelivesofindividuals with autism spectrum disorders (ASD), learning differences, communication challenges, cognitive deficits, anddevelopmentaldisabilities.
WHATISASSISTIVETECHNOLOGY?
Assistive technology devices (also referred to as adaptivetechnology) refer to any “item, piece of equipment, or product system, whether acquired commercially, modified, or customized, that is used to increase, maintain, or improve functional capabilities of individuals with disabilities’ (Assistive Technology Act of 2004, § 3.4). Assistive technologies can remove barriers to independence and success, especially when used in the individual’s natural setting, such as the home, school, or workplace. These tools can reduce the burden of difficultskillsandenhanceindependenceduringdailylifeatschool,work,andhome,andinthecommunity
In this book, I highlight a wide range of technologies, many more than what typically come to mind for most of us when we hear the words assistive technology. I truly believe that the apps, features, websites, and additionalinformationincludedinthisbook,whenusedwithanindividualwithspecialneeds,mayallowthat
individualtoachieveresultsthatheorshecouldnothavegainedwithoutthem.Itistruethatmostindividuals will be able to improve outcomes and maximize success with the help of many of the cutting-edge mobile features and apps I have carefully selected. However, it is also true that individuals with special needs who learnandcommunicatedifferentlymayrequirethemtomaximizetheirtruepotentialandhappiness.
HELPFULTECHNOLOGIESALLAROUNDUS
Technology has slowly crept into our lives, and it is here to stay, for better or for worse Many families, educators, and therapists tried early on to use new devices and products, only to become frustrated and overwhelmed Many efforts were abandoned Thankfully, computers and mobile devices, along with their features and associated apps, have continued to improve and have become more reliable, user-friendly, and affordable. Although considerable concern remains over how to use technology safely to minimize the negative consequences for our children, the use of assistive technology is gaining increased acceptance in the deliveryofservicesinschool,therapypractices,andrehabilitationcenters
Schools,healthcaresystems,andvocationalsettingsarestrugglingtobalancethedeliveryofqualityservices with increasing costs and regulations With the use of the assistive technologies highlighted in this guide, readers become empowered with the ability to contain costs, adhere to stringent regulations, and effectively help people of all ages with a wide range of communication, learning, and cognitive challenges. The key is to makeagoodmatchbetweentheindividualandthetechnologybeingused
Theworldsofassistivetechnology,educationaltechnology,andmainstreamtechnologycontinuetomerge Changeishappeningsofastthatitisdifficulttostayontopofthemanynewwaystechnologycanbeusedto help people of all ages who have subtle or debilitating challenges This guide will introduce you to, or expand your knowledge of, the exciting world of assistive technology one that includes many products and approaches that you may not know exist, as well as many you may be familiar with but have not thought to use,tohelpimprovespeaking,reading,writing,listening,thinking,memory,orlearning
TAKINGTHEFIRSTSTEPS
Whether you are a parent of a child with communication, learning, or attention challenges; a teacher or therapist trying to offer the best help you can for those to whom you provide services; or someone exploring thistopictohelpyourself,thekeystosuccessinusingthisguidearethesame:
•Startgradually
•Focusonthesectionswithinchaptersthatwillmeetyourimmediateneedsfirst.
•Starttonetworkwithothersinsimilarsituationsbyjoiningonlinesupportanddiscussiongroups
• Explore the websites of products that seem relevant to your situation to make sure that you learn about themostrecentspecifications,features,andpricesoftheproducts.
•Tryoutthemanyfreeresourcesandonlinesourcesforsupportthatmayhelp
•Becreativeandtrynewthings Thereisnoonecorrectwaytoproceed
SEEKINGPROFESSIONALGUIDANCE
This book does not replace the need for skilled professional intervention Professionals such as speechlanguage pathologists are trained to help people with communication and cognitive challenges; laptops,
tablets,andsmartphonesaremerelytoolstofurtherthathelp.Usersofthetechnologyneedtoremainfocused on their goals and work to achieve the desired outcomes Once a good match with the user and product is made, the selected resource should be configured or used in the best way to maximize progress toward goals. Someactivitiesmaybeenjoyablebutaren’teffectivetowardlearningnewskills.Peoplelearnindifferentways andarehelpedbydifferentstrategiesandtypesofassistance Oneproductcanbeusedinmanyways Figuring out the most effective approach to use the technology is critical for success. Also, it is important to keep in mind that the most recent tools aren’t always the best. Many years of research have been devoted to the field of assistive technology, and some of the dedicated communication systems and products that have been availableforalongtimemaybebetterthannewerproductsdevelopedformobiletechnologies.Therearepros andconstomostproducts,andthekeyisfiguringoutthebestfitforyoursituation.
HOWTOGETHELP
Onceyouselectthedevice,application,browser,feature,orsuggestedwebsitethatispotentiallyhelpfulfor youinyoursetting,spendsometimeexploringonlineresourcestoconnectwithotherswhomaybeinsimilar situations,orsearchonlineforreviewsorvideotutorials Bloggers,Facebookgroups,andreviewsitesareoften very helpful Be careful, however, about giving too much credibility to one disgruntled user who leaves a bad review. It’s hard to know the true reason that someone had a bad experience. YouTube (https://wwwyoutubecom) also often has helpful videos to watch, and I’ve shared some of my favorite YouTube channels and videos throughout the book Unfortunately, with the advent of less expensive mainstream mobile solutions, as opposed to more expensive software downloads or “special’ expensive equipment, it can be difficult to speak to customer support when there are problems A visit to the Apple Storetoaskaboutanon-ApplefeatureoranapponaniPadwillundoubtedlyendinfrustration
Onegoalofthisbookistohelpyoufindresourcessothatyoucanconnectonlineandlearnfromothersin similar situations who may have already found workable solutions to the issues you face For every resource highlightedinthisbook,therearemanythatIchosenottoinclude Thiscuratedlistwillhopefullyminimize your angst and propel you forward with positive experiences. In addition, I have a selection of online video coursesavailableforthepublicsothatyouwillbeabletoreceiveevenmorehelpfulinformationandguidance tailored to the needs of families and professionals who want to help an individual with communication, cognitive,literacy,andlearningchallenges.
WHATSOLUTIONIS“BEST”?
Ifrequentlygetaskedthefollowingtypesofquestions:
•Whichdeviceisbesttousetohelpmysonwithdyslexia?
•WhatshouldItryifmydaughteris3andhasn’tstartedtalkingyet?
• Which technologies are best to support my son who is disorgannized and about to start his first year of college?
• My student with ASD and who is nonverbal doesn’t appear to be motivated to communicate. What app shouldItry?
•Whichaugmentativeandalternativecommunication(AAC)appordeviceismosteffective?
Successful solutions require careful thought as well as trial and error. I have attempted to list my top picks in a variety of categories to help you in the quest for the “best” solution for your set of circumstances Please keep in mind that technologies are just tools that can be used to assist in the education and intervention process.Everypersonhasadifferentsetofstrengths,weaknesses,interests,andmotivations,aswellasunique environments, tasks, and people helping him or her You also will undoubtedly mix a bit of your own unique personalityintotheprocessasyoutrytohelpothers.Thereareoftenseveralpathstosuccess.
I have done my best to include updated suggestions and helpful resources for support and information throughout this guide so that you can benefit from all that I have learned The final chapter of this book includes a list of the resources that I have relied on the most as I navigate the “best” cutting-edge technology toolstosharewithfamilies,colleagues,andschools.
CHANGINGTECHNOLOGYTRENDS
Remember the days when sidewalks only had curbs, doorways weren’t wide enough for wheelchairs, and youcouldn’tpushabuttontoopenadoor?Althoughwestillseeplentyofcurbs,narrowdoorways,andheavy doors, which place barriers to people with physical disabilities, most new buildings are constructed with these universal accommodations in mind. People pushing strollers and carrying groceries appreciate the changes. These changes came to be because they helped everyone, not just people with disabilities In the same way, as technologybecomesmorepowerful,lessexpensive,andmoreportable,thebrowsers,devices,andappsweuse are adding features that are increasingly helpful for people who have experienced barriers to reading, writing, speaking, and learning By creating opportunities as well as removing performance barriers, technology can helppeopleofallagesandabilitiesexplorenewpossibilities.
There is now a growing emphasis on creating technologies that include features that are helpful for all learners, with and without “special needs” There is a push toward a universal design for learning (UDL), a concept created by the Center for Applied Special Technology (http://www.cast.org). In the world of educational technology, there is an emphasis on helping teachers learn to modify instruction and helping students find alternate methods to demonstrate what they know If you are interested in learning more about UDL,takealookatthesefreeresourcesthatprovideawealthofinformation:
•CASTProfessionalLearning:UDLResources(http://castprofessionallearning.org)
•FreeTechnologyToolkitforUDLinAllClassrooms(https://udltechtoolkitwikispacescom):Thissiteis managedbyKarenJanowski,anassistiveandeducationaltechnologyconsultant
•UDLTechnology:TechnologyforUniversalDesignforLearningandSpecialEducationbyJohnF.O’Sullivan: ThisbookcanbedownloadedandreadiniBooksonaMacoriOSdeviceforfree
REMAININGBARRIERSTOTECHNOLOGY
Despite recent advances in the more accessible features of mobile technologies, obstacles persist for individuals who have cognitive, communication, and access issues Even when materials are converted into a digitalformat,theymayremaininaccessible.
Itmaybedifficultforindividualswithcommunicationandcognitivechallengesto:
•providecomputerinputbymovingamouseortypingonthekeyboard;
•useasmallmobiledevice;
•readandinterpretinformationonascreen;
•sequenceandanalyzeproceduresneededtouseapps;
•usee-mail,texting,orsocialmediasitestoobtaininformationandinteractwithothers;and/or
•searchonlineforinformation.
Appropriatelyselectedassistivetechnologiescan:
•savetime;
•motivateandengageusers;
•maketaskseasierandmoreenjoyable;
•havereal-lifevalue;
•supportuniquelearningstyles,abilities,andbackgrounds;
•providefeatureflexibilityandcustomizabilityatalevelpreviouslyimpossible;
•facilitatepositiveoutcomesbycarefullycontrollingtasks;
•giveindependent,nonjudgmental,immediatefeedback;
•promoteeffectiveindependentpractice;
•streamlinedataandinformationcollection;
•enableuserstocreate,store,andaccessdocumentsandresourcesfrommultiplelocations;
•provideopportunitiestoobjectivelydocumentchangeovertime;
•increaseopportunitiesforsocializationandreduceisolation;
•enhancelifelonglearning;
•providemoreeffectivestudyingandlearningstrategies;and
•empoweruserstocollaborateonline
WHOCANBENEFITFROMASSISTIVETECHNOLOGY?
Devices, apps, and features have been developed to help people confronted with a wide variety of challenges People who are appropriate candidates for learning support from technology may have the following:
•developmentaldelays;
•attentionissues;
•ASD;
•executivefunctioningchallenges(scheduling,planning,followingthrough);
•readingandwritingdeficits(dyslexia,dysgraphia,arthritis,lowvision);
•languageandlearningdifferences;
•social,emotional,andbehavioralchallenges;
•verbalapraxia;
•intellectualandcognitiveimpairments;
•poorperformanceinschool;
•work-relatedchallenges;
•unintelligiblespeech(dysarthria);
•dysfluentspeech(stuttering);
•difficultylearningEnglishasasecondlanguage;
•avoicedisorder;
•ahearingimpairment;
•lackofinterestormotivationinschool-relatedactivities;
•aheadinjury(tumor,rupturedaneurysm,concussion,traumaticbraininjury,gunshotwound);
•aseizuredisorder;or
•socialthinkingchallenges
FAMILYADVOCACY
Often the family members of students with complex communication needs and learning differences take the initiative to learn more about educational methods and treatment options They expect their teachers, occupational therapists, speech-language pathologists, reading specialists, and tutors to use state-of-the-art tools and strategies. However, special educators and therapists typically don’t have the luxury of time and effective training to support this transition Parents confront their children’s struggles every day and are very motivated to seek alternative solutions to maximize school success and self-esteem Teachers and administrators want to do their best to help each student access the curriculum, but they confront many challenges when implementing assistive technologies and mobile solutions It is an enormous challenge to integrate new technologies into a system that is already confronted with many regulations and challenges This is a time of enormous conflict between families wanting to offer their children the newest assistive technology tools and schools constrained by limited budgets, lack of time, and few trained staff to implement thenecessarychanges
This guide streamlines the learning process, making it less daunting for families, therapists, teachers, and other professionals to learn about ways to help students who struggle academically Families, educators, and clinicians who are willing to collaborate and explore what these new tools can do in solution-focused sessions to supplement other techniques can achieve excellent results. Incorporating affordable technology into education and vocational training is well worth the effort, time, motivation, and dedication it requires This guide highlights software, hardware, and other resources that are versatile and therapeutically and educationallybeneficial.
TECHNOLOGYCHANGESWILLCONTINUE
It’s hard to predict the future of technology, but one expectation is certain: Technology will continue to change The items included in this guide are not an exhaustive list of instructional tools and strategies, but rather an updated representative sampling of products available on the market and some suggestions about how to use them It is inevitable that more products will become available and that the items described will change Newandimprovedfeaturesaremadeavailableallofthetime
I suggest that you use the information included in this book as a guide for learning more about how assistive technology can help you in your situation It can be frustrating when you finally adjust to using a deviceorappandthenthingschange It’sastruggletoadapt,butwellworththeeffort
ACCESSINGFEATURESINDEVICESYOUALREADYUSE
In life, most meaningful change is the result of hard work and effort that happens slowly over time Thankfully,that’snotalwaysthecase Hereareafewcompensatorysolutionsthatmaybeofhelpnow:
• Reading Comprehension: Text-to-speech features that read aloud the words on a screen can provide instant support for individuals who understand well but can’t read Digital text can be read aloud, highlighted,andenlargedtoimprovereadingcomprehensionandretention Studentsmaythenbeableto
betterunderstandaschoolassignmentorreadatextmessagefromafriend.
• Writing: Speech-recognition features can help those who have difficulty writing Speech recognition enablesindividualswithrelativelyclearspeechandintactcognitiontotalkandhavethecomputer,tablet, orsmartphoneautomaticallytranslatethespeechintowrittenwords.
•CloudStorage:AccountswithGoogle,Apple,Microsoft,orDropboxenablestudentstostoredocuments online. Gone are the days when students forgot to bring a document to home or school. Some of the servicesautomaticallysavethedocumentssothattheyaren’tinadvertentlylostwhenaccessissharedwith others
• Organization: Digital calendars, reminders, and to-do lists can be kept on all devices and synced to provide constant access in order to help people who have problems keeping track of daily activities and havepoortimemanagementskills
•Recording:Adigitalpenor appcanrecordaudioasapersonwrites, toassist withrecallofalecturefor a student who has trouble taking notes in class or to process the information as the student pays attention in class The student can later listen to the recording by accessing the audio that corresponds to specific pointsinhisorherwrittennotes.
• Speaking: Augmentative and alternative communication (AAC) apps can empower people of all ages whocan’tspeaktoselectpicturesorwordsandhaveadevicespeakforthem Manyoftheseproductscan be customized to meet the needs of the user, and many offer a dynamic display so that people can find whattheyaretryingtocommunicatewithacoupleofclicks.
•EnlargingText: iOS devices now can use the camera to magnify items in view, which is very helpful for individuals with low vision Some apps will then read the text aloud Accessibility features of all devices canempoweruserstoenlargethefontandoftendeclutterdocumentsandwebpagesforeasierreadingand morefocus
LIFTINGTHEBARRIERS: TECHNOLOGYANDACCESS
Technologycanprovideanewworldofindependenceforindividualswithspecialneeds Forthosewhoare unable to access the curriculum at school or complete a job in a vocational program, a product created for mainstream society or a customizable assistive technology tool created for the purpose of enabling increased access maybejustwhattheyneed
EASEOFACCESS
One of the first steps when using technology is to determine which method of access is the most appropriate For individuals with physical and cognitive limitations, it is often difficult to use computers, tablets,andmobilephoneswiththesameeaseastherestofsociety Theseindividualsmayhavedifficultywith vision,dexterity,language,orlearningnewprocedures.Itisoftenimportanttotryavarietyofdevices,screens, monitors,keyboards,styluses,mice,gestures,keyguards,andswitchestodeterminethebestaccessmethodfor each person I encourage professionals as well as family members to explore the accessibility features and options of devices, apps, and software, as well as peripherals such as keyboards and switches, in order to best matchtheperson’sneedswithavailabletechnologies
Easy-to-implementaccessibilityfeaturesareoftennowincludedaspartoftheoperatingsystemsofdevices Text can be read aloud and enlarged on computers, tablets, smartphones, and browsers. People with clear speech can speak and have words typed automatically More of these features are discussed throughout this guide
When an individual has multiple physical issues and may benefit from help with positioning, adapted switches, or other complex access issues, a multidisciplinary assistive technology team is ideal to establish the best method of computer access Depending on the needs of the individual, it may be wise to include an occupational therapist, physical therapist, vision specialist, audiologist, or behavior management specialist (typically a psychologist) on the assistive technology (AT) team to play an active role A comprehensive evaluation should be performed with input from the members of an educational, rehabilitation, or vocational team. Once the individual has the appropriate physical setup, a strategy can be developed for the use of technology to improve and compensate for communication, cognitive, literacy, and community-based challenges
GUIDANCEFORCOMPUTERACCESSANDASSISTIVETECHNOLOGIES
Several helpful online articles and protocols are available to assist with determining the most appropriate wayforanindividualtoaccesstechnology Twosuchwebsitesarelistedbelow
The SETT Framework: Critical Areas to Consider When Making Informed Assistive Technology DecisionsbyJoyZabala
http://www.joyzabala.com
• The SETT Framework is a free tool that helps guide the decision-making process for technology by focusingthedecisionmakersonthestudent,theenvironment,thetasks,andthetools.
• It was produced to assist teams through a variety of activities needed to help students select, acquire, anduseassistivetechnologydevicesandsoftware
WATI(TheWisconsinAssistiveTechnologyInitiative)
http://www.wati.org
• WATI is an incredible resource After formal funding for this statewide project ended, a group of AT consultantsvolunteeredtheirtimetoupdatethematerials,whichprovideawealthofinformation
• In 2017, WATI made available an updated package of materials, “2017 Assistive Technology AssessmentPackage,”thatisavailableforfreeatitswebsite
• Several PDF downloads are available, including “Assistive Technology Decision Making Guide,” “AssistiveTechnologyTrialUseSummary,”and“ClassroomObservationGuide.”
Youmayalsowanttocheckoutanewbookbyafriendandcolleagueofmine,ChristopherR.Bugaj,titled The New Assistive Tech: Make Learning Awesome for All! (https://wwwisteorg/resources/product? id=4111&name=The+New+Assistive+Tech) It’s a great resource to help public school educators select, purchase,andusetechnologytohelpallstudents,especiallythosewithspecialneeds.
USEOFSWITCHSOFTWARE
Someindividualswithsignificantmotorimpairmentsneedtoobtainaccesstocomputersormobiledevices with the use of switches and scanning They may be unable to use their hands to touch a screen or use a mouse or trackball. If a person is able to reliably move one part of the body, he or she can use technologies thatofferspecialaccessmethods Foot,shoulder,orheadmovement,andeveneyegaze,canbeusedtoaccess technology There are many types of access solutions available with a wide range of price points and features Fortunately, switch access is now included in the accessibility features of many of the mobile devices we use. The Apple iOS operating system was the first to include Switch Control for iOS 7 in 2013 Android devices running Lollipop in 2014 began to offer switch access The sophistication of the accessibility features continues to improve. Matching the right access technology to the abilities of the individual is incredibly important,andprofessionalhelpshouldbeused
Options exist for those who use a single switch to operate computer software and mobile device apps A single switch can be used to simulate mouse function or touch for a touchscreen. People can also use multiple switches, giving access to more controls Switch-friendly software programs offer special on-screen layouts withseveralchoices Usersthenusetheswitchtoselectdesiredchoicesasahighlightedboxmovesoveritems on the screen one after the other, until the student presses the switch to make a selection. This process is referredtoasswitchscanning
The process of scanning involves many skills, such as controlling the switch, paying attention to the pictures or sounds on the screen, and watching what happens after the selection is made. Mounting of the switch,bodypositioning,andswitchselectionandsetupallhavetobeconsidered Whenanindividualisonly
able to access software via a single switch, software and app selection is more limited Many of the products describedinthisguideareaccessibleforpeoplewhoneedtouseaswitch
Most new mobile devices offer switch access as an accessibility feature. If it is difficult to determine whether switch accessibility is available on your device, go to the settings menu and explore the accessibility features Yourdevicemaybeabletobeusedasasingleswitchormayconnectwithexternalswitches Youcan access videos on this topic by searching for information on accessibility features and switch access on your deviceonYouTubeoryourfavoritesearchengine.
More detailed guidance on the use of technology and potential software and apps that may help users who needtouseswitchescanbefoundatthefollowingwebsites:
•Google(Chrome,Android):https://www.google.com/accessibility
•Apple(Mac,iOS):https://supportapplecom/accessibility
•Microsoft:https://www.microsoft.com/en-us/accessibility/default.aspx
•AbleNet:https://www.ablenetinc.com/technology/switches
•JudyLynnSoftware:http://wwwjudylynncom
•HelpKidzLearn:http://www.helpkidzlearn.com
•ShinyLearning:http://www.shinylearning.co.uk
•Glenda’sAssistiveTechnology:http://atclassroomblogspotcom
▶ Glenda Hampton Anderson wrote a helpful post highlighting online and iOS activities to use with switchaccessathttp://atclassroom.blogspot.com/2009/04/switch-use.html.
WHICHTYPEOFDEVICESHOULDYOUUSE?
It is important to understand the advantages and disadvantages of desktop computers, laptops, tablets, and other devices when choosing a device already available or investing in a new device. Here are a few considerations:
•Sizeandweight: Having a large screen can be helpful, but larger screens often equate to heavier devices Willyourstudentbecarryingthisdevicefromclasstoclass?Someofthesmallermobiledevicesaremore portable but may be more difficult to use for typing and viewing documents or may have different operatingsystems
•Onlineaccess: If you are considering the purchase of a Google Chromebook, a very affordable computer that many schools use, make sure that your student has reliable Internet and does not require additional softwarethatcan’tbeprovidedbyGoogleappsandextensions
•Techsupport: If you are purchasing a new device for your student, discuss with the school which devices are currently supported in the student’s environment during the day. Some schools that are able to support Google, Apple, and Microsoft devices encourage students to bring their own devices Others havechosentoteachusingaparticularplatform.
•Price:AndroidtabletsandChromebookcomputersaretypicallytheleastexpensiveoptions,buttheymay not offer features that your student needs If price is not a factor, iPads and MacBook laptops are often preferable;theyincludeappsandfeaturesnotavailableonotherdevicesthatarehelpfulforstudentswith complex communication needs as well as literacy and learning differences. You will notice that the apps includedinthisbookaremorelikelytobecompatiblewithiOSdevicesthanAndroid Thatbeingsaid,if
the other students in the classroom or others who will be supporting the individual prefer Android devicesorChromebooks,anon-Appledevicemaybeperfectlysuitable Itismostimportanttofigureout whichfeaturesarethebestmatchtothestudent’sneeds.
• Supportnetwork: It can be helpful to consult with computer-savvy friends, colleagues, or other parents, as well as your student’s technology staff at school, when determining which type of technology to purchase.Someschoolshave“goneGoogle,”whileothersareApple-orMicrosoft-basedschools.
• Reviews: Computer magazine reviews, such as those in PC Magazine (http://www.pcmag.com) and Consumer Reports (http://wwwconsumerreportsorg), are often insightful for reviewing mainstream technologies.
OPERATINGSYSTEMSANDDEVICES
An operating system is the software on a device that manages the programs and determines what the user can do It is very important to know what assistive technology you will want to use when deciding which device to purchase in order to make sure that they are compatible. Once you have identified the operating system of your device, I highly recommend that you become familiar with the settings as well as the accessibilityfeatures
Theoperatingsystemsondevicescontinuetobeupdated.Sometimestheupdatesoffermajorchanges,and other times updates are barely perceptible It’s important to install the updates in order to minimize potential harmfromvirusesandhackers,butitcanalsobedifficultfordeveloperstokeepupwiththechangesthatmay affect how their products perform. I generally wait at least a few months prior to installing major updates to makesurethatIhavetimetobackupimportantdataandprovidedeveloperstimetoupdatetheirappsincase theupdatecausesproblems Inmostcases,appsandsoftwarewillcontinuetoworkjustfinewithupdatesand even improve with new functionality. From time to time, the upgraded operating system will render an app obsolete.Thefollowinglistofoperatingsystemsandresourcesincludeshelpfullinkstoaccessibilityfeatures.
•GCFLearnFreeorg(https://wwwgcflearnfreeorg/topics)offersavarietyofhelpfulvideotutorialsforthe variousoperatingsystems.
•MicrosoftWindows(https://www.microsoft.com/en-us/Accessibility/windows) includes video demos for userswhohavevisual,hearing,physical,andcognitivechallenges
• Chrome OS (https://support.google.com/chromebook/answer/177893?hl=en) is the operating system that Chromebooks use, designed to be primarily used when connected online. Chrome OS uses the Chrome web browser as the primary interface and does not rely exclusively on touchscreen access
Accessibility features include many items that macOS and Windows also include, such as text to speech, displayoptions(highcontrastandscreenmagnifier),keyboardfeatures(StickyKeys,wordprediction,and anon-screenkeyboard),andmouseandtouchpadtools(tapdraggingandalargecursor)
• macOS (https://support.apple.com/guide/mac-help/use-accessibility-features-mh35884/mac) offers accessibility features to help individuals who have vision, literacy, hearing, and mobility limitations. This istheoperatingsystemusedonApple’sMacfamilyofcomputers
•iOSdevices(https://developerapplecom/accessibility/ios) offer many choices for individuals with special needs. The iPad is my tablet of choice and offers a wide selection of accessibility features that will be discussedthroughoutthisbook
• Android (https://www.android.com/versions/oreo-8-0) includes an extensive set of accessibility features, such as TalkBack, Switch Access, Select to Speak, Color Lens, and customizable and high-contrast keyboards. Please keep in mind that different Android devices may include different features. Android is Google’stabletoperatingsystembecauseitisbasedonthetablet’sandphone’stouchscreenuserinterface.
SELECTIONDEVICES
Wheneverpossible,Iprefertousemainstreamproductsforbothfinancialandsocialreasonswhenhelping others.Moststudentsrejectusingitemsthatwillattractattentionandmakethemfeeldifferentfromothersin their classes However, there are a variety of peripheral devices that can be used to help people who have difficulty accessing devices If you are in the market for devices created for special populations, consider visitinghttps://turningpointtechnology.com.
MICE
When using a computer, the standard mouse may be fine for most people with good hand control However, many people with disabilities have impaired fine motor movements and find it difficult to see the movement of the cursor on the computer screen Some people are unable to use their dominant hand due to weakness, paralysis, or coordination deficits The use of the mouse may be confusing for people with significant cognitive deficits, who may do better with a touchscreen. Most operating systems enable users to customizetheuseofamouseandcursorsize
TRACKBALLS
Trackballs are often a good solution for individuals with coordination difficulties with their hands because the cursor can be controlled with a finger. The device stays in one place as the user moves the ball. The BIGtrack Trackball (available at https://wwwablenetinccom/bigtrack-trackball-switch-adapted) requires less finemotorcontrolthanastandardtrackballandisruggedlybuilt
TOUCHSCREENS
Touchscreens are a feature of many newer devices. They are activated by touching the screen with a fingertip or stylus This type of direct selection is often more effective and intuitive for younger children or individuals with significant cognitive deficits Touchscreens are used on most tablets and are increasingly found on laptops and computers. If a student has tremors or issues activating the touch feature of the screen, trytestingsomeoftheaccessibilitysettingsforthetouchscreen
SWITCHES
Technology is available to assist people with little or no use of their hands. People who have reliable movementofatleastonepartoftheirbodycancontrolthecursoronthescreen Reliablemouthmovementor eye gaze can control a computer Special switches make use of at least one area over which the individual has voluntary control, such as the head, knee, or mouth. To make selections, people use switches activated by movement
KEYBOARDS
Keyguards and keyboard overlays are helpful accessories when needed They can decrease the number of
unwanted keystrokes due to someone with poor manual coordination hitting more than one key at a time, keep the mechanics of a keyboard safe from the effects of spills and drooling, and help those who struggle to identifythekeys.Formoreinformation,visithttp://www.keyguardat.com
Expanded keyboards that have larger keys spaced farther apart can replace standard keyboards for people with limited fine motor control Mini-keyboards provide access for those who have fine motor control but lack the range of motion to use a standard keyboard. There are also keyboard trays with adjustable arms that canbepurchasedforindividualizedpositioningoftheuser.
Most operating systems include special features that can help with keyboard use To access those features, studytheaccessibilityoptionsofyouroperatingsystem.Thekeyboardsofmanynewdevicesincludeanimage of a microphone. When the microphone is selected, the user can speak aloud and the device will generate the correspondingtext
SPEECHINPUT/DICTATION
Speech input provides another option for people with disabilities who have difficulty typing. This feature may be referred to as speech recognition or speech to text (STT) Through speech-recognition technology, the user controls the computer or enters text by speaking into a microphone This is one feature that has greatlyimprovedoverthepastfewyears.
Manymobiledevicesarenowabletoautomaticallytranslatespokenspeechintowrittentext,andmanyare even able to translate the words into other languages Many professionals and families believe that speech to text is the ideal solution for students with written expression deficits. In the past, using speech-to-text softwarewasamuchmoredifficultprocessbecausesoftwareneededtobetrainedtorecognizespecificvoices This may still be the case if an individual’s speech is difficult to understand In order to effectively use speech to text, users need to speak clearly in an organized way so that the resulting text is transcribed properly. The transcribedtextisn’talwaysaccurate,andcorrectionsmayneedtobemade Usingspeechtocreatetextcanbe verydifficultforpeoplewhohavecommunicationandcognitivedeficits ThereareseveraloptionsthatImost oftenuseforspeechtotext:
•themicrophonegenerallyfoundonanymobiledevice’skeyboard;
•voicetypinginthetoolbarofGoogleDocs(https://wwwdocsgooglecom);
•theaccessibilityfeatureofspeechtotextincludedonMacandWindowscomputers;and
•WordQ+SpeakQV4EnglishonaPC,whentheabovesolutionsdon’tworkduetoimprecisearticulation (http://buyusagoqsoftwarecom/WordQ-SpeakQ-version-4-p/wqsq4-en-01htm)
HEADSETSANDMICROPHONES
Much of the software described in this guide is for recording and listening to speech. Mobile devices now usebuilt-inmicrophonesandspeakersthatarefarsuperiortocomputersusedinthepast Ifthetechnologyis going to be used in a quiet environment and the use of sound won’t disturb others, then additional purchases may not be needed. If you are working with these assistive tools where there are distractions and others need quiet, it is often a worthwhile investment to purchase a good set of headphones with a built-in microphone andexternalnoisereductionfeaturesforusewithvoicerecording.
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8. A bisexual free form gives origin to a bisexual parasitic form living in an animal: example, Leptodera appendiculata in Snails.
9. The eggs develop in the earth, and give rise to embryos which are transferred whilst still in the egg-cell to the body of an animal. The embryos hatch out and form bisexual parasites: examples, Oxyuris, Trichocephalus.
10. The larvae live in insects, the sexual worms in water or in the earth: example, Mermis.
11. The larva lives encapsuled and is passively transferred to a second animal: examples, Ollulanus, from Mouse to Cat; Cucullanus elegans, from Cyclops to Perch; Spiroptera obtusa, from Meal-worm to Mouse.
12. The sexual form lives for a short time in the intestine of a Vertebrate, and produces larvae which bore through the intestinal wall and become encapsuled in the tissues: example, Trichina spiralis.
13. The sexual animal lives in the trachea of birds; the ova containing embryos are coughed up and are taken into other birds with food. They quit the egg-shell and wander into the air-sacs, and finally into the trachea: example, Syngamus.
14. There are two larval forms; the first lives in water, the second in the lungs of Amphibia, whence they wander into the intestine and become sexually mature: example, Nematoxys longicauda in Triton alpestris Parasitism.
1. Effect of Parasitism on the Parasite.—The usual effect of parasitism on the parasitic organism is that the various organs necessary for a free life tend to degenerate, whilst there is a multiplication and development of organs of adhesion, by means of which the parasite maintains its hold on its host. There is further an immense increase in the powers of reproduction, which may take the form of an increase in the number of fertilised eggs produced, or the parasite may at some time of its life reproduce asexually, by budding, or fission, or parthenogetically.
Of the various classes of animals which are more or less parasitic, the Nematodes show less difference between the free-living and parasitic members of the group than obtains in any other class. With few exceptions, such as Sphaerularia, Allantonema, and one or two others, the parasitic forms have undergone but little degeneration. It is true that they have no eyes such as the free forms often possess, but in other respects, such as in the nervous, muscular, and digestive systems, they do not show any marked retrogression; further, the mouth-armature is developed in many free forms, and is not confined to the parasites.
The group has developed no methods of asexual reproduction by budding or fission, such as are found in Platyhelminthes; and the cases of an alternation of generations in which a sexual form alternates with a parthenogenetic form, are rare, e.g. Rhabdonema nigrovenosum; and it seems possible that even when parthenogenesis has been described, further observation may show that the parthenogenetic stage is really a protandrous hermaphrodite, in which case the alternation of generations in Nematodes, i.e. the hermaphrodite alternating with the dioecious form, is a case of heterogamy or the alternation of two sexual generations.
On the other hand, parasitic Nematodes produce enormous numbers of eggs. Van Beneden states that 60,000,000 have been computed in a single Nematode, and this multiplication of ova is absolutely
necessary, for the chance of the embryo reaching the right host, in which alone it can develop, is always a small one.
It is a common thing to find that parasites are either hermaphrodite or that the male is degenerate, as is the case with many of the parasitic Crustacea, but with one or two exceptions the Nematoda are bisexual, and although, as a rule, the males are smaller than the females, they show no other trace of degeneracy
In spite of the fact that the class as a whole shows but few special modifications consequent on a parasitic mode of life, it is clear that the Nematoda are peculiarly adapted for such a mode of life. Their elongated thread-like bodies afford little resistance to the passage of the food, which, as it passes through the intestine of the host, might tend to carry the parasites out of the body. At the same time their shape enables them to pierce and wriggle through the various tissues without making any very serious lesions such as might prove fatal to their host. Their extraordinary power of resisting desiccation both in the egg and in the adult state vastly increases their chances of ultimately hitting on the right host. They are capable of living in a state of suspended animation for months, and even years when dried (vide p. 136), and of resuming their activity on being moistened.
The great faculty this group shows for living parasitically is evinced by the extraordinary variety of life-history presented by the different species. There is scarcely a stage which may not be parasitic; the eggs, the larvae, the adults are all in some cases free, in others parasitic, and in many cases first the one and then the other.
2. Occurrence and Effect of the Parasite on the Host.—Von Linstow states that the only law that can be derived inductively from the study of the life-history of Nematodes is that those that live in animals never pass through all their stages of development in the same organ; consequently, in considering the distribution of the parasites within the body of their host we have a double habitat to
consider Many forms, such as Trichina spiralis, wander from the intestine to the muscles; others, such as Filaria medinensis, from the alimentary canal to the lymphatics or blood vessels or subcutaneous tissues. Others pass from the body-cavity to the intestine, as the Mermithidae, which infest Insects, or from the stem and leaves of a plant to its flower, as in the case of Tylenchus tritici.
With regard to their occurrence in the different classes of the animal kingdom, they have been most frequently observed in Vertebrates and in Insects. They are comparatively rare in the other large divisions. Many genera are confined to certain hosts: thus Ascaris, Filaria, Trichosoma occur only in Vertebrates; Spiroptera (with one exception) in Mammals and Birds; Cucullanus in Fishes and Amphibia; Strongylus and Physaloptera in Mammals, Birds, and Reptiles; Dochmius, Pseudalius, Trichocephalus in Mammals; Dispharagus, Hystrichis, Syngamus in Birds; Nematoxys, Hedruris in Amphibia and Reptiles; Ichthyonema in Fishes; and Isacis and Mermis in Insects.
Twenty-two species have been described as parasitic in man, of which perhaps the most dangerous are Filaria medinensis, the three varieties of F. sanguinis hominis; Dochmius (Ancylostomum) duodenalis, and Trichina spiralis. The Ascaridae, as Ascaris lumbricoides and Oxyuris vermicularis, though painful, seldom cause death.
The enormous number of parasites harboured by one host is shown by the fact mentioned in Leuckart's Parasites of Man, that Nathusius[203] took from a single black stork 24 specimens of Filaria labiata from the lungs, 16 Syngamus trachealis from the trachea, more than 100 Spiroptera alata from the coats of the stomach, besides several hundred Trematodes belonging to several different species (see p. 63). Even this has been surpassed in the case of a young horse, in whose body Krause found 500 Ascaris megalocephala, 190 Oxyuris curvula, several millions of Strongylus
tetracanthus, 214 Sclerostomum armatum, 287 Filaria papillosa, 69 Taenia perfoliata, and 6 Cysticercus forms.
It is impossible here to enter into a full description of the destruction caused to domesticated animals and crops by the presence of these parasites; full details will be found in books dealing especially with this question, such as Neumann's Parasites and Parasitic Diseases of Domesticated Animals A couple of cases will show how important this matter is to the farmer. Crisp estimates that Syngamus trachealis causes the death of half a million pullets in England every year, and Mégnin states that in a single pheasantry 1200 victims died daily; again, the loss of one-third the crop of beetroot is by no means uncommon when it is infested with Heterodera schachtii. These show the practical importance of what at first sight seem quite insignificant animals, and the necessity for the minutest observation, for only when we are fully acquainted with all the details of the lifehistory of a parasite are we in a position to successfully combat it.
Sub-Order II. Nematomorpha.
Until the last few years it has been customary to regard the Gordiidae as a family of Nematodes. Although in external appearance and life-history they closely resemble the members of this group, yet recent research has shown so many important morphological differences between them and the Nematoda, that most zoologists are now agreed in placing them in a different subOrder, the Nematomorpha, a name first suggested by Vejdovsky.[204]
F 82 A water plant around which a female Gordius is twining and laying eggs a, a, Clump and string of eggs (From von Linstow
[205])
The Gordiidae comprise but two genera, Gordius and Nectonema. The latter has but one species, N. agile Verr., and is marine; the former, on the other hand, is exclusively fresh-water, and contains a very large number of species. Gordian worms are frequently to be found in ditches, ponds, or large puddles, moving with an undulating motion through the water, or twining and writhing round water-plants; they are scarcer in running water. In shape they are like a piece of thin whip-cord, slightly tapering at each end; the male, however, is easily distinguished from the female by its forked tail (Fig. 89). Not unfrequently a considerable number are found inextricably tangled together into a knot, and the name of the genus refers to this fact. Where numbers have suddenly appeared in water hitherto free from them, legends have sprung up which attribute their presence to a rain of worms; in reality they have come out of the bodies of Insects in which they are parasitic for the greater part of their life.
The genus Gordius passes through three distinct stages, of which the first two are larval and parasitic; the third is sexually mature and lives in water. The second larval stage closely resembles the adult, but the reproductive organs are not developed. The following account of the structure of this larval form and of the adult is in the main taken from von Linstow.[206]
The whole body is covered with a well-developed two-layered cuticle, which in the adult is marked out into areas, and bears numerous minute sensory bristles, which are especially developed in the neighbourhood of the cloaca of the male. Beneath this is a hypodermis which differs markedly from the sub-cuticle of Nematodes, inasmuch as it consists of a single layer of polygonal nucleated cells. Within this lies a single layer of longitudinal musclecells, which differ from the corresponding layer of Nematodes in having that part of their medulla which is not surrounded by the contractile portion directed outwards towards the hypodermis, and not inwards towards the body-cavity.
F . 83. Transverse section through a young male Gordius tolosanus
Duj. (From von Linstow.) Highly magnified. a, Cuticle; b, hypodermis; c, muscular layer; d, parenchyma; e, alimentary canal; f, nervous system; g, cells of the testis.
The body is in the younger stages practically solid, the interior being filled with clearly defined polygonal cells which are arranged in definite rows; in later life certain splits arise in this tissue which subserve various functions; between these splits strands of tissue are left which form mesenteries, and some of the cells remain lining the muscular layer (Fig. 86). These cells have been described by Vejdovsky as a definite somatic, peritoneal epithelium, but this was not found by von Linstow. Besides forming the mesenteries, and acting as packing between the various organs of the body, these cells also form the ova and the spermatozoa.
The splits which have appeared when the animal has reached the second larval stage, are two dorsal and a ventral; the latter contains the alimentary canal, and may be termed the body-cavity, the former will develop the generative organs. The mouth is occluded in the older larvae, and in the adults there is a distinct but solid oesophagus which passes into a tubular intestine. The intestine consists of a single layer of cells surrounding a lumen; it runs straight to the hinder end of the body, where it opens in both sexes with the ducts of the reproductive organs.
The nervous system consists of a well-defined circumoesophageal ring with two dorsal swellings, and, arising from this, a median ventral cord which runs the whole length of the body. The cord consists of three longitudinal strands with ganglionic cells below them; the latter, though they lie within the muscle layer, maintain a
connexion with the hypodermis. Behind, the nerve-cord splits in the male, one half passing into each caudal fork. In the adult a pair of black eyes can be detected on the head; the only other sense organs are the tactile bristles mentioned above. Excretory organs are unknown.
F . 84. Section through a young female Gordius tolosanus. (From von Linstow.) a, Cuticle; b, hypodermis; c, muscular layer; d, parenchyma; e, alimentary canal; f, nervous system; g, egg-sac; h, ovary
The generative organs only attain maturity in the adult, which is, in fact, exclusively devoted to reproduction. No trace of testes is found in the larva, though the two dorsal splits from the walls of which the spermatozoa will arise are present. They are lined by a definite epithelium (Fig. 83), and this serves at once to distinguish them from the body-cavity. Posteriorly the splits narrow and become the two vasa deferentia which open one on each side into the cloaca. The cells lining the lumen give rise to secondary cells, and these become spermatozoa, the process extending from behind forwards. The external organs—bursa, etc.—described by Vejdovsky were not found by von Linstow
F . 85. Section through a mature female Gordius tolosanus. (From von Linstow.) Lettering as in Fig. 84; g, egg-sac; h, ovary.
F . 86. Section through a female Gordius tolosanus when the deposition of ova is almost complete. a, b, c, d, e, and f, as in Fig. 84; g, egg-sac; h, ovary almost empty; i, dorsal canal containing eggs; j, receptaculum seminis
In the female larva two similar splits are present; these form the eggsacs. Posteriorly they end in two short oviducts which open into a uterus, in which fertilisation takes place, and in which the secretion arises which cements the eggs together. In the adult the ovaries and a receptaculum seminis are found, in addition to the organs present in the larva. The ovaries are formed from modifications of the packing tissue; they begin close behind the head, and soon attain such dimensions as to compress the egg-sacs and body-cavity to small slits. After a time the wall between the ovary and the egg-sacs becomes absorbed, and the eggs grow into the latter. In the old females, where the egg sacs are empty, there is a considerable space round the exhausted ovary, into which eggs continue to fall off; there is also a median dorsal canal which contains a few eggs. By this time the wall between the ovary and the egg-sac has again appeared.
One of the most interesting points about the female is that, according to Vejdovsky, the ovary is segmented, the cells which form the ova being heaped up in segmentally-arranged masses. This observation, if correct, is almost the only instance of segmentation recorded in the group Nemathelminthes.
F . 87. Nectonema agile Verrill. A, The adult. Magnified. (After Fewkes.) B, Longitudinal section through the head. × about 20.
(From Bürger.) a, Mouth; b, circumoesophageal commissure (dorsal); c, cell of salivary gland; d, septum cutting off head from rest of body; e, testis; f, ventral cord; g, oesophageal cells; h, lumen of oesophagus; i, cerebral ganglion (ventral).
The only other genus which is associated with Gordius in the group Nematomorpha is Nectonema, of which there is as yet but one species known, Nectonema agile Verr.[207] Our knowledge of the anatomy of this worm is due mainly to Bürger[208] and Ward.[209] Nectonema is a marine worm found swimming near the surface of the sea with rapid undulatory motion. The males are from 50 to 200 mm. long, the females from 30 to 60 mm. The body is faintly ringed, and bears two rows of fine bristles on each side. Owing to a curious torsion of the body through a right angle, the lateral bristles of the anterior third seem to be placed in the ventral and dorsal middle line. They are very easily broken off. The body is divided into a small anterior and a large posterior chamber by a transverse septum placed a little way behind the head. The anterior chamber contains the brain and is lined by a definite epithelium, the posterior is not. The layers of the skin correspond with those of Nematodes or of Gordius, but the hypodermal cells show no cell outlines; still they are not so modified as in the former group. The hypodermis is thickened in the median dorsal and ventral line, and the single nerve-cord lies in the latter.
The alimentary canal is degenerate, as in Gordius. A mouth exists, but it is minute, and opens into a very fine tube lined with chitin, which pierces through the substance of a single elongated cell. This
minute oesophagus, with its coextensive cell, reaches back to the transverse partition, but behind this a few other cells become associated with it, and ultimately the lumen of the alimentary canal is surrounded by four cells; but the number diminishes behind, and soon only two cells surround the tube at any one level, and the intestine dwindles away some little distance in front of the tail. There is no sign of an anus. A circumoesophageal nerve-ring exists, of which the ventral part is by far the larger (Fig. 87); it gives off a ventral nerve-cord, which swells posteriorly in the male into a large anal ganglion, far bigger than the brain, and larger in the male than in the female.
The testes consist of a dorsally placed sac, continuous behind with a vas deferens; this opens at the posterior end, which is pointed and slightly curved ventrally. The ovary is unknown; but females have been found with their body-cavity crammed with ova; these escape, like the spermatozoa, from a genital pore at the posterior end of the body.
Classification.—The separation of the Nematomorpha from the Nematoda depends mainly on the character of the nervous system, the absence of the lateral lines and of the dorsal line, the character of the contents of the body-cavity, and the character of the reproductive organs. In Gordiidae the latter are always placed dorsal to the intestine, and ovaries and testes open alike at the hinder end of the body. The importance of the differences in the organs just enumerated has been considered sufficient to justify the removal of the Gordiidae from the Nematoda, and the establishment of the special sub-Order Nematomorpha for their reception; and although Nectonema has a dorsal line, and is in some other respects intermediate between the two groups, there can be little doubt that it is more closely allied to Gordius than to any member of the Nematoda, and it must therefore be placed with it in the Nematomorpha.
On the other hand, it ought to be mentioned that Camerano[210] found that the chief details of the fertilisation and development of the egg in Gordius closely conform with what is known of the same processes in Nematodes, and he is of opinion that these resemblances are sufficiently important to justify the retention of the group among the Nematoda.
Life-History.—The life-history of Gordius comprises four stages— the early development of the egg, the first larval form, the second larval form, and the sexually mature form. Both larval forms are parasitic, and during their life they are actively engaged in feeding; the free form, on the other hand, takes in no nourishment, and is exclusively engaged in reproduction.
F . 88. Abdomen of Pterostichus niger with the terga removed to expose the Gordius larva within. Slightly magnified. (From von Linstow.)
Von Linstow[211] gives the following account of the life-history of G. tolosanus, a form which has been more fully worked out than any other. In the month of April numerous specimens of the beetle Pterostichus niger were found floating on the surface of the ditches and small ponds in the fields surrounding Göttingen. Some were found dead or dying; others appeared quite healthy, and these were swimming actively, endeavouring to reach land. Within the abdomen of these beetles, in about 20 per cent of those collected, the second larval form of the G. tolosanus was found. The longest larvae were 122 mm. in length, and very soft, partly snow-white and partly brown in colour; traces of the boring apparatus of the first larval form were still to be seen, but in other respects the larva only differed from the free form in the immaturity of its sexual organs. Besides the parasite
hardly anything was to be found in the abdomen of the beetle, the larva having eaten up all trace of the fat body and the generative organs of its host. The larvae bored their way out of the body of the beetle and became adult animals.
It is rather difficult to say what brings these essentially terrestrial beetles to the water, but von Linstow suggests that, as they live partly on snails, and at this time of year there are not many landsnails about, they may be in search of water-snails such as Limnaea. They may also be sometimes blown into the water by wind storms, but, whatever the cause is, their presence in water is essential for the continuance of the life of their parasites.
Once free in the water the Gordius is soon sexually mature; the fertilisation takes place in April, and then the female may be seen twisting and writhing round the stems of water-plants and laying the long bead-like strands of eggs (Fig. 82). The first deposition observed by von Linstow took place on 14th April, the last on 2nd August, and the period of egg-laying for each female extended over four weeks. At first the eggs are snow-white, but within twenty-four hours they turn brown in colour.
The development of the first larva within the egg takes about a month. When it emerges from the egg-shell it is minute, .065 mm. long, ringed anteriorly, and provided with a protrusible and retractile boring apparatus consisting of three chitinous rods; round the base of this piercing proboscis is a double crown of papillae, each bearing a spine (Fig. 90).
F . 89. The tail ends of a female Gordius (a) and a male (b) in copula × 1 5 (From G Meissner [212])
This first larval form breaks through the egg-shell and sinks to the bottom of the water, where it moves about sluggishly and awaits the arrival of the right host in which to take up its abode. This host is the larva of the Alder-fly, Sialis lutaria Lin. (vide vol. v. p. 444), and into this it bores and comes to rest in the muscles or the fat body. It does not form distinct capsules. It remains in this larva during the following winter, and in the spring passes over into the imago Sialis. The complete insect frequents the small plants growing along the water's edge, and falls an easy prey to the predaceous beetle Pt. niger. The larva is eaten, and undergoing a change becomes the second larval form mentioned above. It remains in the body of the beetle during the second winter, and finally returns to the water as the adult some eighteen or twenty months after it has been hatched from the egg.
F 90 Embryo or first larval form of Gordius tolosanus taken from the egg Highly magnified a and b, The bristle-bearing papillae on the head; c, the boring apparatus (From von Linstow )
From the above account of the life-history of Gordius it will be seen that the chances of an egg reaching maturity are comparatively small, and to compensate for this a very large number of eggs are laid. In addition to the risk of the larvae not finding the right host at the right time, and of the first host not being eaten by the second, and the second not being drowned, there is the danger that the ditches and ponds in which the adults live may dry up, and, in fact, great numbers of worms perish by this taking place.
The sex of the adults may be told from their colour, the males being of a blackish brown, the females of a light clay brown; the former average 120 mm. in length, the latter 170 mm. The males are also more numerous, the proportion being seven to three. Camerano[213] has drawn attention to the fact that there is a certain polymorphism
in size, form, and colour which is especially common amongst the males; dwarf forms with mature reproductive organs exist, and he is of opinion that these differences depend both on the size of the second host and on the duration of the parasitic life.
In addition to the larva of Sialis lutaria, the first larval stage has also been found in the larva of Ephemera, Tanypus, Corethra, and Chironomus; the second in Carabus hortensis Fabr., Procerus (Carabus) coriaceus Linn., Calathus fuscipes Goeze, Molops elatus Fabr., several species of Pterostichus, and a number of other beetles. It is probable that its normal hosts are S. lutaria and Pt. niger, but it is clear that it often comes to rest in other insects. The view that the Gordiidae have no special hosts, but may either pass the whole of their life-history within one and the same animal, or, on the other hand, may inhabit animals belonging to very different groups, is held by Villot, who has paid great attention to the subject. He finds the first larval form encysted in the walls of the alimentary canal in fishes, such as Leuciscus phoxinus, the minnow, Cobitis barbatula, the loach, and Petromyzon planeri, the lamprey; in the larvae of Diptera, Ephemera, and beetles, in Planorbis (a water snail), in Enchytraeus (an Oligochaet); the second larval form in all kinds of insects, spiders, Crustacea, fish, frogs, birds (Otis), and in man, and these various habitats lead him to the conclusion that "Les Gordiens n'ont pas d'hôtes spéciaux." On the other hand, as von Linstow points out, it is contrary to our knowledge of parasites that a single species should develop equally well in the body of warm and cold-blooded Vertebrates and of Insects, and the explanation of the presence of the larvae in these various forms may either be that they belong to different species of Gordius or, more probably, that they are accidentally present, having passed into their hosts with drinking water
F . 91. Tarsal joint of an Ephemerid larva into which two Gordius larvae (a, a) have penetrated. Magnified. (From G. Meissner.)
The number of species of Gordius is large; over 100 are enumerated in the Compendium der Helminthologie, [214] the great majority of which inhabit insects.
The life-history of Nectonema is practically unknown; the adults have been found swimming near the surface of the sea at two places only: Newport, R.I., and Wood's Holl, Mass., on the south coast of New England. It has been fished close to the shore, from the end of June to the beginning of October, when the tide is going out at evening and there is no moon. This seems to indicate that it avoids the light. When first caught the worms move actively about, coiling themselves into figures of eight and then uncoiling; at the same time there is a rhythmical movement caused by waves of muscular contraction passing down each side of the body alternately; by this kind of motion they make rapid and definite progress through the water.
It seems probable that the adult Nectonema is preceded by one or more larval stages, and what appears to be a young form has been obtained from the thoracic cavity of a prawn, Palaemonetes, [215] which has thus some claim to be regarded as the host of this species, but nothing is known about its early life-history.
Sub-Order III. Acanthocephala.
The Acanthocephala, which form the third class of the Nemathelminthes, consists of but few genera; there are, however,
numerous species of very different size, varying from 10 to 65 cm. long in the female Gigantorhynchus (Echinorhynchus) gigas, to quite minute forms a few millimetres in length. The adult stage occurs in the alimentary canal of Vertebrates, as a rule in those which live in, or frequent water; the larvae are found in the bodies of certain Invertebrates, very frequently small Crustacea.
F . 92. Two specimens of Echinorhynchus proteus Westrumb., with their anterior ends embedded in the wall of the intestine of a Pike. Magnified with a lens. (From Hamann.)
Anatomy.—The body of the mature forms can usually be divided into three sections—the proboscis, the neck, and the trunk, but the middle region is not always discernible. The proboscis is armed with rings of hooks (Fig. 93) arranged in longitudinal rows; they are usually of two kinds, but in E. proteus of three. They have a certain specific value, but not much stress can be laid on the number of rings, e.g. in E. angustatus the number varies from eight to twentyfour The recurved hooks serve to fasten the parasite very firmly to the tissues of the host. The proboscis is hollow and retractile; it can be withdrawn into the body by means of muscles attached internally to its tip. It does not, however, pass straight into the body-cavity, but is retracted into a special cavity—the proboscis sheath—with a double muscular wall. The proboscis sheath may perhaps be looked upon as a septum, such as is found in some of the Nematomorpha, dividing the body-cavity into two parts. It is inserted into the bodywall at the junction of the neck and trunk or of the proboscis and trunk. In addition to the muscles which withdraw the proboscis into its sheath, there are two retractors running from the outside of the sheath to the body-wall; these serve to retract the whole sheath and its contents into the body-cavity of the trunk.
The structure of the skin is essentially like that of Nematodes, but the details are much more complicated. The whole body is covered by a thin cuticle secreted by the epidermis, which, as in the other groups, breaks down and forms a syncytium called the sub-cuticle. The minute fibrils which penetrate this layer are much more definitely arranged than in Nematodes; the largest of them run from without inwards, others run concentrically round the body. Large oval or spherical nuclei are scattered in the sub-cuticle, which is further honeycombed by a number of lacunae or spaces which are described below
F . 93. A, Five specimens of Echinorhynchus acus Rud. attached to a piece of intestinal wall, × 4; B, the proboscis of one still more highly magnified
Within the sub-cuticular layer is found a sheath of circularly-arranged muscle-fibres, and within this again a sheath of longitudinal muscles which do not extend into the proboscis; this inner layer lines the body-cavity, there being no epithelium within it. In their minute structure the muscle-cells resemble those of Nematodes.
The canals in the sub-cuticle form a very curious system of anastomosing spaces, in which a clear fluid containing fat globules circulates. The extent to which the system is developed varies in different species, but in all there is a pair of longitudinal canals which are situated laterally, and which give off the subsidiary channels in their course. The above description applies to the lacunar spaces in the skin of the trunk; those of the proboscis are quite distinct, and there is no communication between the two sets of spaces; in fact, the sub-cuticle in which the lacunae are formed is not continuous across the line of junction of the proboscis and the neck, or, when
the latter is absent, of the proboscis and the trunk, but it is interrupted by the ingrowth of a thin ring of cuticle which reaches down to the muscular layers (Fig. 94).
F . 94. A longitudinal section through the anterior end of Echinorhynchus haeruca Rud. (From Hamann.) a, The proboscis not fully expanded; b, proboscis-sheath; c, retractor muscles of the proboscis; d, cerebral ganglion; e, retinaculum enclosing a nerve; f, one of the retractors of the sheath; g, a lemniscus; h, one of the spaces in the sub-cuticular tissue; i, longitudinal muscular layer; j, circular muscular layer; k, line of division between the sub-cuticular tissue of the trunk and that of the proboscis with the lemnisci
All the spaces in the skin of the proboscis open ultimately into a circular canal situated round its base; on each side the canal opens into a sac-like structure which extends through the body-cavity towards the posterior end of the animal. These two lateral diverticula are termed the lemnisci. They have always attracted considerable attention from the workers at the group, and numerous functions have from time to time been attributed to them. They are more or less hollow, and their walls consist of sub-cuticular tissue surrounded with a scanty muscular coat; they contain the same fluid as the lacunae of the skin of the proboscis, with which they are placed in communication by means of the circular canal; and it seems most probable that, as Hamann[216] suggests, they act as reservoirs into which the lacunar fluid retires when the proboscis is retracted, and which, by means of the contractions of their muscular coat, force the
fluid into the lacunae when the proboscis is everted, and thus aid in its protrusion.
The parasitic habits of Echinorhynchus have had a deeper influence on the structure of the body than is the case with the Nematoda. All traces of an alimentary canal have disappeared, and the animals live entirely by the imbibition through the skin of the already elaborated fluids of their hosts. The power of absorbing fluids is shown by the fact that they swell up and become tense when placed in fresh water.
Until recently no definite excretory organs had been recognised, and the function of excreting the nitrogenous matter was by some assigned to the lemnisci. In 1893 Kaiser[217] described in G. gigas two organs which he called nephridia, placed dorsally to the ducts of the male and female reproductive organs. Each nephridium, which somewhat resembles a cauliflower, consists of a stalk or duct, opening at one end into the reproductive ducts, and at the other branching and breaking up into a number of secondary and tertiary twigs. The end of each twig is closed by a membrane pierced with a number of most minute pores, by means of which it communicates with the body-cavity; on the inner side the membrane bears a number of long cilia, which keep up an active flickering. The presence of these cilia is interesting, as elsewhere they are unknown throughout the Nemathelminthes.
F . 95. A, A longitudinal section through the terminal twigs of the nephridium of Gigantorhynchus gigas. (From J. E. Kaiser.) Highly magnified. a, Nucleus. B, A terminal twig more highly magnified; b, the porous membrane.
