1B. Disability Types and 1C. Adaptive Strategies
Disability Categories
Source: Anki Deck
For types of disability, I've developed a mnemonic that goes with the song 'Head, Shoulders, Knees and Toes.' It goes, "Psychological, Compound, Mobility, Seizure, Mobility, Seizure, Mobility, Seizure. Cognitive, Compound, Mobility, Seizure; Visual, Auditory, Speech, Deaf-Blind." I do the actions as I say this.
Side Note: People in my region sing "Head and Shoulders" to the tune of "London Bridge." In my opinion, this is the only way it should be done.
Visual Disabilities
Source: Anki Deck
Blindness can refer to: partial blindness, low vision (can perceive light and dark and general shapes of large objects).
Colour-blindness especially applies to colours that are of equal luminosity.
Low-vision is a spectrum that is typically defined functionally.
Visual disabilities comprise of the three above.
Source: Deque Prep Course
Vision: Blindness
Deque goes a head and names some specific causes of Blindness including diabetes, macular degeneration, glaucoma, accidents/injuries, strokes, and retinitis pigmentosa. They also describe the legal definition of blindness in the US which has to deal with
visual acuity of 20/200 with corrective lenses or who has a field of vision (what can be seen in front of the person) that is 20 degrees in the eye that has the best vision
Fascinating, so there's actually two kinds of blindness here. One of which has a tiny field of vision (kind of like that guy, Paul, on TikTok that keeps on getting pranked by his husband) and the complete loss of visual acuity kind (kinda like Christine Ha from Masterchef).
Deque then talks about the Challenges and Solutions that Blind people encounter across a range of domains.
In the ICT domain
- Lack of textual alternatives are the challenge. Just.. provide them!
- Tools that are not keyboard-accessible are the challenge. Just... make them keyboard accessible!
- They can't see the digital interface (not just computers; think ATMs, kiosks, printers, copiers, GPS). The solution here is to use screen-readers (though I've never seen a screen-reader being used on an airport kiosk before. I'm flying soon, so I will take a peak!)
- The screen readers can't provide access if the content/interface wasn't designed to work with them. So make your coded interfaces and content compatible!
In the Built Environment/Architecture domain
- Blind people can't see while walking. These solutions can help Blind people navigate their surroundings without sight: canes, service animals, GPS with an audio interface, remote human navigators, raised tiles to indicate environmental elements, get rid of low-hanging things, clear pathways.
- Blind people can't signs of text within the built enviornment. These solutions can them orient regardless: Map applications, Braille labels that are placed in intuitive places (only helps people who know Braille, which is a minority), tactile models of buildings and floorplans, tools that provide descriptions (either through AI or human-aided things like Be My Eyes).
Consumer & Industrial Products
- Flat interfaces on devices like microwaves, ovens, are not accessible. Ideally, used interfaces with tactile controls like knobs and buttons. Audio interfaces, or remote control through a mobile device can be secondary solutions.
- Blind people can't read the text on consumer packaging. Embossed braile and braille stickers can help. I imagine tools that provide descriptions also help.
- Blind people can't read money to determine its value. In canada or other places that have accessible cash, this isn't really a problem. Non cash systems are another solution, as are applications on mobile devices that can photograph cash, and return the value of that cash.
- Blind lieople can't read printed materials. Digital formats are great. Optical character recognition can convert scanned images into readable text.
Vision: Low Vision
Some conditions are named here as well including cataracts, disabetic retinopathy, glaucoma, hemianopia, macular degeneration, and retinal detachment. It actually specifics names how these conditions manifest.
Some low vision types include
- Cataracts, where dark grey blind spots cloud the vision
- Diabetic retinopathy, where floating dark spots appear (kinda looks like seeing dark shadows caused by clouds when you're flying)
- Glaucoma results in a kind of tunnel vision.
- Hemianopia slices whole sides of your vision off.
- Macular degeneration have loss of vision at the center of the eye, but retains peripheral vision.
- Retinal detachment can have flashes of light, dark debris floating, and dark shadows obfuscating significant parts of vision.
Domain: General
- Small text can be hard to read. For printed text, alternative large print versions can help, as can alternative digital versions. For digital text, screen magnifiers, styling utilities, even screen readers can help.
- Low contast text can be hard to read. Solve this by choosing colour palettes with high contrast! People with low vision can also use software options to enhance to contrast of digital text.
Domain: ICT
- No options to set up custom color combinations can pose a barrier, so always allow the user to choose (don't override their stylesheets)
- Ensure content can be resized! It can be a barrier if you disallow this, or don't design with proper reflow in mind.
Colour Blindness
Forms of colour blindness include:
- Red-green color blindness (Deuteranopia and Protanopia are common conditions)
- Blue-yellow color blindness (Tritanopia)
- Total insensitivity/grayscale (Achromatopsia)
Barriers in the ICT Domain include
- When the option to enable custom color combinations is not available, so enable it!
General Barriers include
- Cases when certain color combinations can be difficult to distinguish, so don't design materials that require this distinction to be meaningful!
Auditory Disabilities
Source: Anki Deck
Auditory disabilities are caused by genetics, prematurity, infections, ear trauma, exposure to loud noises, aging: auditory processing disorder, deafness, HOH.
Deafness: 'total or near-total loss of hearing.' Some sign, some do not.
HOH: 6.1% of population/466 million people, mild to severe hearing loss. Adequate assistance may be provided by AT.
Central APD: 5% of global population, confused with other disorders, no hearing loss exists but difficulty understanding speech. Source of sound, distinguishing words, learning instruments, paying attention, learning new languages, responding in a timely way.
Source: Deque Prep Course
Auditory
'Auditory' as in referring to Deafness, HOH and central Auditory Processing Disorder.
Barriers in the ICT domain
- Audio content cannot be heard. Lots of solutions here and they will depend on whether the content is live or pre-recorded, as well as the preferences of the Deaf person, and what kind of medium it is. Options here include syncrhonized captions, sign language interpretation, signed interpretation, CART/STTR.
Speech and Language Disabilities
Source: Anki Deck
There are eight types: stuttering, cluttering, apraxia, dysarthia, speech sound disorders, articulation, aphasia, and muteness (no speech). Our mnemonic will be 'Amass A CDs': aphasia, muteness, articulation, speech-sound, cluttering, apraxia, dysarthia, stuttering. Picture someone collecting a bunch of CDs only from artists whose names start with the letter A.
Articulation can be broken into three categories: speech sound, phonological process, and motor speech disorders. Characterized by adding/leaving off sounds, distorting or swapping sounds.
Aphasia can affect comprehension of speech and reading/writing ability in addition to just produced speech. It results from brain injury (often a stroke), there are at least 2 million people in the US with it, and at least 250 thousand in Great Britain with it.
Muteness is either neurogenic (aphasia, apraxia, disarthia) or psychogenic. Psychogenic mutism has three types: selective elective, selective non-elective, and total. 0.47-0.76 of the population has selective mutism.
DeafBlindness
Source: Deque
General barriers include
- DeafBlind people being unable to communicate through sight or sound. Deque doesn't really have a great understanding of 'tactile sign language,' but to be fair, this is a very rapidly evolving space. Even users of the most traditional forms of tactile sign language do not restrict their signs and gestures to the hands. Tactile forms of communication are much more envolved and include things like the back, arms, chest, lap.
Barriers in the ICT Domain include
- Digital text cannot be seen or heard. But a screen reader can convert text and text alternatives to audio onto a refreshable Braille display, or printed via braille embosser.
- Visual and auditory feedback is not received, but haptic alerts can be received, so use that!
Source: Anki Deck
Deafblindness: Prescence of deafness and blindness, leaving touch as the primary communication medium. 0.2-2% of people are DeafBlind. My commentary: there are a lot of peope who identify as DeafBlind who don't meet these descriptions. Blindness and Deafness have spectrums from Blind to low vision, Deaf to HoH. DeafBlind people can sit anywhere along those two axioms, and with that definition, I assume the prevalence listed would be higher.
Mobility Disabilities
Source: Anki Deck
People with upper/lowe limb loss/disability, manual dexterity, difficulty cooordinating different organs of the body, and broken skeletal structure.
Four subareas are manual dexterity, ambulation, muscle fatigue and body size/shape.
Manual dexterity/fine motor control, requires coordination between the brain and muscles. Disability in this area can lead to handwriting issues and inability to dress independently. Can be hard to manipulate objects/use both hands at the same time. Children with ADHD have issues with this.
Ambulation is the ability toe walk with or without an assistive device. Ambulation disabilities can be disease based or injury based: think cerebral palsy and back injuries. 3.5% of adults in the US have ambulatory disabilities.
Muscle fatigue is associated with a bunch of causes and conditions and it's when basic tasks become very difficult. It can be in a specific part of the body and can present as soreness, twitching, trembling, cramping, and is associated with general weakness.
Body size or shape disabilities affect stature, proportions or shape. Dwarfism, acromegaly, rheumatoid arthritis are some examples. This is characterized by the prescence of other co-occuring conditions. My comment: not surprising that it falls into line in presenting 'obesity' itself as a disease. As scholars of fat studies note, this is an argument with no evidence, and the prevelance of it leads to lesser health outcomes for obese patients due to misdiagnosis and mistreatment in medical settings. So I'm not surprised to see this here, and I'm not happy about it.