Glossary

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Assistive Technology Lending Library(also: AT Lending Library, AT Library)

A service, often operated by state agencies or nonprofits, that allows individuals with disabilities to borrow assistive technology devices for trial periods before purchasing them or as a long-term resource. Lending libraries reduce the financial risk of trying new AT and help…

Assistive Technology Mainstreaming(also: Mainstreaming, AT Mainstreaming)

A design philosophy and practice where assistive technology features are integrated into mainstream consumer products rather than developed as separate, specialized devices. Examples include smartphones with built-in screen readers, tablets used for AAC, and headphones that also…

Assistive Technology for Cognition(also: ATC, Cognitive Assistive Technology, Cognitive Prosthetics)

Technology designed to support cognitive functions such as memory, attention, planning, and problem-solving for people with cognitive impairments. This includes reminder apps, task prompting systems, navigation aids, and other tools that compensate for difficulties in…

Assistive device customization(also: AT personalization, Custom assistive technology)

The process of tailoring assistive technology devices to match an individual's specific physical dimensions, functional abilities, preferences, and activity requirements. Traditional AT customization involves ordering from catalogs with limited options and long wait times, or…

Assistive technology(also: AT)

Any device, software, or equipment that helps people with disabilities perform tasks that would otherwise be difficult or impossible. In digital accessibility, this includes screen readers, screen magnifiers, switch devices, eye-tracking systems, voice recognition software, and…

Assistive use exception(also: Assistive use legal exception, Assistive purpose exception)

A proposed legal framework that would permit the use of always-on sensing technologies (such as wearable cameras or microphones) for assistive purposes in contexts where recording is otherwise prohibited, analogous to how service animals are allowed in no-pet spaces under the…

AssistiveTouch

An iOS accessibility feature that provides an on-screen menu of customizable touch-based shortcuts, allowing users to perform gestures and actions that might otherwise require physical buttons or complex multi-finger gestures. AssistiveTouch is particularly helpful for people…

Astigmatism

A common refractive error caused by an irregularly shaped cornea or lens, resulting in blurred or distorted vision at all distances. The cornea is shaped more like a rugby ball than a sphere, causing light to focus on multiple points rather than one. Astigmatism frequently…

Asymmetric Gameplay(also: Asymmetric Game Design, Asymmetric Multiplayer)

A game design approach where different players have different roles, abilities, information, or challenges within the same game. In the context of accessibility, asymmetric gameplay is a promising strategy for mixed-ability gaming because it allows each player's role and…

Asynchronous Communication(also: Async Communication)

Communication that does not occur in real time, allowing participants to send and receive messages at different times. In educational and workplace contexts, examples include email, discussion forums, recorded lectures, and messaging platforms. Asynchronous communication…

Asynchronous Control(also: Self-Paced Control, Asynchronous BCI)

A mode of interaction with a computer or assistive device where the user can issue commands at any time of their choosing, rather than being constrained to respond within system-defined time windows. In brain-computer interface research, asynchronous control is contrasted with…

Asynchronous Learning(also: Asynchronous Instruction)

A mode of education in which learners engage with instructional content on their own schedule rather than in real time with an instructor, typically via pre-recorded videos, written materials, or interactive modules. For accessibility, asynchronous learning removes some barriers…

At-Risk Populations(also: Vulnerable Populations)

Groups that are more likely to experience harm from digital attacks, surveillance, institutional discrimination, or other threats, and are disproportionately affected when such harms occur. Originally a security research term, it extends beyond traditionally recognized…

Ataxia(also: Cerebellar Ataxia)

A neurological condition characterized by impaired coordination and control of voluntary movements, typically caused by damage to the cerebellum or its connections. People with ataxia may experience unsteady gait, tremors, slurred speech, and difficulty with fine motor tasks…

Ataxia-Telangiectasia(also: A-T, Louis-Bar Syndrome)

A rare, inherited, progressive neurological disorder that typically appears in early childhood and causes increasing difficulties with movement, coordination, and immune function. Children with A-T usually begin walking at a typical age but experience progressive ataxia (loss of…

Athetoid(also: Athetosis, Athetoid Movement)

A type of involuntary movement characterised by slow, continuous, writhing motions, particularly affecting the hands, fingers, and face. Athetoid movements are commonly associated with athetoid cerebral palsy, a subtype of cerebral palsy that results from damage to the basal…

Athetoid Cerebral Palsy(also: dyskinetic cerebral palsy, athetosis)

A type of cerebral palsy characterized by involuntary, slow, writhing movements (athetosis) that affect the face, trunk, and limbs. It accounts for about 10-15% of cerebral palsy cases and results from damage to the basal ganglia. People with athetoid cerebral palsy often…

Athetoid Cerebral Palsy(also: Dyskinetic Cerebral Palsy, Athetosis)

A form of cerebral palsy characterized by involuntary, uncontrolled, slow writhing movements, particularly affecting the hands, feet, arms, and legs, and sometimes the muscles of the face and tongue. Athetoid cerebral palsy results from damage to the basal ganglia and is…

Athetosis(also: Athetoid movements)

A movement disorder characterized by slow, involuntary, writhing movements, particularly affecting the hands, feet, and face. Athetosis is one form of dyskinetic cerebral palsy and results from damage to the basal ganglia. People with athetosis often experience difficulty with…

Atomic Facts(also: Atomic Claims)

Self-contained units of information extracted from longer text, each representing a single verifiable claim or observation. In AI reliability research, decomposing model responses into atomic facts enables systematic comparison of what different models agree or disagree about.…

Attention(also: Attentional processing, Selective attention)

The cognitive process of selectively focusing on relevant stimuli while filtering out competing information. Cognitive neuroscience typically decomposes attention into three networks: alerting (maintaining readiness to respond), orienting (shifting focus across space or sensory…

Attention Capture Pattern(also: Attention Capture, Attention Grabbing Design)

A design element on a website intentionally crafted to draw users' attention toward content that serves the site's interests rather than the user's goals. Examples include bright promotional banners, flash sale notifications, pop-up offers, and visually prominent recommendation…

Attention Deficit(also: Attention Deficit Disorder, ADD, Attention Deficit Hyperactivity Disorder)

A cognitive condition characterised by difficulty sustaining focus, filtering distractions, and maintaining concentration on tasks. Attention deficits are common following traumatic brain injuries and are the defining feature of conditions such as ADD and ADHD. In accessibility,…

Attention Deficit Hyperactivity Disorder(also: ADHD)

A neurodevelopmental disorder characterized by persistent patterns of inattention, hyperactivity, and impulsivity that interfere with functioning and development. ADHD affects approximately 7.6% of children and 6.8% of adults worldwide and has three presentations: predominantly…

Attention Management(also: Attention Design)

Design strategies and techniques that help users direct, maintain, and recover attention while interacting with digital content. For users with ADHD, attention management in interface design includes minimizing distractions (reducing visual clutter, hiding non-essential…

Attention Mechanism(also: Attention)

A technique in neural networks that allows models to focus on relevant parts of the input when generating each part of the output, rather than relying solely on a fixed-length context vector. In sequence-to-sequence models, attention computes a weighted combination of all…

Attention Network Test(also: ANT, ANT-I, ANT-Child)

A computer-administered cognitive task developed by Fan, Posner, and colleagues that measures three functionally distinct attention networks — alerting (sustained readiness), orienting (shifting attentional focus in space), and executive control (resolving conflict between…

Attention Restoration(also: Attention Restoration Theory, ART)

A theoretical framework proposing that directed attention is a finite cognitive resource that becomes depleted through effortful focus and is restored through exposure to environments or activities that engage "soft fascination" — such as natural settings, visuals with fractal…

Attention Tunneling(also: Visual Tunneling, Attentional Tunneling, Cognitive Tunneling)

A phenomenon in which a user concentrates so narrowly on a primary information source - typically a visual overlay, head-up display, or instrument - that they fail to notice relevant events, objects, or hazards in their surrounding environment. In augmented and mixed reality,…

AuDHD(also: Autism and ADHD co-occurrence)

A term used by the neurodivergent community to describe the co-occurrence of autism spectrum disorder and attention deficit hyperactivity disorder in the same individual. Research suggests significant overlap between the two conditions, with estimates indicating that 50-70% of…

Audible Pedestrian Signal(also: APS, Accessible Pedestrian Signal)

A device attached to a pedestrian crossing traffic signal that conveys the WALK and DON'T WALK phases through non-visual cues — typically beeps, chirps, speech messages, or a vibrating tactile arrow indicating the direction of travel. APS support safe crossing for blind and…

Audience Modelling(also: Audience Modeling, User Modelling)

The practice of characterizing and formally describing distinct groups of users and their interaction characteristics to inform the design and evaluation of web interfaces. In accessibility, audience modelling involves identifying the specific abilities, disabilities, devices,…

Audification

A sonification technique that directly translates a data series into sound by mapping data values to audio waveform amplitudes, effectively "playing" the data as an audio signal. Unlike parameter mapping sonification, which maps data attributes to sound properties like pitch or…

Audio Augmented Reality(also: Audio AR, Augmented Audio Reality, Audio-Augmented Environment)

The overlay of digital sound — synthesised speech, music, earcons, or spatialised audio cues — onto a user's perception of their real or virtual environment. Audio augmented reality can be head-worn (via open-ear or bone-conducting headphones) or environmental (via fixed…

Audio Beacon(also: Auditory Beacon, Sound Beacon)

A spatial audio cue, typically a repeating tone or beep, attached to a specific location or object to help users with visual impairments navigate toward or identify points of interest in physical or virtual environments. Audio beacons vary in parameters such as pitch, timbre,…

Audio CAPTCHA(also: Audio HIP, Audio Human Interaction Proof)

An auditory alternative to visual CAPTCHAs, typically presenting distorted spoken letters, numbers, or words that users must transcribe. While intended as an accessible alternative for blind users, research shows audio CAPTCHAs have success rates of only 43-50% for screen reader…

Audio Cue(also: Auditory Cue, Sound Cue, Earcon)

A non-speech sound used to convey information in an interface. In accessible programming environments, audio cues represent code structures, syntax errors, or navigation landmarks—for example, a door-opening sound for an "if" statement or distinct tones for different indentation…

Audio Cues(also: Earcons, Auditory Icons, Sound Cues)

Non-speech sounds used in software interfaces to convey information, status changes, or events that would otherwise be communicated only visually. In accessible development environments, audio cues can indicate errors, warnings, code changes, and navigation events, providing…

Audio Customization(also: Audio Control, Sound Customization)

The ability for users to modify the audio characteristics of media content, including removing background sounds, enhancing speech clarity, adjusting volume levels for different audio channels, and controlling audio effects. Audio customization for accessibility goes beyond…

Audio Denoising(also: Noise Removal, Audio Noise Reduction)

The process of removing unwanted background sounds, noise, or audio artifacts from an audio signal while preserving the primary content (typically speech). In video accessibility for ADHD, audio denoising removes background music, sound effects, environmental sounds, and other…

Audio Describer(also: Describer, AD Writer)

A professional who writes and sometimes narrates audio descriptions for film, television, live performance, museums, and digital media. Audio describers craft concise verbal narration that conveys essential visual information (actions, settings, facial expressions, on-screen…

Audio Description(also: AD, Descriptive Audio, Audio Narration)

A narration track that describes visual elements of media, exhibitions, performances, or environments for people who are blind or have low vision. In museums, audio descriptions provide verbal accounts of exhibits, artworks, and spatial layouts. While valuable, research shows…

Audio Description(also: AD, Descriptive Video, Video Description)

A narration track added to video content that describes important visual information for people who are blind or have low vision. Audio descriptions are inserted during natural pauses in dialogue and other audio, conveying key visual elements such as actions, scene changes,…

Audio Description Authoring(also: AD Authoring, AD Creation, Description Writing)

The process of writing and producing audio descriptions for video content, live performances, or other visual media. AD authoring involves watching content, identifying key visual elements, writing concise and objective descriptions, timing them to fit within available gaps, and…

Audio Description Customization(also: Personalized Audio Description, Adaptive AD)

The ability for users to adjust the content and presentation of audio descriptions for video media based on their individual preferences. Customization dimensions may include detail level, emphasis on specific visual elements (such as facial expressions, scene settings, or…

Audio Description Script(also: AD Script, Video Description Script, Described Video Script)

An audio description script is the written text that forms the basis of an audio description track for video content. The script contains narration that describes visual elements — including actions, scene changes, character appearances, on-screen text, and other visual…

Audio Desktop(also: Auditory Desktop, Non-Visual Desktop)

An audio desktop is a logical workspace that provides the functionality of a graphical electronic desktop entirely through auditory interaction, including speech output, auditory icons, and audio-formatted content. Unlike screen readers that describe a visual desktop, a true…

Audio Ducking(also: Volume Ducking, Sidechain Compression)

An audio production technique that automatically reduces the volume of one audio track (such as background music or sound effects) when another track (such as narration or dialogue) is playing, ensuring speech remains intelligible. In accessible media production, audio ducking…

Audio Effect Placement(also: AE Placement, Sound Effect Timing)

The strategic timing of sound effects relative to narration or audio description in accessible media. Three primary placement strategies have been studied: pre-placement (sound effects before narration, which aids comprehension by providing advance context), overlapping…

Audio Emphasis Level(also: AEL)

A sonification technique that represents the degree of visual emphasis applied to text (such as larger font size, bold styling, or color changes) using distinct audio cues layered onto speech output. For example, strongly emphasized text might be accompanied by a bell ringing…