Glossary

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Active Learning(also: AL)

A machine learning paradigm in which the algorithm iteratively selects the most informative unlabeled data points to query a human annotator for labels, enabling effective model training with minimal labeled data. Active learning uses sampling strategies such as uncertainty…

Active Listening(also: Attentive Listening)

A communication technique where the listener fully concentrates on, understands, and responds to a speaker, demonstrating engagement through verbal and non-verbal feedback. Active listening behaviors include maintaining eye contact, nodding, providing verbal acknowledgments,…

Active Noise Cancellation(also: ANC, Active Noise Control)

A technique that reduces unwanted ambient sound by using microphones to capture incoming noise and electronically generating an inverted (anti-phase) audio signal that destructively interferes with it, lowering the perceived noise reaching the listener's ear. ANC is the core…

Active Perception(also: Active Sensing, Sensorimotor Exploration)

A view of perception in which the perceiver is not a passive receiver of stimuli but an active agent who moves, orients, and manipulates the environment to gather the sensory information needed for a task. In accessibility and sensory substitution research, active perception is…

Active Support

A person-centred model of support that enables people with intellectual disabilities, including those with severe and profound disabilities, to participate meaningfully in everyday activities and relationships. Active support involves providing graded levels of assistance — from…

Activities of Daily Living(also: ADLs, Daily Living Activities, ADL)

Routine tasks that people perform every day for self-care and independent functioning, including reading, cooking, grooming, dressing, and managing household items. For people with low vision, performing ADLs can be significantly impacted by reduced visual acuity, contrast…

Activities of daily living(also: ADLs, Daily living activities)

The fundamental self-care tasks that a person performs routinely each day, including feeding, bathing, dressing, grooming, toileting, and mobility. Originally proposed by Sidney Katz in the 1950s, ADLs are used in healthcare and occupational therapy as a measure of functional…

Activity Monitoring(also: Activity Recognition, Activity Tracking)

The use of sensors, algorithms, and computational models to automatically detect and track a person's actions and behaviours within an environment. In assistive technology contexts, activity monitoring enables smart home systems and cognitive orthoses to understand what a person…

Activity Pacing(also: Pacing, Energy pacing)

Activity pacing is a self-management strategy used by people with chronic conditions such as Multiple Sclerosis, fibromyalgia, and chronic fatigue syndrome to manage limited energy and prevent symptom exacerbation. It involves planning and distributing physical and cognitive…

Activity Prompting(also: Skill Prompting)

A structured approach to encouraging skill development through customized, playful prompts that guide individuals through specific activities. In the context of disability and education, activity prompting involves designing short, engaging tasks tailored to a person's current…

Activity Theory

A conceptual framework originating in Soviet psychology (Vygotsky, Leont'ev) and widely applied in HCI, which analyses human action as goal-directed activity mediated by tools, rules, community, and division of labour. Activity Theory provides a structured lens for studying how…

Activity Tracker(also: Fitness Tracker, Step Counter, Fitness Band)

An activity tracker is a wearable device or smartphone application that monitors and records physical activity data such as steps taken, distance traveled, calories burned, heart rate, and sleep patterns. In accessibility contexts, activity trackers raise important design…

Activity schedule(also: Visual schedule, Picture schedule)

A visual support tool that breaks down tasks or routines into sequential steps represented by photographs, pictograms, or text, enabling individuals with autism spectrum disorder, intellectual disability, or cognitive impairments to independently follow procedures without…

Acts of Assistance

A framework for designing human-machine interactions in cognitive assistive systems, drawing on speech acts theory from linguistics. Each act of assistance is a structured communication from the system to the user, defined by its message type (such as recall, indicate, or…

Ad Blocker(also: Adblocker, Content Blocker)

A browser extension or built-in feature that prevents advertisements, trackers, and other unwanted content from loading on web pages, typically by matching requests against blocklists such as EasyList or EasyPrivacy. Ad blockers can substantially improve accessibility by…

Ad-Hoc Customization(also: On-the-Fly Customization, Real-Time Adjustment)

Making customization changes during content consumption rather than configuring all settings beforehand. For ADHD video viewers, ad-hoc customization was preferred by 75% of participants because it allows viewers to react to distractions as they encounter them while gaining…

Adaptable system

A system that can be configured using prior knowledge before use, as opposed to an adaptive system which changes dynamically during use. In accessibility, adaptable systems allow users or administrators to set preferences in advance — for example, selecting a high contrast…

Adapted Curriculum(also: Adapted Computer Curriculum, Modified Curriculum, Curriculum Adaptation)

An adapted curriculum is an educational programme that has been modified to accommodate the learning needs, styles, and abilities of students with disabilities while maintaining the core learning objectives of the standard curriculum. Adaptations may include one-on-one tutoring…

Adaptive Assistive Technology(also: AAT, Adaptive AT)

Assistive technology that monitors a user's current and past performance and automatically adjusts its functionality to match their changing needs. Unlike static assistive technologies with fixed settings, adaptive systems continuously observe user behavior — such as typing…

Adaptive Behavior(also: Adaptive Skills, Adaptive Functioning)

The collection of conceptual, social, and practical skills that people learn and perform in everyday life. Conceptual skills include language, literacy, and self-direction; social skills encompass interpersonal abilities and social responsibility; practical skills involve…

Adaptive Boosting(also: AdaBoost)

A machine learning ensemble method that combines multiple weak classifiers to create a strong classifier, with each successive classifier focusing on the examples that previous classifiers misclassified. In computer vision and accessibility applications, AdaBoost is widely used…

Adaptive Cursor(also: Adaptive Navigation Cursor)

A cursor or navigation pointer whose speed, sensitivity, or behavior dynamically adjusts based on context such as the amount of content, the current navigation granularity, or user preferences. In text editing for blind users, an adaptive cursor might move more slowly through…

Adaptive Disclosure(also: On-Demand Disclosure, Progressive Disclosure for Accessibility)

An interface design pattern in which supplementary accessibility content — summaries, keyphrase previews, navigation maps, alternative descriptions — is revealed only when the user requests it rather than shown alongside the primary content at all times. Adaptive disclosure…

Adaptive Environment(also: Adaptive System, Responsive Environment)

A physical or digital space that automatically adjusts its properties and behaviours in response to the people within it. Adaptive environments use sensors, machine learning, and actuators to modify lighting, sound, temperature, display content, or interaction modes based on…

Adaptive Gameplay(also: Adaptive Difficulty, Dynamic Difficulty Adjustment)

A game design approach in which the system automatically adjusts difficulty, pacing, or content based on the player's real-time performance and behaviour. In accessibility and therapeutic contexts, adaptive gameplay is used to create personalized experiences for users with…

Adaptive Hypermedia(also: AH, Adaptive Hypermedia Systems, AHS)

Interactive systems that build a model of each user's goals, knowledge, preferences, and context, then use this model to automatically adapt the content, presentation, and navigation of hypermedia documents. Unlike static web pages that present the same interface to all users,…

Adaptive Instrument(also: Adapted Musical Instrument, Accessible Musical Instrument)

A musical instrument that has been specifically designed or modified to be playable by people with disabilities. Adaptive instruments may use alternative input methods such as touch sensors, breath control, eye tracking, or simplified physical interfaces to enable music creation…

Adaptive Interface(also: Adaptive UI, Self-Adapting Interface)

A user interface that automatically adjusts its layout, content, or behavior based on user context, abilities, preferences, or device constraints without requiring explicit user configuration. Adaptive interfaces in accessibility research have included systems that modify visual…

Adaptive Interface(also: Adaptive User Interface, Self-Adapting Interface)

A user interface that automatically modifies its presentation, behaviour, or content based on detected user characteristics, capabilities, preferences, or environmental conditions. In accessibility, adaptive interfaces can respond to changes in a user's sensory, motor, or…

Adaptive Multi-Rate Codec(also: AMR, AMR Codec, AMR-NB)

A family of audio codecs used in mobile telephony to encode voice for transmission. AMR-NB (narrowband) operates at 300-3,400 Hz with bit rates from 4.75-12.2 kbps, while AMR-WB (wideband, also called HD Voice) extends to 50-7,000 Hz at 6.6-23.85 kbps. AMR-WB is adopted by 3GPP…

Adaptive Musical Instrument(also: Accessible Musical Instrument, Adapted Instrument)

A musical instrument that has been modified or purpose-built to enable people with disabilities to play music. Adaptive musical instruments may use alternative input methods such as head movement, breath control, eye tracking, or switch access to replace or supplement…

Adaptive Navigation(also: Adaptive Navigation Support)

A technique in which a system dynamically modifies the presentation of navigational elements (such as links, menus, or breadcrumbs) based on user characteristics, behaviour, or context. In accessibility applications, adaptive navigation can reorder, annotate, hide, or highlight…

Adaptive Optics(also: AO)

A technology that measures and corrects optical distortions in real time, originally developed for astronomical telescopes and now applied in ophthalmology and vision science. Adaptive optics systems use a wavefront sensor to detect aberrations and a deformable mirror or other…

Adaptive Rendering(also: Content Adaptation, Dynamic Rendering)

The process of automatically modifying how web content is presented based on a user's needs, preferences, or device capabilities. Adaptive rendering can involve transformations such as adjusting layout, reformatting text, replacing images with alternative representations,…

Adaptive Seating(also: Specialized Seating, Custom Seating)

Wheelchair seating systems and positioning devices customized to meet an individual's specific postural needs, providing support for the trunk, head, and limbs to enable optimal function and comfort. Adaptive seating is often essential for people with cerebral palsy or other…

Adaptive Sports(also: Para Sports, Disability Sports, Adapted Sports)

Sports that have been modified or specifically designed to enable participation by people with disabilities, including modifications to rules, equipment, or playing environments. Adaptive sports range from wheelchair versions of mainstream sports (basketball, rugby, tennis) to…

Adaptive Technology

Technology that has been modified or adapted from its original design to be accessible to people with disabilities, as distinct from assistive technology which is purpose-built for disability access. Examples include modified keyboards, adapted game controllers, or software with…

Adaptive Technology Resource Centre(also: ATRC, Inclusive Design Research Centre)

The Adaptive Technology Resource Centre (ATRC) was a research centre at the University of Toronto dedicated to developing inclusive information technology and promoting digital accessibility. Founded in the 1990s, the ATRC became one of the most influential accessibility…

Adaptive Typography(also: Context-Aware Typography, Dynamic Typography)

The practice of adjusting text presentation - font size, weight, line spacing, character spacing, contrast, and colour - automatically or semi-automatically in response to the user's current needs and context. Adaptive typography goes beyond static accessibility settings by…

Adaptive User Interface(also: Adaptive UI, Self-Adapting Interface, Intelligent User Interface)

A user interface that automatically modifies its behavior, presentation, or content based on observed user characteristics, interaction patterns, or context of use. In accessibility, adaptive interfaces can detect when a user is experiencing difficulty — through patterns like…

Adaptive User Interface(also: AUI, Adaptive Interface, Self-Adapting Interface)

A user interface that automatically detects changes in user behavior or ability and adjusts its presentation or functionality accordingly, without requiring the user to manually configure settings. In accessibility, adaptive user interfaces can monitor pointing performance…

Adaptive User Interface(also: AUI, Adaptive Interface, Self-Adapting Interface)

A user interface that automatically adjusts its presentation, behavior, or content based on user characteristics, preferences, context, or interaction patterns. Unlike customizable interfaces where users manually configure settings, adaptive interfaces use algorithms to detect…

Adaptive content(also: Content adaptation, Adaptive hypermedia)

Content that automatically adjusts its presentation, structure, or level of detail based on the needs, preferences, or capabilities of the user or their device. In accessibility, adaptive content goes beyond responsive design (which adjusts layout) to potentially restructure…

Adaptive content complexity(also: Layered descriptions, Tiered content)

A design strategy that provides the same information at multiple levels of detail or complexity, allowing users to access content appropriate to their cognitive processing capacity, prior knowledge, or current needs. For example, a system might offer simple, medium, and detailed…

Adaptive interface(also: Adaptive UI, Self-adapting interface)

A user interface that automatically adjusts its parameters — such as target sizes, input methods, timing, layout, or interaction modalities — in response to detected changes in the user's abilities, context, or preferences. Adaptive interfaces are a key implementation strategy…

Adherence(also: Treatment Adherence, Exercise Adherence, Compliance)

The extent to which a person follows prescribed medical treatments, exercise routines, or therapy programs. In physical therapy and rehabilitation, adherence is often framed as an individual responsibility, with non-adherence viewed as patient failure. However, accessibility…

Administrative Burden(also: Bureaucratic Burden, Process Burden)

The cumulative effort, time, stress, and negative impacts that result from navigating administrative processes such as applying for benefits, gaining medical evidence, completing forms, and interacting with multiple organisations to achieve a particular goal. For disabled…

Adobe Acrobat(also: Acrobat Pro, Adobe Acrobat Pro, Acrobat DC)

Adobe's commercial software suite for creating, editing, and managing PDF documents, including accessibility remediation features. Acrobat Pro includes tools for adding tags to PDF documents, setting reading order, editing document structure through a tag tree, running…

Adobe Flash(also: Flash Player, Flash, Macromedia Flash)

A discontinued multimedia software platform formerly used to create animations, rich internet applications, games, and video players embedded in web pages. Flash content was notoriously inaccessible to screen readers and other assistive technologies because the Flash Player…

Adult ADHD Self-Report Scale(also: ASRS, ASRS-v1.1, Adult ADHD Self-Rating Scale)

A short self-report screening instrument for adult Attention-Deficit/Hyperactivity Disorder developed by the World Health Organization in collaboration with researchers from Harvard Medical School. The most widely used version, ASRS-v1.1, is an 18-item questionnaire whose first…