Glossary

Search results

Alternative Input Method(also: Alternative Input, Non-Standard Input)

Any method of providing input to a computer or device that differs from the conventional keyboard, mouse, and touchscreen interfaces. Alternative input methods are essential for people with motor, sensory, or cognitive disabilities who cannot use standard input devices…

Area Pointing(also: Point and Click, Mouse Pointing)

Area pointing is the conventional target-acquisition paradigm in graphical user interfaces, in which the user must move a cursor inside a confined two-dimensional target region and then execute a click (or equivalent dwell, tap, or activation action) to select it. Targets such…

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…

Auto-Correction(also: Autocorrect, Automatic error correction, Spell correction)

A software feature that automatically detects and corrects typing errors, typically by comparing entered text against a dictionary and suggesting or applying the closest match based on string distance algorithms. Auto-correction is particularly important for accessible text…

Back Tap(also: Back Tap Gesture)

An iOS accessibility feature that allows users to trigger actions by tapping on the back of their iPhone two or three times. Back Tap can be configured to activate shortcuts, accessibility features, or system functions without requiring precise touchscreen interaction. For…

Bimanual Interaction(also: Two-Handed Interaction)

Interaction techniques in computing and VR that require the coordinated use of both hands simultaneously, such as holding two controllers, performing gestures with both hands, or operating dual joysticks. Bimanual interaction presents significant accessibility barriers for users…

Biometric Control(also: Biometric Input, Physiological Control Interface)

The use of measurable biological signals from the human body — such as brain waves (EEG), skin conductance (galvanic skin response), muscle electrical activity (EMG), heart rate, or eye movements — as input channels for controlling computers and assistive technology devices.…

Braille Input(also: Braille Keyboard Input, Braille Screen Input)

A text entry method that allows users to type characters using Braille code on a device, rather than a standard QWERTY keyboard. On touchscreen devices, Braille input typically maps finger taps or gestures to the six dots of a Braille cell, enabling blind users who know Braille…

Brain-Computer Interface(also: BCI, Brain-Machine Interface, BMI)

A technology that enables direct communication between the brain and an external device by detecting and interpreting neural activity, typically through electroencephalography (EEG) or electromyography (EMG). In accessibility contexts, BCIs allow people with severe motor…

Brain-Computer Interface(also: BCI, Brain-Machine Interface, BMI)

A direct communication pathway between the brain and an external device that enables users to control computers, prosthetics, or other systems using neural signals rather than physical movement. BCIs are particularly significant for people with severe motor impairments such as…

Brain-Computer Interface(also: BCI, Brain-Machine Interface, BMI)

A technology that enables direct communication between the brain and an external device by detecting and interpreting neural signals. BCIs can use invasive methods (implanted electrodes) or non-invasive approaches (EEG headsets). In accessibility contexts, BCIs allow people with…

Breath Control(also: Sip-and-Puff Control, Pneumatic Input)

An assistive technology input method that uses breath pressure — blowing or sipping through a sensor — to control a computer, device, or instrument. Breath control is particularly valuable for individuals with severe motor disabilities who retain respiratory function, such as…

Breathing Input(also: Breath-based Input, Puff Input)

An alternative computer input method that uses deliberate breath actions — such as puffing, blowing, or inhaling — detected by a microphone or pressure sensor as control signals for navigating interfaces and selecting items. Breathing input is designed for people with severe…

Bubble Cursor(also: Dynamic Cursor, Area Cursor)

An enhanced pointing technique that dynamically resizes the cursor's activation area to make target selection easier, particularly for users with motor impairments. The bubble cursor expands to encompass the nearest target, effectively enlarging the clickable region without…

Camera Mouse(also: Head-Controlled Mouse Pointer, Head Tracking Mouse)

A computer-vision-based mouse-replacement system that tracks a user's head motion through a standard webcam to control the mouse pointer on screen. Developed at Boston University by Margrit Betke and James Gips, Camera Mouse is freely available and enables people with severe…

Chairable Technology(also: Chairable Input, Chairable Devices)

Input devices and interactive technologies designed to integrate with the form of a wheelchair, analogous to how wearable technology fits with an individual's clothing. Chairable technology recognises that power wheelchair users spend most of their waking hours in their chairs…

Chord Entry(also: Chording, Chord Input, Chordal Input)

A method of text input where multiple keys are pressed simultaneously to produce a single character, rather than pressing keys sequentially. In braille keyboards such as the Perkins Brailler, chord entry involves pressing combinations of six keys at once to represent different…

Click-Time Distribution(also: Timing Profile, Click Precision)

A statistical model of when a switch user activates their switch relative to a target timing event, used to characterize the precision and consistency of a user's motor control. In the Nomon interface, the click-time distribution measures how accurately a user clicks when a…

Click-on-Lift(also: Lift-off Activation, Release Activation)

An interaction technique where a touch target is activated only when the user lifts their finger from the screen while still within the target area, rather than registering the action at the point of initial contact. This approach is particularly beneficial for users with hand…

Clutching(also: Clutch Mechanism, Clutch Gesture)

In gesture- and motion-based input systems, a mechanism that lets the user temporarily disengage the recogniser so that everyday, non-communicative movements — reaching, adjusting posture, gesturing socially — do not trigger false activations. Named after the mechanical clutch…

Command Recognition(also: Command Classification, Input Recognition)

The process by which a computer system interprets and classifies a user's input action — such as a gesture, voice command, or key press — as a specific intended command from a predefined vocabulary of possible commands. The accuracy of command recognition is characterised by the…

Connected Speech Recognition(also: Continuous Speech Recognition)

A form of automatic speech recognition in which users speak words naturally, with normal coarticulation and minimal pauses, rather than pausing between each word as required by older 'discrete' or 'isolated-word' recognisers. Connected-speech recognition was a significant…

Continuous Voice Control(also: Continuous Vocal Control, Proportional Voice Control)

A voice interaction paradigm in which vocal parameters such as pitch, loudness, vowel quality, and timbre are used to provide smooth, proportional, real-time control of a system, as opposed to discrete voice commands that trigger specific actions. Continuous voice control is…

Curse of Dimensionality (Accessibility)

In an accessibility context, the practical barrier that arises when a player or user must coordinate a large number of distinct inputs simultaneously or in rapid succession — for example, moving, aiming, shooting, and reloading concurrently in a first-person shooter. Even when…

Cursor Control(also: Pointer Control, Cursor Navigation)

The ability to direct and position an on-screen cursor or pointer using an input device such as a mouse, trackball, touchpad, joystick, or eye tracker. Cursor control is a fundamental requirement for interacting with graphical user interfaces and involves both gross movements…

Cursor Deviation(also: Cursor Drift, Path Deviation)

The difference between the actual path taken by a cursor and the ideal straight-line path between the starting point and the target. Cursor deviation is a key performance metric in evaluating alternative input devices such as head controls, eye trackers, and adapted mice. Higher…

Cursor Movement(also: Cursor Navigation, Pointer Movement, Mouse Movement)

The process of controlling the position of a pointer or cursor on screen using an input device such as a mouse, trackpad, or joystick. Cursor movement efficiency is a key metric in accessibility research, measured through movement time, velocity, and path directness. Users with…

DTMF(also: Dual-Tone Multi-Frequency, Touch-Tone)

DTMF (Dual-Tone Multi-Frequency) is the signaling system used when pressing keys on a telephone keypad, where each key press generates a unique combination of two audio frequencies. In accessibility contexts, DTMF input serves as an alternative interaction method for voice-based…

Dead Time(also: Wait Time, Idle Time)

In scanning-based assistive technology interfaces, the period during which a user must passively wait before they can make their next input action. In row-column scanning, dead time occurs while waiting for the desired row or column to be highlighted. Longer dead times reduce…

Debounce(also: Debounce Filter, Key Debounce, Bounce Key Filter)

A keyboard accessibility feature that filters out unintended extra keypresses caused by tremor or imprecise motor control. When enabled, the system ignores rapid successive activations of the same key within a specified time window, treating them as a single press. Debounce is…

Deformable Input(also: Flexible Input Surface)

An input method that uses physically flexible or pressure-sensitive surfaces that can be bent, squeezed, twisted, or otherwise deformed to generate control signals. Deformable input devices can provide accessible interaction for users with motor impairments, as they may require…

Digital Crown(also: Watch Crown, Rotary Input)

A physical rotary input control on the Apple Watch and some other smartwatches that can be turned to scroll, navigate, or adjust values. The digital crown provides tactile, proportional input that does not require looking at a screen, making it valuable for accessibility…

Direction-Based Navigation(also: Directional Navigation, Direction-Based Cursor Control)

A cursor control method where users issue directional commands such as "move left," "move up," or "move down" to reposition the cursor on screen. In speech-based implementations, these commands move the cursor continuously or in fixed increments. Direction-based navigation is…

Disambiguation(also: Target Disambiguation, Touch Disambiguation)

In accessible interface design, disambiguation is the process of resolving ambiguity when a user's input could correspond to more than one interactive target. This commonly occurs on touchscreens where small, densely packed elements make precise selection difficult, particularly…

Drag and Drop(also: DnD)

An interaction pattern in which users select an on-screen object by pressing and holding, then move it to a new location before releasing. Drag and drop is widely used in visual programming environments, file management, and content editing. It presents significant accessibility…

Dwell Activation(also: Dwell Click, Dwell Selection)

An input method where an action is triggered by maintaining focus on a target for a specified period of time (the dwell time). Commonly used with eye tracking and head tracking systems, dwell activation allows users to select items without needing to physically click. While…

Dwell Control(also: Dwell Click, Dwell Selection, Dwell-Time Activation)

An input method in which a user activates a target — such as a button, link, or key — by holding a pointer or gaze over it for a specified period of time rather than clicking or tapping. Dwell control is essential for users who interact via head tracking, eye tracking, or other…

Dwell Selection(also: Dwell Click, Dwell Time Selection, Hover Click)

An interaction technique where a user activates or selects an on-screen element by keeping a cursor, gaze point, or pointer within the target area for a specified duration (the dwell time), rather than clicking or tapping. Dwell selection is essential for people with motor…

Dwell Time(also: Gaze Dwell, Fixation Duration)

The length of time a user must maintain their gaze on a target element to trigger a selection in eye gaze technology systems. Dwell time is a critical parameter in gaze-based interfaces: too short and users make unintended selections (the "Midas touch" problem), too long and…

Dynamic Keyboard(also: Adaptive Keyboard, Self-Adjusting Keyboard)

An assistive technology concept in which a keyboard automatically adjusts its input parameters — such as key repeat rate, debounce time, and acceptance delay — based on the user's typing patterns and abilities. Dynamic keyboards were developed to reduce common typing errors…

EdgeWrite(also: Edge Write)

A gestural text entry method that uses the physical edges and corners of a square input area to guide character formation. Unlike traditional handwriting recognition that analyzes the full path of a stroke, EdgeWrite recognizes characters based on the sequence of corners hit,…

Electromagnetic Tracking(also: Magnetic Tracking, 6-DOF Tracking)

Electromagnetic tracking is a position and orientation sensing technology that uses electromagnetic fields to determine the location and rotation of a sensor in three-dimensional space. Systems like the Polhemus tracker generate a low-frequency magnetic field from a stationary…

Electromyography(also: EMG, Electromyogram)

Electromyography (EMG) is a technique for measuring the electrical activity produced by muscles when they contract or are at rest. In accessibility and assistive technology, EMG sensors placed on the skin can detect muscle activations even when there is no visible movement,…

Enhanced Area Touch(also: Area Touch, Expanded Touch Area)

A touchscreen interaction technique that enlarges the effective touch point from a single pixel to a larger circular area, expanding both the motor space (the physical area the user needs to target) and the visual space (the on-screen representation of targets). When multiple…

Eye Cursor(also: Gaze Cursor)

A visual indicator displayed on screen that shows where an eye tracking system has determined the user is currently looking. The eye cursor serves the same function as a mouse cursor but is controlled by eye gaze rather than hand movement. Because eye gaze is inherently less…

Eye Gaze(also: Gaze, Gaze Direction, Visual Gaze)

The direction and focus of a person's eyes during visual attention, used both as a communication signal and as a measurable indicator of cognitive processing. In sign language communication, eye gaze serves critical linguistic functions including marking grammatical…

Eye Gaze Communication(also: Gaze-Based Communication, Eye Tracking Communication)

The use of eye movements and gaze direction as a means of communication, either naturally (making eye contact, looking at objects to indicate interest) or through technology (eye-tracking systems that allow users to select items on a screen by looking at them). For AAC users,…

Eye Gaze Technology(also: Eye Control Technology, Gaze Control)

Technology that tracks and responds to eye movements, enabling users to control electronic devices using only their eyes. Eye gaze technology typically uses infrared cameras to track pupil position and gaze direction, allowing users to move cursors, make selections, type text,…

Eye Tracking(also: Gaze Tracking)

Technology that detects and follows the movement of a user's eyes, enabling gaze-based interaction, attention monitoring, and foveated rendering. In accessibility contexts, eye tracking serves as an alternative input method for users who cannot use traditional controllers,…

Eye-Gaze Control(also: Gaze Control, Eye-Controlled Interface, Gaze-Based Input)

An input method that uses eye-tracking technology to detect where a user is looking and translates gaze direction into control commands for computers, wheelchairs, communication devices, and other systems. Eye-gaze control is essential for people with severe motor disabilities —…