Glossary

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Morphological NMS(also: Morphological Non-Manual Sign)

Non-manual signs that modify or add grammatical meaning to manual signs, functioning similarly to morphemes in spoken languages. In ASL, morphological NMS convey information about degree, intensity, size, and manner. For example, facial expressions and body posture can show…

Morse Code(also: Morse Code Input)

A communication system that encodes text characters as sequences of short signals (dots) and long signals (dashes). Originally developed for telegraphy, Morse code has found significant application in assistive technology as an alternative text input method for people with…

Motion Capture(also: MoCap, Movement Tracking)

Technology that records the movements of people or objects, typically using cameras, sensors, or computer vision, and translates them into digital data for animation or analysis. In sign language applications, motion capture tracks hand, body, and facial movements to drive…

Motion Design(also: Motion Graphics, Motion-Driven Design)

The practice of animating graphic elements - text, icons, diagrams, captions - in time-based media to communicate instructional content. In accessible educational video, motion design is used to guide visual attention, sequence information, and pace the presentation of captions…

Motion Gaming(also: Motion-Based Gaming, Gesture-Based Gaming)

Video games that use body movements as input, typically through motion-sensing controllers (Nintendo Wii) or depth cameras (Microsoft Kinect) rather than traditional button-based controllers. Motion gaming has significant applications in rehabilitation, where it can make…

Motion History Image(also: MHI)

A computer vision technique that represents motion in video sequences as a single grayscale image, where pixel intensity indicates recency of movement. Brighter pixels represent more recent motion while darker pixels show older movement patterns. In accessibility applications,…

Motion Impairment(also: Motor Impairment, Physical Impairment, Mobility Impairment)

A condition that limits a person's ability to control voluntary physical movement, affecting fine or gross motor skills, strength, coordination, or range of motion. Motion impairments may result from conditions such as cerebral palsy, muscular dystrophy, spinal cord injury,…

Motion Sensor(also: Motion Detection, Gesture Sensor)

A device that detects physical movement in its environment, often by tracking body position, joint angles, or gestures. In accessibility and assistive technology, motion sensors enable touchless interaction, gesture-based interfaces, and movement-tracking rehabilitation systems.…

Motion Sickness(also: Cybersickness, Simulator Sickness, VR Sickness)

A condition characterized by nausea, disorientation, and discomfort experienced when using virtual reality, simulators, or viewing motion-heavy content. In VR accessibility, motion sickness disproportionately affects some users and must be considered in interface design.…

Motion Tracking(also: Motion Capture, MoCap, Body Tracking)

Technology that records and analyses the movement of people or objects in real time, typically using cameras, sensors, or wearable devices to capture position, orientation, and velocity data. In accessibility applications, motion tracking enables systems to compare a user's body…

Motion capture(also: Mocap)

The process of recording the movement of objects or people, typically using optical systems with reflective markers, depth cameras, or body-worn sensors. Motion capture is used in accessibility research to create ground-truth datasets for developing assistive body-tracking…

Motion-Based AAC(also: Physical Expressive AAC, Expressive Sidekick)

An emerging form of augmentative and alternative communication that uses physical movement of objects or robotic devices to convey nonverbal communicative intent during conversations. Unlike traditional AAC which focuses on generating speech, motion-based AAC addresses the…

Motion-based game accessibility(also: Movement game accessibility, Exergame accessibility)

The design and adaptation of video games that use physical movement as the primary input — such as Kinect, Wii, and VR games — to be playable by people with motor impairments including wheelchair users. Commercial motion-based games typically assume standing play and full-body…

Motor Accessibility(also: Physical Accessibility, Motor Impairment Accessibility)

Motor accessibility refers to the design of digital systems and interfaces to be operable by people with physical disabilities affecting movement, strength, coordination, or fine motor control. Relevant conditions include cerebral palsy, muscular dystrophy, spinal cord injury,…

Motor Coordination(also: Movement Coordination, Coordination)

The ability to integrate sensory information and muscle movements to perform smooth, accurate, and controlled physical actions. Motor coordination encompasses both gross motor skills (large body movements like walking) and fine motor skills (precise hand and finger movements).…

Motor Cortex(also: Primary Motor Cortex, M1)

The region of the cerebral cortex responsible for planning, controlling, and executing voluntary movements. Located in the frontal lobe along the precentral gyrus, the motor cortex is organised somatotopically — different areas control different body parts. In brain-computer…

Motor Disability(also: Motor Impairment, Physical Disability, Mobility Impairment)

A disability that affects a persons ability to control movement, including fine motor skills like gripping and manipulating objects, and gross motor skills like walking and reaching. Motor disabilities can result from conditions affecting muscles, nerves, bones, or the brain.…

Motor Disability(also: Motor Impairment, Physical Disability, Movement Disorder)

A condition that affects a person's ability to control voluntary muscle movements, impacting mobility, dexterity, coordination, or speech production. Motor disabilities can result from neurological conditions (cerebral palsy, ALS, multiple sclerosis), spinal cord injuries,…

Motor Fluctuation(also: On-Off Phenomenon, Wearing Off, On-Off Periods)

Variations in motor function experienced by people with Parkinson's Disease, typically related to medication timing. During 'on' periods when medication is working optimally, motor symptoms are controlled; during 'off' periods as medication wears off, symptoms like tremor,…

Motor Function Time(also: Motor Response Time, Motor Cycle Time)

The time required to execute a physical action such as pressing or releasing a key, clicking a mouse button, or moving a pointing device. In the Model Human Processor, motor function time for able-bodied users averages approximately 70 milliseconds per action. For motor-impaired…

Motor Imagery(also: MI, Mental Practice, Imagined Movement)

The mental rehearsal or imagination of physical movement without actual motor execution. In brain-computer interfaces, motor imagery typically involves imagining left-hand or right-hand movements, which produce distinct patterns in the sensorimotor cortex that can be detected…

Motor Impairment(also: Motor Disability, Physical Disability, Movement Impairment)

A condition that affects a person ability to control physical movements, including fine motor skills (small precise movements like typing) and gross motor skills (larger movements like reaching). Motor impairments can result from conditions such as cerebral palsy, muscular…

Motor Impairment(also: Motor Disability, Physical Impairment, Movement Disorder)

A condition that affects a person's ability to control physical movements, including fine motor skills (precise movements of hands and fingers) and gross motor skills (larger movements involving arms, legs, and trunk). Motor impairments can result from conditions such as stroke,…

Motor Learning(also: Motor Skill Acquisition)

The process by which practice and experience lead to relatively permanent changes in the capability to perform motor skills. In speech therapy, motor learning principles guide treatment design: random presentation order of stimuli, variable practice contexts for each target…

Motor Neuron Disease(also: MND, ALS, Amyotrophic Lateral Sclerosis)

A group of progressive neurological disorders that destroy motor neurons, the cells controlling voluntary muscle activity including speaking, walking, breathing, and swallowing. ALS (amyotrophic lateral sclerosis) is the most common form. As the disease progresses, people lose…

Motor Recovery(also: Motor Rehabilitation, Motor Function Recovery)

The process of regaining voluntary movement control and physical function after neurological injury such as stroke, traumatic brain injury, or spinal cord damage. Motor recovery involves reorganization of neural pathways through cortical plasticity, where undamaged areas of the…

Motor Skill(also: Motor Skills, Gross Motor Skill, Fine Motor Skill)

A motor skill is a learned ability to produce a coordinated movement of muscles to achieve an outcome, ranging from gross-motor actions like walking, jumping, and balancing to fine-motor actions like handwriting, buttoning a shirt, or manipulating a stylus. Motor skills strongly…

Motor Skills(also: Motor Abilities, Motor Function)

The learned abilities to perform movements with accuracy, speed, and coordination. Motor skills are typically divided into gross motor skills (large muscle movements like walking, jumping, balance) and fine motor skills (small muscle movements like writing, grasping, buttoning).…

Motor ability(also: Motor function, Motor capacity)

The capacity to perform physical movements required for interaction with technology and the environment, encompassing sub-constructs including strength, dexterity, coordination, range of motion, speed, accuracy, endurance, and tremor control. Motor ability is not a fixed trait…

Motor control(also: Motor coordination, Movement control)

The process by which the nervous system coordinates muscles and limbs to produce purposeful, accurate movement. Motor control involves planning movements, executing them, and using sensory feedback to make real-time corrections. Impairments in motor control — caused by…

Motor speech disorder(also: MSD)

A category of speech disorders caused by neurological impairments affecting the motor planning, programming, or execution of speech movements. Motor speech disorders include dysarthria (muscle weakness or paralysis) and apraxia of speech (difficulty coordinating voluntary speech…

Mouse(also: Computer Mouse, Optical Mouse)

A mouse is a hand-operated pointing device that translates relative motion across a flat surface into movement of an on-screen cursor, with one or more buttons and usually a scroll wheel for selection and additional commands. It is the dominant pointing device for desktop…

Mouse Alternative(also: Alternative Pointing Device, Mouse Replacement)

A mouse alternative is any input device or technique that lets a user perform pointer-control tasks — moving a cursor, clicking, dragging, selecting — without using a conventional mouse. For people with motor impairments, mouse alternatives include trackballs, head-pointer and…

Mouse Emulation(also: Mouse Simulation, Virtual Mouse)

Software or hardware that simulates mouse pointer movement, clicks, and other mouse actions using alternative input methods such as head tracking, eye gaze, joysticks, switch scanning, keyboard commands, or biosignal interfaces. Mouse emulation enables people who cannot use a…

Mouse Pointer(also: Cursor, Screen Pointer, Onscreen Pointer)

The small graphical indicator on a computer screen that represents the position of a pointing device such as a mouse, trackpad, or stylus. The mouse pointer is used to identify and interact with interface elements in graphical user interfaces through pointing, clicking, and…

Mouth Interface(also: Mouth-operated interface, Mouth-based input)

An input modality that uses mouth movements - tongue position, cheek puffs, jaw motion, lip gestures, breath, or sip-and-puff - to control a computer, wheelchair, or XR system. Mouth interfaces serve people with limited upper-limb mobility (e.g., spinal cord injury, muscular…

Mouth Joystick(also: Lip Joystick, Mouth-Operated Joystick)

An assistive input device controlled by the user's mouth, lips, or tongue that functions as a pointer or gamepad joystick. The user moves a small stick held between the lips to direct cursor or on-screen movement; selection is typically triggered by a sip-and-puff switch, chin…

Mouth Morphemes(also: Mouth Gestures, Mouthing (ASL), Adverbial Mouth Morphemes)

Non-manual mouth configurations in sign languages that carry grammatical or adverbial meaning independent of the words they accompany. In American Sign Language, mouth morphemes include patterns such as "mm" (relaxed, normal), "cha" (large), "oo" (small or close), "th" (careless…

Mouthing(also: Mouth Patterns)

In sign language, mouthing refers to the mouth movements that accompany manual signs, typically derived from the spoken language of the surrounding hearing community. For example, a signer using German Sign Language (DGS) may mouth the German word while simultaneously producing…

Movement Disorder(also: Motor Disorder)

A group of neurological conditions that affect the speed, fluency, quality, and ease of movement. Movement disorders can cause excessive or reduced movement that may or may not be voluntary. Common types include Parkinson's disease, essential tremor, dystonia, and Huntington's…

Movement Sonification(also: Motion Sonification)

The practice of mapping qualities of physical movement - such as speed, direction, duration, or weight - to non-verbal sound cues so that movement can be perceived auditorily. In accessibility contexts, movement sonification can convey information about body motion to blind and…

Mu Rhythm(also: Mu Wave, Mu Oscillation)

A pattern of electrical brain activity oscillating at approximately 8-12 Hz, recorded over the sensorimotor cortex. Mu rhythms are suppressed (desynchronised) when a person performs or imagines performing a movement, a phenomenon known as event-related desynchronisation. In…

Multi-Factor Authentication(also: MFA, 2FA, Two-Factor Authentication)

An authentication pattern that requires two or more verification factors — something you know (password), have (phone, token), or are (biometric) — to confirm a user's identity. MFA substantially reduces account compromise from stolen passwords. Accessibility considerations…

Multi-Fidelity Modeling(also: Multi-Fidelity Tactile Materials)

A design strategy that provides tactile representations at multiple levels of detail and complexity to support layered learning and comprehension. In accessible museum and educational contexts, this means offering simplified low-fidelity models (like 2D silhouettes or outline…

Multi-Grade Classroom(also: Multi-Grade Teaching, Combined Classroom)

A classroom setting where a single teacher instructs students from multiple grade levels simultaneously. Multi-grade classrooms are common in schools for the blind in India, where teacher shortages require TVIs to manage students across an average of 6.5 grade levels (some…

Multi-Layered Interface(also: ML Interface, Layered Interface, Training Wheels Interface)

An interface design approach where novice users start with a reduced-functionality layer containing only basic features, then progress to more complex layers as they become comfortable. This technique reduces cognitive load during initial learning by limiting the number of…

Multi-Modal(also: Multi-Modality, Multimodal Interaction)

An approach to presenting information or enabling interaction through multiple sensory channels simultaneously, such as combining visual, auditory, and tactile outputs. In accessibility, multi-modal design is particularly valuable because it allows users to access information…

Multi-Modal Communication(also: Multimodal Communication)

Communication that simultaneously uses multiple channels or modes—such as speech, gesture, facial expression, gaze, device output, and body movement—to convey meaning. AAC users are inherently multi-modal communicators, blending whatever channels are available to them to create…

Multi-Modal LLM(also: Multimodal Large Language Model, MLLM, Vision-Language Model)

A large language model that can process and reason over more than one type of input modality, typically text combined with images, audio, or video. In accessibility research, multi-modal LLMs such as GPT-4o, CLIP, and BLIP-2 are increasingly used to analyse screenshots of web…

Multi-Model Comparison(also: Cross-Model Comparison, Ensemble Verification)

The practice of generating responses from multiple AI models for the same input and comparing their outputs to assess reliability, identify errors, and provide a more comprehensive understanding of the content. In accessibility contexts, multi-model comparison is used to help…