Glossary

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Akinesia(also: Poverty of Movement)

The loss or impairment of the ability to initiate voluntary movement, distinct from muscle weakness or paralysis. In Parkinson's Disease, akinesia manifests as difficulty starting movements, reduced spontaneous movements like blinking or arm swing while walking, and a mask-like…

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…

Becker Muscular Dystrophy(also: BMD)

A genetic neuromuscular disorder caused by mutations in the dystrophin gene on the X chromosome, resulting in progressive muscle weakness and wasting. Becker Muscular Dystrophy is similar to Duchenne Muscular Dystrophy but generally has a later onset (typically in the teens or…

Cueing(also: External Cueing, Sensory Cueing)

In rehabilitation, cueing is the delivery of external sensory stimuli - visual, auditory, or somatosensory - that guide or trigger a motor action. Cueing is used most prominently in Parkinson's disease, where basal ganglia dysfunction impairs internally generated movement…

Drop Foot(also: Foot Drop, Peroneal Nerve Palsy)

A condition characterized by difficulty lifting the front part of the foot, causing the toes to drag along the ground during walking. Drop foot is not a disease itself but a symptom of an underlying neurological, muscular, or anatomical problem, commonly caused by nerve injury…

Duchenne Muscular Dystrophy(also: DMD, Duchenne MD)

Duchenne Muscular Dystrophy (DMD) is a severe genetic disorder characterized by progressive muscle degeneration and weakness, caused by mutations in the dystrophin gene on the X chromosome. It primarily affects boys, with symptoms typically appearing between ages 2-5 and…

Dyspraxia(also: Developmental Coordination Disorder, DCD)

A neurodevelopmental condition affecting motor planning, coordination, and the sequencing of movements. People with dyspraxia have difficulty translating intended actions into coordinated physical movements, despite having adequate muscle strength and understanding of what they…

Dystonia(also: Dystonic Movements)

A movement disorder characterized by sustained or intermittent muscle contractions causing abnormal, often repetitive movements, postures, or both. Dystonia can affect a single body part (focal dystonia), adjacent regions (segmental), or the whole body (generalized). In…

Electronic Assistive Technology(also: EAT, Electronic AT)

Computer-based devices and systems that enable people with severe disabilities to perform tasks they would otherwise be unable to accomplish, including communication, environmental control, mobility, and computer access. Electronic assistive technologies are often integrated…

Exoskeleton(also: Robotic Exoskeleton, Wearable Exoskeleton)

A wearable mechanical or robotic device that fits around a part of the body — typically the hand, arm, or leg — and provides powered movement assistance, resistance, or guided motion. In rehabilitation contexts, exoskeletons are used to support intensive, repetitive motor…

Facial Palsy(also: Bell's Palsy, Facial Paralysis, Unilateral Facial Palsy)

Facial palsy is a condition involving weakness or paralysis of the facial muscles, typically caused by damage to the facial nerve (cranial nerve VII). Bell's palsy is the most common form, appearing suddenly and usually affecting one side of the face. Facial palsy can…

Gait Training(also: Gait Rehabilitation)

Gait training is therapeutic practice aimed at improving walking function - velocity, stride length, symmetry, stability, and cadence - in people with neurological or musculoskeletal impairments. It is central to rehabilitation after stroke, spinal cord injury, and lower-limb…

Gross Motor Function Classification System(also: GMFCS)

A standardized five-level classification system used to describe the gross motor function of children with cerebral palsy, based on self-initiated movement with emphasis on sitting, walking, and mobility. Level I indicates the highest function (walking without limitations),…

Gross Motor Movement(also: Gross Motor Skills, Gross Motor Control)

Large body movements involving the major muscle groups of the arms, legs, and torso, as opposed to fine motor movements that require precise control of small muscles in the fingers and hands. In assistive technology, the distinction between gross and fine motor abilities is…

Intention Tremor(also: Cerebellar Tremor, Action Tremor)

A type of tremor that appears or worsens during voluntary, goal-directed movement — particularly as a limb approaches its target — and is typically absent at rest. Intention tremor is most often caused by damage to the cerebellum or its pathways (multiple sclerosis, stroke,…

Micrographia(also: Small Handwriting)

A condition characterized by abnormally small, cramped handwriting that often becomes progressively smaller within a line or paragraph. Micrographia is a common early sign of Parkinson's Disease, resulting from the same motor control difficulties that cause bradykinesia. The…

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 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…

Multimodal Cueing

Multimodal cueing is the simultaneous or selectable use of two or more sensory channels - typically visual, auditory, and somatosensory (vibrotactile) - to guide motor behaviour during rehabilitation or assistive interaction. The rationale is that different modalities engage…

Muscular Dystrophy(also: MD)

A group of inherited genetic conditions that cause progressive weakness and loss of muscle mass, affecting mobility, upper limb function, and in some forms, respiratory and cardiac function. People with muscular dystrophy often rely on electric wheelchairs for mobility and may…

Muscular Dystrophy(also: MD)

A group of inherited genetic conditions that cause progressive weakness and degeneration of skeletal muscles, the muscles that control movement. There are many types of muscular dystrophy varying in severity, age of onset, and which muscles are affected. Because muscular…

Myopathy(also: Muscle Disease)

A group of disorders affecting skeletal muscle function, characterized by muscle weakness, cramping, stiffness, or wasting. Myopathies can be inherited (muscular dystrophies) or acquired (inflammatory myopathies, metabolic myopathies). For digital accessibility, people with…

Neuromuscular Disease(also: Neuromuscular Disorder, NMD)

A broad category of conditions that affect the nerves controlling voluntary muscles, the muscles themselves, or the communication between nerves and muscles. Neuromuscular diseases include muscular dystrophies, motor neurone disease (ALS), spinal muscular atrophy, myasthenia…

Neuromuscular Disorders(also: Neuromuscular Diseases, NMDs)

A broad group of medical conditions that impair the functioning of muscles, either through direct pathology of the muscle tissue, the peripheral nerves that control them, or the neuromuscular junction where nerves connect to muscles. Neuromuscular disorders include amyotrophic…

Oral Motor Impairment(also: Oral-Motor Dysfunction, Oromotor Impairment)

A condition affecting the muscles and movements of the mouth, jaw, lips, and tongue that are involved in speech production, feeding, and swallowing. Oral motor impairments can result from neurological conditions such as cerebral palsy, stroke, or traumatic brain injury, and may…

Orthotics(also: Orthosis, Orthoses, Orthotic Device)

Externally applied devices used to modify the structural and functional characteristics of the neuromuscular and skeletal systems — including braces, splints, and supports for the spine, limbs, hands, feet, and neck. Orthoses stabilize joints, correct alignment, redistribute…

Osteoarthritis(also: OA, Degenerative Joint Disease)

The most common form of arthritis, caused by progressive breakdown of the cartilage that cushions the ends of bones. Osteoarthritis produces joint pain, stiffness, swelling, and reduced range of motion, most often in the hands, knees, hips, and spine. For digital accessibility,…

Overlap Error(also: Key Overlap Error, Simultaneous Key Press Error)

A typing error that occurs when two keys are pressed down at the same time, typically when a finger accidentally activates an adjacent key while moving toward the intended key, or when a user's hand rests on a key unintentionally. Overlap errors are particularly common among…

Paralysis(also: Paralyzed, Paresis)

The partial or complete loss of voluntary muscle function, resulting from damage to the motor nervous system. Common causes include spinal cord injury, stroke, traumatic brain injury, motor neuron diseases such as ALS, multiple sclerosis, cerebral palsy, and brainstem lesions…

Paresis(also: Partial Paralysis)

A partial loss of voluntary muscle movement, distinguished from full paralysis (plegia). Paresis can affect a single limb (monoparesis), one side of the body (hemiparesis), or all four limbs (tetraparesis), and may result from stroke, cerebral palsy, spinal cord injury, or…

People with Severe Motor Disabilities(also: PSMD)

A term used in assistive technology and human-robot interaction research to describe individuals whose motor impairments are severe enough that they cannot reliably use their hands or arms for everyday tasks, and who therefore depend on hands-free control modalities such as eye…

Primary Lateral Sclerosis(also: PLS)

A rare progressive neurological disease affecting the upper motor neurons, causing weakness and stiffness in the voluntary muscles, particularly in the legs, arms, and tongue. Unlike amyotrophic lateral sclerosis (ALS), PLS progresses more slowly and primarily affects upper…

Reach Envelope(also: Workspace Envelope, Reach Zone, Comfort Zone)

The three-dimensional volume of space that a person can physically access with their hands or arms from a given position, taking into account their specific motor abilities, range of motion, and comfort levels. For people with upper extremity mobility impairments — such as those…

Repetitive Stress Injury(also: RSI, Repetitive Strain Injury, Repetitive Motion Injury)

A group of conditions caused by repetitive movements, forceful exertions, or sustained awkward postures over extended periods, resulting in damage to muscles, tendons, nerves, or other soft tissues. In computing contexts, RSI commonly affects the hands, wrists, arms, shoulders,…

Rigidity(also: Muscle Rigidity, Stiffness)

Increased muscle tone causing stiffness and resistance to passive movement, commonly experienced in Parkinson's Disease and other neurological conditions. Unlike spasticity (which varies with movement speed), rigidity is constant throughout the range of motion. Rigidity affects…

Sensory Based Motor Disorder(also: SBMD)

A subtype of Sensory Processing Disorder in which the brain has difficulty using sensory information to plan and execute motor actions. SBMD encompasses two sub-types: postural disorder, which affects balance and core stability, and dyspraxia, which impacts motor planning and…

Spasm(also: Muscle Spasm, Spasticity)

A sudden, involuntary contraction of a muscle or group of muscles that can cause uncontrolled movement or a temporary inability to move. Spasms are common in conditions such as cerebral palsy, spinal cord injury, and multiple sclerosis. In the context of computer accessibility,…

Spastic Cerebral Palsy(also: Spastic CP)

The most common subtype of cerebral palsy, characterised by stiff or tight muscles (hypertonia) and exaggerated reflexes, caused by damage to the motor cortex or corticospinal tracts of the developing brain. Subtypes are further classified by the limbs affected (diplegia,…

Spastic Quadriplegia(also: Spastic Tetraplegia)

The most severe subtype of spastic cerebral palsy, characterised by stiff, tight muscles (spasticity) and significantly reduced voluntary movement in all four limbs and often the trunk. People with spastic quadriplegia commonly use powered wheelchairs and may rely on switch…

Spinal Cord Injury(also: SCI)

Damage to the spinal cord that results in partial or complete loss of motor function, sensation, or both below the level of injury. The location of injury along the spine determines which abilities are affected: injuries at higher vertebrae (e.g., C4-C5) affect more of the body,…

Spinal Muscular Atrophy(also: SMA)

Spinal Muscular Atrophy (SMA) is an autosomal recessive neurodegenerative disease characterized by degeneration of spinal cord motor neurons, atrophy of skeletal muscles, and generalized weakness. Affecting approximately 1 in 6,000-10,000 live births, SMA is the leading genetic…

Switch Keyboard(also: Scanning Keyboard, On-Screen Scanning Keyboard)

A switch keyboard is a virtual keyboard interface designed for people with severe motor disabilities who cannot use a standard keyboard or pointing device. It works through a scanning mechanism: a cursor automatically moves across rows and columns of the keyboard, and the user…

Tetraparesis(also: Quadriparesis)

Partial weakness or reduced voluntary movement affecting all four limbs, commonly caused by cerebral palsy, spinal cord injury, or neuromuscular disease. Tetraparesis sits on a spectrum with tetraplegia (complete paralysis of all four limbs) and has significant implications for…

Upper Limb Motor Impairment(also: Upper Extremity Motor Disability, Hand and Arm Motor Impairment)

A condition affecting movement, strength, coordination, or fine motor control in the hands, wrists, arms, or shoulders that impacts a person's ability to use standard computer input devices. Causes include cerebral palsy, spinal cord injury, stroke, multiple sclerosis,…

Upper-Body Motor Impairment(also: Upper Extremity Impairment, Upper Limb Impairment)

Motor impairments affecting the upper extremities — including the arms, hands, fingers, shoulders, and neck — that limit a person's ability to perform tasks requiring fine motor control, gross motor movements, or upper-body strength. Common causes include spinal cord injury,…

Upper-Limb Amputation(also: Upper Limb Amputation, Arm Amputation)

The surgical or traumatic removal of all or part of an arm — including transhumeral (above elbow), transradial (below elbow), wrist disarticulation, and partial-hand levels. People with upper-limb amputation may use body-powered or myoelectric prostheses, or may choose no…

Upper-Limb Impairment(also: Upper Extremity Impairment, Arm Impairment, Hand Impairment)

A physical disability affecting the arms, hands, or fingers that limits a person's ability to perform fine motor tasks such as typing, using a mouse, or operating touchscreen devices. Upper-limb impairments can result from conditions including spinal cord injury, stroke,…