Glossary

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Psychometric validation(also: Psychometric evaluation, Instrument validation)

The process of establishing that a measurement instrument (such as a questionnaire or scale) possesses adequate reliability (consistency of measurement), criterion validity (correlation with established measures), and construct validity (measuring the intended theoretical…

Psychomotor testing(also: Psychomotor assessment, Motor performance testing)

The measurement of cognitive-motor integration — how quickly and accurately a person can translate mental intentions into physical actions such as reaching, pointing, grasping, or tapping. Psychomotor tests assess reaction time, movement speed, accuracy, coordination, and…

Psychophysics

Psychophysics is the scientific study of the quantitative relationship between physical stimuli and the sensations and perceptions they produce. Founded in the 19th century, it uses rigorous experimental methods to measure how humans detect, discriminate, and scale sensory…

Psychosocial Disability(also: Psychosocial Impairment)

A disability that stems from diverse mental, cognitive, or emotional experiences that lead to impairment and experienced barriers in social participation. Psychosocial disabilities include conditions such as ADHD, anxiety, depression, bipolar disorder, and other mental health…

Psychosocial Impact of Assistive Devices Scale(also: PIADS)

A 26-item self-report questionnaire designed to measure the psychosocial impact of an assistive technology device on a person's functional independence, well-being, and quality of life. PIADS assesses three subscales: competence (subjective feelings of competence, productivity,…

Public Access System(also: Kiosk, Self-Service Terminal, Public Information Kiosk)

Interactive computer terminals placed in public locations for use by the general population, including ticket vending machines, ATMs, check-in kiosks, and information displays. These systems present unique accessibility challenges because users cannot customize them, may have…

Public Access Terminal(also: Public Kiosk, Public Information Terminal)

A Public Access Terminal is an interactive computing device installed in public spaces for use by the general population, including information kiosks, ticketing machines, check-in terminals, voting machines, and ATMs. Accessibility of public access terminals is particularly…

Public Digital Terminal(also: PDT, Self-Service Terminal, Self-Service Kiosk)

A publicly available interactive electronic device that provides services or information to users, such as ATMs, ticket vending machines, check-in kiosks, and information points. Public digital terminals present significant accessibility challenges because users cannot install…

Public Transport Accessibility(also: Transit Accessibility, Accessible Public Transportation)

The design of buses, trains, stations, stops, timetables, and associated services to be usable by people with all types of disabilities. This includes physical features (ramps, lifts, tactile paving, audio announcements), information accessibility (large print, screen reader…

Pull Notification(also: On-Demand Notification, User-Initiated Notification)

A notification or information delivery model where content is provided only when explicitly requested by the user, in contrast to push notifications which are delivered automatically. In assistive navigation contexts, pull notifications allow blind users to request specific…

Pulmonary Rehabilitation(also: PR, Respiratory Rehabilitation)

A supervised, multidisciplinary program for people with chronic respiratory diseases that combines patient education, exercise training, and self-management skills to reduce symptoms, improve quality of life, and increase physical activity. During pulmonary rehabilitation,…

Pulse Oximetry(also: Pulse Oximeter, SpO2 Monitoring)

A non-invasive method of monitoring blood oxygen saturation (O2sat) and heart rate using a sensor typically placed on the finger or wrist. Pulse oximeters use light absorption through the skin to estimate the percentage of hemoglobin in the blood that is carrying oxygen. In…

Pupil Diameter(also: Pupil Size, Aperture Size)

The width of the opening in the iris through which light enters the eye, typically ranging from about 2mm in bright light to 8mm in darkness. Pupil diameter significantly affects visual quality because it determines how much of the eye's optical aberrations influence the image…

Pupillometry(also: Pupil Dilation Measurement)

A psychophysiological measurement technique that tracks changes in pupil diameter as an objective indicator of cognitive workload, mental effort, and emotional arousal. In accessibility research, pupillometry provides a non-invasive way to assess how demanding an interface or…

Purposive Sampling(also: Purposeful Sampling, Judgment Sampling)

A non-probability sampling method in which researchers deliberately select participants based on specific characteristics relevant to the research questions. In accessibility research, purposive sampling is commonly used to recruit participants with particular disabilities,…

Pursed-lip Breathing(also: PLB)

A breathing technique in which the person inhales gently through the nose and exhales slowly through lightly pursed lips, with the exhalation lasting at least twice as long as the inhalation. The prolonged exhalation against pursed lips creates positive back-pressure in the…

Push-to-Talk(also: PTT, Push to talk)

An interaction pattern where a user presses and holds (or taps) a dedicated button to signal the start of an input — historically used in two-way radios, now common in voice assistants and conversational interfaces as an alternative to continuous listening. In accessibility…

Pusher Syndrome(also: Contraversive Pushing, Lateropulsion)

A clinical disorder occurring in some stroke survivors in which the patient actively pushes their body weight away from the non-paralyzed (non-hemiparetic) side, leading to a severe loss of postural balance. Typically caused by damage to the left or right brain, pusher syndrome…

Put That There(also: Put-That-There)

A pioneering multimodal interactive system built at MIT's Architecture Machine Group (1979-1980), reported by Bolt (1980) and further developed by Schmandt and Hulteen (1982). Users seated in a 'media room' could manipulate a graphical database — such as a Caribbean shipping map…