Glossary

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Personal-Scale Manufacturing(also: Desktop Manufacturing, Personal Fabrication)

The use of affordable, accessible manufacturing tools such as 3D printers, laser cutters, and CNC machines by individuals or small groups to produce custom physical objects, as opposed to relying on industrial-scale production. In the context of assistive technology,…

Personalized Object Recognition(also: Teachable Object Recognition)

A class of computer vision systems that allow an individual user — typically someone who is blind or has low vision — to train their device to recognize a small set of personally relevant objects (a specific coffee mug, a particular set of keys, a favourite notebook) by…

Personalized accessibility(also: Customizable accessibility, Adaptive accessibility)

An approach to accessibility that allows users to configure assistive features according to their individual needs, preferences, and abilities rather than providing a single fixed accommodation. Personalized accessibility recognizes that disabilities — particularly conditions…

Personally Identifiable Information(also: PII)

Any data that can be used to identify a specific individual, such as name, email address, location, biometric data, or device identifiers. For assistive technology users, PII concerns are heightened because the data collected often reveals sensitive information about a person's…

Pet Robot(also: Robotic Pet, Zoomorphic Robot, Companion Pet Robot)

A socially interactive robot designed to resemble and behave like an animal companion — most famously PARO (a baby harp seal) and AIBO (a robotic dog) — used to provide emotional comfort, reduce loneliness, stimulate engagement, and support therapy for older adults, particularly…

Phonemic Spelling(also: Phonetic Spelling)

The practice of spelling words based on their pronunciation rather than their conventional orthography, used as a workaround when text-to-speech systems do not support a desired language. In AAC contexts in Ghana, speech and language therapists experimented with typing English…

Photo Sharing(also: Photograph Sharing, Image Sharing)

The activity of showing, distributing, or discussing photographs with others — in person, via email, or through social-networking platforms. As a social practice it conveys memories, experiences, and identity; as an accessibility concern it presents barriers for blind and…

Photo-based Communication(also: Visual Communication Aid, Image-based Communication)

A communication strategy that uses photographs or images as the primary medium for conveying meaning, sharing experiences, and supporting conversation. For people with aphasia, intellectual disabilities, or other conditions that affect spoken and written language, photographs…

Phrase-Based Communication(also: Phrase-Based AAC, Pre-Stored Phrase Communication)

An augmentative and alternative communication approach where users select complete pre-composed phrases or sentences rather than constructing messages letter by letter or word by word. Phrase-based systems offer faster communication rates than spelling-based methods, which is…

Physical Crowdsourcing(also: Spatial Crowdsourcing, Physical World Crowdsourcing)

A form of crowdsourcing in which tasks require participants to perform actions in the physical world rather than completing digital tasks online. In an accessibility context, physical crowdsourcing has been applied to installing and maintaining navigation infrastructure such as…

Physical Rehabilitation(also: Physiotherapy, Physical Therapy)

A therapeutic process aimed at restoring, maintaining, or improving physical function, mobility, and strength through structured exercises and interventions. Physical rehabilitation is essential for people with motor disabilities, injuries, or neurological conditions to regain…

Physiological Computing(also: Biometric Computing, Biosignal-based Computing)

A computing paradigm that uses real-time physiological signals from the body to inform system responses and adaptations. Common signals include heart rate (via photoplethysmography), skin conductance (galvanic skin response), respiration, and brain activity (EEG). In…

Pico Projection(also: Pico Projector, Pocket Projector, Mini Projection)

A compact projection technology that enables small, portable devices to project images and information onto nearby surfaces. In accessibility contexts, pico projection offers an alternative to screen-based interfaces by allowing users to project communication props, maps,…

Pictograms(also: Pictogram, Picture Symbols, PCS)

Simplified pictorial symbols that represent concepts, objects, activities, emotions, or places, widely used as a form of augmentative and alternative communication (AAC) and as a visual support for autistic individuals, minimally verbal users, and people with cognitive…

Picture Communication Symbols(also: PCS, Boardmaker Symbols)

A widely used graphic symbol system for augmentative and alternative communication (AAC), consisting of simple, colorful line drawings representing words, phrases, and concepts. Developed by Mayer-Johnson (now part of Tobii Dynavox), PCS is one of the most common symbol sets…

Picture Exchange Communication System(also: PECS)

A structured augmentative and alternative communication (AAC) system that teaches individuals to use pictures to communicate with others. Developed by Andrew Bondy and Lori Frost in 1985, PECS uses a series of six phases to teach individuals — typically children with autism or…

Picture Prompting(also: Visual prompting, Pictorial instruction)

An instructional strategy that uses photographs or illustrations to depict how to complete each step of a task, providing visual guidance for people with developmental or intellectual disabilities. Picture prompts can be delivered through physical cards, printed instructions, or…

Picture Smart AI(also: JAWS Picture Smart AI)

Picture Smart AI is a feature of the JAWS screen reader (Freedom Scientific/Vispero) that uses multimodal AI models to describe images, charts, and on-screen content on demand. It can describe a photo, explain a chart, read text embedded in an image, or answer follow-up…

Piezo Vibrator(also: Piezoelectric Vibrator, Piezoelectric Actuator)

A device that converts electrical signals into mechanical vibrations using the piezoelectric effect, commonly used in tactile displays and haptic feedback systems for assistive technology. Piezo vibrators can be arranged in arrays to create tactile patterns that convey spatial…

Piezoelectric Actuator(also: Piezo Actuator, Piezoelectric Bimorph)

A device that converts electrical energy into precise mechanical motion using the piezoelectric effect — the property of certain materials to change shape when an electric voltage is applied. In assistive technology, piezoelectric actuators are the dominant mechanism used in…

Piggyback Prototyping(also: piggyback prototype, parasitic prototyping)

Piggyback prototyping is a research methodology in which researchers add new features or interventions to already-deployed, live systems rather than building standalone prototypes, enabling study of user behaviour with novel features in authentic real-world contexts. The…

Pin Array(also: Pin Matrix, Pin-Matrix Display)

A grid of individually controllable pins used in refreshable tactile displays to create tactile images and text. Each pin can be raised or lowered electronically, and in some displays raised to multiple heights, allowing the representation of graphical content through touch. Pin…

Pin Array Display(also: Pin Matrix Display, Tactile Pin Display)

A type of tactile display technology that uses an array of individually controllable pins that can be raised or lowered to create tactile patterns, textures, and graphics. Pin array displays are used in 2D tactile displays to present graphical information such as diagrams,…

Pin-Matrix Display(also: Tactile Pin Display, Pin Array Display, Two-Dimensional Braille Display)

A refreshable tactile display technology that uses a grid of individually controllable pins to create two-dimensional tactile images, as opposed to single-line refreshable Braille displays that show only one row of characters. Pin-matrix displays like the BrailleDis 7200 can…

Pitch Detection(also: Pitch Tracking, Fundamental Frequency Detection)

The computational process of determining the fundamental frequency (pitch) of an audio signal in real time. In accessibility, pitch detection is used in non-speech voice interfaces where changes in humming or vocal pitch are mapped to control commands — for example, a rising…

Plan Recognition(also: Intent Prediction, Action Prediction)

A technique in human-computer interaction where a system predicts the user's intended action based on patterns in their input behaviour and the current interaction context. By anticipating what the user is likely to do next, the system can weight recognition processes…

Pluggable User Interface(also: Pluggable UI, Alternative User Interface)

A pluggable user interface is an interchangeable interface component that can be swapped in or out of an application without changing the application's core functionality. In the Universal Remote Console (URC) framework, pluggable user interfaces connect to an abstract "user…

Pointing Device(also: Pointer Device, Input Device)

Any hardware device used to control the movement of a cursor or pointer on a computer screen, enabling users to select, click, drag, and interact with interface elements. Common pointing devices include the mouse, trackball, trackpad, touchscreen, stylus, joystick, head-tracking…

Pointing Device Gain(also: Control-Display Gain, Mouse Sensitivity, Pointer Speed)

The ratio between the movement of a physical input device (such as a mouse or trackball) and the resulting movement of the cursor on screen, typically measured in pixels per inch of device movement. Higher gain means the cursor moves further for a given physical movement. In…

Portable Reader(also: Portable Reading Device, Portable Reading Machine)

An assistive technology device that combines a camera or scanner with optical character recognition and text-to-speech output to enable blind or visually impaired users to read printed text independently in any location. Unlike traditional flatbed scanner-based reading systems…

Pose estimation(also: Body pose estimation, Human pose estimation)

The computational process of determining the position and orientation of a person's body joints and limbs from sensor data such as cameras, depth sensors, or inertial measurement units. In accessibility contexts, pose estimation enables applications like gesture-based…

Postural Support(also: Seating Support, Positioning Support)

Equipment and strategies that help maintain a person's body in a stable, functional position for activities including communication, eating, and using assistive technology. Adequate postural support is a prerequisite for many assistive technologies, particularly gaze-based…

Posture Detection(also: Posture Monitoring, Posture Recognition)

The use of sensors or computer vision to identify and monitor a person's body posture in real time. In assistive technology, posture detection systems can use accelerometers, gyroscopes, or cameras to determine whether a user is sitting, standing, slouching, or hunching, and…

Power Assist Device(also: Power assist wheel, Pushrim-activated power-assisted wheelchair, PAPAW)

A motorized attachment that adds electric propulsion assistance to a manual wheelchair without converting it into a full power wheelchair. Power assist devices typically attach to the wheelchair frame, wheels, or axle and amplify the user's pushing force, reducing physical…

Power Cards

Power Cards are a visual teaching strategy developed by Elisa Gagnon for autistic learners and others with social-communication differences. A Power Card is a small, portable card that pairs a brief scenario about a child's special interest (such as a favourite character) with a…

Power Wheelchair(also: Electric Wheelchair, Motorized Wheelchair, Power Chair)

A wheelchair propelled by an electric motor rather than manual pushing, essential for people with severe motor disabilities who lack the upper body strength or dexterity to operate a manual wheelchair. Power wheelchairs are typically controlled through joysticks, but alternative…

Power-Assist Add-On(also: Power Assist, Power-Assist Device, Wheelchair Power Assist)

A power-assist add-on is a retrofit device attached to a manual wheelchair that provides motorized propulsion while preserving the chair's manual structure, offering a middle ground between manual and full power wheelchairs. Commercial examples include the SmartDrive, Firefly,…

Powered Wheelchair(also: Electric Wheelchair, Motorized Wheelchair, Power Chair)

A wheelchair propelled by an electric motor and battery system rather than manual effort, typically controlled via a joystick or alternative input device. Powered wheelchairs are essential mobility aids for individuals who lack the upper body strength or coordination to operate…

Pre-Programmed Message(also: Stored Message, Canned Response, Pre-Set Phrase)

A message or phrase stored in an AAC device that can be quickly retrieved and spoken without requiring real-time composition. Pre-programmed messages trade expressiveness for speed—they enable faster communication but are limited to anticipated phrases. For backchanneling,…

Pre-compensation(also: Display Pre-compensation, Image Pre-compensation)

A technique in which images displayed on a computer screen are mathematically modified in advance to counteract the visual aberrations of the viewer's eye. Rather than relying on corrective lenses or magnification, pre-compensation transforms the source image so that when it…

Precompensation(also: Display Precompensation, Image Precompensation)

A technique in visual accessibility that pre-modifies displayed images in a way that is opposite to the optical distortion introduced by a user's eye, so that the image arriving at the retina more closely resembles the intended original. Precompensation works analogously to an…

Prediction Utilization(also: PU)

The percentage of opportunities where a user accepts a word prediction rather than continuing to type the word manually. Prediction utilization reflects user trust in a prediction system—higher quality predictions lead to higher utilization rates. Research shows that users…

Predictive Cursor(also: Anticipatory Cursor, Offset Cursor)

A cursor display technique designed to compensate for the delays inherent in speech-based or other high-latency input methods. A predictive cursor shows an indicator ahead of the actual cursor position, offset by the estimated distance the cursor will travel during the input…

Predictive Disambiguation(also: Dictionary-based Predictive Disambiguation, DBPD, Word Disambiguation)

Predictive disambiguation is the class of text-entry techniques in which each user input event is intentionally ambiguous (one keystroke covers several possible letters, one swipe covers many possible paths) and software resolves the ambiguity into a most-likely word using a…

Predictive Text(also: Text Prediction, Word Prediction, Autocomplete)

A software feature that suggests words or phrases as the user types, based on context, language models, and the user's typing history. Predictive text is a significant accessibility feature for people with motor impairments because it reduces the number of keystrokes needed,…

Preference Customization(also: User Preference Configuration, Personalization Settings)

The ability for users, particularly those using assistive technologies, to configure how they receive and interact with digital content based on their individual needs, preferences, and context. In accessibility, preference customization goes beyond basic assistive technology…

Press-and-Listen Paradigm(also: Sequential Navigation, Linear Content Consumption)

The fundamental interaction model of screen reader assistive technology, where users press keyboard shortcuts to move through web content elements one at a time and listen to each element being announced sequentially. This paradigm transforms the two-dimensional graphical…

Privacy Leak(also: Accidental Disclosure, Privacy Disclosure)

The unintentional capture and sharing of sensitive personal information through visual assistance technologies. Research has found that approximately 10% of images submitted to VAT services contain private content such as pregnancy tests, prescription medication, and people,…

Privacy Threat Model(also: Privacy Threat Analysis, Privacy Risk Assessment)

A systematic process for identifying, classifying, and evaluating potential privacy risks that a technology system may pose to its users. Privacy threat modeling extends security-focused frameworks (like Microsoft's STRIDE) to address privacy-specific concerns. The LINDDUN…

Proactive description(also: Proactive notification, Unsolicited description)

The ability of an assistive system to automatically provide relevant visual or environmental information without requiring the user to explicitly request it. For blind and visually impaired users navigating real-world environments, proactive description is critical — a human…