Clinical VR
glossary

360° video is video filmed in every direction at once, in which a viewer wearing a virtual reality headset can look around as if they were at the filming location.

3DoF (three degrees of freedom) is the ability of a virtual reality system to track only the rotation of the head, without following the movement of the body through space.

6DoF (six degrees of freedom) is the ability of a virtual reality system to track both the rotation of the head and the movement of the body forwards, sideways and up or down.

Active ageing is, according to the WHO, the process of optimising opportunities for health, participation and security in order to enhance quality of life as people age.

Acute pain is pain of recent onset and limited duration, usually associated with an identifiable injury, disease or procedure, which tends to resolve as healing occurs or the cause is treated.

Agitation is a state of excessive motor or verbal activity, associated with emotional tension, which may include restlessness, wandering, repeated shouting or aggression.

Alzheimer's disease is a progressive neurodegenerative disease and the most common cause of dementia, accounting for 60 to 70% of cases according to the WHO.

Anonymisation is the process of irreversibly transforming personal data so that the person they relate to can no longer be identified by any means reasonably likely to be used.

Anxiety is an emotion of apprehension or worry about an anticipated threat, accompanied by tension and physical signs; it becomes an anxiety disorder when it is excessive, persistent and interferes with daily life.

Artificial locomotion is any movement of the viewpoint in the virtual environment that does not match a real movement of the body, such as moving forwards with a controller or watching a video filmed while travelling.

Augmented reality (AR) is a technology that overlays digital images or information onto the view of the real world, without replacing it.

Autism spectrum disorder (ASD) is a neurodevelopmental condition characterised by persistent differences in social communication and interaction and by restricted, repetitive patterns of behaviour, interests or activities.

An avatar is the digital representation of a person in a virtual environment, which can reproduce their movements.

The base price is the maximum price a contracting authority is prepared to pay for performing all the services or supplies that make up the subject matter of a public contract.

Behavioural and psychological symptoms of dementia (BPSD) are disturbances of perception, thought, mood or behaviour that frequently occur in people with dementia.

Bias is a systematic error in the design, conduct, analysis or publication of a study that pushes its results away from the true effect in one direction.

Biofeedback is a technique that measures body signals, such as heart rate, breathing or muscle tension, and shows them to the person in real time so they can learn to regulate them.

Blinding is the practice, in a study, of keeping participants, clinicians or assessors unaware of who received the intervention and who received the comparison, so that their expectations do not influence the results.

CE marking is the mark by which the manufacturer indicates that the device meets the applicable requirements of European legislation, a condition for marketing it in the European Union.

Chronic pain is pain that persists or recurs for longer than three months, the criterion adopted in the WHO International Classification of Diseases (ICD-11).

Class I is the lowest-risk class of medical devices under Regulation (EU) 2017/745, in which the manufacturer can declare conformity without the involvement of a notified body.

Class IIa is the medium-low risk class of medical devices under Regulation (EU) 2017/745, whose conformity assessment requires the involvement of a notified body.

Classification of medical devices is the assignment of each device to a risk class (I, IIa, IIb or III), according to the rules in Annex VIII of Regulation (EU) 2017/745.

Clinical evaluation is the systematic and planned process of continuously generating, collecting, analysing and assessing the clinical data on a device, to verify its safety, performance and clinical benefit.

The CNPD (Comissão Nacional de Proteção de Dados) is the independent administrative authority that supervises and enforces compliance with the GDPR and national data protection law in Portugal.

Cognitive rehabilitation is an individualised intervention that seeks to improve, maintain or compensate for affected cognitive functions, such as attention, memory or executive functions, with goals linked to daily life.

Cognitive stimulation is a set of activities, usually in groups, that engage a person in thinking, memory, language and conversation tasks, with the aim of maintaining cognitive and social functioning.

A confidence interval is a range of values, calculated from a study's data, that indicates the precision of an estimate and the effect values compatible with those data, usually at 95%.

Continuing care is healthcare and social support provided to people in a situation of dependency, after the acute phase of illness, to promote recovery, rehabilitation, independence or maintenance of health.

A contracting authority is a body that must follow the Public Contracts Code when it enters into contracts, such as the State, local authorities, public institutes and bodies governed by public law.

A contraindication is a situation or condition of the person in which a device, medicine or intervention should not be used, because the risk may outweigh the benefit.

The control group is the set of participants in a study who do not receive the intervention being tested, serving as a comparison to estimate the effect of that intervention.

The controller is the person or body that, alone or jointly with others, determines the purposes and means of the processing of personal data (GDPR, Article 4(7)).

A cooperation agreement is an agreement between the Social Security Institute and an IPSS or equivalent body under which the State co-funds the running of a social service, such as a residential care home or a day centre.

Mecenato is the giving of donations, in cash or in kind, to public or non-profit bodies without economic return, which entitles the donor to tax benefits under the Portuguese Tax Benefits Statute.

A crossover trial is a trial in which each participant receives both the intervention and the comparison, in successive periods and in a randomly allocated order, acting as their own control.

Cybersickness is the set of symptoms, such as nausea, dizziness, disorientation and eye strain, that some people experience during or after using virtual reality.

Data concerning health are personal data related to a person's physical or mental health, including the provision of care, that reveal information about their health status (GDPR, Article 4(15)).

Data minimisation is the GDPR principle under which personal data must be adequate, relevant and limited to what is necessary for the purposes of the processing (Article 5(1)(c)).

A day centre is the Portuguese social care service that provides, during the day, a range of services to older people who still live at home, helping them remain in their social and family environment.

A day hospital is a form of hospital care in which the person receives treatment, procedures or follow-up during the day and returns home the same day, without staying overnight.

Delirium is an acute, fluctuating disturbance of attention and awareness, with impaired cognition, caused by a medical condition, medication or withdrawal, and usually potentially reversible.

Dementia is a syndrome, usually chronic and progressive, in which decline in memory, thinking or other cognitive functions is enough to interfere with independence in daily activities.

Depression is a mental disorder characterised by depressed mood or loss of interest and pleasure in activities, for most of the day, nearly every day, for at least two weeks.

Direct award (ajuste direto) is the Public Contracts Code procedure in which the contracting authority directly invites one entity of its choice to submit a tender.

Distraction, in the context of pain and anxiety, is the technique of shifting a person's attention away from an unpleasant stimulus, such as a painful procedure, towards a more engaging one.

A DOI is a unique, permanent digital identifier assigned to a scientific article, book or dataset, providing a stable link to it even if its web address changes.

A DPIA is an assessment, provided for in Article 35 of the GDPR, that the controller must carry out before any data processing likely to result in a high risk to people's rights and freedoms.

The DPO is the person an organisation designates to advise it on the GDPR, monitor compliance and act as the contact point for data subjects and the supervisory authority (GDPR, Articles 37 to 39).

Effect size is a measure of the magnitude of a difference or association found in a study, indicating how large the effect is, not just whether it is statistically significant.

An ERPI (estrutura residencial para pessoas idosas, residential structure for older people) is the Portuguese social care service offering collective accommodation, temporary or permanent, to older people, with social support and care.

The EU declaration of conformity is the document in which the manufacturer states, under its own responsibility, that the device meets the requirements of Regulation (EU) 2017/745.

EUDAMED is the European database on medical devices, laid down in Article 33 of Regulation (EU) 2017/745, which brings together information on economic operators, devices, certificates, vigilance and market surveillance.

Exposure therapy is a cognitive behavioural therapy technique in which a person faces, gradually and safely, situations or stimuli they fear, in order to reduce fear and avoidance.

Extended reality (XR) is the umbrella term covering virtual reality, augmented reality and mixed reality.

Eye tracking is the ability of some virtual reality headsets to detect where the person is looking, using sensors facing the eyes.

A feasibility study is a study that assesses whether an intervention or a future study can be carried out in a given setting: whether participants take part, whether staff can deliver it and whether it is tolerated.

Field of view (FOV) is the angular extent of the image that a virtual reality headset shows at once, measured in degrees.

Frailty is a geriatric syndrome of increased vulnerability, resulting from reduced physiological reserves, which makes a person more susceptible to falls, hospitalisation, dependency and death when faced with minor stressors.

Fresnel lenses are thin, lightweight lenses made of concentric rings, which for years were the most common optics in virtual reality headsets.

Gamification is the use of elements typical of games, such as points, levels, challenges or rewards, in activities that are not games, to increase motivation.

The GDPR is Regulation (EU) 2016/679, which lays down the rules protecting natural persons in the processing of their personal data throughout the European Union, applicable since 25 May 2018.

GRADE is an international system for rating the certainty of evidence on four levels (high, moderate, low and very low) and the strength of clinical recommendations.

Hand tracking is the ability of a virtual reality headset to detect, using cameras, the position and gestures of the hands, without controllers.

The home support service (SAD, serviço de apoio domiciliário) is the Portuguese social care service that provides care and services at home to people or families in a situation of dependency who cannot, temporarily or permanently, meet their basic needs or carry out daily activities.

Immersion is the extent to which a virtual reality system replaces stimuli from the real world with those of the virtual environment, as described by its technical characteristics.

An individual care plan is the document in which the team records, for each service user, the assessed needs, goals, interventions to be carried out, who is responsible and review dates.

Infarmed (National Authority of Medicines and Health Products, I. P.) is the Portuguese competent authority for medicines and health products, including medical devices.

An informal carer is a person, usually a family member or someone close, who regularly cares for someone in a situation of dependency without being paid for that care.

Informed consent is the free and informed permission a person gives for a health intervention or for taking part in a study, after receiving adequate information about its purpose, nature, benefits and risks.

Inpatient admission is the admission of a person to a healthcare unit to receive care that requires them to stay, including at least one night, under the team's supervision.

Instructions for use are the information provided by the manufacturer to inform the user of the device's intended purpose and proper use, and of any precautions to be taken.

Intended purpose is the use for which the manufacturer intends the device, as stated on the label, in the instructions for use and in promotional or sales materials.

Interpupillary distance (IPD) is the distance between the centres of the pupils of the two eyes, which a virtual reality headset must match for the image to be sharp and comfortable.

An IPSS (instituição particular de solidariedade social) is a non-profit legal entity, set up by private initiative and not run by the State, that gives organised expression to the duty of solidarity, helping to give effect to social rights.

ISO 13485 is the international standard that sets out the requirements of a quality management system for organisations that design, produce or supply medical devices, for regulatory purposes.

Kiosk mode is a configuration that locks a device into a single application, preventing access to menus, stores or other functions.

Latency, in virtual reality, is the delay between a head movement and the corresponding update of the image in the headset.

The level of evidence is a rating of how much confidence can be placed in a scientific finding, according to the type and quality of the studies behind it.

A life story is a record, made with the person and their family, of the path, relationships, places, occupations, likes and significant events of someone's life, used to personalise care.

Loneliness is the subjective, unpleasant experience of feeling that one's social relationships are insufficient, in number or quality, compared with those one would wish for.

A manufacturer, under Regulation (EU) 2017/745, is the natural or legal person who manufactures or fully refurbishes a device, or has a device designed or manufactured, and markets it under its own name or trademark.

The MDR is Regulation (EU) 2017/745, which sets the rules for placing on the market and using medical devices in the European Union, applicable since 26 May 2021.

A medical device is any instrument, apparatus, equipment, software or other article that the manufacturer intends for medical purposes, such as diagnosis, prevention, monitoring, treatment or alleviation of disease.

A meta-analysis is a statistical method that combines the results of several studies on the same question to produce an overall estimate of the effect, more precise than that of any single study.

Mild cognitive impairment is a decline in memory or other cognitive functions greater than expected for age, but which does not significantly compromise independence in daily activities.

Mindfulness is the practice of paying attention, intentionally and without judgement, to what is happening in the present moment: breathing, bodily sensations, thoughts and emotions.

The minimal clinically important difference is the smallest change in an outcome measure that patients or service users perceive as beneficial and that would, on its own, justify a change in care.

A Misericórdia (Santa Casa da Misericórdia, Holy House of Mercy) is a non-profit brotherhood of Catholic origin, dedicated to social action and health, present in almost every Portuguese municipality.

Mixed reality (MR) is the combination of digital elements with the real environment, in which virtual objects are anchored to physical space and can react to it.

Motor rehabilitation is the set of interventions that seek to recover, maintain or compensate for strength, range of motion, coordination, balance and gait after illness, injury or loss of function.

Multisensory stimulation is an approach that offers controlled stimuli to several senses (sight, hearing, touch, smell) to promote comfort, attention, relaxation or interaction.

A non-pharmacological intervention is any healthcare approach that does not use medicines, such as exercise, psychological therapies, cognitive stimulation, music or distraction, used on its own or alongside drug treatment.

A notified body is an independent organisation, designated by a Member State, that assesses the conformity of medical devices with Regulation (EU) 2017/745 before they are placed on the market.

The numeric pain rating scale is a tool in which a person rates the intensity of their pain with a number from 0 («no pain») to 10 («worst pain imaginable»).

Occupational therapy is the health profession that helps people take part in the daily activities that matter to them, such as self-care or leisure, by adapting the activity or the environment.

An open tender (concurso público) is the Public Contracts Code procedure in which any interested party that meets the requirements may submit a tender, after a contract notice is published.

The p-value is the probability of obtaining results at least as extreme as those observed if there were in fact no effect or difference (the null hypothesis).

Palliative care is active, holistic care that seeks to improve the quality of life of people with serious, incurable or advanced illness and of their families, by preventing and relieving physical, psychological, social and spiritual suffering.

Pancake lenses are a type of optics for virtual reality headsets that folds the light path between polarised layers, allowing thinner lenses placed closer to the display.

Parkinson's disease is a progressive neurodegenerative disease, characterised mainly by slowness of movement, resting tremor and rigidity, frequently accompanied by non-motor symptoms.

Passthrough is the feature of a virtual reality headset that shows, through its external cameras, a real-time image of the space around the wearer.

Peer review is the process in which a scientific work is assessed by independent experts in the same field before it is published in a scientific journal.

Per-eye resolution is the number of pixels a virtual reality headset shows to each eye, which, together with the optics and field of view, determines how sharp the image is.

Person-centred care is a way of providing care that starts from each person's history, values, preferences and abilities, rather than only from the disease or the tasks to be done.

A phobia is an intense, persistent fear out of proportion to a specific object or situation, such as heights, flying, animals or needles, which usually leads to avoidance.

Photosensitive epilepsy is a form of epilepsy in which seizures can be triggered by visual stimuli, such as flashing lights or certain high-contrast patterns.

Photosensitivity, in the context of virtual reality and screens, is susceptibility to adverse reactions, including epileptic seizures, triggered by flashing lights or visual patterns.

Physiotherapy is the health profession that assesses and intervenes in the body's movement and function, mainly through therapeutic exercise, manual techniques and education, to prevent, recover or maintain functional capacity.

A pilot study is a small-scale version of a larger study, carried out to test whether the planned procedures work in practice, not to show whether the intervention is effective.

Portugal 2030 is the partnership agreement between Portugal and the European Commission that organises the use of EU cohesion policy funds in the 2021-2027 programming period.

Post-market surveillance is the set of activities through which the manufacturer systematically and proactively collects and reviews experience gained with devices already on the market, to identify any need for corrective action.

Post-traumatic stress disorder (PTSD) is a disorder that may develop after exposure to a traumatic event, with intrusive memories, avoidance, negative changes in mood and heightened arousal.

A pre-post study is a study in which an outcome is measured in the same people before and after an intervention, without a control group, and the difference is compared.

Preoperative anxiety is the state of apprehension, fear or tension a person feels before surgery or anaesthesia, common in both adults and children.

Presence is the subjective feeling of being there, in the virtual environment, even though the person knows they are physically somewhere else.

Prior consultation (consulta prévia) is the Public Contracts Code procedure in which the contracting authority directly invites at least three entities of its choice to submit tenders.

PRISMA is an international guideline setting out what a systematic review or meta-analysis should report, including a checklist and a flow diagram of study selection.

Procedural pain is pain caused by medical or nursing procedures, such as venepuncture, vaccinations, dressing changes, repositioning or examinations.

The processor is the person or body that processes personal data on behalf of the controller, following its instructions (GDPR, Article 4(8)).

The PRR is Portugal's plan of reforms and investments funded by the European Union's Recovery and Resilience Facility, created after the COVID-19 pandemic; its implementation ended on 31 August 2026.

Pseudonymisation is the processing of personal data in such a way that they can no longer be attributed to a specific person without the use of additional information, kept separately and protected (GDPR, Article 4(5)).

The Public Contracts Code is the Portuguese law, approved by Decree-Law 18/2008, that governs how public and equivalent bodies choose suppliers and enter into and perform contracts.

PubMed is a free search engine for biomedical literature, maintained by the United States National Library of Medicine, that mainly provides access to the MEDLINE database.

Quality of life is, according to the WHO, a person's perception of their position in life, in the context of the culture and value systems in which they live, and in relation to their goals, expectations, standards and concerns.

A randomised controlled trial is a study in which participants are allocated by chance to the intervention being studied or to a control group, so that outcomes can be compared without the choice influencing who receives what.

Refresh rate is the number of times per second that the displays of a virtual reality headset show a new image, measured in hertz (Hz).

Relaxation, in a clinical context, is the set of techniques aimed at lowering physical and mental arousal, such as slow breathing, progressive muscle relaxation or guided imagery.

Reminiscence therapy is a psychosocial intervention that uses prompts such as photographs, music, objects or places to help a person recall and share memories and experiences from their life.

Risk management is the continuous process of identifying the hazards of a medical device, estimating and evaluating the risks, controlling them and monitoring the effectiveness of those controls, according to the ISO 14971 standard.

The RNCCI (Rede Nacional de Cuidados Continuados Integrados) is the Portuguese public network, created in 2006, that provides healthcare and social support to people in a situation of dependency, for recovery, rehabilitation or maintenance.

A scoping review is a systematic literature review that maps what has already been studied on a topic, what kinds of evidence exist and where the gaps are, without aiming to answer whether an intervention works.

Sensory conflict is the mismatch between information from the eyes and from the vestibular (balance) system, the most widely cited explanation for motion sickness and cybersickness.

A serious incident is any incident involving a medical device that directly or indirectly led, might have led or might lead to death, a serious deterioration in a person's state of health or a serious public health threat.

A Snoezelen room is a space for controlled multisensory stimulation, with light, sound, textures and scents, created in the Netherlands in the 1970s for people with intellectual disabilities.

The SNS (Serviço Nacional de Saúde, National Health Service) is the set of public institutions and services through which the Portuguese State guarantees the right to health protection, universally and comprehensively.

Social innovation is the development of new, or significantly improved, responses to social problems that create value for the community and are more effective than existing solutions.

Social isolation is the objective situation of having few social contacts and relationships, or infrequent contact, with family, friends or the community.

Sociocultural animation is the set of cultural, recreational, social and educational activities organised to promote people's participation, social contact and independence, particularly in care settings for older people.

Software as a medical device is software that, on its own, has a medical purpose assigned by the manufacturer and is therefore regulated as a medical device.

Spatial audio is sound processed to appear to come from a specific direction and distance in the virtual environment, keeping that position when the person turns their head.

SRN (single registration number) is the number assigned by the competent authority to each manufacturer, authorised representative or importer when it registers in EUDAMED.

A standalone headset is a virtual reality headset with its own processor, battery and storage, which works without a cable or an external computer.

The standardised mean difference is the difference between the means of two groups divided by the standard deviation, which allows studies that measured the same outcome on different scales to be compared and combined.

Stereoscopic video is video with a slightly different image for each eye, which creates the perception of depth.

A stroke (cerebrovascular accident) is sudden damage to the brain caused by interruption of blood flow (ischaemic stroke) or by rupture of a blood vessel (haemorrhagic stroke).

Systematic desensitisation is a behavioural technique, described by Joseph Wolpe, that combines relaxation with gradual exposure to a hierarchy of feared situations, from least to most difficult.

A systematic review is a research synthesis that searches for, selects and appraises all relevant studies on a defined question, using an explicit, reproducible method set out before it begins.

Technical documentation is the set of documents the manufacturer must draw up and maintain to demonstrate that the device complies with Regulation (EU) 2017/745.

Technical specifications are the characteristics required of the goods or services to be contracted, set out in the tender specification in a way that guarantees equal access for bidders and competition.

The caderno de encargos (tender specification) is the public procurement document that sets out, in numbered articles, the clauses to be included in the contract to be signed.

Total pain is the concept, proposed by Cicely Saunders, that the suffering of a person with advanced illness has physical, psychological, social and spiritual dimensions that influence one another.

UDI (unique device identification) is a numeric or alphanumeric code, created according to international standards, that allows a medical device on the market to be identified unambiguously.

A ULS (unidade local de saúde, local health unit) is the SNS body that brings hospitals and primary care (health centres) in a geographical area under a single management.

Vertigo is the illusory sensation of movement, usually rotation, of oneself or the surroundings, frequently caused by disorders of the vestibular system of the inner ear or its connections to the brain.

A virtual environment is the space presented to the person in virtual reality, whether computer-generated or filmed in 360° video.

Virtual reality (VR) is a technology that replaces what a person sees and hears with a generated or filmed environment, shown in a dedicated headset that follows the movements of the head.

A virtual reality headset is a head-worn device, with screens and lenses in front of the eyes and motion sensors, that presents a virtual environment to the wearer.

The visual analogue scale is a self-report tool in which a person marks, on a line usually 10 cm long between «no pain» and «worst pain imaginable», the intensity of what they feel.

Well-being is the state in which a person feels well, physically, mentally and socially, and evaluates their life positively, including pleasant emotions, satisfaction and meaning.

A wellness product is a product, device or app intended for leisure, relaxation or lifestyle, with no stated medical purpose, and which is therefore not regulated as a medical device.