Understanding visual processing differences using short video tasks in adults with cerebral visual impairment

ISRCTN	ISRCTN65080173
DOI	https://doi.org/10.1186/ISRCTN65080173
Sponsor	University of St Andrews
Funder	University of St Andrews

Submission date: 19/05/2026
Registration date: 20/05/2026
Last edited: 20/05/2026

Recruitment status: Recruiting
Overall study status: Ongoing
Condition category: Nervous System Diseases

Prospectively registered

Protocol

Statistical analysis plan

Results

Individual participant data

Record updated in last year

Plain English summary of protocol

Background and study aims
Cerebral visual impairment (CVI) can affect how people process complex visual information, particularly in busy or moving environments. Some people experience difficulties seeing and integrating multiple visual elements at the same time, often referred to as dorsal stream dysfunction. This study aims to explore how adults with CVI respond to short naturalistic video tasks and compare these responses with adults with typical vision.

Who can participate?
Adults aged 18 years and over with an established diagnosis of cerebral visual impairment may participate. Adults with typical vision may also participate as part of the control group.

What does the study involve?
Participants first undergo a short eye screening assessment, including a structured question inventory used to identify features associated with dorsal stream dysfunction and determine their suitability for participation. Participants then view eight short videos showing everyday environments such as shops, beaches, and driving scenes. While watching the videos, participants describe aloud what they can see. After each video, participants complete a structured question inventory about their experience, including visual difficulty, stress, mental fatigue, and visual fatigue.

What are the possible benefits and risks of participating?
The study may improve understanding of cerebral visual impairment and support future development of assessment approaches and support strategies. Some participants with CVI may find certain visually busy videos tiring or stressful. Participants may pause, take breaks, skip videos, or stop participation at any time.

Where is the study run from?
University of St Andrews (UK)

When is the study starting and how long is it expected to run for?
January 2024 to December 2026

Who is funding the study?
University of St Andrews (UK)

Who is the main contact?
Helen St Clair Tracy, hsct1@st-andrews.ac.uk

Contact information

Helen St Clair Tracy
Principal investigator, Scientific, Public

University of St Andrews School of Medicine
North Haugh
St Andrews
KY16 9TF
United Kingdom

ORCID ID	0009-0009-3224-066X
Phone	+44 (0)7979481732
Email	hsct1@st-andrews.ac.uk

Study information

Primary study design	Observational
Observational study design	Case-control study
Scientific title	An observational pilot study comparing responses to short naturalistic video tasks in adults with cerebral visual impairment and control participants to investigate visual processing, stress, fatigue, and visual scene extraction
Study objectives
Ethics approval(s)	Approved 25/10/2023, School of Medicine Ethics Committee, University of St Andrews (University of St Andrews School of Medicine, North Haugh, St Andrews, KY16 9TF, United Kingdom; +44 (0)1334 463596; medethic@st-andrews.ac.uk), ref: MD17292
Health condition(s) or problem(s) studied	Cerebral visual impairment (CVI)
Intervention	Participants with cerebral visual impairment and control participants with typical vision will undergo ophthalmological screening assessment and structured question inventory assessment prior to participation. Participants will then view eight short naturalistic videos depicting everyday visual environments including shops, beaches, and driving scenes. Participants will describe aloud what they can see while viewing each video. Following each video, participants will complete structured questionnaire measures relating to visual difficulty, stress, mental fatigue, and visual fatigue. Quantitative and qualitative data including questionnaire responses, verbal descriptions, timing measures, and visual instance scoring will be analysed to compare visual processing profiles between adults with cerebral visual impairment and control participants.
Intervention type	Behavioural
Primary outcome measure(s)	Object identification performance measured using visual instance scoring and verbal scene description during naturalistic video tasks at a single study assessment Self reported visual difficulty measured using post-video Likert questionnaire responses during naturalistic video tasks at a single study assessment Task completion time measured using minutes during naturalistic video task assessment at a single study assessment
Key secondary outcome measure(s)
Completion date	31/12/2026

Eligibility

Participant type(s)
Age group	Mixed
Lower age limit	18 Years
Upper age limit	120 Years
Sex	All
Target sample size at registration	9
Key inclusion criteria	Adults with CVI group: 1. Established NHS diagnosis of cerebral visual impairment 2. Sufficient visual acuity to undertake the video tasks 3. Features consistent with dorsal stream dysfunction based on structured question inventory and ophthalmological assessment Control group: 1. Correctable typical visual acuity 2. No diagnosis of cerebral visual impairment 3. No evidence of features suggestive of cerebral visual impairment based on structured question inventory and ophthalmological assessment
Key exclusion criteria	1. Significant uncorrected visual impairment preventing participation in the video tasks 2. Inability to complete the structured video viewing and question procedures For control participants: 1. Any evidence suggestive of cerebral visual impairment or dorsal stream dysfunction based on ophthalmological assessment and structured question inventory
Date of first enrolment	16/01/2024
Date of final enrolment	31/12/2026

Locations

Countries of recruitment

United Kingdom
Scotland

Study participating centre

University of St Andrews

College Gate
North Street
St. Andrews
KY16 9AJ
Scotland

Results and Publications

Individual participant data (IPD) Intention to share	Yes
IPD sharing plan	The datasets generated and/or analysed during the current study will be published as supplementary information alongside the results publication. All shared data will be fully anonymised and will include participant transcripts, questionnaire responses, visual instance scoring data, and summary analyses. Audio recordings were deleted following transcription checking and anonymisation. No identifiable participant data will be shared.

Individual participant data (IPD) Intention to share

Yes

IPD sharing plan

The datasets generated and/or analysed during the current study will be published as supplementary information alongside the results publication. All shared data will be fully anonymised and will include participant transcripts, questionnaire responses, visual instance scoring data, and summary analyses. Audio recordings were deleted following transcription checking and anonymisation. No identifiable participant data will be shared.

Editorial Notes

20/05/2026: Study's existence confirmed by the School of Medicine Ethics Committee, University of St Andrews.