Visual Perception Difficulties After Stroke

Study Overview
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Brief Summary
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The goal of this observational study is to learn how well the Oxford Visual Perception Screening (OxVPS) tool can identify stroke survivors with visual perception difficulties. The main aim is to determine the accuracy and utility of the OxVPS compared to the current gold standard assessment in stroke survivors. In other words, how well can the Oxford Visual Perception Screening tool (OxVPS) identify stroke patients with visual perception problems? Participants will completed the OxVPS and the current gold standards visual perception screening tool.

Detailed Description
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This is a non-experimental cross-sectional study. It aims to compare the new screening test OxVPS to the gold standard tests for visual perception difficulties. Patients will be recruited at stroke rehabilitation units at hospitals in the North East of England and in Oxfordshire. Following consent: Participants will complete the paper version of the Oxford Visual Perception Screen OxVPS ( 15 min). Participants will complete screening for visual perception problems with a validated screening tool ( 30-120 min). Participants will complete screening for cognition alterations and sensory vision with validated screening tools. ( 30 min) Stroke details (time since stroke, severity) and demographic data (age, socio-economic status) will be collected to evaluated representativeness of the sample.

Official Title
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Accuracy and Utility of the Oxford Visual Perception Screening (OxVPS), a Screening for Visual Perception Difficulties in Stroke Survivors

Conditions
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Stroke, Visual Perception

Intervention / Treatment
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* Diagnostic Test: OxVPS


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients with a clinical diagnosis of stroke (ischemic stroke and/or intracerebral haemorrhage). Within 6 weeks of confirmed stroke. Exclusion Criteria: Insufficient understanding of English Clinical concerns that patient is unable follow simple instructions. Clinical concerns that patient is unable to concentrate for 15 minutes. No capacity to provide informed consent.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Stroke survivors<br>Individuals who have survived a stroke | Diagnostic Test: OxVPS<br>* Comparing a new screening tool, the Oxford visual perception screening, to the gold standard, Rivermead Perceptual Battery Assessment.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Validity of OxVPS | Convergent and discriminate validity will be assessed. Convergent validity expressed as a correlation between total score on OxVPS and RPAB. Discriminate validity to be expressed as correlation between OxVPS score and scores of cognitive and sensory vision assessments. Both calculated by a non-parametric Spearman correlation and estimate a 95% confidence interval. The analysis can be completed through the cor.test function in the base package of R. | All testing completed in 2 weeks | 
| Reliability of OxVPS | The inter-rater reliability of OxVPS will be evaluated through a Bland-Altman analysis [26]: we will calculate the difference in OxVPS scores between raters for each patient. Subsequently, we will plot the difference in scores as a function on the average score to evaluate a bias between the raters (mean difference) that might vary based on severity of a patient's visual perceptual problems. We will report the mean difference, standard deviation, and limits of agreement within where 95% of differences between raters fall. A t-test will indicate if the mean difference is significantly different from 0. Analyses will be performed in R with the functions from blandr package (e.g. blandr.statistics and blandr.draw) or functions from a similar package. | 2 weeks |