Title: What factors influence adaptation to post stroke homonymous hemianopia?
Funder: Health Education England

Abstract: Visual impairment is a common finding after stroke and it has been estimated that 60% of stroke survivors have some degree of visual impairment immediately after their stroke. Visual field loss is one commonly occurring visual impairment and can have negative implications on quality of life and activities of daily living causing loss of confidence, diminished enjoyment of reading and watching television, reduced mobility and increased risk of falls.Hemianopic visual field defects are associated with a reduced prognosis for successful rehabilitation, especially when combined with visual inattention. Treatment for visual field loss is inconsistent and not commonplace, even in stroke units where orthoptic services are provided. There are three main approaches to rehabilitation of visual impairment: adaptation/compensatory, substitution or restitution. A review by Pollock et al 2011 concluded that compensatory training was the most favourable treatment option. Compensatory/adaptation treatment methods are based on training the patient to adapt and compensate for their visual field loss.Adaptation to hemianopia occurs over time with and without therapy interventions. Some patients adapt quickly and others take much longer to adapt or struggle to adapt. There has been limited investigation into the mechanism of adaptation to visual field loss. Literature searches have identified a gap in knowledge for the adaptation process to hemianopia.This prospective observation case cohort study aims to explore the adaptation process to hemianopia in more detail. The profile of homonymous hemianopia will be closely monitored from the immediate acute through to the long-term stage post stroke to identify prognostic factors that predict adaptation to the visual status. All adult stroke patients admitted to Salford Royal Hospital following an acute stroke episode will be identified and screened for visual impairment. Results from this routine screening will be used to identify patients with a recent onset homonymous hemianopia (complete or partial). If the patient agrees to take consent to the study, written consent will be obtained for questionnaires for daily living and resilience, formal saccadic eye movement measurements using a saccadometer, as well as a timed obstacle course to assess navigation skills and obstacle avoidance.The study will comprise of two parts. Stroke survivors who do not wish to take part in the study with additional assessments will receive standard care as per the current practice at Salford Royal based on national guidelines. Stroke survivors who do consent to take part in the study will take part in the additional assessments in addition to standard assessment and treatment.All identified patients will be given a detailed information sheet explaining their ocular condition of homonymous hemianopia and will be offered paper based scanning exercises. These paper based scanning exercises are aimed at teaching a patient to adapt to their vision loss and were validated in the VISION trial (Visual Impairment in Stroke: Interventions or not). The scanning exercises will be simplified for patients with cognitive impairment.The primary outcome measure is the change in time and accuracy to complete an obstacle course; from the acute to long term post stroke stage; as a measure of adaptation to homonymous hemianopia. The impact of this study is that if we understand the process of adaptation to hemianopia and why some patients adapt better than others; we can target interventions and make better use of resources. This has a long term implication for patients suffering from this disabling condition and may impact on the length of a patients' rehabilitation journey and long term independence following post stroke visual impairment.

Lay abstract: Visual problems following a stroke are a common finding and can be in many forms including reduced / blurred vision, defective eye movements, loss of peripheral vision (visual field), reading difficulties and difficulties in the way we see objects (visual perception defects). One common finding across stroke units is the loss of peripheral vision to one side (homonymous hemianopia) which can have a huge impact on a person's treatment/rehabilitation and ability to return to a normal way of life. A loss of visual field is a partial or complete inability to see one side of the visual world and occurs in both eyes to the right or left side. From clinical experience, we find that some people adapt remarkably well to their visual field loss and within weeks of their stroke are able to read easily, negotiate new surroundings and appear to have little effect to their everyday activities, despite still having their visual field loss. Unfortunately, another group of people appear to be more affected by this loss of vision, struggling with everyday tasks such as reading, getting about and finding objects around them. Previous research has typically looked at just one aspect of patients with homonymous hemianopia, for example eye movements or reading ability or the effect of one particular treatment. No study has gathered information from a wide range of visual functions and the process of adaptation in close detail from the first days after stroke. This research aims to do just that with close monitoring of peoples adaptation and response to treatment from an early stage. The research plan is to identify people in the stroke unit who have a recent and new diagnosis of homonymous hemianopia. The brain scan information for these individuals will provide important information regarding the area of their brain affected. Information at this early stage will be gathered, such as the person's age, severity of stroke, cognition, general health and stroke-induced disabilities. These people will have a full assessment of vision taking account of functions such as central and peripheral vision, eye movements, visual perception and attention. This assessment will be carried out as early as possible after a stroke (typically within days of stroke onset), at the start of treatment and at regular intervals of follow up. All people will be offered treatment, as soon as they are able to engage with the training, with visual search exercises using a paper-based method with the intention of improving their scanning into the hemianopic field. Patient data will be divided into two categories, those who do adapt to their hemianopia and those who don't adapt. Adaptation to hemianopia will be measured using a persons' ability to complete an obstacle course, using the difference in time taken to complete the obstacle course from immediately after stroke to the long term assessment. An assessment of peoples' navigation abilities as a measure of their adaptation using an obstacle course, is included in this study as safe navigation is a skill which is valued by those who have suffered a stroke and is required for a safe discharge from hospital.Information from the visual assessment along with information about the person and their stroke will be examined to see how this relates and if it can be used to predict which patients will adapt well to their visual field loss and examine the reasons for this adaptation. The information that will be compared for the two groups includes details of the stroke, patient information such as ethnicity and gender, visual assessment information as well as a persons' level of resilience (measured using a resilience questionnaire) and quality of life (measured using various questionnaires). The intended outcomes of this project are to have a deeper understanding of the mechanisms of adaptation to hemianopia. If we understand the process better it will allow us to target treatments where and when they are needed and make better use of resources, as well as to target those people most in need of help. This in turn will have an impact on patient experiences. If we can pinpoint clinical features that predict adaptation, we can focus interventions on improving this clinical area from an earlier stage, hence having the potential to speed up the process of adaptation and improve a persons' quality of life from an earlier stage.

Research activity codes: 7.1 INDIVIDUAL CARE NEEDS
Health categories: STROKE