Rehabilitating Visual Deficits Caused by Stroke
- Conditions
- QuadrantanopiaStroke Induced Vision LossHemianopiaHemianopsia
- Interventions
- Behavioral: Training in the blind field
- Registration Number
- NCT04878861
- Lead Sponsor
- University of Oxford
- Brief Summary
This research aims to understand the efficacy of a visual training task to improve visual loss after stroke, also known as hemianopia. The investigators aim to understand whether training can improve vision and which areas or pathways in the brain are responsible for this improvement.
- Detailed Description
Damage to the primary visual cortex (V1) due to stroke usually results in loss of visual function in half of the visual world, this is known as hemianopia. This visual loss can negatively affect quality of life, as most stroke survivors are no longer permitted to drive and have difficulties with navigation and socialising. There are currently limited treatment options, although recent evidence suggests that visual training can be effective in improving visual function (Huxlin et al, 2009; Cavanaugh \& Huxlin, 2017). The aim of this research is to determine the capacity for visual rehabilitation after stroke using visual training and to understand the underlying brain mechanisms that might drive these improvements. This study will help the investigators to understand the brain mechanisms involved in visual rehabilitation and may allow the investigators to predict those most likely to benefit from visual rehabilitation in the future.
Twenty stroke survivors with hemi- or quadrantanopia will complete a 6-month visual motion discrimination training programme at home. Each participant will have three study visits; at baseline, 6-months and 9-months. At each visit the investigators will take measures of 1) visual fields 2) detailed tests of visual function 3) quality of life and 4) MRI scans of brain structure, function and neurochemistry. Between the baseline (0 month) and 6-month post-training session, participants will complete visual training at home. Between the 6-month post-training session and 9-month follow up, participants will not complete visual training at home. This study will therefore allow the investigators to determine whether rehabilitation improves conscious visual perception and quality of life as well as providing understanding of the neural mechanisms that underlie this improvement. The investigators will also determine whether improvements or neural changes persist after 3-months without training.
Recruitment & Eligibility
- Status
- RECRUITING
- Sex
- All
- Target Recruitment
- 20
- Aged 18-80
- Participant is willing and able to give informed consent for participation in the study
- Fluent English-speaking healthy adults
- Has suffered damage to the visual cortex at least 6 months before the study
- Previous eye disease or impairment other than hemianopia
- Neurological or psychiatric illness
- Contraindication to MRI
- Pregnant or breast feeding
- Second stroke during training
Data quality assurance (participant data will be removed from analysis for the following reasons):
- Concurrent participation in other "vision therapy"
- Unreliable visual fields, indicated by greater than 20% fixation losses, false positives, or false negatives
- Inability to demonstrate fixation stability on eye movement monitored testing
- Failure to complete at least 100 training sessions over 6-months
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- SINGLE_GROUP
- Arm && Interventions
Group Intervention Description Training in blind field Training in the blind field All participants undergo this intervention. Internal control is comparing sighted and non-sighted parts of the field.
- Primary Outcome Measures
Name Time Method Change in motion discrimination thresholds after 6 months of training 6 months Change in normalised discrimination thresholds on psychophysical motion discrimination task at two trained locations between baseline (0-month) and 6-month follow up. These assessments will be based on what motion can be reliably detected at a 75% correct level of performance.
- Secondary Outcome Measures
Name Time Method Maintenance of improvement in motion discrimination thresholds at 9-month follow up. 9 months No change in normalised discrimination thresholds on psychophysical motion discrimination task at two trained locations between 6-month and 9-month follow up. These assessments will be based on what motion can be reliably detected at a 75% correct level of performance.
Change in visual quality of life 6 months Change on the Visual Function Questionnaire 25 between baseline (0-month) and 6-month follow up.
Maintenance of visual quality of life 9 months No change in visual quality of life as measured by the Visual Function Questionnaire 25 between 6-month and 9-month follow up.
Maintenance contrast detection at trained locations 9 months No change in detection of stimulus at 1%, 5%, 10%, 50% and 100% contrast between the 6-month and 9-month follow up.
Maintenance of white matter integrity 9 months No change of integrity in LGN-hMT+ and LGN-V1 tracts between 6-month and 9-month follow up, assessed by diffusion-weighted imaging.
Change in neurochemistry 6 months Change in neurochemistry in visual motion area, hMT+ between baseline (0-month) and 6-month follow up, assessed by Magnetic Resonance Spectroscopy (MRS).
Change in area improved on the Humphrey perimetry (24-2 and 10-2) 6 months Change in area improved on a composite measure of deficit size calculated from 24-2 and 10-2 across both eyes. Area of improvement will be calculated as the area where the sensitivity improved by more than 6 decibels (dB) relative to pre-training.
Maintenance area improved on the Humphrey perimetry (24-2 and 10-2) 9 months No change in area improved on a composite measure of deficit size calculated from 24-2 and 10-2 across both eyes. Area of improvement will be calculated as the area where the sensitivity improved by more than 6dB relative to pre-training.
Change in white matter integrity 6 months Change in white matter integrity in lateral geniculate nucleus (LGN) to extrastriate motion area (hMT+) and LGN to primary visual cortex (V1) tracts between baseline (0-month) and 6-month follow up, assessed by diffusion-weighted imaging
Change in brain activity during visual stimulation (Blood-oxygen-level-dependent imaging, or BOLD, signal change) 6 months Change in brain activity during moving visual stimulation, assessed by functional magnetic resonance imaging (BOLD signal) in visual motion area, hMT+ between baseline (0 month) and 6-month follow up.
Change in contrast detection at trained locations 6 months Change in detection of stimulus at 1%, 5%, 10%, 50% and 100% contrast baseline (0-month) and 6-month follow up.
Maintenance of neurochemistry 9 months No change in neurochemistry in visual motion area, hMT+ between 6-month and 9-month follow up, assessed by Magnetic Resonance Spectroscopy (MRS).
Maintenance of brain activity during visual stimulation (BOLD signal change) 9 months Maintenance of brain activity during moving visual stimulation, assessed by functional magnetic resonance imaging (BOLD signal) in visual motion area, hMT+ between the 6-month and 9-month follow up.
Change in resting state connectivity 6 months Change in resting state connectivity in the visual cortex between baseline (0-months) and 6-months, assessed by resting state functional magnetic resonance imaging (BOLD signal)
Maintenance of resting state connectivity 9 months Maintenance of resting state connectivity in the visual cortex between 6-month and 9-month follow up, assessed by resting state functional magnetic resonance imaging (BOLD signal)
Trial Locations
- Locations (1)
Wellcome Centre For Integrative Neuroimaging, University of Oxford
🇬🇧Oxford, Oxfordshire, United Kingdom