Effect of Visual Retraining on Visual Loss Following Visual Cortical Damage
Overview
- Phase
- Not Applicable
- Intervention
- Not specified
- Conditions
- Vision Loss Partial
- Sponsor
- University of Rochester
- Enrollment
- 280
- Locations
- 1
- Primary Endpoint
- Direction Discrimination Threshold
- Status
- Completed
- Last Updated
- last year
Overview
Brief Summary
This project is intended to collect data using standard clinical tests and psychophysics to quantify the effect of visual cortical damage on the structure of the residual visual system, visual perception, spatial awareness, and brain function. The investigators will also assess the effect of intensive visual retraining on the residual visual system, processing of visual information and the use of such information in real-world situations following damage. This research is intended to improve our understanding of the consequences of permanent visual system damage in humans, of methods that can be used to reverse visual loss, and of brain mechanisms by which visual recovery is achieved.
Investigators
Krystel Huxlin
Professor
University of Rochester
Eligibility Criteria
Inclusion Criteria
- •Subjects between the ages of 17 and 75, who have sustained damage to primary visual cortex at age 17 or later, and are rendered blind over a portion of their visual field.
- •Subjects must have some intact visual cortical areas (other than primary visual cortex) in the damaged brain hemisphere. This assessment will be made from MRI or CT scans of the subject's head, which will be obtained via standard release from their neurologist.
- •Subjects who demonstrate a clear deficit in either simple or complex visual perception in portions of their visual field.
- •Subjects who are competent and responsible, as determined by the Principal Investigator.
- •Subjects who will receive retinal electrophysiology (mfERG) testing must have a report from their ophthalmologist stating that they are able to receive dilating drops
- •Cortically Blind Subject
Exclusion Criteria
- •Subjects who do not possess damage of primary visual cortex or its immediate afferents
- •Subjects who are suffering from an active disease process involving their nervous system.
- •Subjects who are unable to fixate visual targets precisely with their eyes
- •Subjects who have unreliable vision fields from prior testing indicated by greater than 20% fixation losses, false positives or false negatives
- •Best corrected visual acuity worse than 20/40 in either eye
- •Impaired foveal sensitivity as indicated by visual field tests
- •Presence of vision loss from ocular disease or disorder
- •Presence of bilateral visual acuity loss from any source
- •Subjects who are suffering from one-sided attentional neglect
- •Subjects who have impaired auditory thresholds that would influence test results and training efficacy (all our testing and training involves sound as a cue for trial/stimulus onset or as feedback)
Outcomes
Primary Outcomes
Direction Discrimination Threshold
Time Frame: Baseline, 4-months, 12-months
For each subject, the investigators will measure the change in ability to detect differences in the motion direction of visual stimuli relative to horizontal, measured in degrees of visual angle. These assessments will be based on what can be reliably detected at a 72-75% correct level of performance. These measures of change will be evaluated baseline and at each subsequent visit to the laboratory; minimally from baseline to 4-months, then baseline to 12-months from start of training.
Direction Integration Threshold
Time Frame: Baseline to 4-months, 12-months
This will measure the change in ability of subjects to integrate across a range of motion directions measured in degrees of visual angle. These assessments will be based on what range of motion directions can be reliably integrated at a 72-75% correct level of performance. These measures of change will be evaluated baseline and at each subsequent visit to the laboratory; minimally from baseline to 4-months, then baseline to 12-months from start of training.
Contrast Sensitivity for Direction
Time Frame: Baseline, 4-months, 12-months
Assessment of visual perception transfer to untrained psychophysical tasks of contrast sensitivity for direction discrimination. This is a change metric as transfer must be compared from pre- to post- each course of training. For each subject, the investigators will measure the ability to correctly detect the motion direction of visual stimuli that are also varying in contrast against a grey background. We will measure the luminance contrast that can be reliably detected at a 72-75% correct level of performance. These measures of change will be evaluated baseline and at each subsequent visit to the laboratory; minimally from baseline to 4-months, then baseline to 12-months from start of training.
Contrast Sensitivity for Static Orientation
Time Frame: Baseline, 4-months, 12-months
Assessment of visual perception transfer to untrained psychophysical tasks of contrast sensitivity for static orientation discrimination. This is a change metric as transfer must be compared from pre- to post- each course of training. For each subject, the investigators will measure the ability to correctly detect the orientation of non-moving visual stimuli that vary in contrast against a grey background. We will measure the luminance that can be reliably detected at a 72-75% correct level of performance. These measures of change will be evaluated baseline and at each subsequent visit to the laboratory; minimally from baseline to 4-months, then baseline to 12-months from start of training.
Secondary Outcomes
- Goldmann perimetry(Baseline, 4-months, 12-months)
- MAIA Visual Field Perimetry(Baseline, 4-months, 12-months)
- Humphrey 10-2 and 24-2 perimetry(Baseline, 4-months, 12-months)