Effect of Visual Retraining on Visual Loss Following Visual Cortical Damage

University of Rochester280 enrolled

Overview

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.

Study Type

INTERVENTIONAL

Allocation

NON_RANDOMIZED

Purpose

TREATMENT

Masking

NONE

Enrollment

280

Conditions

Vision Loss Partial Hemianopia Hemianopia Homonymous Quadrantanopia

Interventions

Training in the Blind FieldOTHER

A computer software and chin-rest necessary to perform visual training will be loaned to each subject to be used at home. Subjects will perform one to two daily training sessions in their home, consisting of 200-300 trials each. The visual task performed repetitively will involve discriminating the direction of motion, the presence of motion, or the orientation of a visual stimulus (either a small cloud of dots or bars) located at a predetermined location in the blind field. The computer program will automatically create a record of patient performance during each home training session. Subjects will train daily (about 40-60 minutes total), 5 to 7 days per week for at least 3 and up to 12 months at a time.

Training in the Sighted FieldOTHER

This training will take place in lab at the University of Rochester Medical Center. Subject will perform one daily training session, consisting of 200-300 trials each. The visual task performed repetitively will involve discriminating the direction of motion, the presence of motion, or the orientation of a visual stimulus (either a small cloud of dots or bars) located at a predetermined location in the visual field. The computer program will automatically create a record of patient performance during each training session. Subjects will train daily (about 30-40 minutes total), 5 to 7 days per week for at 7 - 14 days.

Eligibility

Sex: ALLMin age: 17 YearsMax age: 75 YearsHealthy volunteers:

Medical Language ↔ Plain English

Cortically Blind Subject 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) * Persons who lack the competence or are otherwise unable to perform the visual training exercises as directed. Control Subject Inclusion Criteria: * Subjects must be between the ages of 17 and 75 years of age * Subjects must report no history of neurological disorder. * Subjects who are competent and responsible, as determined by the Principal Investigator. Control Subject Exclusion criteria: * Subjects who possess damage to the visual system * 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 * Best corrected visual acuity worse than 20/40 in either eye * 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) * Persons who lack the competence or are otherwise unable to perform the visual testing/training exercises as directed.

Outcomes

Primary Outcomes

Direction Discrimination Threshold

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.