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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.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Experimental: Cortically Blind (CB) Subjects | Experimental | Cortically Blind subjects will be enrolled to perform a daily home visual training task. |
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| Normative Comparator: Control Subjects | No Intervention | Healthy control subjects will be recruited to collect normative data by which to compare test results from CB subjects. No home training will be asked. |
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Training in the Blind Field | Device | 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. |
| Measure | Description | Time Frame |
|---|---|---|
| Change in Mean 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 with respect to the stimulus. These assessments will be based on what can be reliably detected at a 72-75% correct level of performance on our 2AFC task, with task difficulty adjusted on a 3:1 staircase. The degrees of visual angle for the stimulus vary from 90 degrees (fully vertical) to 0.1 degrees (virtually overlapping the horizontal axis). These measures of change will be evaluated baseline and at each subsequent visit to the laboratory; minimally from baseline to 4-6 months, then baseline to 8-12 months from start of training | Baseline to 4-6 months |
| Change in Mean 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 with respect to the stimulus. These assessments will be based on what can be reliably detected at a 72-75% correct level of performance on our 2AFC task, with task difficulty adjusted on a 3:1 staircase. The degrees of visual angle for the stimulus vary from 90 degrees (fully vertical) to 0.1 degrees (virtually overlapping the horizontal axis). These measures of change will be evaluated baseline and at each subsequent visit to the laboratory; minimally from baseline to 4-6 months, then baseline to 8-12 months from start of training | Baseline to 8-12 months |
| Change in Mean Direction Integration Threshold | This will measure the change in ability of subjects to integrate across a range of motion directions measured in degrees of visual angle, with respect to the stimulus. These assessments will be based on what range of motion directions can be reliably integrated at a 72-75% correct level of performance on our 2AFC task, with task difficulty adjusted on a 3:1 staircase. The degrees of visual angle for the stimulus vary from 90 degrees (fully vertical) to 0.1 degrees (virtually overlapping the horizontal axis) . These measures of change will be evaluated baseline and at each subsequent visit to the laboratory; minimally from baseline to 4-6 months, then baseline to 8-12 months from start of training. |
| Measure | Description | Time Frame |
|---|---|---|
| Humphrey 10-2 and 24-2 perimetry | The investigators will measure the change in visual sensitivity (measured in decibels) at all locations tested by the system. These measures will be evaluated at baseline and at each subsequent visit to the laboratory; minimally from baseline to 4-6 months, then baseline to 8-12 months from start of training. | Baseline to 4-6 months |
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Cortically Blind Subjects
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Exclusion:
Control Subjects (n = 50)
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| Name | Role | Phone | Extension | |
|---|---|---|---|---|
| Evan Burr | Contact | 585-275-5234 | Evan_Burr@urmc.rochester.edu |
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| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| University of Rochester Medical Center | Recruiting | Rochester | New York | 14642 | United States |
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| ID | Term |
|---|---|
| D001766 | Blindness |
| D006423 | Hemianopsia |
| D000083242 | Ischemic Stroke |
| D019575 | Blindness, Cortical |
| ID | Term |
|---|---|
| D014786 | Vision Disorders |
| D012678 | Sensation Disorders |
| D009461 | Neurologic Manifestations |
| D009422 | Nervous System Diseases |
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| Baseline to 4-6 months |
| Change in Mean Direction Integration Threshold | This will measure the change in ability of subjects to integrate across a range of motion directions measured in degrees of visual angle, with respect to the stimulus. These assessments will be based on what range of motion directions can be reliably integrated at a 72-75% correct level of performance on our 2AFC task, with task difficulty adjusted on a 3:1 staircase. The degrees of visual angle for the stimulus vary from 90 degrees (fully vertical) to 0.1 degrees (virtually overlapping the horizontal axis) . These measures of change will be evaluated baseline and at each subsequent visit to the laboratory; minimally from baseline to 4-6 months, then baseline to 8-12 months from start of training. | Baseline to 8-12 months |
| Change in Mean Contrast Sensitivity for Direction | 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. The investigators will measure the luminance contrast, measured in percentage of contrast with respect to the stimulus, that can be reliably detected at a 72-75% correct level of performance. Contrast will vary between 100% (maximum contrast of black on grey) and 0.1% (minimum contrast visible of grey-on-grey) based on subject performance and a 3:1 staircase. These measures of change will be evaluated baseline and at each subsequent visit to the laboratory; minimally from baseline to 4-6 months, then baseline to 8-12 months from start of training. | Baseline to 4-6 months |
| Change in Mean Contrast Sensitivity for Direction | 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. The investigators will measure the luminance contrast, measured in percentage of contrast with respect to the stimulus, that can be reliably detected at a 72-75% correct level of performance. Contrast will vary between 100% (maximum contrast of black on grey) and 0.1% (minimum contrast visible of grey-on-grey) based on subject performance and a 3:1 staircase. These measures of change will be evaluated baseline and at each subsequent visit to the laboratory; minimally from baseline to 4-6 months, then baseline to 8-12 months from start of training. | Baseline to 8-12 months |
| Change in Mean Contrast Sensitivity for Static Orientation | 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. The investigators will measure the luminance contrast, measured in percentage of contrast with respect to the stimulus, that can be reliably detected at a 72-75% correct level of performance. Contrast will vary between 100% (maximum contrast of black on grey) and 0.1% (minimum contrast visible of grey-on-grey) based on subject performance and a 3:1 staircase. These measures of change will be evaluated baseline and at each subsequent visit to the laboratory; minimally from baseline to 4-6 months, then baseline to 8-12 months from start of training. | Baseline to 4-6 months |
| Change in Mean Contrast Sensitivity for Static Orientation | 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. The investigators will measure the luminance contrast, measured in percentage of contrast with respect to the stimulus, that can be reliably detected at a 72-75% correct level of performance. Contrast will vary between 100% (maximum contrast of black on grey) and 0.1% (minimum contrast visible of grey-on-grey) based on subject performance and a 3:1 staircase. These measures of change will be evaluated baseline and at each subsequent visit to the laboratory; minimally from baseline to 4-6 months, then baseline to 8-12 months from start of training. | Baseline to 8-12 months |
| Humphrey 10-2 and 24-2 perimetry | The investigators will measure the change in visual sensitivity (measured in decibels) at all locations tested by the system. These measures will be evaluated at baseline and at each subsequent visit to the laboratory; minimally from baseline to 4-6 months, then baseline to 8-12 months from start of training. | Baseline to 8-12 months |
| Goldmann perimetry | The investigators will measure the change in area of vision (degrees squared) as encompassed by each isopter, measured by one of 3 different light stimuli. The 3 isopters which will be compared are: I2e 1asb, 0.25 mm^2 I4e 10asb, 0.25 mm^2 V4e 1000asb, 64 mm^2 These measures will be evaluated at baseline and at each subsequent visit to the laboratory; minimally from baseline to 4-6 months, then baseline to 8-12 months from start of training. | Baseline to 4-6 months |
| Goldmann perimetry | The investigators will measure the change in area of vision (degrees squared) as encompassed by each isopter, measured by one of 3 different light stimuli. The 3 isopters which will be compared are: I2e 1asb, 0.25 mm^2 I4e 10asb, 0.25 mm^2 V4e 1000asb, 64 mm^2 These measures will be evaluated at baseline and at each subsequent visit to the laboratory; minimally from baseline to 4-6 months, then baseline to 8-12 months from start of training. | Baseline to 8-12 months |
| MAIA Visual Field Perimetry | The investigators will measure the change in visual sensitivity (measured in decibels) at all locations tested by the system. These measures will be evaluated at baseline and at each subsequent visit to the laboratory; minimally from baseline to 4-6 months, then baseline to 8-12 months from start of training. | Baseline to 4-6 months |
| MAIA Visual Field Perimetry | The investigators will measure the change in visual sensitivity (measured in decibels) at all locations tested by the system. These measures will be evaluated at baseline and at each subsequent visit to the laboratory; minimally from baseline to 4-6 months, then baseline to 8-12 months from start of training. | Baseline to 8-12 months |
| D005128 |
| Eye Diseases |
| D012816 | Signs and Symptoms |
| D013568 | Pathological Conditions, Signs and Symptoms |
| D020521 | Stroke |
| D002561 | Cerebrovascular Disorders |
| D001927 | Brain Diseases |
| D002493 | Central Nervous System Diseases |
| D014652 | Vascular Diseases |
| D002318 | Cardiovascular Diseases |