Hemianopia, Homonymous, Hemianopsia, Occipital Lobe Infarct, Quadrantanopia, Stroke Hemorrhagic, Stroke, Ischemic, Vision Loss Partial, Visual Field Defect, Peripheral
Conditions
Keywords
occipital stroke, vision loss after stroke, vision recovery, vision restoration, partial vision loss
Brief summary
This project aims to develop a novel visual training paradigm for use in visually-intact participants and those sufferings from stroke-induced visual impairments. Our task design is built upon theories of statistical learning to reduce the overall training burden while still producing profound improvements to visual abilities. Efficacy will be first established in visually-intact controls before testing in stroke survivors to assess the feasibility of this form of learning in the damaged visual system.
Interventions
DEVICEVision Training and Learning Task
Participants will be seated at a computer, and will be shown a random-noise visual stimulus drifting in one of eight directions. Participants will be instructed to indicate the direction of motion they perceive using a Sony Access Controller or a computer keyboard. Sound cues during stimulus presentation will also be used to ensure participants are aware of stimulus onset during the training task. After several repetitions of this visual training, a second set of visual cues will be presented to evaluate participant's learning of the program. Responses will be provided in the same manner by input from the controller or the keyboard.
Sponsors
University of Rochester
Study design
Allocation
NON_RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
21 Years to 75 Years
Healthy volunteers
Yes
Inclusion criteria
Cortically Blind participants Inclusion criteria: * Between 21 and 75 years of age * Residents of the United States or Canada * Have successfully completed previous enrollment in Dr. Huxlin study (IRB #5966 or #75) * Exhibit unilateral stroke or stroke-like damage to primary visual cortex or its immediate afferent white matter sustained within the specified age range of 21 - 75 years (verified by MRI and/or CT scans) * Reliable visual field defects in both eyes (homonymous defects) as measured by Humphrey visual fields. This deficit must be large enough to enclose a 5-deg diameter visual stimulus. * Able to fixate on visual targets reliably for 1000ms within 1-deg of visual angle. * Willing, able, and competent to provide their own informed consent * Normal cognitive abilities and be able to understand written and oral instructions in English
Exclusion criteria
* Past or present ocular disease interfering with visual acuity * Best corrected visual acuity (BCVA) worse than 20/40 in either eye * Sustained documented or suspected damage to the dorsal Lateral Geniculate Nucleus * Presence of diffuse whole brain degenerative processes * History of traumatic brain injury * Any other brain damage deemed by study staff to potentially interfere with training ability or outcome measures * Documented history of drug/alcohol abuse * Currently taking neuroactive medications which would impact training, as determined by PI * Cognitive or seizure disorders * One-sided attentional neglect * Those who lack the competence or are otherwise unable to perform the visual training exercises as directed. Control participants Inclusion criteria: * Between 21 and 75 years of age * No history of neurological disorder. * Competent and responsible, as determined by the screening interview
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Explicit Learning - Response Time | Baseline | Reaction time (ms) when performing motion discriminations for the final stimulus of a statistically-linked triplet will be compared against reaction times for stimuli with identical motion directions, presented with alternative placement within a triplet. Comparisons will be made only for correct responses in the final 20% of overall testing session trials. |
| Implicit Learning - Triplet Familiarity | Baseline | Participant familiarity with statistically-linked triplets of motion will be assessed via a two-interval, forced-choice task. Familiarity will be measured as a percentage of comparisons in which the more prevalent triplet is selected as more familiar. Familiarity of high-probability, low-probability, and null-probability triplets will be compared following training. |
Countries
United States
Outcome results
None listed