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Jennifer M. Williams, Mary Hayhoe, Krystel Huxlin; Training-induced perceptual recovery after visual cortical stroke. Journal of Vision 2004;4(11):90. doi: 10.1167/4.11.90.
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© ARVO (1962-2015); The Authors (2016-present)
Visual cortical strokes are thought to cause impairments that are largely permanent1,2,3. We recently demonstrated visual recovery in cats following intensive visual discrimination retraining with random dot stimuli4. We hypothesized that therapy designed to stimulate higher-level visual cortical areas might improve visual sensitivity in humans with V1 damage and might even transfer to every-day visual tasks. Two patients, one hemianopic and one quadrantanopic, were recruited one year after a visual cortical stroke. They were taught to self-administer a two-alternative, forced-choice visual discrimination task, which they performed daily at home over several months and which required them to discriminate the global direction of motion (left or right) of an increasingly complex random dot stimulus placed within their blind visual field. The hemianopic patient progressed from no conscious perception of the random dot stimulus and direction range thresholds ∼0° to conscious perception of the stimulus and near-normal thresholds averaging 252+42° after 89 training sessions. The quadrantanopic patient initially perceived 1/8th of the training stimulus with threshold of ∼164° but ended perceiving the whole stimulus with thresholds averaging 258+19° after 56 training sessions. Recovery was restricted to the visual field locations retrained. Both patients' ability to detect and track moving objects in a realistic virtual environment improved significantly in their retrained (but not untrained) visual fields, suggesting that retraining in perception of complex motion stimuli transferred to everyday situations involving moving objects. Overall, our results show that intensive training with random dot stimuli can improve visual function in patients with V1 damage.
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