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I. Gaudry, C. Cavezian, C. Perez, M. Obadia, O. Gout, S. Chokron; Training Hemianopes in Their Blind Hemifield: Comparison of Two Left Hemianopes on Detection and Categorisation Tasks. Invest. Ophthalmol. Vis. Sci. 2009;50(13):1438.
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© ARVO (1962-2015); The Authors (2016-present)
Recovery from long lasting visual field defect after primary visual cortex injury has scarcely been reported. Recently, Chokron et al. (2008) described an enlargement of the visual field in adult hemianopes, after specialized rehabilitation based on blindsight theories.
Following these same theories, we attempted to train high perceptual processes in the blind field of two left hemianopes through "active training" (i.e., a same/different judgement of two successive natural scene images, with feedback). RP had minimal sparing in his upper left visual field. ML had upper left minimal sparing on his right eye and lower-left minimal sparing on his left eye. As a control task, a "passive training" (i.e., colour frame judgement in the central visual field) was completed with a one-week delay from the active training. Training effects were evaluated in a categorization task of natural scene images and in a detection task of flashing dots. Both tasks were performed as pre- and post-training tests. In all tasks, stimuli were presented centrally or with a 3.5° eccentricity, and fixation was controlled with a video camera. In addition, the hemianopes performances were compared with 10 healthy controls.
The "active training" increased detection rates in the blind hemifield of both patients and showed slightly improved performance in the central-left visual field. Moreover patient ML showed higher detection rates for stimuli presented in the lower-left visual field but a lower detection rate for stimuli in the lower-right visual field. Patients performed similar to controls for upper left presentations. There was no improvement in categorization skills. Passive training did not lead to improvements.
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