Recovery from occipital stroke: a self-report and an inquiry into visual processes.
This report summarizes the behavioural effects of a right occipital stroke in the author. An upper left quandrantanopia resolved over the first 50 poststroke days to leave a scotoma that included the left upper quadrant of the fovea and extended upwards about 6 degrees and lateral about 15 degrees. There was no further reduction in size over the next 4 years. In the early stages of recovery there was an inability to detect consciously either the presence of objects or their motion, except upon reflection once an object entered the intact visual field. This has been referred to previously as blindsight. On about the fourth day poststroke, part of the scotoma became visually active, producing a scintillating aura, which remains. Shortly thereafter colour perception returned in the scotoma, as did motion detection. Although there was little additional change in the field defect after 2 months, the author's visual abilities have continued to improve, in large part because of a shift in fixation such that information at the centre of the visual field now falls about 1.5 degrees into the lower right portion of the fovea. The implications of the visual and behavioural changes are discussed in the context of multiple visual systems and with respect to recovery of function.
Kolb
B
B
Dept of Psychology, University of Lethbridge, AB, Canada.
D000328:Adult; D001288:Attention / Q000502:physiology; D002544:Cerebral Infarction / Q000503:physiopathology*; D004292:Dominance, Cerebral / Q000502:physiology; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009778:Occipital Lobe / Q000503:physiopathology*; D014793:Visual Cortex / Q000503:physiopathology*; D014794:Visual Fields / Q000502:physiology; D014795:Visual Pathways / Q000503:physiopathology; D014796:Visual Perception / Q000502:physiology*