| Research Abstract |
Prism adaptation (PA) with wedge prisms, which produce 10-degree rightward shift of the visual scene, was applied to patients with unilateral spatial neglect During prism exposure, a single target was presented at one of the five locations, ie., -10, -5, 0, +5, +10 deg from the midsagittal plane on the LCD monitor, This technique was expected to make the patients with severe neglect to reach multiple locations and increase the effectiveness of PA. However, the PA effect was smaller than that reported earlier, which may have resulted from a single trial. The original technique described by Bossetti, et. al. (1998) used two targets, in which patients with severe neglect often failed to find the left target To overcome this difficulty, two targets were presented with a line drawn between them. A patient with severe neglect was able to find the left-side target during prism exposure. After PA, he became to trace a line to the left endpoint, and showed marked improvement of line bisection.
In total, PA was applied to 14 patients with neglect, in whom only five patients snowed a statistically significant improvement of neglect A patient with severe chronic neglect achieved a total score of 127 in the Behavioural Inattention test after PA, compared with that of 83 before PA In the remaining four patients, however,improvement was limited to a small degree or to a single test of neglect PA was effective also for a patient with a lesion that damaged the occipital lobe largely and the parietal lobe partially, which was contradicting to the result of Serino, et. al. (2006). As PA has little side effect, it should be applied to any patients with neglect in the course of comprehensive rehabilitation. Some modification of target presentation is necessary during prism exposure.
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