In 36 patients with left unilateral spatial neglect due to right hemispheric damage, a sound lateralization test was conducted as an auditory task, using a Rhion audiometer AA-75. The test results were analyzed in relation to the score calculated from the results of a Behavioural inattention test (a visual task). In the sound lateralization test, the left/right ratio of the inter-aural time difference discrimination threshold was determined, and the percent increase was calculated in the left inter-aural time difference discrimination threshold relative to that on the right. As a result, no significant correlation existed between the sum scores of a Behavioural inattention test (usual tasks and/or behavioural tasks) and sound lateralization test scores in all the unilateral spatial neglect patients. And the left/right ratio of the inter-aural time difference discrimination threshold did not correlate significantly with the score calculated from any subtests of the Behavioural inattention test. Accordingly, we found that the severity of auditory tasks was not always consistent with that of visual tasks in unilateral spatial neglect cases. This suggests that patients with severe unilateral neglect sometimes show only mild abnormalities in auditory tasks. In such cases, the utilization of auditory stimuli in treatment can compensate for unilateral neglect symptoms.
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