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Abstract:
If auditory and spatial representations are spatially
co-registered, one might expect auditory processing to be
influenced by the location to which visual attention is directed.
We examined this question, using an auditory localization task in
which the location of gaze was manipulated while head and body
position were held constant. Subjects included three patients with
right hemisphere stroke who were asked to identify the speaker from
which white noise emanated; stimuli were presented from one of
seven speakers arranged in a semi-circle in front of the subject (3
in the right and left hemispaces and 1 in the midline). As expected
given their right hemisphere lesions, while gazing at the midline
speaker, patients were less accurate localizing sound in the
contralesional (left) hemispace (23% errors averaged across
subjects) as compared to the right hemispace (4% errors; for all
contrasts, p's <.01). When gazing at the speaker 30i to the left
of the midline speaker, performance in the left hemispace improved
(3% errors) whereas performance in the right hemispace deteriorated
(25% errors). In contrast, when gazing at the speaker 30° right
of the midline speaker, performance was better in the right (2%
errors) than the left hemispace (31% errors). Significant effects
of eye position were noted in all three subjects when analyzed
individually. These data demonstrating significant differences in
sound localization as a function of eye position suggest that
auditory and visual attention may be linked to a common spatial
coordinate system.
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