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Abstract:
Possible auditory spatial deficits in neglect were examined
by comparing the performance of 4 right brain-damaged (RBD)
patients with left visuospatial neglect, versus 4 RBD patients
without neglect, in three auditory tasks. The first task required
speeded discrimination of sound elevation, by moving a central
lever up or down according to the vertical position of a target
sound, regardless of its side. The other two tasks were
non-spatial, requiring either speeded pitch discrimination (moving
the central lever up for high pitch, down for low pitch) or speeded
target detection. The results demonstrate that neglect patients'
performance was impaired for left versus right auditory targets,
unlike RBD controls, only when the auditory task required spatial
coding of the target sound (the up/down spatial discrimination).
This demonstrates a selective deficit of auditory space perception
for the contralesional hemispace in neglect patients, while
avoiding the confounds (motor, visual and egocentric) of previous
studies on possible auditory deficits in neglect. Since auditory
space perception was impaired in the vertical dimension for the
contralesional hemispace, the observed deficit cannot be attributed
to a systematic rightward shift in sound localisation. Instead, the
results suggest increased spatial uncertainty in sound localisation
on the affected side.
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