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Abstract:
Abstract: Eleven patients showing unilateral neglect on
visual tasks were tested. We presented sounds over headphones, and
manipulated the perceived location of the sounds by adding a slight
delay to the sounds in one ear (interaural time delay). Listeners
judged whether the sounds were to the left or right of midline in a
forced choice procedure. To determine the perceived midline the
location of the sounds was adjusted using two interleaved one-up
one-down adaptive staircases. It was found that eight of the 11
neglect patients had midlines within the normal range, or had
deviations consistent with a peripheral hearing loss. The shifts of
the remaining three did not shown a pattern that correlated with
their performance on the visual measures. In addition to measuring
perceived midlines, we were able to obtain an estimate of ability
to discriminate different positions in space by deriving the
underlying psychometric functions. This was also within the range
of age-matched controls. The failure of this experiment to show any
problems in the perception of spatial location contrasts strongly
with other experiments done with the same patients showing an
extremely marked deficit in making comparisons over time when
comparisons had to be made between different sounds. This suggests
that time, rather than space, might be more important in auditory
aspects of neglect, and perhaps in auditory attention in
general.
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