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Abstract:
Previous research has shown relatively mild phonemic
perception deficits on auditory comprehension tests in aphasia. In
these studies, aphasic subjects listened to a word, then selected
the picture that best matched the word from a four-choice array.
The choices included the correct target (BEAR), a phonemic foil
(PEAR), a semantic foil (WOLF), and an unrelated foil (GRAPES). On
that task, aphasics performed well overall, and on average
committed more semantic errors than phonemic. The present study
evaluated whether phonemic processing deficits in aphasia could be
revealed using a more sensitive measure. To that end, we redesigned
the original task, providing multiple phonemic and semantic foils
for each target word. In the new task, half the trials presented
all phonemic foils (i.e., BUN/GUN/RUN/SUN), while the other trials
presented all semantic foils (i.e., SOCK/HAT/SCARF/GLOVE). Six
aphasics were tested on both tasks. The new task proved to be a
more sensitive measure of both phonemic and semantic deficits, as 5
of the 6 subjects committed errors on the new task, whereas only
two committed errors on the original task. Replicating previous
work, aphasics committed almost twice as many semantic errors than
phonemic (12% vs. 7%). This evidence provides further support to
the idea that phonemic perception deficits make only a small
contribution to auditory comprehension problems in aphasia.
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