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Abstract:
There is an ongoing debate concerning the role of early
sensory processing in the complex cognitive task of reading.
Although functional brain imaging studies comparing reading in deaf
and hearing individuals have provided useful information, they have
been limited to studies of American Sign Language users. No studies
have utilized Cued Speech which, unlike ASL, represents the signed
version of spoken English and visually conveys spoken language at
the phonemic level. In this study we used functional magnetic
resonance imaging to determine the degree to which reading
mechanisms differ between two different communication modes, Spoken
and Cued English. Hearing subjects fluent in Spoken and Cued
English performed three tasks: sound deletion, single word reading
and fixation. Areas activated by both Spoken and Cued English
during single word reading included cerebellum, MI, SMA, insula and
STG. This latter finding in the superior temporal gyrus is
intriguing because no vocalization was made during cued responses,
indicating activation of this region in the absence of auditory
feedback. Phonological processing was identified by contrasting
sound deletion and word reading in both output conditions. Sound
deletion requires sublexical phonological analysis to a greater
extent than does reading. Common involvement of left inferior
parietal, bilateral temporal and extrastriate areas was observed,
demonstrating an output modality independent system for
phonological processing in individuals with intact hearing.
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