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Abstract:
Studies have consistently shown that the degree of
phonological awareness is the single best predictor of reading
success (Liberman & Shankweiler, 1978). Research suggests that
poor readers' difficulties with phonological processing may be due
to deficient phonetic encoding of phonological categories in
working memory (Brady, Mann & Schmidt, 1987). The resulting
lack of robust phonemic percepts would account for reading-disabled
children's difficulty with grapheme-to-phoneme correspondences. In
the present study, we use mismatch negativity (MMN) to examine the
phonological representations of two groups of good (n=15)and poor
readers (n=15) by comparing them on their ability to discriminate,
preattentively, between memory traces of speech sounds /ba/, /da/
and /ga/, built up using an oddball paradigm (viz., /ba/-/da/ and
/da/ -/ga/). Preliminary findings lend support to the behavioral
findings of Mody, Studdert-Kennedy & Brady (1997), in that the
poor readers revealed greater difficulty than normal readers,
discriminating between these phonetically similar, but
phonologically contrastive, speech sound pairs, as evident in the
subtle differences between the latency and amplitude measures of
the MMN responses of the two groups. Such early evidence of
phonetic influences has important implications for speech-specific
processes in auditory perception.
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