SPEECH-PERCEPTION DEFICITS IN POOR READERS - AUDITORY PROCESSING OR PHONOLOGICAL CODING

Poor readers are inferior to normal-reading peers in aspects of speech perception. Two hypotheses have been proposed to account for their de ficits: (i) a speech-specific failure in phonological representation a nd (ii) a general deficit in auditory ''temporal processing,'' such th at they cannot easily perceive the rapid spectral changes of formant t ransitions at the onset of stop-vowel syllables. To test these hypothe ses, two groups of second-grade children (20 ''good readers,'' 20 ''po or readers''), matched forage and intelligence, were selected to diffe r significantly on a /ba/-/da/ temporal order judgment (TOJ) task, sai d to be diagnostic of a temporal processing deficit. Three experiments then showed that the groups did not differ in: (i) TOJ when /ba/ and /da/ were paired with more easily discriminated syllables (/ba/-/sa/, /da/-/integral a/); (ii) discriminating nonspeech sine wave analogs of the second and third formants of /ba/ and /da/; (iii) sensitivity to brief transitional cues varying along a synthetic speech continuum. Th us, poor readers' difficulties with /ba/-/da/ reflected perceptual con fusion between phonetically similar, though phonologically contrastive , syllables rather than difficulty in perceiving rapid spectral change s. The results are consistent with a speech-specific, not a general au ditory, deficit. (C) 1997 Academic Press.