ASA 129th Meeting - Washington, DC - 1995 May 30 .. Jun 06

4aSC12. Reading disability: A deficit in the processing of rapid spectral changes or in phonological coding?

Maria Mody

Dept. of Otolaryngol., Kennedy Ctr., Albert Einstein College of Medicine, 1300 Morris Park, Bronx, NY 10461

Michael Studdert-Kennedy

Haskins Labs., New Haven, CT 06511

Reading-impaired children have been said to suffer from an auditory deficit, indexed by difficulties in processing formant transitions [P. Tallal, Brain & Lang. 9, 182--198 (1980)]. Having established that poor readers (n=20) made significantly more errors than good readers (n=20) on discrimination between stop-vowel syllables, contrasting in initial F[sub 2] and F[sub 3] transitions (/ba/ and /da/), but not between nonspeech sinewave analogs of F[sub 2] and F[sub 3], the present study compared the same groups on identification of (i) a /se(small capital eye)-ste(small capital eye)/ synthetic continuum, where F[sub 1] transition cued the contrast, and (ii) two hybrid /su--(sh)u/ continua, each biased toward one end (/s/ or /(sh)/) of a synthetic fricative series by the formant transitions of naturally spoken vowels. Poor readers did not differ from good readers in phoneme boundaries, but did exhibit shallower identification functions, significantly so on the fricative continua. The results do not support the hypothesized auditory deficit: Less consistent discrimination or identification by poor readers on speech tasks but not on the nonspeech control task, suggests phonological rather than auditory difficulties.