Perception of voice and tone onset time continua in children with dyslexiawith and without attention deficit/hyperactivity disorder

Tasks assessing perception of a phonemic contrast based on voice onset time (VOT) and a nonspeech analog of a VOT contrast using tone onset time (TOT) were administered to children (ages 7.5 to 15.9 years) identified as havin g reading disability (RD; n = 21), attention deficit/hyperactivity disorder (ADHD; n = 22), comorbid RD and ADHD (n = 26), or no impairment (NI; n = 2 6). Children with RD, whether they had been identified as having ADHD or no t. exhibited reduced perceptual skills on both tasks as indicated by shallo wer slopes on category labeling functions and reduced accuracy even at the endpoints of the series where cues are most salient. Correlations between p erformance on the VOT task and measures of single word decoding and phonemi c awareness were significant only in the groups without ADHD. These finding s suggest that (a) children with RD have difficulty in processing speech an d nonspeech stimuli containing similar auditory temporal cues. (b) phoneme perception is related to phonemic awareness and decoding skills. and (c) th e potential presence of ADHD needs to be taken into account in studies of p erception in children with RD. (C) 2001 Academic Press.