Previous studies have shown that children suffering from developmental dyslexia have a deficit in categorical perception of speech sounds. The aim of the current study was to better understand the nature of this categorical perception deficit. In this study, categorical perception skills of children with dyslexia were compared with those of chronological age and reading level controls. Children identified and discriminated /do-to/ syllables along a voice onset time (VOT) continuum. Results showed that children with dyslexia discriminated among phonemically contrastive pairs less accurately than did chronological age and reading level controls and also showed higher sensitivity in the discrimination of allophonic contrasts. These results suggest that children with dyslexia perceive speech with allophonic units rather than phonemic units. The origin of allophonic perception in the course of perceptual development and its implication for reading acquisition are discussed.
Purpose-The claim that speech perception abilities are impaired in dyslexia was investigated in a group of 62 dyslexic children and 51 average readers matched in age.Method-To test whether there was robust evidence of speech perception deficits in children with dyslexia, speech perception in noise and quiet was measured using eight different tasks involving the identification and discrimination of a complex and highly natural synthetic 'pea'-'bee' contrast (copy synthesised from natural models) and the perception of naturally-produced words.Results-Children with dyslexia, on average, performed more poorly than average readers in the synthetic syllables identification task in quiet and in across-category discrimination (but not when tested using an adaptive procedure). They did not differ from average readers on two tasks of word recognition in noise or identification of synthetic syllables in noise. For all tasks, a majority of individual children with dyslexia performed within norms. Finally, speech perception generally did not correlate with pseudo-word reading or phonological processing, the core skills related to dyslexia.Conclusions-On the tasks and speech stimuli we used, most children with dyslexia do not appear to show a consistent deficit in speech perception.
Purpose: This study investigated whether adults with dyslexia show evidence of a consistent speech perception deficit by testing phoneme categorization and word perception in noise.Method: Seventeen adults with dyslexia and 20 average readers underwent a test battery including standardized reading, language and phonological awareness tests, and tests of speech perception. Categorization of a 'pea'/'bee' voicing contrast was evaluated using adaptive identification and discrimination tasks, presented in quiet and in noise, and a fixed-step discrimination task. Two further tests of word perception in noise were presented.Results: There were no significant group differences for categorization in quiet or noise, for across-and within-category discrimination as measured adaptively, or word perception, but average-readers showed better across-and within-category discrimination in the fixed-step discrimination. Individuals did not show consistent poor performance across related tasks.
Conclusions:The small number of group differences, and lack of consistent poor individual performance, suggests weak support for a speech perception deficit in dyslexia. It seems likely that at least some poor performances are attributable to non-sensory factors like attention. It may also be that some individuals with dyslexia have speech perceptual acuity that is at the lower end of the normal range and exacerbated by non-sensory factors.
Purpose-To determine whether children with dyslexia (DYS) are more affected than agematched average readers (AR) by talker and intonation variability when perceiving speech in noise.Method-Thirty-four DYS and 25 AR children were tested on their perception of consonants in naturally-produced consonant-vowel (CV) tokens in multi-talker babble. Twelve CVs were presented for identification in four conditions varying in the degree of talker and intonation variability. Consonant place (/bi/-/di/) and voicing (/bi/-/pi/) discrimination was investigated with the same conditions.Results-DYS children made slightly more identification errors than AR children but only for conditions with variable intonation. Errors were more frequent for a subset of consonants, generally weakly-encoded for AR children, for tokens with intonation patterns (steady and risefall) that occur infrequently in connected discourse. In discrimination tasks, which have a greater memory and cognitive load, DYS children scored lower than AR children across all conditions. Conclusions-Unusual intonation patterns had a disproportionate (but small) effect on consonant intelligibility in noise for DYS children but adding talker variability did not. DYS children do not appear to have a general problem in perceiving speech in degraded conditions, which makes it unlikely that they lack robust phonological representations.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.