Clarifying the speech perception deficits of children and adults with dyslexia
This is an HCSNet sponsored seminar
Professor Valerie Hazan
UCL Speech, Hearing and Phonetic Sciences at University College London (UCL)
Friday 5th September
Seminar Room 2 (Rm 31), Psychology Building SO6
In this talk, I will present results of a recent study on speech perception in dyslexia carried out in collaboration with Stuart Rosen and Souhila Messaoud-Galusi. 62 children with a formal diagnosis of dyslexia and 51 children of average reading ability were presented with a range of tests aimed at assessing their identification of a voicing contrast (PEA-BEE) presented in clear and in noise, and their discrimination of the same contrast using both fixed and adaptive procedures. They were also tested on their perception of real words presented in noise, and on standardised tests. The same test battery was also presented to adults with dyslexia and controls.
We expected that if dyslexic children have poorly-defined phonemic categories, they should make more errors in the identification of speech sounds in noisy situations. Also, if poor discrimination is due to a specific perceptual deficit, we would expect performance to be consistently poor across different testing procedures for a given continuum. Our analyses suggest that there were some differences in performance between the two groups of children in the ‘PEA-BEE’ tests, but the dyslexics and average-readers did not differ significantly on ‘natural speech in noise’ tests. Also, when we examined individual data, we found that a majority of children with dyslexia performed within norms, and that there was little evidence of consistent patterns of performance across fixed and adaptive discrimination tasks. These results are not consistent with there being a clear, causal relation between difficulties in discriminating speech sounds and dyslexia.
Valerie Hazan is currently a professor in Speech Sciences at University College London (UCL). She has spent most of her working life at UCL and was Head of the Department of Phonetics and Linguistics from 2000 to 2007. Her research interests are in the area of speech perception. In recent years, she has carried out research on speech perception development in typically-developing children and children with dyslexia, on speaker variability and its impact on speech perception, on audiovisual perception in L1 and L2 speakers. She is currently spending some of her sabbatical term at MARCS (UWS), with funding from the HCSnet International Speaker programme.