ESCA Workshop on Audio-Visual Speech Processing (AVSP'97) September 26-27, 1997 Rhodes, Greece

Audiovisual Speech Perception in Dyslexics: Impaired Unimodal Perception but no Audiovisual Integration Deficit

Ruth Campbell (1), A. Whittingham (1), U. Frith (1), Dominic W. Massaro (2), M. M. Cohen (2)

(1) University College London, University of California at Santa Cruz, CA, USA
(2) Department of Human Communication Science, University College London, UK

Dyslexic and control school students (mean age 13.5 years) were tested using a series of unimodal and bimodal speechtokens; ba,va,tha,da and ga in every combination and unimodally. They made significantly more errors than controls to unimodal auditory and unimodal visual tokens. Their integration of audiovisual speech was not significantly impaired, but it did show a different function than that of controls, reflecting the anomalous unimodal processing functions. These data fit recent suggestions that magnocellular function is impaired in dyslexia. They fit less easily both with auditory temporal processing deficit theories or with theories of defective phonemic processing . A general 'integration-deficit' theory (Paulesu etal, 1996) is not supported by these data.

Full Paper

Bibliographic reference.  Campbell, Ruth / Whittingham, A. / Frith, U. / Massaro, Dominic W. / Cohen, M. M. (1997): "Audiovisual speech perception in dyslexics: impaired unimodal perception but no audiovisual integration deficit", In AVSP-1997, 85-88.