Use of Temporal Envelope Cues by Children With Developmental Dyslexia This study evaluates the ability to process auditory temporal-envelope cues in a group of 6 children with dyslexia (mean age: 10;10 years;months). To address this issue, we measured (a) temporal modulation transfer functions (TMTFs), that is, the detection thresholds of sinusoidal amplitude modulation (SAM) applied to a white noise carrier, ... Research Article
Research Article  |   December 01, 2000
Use of Temporal Envelope Cues by Children With Developmental Dyslexia
 
Author Affiliations & Notes
  • Christian Lorenzi
    Laboratoire de Psychologie Expérimentale Boulogne-Billancourt, France
  • Annie Dumont
    Hôpital Robert Debré Paris, France
  • Christian Füllgrabe
    Laboratoire de Psychologie Expérimentale Boulogne-Billancourt, France
  • Corresponding author: e-mail: lorenzi@psycho.univ-paris5.fr
  • Contact author: Christian Lorenzi, Laboratoire de Psychologie Expérimentale, UMR CNRS 8581, UFR Institut de Psychologie, Université René Descartes, Paris V. 71, Avenue Edouard Vaillant, 92774 Boulogne- Billancourt, France. Email: lorenzi@psycho.univ-paris5.fr
    Contact author: Christian Lorenzi, Laboratoire de Psychologie Expérimentale, UMR CNRS 8581, UFR Institut de Psychologie, Université René Descartes, Paris V. 71, Avenue Edouard Vaillant, 92774 Boulogne- Billancourt, France. Email: lorenzi@psycho.univ-paris5.fr×
Article Information
Hearing & Speech Perception / Acoustics / Language Disorders / Reading & Writing Disorders / Hearing / Research Articles
Research Article   |   December 01, 2000
Use of Temporal Envelope Cues by Children With Developmental Dyslexia
Journal of Speech, Language, and Hearing Research, December 2000, Vol. 43, 1367-1379. doi:10.1044/jslhr.4306.1367
History: Received September 20, 1999 , Accepted July 25, 2000
 
Journal of Speech, Language, and Hearing Research, December 2000, Vol. 43, 1367-1379. doi:10.1044/jslhr.4306.1367
History: Received September 20, 1999; Accepted July 25, 2000

This study evaluates the ability to process auditory temporal-envelope cues in a group of 6 children with dyslexia (mean age: 10;10 years;months). To address this issue, we measured (a) temporal modulation transfer functions (TMTFs), that is, the detection thresholds of sinusoidal amplitude modulation (SAM) applied to a white noise carrier, as a function of modulation frequency, fm (fm was 4, 16, 64, 256, and 1024 Hz) and (b) identification performance for vowel-consonantvowel (VCV) stimuli over 5 sessions. VCV stimuli were either unprocessed or digitally processed to remove the original spectral information, resulting in a timevarying speech envelope amplitude modulating a noise carrier. The same tests were conducted in 6 normal control children (mean age: 11;6 years;months) and 6 normal control adults (mean age: 24;8 years;months). SAM thresholds were similar in normal children and adults. For both normal groups, TMTFs were low pass in shape and showed low between-listener variability. TMTFs measured in children with dyslexia showed higher between-listener variability: TMTFs were band pass in 2 children, flat in 1 child, and low pass in the 3 others. Overall, SAM thresholds were higher in children with dyslexia than in normal children at fm=4 and 1024 Hz. Unprocessed-speech identification performance was nearly perfect in normal children and adults, and impaired in children with dyslexia. "Speech-envelope noise" identification performance was poorer in normal children and children with dyslexia than in normal adults. Performance improved across sessions in normal children and adults, but remained constant in children with dyslexia. Compared to normal children, children with dyslexia showed poorer reception of voicing, manner, and place of articulation for unprocessed speech and poorer reception of voicing for "speech-envelope noise. " Taken together, these results support the hypothesis that some children with dyslexia may show abnormal auditory temporal-envelope processing. Such a deficit, in turn, may explain the difficulties of children with dyslexia with speech perception.

Acknowledgments
The authors are indebted to the children and their families for their kind participation in this study. The authors are also indebted to Carolyn Drake, Craig Formby, Larry Humes, and two anonymous reviewers for constructive comments on an earlier version of the manuscript.
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