JSLHR_58_1_107Supp1.pdf (266.23 kB)

Evidence for a General Auditory Processing Deficit in Developmental Dyslexia (Christmann et al.)

Download (266.23 kB)
journal contribution
posted on 01.02.2015, 00:00 by Corinna A. Christmann, Thomas Lachmann, Claudia Steinbrink
Purpose It is unknown whether phonological deficits are the primary cause of developmental dyslexia or whether they represent a secondary symptom resulting from impairments in processing basic acoustic parameters of speech. This might be due, in part, to methodological difficulties. Our aim was to overcome two of these difficulties: the comparability of stimulus material and task in speech versus nonspeech conditions.
Method In this study, the authors (a) assessed auditory processing of German vowel center stimuli, spectrally rotated versions of these stimuli, and bands of formants; (b) used the same task for linguistic and nonlinguistic conditions; and (c) varied systematically temporal and spectral parameters inherent in the German vowel system. Forty-two adolescents and adults with and without reading disabilities participated.
Results Group differences were found for all linguistic and nonlinguistic conditions for both temporal and spectral parameters. Auditory deficits were identified in most but not all participants with dyslexia. These deficits were not restricted to speech stimuli—they were also found for nonspeech stimuli with equal and lower complexity compared with the vowel stimuli. Temporal deficits were not observed in isolation.
Conclusion These results support the existence of a general auditory processing impairment in developmental dyslexia.

Funding

This study was supported by the German Research Foundation Project STE 1699/2-1. Many thanks are due to Margret Linner and Hanne Heindel for assistance with participant recruitment. Furthermore, we thank the Tranfer Centre for Neuroscience and Learning in Ulm, Germany; University of Ulm, Germany; and Petra Linner for supporting the data collection at the University of Ulm. We also thank Bernhard Schaaf-Christmann (University of Kaiserslautern) for programming the MATLAB script for producing the bands of formants stimuli, Martin Dirichs for his support in programming the experiment, and Bettina Brendel for the vowel recordings.

History