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Dichotic Pitch:
A new stimulus distinguishes normal and dyslexic auditory function
Robert F. Dougherty*, Max S. Cynader*, Bruce H. Bjornson*#, Dorothy Edgell^, Deborah E. Giaschi*#
*University of British Columbia, Vancouver, BC, Canada
#British Columbia's Children's Hospital, Vancouver, BC, Canada
^University of Victoria and Queen Alexandra Centre for Children's Health,
Victoria, BC, Canada
Two patterns of appropriately filtered acoustic white noise can be binaurally fused by the human auditory system to extract pitch and location information that is not available to either ear alone. This phenomenon is called dichotic pitch. Here we present a new method for generating more effective and useful dichotic pitch stimuli. These novel stimuli allow the psychophysical assessment of dichotic pitch detection thresholds. We show that dichotic pitch detection is significantly impaired in individuals with developmental dyslexia, as compared to average readers. These results suggest a low-level auditory deficit associated with dyslexia and also demonstrate the potential value of our new dichotic pitch stimuli for assessment of auditory processing.
Supported by March of Dimes grant FY96-0479
& BC-MSF grant 95-36(95) to D.E.G.
This work was performed in the Department of Ophthalmology at British
Columbia's Children's Hospital, Vancouver, BC, V6H 3V4 Canada
Published in NeuroReport, 1998, 9(13). A pdf of the full paper is available.
For examples of the stimuli used in this study, see Dichotic Pitch Demos.