Delayed detection of tonal targets in background noise in dyslexia.
Individuals with developmental dyslexia are often impaired in their ability to process certain linguistic and even basic non-linguistic auditory signals. Recent investigations report conflicting findings regarding impaired low-level binaural detection mechanisms associated with dyslexia. Binaural impairment has been hypothesized to stem from a general low-level processing disorder for temporally fine sensory stimuli. Here we use a new behavioral paradigm to address this issue. We compared the response times of dyslexic listeners and their matched controls in a tone-in-noise detection task. The tonal signals were either Huggins Pitch (HP), a stimulus requiring binaural processing to elicit a pitch percept, or a pure tone-perceptually similar but physically very different signals. The results showed no difference between the two groups specific to the processing of HP and thus no evidence for a binaural impairment in dyslexia. However, dyslexic subjects exhibited a general difficulty in extracting tonal objects from background noise, manifested by a globally delayed detection speed.
Chait
Maria
M
Neuroscience and Cognitive Science Program, Department of Linguistics, University of Maryland, College Park, MD 20742-7505, USA. mariac@wam.umd.edu
Eden
Guinevere
G
Poeppel
David
D
Simon
Jonathan Z
JZ
Hill
Deborah F
DF
Flowers
D Lynn
DL
D000161:Acoustic Stimulation; D000328:Adult; D001308:Auditory Perceptual Disorders / Q000150:complications / Q000503:physiopathology*; D004410:Dyslexia / Q000150:complications / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D009622:Noise; D010897:Pitch Discrimination / Q000502:physiology*