Neurophysiological evidence of auditory channel anomalies in developmental dysphasia
G. A. Stefanatos, G. G. Green and G. G. Ratcliff
University Department of Clinical Neurology, Radcliffe Infirmary, Oxford, England.
Steady-state auditory evoked responses to frequency-modulated tones were
obtained from normal children and two groups of children with developmental
language disorders (developmental dysphasia). Children with predominantly
expressive language impairment produced responses not different from normal
children, while children with primary receptive language impairment
produced responses that were markedly diminished, even absent. This
occurred in recordings from either cerebral hemisphere and at mean
frequency-modulation depths ranging from +/- 20 to +/- 100 Hz.
Pathophysiology of auditory mechanisms concerned with frequency-modulation
analysis are particularly associated with receptive developmental language
impairment and may underlie associated difficulties in speech perception.
