AUDITORY TEMPORAL PERCEPTION DEFICITS IN THE READING-IMPAIRED - A CRITICAL-REVIEW OF THE EVIDENCE

We assess evidence and arguments brought forward by Tallal (e.g., 1980 ) and by the target paper (Fanner & Klein, 1995) for a general deficit in auditory temporal perception as the source of phonological deficit s in impaired readers. We argue that (1) errors in temporal order judg ment of both syllables and tones reflect difficulty in identifying sim ilar (and so readily confusable) stimuli rapidly, not in judging their temporal order; (2) difficulty in identifying similar syllables or to nes rapidly stem from independent deficits in speech and nonspeech dis criminative capacity, not from a general deficit in rate of auditory p erception; and (3) the results of dichotic experiments and studies of aphasics purporting to demonstrate left-hemisphere specialization for nonspeech auditory temporal perception are inconclusive. The paper sup ports its arguments with data from a recent control. study. We conclud e that, on the available evidence, the phonological deficit of impaire d readers cannot be traced to any co-occurring nonspeech deficits so f ar observed and is phonetic in origin, but that its full nature, origi n, and extent remain to be determined.