measures to education or training within the normal range remain to be developed. Even in situations in which methods from neuroscience can be used to diagnose learning needs—for example, in imaging diagnosis of dyslexia—behavioral methods are much simpler to use.

children who have trouble understanding spoken language have major deficits in their ability to recognize some rapidly successive phonetic elements in speech and similar impairments in detecting rapid changes in nonspeech sounds. The investigators trained a group of these children in computer “games” designed to cause improvement in auditory temporal processing skills. Following 8 to 16 hours of training over a 20-day period, the children improved markedly in their ability to recognize fast sequences of speech stimuli. In fact, their language was notably enhanced. (See Buonomano and Merzenich [1998] and Fitch, Miller, and Tallal [1997] for extensive discussion of issues of brain plasticity and language, and Merzenich et al. [1996] and Tallal et al. [1996] for initial findings on their procedures for treating language-learning-impaired children.) This appears to be one of the few cases in which basic neuroscience knowledge has led to an effective treatment for a learning disorder.*

*  

The conventional view of dyslexia is that the children have speech-specific deficits in phonological representation rather than in auditory temporal processing. This view finds considerable support in the literature. For example, Mody, Studdert-Kennedy, and Brady (1997) studied groups of second-grade children who were good and poor readers, matched for age and intelligence. The children were selected to differ on a temporal task used by Tallal as diagnostic (e.g., / ba / - / da / temporal order judgement task). The children were tested on several auditory tasks, including rapid changes in nonspeech sine wave analogues of speech sounds. The results supported the view that the perceptual problem for these poor readers was confusion between phonetically similar, though phonologically contrastive, syllables rather than difficulty in perceiving rapid auditory spectral changes, i.e., speech-specific rather than general auditory deficits. There are, of course, procedural differences between this and other studies supporting the phonological hypothesis and studies supporting the auditory perception hypothesis. Nonetheless, the work by Tallal and Merzenich offers a possible example of how basic research in neuroscience may have practical application to learning in a particular disadvantaged group.



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