LANGUAGE-LEARNING IMPAIRMENTS - INTEGRATING BASIC SCIENCE, TECHNOLOGY, AND REMEDIATION

One of the fundamental goals of the modern field of neuroscience is to understand how neuronal activity gives rise to higher cortical functi on. However, to bridge the Sap between neurobiology and behavior, we m ust understand higher cortical functions at the behavioral level at le ast as well as we have come to understand neurobiological processes at the cellular and molecular levels. This is certainly the case in the study of speech processing, where critical studies of behavioral dysfu nction have provided key insights into the basic neurobiological mecha nisms relevant to speech perception and production. Much of this progr ess derives from a detailed analysis of the sensory, perceptual, cogni tive, and motor abilities of children who fail to acquire speech, lang uage, and reading skills normally within the context of otherwise norm al development. Current research now shows that a dysfunction in norma l phonological processing, which is critical to the development of ora l and written language, may derive, at least in part, from difficultie s in perceiving and producing basic sensory-motor information in rapid succession - within tens of ms (see Tallal et al. 1993a for a review) . There is now substantial evidence supporting the hypothesis that bas ic temporal integration processes play a fundamental role in establish ing neural representations for the units of speech (phonemes), which m ust be segmented from the (continuous) speech stream and combined to f orm words, in order for the normal development of oral and written lan guage to proceed. Results from magnetic resonance imaging (MRI) and po sitron emission tomography (PET) studies, as well as studies of behavi oral performance in normal and language impaired children and adults, will be reviewed to support the view that the integration of rapidly c hanging successive acoustic events plays a primary role in phonologica l development and disorders. Finally, remediation studies based on thi s research, coupled with neuroplasticity research, will he presented.