ABSTRACT
Infantile autism is a behavioral syndrome consisting of specific disturbances of social relating and communication, language, response to objects, sensory modulation, and motility. The uniqueness of behavioural syndrome suggests one underlying pathophysiologic mechanism, although multiple etiologies, which could activate or replicate such a mechanism, have been demonstrated. Neurophysiologic hypotheses of infantile autism fall into two broad categories. One is a caudally directed sequence of pathophysiologic influence originating in telencephalic structures. The other is a rostrally directed sequence of pathophysiologic influence originating in brainstem and diencephalic structures. The telencephalic hypothesis of autism has stimulated investigations of hemispheric lateralization and other cortical phenomena. The chapter explores each hypothesis to relevant aspects of autistic behavior, reviews neurophysiologic research relevant to each hypothesis, and describes completed studies of vestibular nystagmus, relating these new findings to the brainstem-diencephalic hypothesis. It suggests that some possible complementary effects of the pathophysiologic mechanisms proposed in each of the neurophysiologic hypotheses.
