The MRI appearance and neuropsychologic and speech/language evaluations in three patients with schizencephaly are described from the Department of Radiology, Michigan State University, East Lansing, MI. All patients presented with a seizure disorder and they were left-handed without familial sinistrality in first degree relatives. The primary areas of cerebral involvement were the left parasylvian and pararolandic regions with varying degrees of secondary involvement of the right hemisphere. There was mild right-sided limb hypoplasia, and motor dexterity with the dominant left hand was better than with the right hand. Two patients showed significant impairment in finger localization and tactile form recognition particularly with the nondominant right hand. The level of general intellectual functioning related to the amount of brain tissue involved, and neurobehavioral abilities reflected the location of the brain malformation and the prenatal onset of the disorder. The full scale IQ on the WAIS-R ranged from a low of 65 to a high of 87. Only one patient showed a higher verbal IQ than performance IQ and her visuospatial construction abilities and visual memory abilities were significantly impaired. There were varying degrees of linguistic deficit with relatively greater difficulties in syntactical speech than in semantic aspects. 
COMMENT. Yakovlev and Wadsworth first described the schizencephalies as congenital defects in the cerebral mantle in 1946. The patients in the present study shared features in common with the pathologic left handedness syndrome of Orsini and Satz; predominantly left-sided cerebral lesion with onset before six years of age and involving speech/language areas of frontotemporal parietal cortex, atypical or right-sided hemispheric speech representation, impaired visuospatial abilities and preserved verbal cognitive abilities, right limb hypoplasia, right hand motor impairment, and absence of familial sinistrality.