Abnormal regional CBF response in left hemisphere of dysphasic children during a language task.

This study used xenon 133 inhalation and single-photon computed tomography to measure regional cerebral blood flow during a quiet resting condition, a simple auditory task, and an auditory phonemic discrimination task in 3 age-matched groups of children suffering from developmental language disabilities: expressive dysphasia, expressive-receptive dysphasia, and attention-deficit hyperactivity disorder. An absence of left hemisphere activation was observed in the expressive-receptive group during the phonemic discrimination task as compared to both expressive and attention-deficit hyperactivity disorder children, together with an absence of left inferior parietal region activation in dysphasics as compared to hyperactive children. These results favor the hypothesis of an abnormal lateralization for language in dysphasic children and point toward possible different pathologic localizations in the different clinical subtypes of dysphasia.