Cerebral lateralization in linguistic and nonlinguistic perception: analysis of cognitive styles in the auditory...

Twenty-two normal subjects (9 left-handers, 13 right-handers) and five dyslexic patients (3 right-handers, and 2 left-handers) were characterized by physiologic hemisphere dominance. The latter was determined by the response of the middle cerebral artery (MCA) blood flow velocity, measured using the transcranial Doppler (TCD) technique, to hypoventilation (hypercapnia). Using bilateral almost simultaneous TCD measurements of mean blood flow velocity in the MCA, lateralization was determined in response to linguistic and nonlinguistic paradigms. In relation to the linguistic paradigm, left-handers, showed lateralization to the physiologic nondominant hemisphere, while right-handers showed lateralization to the physiologic dominant hemisphere; dyslexic patients show trends opposite to those in normals.