Verbal processing by the brain.

Reitan and Wolfson (1985) have proposed a model of brain-behavior relationships which postulates a three-part organization of higher-level aspects of central processing: Verbal and related language functions (mainly left hemisphere), visual-spatial and related abilities (mainly right hemisphere), and conceptual abilities (both hemispheres). Three groups of subjects (controls, left cerebral lesions, and right cerebral lesions) and two strictly verbal tests (the Word Finding Test and the Vocabulary subtest from the Wechsler Scale) were used as a partial test of this model. Left cerebral lesions impaired Vocabulary scores but right cerebral lesions had little if any impairing effect. However, on the Word Finding Test, which has a strong conceptual requirement in addition to the verbal requirement, the group with left cerebral lesions continued to show striking impairment but the group with right cerebral lesions also showed significant impairment as compared to the control group. Additional studies are needed to test the proposed model in more detail.