ABSTRACT
The evidence reviewed so far indicates that disorders of nonverbal conceptual thinking were more severe and more frequent in aphasies, as a group, than in left and right nonaphasic braindamaged patients and controls. The hypothesis that nonverbal conceptual disorders are specifically linked to semantic-lexical impairment is both attractive and rather convincing to clinicians who are familiar with aphasia. A functional relationship may be inferred whenever both nonverbal and verbal performances of aphasies display a basic similarity in the quality of the deviant behaviour. Aphasies who perform quite poorly on nonverbal tests of conceptual thinking often display virtually normal judgement and categorising ability in dealing with real-life situations. Aphasies, while specifically failing on the first test, were unimpaired on the second, which, by contrast, was particularly vulnerable to lesions of the right hemisphere. The evidence to date suggests that some kind of functional relationship does exist between aphasia and the concomitant non verbal conceptual impairment.
