Levels of Processing in Sentence Comprehension : Evidence from Aphasic Syndromes and Damaged Hemispheres

Abstract

The purpose of the study was to assess comprehension capacities in brain-damaged aphasics. Eighteen aphasic patients following left hemisphere lesions (five Broca's, five Wernicke's, five anomic, and three conduction), three aphasic patients following right hemisphere lesions, and ten normal controls were given a sentence comprehension test. The task employed in this test was a sentence-picture matching task. The variables in the sentence material were activepassive formation, plausibility in sentence meaning, and word ordering in noun phrases. Conduction aphasics demonstrated the best test performance, followed by anomic, Broca's and Wernicke's, but there were no significant differences between Broca's and Wernicke's. Conduction aphasics made significantly fewer syntactic and semantic errors than each of the other groups. Broca's aphasics made significantly more syntactic errors than each of the other groups. Right-hemisphere damaged aphasics demonstrated the characteristic test performance. These results were relevant to the hypothesis that the linguistic impairment in Broca's aphasics was limited to a syntactic processing deficit.