Persistent deficits in complex language function following dominant nonthalamic subcortical lesions

The language abilities of 14 subjects with chronic nonthalamic subcortical (NS) lesions following stroke was assessed using a test battery probing a broad range of language functions. The language battery included the Boston Naming Test (BNT), the Western Aphasia Battery (WAB), and subtests from the Test of language Competence-Expanded Edition, the Test of Word Knowledge, and The Word Test-Revised. The performance of the subjects with NS lesions did not differ significantly from a group of matched non-neurologically impaired subjects on most aspects of the WAB, whereas subjects with NS lesions evidenced deficits on the BNT and in word-list generation, recreating sentences, interpreting ambiguous or figurative passages, and in providing definitions, synonyms, and antonyms. These results suggest that standard aphasia batteries may be largely insensitive to subtle deficits in more cognitively demanding aspects of language function which can occur following NS lesions. The implications of these findings are considered in terms of current theories of subcortical language function.