Performance of subjects with multiple sclerosis on tests of high-level language

The present study describes the high-level language (HLL) abilities of a group of 60 subjects with multiple sclerosis (MS) based on their performance on the Test of Language Competence (TLC) and The Word Test (TWT). Comparative performance of the MS group with matched control subjects revealed that the MS subjects presented with difficulties understanding ambiguous sentences and metaphoric expressions, making inferences, and re-creating sentences, and exhibited relatively poor performance on vocabulary and semantic tasks. Subjects with both a chronic progressive (CP) (n = 32) and relapsing remitting (RR) (n = 28) course of MS had significant HLL problems, thereby suggesting that the presence of language deficits is not determined by disease course, as proposed by some authors. However, it was noted that the CP group had more severe language problems than the RR group, as indicated by lower scores on tasks requiring the subjects to re-create sentences, understand ambiguous sentences, make associations, identify synonyms and define words. The implications of the findings of HLL deficits in both CP and RR forms of MS are discussed in relation to the role of subcortical white matter pathways in language processing.