Selective Preservation of Syntax in Alzheimer's Dementia.

A study investigating the independence of linguistic abilities from each other, specifically the separability of syntax and semantics and the autonomy of syntactic abilities, is described. In the study, 30 individuals with Alzheimer's disease produced spontaneous conversations, completed sentences eliciting 16 grammatical forms, and when possible, wrote homophones dictated to them. Results showed consistently intact syntactic ability alongside marked deficits in semantic abilities across the three distinct task types. In addition, where it was possible to gauge pragmatic skills, it was found that certain conversational skills such as turn-taking and use of social interaction formulas remained intact while others such as topic maintenance showed significant impairment. This is consistent with research on aphasia showing behavioral and neuropsychological independence of language components. It is concluded that syntactic processes are an autonomous neuropsychological ability separate from lexical functioning in language production. Further research is under way on the preservation of syntax and semantics. (MSE)