A comparison of changes in macrolinguistic and microlinguistic aspects of discourse production in normal aging.

Middle-aged and elderly healthy subjects were interviewed informally, and their discourse productions were analyzed to test for age-related changes in language-specific, microlinguistic, and in higher order organizational, macrolinguistic abilities. No significant age differences were found on microlinguistic measures, including syntactic complexity and syntactic and lexical production errors, and there were also no age differences in the use of lexical cohesive ties, such as anaphora. Older subjects, however, obtained significantly lower ratings on a macrolinguistic measure of global thematic coherence. Elderly subjects failed to maintain coherent reference to the general topic of discourse, although they preserved coherent meaning relationships between contiguous utterances. These results are most compatible with the view that age-related performance declines on language tasks primarily reflect changes in macrolinguistic abilities that require integration of linguistic and nonlinguistic cognitive processes, rather than changes in language-specific cognitive processes.