Temporal structure in the speech of persons with dementia: A preliminary study.

Abstract

Although cognitive and language processes in dementia have been studied extensively, the question of motor speech degeneration in the course of dementing illness is a relatively unexplored area. The potential for early dissociation of motor functions of language at the level of speech production has not been explored; an interaction between motor speech and language production and perception changes should inform our understanding of the deterioration in dementia. If early motor declines are found, they may provide an additional early marker and contribute to early detection, giving further insight to the character of neurological deterioration in this disease. This study explores the temporal structure of speech in individuals in the mild-to-moderate stages of the disease. In this preliminary study, participants were asked to produce a series of four-word phrases containing target word in phrase-medial or phrase final position. The target words contained the vowel in “heed,” “head,” or “had,” and began with a fricative or voiced or voiceless stop consonant and ended with either /t/ or /d/. Thus, we are able to examine four aspects of the temporal patterns of speech in these persons: intrinsic vowel duration, VOT, phrase-final lengthening, and the effect of final consonant voicing on vowel duration.