On the notion of a "subtle phonetic deficit" in fluent/posterior aphasia.

Phonetic investigations in the past decade or so have reported instances of a "subtle phonetic deficit" in the fluent aphasias, thereby challenging the traditional dichotomy of a motoric deficit characterizing the nonfluent aphasias and a selection deficit characterizing the fluent aphasias. This paper critically reviews the acoustic, physiological, and perceptual studies which have attempted to examine this phenomenon. These investigations have been evaluated in terms of differences in subject populations, task demands, subjects' performance, and problematic interpretations. Suggestions are offered for an experimental design which can help us operationalize this term and help us to better understand the speech production deficit in fluent aphasic patients.