Impressions of parkinsonian patients from their recorded voices

The voices of patients suffering from Parkinson's disease change in various ways. This paper sets out to examine the effect of these changes on the impressions made on listeners, and to try to see what vocalic and prosodic features account for these impressions. Tape recordings from segments of interviews with 4 patients, and 4 control subjects with ischaemic heart disease, were played to 16 naive listeners. These listeners were asked to rate their impressions of these voices on 15 dimensions of personality. There were significant differences on most of the dimensions, despite the fact that there were no differences between the two groups on such scales as Beck's depression inventory and the mood adjective check list. The parkinsonian patients were seen to be cold, withdrawn and anxious, not to relate well to the interviewer and to be enjoying the interview less than the controls. These ratings are very similar to those previously reported for the same patients, using silent video recordings only. The voice recordings were analysed along various dimensions of prosody. The factors which were different between the groups included the frequency and type of pauses in speech and the range or variability of the fundamental frequency. The implications of this exploratory study for intervention are discussed.