Perceptual and acoustic studies of Parkinson's disease patients' productions of place contrasts in CV syllables were extended from isolated productions of /ba/, /da/ and /ga/ to continuous productions of /pa/, /ta/ and /ka/ to determine whether greater difficulties occur in continuous speech. Intelligibility scores of listeners on a forced choice identification task demonstrated normal intelligibility. Acoustic measures of first and second formants, rate of change and voice onset time also resulted in very few differences from normal. This indicated that these patients have few errors in stop consonants place of articulation contrasts in controlled speech testing. These laboratory results are not commensurate with clinical impressions of poor speech intelligibility of patients during conversation. Two new types of studies have been initiated this year. In one, perceptual and acoustic measures will be made of stops and fricatives in CV and VC syllables embedded in extended speech phrases. In the other, the effects of word frequency, word length and speech planning on measures of speech initiation time, movement velocity and inter-articulator coordination are being studied in normal adults and Parkinson's disease patients. A pilot study of lip and jaw movement velocity and displacement in patients with tardive dyskinesia examined movement during voluntary speech tasks. The same maximum displacement points were reached but at lower velocities suggesting that voluntary movement is affected by this disorder.
