ABSTRACTThe first impressions formed by 19 senior speech therapy students shown silent video recordings of four patients with idiopathic Parkinson's disease (PD) and four with ischaemic heart disease were measured using visual analogue scales directed at aspects of mood, personality and intellect. Although both patient groups showed no abnormalities in terms of affect, personality and intelligence by standardised psychological tests, the PD patients appeared more anxious, hostile, suspicious, depressed, bored and tense than the controls; they seemd less intelligent, more introverted and passive and looked as if they enjoyed and maintained their part of the conversation less well. They appeared to relate less well to the interviewer although there was no apparent difference in the interviewer's behaviour to the two different disease groups. Overall they were rated as less likeable. The speech therapists' responses did not differ significantly from a previous study of other health professionals. The findings are related to the known effects of speech impairment on impression formation in Parkinson's disease and are discussed in relation to possible effects on therapeutic relationships and management of patients with impaired expressive behaviour.