A simple and portable ultrasound system, using a transducer attached to a pair of spectacles, to measure disorders of facial movement is described and applied to the measurement of tardive dyskinesia. Product-moment coefficients of correlation for the split-half and test-retest assessments of reliability in 20 patients were 0.96 and 0.93 respectively. Concurrent validity was confirmed by assessing the consistency between ultrasound scores and time-sampled scores based on video films (Pearson r = 0.86). Serial measurements of tardive dyskinesia over five months revealed striking individual consistency.

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