Diurnal variability of orofacial dyskinetic movements

Objective: Instrumental methods to measure tardive dyskinesia (TD) have bee n introduced in the last few years to try to eliminate the differences in i nter-rater reliability. After eliminating variations attributed to the use of different raters, it is clear that TD frequently shows fluctuations in s everity contributing to a low test-retest reliability. In the present study the diurnal variability of dyskinetic movements was explored by a computer ized technique using digital imaging processing to measure orofacial moveme nts. Method: Ten patients with persistent tardive dyskinesia were assessed three times a day once a week for four consecutive weeks. Results: Four pat ients had significant diurnal variations in the severity of dyskinetic move ments and six did not have significant variations. The period of time betwe en waking and the assessment, the severity of dyskinetic movements, and smo king were significantly different between these two groups. Conclusion: Diu rnal variations, particularly in relation to sleeping and smelting patterns , may need to be taken into account during longitudinal studies of tardive dyskinesia.