A review of the assessment of dyskinesias.

Dyskinesias are most prevalent in patients with Huntington's disease (HD), patients with Parkinson's disease (PD) who have received chronic levodopa therapy, and in patients who have been treated with neuroleptics (tardive dyskinesia ITD]). Recent therapeutic developments have fueled a growing interest in the clinimetrics of dyskinesias. For dyskinesias in HD, few rating scales are available, but data on validity, reliability, and responsiveness are scarce. Only the interrater reliability of facial dyskinesias has been evaluated and found to be low. Many subjective rating scales for dyskinesias in PD exist, but only the Dyskinesia Rating Scale has undergone sufficient clinimetric evaluation. For TD, numerous rating scales are available, many of them with ample data on reliability and validity. Objective assessment of dyskinesias has been attempted with a number of techniques. All these methods require a laboratory setting, rendering them susceptible to influence of stress. Moreover, they provide only a momentary assessment of dyskinesia severity and fail to take into account diurnal fluctuations. In view of the methodologic shortcomings in the assessment of dyskinesias, more effort needs to be put into strengthening currently available modes of assessment or designing new ones. In the future ambulatory accelerometry might prove to be of value in this field.