Task force report on scales to assess dyskinesia in Parkinson's disease: critique and recommendations.

Drug-induced dyskinesia is a common phenomenon in Parkinson's disease (PD) and is often socially as well as physically disabling for patients. The Movement Disorders Society commissioned a task force to assess available clinical rating scales, critique their clinimetric properties, and make recommendations regarding their clinical utility. A task force composed six clinical researchers who systematically searched the literature for scales measuring dyskinesia in PD, evaluated the scales' previous use, performance parameters, and quality of validation data (if available). A scale was designated "Recommended" if the scale has been used in clinical studies beyond the group that developed it, has been specifically used in PD reports, and if clinimetric studies have established that it is a valid, reliable, and sensitive. "Suggested" scales met two of the above criteria and those meeting one were "Listed." Based on the systematic review, eight rating scales for dyskinesia that have either been validated or used in PD were identified. These were the Abnormal Involuntary Movement Scale (AIMS), The Unified Parkinson's Disease Rating Scale (UPDRS) part IV, the Obeso Dyskinesia Rating Scale, the Rush Dyskinesia Rating Scale, the Clinical Dyskinesia Rating Scale (CDRS), the Lang-Fahn Activities of Daily Living Dyskinesia Scale, the Parkinson Disease Dyskinesia Scale (PDYS-26), and the Unified Dyskinesia Rating Scale (UDysRS). Based on this review, at present two of the reviewed dyskinesia scales (AIMS and the Rush Dyskinesia Rating Scale) fulfill criteria for Recommended for use in PD populations, albeit weakly so; all of the remaining met criteria to be Suggested. However, the two most recent scales (PDYS-26 and UDysRS) have excellent clinimetric properties and appear to provide a reliable and valid assessment tool of dyskinesia in PD. If they are used successfully beyond the groups that developed them, both have the potential to be re-ranked as Recommended. As further testing of these scales in PD is warranted, no new scales are needed until the available scales are fully tested clinimetrically.