TY - JOUR A2 - Louis, E. D. AU - Vassar, Stefanie D. AU - Bordelon, Yvette M. AU - Hays, Ron D. AU - Diaz, Natalie AU - Rausch, Rebecca AU - Mao, Cherry AU - Vickrey, Barbara G. PY - 2012 DA - 2012/10/22 TI - Confirmatory Factor Analysis of the Motor Unified Parkinson’s Disease Rating Scale SP - 719167 VL - 2012 AB - The motor examination section of the unified Parkinson’s disease rating scale (UPDRS) is widely used in research but few studies have examined whether subscales exist that tap relatively distinct motor abnormalities. We analyzed data from 193 persons enrolled in a population-based study in Central California. Patients were examined after overnight PD medication washout (“OFF” state) and approximately one hour after taking medication (“ON” state). We performed confirmatory factor analysis of the UPDRS for OFF and ON state examinations; correlations, reliability, and relative validity of resulting subscales were evaluated. A model with five factors (gait/posture, tremor, rigidity, bradykinesia affecting the left extremities, bradykinesia affecting the right extremities) fit the data well, with similar results for OFF and ON states. Internal consistency reliability coefficients were 0.90 or higher for all subscales. The gait/posture subscale most strongly discriminated across levels of patient reported PD symptom severity and of how PD affects them on a daily basis. Compared to the right sided bradykinesia subscale, the left sided bradykinesia subscale had higher discrimination across levels of self-reported PD symptom severity and functional impairment. This supports motor UPDRS containing multiple subscales that can be analyzed separately and provide information distinct from the total score that may be useful in clinical studies. SN - 2090-8083 UR - https://doi.org/10.1155/2012/719167 DO - 10.1155/2012/719167 JF - Parkinson’s Disease PB - Hindawi Publishing Corporation KW - ER -