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Parkinson’s Disease
Volume 2011 (2011), Article ID 967839, 6 pages
Clinical Study

Medication Responsiveness of Motor Symptoms in a Population-Based Study of Parkinson Disease

1Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095-7334, USA
2Department of Medicine, UCLA Division of General Internal Medicine and Health Services Research, Los Angeles, CA 90095-1736, USA
3UCLA School of Public Health, Los Angeles, CA 90095-1772, USA
4RAND, Santa Monica, CA 90407-2138, USA
5Parkinson's Disease Research, VA Greater Los Angeles Healthcare System, Education and Clinical Center, Los Angeles, CA 90073, USA
6Department of Neurology, Harbor-UCLA Medical Center, Torrance, CA 90502, USA

Received 16 August 2011; Revised 4 October 2011; Accepted 5 October 2011

Academic Editor: Jan O. Aasly

Copyright © 2011 Yvette M. Bordelon et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


We assessed degree of Parkinson disease motor symptom improvement with medication among subjects enrolled in an ongoing, population-based study in Central California. The motor section of the unified Parkinson disease rating scale (UPDRS) was performed on subjects in both OFF and ON medication states, and difference between these scores was used as an indicator of symptomatic benefit. Higher OFF minus ON scores correlated with more severe baseline symptoms. There was equivalent improvement on the motor UPDRS scale for subjects divided according to medication classes used: levodopa alone 7.3 points, levodopa plus other medications 8.5 points, and dopamine agonists but not levodopa 6.1 points. In addition, there was no difference in the magnitude of improvement when subjects were divided according to Parkinson disease subtype, defined as tremor dominant, akinetic-rigid, or mixed. In this community-based sample, these values are within the range of a clinically important difference as defined by previous studies.