Potential conflict of interest: Nothing to report.
Characteristics of the sequence effect in Parkinson's disease†
Version of Record online: 28 JUL 2010
Copyright © 2010 Movement Disorder Society
Volume 25, Issue 13, pages 2148–2155, 15 October 2010
How to Cite
Kang, S. Y., Wasaka, T., Shamim, E. A., Auh, S., Ueki, Y., Lopez, G. J., Kida, T., Jin, S.-H., Dang, N. and Hallett, M. (2010), Characteristics of the sequence effect in Parkinson's disease. Mov. Disord., 25: 2148–2155. doi: 10.1002/mds.23251
- Issue online: 28 JUL 2010
- Version of Record online: 28 JUL 2010
- Manuscript Accepted: 15 APR 2010
- Manuscript Revised: 12 FEB 2010
- Manuscript Received: 9 MAY 2009
- Parkinson's disease;
- sequence effect;
- pegboard test
The sequence effect (SE) in Parkinson's disease (PD) is progressive slowing of sequential movements. It is a feature of bradykinesia, but is separate from a general slowness without deterioration over time. It is commonly seen in PD, but its physiology is unclear. We measured general slowness and the SE separately with a computer-based, modified Purdue pegboard in 11 patients with advanced PD. We conducted a placebo-controlled, four-way crossover study to learn whether levodopa and repetitive transcranial magnetic stimulation (rTMS) could improve general slowness or the SE. We also examined the correlation between the SE and clinical fatigue. Levodopa alone and rTMS alone improved general slowness, but rTMS showed no additive effect on levodopa. Levodopa alone, rTMS alone, and their combination did not alleviate the SE. There was no correlation between the SE and fatigue. This study suggests that dopaminergic dysfunction and abnormal motor cortex excitability are not the relevant mechanisms for the SE. Additionally, the SE is not a component of clinical fatigue. Further work is needed to establish the physiology and clinical relevance of the SE. © 2010 Movement Disorder Society.