1531-8257/asset/MDS_left.gif?v=1&s=a99f3b698e6ae32e96dbc75c912d289e5c35649d)
1531-8257/asset/MDS_right.gif?v=1&s=4d3c8316b533aa4e41b7101a2d6fa6f082cf2505)
Article
Factors influencing the amplitude and frequency of essential tremor
Article first published online: 12 OCT 2004
DOI: 10.1002/mds.870090602
Copyright © 1994 Movement Disorder Society
1531-8257/asset/cover.gif?v=1&s=cbca75ec4eec6abb5c8560896c83f19bae8de2b1 "Movement Disorders")
Additional Information
How to Cite
Elble, R. J., Higgins, C., Leffler, K. and Hughes, L. (1994), Factors influencing the amplitude and frequency of essential tremor. Mov. Disord., 9: 589–596. doi: 10.1002/mds.870090602
Publication History
- Issue published online: 12 OCT 2004
- Article first published online: 12 OCT 2004
- Abstract
- References
- Cited By
Keywords:
- Tremor;
- Aging;
- Electromyography;
- Motor control
Abstract
Quantitative electromyography (EMG) and triaxial accelerometry were used to measure hand tremor, finger tremor, and forearm motor unit activity in 36 men and 23 women with essential tremor. Hand tremor was studied with and without 300-g mass loading. Tremor and EMG were recorded twice, with a 3-min rest interval, to assess the spontaneous intertrial variability in tremor amplitude, frequency, and motor unit entrainment. In general, the minimum detectable differences in tremor amplitude, frequency, and motor unit entrainment were roughly 30%, 5%, and 10% of the initial sample means, respectively, assuming a sample size of 30 patients, a statistical power of 0.9, and a significance level of 0.05. Linear regression analyses were performed to test the hypotheses that (a) there is an age-associated decrease in tremor frequency that is independent of symptom duration and (b) tremor frequency and motor unit entrainment make independent contributions to tremor amplitude. Our data supported both hypotheses.