Abstract

Essential tremor is the most common form of pathologic tremor, but little is known about its underlying pathophysiology. Many investigators have speculated that essential tremor emerges from pathological change in the mechanisms of physiologic tremor, but until recently, there was little support for this hypothesis. Mild essential tremor is qualitatively identical to the 8- to 12-Hz component of physiologic tremor. More advanced essential tremor exhibits a frequency of 4 to 7 Hz. Consequently, a negative logarithmic relationship exists between the amplitude and frequency of essential tremor. Based upon these observations, the progression of essential tremor probably entails a gradual reduction in its frequency. A pilot study of 18 patients supported this hypothesis, which will now be tested in a larger cohort of patients. Wrist tremor and forearm electromyograms (EMG), writing tremor and head tremor will be recorded from 100 patients in years 1, 3 and 5 of this grant. The majority of these patients will come from one or more generations of 51 families with essential tremor. Tremor amplitude and frequency will be computed by spectral analysis, and the changes in tremor amplitude and frequency, over time, will be determined. Wrist tremor and forearm EMG will also be recorded from 100 20- to 40-year-old male and female controls. Two groups of controls will be identified: those with and those without a prominent 8- to 12-Hz tremor. The prevalence of a parent with essential tremor in the two groups will be compared. In addition, the prevalence of a prominent 8- to 12-Hz tremor in this cohort of 100 controls will be compared with that in a comparable number of the patients' siblings. These studies will provide important insight into the clinical significance of a prominent 8- to of this tremor to essential tremor. Finally, the essential tremor oscillator will continue to be of essential tremor to sinusoidal and pulsatile a computer-controlled torque motor and provide further insight into the role of the in governing the clinical expression of the, as yet unidentified, neural oscillator of essential tremor.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS020973-09
Application #
2264011
Study Section
Neurology A Study Section (NEUA)
Project Start
1984-07-01
Project End
1996-11-30
Budget Start
1993-12-01
Budget End
1994-11-30
Support Year
9
Fiscal Year
1994
Total Cost
Indirect Cost

  Institution

Name
Southern Illinois University School of Medicine
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
City
Springfield
State
IL
Country
United States
Zip Code
62794

  Publications

Elble, Rodger J; Pullman, Seth L; Matsumoto, Joseph Y et al. (2006) Tremor amplitude is logarithmically related to 4- and 5-point tremor rating scales. Brain 129:2660-6
Elble, Rodger J; Higgins, Connie; Elble, Suzanne (2005) Electrophysiologic transition from physiologic tremor to essential tremor. Mov Disord 20:1038-42
Elble, Rodger J (2003) Characteristics of physiologic tremor in young and elderly adults. Clin Neurophysiol 114:624-35
Elble, R J (2000) Diagnostic criteria for essential tremor and differential diagnosis. Neurology 54:S2-6
Elble, R J (1998) Animal models of action tremor. Mov Disord 13 Suppl 3:35-9
Elble, R J (1998) Tremor in ostensibly normal elderly people. Mov Disord 13:457-64
Elble, R J; Brilliant, M; Leffler, K et al. (1996) Quantification of essential tremor in writing and drawing. Mov Disord 11:70-8
Qureshi, F; Morales, A; Elble, R J (1996) Tremor due to infarction in the ventrolateral thalamus. Mov Disord 11:440-4
Elble, R J (1996) Central mechanisms of tremor. J Clin Neurophysiol 13:133-44
Elble, R J (1995) The role of aging in the clinical expression of essential tremor. Exp Gerontol 30:337-47

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