HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Mayston, M. J. Articles by Farmer, S. F. Search for Related Content PubMed PubMed Citation Articles by Mayston, M. J. Articles by Farmer, S. F.

Physiological tremor in human subjects with X-linked Kallmann's syndrome and mirror movements

M. J. Mayston, L. M. Harrison, J. A Stephens and S. F. Farmer *

1. Human physiological tremor consists of mechanical-reflex and neurogenic components. The origin of the neurogenic component, classically detected in the frequency range 7-12 Hz, has been much debated. We have studied six subjects with X-linked Kallmann's syndrome (XKS) and mirror movements. In these subjects unilateral magnetic brain stimulation results in abnormal bilateral EMG responses. Furthermore, abnormal sharing of central nervous inputs between the left and right motoneurone pools results in both abnormal motor unit synchronisation between left and right EMGs and abnormal sharing of long but not short-latency cutaneomuscular reflexes. XKS subjects with mirror movements thus provide a model for studying the central origin of physiological tremor.

2. During sustained co-extension of the left and right index fingers, simultaneous finger tremor and extensor indicis (EI) EMGs were recorded and cross-correlated. The tremor and EMG signals were also subjected to time and frequency domain analysis.

3. Results of frequency domain analysis between ipsilateral finger tremor and EI EMG were similar for both control and XKS subjects. However, in contrast to the controls, short-term synchronisation of left and right EI motor unit activity and significant coherence between left and right EMG, left and right tremor, left EMG and right tremor and right EMG and left tremor were found in XKS subjects. The frequency range (6-40 Hz) and coherence values between left and right were similar to ipsilateral coherence values of rectified EMG and tremor.

4. These data provide strong evidence to support the hypothesis that the neurogenic component of physiological tremor is supraspinal in origin and ranges from 6 to 40 Hz.

This article has been cited by other articles:

				S. F. Farmer, J. Gibbs, D. M. Halliday, L. M. Harrison, L. M. James, M. J. Mayston, and J. A. Stephens Changes in EMG coherence between long and short thumb abductor muscles during human development J. Physiol., March 1, 2007; 579(2): 389 - 402. [Abstract] [Full Text] [PDF]

				C. J. Mottram, E. A. Christou, F. G. Meyer, and R. M. Enoka Frequency Modulation of Motor Unit Discharge Has Task-Dependent Effects on Fluctuations in Motor Output J Neurophysiol, October 1, 2005; 94(4): 2878 - 2887. [Abstract] [Full Text] [PDF]

				C. T. Moritz, E. A. Christou, F. G. Meyer, and R. M. Enoka Coherence at 16-32 Hz Can Be Caused by Short-Term Synchrony of Motor Units J Neurophysiol, July 1, 2005; 94(1): 105 - 118. [Abstract] [Full Text] [PDF]

				S. F. Farmer, L. M. Harrison, M. J. Mayston, A. Parekh, L.M. James, and J. A. Stephens Abnormal cortex-muscle interactions in subjects with X-linked Kallmann's syndrome and mirror movements Brain, February 1, 2004; 127(2): 385 - 397. [Abstract] [Full Text] [PDF]