Abstract
In this study we evaluated a technique for tremor suppression with functional electrical stimulation (FES), the technical details of which were described in the previous paper. Three groups of patients were investigated: those with essential tremor, parkinsonian tremor, and cerebellar tremor associated with multiple sclerosis. In each group, tremor was attenuated by significant amounts (essential tremor: 73%; parkinsonian tremor: 62%; cerebellar tremor: 38%). These attenuations were in good accord with predictions based on the dynamic analyses and filter designs derived in the previous paper. With filters “tuned” to the lower mean tremor frequency encountered in the cerebellar patients, more attenuation was possible in this group as well. We identified some practical limitations in the clinical application of the technique in its present form. The most important was that in daily use, only one antagonist pair of muscles can realistically be controlled. At first sight, this restricts the usefulness of the system to patients with single-joint tremors. However, the concomitant use of mechanical orthoses may broaden the scope of application.
Similar content being viewed by others
References
Freund, H.-J.; Hefter, H.; Homberg, V.; Reiners, K. Determinants of tremor rate. In: Findley, L.J.; Capildeo, R., eds. Movement disorders: Tremor. London: Macmillan; 1984: pp. 195–204.
Hewer, L.R.; Cooper, R.; Morgan, M.H. An investigation into the value of treating intention tremor by weighting the affected limb. Brain 95:579–590; 1972.
Javidan, M.; Elek, J.; Prochazka, A. Tremor reduction by functional electrical stimulation. Neurology 40:369; 1990.
Lee, R.G.; Stein, R.B. Resetting of tremor by mechanical perturbations: A comparison of essential tremor and Parkinsonian tremor. Ann. Neurol. 10:523–531; 1981.
Marsden, C.D. Origins of normal and pathological tremor. In: Findley, L.J.; Capildeo, R., eds. Movement disorders: Tremor. London: Macmillan; 1984: pp. 37–84.
Morrice, B.L.; Lee, R.G.; Becker, W.J.; White, D.G.; Hoffer, J.A. Viscous loading improves manual tracking accuracy in humans with cerebellar incoordination. Soc. Neurosci. Abstracts 13:1700; 1987.
Prochazka, A.; Elek, J.; Javidan, M. Attenuation of pathological tremors by functional electrical stimulation I: Method. Ann. Biomed. Eng. 20:205–224; 1992.
Prochazka, A.; Davis, L.; Gauthier, M. New intramuscular electrodes and microprocessor control of electrical stimulation to improve hemiparetic gait. Soc. Neurosci. Abstracts. 17:1468; 1991.
Rack, P.M.H.; Ross, H.F. The role of reflexes in the resting tremor of Parkinson's Disease. Brain 109:115–141; 1986.
Stein, R.B.; Prochazka, A.; Popovic, D.; Edamura, M.; Llewellyn, M.; Davis, L.A. Technology transfer and development for walking using functional electrical stimulation. In: D. Popovic, ed. Advances in external control of human extremities X. Belgrade: Yugoslav Committee for Electronics and Automation; 1990: pp. 161–176.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Javidan, M., Elek, J. & Prochazka, A. Attenuation of pathological tremors by functional electrical stimulation II: Clinical evaluation. Ann Biomed Eng 20, 225–236 (1992). https://doi.org/10.1007/BF02368522
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF02368522