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© 2003 American Academy of Neurology Deep brain stimulation of the VIM thalamic nucleus modifies several features of essential tremorFrom the School of Kinesiology (Drs. Vaillancourt and Corcos, and M.M. Sturman), Department of Bioengineering (Dr. Corcos), and Department of Physical Therapy (Dr. Corcos), University of Illinois at Chicago; and Departments of Neurological Sciences (Drs. Verhagen Metman, Bakay, and Corcos) and Neurosurgery (Drs. Verhagen Metman and Bakay), Rush Presbyterian–St. Luke’s Medical Center, Chicago, IL. Address correspondence and reprint requests to Dr. David E. Vaillancourt, School of Kinesiology (M/C 194), University of Illinois at Chicago, 901 West Roosevelt Road, Chicago, IL 60608; e-mail: court1{at}uic.edu Background: Pharmacologic interventions (e.g., ß blockers) and thalamic lesions have failed to alter the pathophysiology of essential tremor (ET) beyond a reduction in tremor amplitude. Deep brain stimulation (DBS) of the ventral intermediate (VIM) nucleus of the thalamus successfully reduces tremor rating scores. It is unknown how VIM DBS alters the pathophysiologic characteristics of ET. Objective: To determine the effects of VIM DBS on the neurophysiologic characteristics of ET. Methods: Hand tremor and EMG activity of forearm extensor and flexor muscles were recorded in six patients with ET ON-DBS and OFF-DBS and from six age- and sex-matched control subjects. Hand tremor was assessed across different inertial loads. The amplitude, frequency, regularity, and tremor–EMG coherence were analyzed. Results: VIM DBS reduced the amplitude, increased the frequency, decreased the regularity, and reduced the 1 to 8 Hz tremor–EMG coherence of ET. ON-DBS, patients with ET had greater tremor amplitude, lower frequency, more regularity, and greater tremor–EMG coherence compared to control subjects. Conclusions: Whereas pharmacologic and thalamic lesions have previously failed to change characteristics of ET beyond amplitude reduction, VIM DBS modified multiple features of ET. The changes in ET after VIM DBS provide strong evidence for clinical efficacy.
Received January 13, 2003. Accepted in final form June 16, 2003. This article has been cited by other articles:
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