Effects of topical anesthesia on essential tremor.

In a single-blinded study, the effects of skin desensitization by topical anesthesia (4% xylocaine) on six patients who had essential tremor were investigated. Resting hand tremor was monitored using an accelerometer and multiple surface electromyograms. The amplitude and frequency characteristics of the oscillations were determined using spectral analysis. Topical anesthesia significantly suppressed the tremor amplitude and the associated electrical activity in all patients: the mean tremor amplitude was reduced by 40%. No changes in the frequencies of the essential tremors were detected.