[Spectral electromyographic analysis of essential tremor].

The authors have developed a new method of computerized statistical analysis of the spectral parameters of the circumscribing electromyogram in patients with essential tremor (ET), making use of objective frequency and amplitude parameters. The results have shown that ET differed from physiological tremor not only by amplitude but also by frequency characteristics. Four groups of patients have been identified which differed in relation to both parameters. Clear-cut criteria have been defined which may be used in the differential diagnosis between ET and parkinsonism-associated tremor. It has been suggested that the pathological mechanisms of ET and parkinsonism-associated tremor differ in their location.