POLYGRAPHIC ANALYSIS OF TREMOR - THE IMPA CT OF DISPARITIES OF TREMORFREQUENCIES FOR THE PATHOPHYSIOLOGY AND DIFFERENTIAL-DIAGNOSIS OF TREMOR

Tremor was electromyographically recorded simultaneously from up to 5 limb muscles in a total of 58 patients (28 patients with Parkinson's d isease, 11 with cerebellar tremor, 10 with essential tremor, 5 with ps ychogenic tremor, 4 with enhanced physiological tremor). Identical tre mor frequencies (Delta Hz less than 0,2) in antagonistic pairs of musc les were found in 51 of 56 patients, in proximum versus distant muscle s of one limb in 36 of 48 patients, in bilateral arm or leg muscles on both sides in 3 of 26 patients and in arm and leg muscles on either s ide in 1 of 11 patients with organic tremors. Three patients with psyc hogenic tremor had identical tremor frequencies in homonymous muscles on both sides. These results suggest that the incidence of tremor freq uency disparities increases with the degree of functional independence of the trembling muscles in organic tremors. There was no obvious ass ociation between the tremor frequency and the reflex path length. Thes e findings point to a somatotopical organization of the tremor generat ing structures.