A 3 C/sec leg tremor in a "cerebellar" syndrome.

A unique leg tremor was found in patients with late (acquired) cerebellar atrophy. Such patients are classically said to show a cerebellar incoordination in the heel-knee test. The tremor was evoked in three sustained leg postures inducing single plane oscillations. In these tests the tremor occurred as leg extensions, adductions or torsions. Accelerometer records showed a simple 2.5-3.5 c/sec rhythm. The amplitude varied but the rate was remarkably constant. The heel-on-knee position elicited tremor activity in muscles working in various planes; the resulting compound oscillation could be confused with irregular goal-seaking movements.