Absence of enhanced physiological tremor in patients without muscle or cutaneous afferents.

Patients with proprioceptive loss due to a neuropathy affecting large myelinated sensory nerve fibres were studied to determine the role of somaesthetic sensory inputs in enhanced physiological tremor. Involuntary movements in patients and controls attempting to hold the outstretched arm immobile were recorded during prolonged arm extension. Fatigue led to increased movements in both controls and patients but only the controls developed a rhythmic tremor. These data indicate that enhanced physiological tremor is dependent on somaesthetic afferent input.