Evidence that ventrolateral thalamotomy may eliminate the supraspinal component of both pathological and physiological tremors

Abstract.

Ventrolateral (VL) thalamotomy produced a marked reduction of oscillations related to the supraspinal components of Parkinson's disease tremor (4–7 Hz) and physiological tremor (8–12 Hz). Finger tremor was examined in nine patients undergoing unilateral VL thalamotomy and in nine age-matched controls. In comparison to the preoperative state, the relative percentage of power within the 7.6–12.5 Hz band did not increase after the surgical procedure. Furthermore, the amount of absolute power within the 7.6–12.5 Hz band was much lower for post-surgical patients in comparison to matched controls when periods of tremor having equal amplitudes were compared. These results suggest that VL thalamotomy interrupts a common circuit involved in the supraspinal component of both physiological and pathological tremors. We provide evidence that the thalamus may be involved in circuits generating physiological tremor in humans.