Biofeedback Specialization Effect on Physiological Tremor Amplitude Dynamics

Abstract

Physiological tremor amplitude was studied along with the possibility of its biofeedback guided modification. Physiological tremor was recorded using three-axial digital accelerometers fixed on the external side of the index fingers. Subjects were asked to perform a series of 15-s physiological tremor tests with breaks to rest. Four biofeedback modes were used to minimize the following control parameters: hand inclination from a horizontal plane, mean tremor amplitude over both hands, tremor amplitude of the right hand with simulated left hand one, and inverse combination. The tremor amplitudes obtained in biofeedback conditions were compared to normal values, which were recorded before and after biofeedback testing. The possibility of targeted physiological tremor modification in a 8–12 Hz frequency band was proved by the suppression of tremor amplitude in biofeedback conditions. A transition of the tremor suppression effect in the band 8–12 Hz was observed; i.e., the tremor amplitude from the dominant arm significantly decreased when biofeedback parameters were obtained from the contralateral arm.