Effects of vision and arm position on amplitude of arm postural tremor in patients with multiple sclerosis.

Abstract

To quantify the effects of vision and arm position on arm postural tremor, comparisons were made between flexed and extended arm positions performed with the eyes open and closed. Case-control study. National multiple sclerosis (MS) center in Belgium. Sixteen patients (32 arms) with MS who had intention tremor and 16 healthy controls (32 arms). Not applicable. The amplitude of postural tremor was assessed by a magnetic position sensor attached to the index finger. The amplitude of postural tremor was not influenced by changes in visual condition or different arm positions. Both healthy controls and MS patients made more directional changes in the flexed, compared with the extended arm position. The amplitude of the arm postural tremor in MS is independent of vision and arm position. Selecting 1 arm position is sufficient to assess postural tremor amplitude.