The effects of stochastic resonance stimulation on spine proprioception and postural control in chronic low back pain patients.

Abstract

Spine proprioception and postural control in unstable sitting were compared in 18 chronic low back pain patients using a repeated measures design. The study objective was to determine if stochastic resonance (SR) stimulation of the paraspinal muscles improves spine proprioception and trunk postural control. Decreased spine proprioception and larger postural sway have been found in low back pain patients, although several studies have also shown no differences in spine proprioception. Spine proprioception, measuring subjects' sensitivity to change in position, was assessed in 3 orthopaedic planes. Postural control was assessed using an unstable seat with a hemisphere attached to the bottom. Subjects balanced with eyes closed on the most challenging size hemisphere they could manage while center-of-pressure was recorded with a force plate beneath the seat. Both tasks were performed with SR stimulation randomized at 0%, 25%, 50%, and 90% intensity levels. No significant differences in spine proprioception were observed between SR stimulation levels for any of the 3 orthopaedic planes. SR stimulation significantly improved postural control, but only in the lateral plane. No differences in postural control were observed between stimulation levels 25%, 50%, and 90% in the lateral plane. There was no correlation between spine proprioception and postural control. Results suggest that SR stimulation to the paraspinal muscles can improve postural control; however, this improvement cannot be attributed to improved spine proprioception based on the current study. People with compromised neuromuscular control or those exposed to unstable environments may benefit from SR stimulation.