On the relationship between pain intensity and postural sway in patients with non-specific neck pain.

Abstract

Increased center of pressure excursions are well documented in patients with non-specific neck pain. While a linear relationship between pain intensity and postural sway has been described in low back pain patients, no such investigation has been conducted in adults with non-specific neck pain. Seventy patients with non-specific neck pain and a matching number of healthy controls were enrolled. Center of pressure parameters were measured by three static bipedal standing tasks of 90 sec duration each with eyes closed on a force platform. The pain intensity was assessed by a numeric rating scale (NRS), an equal number of patients (n=10) was enrolled per pain score. The results confirmed an increased postural sway in pain sufferers compared to healthy controls. In addition, a significant and linear increase in postural sway was observed with higher pain ratings. Statistically significant changes in sway were reached with an incremental change in NRS scores of two to three points. Mean velocity and sway area are closely related to self-reported pain scores in neck pain patients. This relationship has implications for clinical applications such as an objective monitoring tool for patients under treatment or rehabilitation.