Sensorimotor disturbances in chronic neck pain--range of motion, peak velocity, smoothness of movement, and repositioning acuity.

The purpose of this pilot study was to evaluate sensorimotor functions in patients with chronic neck pain with objective and quantitative methods. A group of 16 patients with chronic idiopathic neck pain of insidious onset or whiplash associated disorders (WAD) was compared to an equally sized group of healthy subjects. Kinematics were investigated during voluntary head rotations by measuring range of motion, variability of range of motion (ROM-Variability), peak velocity, and smoothness of movement (jerk index). Repositioning acuity after cervical rotations was evaluated by analysing constant and variable error (VE). In comparison to the healthy subjects, the patients showed significantly larger jerk index, ROM-Variability and VE. No statistically significant differences were found between insidious neck pain and WAD. It is concluded that jerky and irregular cervical movements and poor position sense acuity are characteristic sensorimotor symptoms in chronic neck pain. The observed individuality in sensorimotor disturbances emphasizes the importance of developing specific rehabilitation programs for specific dysfunctions, and of using objective and quantitative methods for evaluation of rehabilitation.