Movement behaviour in patients with chronic neck pain.

BACKGROUND AND PURPOSE: The present study evaluated whether patients with chronic neck pain demonstrate characteristic angular movement deviations during repeated cervical spine movements.

METHOD: Sixteen patients with chronic neck pain and a group of 18 aged-matched healthy control subjects performed 10 repetitive maximal cervical movement cycles (flexion/extension, rotation, lateral flexion) at a self-determined velocity. To collect the kinematic data of the cervical spine, a three-dimensional ultrasonic movement analysis system (Zebris CMS70, Germany) was used. To describe the movement variability in the maximum oscillation amplitudies the intra-subject coefficients of variation (CV %) was calculated. The maximum difference was characterized by the absolute differences between the minimum and maximum oscillation amplitudes of iterated movement cycles. Pain intensity was obtained by visual analogue scales (VAS).

RESULTS

The average pain rating of the patients with chronic neck pain indicated moderate neck pain intensity (3.7 (+/-0.8)). Independent Student's t-tests revealed a significantly decreased range of movement (ROM) in the chronic neck pain group for all anatomic values (p < 0.05), except for the lateral flexion to the right. The maximum differences and variability parameters showed significantly increased values in the chronic neck pain group in all directions (p < 0.001).

CONCLUSION

Maximal cervical ROM was significantly lower, and movement variability was significantly higher, in patients compared with healthy control subjects. The differences of cervical motion variability point towards increased movement irregularities in patients with chronic neck pain. The present study shows evidence to support the hypothesis that additional information may be gained from the analysis of movement variability.