Postural control in individuals with and without non-specific chronic low back pain: a preliminary case-control study.

STUDY DESIGN: A preliminary case-control study. OBJECTIVE: To assess postural control in individuals with and without non-specific chronic low back pain (cLBP) during quiet standing. cLBP affects 12-33 % of the adult population. Reasons for pain chronicity are yet poorly known. Change in postural control may be a risk factor for cLBP, although available studies are not conclusive. METHODS: Sample consisted of 21 individuals with cLBP and 23 controls without cLBP. Balance was assessed using a force plate (Balance Master, NeuroCom) by the modified clinical test of sensory interaction and balance, pain severity by the visual analogue scale, quality of life with the SF-36 Questionnaire, and functional disability with the Roland-Morris Questionnaire. RESULTS: Groups were homogeneous for age, weight, height and body mass index. Relative to controls, participants in the cLBP group had deficits in the postural control, with greater postural sway in the quiet standing condition with closed eyes closed on unstable surfaces (p < 0.05) for the following parameters: total COP oscillation [cLBP 1,432.82 (73.27) vs CG 1,187.77 (60.30)], root mean square sagittal plane [cLBP 1.21 (0.06) vs CG 1.04 (0.04)], COP area [cLBP 24.27 (2.47) vs CG 16.45 (1.79)] and mean speed of oscillation [cLBP 12.97 (0.84) vs CG 10.55 (0.70)]. CONCLUSION: Postural control, as evidenced by increased oscillation of COP, is impaired in individuals with cLBP relative to controls. Differences are magnified by visual deprivation and unstable surface conditions.