Energy spectral density as valid parameter to compare postural control between subjects with nonspecific chronic low back pain vs healthy subjects: A case-control study

Background: Nonspecific chronic low back pain (NSCLBP) is one of the most common and frequent health problems. Objetive: to compare postural control (i.e. center of pressure (CoP) displacement and energy spectral density (ESD)) using technological devices (accelerometers and pressure platform) between subjects with NSCLBP and healthy subjects. Methods: A cross-sectional case-control study was conducted. Observational study (STROBE). The final sample consisted of 60 subjects (30 NSCLBP subjects and 30 healthy subjects). Triaxial accelerometer and pressure platform were used in order to obtain ESD and CoP displacement measurements during four balance tasks (i.e. with and without vision and on stable versus unstable surface). Independent t tests were used to compare participants with NSCLBP and healthy controls in the two clinical measurements (i.e., CoP displacement and ESD) for the four balance tests. A multivariate analysis of variance (MANOVA) together with a Fisher's linear discrimination was applied in order to categorize NSPLBP. Results: Patients with NSCLBP showed greater CoP migration in the positions eyes open, stable surface on the anteroposterior axis (p = 0.012), eyes closed, stable surface on the mediolateral axis (p = 0.025), eyes closed, stable surface on the anteroposterior axis (p = 0.001), eyes open, unstable surface on the anteroposterior axis (p = 0.040), eyes closed, unstable surface on the anteroposterior axis (p = 0.015). Also the ESD was significantly greater for the four situations described (p <= 0.01) in subjects with NSCLBP. Conclusions: Accelerometer appears to be a technological device that could offer a potential benefit within the battery of tests on physical performance among subjects with NSCLBP and healthy subjects.