Concurrent validity of the inertial sensors for assessment of balance control during quiet standing in patients with chronic low back pain and asymptomatic individuals.

The objective was to investigate the concurrent validity of inertial sensors for measuring balance control in patients with chronic low back pain and asymptomatic individuals. Thirty-nine patients with chronic low back and 39 age- and sex-matched asymptomatic individuals were included. Balance control analysis was performed in quiet standing with two inertial sensors positioned at the lumbar region and the sternum and compared to the results of a force plate. The variables analysed with either device were Root Mean Square (RMS), index of smoothness (JERK), trajectory length (PATH) and area (AREA). Spearman's correlation coefficient investigated the correlation. Patients with chronic low back pain showed moderate correlation with the inertial sensor positioned on the lumbar for RMS (rs = 0.59; p < 0.01), PATH (rs = 0.42, p = 0.01) and AREA (rs = 0.59; p < 0.01) and weak correlation with the inertial sensor positioned on the sternum for PATH (rs = 0.36, p = 0.04). The asymptomatic group showed statistically significant correlations for RMS for the lumbar (rs = 0.38; p = 0.03) and sternum inertial sensor (rs = 0.42; p = 0.02). Inertial sensors showed weak to moderate correlations compared to data obtained from a force plate.