The detrended fluctuation analysis (DFA), which is a fractal analysis, has recently been used in the biological field. We investigated the difference in the DFA scaling index between patients with unilateral vestibular disorders (UVD) and healthy adults using time-series data from the left-right and front-back directions of the center of pressure (COP) with closed legs and open/closed eyes. The patients with UVD showed a lower long-range scaling index (αlong) in the time domain in the left-right direction with the eyes closed as compared to the healthy adults. There was a significant negative correlation between the total trajectory length and the short-range scaling index (αshort) in patients with UVD in both the left-right and front-back directions (r=0.64, r=0.68, p<0.05). Vestibular rehabilitation (VR) increased the αlong of the COP time series with the eyes closed in the left-right direction in patients with UVD. VR may be most effective for cases of UVD with higher values of αlong. On the other hand, VR may be partially effective for patients with UVD with lower values of αlong and patients with bilateral vestibular disorder (BVD) with residual vestibular function. We suggest that the values of αlong in the DFA of the COP time series with eyes closed provides useful information for VR for dizzy patients with UVD and BVD.
