Mobile Posturography: Posturographic Analysis of Daily-Life Mobility

Objective: Mobility is crucial to maintain a sufficient quality of life. Posturography should be therefore focused on the investigation of daily-life activities ("mobile posturography"). Nowadays, postural control is often estimated by stance tasks on a force plate under different sensorimotor conditions. This technique applies an indirect approximation of the center of body mass and is not related to tasks required for mobility. An alternative approach would be the direct measurement of body sway during daily-life conditions close to the center of body mass. The present study was aimed at investigating normal age-dependent postural control strategies by analyzing the body sway of male and female subjects in daily-life tasks. Furthermore, the results were compared with data of age-and sex-matched vestibular disorders to determine the sensitivity of the "mobile posturography". Study Design: Prospective study. Patients: The patient group included 76 subjects, and the control group comprised a total of 246 healthy volunteers. Trunk sway measures were performed using the Vertiguard-D device. With the device fixed by a belt at the hip (center of body mass), the subjects had to undergo 14 daily-life tasks under different sensorimotor conditions. Ankle sway was determined during the sensory organization test (SOT) on the BalanceMaster force plate in all patients by estimating the center of body mass from center of pressure changes within the plantar area. Results: A nonlinear relationship between age and body sway was observed in majority of all the conditions. Furthermore, large sex-related differences in body sway were observed. The sensitivity of the mobile posturography was higher than determined during the SOT-force plate measurements or reported in literature before for state-of-the-art platform posturography. Conclusion: The present results indicate that the method introduced here can quantify postural deficits in a broad range and in an inhomogenous sample of patients.