Postural symmetry evaluation using phase approximations of the follow-up CoP trajectories.

This paper presents a method of postural symmetry evaluation implementing the so-called follow-up posturography. The method boils down to the assessment of similarity of the phase approximation of the counter-clockwise follow-up CoP (Center of Pressure) trajectory and the mirror image against the y-axis of the phase approximation corresponding to the clockwise follow-up CoP trajectory. The usability of the presented approach was tested on the data collected in the group of 30 patients rehabilitated after total hip arthroplasty. The observed difference between the values of the proposed postural symmetry coefficient obtained at the end and at the beginning of the rehabilitation program was statistically significant (p < 0.001). These values, however, were not significantly correlated with the values of postural symmetry coefficients computed in static posturography. Lack of significant correlations between the coefficients supports the reasoning that the new postural symmetry evaluation method quantifies symmetry of posture in terms of dynamic mechanisms, which are not manifested in the case of static posturography. As a major advantage of the herein discussed approach one can distinguish its potential to evaluate postural symmetry in dynamic conditions using relatively inexpensive single-plate posturographic platform.

The follow-up posturography in rehabilitation after total hip arthroplasty.

PURPOSE: Presentation of the results of clinical study on new supplementary method applied in the physical rehabilitation of patients who underwent total hip arthroplasty. The standard rehabilitation program was supplemented with the lower limb loading symmetry training based on the follow-up posturography with an adaptively modified visual biofeedback, performed on a double plate posturographic platform. METHODS: The research involved 60 randomly selected patients included in prospective and comparative clinical study in the scheme of the parallel groups. The subjects were divided into two groups comprised of 30 patients each. In both groups a conventional 21-day rehabilitation was carried out. Additionally, in experimental group the limb loading symmetry restoration training based on the follow-up posturography with an adaptively modified biofeedback was implemented. The biofeedback coefficient reflected the distribution of loading exerted on a given patient's legs and was evaluated during the static posturography examinations carried out before each symmetry training session. RESULTS: The eyes-open static posturography examinations indicated significant improvement in the lower limb loading symmetry in 29 (97%) patients from the experimental group ( p = 0.000003). In the control group, such an improvement was observed in 20 (67%) patients ( p = 0.034796). In the eyes closed examinations correction in the limb loading symmetry was evident in 23 (77%) patients from the experimental group ( p = 0.000247) and 18 (60%) patients from the control group ( p = 0.043327). CONCLUSIONS: Significant improvement in the lower limb loading symmetry was observed in patients who underwent rehabilitation supplemented with the herein discussed training method.