A Methodological Study On Quantitative Assessment Of Balance Ability

The decline of balance ability of the elderly people leads to an increased falling risk, which will cause serious physical injury and reduce the quality of life. This problem is further highlighted with the fact of rapid aging in China. And the effective prevention of the fall of the elderly is highly required. For this purpose, the evaluation of the balance ability is essential. However, the commonly used instruments in clinic for balance assessments have defects in accuracy and quantitative. To address these issues, the aim of this study is to establish comprehensive and quantitative techniques for balance ability assessment by static, dynamic and reactive balance test. The contributions of this work are summarized as follows:1. The static balance ability was assessed based on a body sway. A platform was developed for measuring the center of pressure (COP) of body sway. Four characteristic parameters were extracted from the time-domain and frequency-domain COP signals to evaluate the static balance ability. The correlation between age and the characteristic parameters was analyzed.2. The dynamic balance ability was assessed based on a gait test. An electronic walking mat was developed for studying the relationship between age and the gait parameters. It was discovered that the dynamic balance can be characterized by six parameters, including speed, stride frequency, right stand phase, etc.3. The reactive balance ability was assessed based on an obstacle crossing test (OCT). The OCT approach was developed by integrating the virtual obstacles with the electronic walking mat. In comparison with the conventional OCT, the proposed approach generates objective results with a safe testing procedure. A self-adaptive available reaction time (ART) strategy was proposed to eliminate the influence of gait speed on OCT.4. A comprehensive model for evaluating the balance ability was proposed based on the theory of Effective Function Comprehensive Evaluation (EFCE). An optimized comprehensive indicator was established based on the extracted characteristic parameters from static balance, dynamic balance and reactive balance. The validity of the comprehensive indicator was assessed by Berg score and the results reveal that the established indicator is efficient for balance ability assessment.The main innovations of this study are:1. Proposed a comprehensive and quantitative method for balance ability assessment from static balance, dynamic balance and reactive balance, which is potential to provide a novel technique for clinical practice and rehabilitation.2. Proposed a novel design that integrated with virtual obstacles and electronic walking mat for OCT. With the help of this design, the objectiveness of reactive balance measurement was ensured. In addition, this approach eliminates the safe risks in OCT by avoiding the accidental fall during tests.3. Developed a novel self-adaptive ART strategy for excluding the influence of gait speed. The novel ART consists of two components:fixed and variable time intervals. The fixed portion is concerned with the difficulty levels of obstacle avoidance. The variable part in ART is determined by the swing time of gait cycle with weighting coefficients. The proposed method for adaptive ART is suitable for arbitrary gait speed in obstacle crossing test and thus enhances the reliability of the test for individuals.In conclusion, this study established objective and quantitative methods for evaluating the balance ability of the elderly. The method can be applied in predicting the risk of fall after further refinements.