Evaluation of postural stability by means of a single inertial sensor

Human posture control during standing is a combination of many complicated control processes. Physical therapists perform different clinical balance tests to either assess postural control or identify balance disorders that can ultimately cause a patient to fall. In this article, several standardized clinical exercises for balance assessment are executed together with an orientation tracker strapped onto the volunteer's sternum. The tracker estimates the 3-D orientation of the trunk in real-time using an efficient attitude determination algorithm. The device is fully portable and sensitive to anteroposterior and mediolateral sways. Analysis of the resulting angles provides several parameters that are useful in assessing and quantifying balance function. This approach could be a valuable tool for a therapist for patient's follow-up and could be combined with existing procedures such as force platforms or optical motion analysis systems. Also, statistical analysis on these parameters could help to characterize normal and pathological performances in a population.