Validation of a wearable sensor insole device for analysis of postural control

Postural control is a complex system in which the nervous system regulates information from various sensory systems, leading to corrective movement via the musculoskeletal system to maintain upright stance. When one or more of these systems is impaired, a person’s balance can be negatively affected. To determine the root cause of balance complications, a person may undergo clinician-supervised qualitative tests, which can be subjective in nature and may not detect small changes over time which contribute to balance issues. A new technology, the OpenGo SCIENCE (Moticon GmbH, Germany), is a pair of sensor insoles which applies wearable technology to evaluate motion. 20 subjects, aged 20-25, conducted 10 bipedal stance trials (5 eyes-open, 5 eyes-closed) wearing the OpenGo in-shoe and on a research-grade force plate simultaneously. A selection of linear, nonlinear, and frequency-domain measures of postural control were compared between the two devices to assess the validity of the OpenGo for analysis of quiet stance. It was found that COP range and RMS (AP-direction), 95% confidence ellipse area, approximate and sample entropy (ML-direction), median frequency, and low-frequency power ratio are considered valid to use for balance assessment using the sensor insole device, but special care must be taken during data post-processing.