When evaluating a patient with diabetic peripheral neuropathy (DPN), it is also important to assess for possible deficits in postural stability. Most clinicians use the Romberg test for balance evaluation. However this is a subjective assessment and does not provide any metric value for screening subject’s balance during treatment. On the other hand the current quantitative methods are not suitable for screening balance control in practice since 1) they need to installation of specific infrastructure such as a force platform, which is costly and requires dedicating specific space, 2) quantification of balance suggested by conventional techniques is based on measurements of center of pressure (COP) in the foot instead of directly measuring the center of mass (COM). This may reduce the power of the test, since the sway area for COP is limited to the contact area of the feet and the space between them. Whereas there is no any boundary for sway area of COM and it depends only on subject’s muscle performance to avoid falling.
Recently our collaboration between Chicago’s Center for Lower Extremity Ambulatory Research (CLEAR) and the University of Arizona’s Southern Arizona Limb Salvage Alliance (SALSA) teams has developed an innovative technology based on miniaturized body-wearable sensors integrated with a two-link biomechanical model of the human body. This technique provides 3D motion of the torso and lower limbs and estimates 2D sway of COM. A new Reciprocal Compensatory Index (RCI) was defined for quantification of Postural Compensatory Strategy (PCS) performance – how movement of lower-limbs could be compensated by an adequate reciprocal interaction of the torso. RCI values may range from 0 to 2. Our results demonstrate that this novel technology is highly sensitive to quantify postural disorders in DPN subjects (see the figure) and discriminates those patients from control healthy subjects. This technology doesn’t require any specific infrastructure and is fully ambulatory thus can be used in any small practice.