A Quiet Standing Index for Testing the Postural Sway of Healthy and Diabetic Adults Across a Range of Ages

Abstract

A quietstanding index is developed for tracking the postural sway of healthy and diabetic adults over a range of ages. Several postural sway features are combined into a single composite feature C that increases with age a. Sway features are ranked based on the r 2 -values of their linear regression models, and the composite feature is a weighted sum of selected sway features with optimal weighting coefficients determined using principal component analysis. A performance index based on both reliability and sensitivity is used to determine the optimal number of features. The features used to form C include power and distance metrics. The quiet standing index is a scalar that compares the composite feature C to a linear regression model f (a) using C′ (a) = C/f (a). For a motionless subject, C′ = 0, and when the composite feature exactly matches the healthy control (HC) model, C′ = 1. Values of C′ ≫ 1 represent excessive postural sway and may indicate impaired postural control.Diabetic neurologically intact subjects, nondiabetic peripheral neuropathy subjects (PN), and diabetic PN subjects (DPN) were evaluated. The quiet standing indexes of the PN and DPN groups showed statistically significant increases over the HC group. Changes in the quiet standing index over time may be useful in identifying people with impaired balance who may be at an increased risk of falling.

Identification of peripheral neuropathy in type-2 diabetic subjects by static posturography and linear discriminant analysis

“…1, this work confirms previous studies, reporting that DN subjects are less stable than non-neuropathic diabetic patients and normal subjects [3][4][5]9,10,26,27]. The classic parameters detect the qualitative observation that the size of the posturogram is bigger in neuropathic patients than in nonneuropathic ones, particularly in EC condition, when the subject cannot use the visual input and lacks an accurate proprioceptive feedback from the lower limbs.…”

“…The loss of sensory perception secondary to diabetic distal symmetrical sensory neuropathy has a markedly detrimental effect on postural stability during stance and gait [3][4][5] that might contribute to increased fall risk [6,7]. Evaluation of postural steadiness is usually based on the interpretation of centre-of-pressure (COP) measures using a dynamometric platform [8] but only a few studies have addressed the problem of postural instability during quiet standing in DN patients [4][5][6]9,10].…”

“…Evaluation of postural steadiness is usually based on the interpretation of centre-of-pressure (COP) measures using a dynamometric platform [8] but only a few studies have addressed the problem of postural instability during quiet standing in DN patients [4][5][6]9,10]. High correlations have been found in previous works between the severity of neuropathy and the COP measures [6,9,10], but no automatic classification tool based on COP measures has been developed in order to distinguish DN patients from diabetic non-neuropathic subjects.…”

Computational approach to assess postural tests under microgravity conditions

“…This feature of the criterion is very important, because the key measurable parameters of the motion (positions and speed of the selected points) seem to be mutually linked. This may be a reason why some conventional methods, which imply statistical independence of the parameters, sometimes fail to estimate state of imbalance [8]. Another problem with these methods is that they are highly sensitive to noisy and inaccurate data.…”

Wearable static posturography solution using a novel pressure sensor sole

“…For a quantitative evaluation of the ability of a participant to maintain balance, the displacement of the center of gravity (COG) is a meaningful parameter [9]. The COG is the projection of a person's center of mass onto the base of support [9].…”