Measuring postural stability with an inertial sensor: validity and sensitivity

Abstract

Introduction/purposeTo examine the concurrent validity, and sensitivity, of an inertial sensor for use in the assessment of postural sway.MethodsThis was a laboratory-based, repeated-measures design with ten healthy participants. Concurrent validity was tested between an inertial sensor, forceplate, and rigid-body kinematics across three commonly used balance tests. Further, the inertial sensor measures were compared across eight commonly used tests of balance. Variables manipulated include stance position, surface condition, and eyes-open versus eyes-closed.ResultsThe inertial sensor was correlated to both the forceplate-derived measures (r=0.793) and rigid-body kinematics (r=0.887). Significant differences between the balance tests were observed when tested with the inertial sensor. In general, there was a three-way interactions between the three balance factors (surface, stance, and vision) leading to pairwise comparisons between each balance test. The root-mean-square showed an increase across tasks of greater difficulty ranging from an average of 0.0368 with two legs, eyes-open to 0.911 when tested during tandem stance, eyes-closed tested on a foam pad.ConclusionThe new inertial sensor shows promise for use in the assessment of postural sway. Additionally, the inertial sensor appears sensitive to differences in balance tasks of varying degrees of difficulty when tested in a healthy sample of young adults. This inertial sensor may provide new opportunities for further research in the assessment of balance changes in the mild traumatic brain injury population.

Evaluating physical function and activity in the elderly patient using wearable motion sensors

“…41 In many clinical balance tests such as the Romberg test and the Balance Error Scoring System (BESS), patients keep their eyes closed while performing specific tasks. 42 In the BESS, differences in support surface (foam and firm) and the base of support (single-leg, double-leg, and tandem stance position) across six tasks challenge a person’s balance and wearable IMUs have been used to measure three-dimensional body sway from the centre of mass (COM), hips and ankles.…”

“…42 In the BESS, differences in support surface (foam and firm) and the base of support (single-leg, double-leg, and tandem stance position) across six tasks challenge a person’s balance and wearable IMUs have been used to measure three-dimensional body sway from the centre of mass (COM), hips and ankles. 41 …”

Acute Sport-Related Concussion Screening for Collegiate Athletes Using an Instrumented Balance Assessment

“…Recent efforts have been made to develop technologically advanced measures of balance that are also low cost and convenient for clinicians. 12,[17][18][19][20][21][22][23][24] For example, portable inertial sensors have been validated using both force-platederived measures and rigid-body kinematics. 22 An inertial sensor uses an accelerometer, gyroscope, and magnetometer to give objective data about motion during a balance test.…”

“…12,[17][18][19][20][21][22][23][24] For example, portable inertial sensors have been validated using both force-platederived measures and rigid-body kinematics. 22 An inertial sensor uses an accelerometer, gyroscope, and magnetometer to give objective data about motion during a balance test. 23 A remaining barrier, however, is that these sensors may add costs (ranging from hundreds to thousands of dollars) to the noninstrumented balance testing that is currently conducted.…”

“…Other researchers 12,24 have examined inertial sensors for their potential use during dynamic-gait or dual-task (balance and neurocognitive) or both conditions. Yet they have acknowledged 12,[22][23][24] that additional testing is needed to better understand the value of using inertial sensors post-SRC.…”