Postural Stability Evaluation of Patients Undergoing Vestibular Schwannoma Microsurgery Employing the Inertial Measurement Unit

Abstract

The article focuses on a noninvasive method and system of quantifying postural stability of patients undergoing vestibular schwannoma microsurgery. Recent alternatives quantifying human postural stability are rather limited. The major drawback is that the posturography system can evaluate only two physical quantities of body movement and can be measured only on a transverse plane. A complex movement pattern can be, however, described more precisely while using three physical quantities of 3-D movement. This is the reason why an inertial measurement unit (Xsens MTx unit), through which we obtained 3-D data (three Euler angles or three orthogonal accelerations), was placed on the patient's trunk. Having employed this novel method based on the volume of irregular polyhedron of 3-D body movement during quiet standing, it was possible to evaluate postural stability. To identify and evaluate pathological balance control of patients undergoing vestibular schwannoma microsurgery, it was necessary to calculate the volume polyhedron using the 3-D Leibniz method and to plot three variables against each other. For the needs of this study, measurements and statistical analysis were made on nine patients. The results obtained by the inertial measurement unit showed no evidence of improvement in postural stability shortly after surgery (4 days). The results were consistent with the results obtained by the posturography system. The evaluated translation variables (acceleration) and rotary variables (angles) measured by the inertial measurement unit correlate strongly with the results of the posturography system. The proposed method and application of the inertial measurement unit for the purpose of measuring patients with vestibular schwannoma appear to be suitable for medical practice. Moreover, the inertial measurement unit is portable and, when compared to other traditional posturography systems, economically affordable. Inertial measurement units can alternatively be implemented in mobile phones or watches.

Effects of vestibular neurectomy and neural compensation on head movements in patients undergoing vestibular schwannoma resection

“…To date, studies comparing vestibular schwannoma patients before and after vestibular neurectomy generally quantified impairments using clinical measures, primarily the VOR but also vestibular evoked myogenic potentials (e.g., 15 – 18 ), and interestingly we found that the widely used VOR measurements were generally not correlated with the head movement parameters we calculated. As noted above, our present quantification of head motion kinematics revealed that pre-op vestibular schwannoma patients could be distinguished from healthy controls during challenging FGA tests.…”

“…Current availability of wearable sensors as well as their accuracy for measuring gait parameters [37][38][39][40] make them suitable for augmenting the information during clinical gait assessments such as FGA. Also, given the importance of head motion in both understanding vestibular processing [41][42][43][44] and diagnosing and treating vestibular disorders 15,22,25,26,[45][46][47][48][49][50][51] , we expect that this field will expand in importance over the next few years and will eventually become an integral component of clinical vestibular medicine.…”