Balance impairment in people with multiple sclerosis: Preliminary evidence for the Balance Evaluation Systems Test Jesse V. Jacobs *, Susan L. Kasser Department of Rehabilitation and Movement Science, University of Vermont, 305 Rowell Building, 106 Carrigan Drive, Burlington, VT 05405, USA 1. Introduction Multiple sclerosis (MS) represents a common and disabling neurologic disease associated with impaired postural control and, consequently, impaired mobility with an increased risk of falls [1]. People with MS exhibit altered postural control across several contexts of behavior, including stance under challenging sensory conditions, leaning or reaching to the limits of stability, postural responses to a loss of balance, continuous gait, and anticipatory postural adjustments (APAs) (reviewed in [2]). Although several clinical assessments of gait or balance have been validated to identify differences between individuals with MS who report a recent fall history from those without a recent fall history [3], these scales do not encompass all of the contexts of balance impairments associated with MS. It would therefore be beneficial to identify the constellation of balance impairments associated with having MS as well as to identify a single clinical instrument that is capable of assessing balance impairments across each of these contexts for people with MS. The Balance Evaluation Systems Test (BESTest) represents a 36- item balance assessment that was recently developed to assess balance impairments across six contexts of postural control: mechanical constraints, limits of stability, APAs, postural responses to an induced loss of balance, sensory orientation in stance, and gait [4]. The BESTest was reported to exhibit high levels of inter-rater and test-retest reliability [4,5]. BESTest scores associate with balance confidence in subjects with and without balance disorders [4,6], are sensitive to retrospective and prospective fall reports in subjects with Parkinson’s disease [5,7], and differentiate people with and without fibromyalgia [8]. The BESTest, however, has not been validated as an assessment of balance impairment in people with MS, nor has it been validated with objective recordings of balance performance. This study, therefore, sought to broaden the scope of the BESTest’s validity by examining its efficacy to identify balance impairment in people with MS. Beyond simply applying the BESTest to a new clinical disorder, we also provide a novel test of validity for the BESTest by relating the BESTest’s scores to objective laboratory measures of postural performance. Scores were further related to the subjects’ disease severity and reported fall history. We hypothesized that the BESTest would represent a valid clinical measure of postural impairment in people with MS. We thus Gait & Posture 36 (2012) 414–418 A R T I C L E I N F O Article history: Received 30 January 2012 Received in revised form 23 March 2012 Accepted 28 March 2012 Key words: Balance Evaluation Systems Test Multiple sclerosis Posture Balance Falls A B S T R A C T This study examined the validity of the Balance Evaluation Systems Test (BESTest) to identify balance impairments in people with multiple sclerosis (MS) by evaluating differences in BESTest performance between people with and without MS. We also assessed the BESTest’s validity by correlation with objective measures of postural performance as well as with disease severity and fall status. Thirteen subjects with MS (Expanded Disability Status Scale; EDSS: 0–4.5) and 13 matched subjects without MS were evaluated on the BESTest, asked about fall history, and assessed by force plates and motion capture as they performed laboratory tasks of step initiation, forward leaning to the limits of stability, and postural responses to rotations of the support surface. Compared to subjects without MS, subjects with MS exhibited lower total BESTest scores (mean (95%) score for subjects with MS = 91 (83–99); subjects without MS = 105 (104–107)) as well as section scores pertaining to mechanical constraints, limits of stability, anticipatory postural adjustments, and gait. BESTest scores significantly correlated with objective laboratory measures of step velocity during step initiation (Pearson r 2 = 0.48, P < 0.01) as well as center-of-pressure displacements during both the leaning (Pearson r 2 = 0.55, P < 0.005) and postural- response tasks (Pearson r 2 = 0.76, P < 0.0001). BESTest total scores were 92% accurate to identify fallers and non-fallers, and BESTest scores significantly correlated with EDSS scores (Spearman’s rho = 0.85, P < 0.0005). Thus, the BESTest provides a valid clinical assessment of balance impairments in people with MS. ß 2012 Elsevier B.V. All rights reserved. * Corresponding author. Tel.: +1 802 656 8647; fax: +1 802 656 6586. E-mail address: jjacobs@uvm.edu (J.V. Jacobs). Contents lists available at SciVerse ScienceDirect Gait & Posture jo u rn al h om ep age: ww w.els evier.c o m/lo c ate/g aitp os t 0966-6362/$ – see front matter ß 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.gaitpost.2012.03.026