Use of the margin of stability to quantify stability in pathologic gait – a qualitative systematic review

Abstract

Background The Margin of Stability (MoS) is a widely used objective measure of dynamic stability during gait. Increasingly, researchers are using the MoS to assess the stability of pathological populations to gauge their stability capabilities and coping strategies, or as an objective marker of outcome, response to treatment or disease progression. The objectives are; to describe the types of pathological gait that are assessed using the MoS, to examine the methods used to assess MoS and to examine the way the MoS data is presented and interpreted. Methods A systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Guidelines (PRISMA) in the following databases: Web of Science, PubMed, UCL Library Explore, Cochrane Library, Scopus. All articles measured the MoS of a pathologically affected adult human population whilst walking in a straight line. Extracted data were collected per a prospectively defined list, which included: population type, method of data analysis and model building, walking tasks undertaken, and interpretation of the MoS. Results Thirty-one studies were included in the final review. More than 15 different clinical populations were studied, most commonly post-stroke and unilateral transtibial amputee populations. Most participants were assessed in a gait laboratory using motion capture technology, whilst 2 studies used instrumented shoes. A variety of centre of mass, base of support and MoS definitions and calculations were described. Conclusions This is the first systematic review to assess use of the MoS and the first to consider its clinical application. Findings suggest the MoS has potential to be a helpful, objective measurement in a variety of clinically affected populations. Unfortunately, the methodology and interpretation varies, which hinders subsequent study comparisons. A lack of baseline results from large studies mean direct comparison between studies is difficult and strong conclusions are hard to make. Further work from the biomechanics community to develop reporting guidelines for MoS calculation methodology and a commitment to larger baseline studies for each pathology is welcomed.

Small directional treadmill perturbations induce differential gait stability adaptation

“…Third, the excursions of the COM are small with respect to pendulum length ( 19 ), which was likely met in our study due to the small magnitude perturbations. Although all of the assumptions were not likely met in our study, the MOS is a common metric of balance for studies of walking with large perturbations ( 6 , 11 , 23 – 26 , 29 , 30 ) and the proposed approaches to fulfill the MOS assumptions vary among studies ( 83 ).…”

Small Directional Treadmill Perturbations Induce Differential Gait Stability Adaptation

“…Third, the excursions of the COM are small with respect to pendulum length (19), which was likely met in our study due to the small magnitude perturbations. While all of the assumptions were not likely met in our study, the MOS is a common metric of balance for studies of walking with large perturbations (6, 11, 23-26, 29, 30) and the proposed approaches to fulfill the MOS assumptions vary among studies (81).…”

Impact of Sub-Clinical and Clinical Compression Socks on Postural Stability Tasks among Individuals with Ankle Instability

“…Few limitations to this study include the testing of only bilateral stance postural stability tasks, the use of only AJFAT questionnaire to classify groups, the testing of young college-aged population, and the testing for balance only during acute conditions, without any fatigue that might further compromise postural stability, all of which should be addressed in future studies. Furthermore, there could be dynamic changes in mediolateral postural sway that may not have been accounted for with LOS alone [ 39 ], which should be addressed in future research.…”