Examining the Influence of Cognition on the Relationship Between Backward Walking and Falls in Persons With Multiple Sclerosis

Abstract

ABSTRACT BACKGROUND: Multiple sclerosis (MS) causes motor, cognitive, and sensory impairments that result in injurious falls. Current fall risk measures in MS (ie, forward walking [FW] speed and balance) are limited in their sensitivity. Backward walking (BW) velocity is a sensitive marker of fall risk and correlates with information processing speed (IPS) and visuospatial memory (VSM) in persons with MS. Backward walking is a complex motor task that requires increased cognitive demands, which are negatively affected by MS; however, whether cognitive function modifies the sensitivity of BW as a fall risk assessment in MS remains unknown. This study examines the influence of cognition on the relationship between BW and falls in persons with MS. METHODS Measures of BW, FW, IPS, VSM, and retrospective falls were collected. Hierarchical regression tested moderation and included an interaction term predicting number of falls. Covariates for all analyses included age and disease severity. RESULTS Thirty-eight persons with MS participated. Although BW, IPS, and covariates significantly predicted the number of falls (R2 = 0.301; P = .016), there was no evidence of moderation. Backward walking, VSM, and covariates also significantly predicted number of falls (R2 = 0.332, P = .008), but there was no evidence of moderation. The FW models generated comparable results. CONCLUSIONS The relationship between BW velocity and falls was not conditional on IPS or VSM in this sample. Larger-scale studies examining additional cognitive domains commonly affected by MS and prospective falls are needed to characterize neurobiological processes relevant to BW and its clinical application in the assessment of fall risk.