Abstract
BACKGROUND: Discrepancies between physiological and perceived fall risk have been identified in multiple sclerosis (MS), but it remains unclear whether these discordant profiles have meaningful correlates. This study examined the relationship between fall-risk concordance and discordance and real-world physical activity, psychological and affective symptoms, and cognitive function. METHODS: Seventy-two ambulatory individuals with MS were classified into four fall-risk groups using median splits of gait speed (physiological risk) and Fall Efficacy Scale-International (FES-I) scores (perceived risk): concordantly high (Hphy-Hper), concordantly low (Lphy-Lper), and two discordant groups (Hphy-Lper; Lphy-Hper). Physical activity (daily steps, moderate-to-vigorous physical activity [MVPA], and sedentary time) was tracked over six months using Fitbit devices. Participants also completed standardized cognitive, psychological, and affective assessments. One-way ANOVAs and residual-based regressions compared outcomes. RESULTS: Approximately 26 % of participants exhibited discordant profiles. The Hphy-Hper group had the lowest activity levels, with fewer steps, less MVPA, and more sedentary time. In contrast, the Lphy-Hper group remained more active despite elevated concern. Collapsed and regression analyses showed that physiological risk was a robust predictor of steps and MVPA, whereas perceived risk was more closely related to sedentary time; discordance itself was not independently associated with activity but was linked with higher fear-avoidance and fatigue. CONCLUSION: Physiological fall risk is most strongly related to real-world activity, while discordance between perceived and physiological risk is more consistently associated with psychological burden. Considering both dimensions may improve profiling and inform person-centered strategies for fall prevention and activity promotion in MS.