Fluctuations in gait, or gait variability, are closely related to cognitive function in various clinical populations. However, there are limited data on this relationship in multiple sclerosis (MS) patients. This investigation determined whether cognitive function as measured by processing speed is associated with gait variability in individuals with MS. This secondary analysis included 191 individuals with MS who underwent gait assessment and cognitive assessment. Cognitive processing speed was index by symbol digit modalities test (SDMT). Gait variability was indexed by step length and step time coefficient of variation (CV). Hierarchical linear regressions were performed to examine whether SDMT scores would predict step length and step time CV. After adjusting for age, gender, and disability, we found that SDMT was a significant predictor of step time CV (p < 0.001) and step length CV (p = 0.03). Overall, slower cognitive processing speed was significantly associated with greater gait variability. It is speculated that neural damage in MS patients impairs both cognitive processing speed and gait control. This study provides further evidence that motor and cognitive functions are interrelated.
Keywords: Cognitive processing speed; Gait variability; Multiple sclerosis; Walking.