Multiple sclerosis and fear of falling: A complex interaction between cognitive network function and EDSS

Cognitive impairments are consistently associated with the actual number of falls and future fall risk in people with multiple sclerosis (PwMS), but their influence and predictive usefulness regarding fear of falling (FoF) are not well understood. Since FoF can greatly affect a patient's lived experience and is essential for evaluating overall fall risk in PwMS, we aimed to explore how cognitive performance relates to, and forecasts, individuals' perceptions of their fall risk, and whether disease severity impacts this relationship.

FoF (Modified Falls Efficacy Scale, MFES) and neurocognitive function (NeuroTrax computerized cognitive assessment battery) were assessed in 188 PwMS. The NeuroTrax battery provided index scores for global cognition and specific cognitive domains such as memory, executive function, attention, processing speed, visuo-spatial, verbal function, and motor skills. The predictive value of cognitive performance on FoF was examined through hierarchical regression models.

Poorer performance on tests of executive function (β = 0.32, p = 0.023) and motor skills (β = 0.24, p = 0.009) were significantly predictive of greater FoF in our broader MS sample. Subgroup analyses showed that for participants with low-to-moderate disease disability, impairment in executive function (β = 0.38, p = 0.023) remained the only significant predictor of FoF in PwMS. Conversely, motor skill impairment (β = 0.38, p = 0.026) was a significant predictor of FoF in participants with higher disease disability. Participants with three or more (n = 47) domains of cognitive impairment had a higher FoF than those with 1-2 (n = 57, p = 0.02) or 0 (n = 76, p < 0.001) impaired domains (F_{(2, 104.55)} = 9.15, p < 0.001).

FoF in PwMS can affect day-to-day planning and quality of life but is often overlooked as a meaningful aspect of the patient's lived experience. Our findings suggest that cognitive deficits are associated with greater FoF, and that the cognitive domain related to FoF varies as a function of disability level. Deficits in executive functioning and motor skills, in particular, may indicate broader disease impact on the patient's perception of their physical capabilities.