Neurological Impairment as Confounder or Moderater of Association Between Symptoms and Physical Activity in Multiple Sclerosis

The article examines neurological impairment as a possible confounding and moderating influence of the association between symptoms and physical-activity behavior in individuals with multiple sclerosis (MS). The study sample included 292 individuals with a definite diagnosis of MS. Participants completed self-report measures of the frequency and intensity of symptoms, wore an accelerometer for 7 days, and completed self-report measures of physical activity and neurological impairment. Data analyses indicated that symptoms had a statistically significant moderate, negative relationship with physical activity (γ = −.48); the relationship between symptoms and physical activity was statistically significant but attenuated when controlling for neurological impairment (β = −.20); and the relationship between symptoms and physical activity was statistically significant and similar in magnitude for those with symptom-based (γ = −.22) versus gait/ambulation-based (γ = −.35) neurological impairment. These findings support the importance of considering neurological impairment as a confounding influence of the association between symptoms and physical activity in people with MS.