Quantitative Motor Performance Is Indicative of Impairments in Specific Cognitive Domains Among Persons with Multiple Sclerosis

Background: Individuals with Multiple Sclerosis (MS) experience impairments in both motor and cognitive function, yet little is known of the specific relationships among motor and cognitive performance.

Objectives: To explore the relationships among quantitative motor performance and specific domains of cognitive function in persons with MS. 

Methods: Twelve individuals with MS completed the following tests in a single session: gait (i.e., forward walking on GAITRite; Timed Up and Go (TUG); Timed 25 Foot Walk (T25FW);  and Two Minute Walk Test (2MWT)); dual-task/complex gait (i.e. backward walking on GAITRite, Walking While Talking Test (WWWT); Six Spot Step Test (SSST); and TUG-Cognitive (TUGCog)); cognitive testing (i.e., California Verbal Learning Test (CVLT); Delis-Kaplan Executive Function System Sorting (D-KEFS); Paced Auditory Serial Addition Test (PASAT); and Symbol Digit Modalities Test (SDMT)); and quality of life and pain measures (i.e., Short Form-36 (SF-36) and Brief Pain Inventory (BPI)). Spearman correlations were used to examine relationships among motor performance and cognitive domains. 

Results: Performance on simple motor, complex motor, dual-tasks and self-report of quality of life, and pain are related to distinct cognitive domains. Better performance on complex motor and dual-tasks (backward walking stance time, double support time (r<-0.714; p<0.047), SSST (r=-0.786; p=0.021), TUGCog (r<-0.714; p<0.047), WWTT (r<-0.857; p<0.007)) was strongly related with better processing speed (SDMT, PASAT). Better performance on gait measures (forward walking stance time, double support time (r<-0.726; p<0.027), TUG (r=-0.723; p=0.043), T25FW (r=-0.711; p=0.048), 2MWT (r=0.770; p=0.026)) were strongly associated with better executive function (D-KEFS). Finally, lower reports of pain (BPI (r<-0.648; p<0.043)) and higher reports of physical quality of life (SF-36 (r=0.951; p<0.001)) were related to greater verbal learning (CVLT). 

Conclusions: Motor performance, self-reported pain, and quality of life may be used clinically to probe cognitive performance among individuals with MS and provide insight into targeted goals for rehabilitation. Future work will investigate whether quantitative motor tests may serve as biomarkers of early or future cognitive changes.