Cognitive motor interference in patients with multiple sclerosis

Abstract

Patients with multiple sclerosis (PwMS) present cognitive and motor dysfunction. The Cognitive Motor Interference (CMI) could have a negative impact in PmMS’ daily-life activities especially in those situations when the concomitances of these two components are crucial (e.g., walking and talking with someone, cross a traffic light). CMI have been experimentally evaluated based on a dual task paradigm. Recent studies suggest that there is some inconsistence in the literature regarding whether dual task condition differs between PwMS and healthy peers. The objectives of this study were (i) to determine the impact of the CMI in the gait of PwMS by comparing with healthy peers and (ii) to determine which clinical, cognitive and motor, parameters were more associated with dual task gait. Forty-nine PwMS and 15 healthy peers participated in this study. The evaluations were composed by a current clinical evaluation, SDMT cognitive test, visual analogue scale of fatigue and gait evaluated at self-selected and dual task (arithmetic calculations) conditions. Afterward, the dual task cost (DTC), which is the ratio between the velocities of the 2 gait conditions, was calculated. Significant differences in the cognitive and motor performances were found between PwMS and healthy groups ( P = 10 −5 ). However, in terms of DTC, no significant difference was found between groups ( P = 0.12). EDSS score was the only significant parameter able to explain the DTC variance at 8%. The gait at self-selected condition could explain 92% of the variance of the gait at dual task condition. The CMI occurs in the same proportion in both PwMS and healthy persons. Despite the preponderance of the motor component in the DTC and in gait dual task condition, a combined motor and cognitive rehabilitation approach may have better results than a rehabilitation programs based on separated components.