Cognitive-Motor Interference and Cortical Activation While Walking in Individuals With Multiple Sclerosis

Supplementary and Premotor Cortical Activation During Manual Dexterity Involving Motor Imagery in Multiple Sclerosis: A Functional Near-Infrared Spectroscopy Study

BACKGROUND

Investigating brain activation during motor imagery (MI) tasks in people with multiple sclerosis (pwMS) can increase the knowledge of the neural mechanisms underlying motor dysfunction in MS and, hopefully, aid in developing improved rehabilitation strategies.

OBJECTIVE

To investigate brain activation in the supplementary motor area and premotor cortex via functional near-infrared spectroscopy (fNIRS) during a hand manipulation task, and comparing MI with actual practice (AP) in pwMS.

METHODS

Each subject completed a sequence of 4 consecutive manual dexterity trials wearing an fNIRS device. The tasks included the following conditions: AP dominant hand, MI dominant hand, AP non-dominant hand, and MI non-dominant hand.

RESULTS

Twenty pwMS (mean Expanded Disability Status Scale = 4.75 [3.0-6.5]) and 20 healthy controls (HC) participated in the study. According to the fNIRS timeline course, a similar increase (compared with baseline) was observed in the relative oxygenated hemoglobin (HbO) concentration during the MI and AP tasks, which was immediately followed by a decrease (for either hand) in the pwMS and the HC groups. A difference in the relative HbO concentration between the HC and pwMS was detected solely when the 2 groups mentally replicated the manual dexterity task movements in the MI condition (dominant hand). The increase was higher in the HC group (P = .030).

CONCLUSIONS

Despite exhibiting manual dexterity difficulties, pwMS demonstrated comparable neural activation patterns as the HCs during MI tasks in regions associated with motor planning and complex movement control, thus, suggesting that deficits in manual dexterity among pwMS may not solely originate from impairments in the motor planning processes.

Contribution of dual-tasking to social participation in persons with multiple sclerosis: A structural equation modeling approach

INTRODUCTION

This study aimed to explore the patterns of association between dual-tasking, cognition, ambulation disability, fatigue, and self-efficacy and their pathways in predicting social participation in persons with multiple sclerosis (MS).

METHODS

Adults with MS (n = 1162) completed an online survey. Social participation was assessed by the Quality of Life in Neurological Disorders. The Dual-task Impact on Daily-Living Activities Questionnaire, Multiple Sclerosis Walking Scale-12v2, and Modified Fatigue Impact Scale measured dual-tasking, ambulation, and fatigue, respectively. Fall Efficacy Scale-International and Self-Efficacy for Community Mobility were assessed and modeled as a latent variable for efficacy.

RESULTS

The correlation matrix showed significant associations of social participation with dual-tasking, cognition, ambulation, efficacy, and fatigue (all p < 0.001) and interrelationships among the independent variables (p < 0.05). The final model showed excellent global model fit (CFI = 0.99, TLI = 0.96), with all variables significantly predicting social participation either directly or indirectly. Efficacy significantly mediated the effects of dual-tasking (β=-0.32, p < 0.001) and ambulation disability (β=-0.42, p < 0.001) on social participation.

CONCLUSION

This study indicated that dual-tasking, ambulation disability, fatigue, and efficacy play important roles in social participation in persons with MS. The findings can help provide insight into factors that may underpin social participation and offer targets for interventions in persons with MS.

Cognitive function influences cognitive-motor interference during dual task walking in multiple sclerosis

BACKGROUND

Both physical and cognitive impairments are common in people with multiple sclerosis (PwMS). Performing a cognitive task while walking (i.e., dual-task walking) can introduce cognitive-motor interference (CMI), resulting in changes in walking performance. The association between the levels of cognitive impairment and of CMI in MS remains unclear.

OBJECTIVES

To examine the association between cognitive functioning and differences in walking performance arise between single- and dual-task walking.

METHODS

Ninety-five PwMS performed self-preferred pace walking and dual-task walking. The gait parameters recorded were used to compute dual task costs (DTC) as a metric of CMI. Cognitive functioning was assessed using Match, an unsupervised test developed based on the Symbol Digit Modalities Test. Participants were categorized as higher (HCF) and lower cognitive functioning (LCF) based on a Match z-score < -1.5.

RESULTS

LCF group had elevated DTC for stride velocity, relative to the HCF group. Higher DTC for stride velocity was associated with lower cognition, as assessed by Match test.

CONCLUSION

The findings support the hypothesis that CMI is associated with cognitive functioning in PwMS.