Prefrontal hemodynamics during forward and backward walking, with and without a cognitive task, in people with multiple sclerosis

BACKGROUND: Hemodynamics in the prefrontal cortex (PFC) while walking forward and backward, with and without an additional cognitive task (motor single-task [ST] and motor cognitive dual-task [DT]) have not been studied in people with multiple sclerosis (pwMS). AIM: To investigate the PFC hemodynamics during forward and as well as backward walking, with and without a cognitive task, in pwMS and healthy controls. DESIGN: Observational case-control study SETTING: Sheba Multiple Sclerosis Center, Tel-Hashomer, Israel. POPULATION: Eighteen pwMS (36.1±11.7 years, 66.6% female) and 17 healthy controls (37.5±13.8 years, 76.5% female). METHODS: Each subject completed four walking trials: ST forward walking, DT forward walking, ST backward walking, DT backward walking. PFC activity for all trials was recorded using functional near-infrared spectroscopy (fNIRS). The PFC was subdivided in the frontal eye field (FEF), frontopolar cortex (FPC) and the dorsolateral PFC (DLPFC). RESULTS: The relative oxygenated hemoglobin (HbO) concentration was higher during the DT forward walking in all PFC subareas compared with the ST forward walking for both groups. The relative HbO concentration was higher during ST backward walking compared with ST forward walking in pwMS (DLPFC, FEF) and the healthy controls (FEF, FPC), specifically during the initial part of the trial. CONCLUSIONS: ST backward walking and DT forward walking impact the hemodynamics at the PFC, although, the difference between pwMS and healthy adults requires further clarification. Future RCT’s are encouraged to examine the impact of an intervention program based on DT forward and backward walking on PFC activity in pwMS. CLINICAL REHABILITATION IMPACT: Backward walking increases activity in the PFC region in pwMS. Similarly, when performing a cognitive task while walking forward.