Motor Cortical Activation Assessment in Progressive Multiple Sclerosis Patients Enrolled in Gait Rehabilitation: A Secondary Analysis of the RAGTIME Trial Assisted by Functional Near-Infrared Spectroscopy

This study aimed to determine cortical activation responses to two different rehabilitative programs, as measured through functional near-infrared spectroscopy (fNIRS). As a secondary analysis of the RAGTIME trial, we studied 24 patients with progressive multiple sclerosis (MS) and severe disability who were randomized to a regimen of robot-assisted gait training (RAGT) or overground walking (OW). Cortical activation during a treadmill walking task, assessed through fNIRS recordings from the motor and premotor cortexes (M1/PM), was calculated as the area under the curve (AUC) of oxyhemoglobin for each hemisphere and the total area (Tot-Oxy(AUC)). Gait speed, endurance, and balance were also measured, along with five healthy control subjects. At baseline, Tot-Oxy(AUC) during walking was significantly increased in MS patients compared to healthy people and was significantly higher for those with more severe disabilities; it was also inversely correlated with physical performance. After rehabilitation, significant opposite variations in Tot-Oxy(AUC) were observed, with activity levels being increased after OW and decreased after RAGT (+242,080 +/- 361,902 and -157,031 +/- 172,496 arbitrary units, respectively; p = 0.002), particularly in patients who were trained at a lower speed. Greater reductions in the cortical activation of the more affected hemisphere were significantly related to improvements in gait speed (r = -0.42) and endurance (r = -0.44). Cortical activation, assessed through fNIRS, highlighted the brain activity in response to the type and intensity of rehabilitation.

Automated summary

This study used fNIRS to determine cortical activation responses to two different rehabilitative programs for patients with progressive MS, finding that robot-assisted gait training and overground walking had distinct effects on cortical activation, which were related to improvements in gait speed and endurance.