Investigating the Effects of Repeated Transcutaneous Spinal Cord Stimulation on Spasticity and Gait in Multiple Sclerosis: A Case Series

Leg spasticity and gait impairments are common symptoms in Primary and Secondary Progressive Multiple Sclerosis (PPMS, SPMS). Transcutaneous Spinal Cord Stimulation (tSCS) has been shown to alleviate these symptoms in individuals with spinal cord injury. Here, we present the first case series (German Clinical Trials Register DRKS00032742) that determines the effect of repeatedly applied tSCS in progressive MS. Nine participants, experiencing spasticity and gait impairments, received 30 min of tSCS (biphasic pulses, 50 Hz) twice a week for four weeks. Before, during, and one week after termination of the treatment, we monitored spasticity with the Modified Ashworth Scale (MAS) and a reduced version of the Tardieu Scale, as well as gait performance, and gait kinematics. Additionally, patient-reported outcome measures were determined. We observed moderate and large effect sizes after seven tSCS treatments in the bilateral MAS (p = 0.34) and bilateral Tardieu sum score, (p = 0.11) respectively. These effects persisted on a moderate level at follow-up. The performance in clinical gait tests showed mixed results with negligible, small and moderate effects at the end of the treatment. Subjective questionnaires revealed a large effect on fatigue and no effect on patient-reported gait deficits. We observed small effects on the range of motion of the hip and knee at the end of the treatment period. This case series suggests that repeated application of tSCS may help reduce spasticity in individuals with progressive MS. These findings highlight the need for further investigation in controlled study designs beyond a single-arm approach, such as randomized controlled trials.