Vagus Nerve Stimulation Paired with Physical Therapy to Promote Mobility Rehabilitation in Chronic Ischemic Stroke: A Case Series

Research Objectives: To investigate the effects of physical therapy (PT) paired with vagus nerve stimulation (VNS) on locomotor function in patients following chronic stroke.

Design: A prospective case series with multiple baseline assessments followed by 8 weeks of PT combined with VNS. Reassessments occurred monthly during the intervention period with long-term follow-ups planned at 3 and 6-months. Participants completed a battery of mobility-related assessments to measure change in locomotor outcomes. The results of the first participant to complete the intervention are reported here. All participants will follow a similar intervention protocol; however, each plan of care will be adapted to the participant’s goals.

Setting: A hospital-affiliated outpatient PT clinic.

Participants: The initial participant is a 36-year-old female, 17 months post-ischemic stroke, who plateaued in her mobility rehabilitation. All participants (n=3) have been previously implanted with the Vivistim device for Paired VNS upper extremity rehabilitation, have moderate to severe upper extremity motor impairment, and at least mild mobility impairments at baseline. Participants were excluded if they could not attend weekly therapy sessions or tolerate gait training.

Interventions: The intervention consisted of 45-minutes of in-clinic, PT led therapy at least 1/ week (≥ 8 visits). The intervention was paired with cyclical 0.8 mA, 100 μs stimulation pulses of VNS delivered every 10 seconds throughout the session. The therapy followed clinical practice guidelines to improve locomotor function. Sessions centered on high intensity gait training where patients performed massed practice reciprocal gait activities while maintaining an elevated heart rate. VNS was participant-activated using the same technique as in the home exercise portion of the Vivistim program.

Main Outcome Measures: Primary: Self-selected gait speed (10 Meter Walk Test (10MWT)).
Secondary: Timed measure of walking endurance and capacity (6 Minute Walk Test) and fast gait speed (10MWT).

Results: The participant exceeded a clinically meaningful improvement (MCID = 0.1 m/s) in self-selected gait speed (∆ = 0.11 m/s, % increase = 13%) and improved their timed distance (∆ = 24 m, % increase = 8%, MCID = 34.4 m). There was no change in fast gait speed.

Conclusions: VNS paired with gait training demonstrates clinically meaningful improvements in gait speed and improved endurance following a plateau in recovery. These results support prior work highlighting the potential of self-directed Paired VNS for mobility rehabilitation. Further research into treatment protocols and ideal dosing is warranted.

Author(s) Disclosures: TJ Kimberley is a consultant for Microtransponder Inc., maker of the Vivistim system.

All other authors have no disclosures.