Vagus Nerve Stimulation Paired With Mobility Training in Chronic Ischemic Stroke: A Case Report

Abstract

Objective: The purpose of this case report is to describe pairing vagus nerve stimulation (VNS) with mobility training in an individual after stroke.

Methods: A 53-year-old man with left hemiparesis 14.2 months after an ischemic stroke participated in a pilot study investigating the safety and feasibility of VNS paired with upper limb rehabilitation. In addition to upper limb impairment, the participant had impaired gait and wanted to improve his mobility. A single-subject design investigation of VNS paired with self-directed mobility training was conducted. Following the conclusion of the pilot study, the participant was instructed to complete daily sessions of self-activated VNS paired with walking or stationary biking. The 10-Meter Walk Test and timed distance (6-Minute Walk Test) were assessed at 4 baseline points and at 3 to 41 months after mobility training.

Results: The participant had stable baseline values and was classified as a household ambulator with a quad cane. After VNS-paired mobility training, statistically significant improvements were observed in all measures, with the greatest improvements at 9 months exceeding the minimal detectable change: self-selected gait speed from 0.34 (standard deviation [SD] = 0.01) to 0.60 meters/second, fast gait speed from 0.37 (SD = 0.03) to 0.79 meters/second, and 6-Minute Walk Test distance from 106.91 (SD = 6.38) to 179.83 meters. The participant reported increased confidence and balance when walking. No falls or adverse events were reported.

Conclusion: The participant demonstrated improved gait speed and timed distance after VNS-paired mobility training. Randomized, blinded trials are needed to determine treatment efficacy.

Impact: This is the first documented case of VNS-paired mobility training in an individual with chronic poststroke gait impairments. VNS paired with mobility training may improve poststroke gait impairments.

Keywords: Case Report; Lower Limb; Mobility; Stroke; Vagus Nerve Stimulation.

Figure 1

Participant’s magnetic resonance imaging scan showing a large right middle cerebral artery stroke with cortical and subcortical involvement. The stroke overlapped with the corticospinal tract and motor cortex. There was adjacent lateral ventricle expansion but little evidence of widespread tissue atrophy or small vessel disease. (A) Longitudinal relaxation time (T1-weighted image) scan, coronal (top), and axial (bottom) views. (B) T1-weighted scan, sagittal (top), and axial fluid-attenuated inversion recovery (bottom) views. (C) and (D) Three-dimensional brain renderings in various planes showing the overlaid corticospinal tract in blue.

Figure 2

Participant’s gait speed (A) and (B) and timed distance (C) over time. The x-axis represents assessment time points. Baseline assessments were completed at B1–B4 (18, 15, 12, and 0 wk, respectively, before the start of vagus nerve stimulation [VNS]-paired mobility training). Mobility training paired with VNS was initiated the day after B4 (black square) and continued for 41 mo (gray shaded area). Posttest assessments occurred between 3 and 41 mo. The horizontal dashed lines represent the mean ± 2 SDs of baseline values, with values above the top line indicating a statistical improvement. The participant self-selected the use of his assistive device (see text for details). *Greater than minimal detectable change. ^Assessments with no assistive device. 6MWT = 6-Minute Walk Test.