Immediate effect of alone and combined virtual reality, gait-like muscle vibration and transcranial direct current stimulation on neuropathic pain after spinal cord injury: a pilot study

Abstract

Study design: Quasi-experimental pilot study.

Objectives: Evaluate the immediate effect of virtual reality (VR), gait-like muscle vibration (MV) and transcranial direct current stimulation (tDCS) combined or alone on neuropathic pain in individuals with spinal cord injury (SCI).

Setting: Inpatient rehabilitation centre.

Methods: Four participants (two women and two men) with neuropathic pain after SCI participated in the pilot study. All participants received one session per week for four weeks. Each session started with a single-blind administration of active or sham tDCS (20 min) delivered in a pseudo-randomized order, followed by three interventions applied in a pseudo-randomized order (10 min each): gait-like muscle vibration only, watching a walking self-avatar in VR only and the combination of muscle vibration and VR. The intensity of pain was evaluated using a numeric rating scale (0-10, minimal clinically important difference: 2 points) before and after each stimulation.

Results: Participants reported significant reduction of pain (reduction of two points or more) in 4/7 stimulations where VR was associated with muscle vibration, in 1/8 for VR-alone stimulations and in 1/7 for MV-only stimulations. Significant change in pain was found in 1/8 sham tDCS, but not after active tDCS.

Conclusions: Our pilot study showed immediate pain relief when a walking-avatar VR stimulation was associated with gait-like muscle vibration. Even though previous studies supported tDCS for pain reduction, we did not observe any changes in pain after tDCS, likely due to its application once a week. Further research is needed to strengthen these promising results.