Virtual Walking for Neuropathic Pain in Spinal Cord Injury

Spinal cord injury neuropathic pain (SCI-NP) is a common problem, and when severe, is one of the most problematic of secondary conditions that is minimally to modestly responsive to currently available treatments. It is usually described as burning or stabbing, and is located at or below the level at which their sensation changes from normal to impaired; persons with no feeling at all in their legs for example can experience pain in the legs. The purpose of this project is to further investigate the use of a novel visual stimulation treatment; a technique that has shown benefit in other populations with chronic pain secondary to deafferentation. To accomplish this, a novel treatment - virtual reality (VR) walking - will be examined. Should this treatment show benefit, a portable, accessible means of treatment will be available for persons with SCI and for whom transportation to health care providers is often difficult.

This treatment will be investigated in two-phase project: Phase 1: Determine the efficacy of VR treatments as a home-based approach and determine the effect of VR treatment on reversal of maladaptive cortical reorganization associated with SCI-NP, as has been shown in other populations with neuropathic pain secondary to deafferentation. Phase 2: Determine the effectiveness and immediate analgesic effect of VR treatment among persons with both tetraplegia and paraplegia. The primary outcome variable of this research is the severity of SCI-NP with a secondary outcome of level of pain interference with daily activities. In the phantom pain literature for persons with amputations, treatment paradigms based on visual stimulation, called mirror therapies, have proven helpful. These approaches involve the person viewing a mirror image of their intact limb to produce the visual illusion of a return of the missing limb, often with a marked reduction in pain following. Investigations have demonstrated that such approaches reduce pain in some individuals and that this change is associated with reversal of the functional reorganization in the somatosensory cortex. There has been one study of neuropathic pain in SCI that demonstrated good neuropathic pain relief with a mirror image of the upper half of the individual with SCI with the lower half of their body represented by a rear projection screen generated image of walking legs. We have collaborated with this author, and developed and pilot tested a virtual walking DVD that is presented via virtual reality goggles to enhance the first person sense of immersion. Results were sufficiently encouraging to cause us to seek funding for current, broader project

A 3D video of legs walking from a first person perspective have been developed in consultation with persons with SCI and virtual reality experts. Participants are provided with a 3D monitor and Blue Ray player for daily viewing of the tape for two weeks.

A 3D video was produced of legs in a wheelchair covering the identical conditions of the walking experimental video.

As in mirror therapy for amputee phantom pain, there is evidence that neuropathic SCI pain responds to images of the person with SCI's legs "walking"; we achieve this via a virtual reality approach where the subject perceives it is his/her legs walking.

This control condition mirrors the experimental condition in all respects except it shows still legs in a wheelchair traversing the same path as the virtual walking condition

The NRS is the most commonly used pain rating scale, and ranges from 0/10 to 10/10 with 10 representing unbearable or the "worst possible pain".

Baseline, post 14 day treatment, one week, one month, three months, 6 months post 14 day treatment. Changes in the NRS scale will be the outcome

We will use CASL-fMRI image processing and methods for estimating shifts in cortical somatosensory plasticity

Inclusion Criteria: traumatic onset SCI, at least three months post onset, between 19 and 65; at least 6th grade reading level; neuropathic pain averaging at least 4/10. - Exclusion Criteria: Unable to independently transfer to the fMRI scanning table, current pressures sores, contraindications to scanning; non-compliance with a pre-assignment task. -

Richardson EJ, McKinley EC, Rahman AKMF, Klebine P, Redden DT, Richards JS. Effects of virtual walking on spinal cord injury-related neuropathic pain: A randomized, controlled trial. Rehabil Psychol. 2019 Feb;64(1):13-24. doi: 10.1037/rep0000246. Epub 2018 Nov 8.