Comparing the effect of Virtual Reality and Pregabalin on Neuropathic pain over only Pregabalin in Traumatic Spinal Cord Injury: A Randomized Controlled Trial

Spinal cord injury (SCI) is an injury to spinal cord leading to motor and/or sensory deficits [1] and by definition excludes isolated injuries to nerve roots [2], may cause function loss, autonomic disturbances and increased morbidity & mortality.

Pain is commonly reported in SCI patients, mainly neuropathic pain [3] Hypothesised that neuropathic pain below and at level of spinal injury is due to exaggerated neuronal responses to stimuli below normal thresholds.[4] The hyperexcitability is due to altered ion receptors and channels, decreased endogenous inhibitory neurons in dorsal horn.[5] Another theory includes changes at supraspinal level like neuroplasticity with primary somatosensory cortex reorganisation. [6-8] Neuropathic pain is also associated with functional changes in thalamus with animal studies showing abnormal patterns of firing in it. [9].

International Association for Study of Pain Neuropathic Pain Special Interest Group [10], recommend pregabalin as first-line treatment for neuropathic pain (NeP), alongside other drugs like tricyclic antidepressants, serotonin–noradrenaline reuptake inhibitors, and gabapentin [11]. The dose for treatment of NeP starts at 150 mg divided into two (BID) or three (TID) doses per day, increasing to 300 mg/day depending on therapeutic indication, increasing to a maximum of 600 mg/day.[12]

In clinical practice however patient may develop early side effects even with 150 mg/day, likely leading to therapy discontinuation so recommendation for low dose, and slowly titrating to therapeutic dose (termed ‘low and slow’ approach) is given [13] with starting dose as low as 25 mg/day (in elderly or frail patients) or 50 mg/day.

Virtual Reality (VR) is a simulated construction of 3D environment using computer and artificial intelligence technology. Current VR systems include head-mounted devices with 3D-glasses, sensory input devices, noise cancellation headphones, body-tracking sensors and input devices like joysticks,[13] forming a multisystem device giving realistic multisensory experience. Technological improvements in VR, offer an alternative solution of several medical conditions and show promise in improving symptoms like pain reduction in short and long term.[13]

The processes underlying effect of VR on pain have been broadly divided into two main types: distraction and neuroplasticity [14] and are believed to contribute to the analgesic effect of VR.

Distraction refers to the short-term diversion of attention away from pain towards an alternative stimulus. VR may act directly and indirectly to reduce pain by “hijacking” of attention, emotion and memory as well as visual, auditory and touch senses.[14] Neuroplasticity contributes to the effects of VR by long-term structural changes in neurons by involving in interactive real-time simulations of scenes or activities, leading to neuroplastic alterations in sensory and motor brain regions.[15]

In clinical practice however patients on pregabalin for neuropathic pain may develop early side effects even with recommended dose of 150 mg/day given over two doses a day. The adverse effects can range from somnolence, oedema, visual disturbances, ataxia, vertigo and euphoria and can likely lead to reason for therapy discontinuation. VR can provide an alternative to current pharmacologic treatment and can be used in addition to pregabalin for neuropathic pain to minimise its side effects, allowing starting dose to be as low as 25 mg/day (in elderly or frail patients) or 50 mg/day, and slowly titrating to therapeutic dose (termed ‘low and slow’ approach) [13]