From Mechanisms to Analgesia: Towards the Use of Non-Invasive Neuromodulation for Pain Relief in the Clinic

Abstract

The use of electricity for analgesic effects has a long history and yet currently neuromodulation devices based on electrical stimulation are typically restricted to being a last resort intervention for pain patients after the failure of pharmacological treatments. Whilst spinal cord stimulation is an established intervention for intractable neuropathic pain, the use of neuromodulation for other forms of pain and targeting different aspects of pain processing is less well established. Non-invasive neuromodulation as part of a standard intervention for pain relief would be ideal for the long term treatment of a chronic pain condition as it would avoid the inevitable side effects associated with long term use of phar-macological interventions or interactions between different drug treatments. This is particularly relevant as chronic pain can be associated with diseases that would require pharmacological treatment for the primary condition. However, there is currently both a deficit in understanding the mechanisms of the different non-invasive devices and also in how these devices may facilitate pain relief for specific conditions. This review will focus on the application of electric currents non-invasively to different sites for pain relief and outline the future potential of these technologies.