For patients receiving spinal cord stimulation (SCS) for chronic pain, integration with the immersive virtual reality (VR) system – allowing patients to see and feel the effects of electrical stimulation on the virtual image of their own body – can increase pain – alleviating the effectiveness of SCS, the study reports u BOL®, the official publication of the International Association for the Study of Pain (IASP). The magazine is published by Wolters Kluwer in Lippincott’s portfolio.
The integrated SCS-VR approach improves pain control only over SCS, with fast-acting and long-lasting effects that can be increased by repeated use, according to a new joint study by Dr. Olaf Blanke, of the Ecole polytechnique fédérale de Lausanne (EPFL), Geneva, Switzerland, Dr. Ali Rezai of the Rockefeller Institute of Neuroscience, University of West Virginia, and Dr. Vibhor Krishna of Ohio State University and colleagues. “To our knowledge, this study shows for the first time that it is possible to integrate immersion and multisensory VR with spinal neuromodulation and reduce chronic pain,” the researchers write.
Integrated SCS-VR puts patients on the picture to help them control chronic pain
Dr. Blanke, Rezai, Krishna and their team tested their integrated SCS-VR “digital” method on 15 patients with chronic leg pain. All patients already had SCS implants for chronic leg pain, in most cases due to failed back surgery syndrome.
Spinal cord stimulation uses mild electrical impulses to interrupt pain signals before they reach the brain. Although SCS is an effective and increasingly common treatment for chronic pain, it has limitations: stimulation reduces pain in only about half of patients and rarely completely eliminates pain.
Previous studies have shown that immersive and embodied VR – integrating an image of a patient’s body or avatar into a 3D scene viewed in VR headphones – can have pain-relieving properties. The new approach integrates SCS with VR for the first time, allowing patients to “see” and “feel” the effect of SCS on a virtual image of their own body or avatar in real time. The stimulated area of the patient’s virtual leg, as shown in the VR, “lit up” when electricity was turned on.
For example, if the right thigh was numb during SCS, the same area of the patient’s virtual thigh was illuminated in VR. In the new study, pain scores with integrated SCS-VR were compared with VR alone, with SCS excluded; and with “inconsistent” SCS-VR, with SCS on, but another area of the virtual scene is highlighted.
The results showed lower pain scores when integrated SCS-VR was used. The average pain score (on a continuous visual analog scale) decreased from 6.2 before treatment to 2.72 with “congruent” SCS-VR – when the stimulated leg area “lit up” during SCS. Pain scores decreased by an average of 44 percent with SCS-VR matching, compared with 23 percent with nonconforming SCS-VR. Only virtual reality had little or no impact on the points.
All but 1 of 15 patients had a reduced pain score during SCS-VR. Most importantly, in contrast to the control conditions, the effect lasted for at least ten minutes after the SCS was switched off; repeated applications of SCS-VR had greater effects on pain scores. VR-SCS also caused changes in the “embodiment of the legs” – looking at the VR scene, patients had the impression that they were looking at their right legs, and that the illuminated area was actually causing SCS-induced stinging.
The immersive, personalized SCS-VR approach “combines neuromodulation, VR, and the latest research in the cognitive neuroscience of multisensory integration into a single therapeutic solution,” the researchers write. Integrated VR is a “completely non-invasive” supplement to SCS, with the potential to increase its pain relief effectiveness without adverse effects.
It is not entirely clear how much immersive VR increases the effect of SCS, but new results show that it is not just a distraction effect. Appropriate visual and tactile signals can result in “enhanced masking” of pain intake, suggest others. Blanka, Rezai, Krishna and colleagues. They conclude: “The strength of the effect, its selectivity, ease of administration and consistent increase during sessions and long-term analgesia will facilitate the application of prolonged and more frequent doses of therapy in future SCS-VR studies, which is likely to further enhance the effects described.”
Solca, M., and others. (2020) Enhancement of analgesic spinal cord stimulation for chronic pain with personalized immersion virtual reality. BOL. doi.org/10.1097/j.pain.0000000000002160.