Reliability of phantom pain relief in neurorehabilitation using a multimodal virtual reality system

The objective of this study is to demonstrate the reliability of relief from phantom limb pain in neurore-habilitation using a multimodal virtual reality system. We have developed a virtual reality rehabilitation system with multimodal sensory feedback and applied it to six patients with brachial plexus avulsion or arm amputation. In an experiment, patients executed a reaching task using a virtual phantom limb displayed in a three-dimensional computer graphic environment manipulated by their real intact limb. The intensity of the phantom limb pain was evaluated through a short-form McGill pain questionnaire. The experiments were conducted twice on different days at more than four-week intervals for each patient. The reliability of our task´s ability to relieve pain was demonstrated by the test-retest method, which checks the degree of the relative similarity between the pain reduction rates in two experiments using Fisher´s intraclass correlation coefficient (ICC). The ICC was 0.737, indicating sufficient reproducibility of our task. The average of the reduction rates across participants was 50.2%, and it was significantly different from 0 (p <; 0:001). Overall, our findings indicate that neurorehabilitation using our multimodal virtual reality system reduces the phantom limb pain with sufficient reliability.