Clinical feasibility and preliminary outcomes of a novel mixed reality based system to manage phantom pain for patients with lower limb amputation.: A pilot study

Objective: This report describes the details of Mr. MAPP, a virtual mirror therapy system and the results of a clinical feasibility and evaluation study of a pilot sample of patients with history of lower limb amputation and phantom limb pain. Materials and Methods: Mr. MAPP system uses a Kinect V2 RGB-D camera to capture the patient, generates a live interactive 3D model, and incorporates it into a virtual exergame. Mr. MAPP mirrors their preserved limb and allows participants to visualize their amputated limb virtually and perform their prescribed exercise program. Mr. MAPP creates a digital diary of their therapy sessions by recording game performance and errors. Ten consecutive patients with history of limb loss and phantom pain were targeted for this pilot study. They received a Mr. MAPP system and a laptop for home use for 1-month. Outcome measures including pain intensity and pain interference measured on Numerical Rating Scale (NRS) and McGill Pain Questionnaire (MPQ) as well as functional outcomes measured on Patient Specific Functional Scale (PSFS) were obtained at baseline, and after 1-month. Results: Seven participants were enrolled, out of which four completed the study. The study was temporarily suspended due to restrictions imposed during the COVID-19 public health emergency. In-game performance data showed a trend towards improvement in most participants. Compared to baseline, NRS and MPQ scores at 1-month showed no clear trends. PSFS scores improved for 1 participant and remained unchanged for others. Conclusion: Gamified home exercises performed via a novel, mixed-reality system—Mr. MAPP—using which virtual mirror therapy was delivered, is feasible and has potential to improve pain and pain related function in patients with lower limb amputations and phantom limb pain.