Abstract|Pain 2| Volume 357, SUPPLEMENT 1, e94, October 15, 2015

Time course of therapeutic response to mirror therapy for phantom limb pain

      Background: Mirror therapy is an effective treatment for most amputees experiencing phantom limb pain (PLP), yet optimal treatment parameters, including the duration of treatment, have not been established.
      Objective: We sought to delineate the time course of mirror therapy treatment effects patients with major limb loss.
      Methods: We conducted a post hoc analysis of two independent cohorts of persons with lower extremity amputation (N = 29) enrolled in IRB approved research at Walter Reed National Military Medical Center, Bethesda, MD who received mirror therapy daily for 4 weeks. PLP was assessed on each treatment day using the McGill Pain Questionnaire — Short Form (SF-MPQ), measuring 15 pain descriptors on a 0–3 point scale, and overall intensity of pain in the past 24 h using a 100 mm Visual Analog Scale (VAS). Paired t-tests comparing pain at weekly time points to baseline pain were used to detect substantial reductions in pain.
      Results: Paired-sample t-tests showed significant declines in VAS and SF-MPQ scores after the first week (p < .003 and p < .001, respectively), which persisted after two weeks (p < .007 and p < .001) and four weeks (p < .003 and p < .001). Amputees with VAS pain levels ≤60/100 (N = 19) showed a significant decline in pain after only one week, while those with pain levels >61/100 (N = 10) required at least two weeks of treatment.
      Conclusions: These results indicate that the benefits of mirror therapy can be seen after 7–14 days. Since some patients do not benefit from mirror therapy, a trial lasting 1–2 weeks, stratified based on baseline pain, should be sufficient to determine if there will be a therapeutic response at 4 weeks.