Calmare (Scrambler) therapy is a novel therapeutic modality that purports to provide pain relief by “scrambling” afferent pain signals and replacing them with “non-pain” information through conventional lines of neural transmission. The goal of this study is to identify which factors are associated with treatment outcome for Calmare therapy.
Data were garnered from 3 medical centers on 147 patients with various pain conditions who underwent a minimum of either 3 Calmare therapies on consecutive days or 5 therapies overall. A successful outcome was predefined as ≥50% pain relief on a 0 to 10 numerical rating scale that persisted for longer than 1 month after the last treatment. Variables evaluated for their association with outcome included age, sex, study site, baseline pain score, etiology, type of pain, diagnosis, treatment compliance, coexisting psychopathology, opioid use, antidepressant use, and membrane stabilizer use.
Overall, the success rate was 38.1%. Variables found to be associated with a positive outcome in multivariate logistic regression included the presence of neuropathic (OR=24.78; 95% CI, 2.47-248.97; P=0.006) or mixed (OR=10.52; 95% CI, 1.09-101.28; P=0.042) pain, and treatment at either Walter Reed (OR=6.87; 95% CI, 1.60-29.51; P=0.010) or Seoul National University (OR=12.29; 95% CI, 1.73-87.43; P=0.012). Factors that correlated with treatment failure were disease (OR=0.04; 95% CI, 0.002-0.59; P=0.020) or traumatic/surgical etiologies (OR=0.05; 95% CI, 0.005-0.56; P=0.015) and antidepressant use (OR=0.47; 95% CI, 0.18-1.02; P=0.056).
A neuropathic or mixed neuropathic-nociceptive pain condition was associated with a positive treatment outcome. Investigators should consider these findings when developing selection criteria in clinical trials designed to determine the efficacy of Calmare therapy.
*Department of Anesthesiology and Pain Medicine, Seoul National University Hospital, Seoul National University Cancer Hospital, Seoul, Republic of Korea
†Department of Anesthesiology, Walter Reed National Military Medical Center
∥Departments of Anesthesiology & Physical Medicine & Rehabilitation, Uniformed Services University of the Health Sciences, Bethesda
§Departments of Anesthesiology & Critical Care Medicine and Physical Medicine & Rehabilitation, Johns Hopkins School of Medicine, Baltimore, MD
‡Department of Anesthesiology, Naval Hospital-Camp Lejeune, Camp Lejeune, NC
J.Y.M. and C.K. contributed equally.
The opinions or assertions contained herein are the private views of the authors and are not to be construed as official or as reflecting the views of the United States Department of the Army or the Department of Defense.
Supported in part by a Congressional Grant from the Center for Rehabilitation Sciences Research, Bethesda, MD. The authors declare no conflict of interest.
Reprints: Steven P. Cohen, MD, 550 North Broadway, Suite 301, Baltimore, MD 21029 (e-mail: firstname.lastname@example.org).
Received March 28, 2014
Received in revised form September 25, 2014
Accepted August 27, 2014