Subjects (N=225) with DPN stage II or III were randomly assigned to use identical devices generating PEMF or sham (placebo) 2 h/d to feet for 3 months.
Interventions
Nerve conduction testing was performed serially.
Main Outcome Measures
Pain reduction scores using a visual analog scale (VAS), the Neuropathy Pain Scale (NPS), and the Patient's Global Impression of Change (PGIC). A subset of subjects underwent serial 3-mm punch skin biopsies from 3 standard lower limb sites for epidermal nerve fiber density (ENFD) quantification.
Results
Subjects (N=225) were randomized with a dropout rate of 13.8%. There was a trend toward reductions in DPN symptoms on the PGIC, favoring the PEMF group (44% vs 31%; P=.04). There were no significant differences between PEMF and sham groups in the NP intensity on NPS or VAS. Twenty-seven subjects completed serial biopsies. Twenty-nine percent of PEMF subjects had an increase in distal leg ENFD of at least 0.5 SDs, while none did in the sham group (P=.04). Increases in distal thigh ENFD were significantly correlated with decreases in pain scores.
Conclusions
PEMF at this dosimetry was noneffective in reducing NP. However neurobiological effects on ENFD, PGIC and reduced itching scores suggest future studies are indicated with higher dosimetry (3000–5000 G), longer duration of exposure, and larger biopsy cohort.
aDepartments of Neurology and Medicine, New York Medical College, Valhalla, NY
bDepartment of Neurology, University of Rochester, Rochester, NY
cDepartment of Neurology, University of Utah, Salt Lake City, UT
dDepartment of Neurology, University of Wisconsin, Madison, WI
eDepartment of Psychology, Emory University, Atlanta, GA
Correspondence to Michael I. Weintraub, MD, 325 S Highland Ave, Briarcliff, NY 10510
Supported by Nu-Magnetics, Inc, who shipped coded devices to various sites under the supervision of a statistician. Nu-Magnetics played no role in the study design, data analysis, interpretation of data, or article development.
Investigational Review Boards at Phelps Memorial Hospital, Sleepy Hollow, NY, and each participating clinical site approved the study protocol and informed consent forms. The clinical trial was preregistered at www.clinicaltrials.gov (NCT 00123136).
No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit on the authors or on any organization with which the authors are associated.
ABSTRACT