Peripheral neuropathy is the most common complication in individuals with diabetes. 1 Less than one third of individuals with painful diabetic peripheral neuropathy (DPN) achieve greater than 50% pain relief with pharmacologic treatment. 2 There is an unmet need for therapies that manage pain and improve quality of life.
Transcutaneous magnetic stimulation (TCMS) is effective in treating multiple neurologic conditions.3,4 Studies assessing the effect of TCMS on pain associated with DPN have used low intensity stimulation with conflicting results.5,6 Thus far, no studies have examined peripherally delivered high intensity (1.2 Telsa) TCMS in painful DPN.
This pilot study evaluated the safety and efficacy of high intensity TCMS delivered to the feet of participants with painful DPN and was approved by the University of Maryland School of Medicine Institutional Review Board.
Treatment consisted of a single session of 1.2 Tesla magnetic pulses delivered to the plantar and dorsal surfaces of the foot. Each surface received 50 pulses with a 6 second pulse period over 5 minutes. Pain was measured using the Numeric Pain Rating Scale (pain level: 1-10) after 10 steps in stocking feet on a hard floor surface. Pain scores were collected from each foot and then averaged. Scores were recorded before treatment and followed for 28 days after treatment.
Funding for the TCMS device was provided by Zygood, LLC. Study data were independently collected and analyzed by investigators.
A total of ten participants were enrolled, one of which was lost to follow-up. For the nine individuals who completed the study, the mean duration of diabetes was 24.3 years and the mean duration of neuropathy was 11.7 years. Baseline hemoglobin A1c (HbA1c) was 7.77%, (only available for 7 of the participants).
Prior to treatment, baseline pain in each foot was measured. Participants had an average pain score of 5.72 ± 0.97 (mean ± SD). Immediately post-treatment, pain decreased to 1.22 ± 1.79, a 78% improvement, with 5 individuals reporting no pain, i.e., 100% improvement. Reductions in pain were significant up to 7 days post-treatment (P = .0295) (Figure 1). Treatment success, a 3 point or greater decrease in pain from baseline one day post-treatment, was experienced by 6 participants.
Figure 1.
Mean pain scores for TCMS treated participants. Pain scores (n = 9) were recorded on the Numeric Pain Rating Scale following a standard pain measurement walk. Mean responses (symbols) ± SD (error bars) are shown. Stars indicate a P value of .05 or less.
Immediately after TCMS treatment, pain improvement did not correlate with diabetes duration (P = .3818), neuropathy duration (P = .5704), or HbA1c (P = .4409) At 7 days post-treatment, pain improvement correlated with lower HbA1c (P = .0297).
One participant noted worse pain 1 day post-treatment, no other adverse events were observed during treatment or the 28 day follow up period.
In conclusion, one 20-minute session of high intensity TCMS delivered to the feet provided pain relief lasting up to 7 days in individuals with painful DPN. No adverse events were observed with treatment. Based on these findings, high intensity TCMS warrants further investigation as a therapy for painful DPN.
Footnotes
Abbreviations: DPN, diabetic peripheral neuropathy; HbA1c, hemoglobin A1c; TCMS, transcutaneous magnetic stimulation.
Author Contributions: VPR: data analysis, writing- original draft; MS: data collection, data analysis; EML: writing- review and editing; KMM: conceptualization, study design, supervision, writing- review and editing
Ethics Approval: The study was approved by the University of Maryland School of Medicine Institutional Review Board and has therefore been performed in accordance with the ethical standards laid down in the 1964 Declaration of Helsinki and its later amendments.
Consent to Participate: Informed written consent was obtained from all participants prior to entry into the study.
Consent for Publication: The manuscript is approved by all named authors and the order of authors listed in the manuscript has been approved by all authors.
Declaration of Conflicting Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding: The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: Transcutaneous Magnetic Stimulation Device was provided by Zygood, LLC. NIH Fellowship Grant F30DK124986 supported VPR. No other external funding was provided.
Trial Registration: TCMS for the Treatment of Foot Pain Caused By Diabetic Neuropathy, https://clinicaltrials.gov/ct2/show/NCT03596203, ID- NCT03596203
ORCID iD: Kashif M. Munir 
https://orcid.org/0000-0002-1075-1284
Availability of Data and Material: Data will be made available upon reasonable request to the corresponding author.
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