Short-term Effect of Repetitive Transcranial Magnetic Stimulation on Diabetic Peripheral Neuropathic Pain

Background: Approximately half of the patients with long-standing diabetes are known to have diabetic peripheral neuropathy (DPN). Pain from DPN deteriorates quality of life and hinders activities of daily living. Objectives: This study aimed to evaluate the short-term effect of high-frequency (10 Hz) repetitive transcranial magnetic stimulation (rTMS) on the left primary motor cortex (M1) for neuropathic pain in the lower extremities due to DPN. Study Design: A randomized controlled trial. Setting: The outpatient clinic of a single academic medical center. Methods: In this randomized trial, 22 patients with DPN were randomly assigned to the rTMS group (10 Hz stimulation, 5 sessions) or the sham group. A numeric rating scale (NRS) was used to measure pain intensity before treatment and after one day and one week of treatment. Physical and mental health status were evaluated using the Short Form 36-Item Health Survey (SF-36), comprising 2 subscales (physical and mental component scores [PCSs and MCSs]), at one-week posttreatment. Of the 22 included patients, 20 (10 patients in each group) completed the study. Results: In the rTMS group, the NRS score at one day and one week posttreatment was significantly lower than that at pretreatment. The SF-36 PCS and SF-36 MCS were significantly increased one week after the rTMS sessions. However, in the sham group, the NRS score, SF-36 PCS, and SF-36 MCS did not significantly change after the rTMS sessions. Limitations: The small number of included patients and no long-term follow-up. Conclusion: High-frequency rTMS on the left M1 may be useful for managing pain in the lower extremities due to DPN and may improve a patient's the quality of life.