Effectiveness of frequency-modulated electromagnetic neural stimulation in the treatment of painful diabetic neuropathy

Aims/hypothesis: The largely unsatisfactory results reported for the pharmacological treatment of diabetic neuropathy has spurred the search for alternative therapies. The aim of this study was to evaluate the efficacy of frequency-modulated electromagnetic neural stimulation (FREMS) as a novel treatment for painful diabetic neuropathy. Methods: Patients (n=31) with painful neuropathy associated with decreased nerve conduction velocity (< 40 m/s) and increased vibration perception threshold (> 25 V) were enrolled in a randomised, double-blind, crossover study designed to compare the effects of FREMS with those of placebo. Each patient received two series of ten treatments of either FREMS or placebo in random sequence, with each series lasting no more than 3 weeks. The primary efficacy end point was the change in pain measured by a visual analogue scale (VAS). Results: FREMS induced a significant reduction in daytime and night-time VAS pain score (all p < 0.02). Furthermore, FREMS induced a significant increase in sensory tactile perception, as assessed by monofilament; a decrease in foot vibration perception threshold, as measured by a biothesiometer; and an increase in motor nerve conduction velocity (all p < 0.01). No significant changes were observed after placebo. Comparison of measurements at the 4-month follow-up with those at baseline revealed that a significant benefit persisted for all measures that showed an improvement at the end of treatment, with an additional improvement in quality of life evaluated by the Short Form-36 questionnaire (all p < 0.05). No significant side effects were recorded during the study. Conclusions/interpretation: FREMS is a safe and effective therapy for neuropathic pain in patients with diabetes and is able to modify some parameters of peripheral nerve function.