Improved Sensation Resulting From Spinal Cord Stimulation for the Treatment of Painful Diabetic Neuropathy: The Possible Role of Stochastic Resonance

Background: Painful diabetic neuropathy (PDN) is a progressive chronic pain condition that significantly affects the quality of life of patients with long-standing diabetes mellitus. In addition to pain reduction, spinal cord stimulation (SCS) was recently associated with sensory improvements. No explanation has yet been offered to explain these findings. Insensate feet limit activities of daily living , may result in debilitating sequelae.Objectives: Neurologic improvement was observed in PDN patients in the Senza-PDN clinical trial. Our objective was to offer a hypothesis to explain these results.Study Design: The prospective, multicenter, open-label Senza-PDN randomized clinical trial was aimed at documenting the value of 10 kHz SCS in addition to conventional medical management, compared with conventional medical management alone in patients with PDN. We formulated an hypothesis to explain the neurologic improvement observed while using SCS in these study patients Setting: This work was conducted in a private setting, outside of a private clinical practice.Results: SCS resulted in an overall decrease in pain for the enrolled PDN patients. An unexpected improvement in neurologic outcomes was also noticed at up to 12 months, which had never been reported before. We hypothesized that stochastic resonance could be the cause of the neurologic improvement observed in the Senza-PDN study in that the waveforms delivered to the spinal cord may have had the unexpected effect of creating noise-enhanced signal processing.Limitations: Further research will have to be performed to confirm the plausibility of the stochastic resonance hypothesis formulated.Conclusions: SCS might have unexpected benefits in patients with PDN beyond pain reduction. The Senza-PDN trial is the first to describe improved sensation in association with SCS. While the mechanism of action are still unknown, we hypothesize that noise-enhanced signal processing via stochastic resonance may explain these results. Stochastic resonance, or the benefit of additional randomness, should be further studied in the context of spinal cord stimulation. SCS programming that optimizes for stochastic resonance should be studied for restoration of sensory and possibly even motor function.