Home-Based Transcranial Direct Current Stimulation in Painful Diabetic Peripheral Neuropathy: A Double Blinded,...

To evaluate the analgesic effect of four weeks home-based transcranial direct current stimulation (tDCS) compared with low-intensity sham stimulation in individuals with type 1 diabetes mellitus and painful diabetic peripheral neuropathy.

A total of 35 participants with type 1 diabetes mellitus and painful diabetic peripheral neuropathy were enrolled in a home-based, randomized, double-blind, sham-controlled, crossover study. Each participant underwent four weeks of active (2 mA) and sham (0.3 mA) tDCS in a randomized order. Clinical and experimental end points were assessed before and after each treatment. The primary end point was pain relief, measured daily using a numeric rating scale. Secondary end points included various questionnaires. Quantitative sensory testing was used to assess the pain system.

No significant differences in pain scores were observed after four weeks of active tDCS compared with sham (mean difference in average pain 0.03 (95% CI, -0.40 to 0.46; p = 0.89, mean difference in maximal pain 0.09 (95% CI, -0.42 to 0.60; p = 0.73). However, active tDCS reduced pain compared with baseline: Average pain (p = 0.026) and maximum pain (p = 0.012), unlike sham tDCS. However, taking all four weeks of treatment into consideration, sham tDCS reduced pain scores (p < 0.05). No differences were found between the treatments for the secondary outcomes. Responders to active tDCS showed increased temporal summation and lower pressure pain thresholds.

Active tDCS significantly reduced pain compared with baseline but did not show an improvement over low-intensity sham tDCS. Responders to active tDCS exhibited features of central sensitization. Stimulation intensity may influence tDCS effectiveness.

The clinicaltrial.gov registration number for the study is NCT06152887.