Shengai Li, Matthew Davis, Joel E Frontera, Sheng Li

The objective of this study was to examine the effectiveness of a novel nonpharmacological intervention - breathing-controlled electrical stimulation (BreEStim) - for neuropathic pain management in spinal cord injury (SCI) patients. There were two experiments: 1) to compare the effectiveness between BreEStim and conventional electrical stimulation (EStim) in Experiment (Exp) 1 and 2) to examine the dose-response effect of BreEStim in Exp 2. In Exp 1, 13 SCI subjects (6 males and 7 females, history of SCI: 58.2 months, from 7 to 150 months, impairments ranging from C4 AIS B to L1 AIS B) received both BreEStim and EStim in a randomized order with at least 3 days apart. A total of 120 electrical stimuli to the median nerve transcutaneously were triggered by voluntary inhalation during BreEStim or were randomly delivered during EStim. In Exp 2, a subset of 7 subjects received BreEStim120 and 240 stimuli randomly on two different days with 7 days apart (BreEStim120 vs BreEStim240). The primary outcome variable was the visual analog scale (VAS) score. In Exp 1, both BreEStim and EStim showed significant analgesic effects. Reduction in VAS score was significantly greater after BreEStim (2.6±0.3) than after EStim (0.8±0.3) (P<0.001). The duration of analgesic effect was significantly longer after BreEStim (14.2±6 hours) than after EStim (1.9±1 hours) (P=0.04). In Exp 2, BreEStim120 and BreEStim240 had similar degree and duration of analgesic effects. The findings from this preliminary study suggest that BreEStim is an effective alternative nonpharmacological treatment for chronic neuropathic pain in patients suffering from SCI.