title: Longstanding neuropathic pain after spinal cord injury is refractory to transcranial direct current stimulation: a randomized controlled trial.
abstract: Neuropathic pain remains one of the most difficult consequences of spinal cord injury (SCI) to manage. It is a major cause of suffering and adds to the physical, emotional, and societal impact of the injury. Despite the use of the best available treatments, two thirds of people experiencing neuropathic pain after SCI do not achieve satisfactory pain relief. This study was undertaken in response to a recent clinical trial reporting short-term, clinically significant reductions in neuropathic SCI pain with primary motor cortex transcranial direct current stimulation (tDCS). In this investigation, we aimed to build on this previous clinical trial by extending the assessment period to determine the short-, medium-, and long-term efficacy of tDCS for the treatment of neuropathic pain after SCI. We found that, contrary to previous reports, after 5 tDCS treatment periods, mean pain intensity and unpleasantness rating were not significantly different from initial assessment. That is, in this trial tDCS did not provide any pain relief in subjects with neuropathic SCI pain (n=10). A similar lack of effect was also seen after sham treatment. Because the injury duration in this study was significantly greater than that of previous investigations, it is possible that tDCS is an effective analgesic only in individuals with relatively recent injuries and pain. Future investigations comparing a range of injury durations are required if we are to determine whether this is indeed the case.
authors.affiliation: Pain Management Research Institute, Kolling Institute of Medical Research, University of Sydney, Royal North Shore Hospital, St. Leonards, NSW 2065, Australia Sydney Medical School-Northern, University of Sydney, Sydney, NSW 2006, Australia Department of Anatomy and Histology, University of Sydney, Sydney, NSW 2006, Australia Department of Pain Management, HammondCare, Greenwich Hospital, Greenwich, NSW 2065, Australia.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Wrigley
authors.forename: Sylvia M
authors.initials: SM
authors.lastname: Gustin
authors.forename: Leigh N
authors.initials: LN
authors.lastname: McIndoe
authors.forename: Rosemary J
authors.initials: RJ
authors.lastname: Chakiath
authors.forename: Luke A
authors.initials: LA
authors.lastname: Henderson
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Siddall
mesh_terms: D000328:Adult; D000368:Aged; D018592:Cross-Over Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009437:Neuralgia / Q000175:diagnosis / Q000453:epidemiology / Q000628:therapy*; D059408:Pain Management / Q000379:methods*; D010147:Pain Measurement / Q000379:methods*; D013119:Spinal Cord Injuries / Q000175:diagnosis / Q000453:epidemiology / Q000628:therapy*; D013904:Thoracic Vertebrae; D013997:Time Factors; D050781:Transcranial Magnetic Stimulation / Q000379:methods*; D016896:Treatment Outcome
keywords: Below-level neuropathic pain; Clinical trial; Neuropathic pain; Randomised controlled trial; Spinal cord injury; Transcranial direct current stimulation