title: Transcranial DC stimulation coupled with TENS for the treatment of chronic pain: a preliminary study.
abstract: OBJECTIVE
  Based on evidence showing that electrical stimulation of the nervous system is an effective method to decrease chronic neurogenic pain, we aimed to investigate whether the combination of 2 methods of electrical stimulation-a method of peripheral stimulation [transcutaneous electrical nerve stimulation (TENS)] and a method of noninvasive brain stimulation [transcranial direct current stimulation (tDCS)]-induces greater pain reduction as compared with tDCS alone and sham stimulation.
  
  
  METHODS
  We performed a preliminary, randomized, sham-controlled, crossover, clinical study in which 8 patients were randomized to receive active tDCS/active TENS ("tDCS/TENS" group), active tDCS/sham TENS ("tDCS" group), and sham tDCS/sham TENS ("sham" group) stimulation. Assessments were performed immediately before and after each condition by a blinded rater.
  
  
  RESULTS
  The results showed that there was a significant difference in pain reduction across the conditions of stimulation (P=0.006). Post hoc tests showed significant pain reduction as compared with baseline after the tDCS/TENS condition [reduction by 36.5% (+/-10.7), P=0.004] and the tDCS condition [reduction by 15.5% (+/-4.9), P=0.014], but not after sham stimulation (P=0.35). In addition, tDCS/TENS induced greater pain reduction than tDCS (P=0.02).
  
  
  CONCLUSIONS
  The results of this pilot study suggest that the combination of TENS with tDCS has a superior effect compared with tDCS alone.
authors.affiliation: Núcleo de Neurociências, Centro de Ciências Biológicas e da Saúde, Universidade Presbiteriana Mackenzie, Sao Paulo, Brazil.
authors.forename: Paulo S
authors.initials: PS
authors.lastname: Boggio
authors.forename: Edson J
authors.initials: EJ
authors.lastname: Amancio
authors.forename: Claudio F
authors.initials: CF
authors.lastname: Correa
authors.forename: Sofia
authors.initials: S
authors.lastname: Cecilio
authors.forename: Claudia
authors.initials: C
authors.lastname: Valasek
authors.forename: Zahid
authors.initials: Z
authors.lastname: Bajwa
authors.forename: Steven D
authors.initials: SD
authors.lastname: Freedman
authors.forename: Alvaro
authors.initials: A
authors.lastname: Pascual-Leone
authors.forename: Dylan J
authors.initials: DJ
authors.lastname: Edwards
authors.forename: Felipe
authors.initials: F
authors.lastname: Fregni
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001132:Arm; D001921:Brain / Q000502:physiology*; D002908:Chronic Disease; D003131:Combined Modality Therapy; D004311:Double-Blind Method; D004599:Electric Stimulation Therapy / Q000009:adverse effects; D023381:Endpoint Determination; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D059408:Pain Management; D010147:Pain Measurement; D004561:Transcutaneous Electric Nerve Stimulation / Q000009:adverse effects