title: Evaluation of sham transcranial direct current stimulation for randomized, placebo-controlled clinical trials.
abstract: BACKGROUND
  Transcranial direct current stimulation (tDCS) has been investigated as therapeutic intervention in various psychiatric and neurologic disorders. As placebo responses to technical interventions may be pronounced in many clinical conditions, it is important to thoroughly develop placebo conditions which meet the requirements for application in randomized double-blind controlled trials.
  
  
  OBJECTIVE
  The two-part experiment reported here aims at evaluating a new sham tDCS condition in healthy subjects and device operators. Sham or active tDCS is delivered after entering a number code to the device and allows blinding of the operator before and during tDCS. The sham mode has no short stimulation period.
  
  
  METHODS
  The experimental sequence was as follows: 1) Evaluation of successful blinding by comparing placebo to active stimulation at prefrontal sites based on the rating of subjects undergoing tDCS, 2) Evaluation of successful blinding by comparing placebo to active stimulation at prefrontal sites based on the operator/observer ratings.
  
  
  RESULTS
  Subjects were not able to distinguish between active and sham tDCS for prefrontal stimulation. Overall there was no relevant discomfort and tDCS was well tolerated. Operators/observers were able to identify sham stimulation based on skin reddening after active, but not after sham tDCS.
  
  
  CONCLUSIONS
  The tDCS sham condition investigated here may be suitable for placebo-controlled trials keeping subjects blind to treatment conditions. However, operators can easily be aware of the condition applied and they should not get involved in rating outcome measures during the course of high standard placebo-controlled trials.
authors: Department of Psychiatry and Psychotherapy, Ludwig-Maximilians University Munich, Nussbaumstr. 7, 80336 Munich, Germany. ulrich.palm@med.uni-muenchen.de
authors: Ulrich
authors: U
authors: Palm
authors: Eva
authors: E
authors: Reisinger
authors: Daniel
authors: D
authors: Keeser
authors: Min-Fang
authors: MF
authors: Kuo
authors: Oliver
authors: O
authors: Pogarell
authors: Gregor
authors: G
authors: Leicht
authors: Christoph
authors: C
authors: Mulert
authors: Michael A
authors: MA
authors: Nitsche
authors: Frank
authors: F
authors: Padberg
mesh_terms: D000328:Adult; D004311:Double-Blind Method; D004599:Electric Stimulation Therapy / Q000009:adverse effects / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D010919:Placebos; D016032:Randomized Controlled Trials as Topic / Q000379:methods*
chemical_list: D010919:Placebos
keywords: Blinding; Sham stimulation; tDCS