METAANALYSIS OF RANDOMIZED CONTROLLED TRIALS OF CRANIAL ELECTROSTIMULATION - EFFICACY IN TREATING SELECTED PSYCHOLOGICAL AND PHYSIOLOGICAL CONDITIONS

To clarify the diverse published results of cranial electrostimulation (CES) efficacy, we conducted an extensive literature review that iden tified 18 of the most carefully conducted randomized controlled trials of CES versus sham treatment. For the 14 trials that had sufficient d ata, we used the techniques of meta-analysis to pool the published res ults of treating each of four conditions: anxiety (eight trials), brai n dysfunction (two trials), headache (two trials), and insomnia (two t rials). Because studies utilized different outcome measures, we used a n effect size method to normalize measures which we then pooled across studies within each condition. The meta-analysis of anxiety showed CE S to be significantly more effective than sham treatment (p < .05). Po oling did not affect results that were individually positive (headache and pain under anesthesia) or negative (brain dysfunction and insomni a). Most studies failed to report all data necessary for meta-analysis . Moreover, in all but two trials, the therapist was not blinded and k new which patients were receiving CES or sham treatment. We strongly r ecommend that future trials of CES report complete data and incorporat e therapist blinding to avoid possible bias.