Efficacy of slow repetitive transcranial magnetic stimulation in the treatment of resistant auditory hallucinations in schizophrenia: a meta-analysis.
OBJECTIVE
Slow repetitive transcranial magnetic stimulation (rTMS), at a frequency of 1 Hz, has been proposed as a treatment for auditory hallucinations. Several studies have now been reported regarding the efficacy of TMS treatment, but results were inconsistent. Therefore, meta-analytic integration of the published trials is needed to evaluate the prospects of this new treatment.


METHODS
A literature search was conducted using PubMed and Web of Science for the years 1966 until February 2006. We used the search terms transcranial magnetic stimulation, TMS, rTMS, and hallucination*.


METHODS
From 15 treatment studies published since 1999, ten were sham-controlled trials and provided sufficient valid information to be included. All studies targeted the left tem-poroparietal cortex using 1 Hz rTMS.


METHODS
Standardized mean gain effect sizes of real rTMS versus sham rTMS were computed based on pretreatment-posttreatment comparisons (computed from mean and SD values or t or F statistics).


RESULTS
After calculation of treatment gain on hallucination ratings using standardized mean differences (sham vs. active rTMS), a mean weighted effect size was computed in the random effects model. We observed a significant mean weighted effect size for rTMS versus sham across the 10 studies, involving 212 patients, d = 0.76 (95% CI = 0.36 to 1.17). When only studies were included that used continuous stimulation (9 studies), the mean effect size increased to d = 0.88 and heterogeneity disappeared. There was no significant effect of rTMS on a composite index of general psychotic symptoms.


CONCLUSIONS
The results of this meta-analysis provide evidence for the efficacy of rTMS as an intervention that selectively alters neurobiologic factors underlying auditory hallucinations.
Aleman
André
A
BCN Neuroimaging Center, University Medical Center Groningen, University of Groningen, the Netherlands. A.aleman@med.umcg.nl
Sommer
Iris E
IE
Kahn
René S
RS
D006212:Hallucinations / Q000209:etiology* / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D016032:Randomized Controlled Trials as Topic; D012559:Schizophrenia / Q000150:complications*; D050781:Transcranial Magnetic Stimulation; D016896:Treatment Outcome