Blinding success of rTMS applied to the dorsolateral prefrontal cortex in randomised sham-controlled trials: a systematic review.
Level 1 - systematic review of randomized trials
Systematic review of randomized controlled trials
PubMed 21426265 · doi:10.3109/15622975.2010.541281
What was done
Authors systematically reviewed PubMed and Web of Science for randomized sham-controlled trials (RCTs) of repetitive transcranial magnetic stimulation (rTMS) applied to the dorsolateral prefrontal cortex. Regression analyses examined whether participants in active versus sham rTMS groups differed in correctly guessing their treatment allocation and in their likelihood of believing they received real rTMS.
What was found
Only 13 of 96 identified RCTs (13.5%) reported blinding success data. Data from 9 of these 13 studies showed no statistically significant difference between real and sham groups in correctly guessing allocation, though a non-significant trend favored real-group participants guessing correctly. However, participants in real rTMS groups were significantly more likely to believe they had received real stimulation than those in sham groups.
Why it matters
Inadequate sham methods may fail to blind participants effectively, potentially confounding and biasing estimated therapeutic effect sizes in rTMS trials.
Limits
Blinding verification was omitted in 86.5% of eligible RCTs, leaving only 9 studies with extractable data for quantitative analysis. Exact regression effect estimates and confidence intervals were not reported in the abstract, and findings are limited to dorsolateral prefrontal cortex trials.
Cited by
- supports In rTMS clinical trials, sham stimulation effectively blinds participants so they cannot guess whether they received active or sham treatment.