The first successful transcranial magnetic stimulation (TMS) study was performed in 1985 by
Anthony Barker in Sheffield, England.^1 A January, 2007 review panel of the United
States Food and Drug Administration failed to approve a TMS device, stating it had a good
safety record but failed to demonstrate it was effective for the treatment of
depression. Nearly two years later in December of 2008, the FDA approved the use of a
TMS device "for the treatment of Major Depressive Disorder in adult patients who have
failed to achieve satisfactory improvement from one prior antidepressant medication at
or above the minimal effective dose and duration in the current episode."^2
None of the cited sources discusses TMS. This discussion is included in the outline in order
to contrast TMS with CES, a comparison that points to the superior (though still unproven)
efficacy, less side effects, and lower cost of CES. Also, unlike CES, it is difficult to establish a
convincing form of "sham" TMS to test for placebo effects in conscious individuals, due to
the neck pain, headache and twitching in the scalp or upper face associated with the TMS
intervention. "Sham" TMS manipulations can affect cerebral glucose metabolism and MEPs,
which may confound results. This problem is exacerbated when using subjective measures
of improvement. Depending on the research question asked and the experimental design,
matching this discomfort to distinguish true effects of TMS can be an important and
challenging issue.
TMS is classified as a Class II device, placing it, probably only temporarily, at a level of
assigned risk below that of CES. In July 2011 the FDA published a final rule in the Federal
Register that classified the rTMS system into Class II (special controls), "in order to provide a
reasonable assurance of safety and effectiveness of these devices." The rule identified the
rTMS system as, "an external device that delivers transcranial pulsed magnetic fields of
