Safety, ethical considerations, and application guidelines for the use of transcranial magnetic stimulation in clinical practice and research

Abstract

This article is based on a consensus conference, which took place in Certosa di Pontignano, Siena (Italy) on March 7–9, 2008, intended to update the previous safety guidelines for the application of transcranial magnetic stimulation (TMS) in research and clinical settings. Over the past decade the scientific and medical community has had the opportunity to evaluate the safety record of research studies and clinical applications of TMS and repetitive TMS (rTMS). In these years the number of applications of conventional TMS has grown impressively, new paradigms of stimulation have been developed (e.g., patterned repetitive TMS) and technical advances have led to new device designs and to the real-time integration of TMS with electroencephalography (EEG), positron emission tomography (PET) and functional magnetic resonance imaging (fMRI). Thousands of healthy subjects and patients with various neurological and psychiatric diseases have undergone TMS allowing a better assessment of relative risks. The occurrence of seizures (i.e., the most serious TMS-related acute adverse effect) has been extremely rare, with most of the few new cases receiving rTMS exceeding previous guidelines, often in patients under treatment with drugs which potentially lower the seizure threshold. The present updated guidelines review issues of risk and safety of conventional TMS protocols, address the undesired effects and risks of emerging TMS interventions, the applications of TMS in patients with implanted electrodes in the central nervous system, and safety aspects of TMS in neuroimaging environments. We cover recommended limits of stimulation parameters and other important precautions, monitoring of subjects, expertise of the rTMS team, and ethical issues. While all the recommendations here are expert based, they utilize published data to the extent possible.

Long term delivery of pulsed magnetic fields does not improve learning or alter dendritic spine density in the mouse hippocampus

“…Although the mice learned the task, their performance remained suboptimal due to lack of motivation to obtain food rewards through insufficient food restriction 18 and neither learning behaviour, nor hippocampal spine density were affected by long term rTMS. Our negative results are consistent with previous data showing that rTMS has a selective effect on abnormal or injured brain circuitry 19 , and the lack of deleterious side effects observed in normal human subjects 8, 20 .…”

“…The absence of observed behavioural and structural change is consistent with previously reported rTMS specificity for abnormal systems 8, 19 . Furthermore, the lack of adverse effects in our long term study contributes evidence that rTMS is safe to use in healthy control participants 20 .…”

A novel concurrent TMS‐fMRI method to reveal propagation patterns of prefrontal magnetic brain stimulation

“…One participant had to be excluded due to unavailability during the follow‐up session. During the experimental procedure, we strictly adhered to the guidelines and recommendations for TMS endorsed by the International Federation for Clinical Neurophysiology (Rossi et al, 2009). …”

Use of Transcranial Magnetic Stimulation in Bipolar Disorder

“…There is no post-procedure recovery period and no risk of anesthesia. 3,15 The most common side effects are headaches and pain at the site of the stimulation. 3 The estimated risk of TMS-induced seizures and memory impairment is reportedly low.…”

“…3 The estimated risk of TMS-induced seizures and memory impairment is reportedly low. 3,15 There are conflicting findings regarding TMS-induced mania. Three studies did not report a statistically significant increase in manic symptom ratings in bipolar depressed patients during TMS.…”