The TMS Committee of the International Federation of Clinical Neurophysiology suggests
that TMS should not be used under these circumstances:
The presence of metal anywhere in the head, excluding the mouth. This includes shrapnel,
and screws and clips from surgical procedures.
TMS also should not be performed in patients with electrodes inside the heart which
might provide a low-resistance current path to electrically sensitive tissue.
Persons with increased intracranial pressure, as in acute large intracranial infarctions
or trauma, are also at increased risk in the event of a seizure, and should not
Safety of TMS during pregnancy has not been established, therefore pregnant women
are not potential candidates for TMS at this time.
Finally, great caution is needed when applying TMS to subjects with a history of
seizures, a family history of epilepsy, and patients taking medication that might
increase the risk of seizures.