Estimulación magnética transcraneana (EMT)

Abstract

Transcranial magnetic stimulation (TMS) is a new neurophysiologic technique that allows the induction of a electrical current in the brain using a magnetic field that can penetrate the subject's scalp and skull. The effect of the magnetic field and the induction of the current in the brain are not painful. The procedure is done while the subject is awake and no anesthesia is needed. There are two kinds of administration: single-pulse TMS and repetitive TMS (rTMS). Single-pulse TMS is the administration of single stimulus. rTMS is the administration of repetitive stimulus to same area of cerebral cortex. TMS is safe and free of side-effects in most situations. However, there are some adverse effects. The principal is the induction of a muscle tension headache or a neck ache in approximately 3 of every 100 subjects studied. These are generally mild and respond easily to an aspirin or acetaminophen. There are relative and absolute contraindications to rTMS. rTMS should not be in patients with metal anywhere in the head, excluding the mouth, in subjects with cardiac pacemakers and implanted medication pumps, in patients with electrodes inside the heart and in persons with increased intracranial pressure. Subjects with a history of seizures or a family history of epilepsy are at increased risk of a seizure and caution is needed when applying rTMS to this persons. TMS is being studied as a potential treatment for depression and other neurologic and psychiatric disorders. Some studies have suggested that repetitive TMS may be very useful instead of electroconvulsive therapy in treatment of drug-resistant depression.