Repetitive Transcranial Magnetic Stimulation (rTMS)

What is rTMS?

On the basis of recent research we all know that there is neurobiological process involved in our emotion, memory and behavior. Transcranial Magnetic brain stimulation (TMS) is a technique for gently modulating the brain cells. It utilizes a specialized electromagnet that generates brief magnetic pulses, roughly up to the strength of an MRI scanner’s magnetic field but much more focused. The magnetic pulses pass easily through the skull just like the MRI scanner but because they are short pulses and not a static field, they can modulate the underlying cerebral cortex. It has also been shown that these changes may last for long period of time after stimulation is stopped leading to therapeutic effect.

What disorders has rTMS been shown to be useful for?

TMS is currently a potential treatment for patients with Depression, patients who experience hallucinatory "voices" and a variety of other Psychiatric and Neurological disorders. For patients with Depression, many research studies have shown clinical improvement following rTMS.

For patients reporting auditory hallucinations (voices), research has not been as extensive but initial results have been promising and suggest that low frequency TMS administered to parts of the brain underlying speech perception may reduce these voices.

The Food and Drug Administration (USA) has approved rTMS for Depressive disorder just 3 months back. TMS has been approved in Canada and Israel as a treatment of Depression for patients who have not responded to medications.

What happens in rTMS treatment?

rTMS is an outpatient procedure and does not require anesthesia or sedation. Few patients may experience discomfort at the site of stimulation for short time. Generally rTMS produces a slight tapping sensation on the scalp. When administered at selected stimulation sites it can cause little contraction of the muscles of the scalp. Mild headache and transient lightheadedness may sometimes result from rTMS. These symptoms usually resolve by themselves shortly after the treatment is over.

rTMS Treatment Lab in AIIMS

How long treatment session/course last?

It depends on the treatment/research protocol, but generally each session takes about 20 minutes. Treatment protocols vary in duration, but most require at approximately 10-15 sessions given five times per week.

Are there any risks associated with rTMS?

The brain is directly stimulated by rTMS. However studies reported so far, no loss of memory, impaired concentration and other cognitive impairment. This is in contrast to the well known cognitive side effects associated with Electroconvulsive therapy (ECT)

The main risk of rTMS is rare induction of seizure. However with proper safety guidelines chances of seizures are negligible. For stimulation at low frequency no seizures have been reported.

Why there is interest in rTMS?

1.rTMS has some very unique properties.

2.It is non-invasive, can easily be focused on small areas of the brain, and can modulate the brain cortex at selected site. This makes it particularly well suited for treating several brain disorders, while minimizing side effects.

3.rTMS has been shown to be effective in several psychiatric disorders not responding with currently available medication and other therapies.

4.The rTMS can be also useful in some patients who are not able to take medications.

5.The techniques can be used in the following conditions:

a.Depression

b.Vascular Depression (Depression because of stroke)

c.Obsessive compulsive disorder

d.Migraine

e.Resistant auditory hallucination in Schizophrenia

f.Depression associated with parkinsonism

g.Post traumatic stress disorder

h.Schizophrenia with negative symptoms

i.Chronic tinnitus