Repeated Transcranial Magnetic Simulation

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Category: Medical Options

What is it?

Transcranial magnetic stimulation (TMS) is a non-invasive method to excite neurons in the brain. A coil of wire, encased in plastic, is held to the head. The coil is energized by a rapid discharge of a large capacitor, a rapidly changing current flows, producing a magnetic field which passes unimpeded through the skin and skull, inducing an oppositely directed current in specific areas of the brain. Repetitive transcranial magnetic stimulation (rTMS) can produce longer lasting changes.

How does it work?

The weak electric currents applied to the brain, through rapidly changing magnetic fields, are thought to increase brain activity. RTMS can increase or decrease the excitability of nerve pathways in the brain depending on the intensity of stimulation, coil orientation and frequency of stimulation. The mechanism of these effects is not clear although it is widely believed to reflect changes in nerve conductivity in the brain.

Is it effective?

Several small-scale pilot studies have shown it could be a treatment tool for various neurological conditions e.g. migraine, stroke, Parkinsons Disease, dystonia, tinnitus as well as psychiatric conditions e.g. major depression, auditory hallucinations. To date there are no studies assessing the effectiveness of rTMS for PTSD.

Are there any disadvantages?

As it applies an electrical current to the brain, TMS and rTMS can produce a seizure. The risk is very low with TMS except in patients with epilepsy and patients on medications. The risk is higher, when the intensity of the current is increased. Other side effects relate to discomfort or pain from the stimulation of the scalp and associated nerves and muscles on the overlying skin.

Where do you get it?

Only trained professionals in the technique are able to administer this type of treatment. While these strategies are pursued, it is also important that the person with PTSD is under the care of a certified health professional.

What are the evidence limitations?

There is currently no explicit evidence to support TMS and rTMS as an independent intervention for PTSD. Much of the evidence base is derived from lower levels of evidence such as expert opinion and clinical experiences. Therefore interpreting this evidence should be undertaken with caution.

Recommendations

Based on the current lack of high quality evidence, the use of repeated transcranial magnetic stimulation (rTMS) for PTSD cannot be recommended based on the current research evidence. More research is required. It may be considered as an adjunct to other PTSD interventions, such as psychological and pharmacological interventions.

Key References

Australian Centre for Posttraumatic Mental Health 2007, 'Australian guidelines for the treatment of adults with Acute Stress Disorder and Posttraumatic Stress Disorder. Practitioner Guide' National Health and Medical research Council, viewed 11 December 2008,
http://www.nhmrc.gov.au/_files_nhmrc/publications/attachments/mh13.pdf

Fitzgerald, PB, Fountain, S, Daskalakis, ZJ 2006, 'A comprehensive review of the effects of rTMS on motor cortical excitability and inhibition', Clinical neurophysiology, vol. 117, no.12, pp. 2584-2596.

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