Transcranial magnetic stimulation (TMS) has been studied as a potential therapy for disorders ranging from drug addiction to bipolar disease. The premise is that pulsed, MRI-grade magnetic fields can locally excite or inhibit regions of the cerebral cortex, thus affecting neurological function. The makers of the NeuroStar TMS System, Neuronetics, contacted us to let us know about their new study released at the American Psychiatric Association meeting in May. In brief, they treated patients who have unipolar, non-psychotic Major Depressive Disorder (MDD) with TMS and found that:
Overall, 58 percent of patients achieved a positive response to NeuroStar TMS therapy, with 37 percent of patients achieving remission from their depression.
After an average of five weeks of NeuroStar treatment, the percentage of patients reporting extreme problems with anxiety and depression decreased by 42.2 percent, demonstrating a reduction in depression symptomatology. For overall treatment effect, the percentage of patients reporting no problems in performing usual activities improved by 30.5 percent.
Medgadget had the opportunity to interview Neuronetics’ Chief Medical Officer to discuss the study and the NeuroStar TMS Therapy system.
Shiv Gaglani, Medgadget: What is unique about this study as compared to other studies that show TMS’ effects on depression?
Mark A. Demitrack, M.D.: This study expands on prior work by showing that TMS has effects not just on the symptoms of depression (eg, sadness, anxiety, sleep, libido, appetite, et cetera), but also is able to demonstrate improvements in the ability for a person to resume normal life activities and experience an improved ability to function in day to day activities. In other words, the improvement in mood translates into improvements in real life activities.
Medgadget: How does TMS improve affect among depressed patients? What brain region(s) does it excite/inhibit?
Dr. Demitrack: We believe TMS exerts its effects by improving the metabolic activity (ie, the energy production) in the specific areas of the brain that we know are involved in the regulation of mood. The direct target of action is the left dorsolateral prefrontal cortex (the region right under the left front part of the head). The effects that are exerted there are also exerted indirectly on other areas of the brain that are connected to the DLPFC, including the anterior cingulate cortex, the amygdala and the hippocampus, among others.
Medgadget: What is the strength & penetration depth of the magnetic pulses?
Dr. Demitrack: The magnetic field produced by the NeuroStar TMS system is about 1.5 Tesla, or about the strength of a standard MR imaging device. The magnetic fields reach to a depth of about 3 – 4 cm into the brain directly.
Medgadget: Were any side effects observed?
Dr. Demitrack: The most common side effect directly related to the device is scalp pain or discomfort at the site of stimulation. Most patients find this to be mild to moderate in intensity, and it usually becomes unnoticeable after the first week.
Medgadget: What are NeuroStar’s next steps (e.g. FDA approval, studying TMS in other psychiatric populations)?
Dr. Demitrack: We continue to explore other areas of potential use of TMS in a variety of brain diseases.
Here’s a promo video for the company’s TMS therapy system:
Product page: NeuroStar TMS Therapy System…
