Implementation of TMS in Depression
Major depression is a mood disorder characterized by emotional, behavioral and cognitive dysfunction. Individuals having depression history in their families have a higher risk of suffering from depression. Moreover, people with stroke, heart attack, Parkinson disease, cancer and hormonal diseases are also included in the depression risk group.
Sudden changes like the loss of a relative, problems in relationships, financial problems that affect the person’s life may also cause depression. Major depression is a medical disorder affecting 16.1 million people in America. According to the Turkey Health Research report, depression is among the most common diseases observed with a rate of 11% in individuals of 15 years of age or older.(http://www.tuik.gov.tr/PreHaberBultenleri.do?id=18854). Therefore, the treatment of depression becomes highly significant.
The treatment of depression is initially carried out through the combined implementation of psychotherapy and antidepressants. Nevertheless, antidepressant drugs may not immediately show the effects on all patients. Many patients complain about the unwanted side effects of the drugs. In that case, the TMS (Transcranial magnetic stimulation) device becomes prominent for an alternative treatment. Using the impact of the magnetic field it creates, TMS stimulates the neurons in the brain controlling the mood. The TMS device acquired the approval of the FDA (Food and Drug Administration) in 2008 in America for the treatment of unipolar depression patients resistant to the drugs which failed the pharmacological trials.
Implementation of TMS in depression
The functional neuro-imaging studies concerning depression indicate a decline in the left prefrontal cortex activity in general. In high frequency TMS treatment, it is aimed to increase the activation of the left dorsolateral prefrontal cortex (DLPFC) area in the brain.
The standard parameters applied for depression are 4-second pulses at 10 Hz frequency. There is a 26-second period of time (pause) between the pulses, and a session includes 3000 pulses. The stimulation density is determined based on the motor threshold of the person (120% of the motor threshold). Each session lasts for 37 minutes in total.
TMS can be administered in at least 10 sessions in total, each day of the week. The treatment can be renewed in case of a recurrence of the symptoms. It’s not risky in that respect. For instance, in a study carried out abroad, no side effects were observed in a patient who had received 70 sessions for a span of more than 12 months. (Di Lazzaro, 2009). Nevertheless, some patients may complain about headaches and neck pain although these effects are temporary. Remaining seated in a constant position and keeping the head in a fixed position may cause this complaint in the patients.
When the depression scores of the patients receiving the TMS treatment are compared, the longer the application time gets, the higher the TMS effect becomes. The TMS treatment implemented for 6 weeks was shown to be more effective than a 2-week application. (http://www.jove.com/details.php?id=2345)
The left DLPFC area, the main target area of the TMS treatment, is also associated with cognitive skills. Many of the controlled TMS studies showed developments in one or multiple cognitive skills. Nonetheless, like in any other treatment, the effects of TMS may vary from person to person. Genetic factors or the patient’s condition may cause these differences. The studies show that the TMS treatment is effective in 60% of the patients.
The TMS devices being developed upon the development of the technology in recent years are now alternatives to pharmacological treatment and psychotherapy in the treatment of psychiatric disorders. Although its effectiveness is currently accepted solely for the treatment of depression, the studies conducted show that TMS will be a promising device for the treatment of other psychiatric disorders.