Transcranial Magnetic Stimulation - A Hope For Depression
Transcranial magnetic stimulation is a noninvasive form of brain stimulation that does not require any kind of surgery, insertion of intravenous lines or electrode implantation that uses magnetic fields to stimulate nerve cells in the brain to improvise syndromes of mood disorders like depression. The changing magnetic field implementing electric current at particular areas of the skull through EMI-electromagnetic induction and comes useful in the treatment of depression. The procedure works better with the patients who have shown no successful results while undergoing other effective treatments for depression.
What is depression?
Depression, also known as major depressive disorder is a common and serious illness that negates you feelings; mostly amongst teenagers. It is a serious mood disorder causing a persistent feeling of low mood, stress, sadness and lack of interest. It strongly affects how a person feels, thinks and behaves building a path for many emotional and physical problems. Over a period of time, the person suffering from depression starts feeling unwanted, unworthy, hopeless, guilty and helpless. Feeling burdened by the weight of his or her negatives thoughts and lack of creative ideas, the sufferer stops enjoying his or her life prominently.
Procedure of the treatment
During the procedure, a stimulator is linked to a magnetic coil controlled by a specifically coded computer program which is linked to the scalp called the prefrontal cortex of the patient using anatomical landmarks on the skull. The stimulator produces a charging electric current in the coil inducing magnetic fields; this magnetic field causes an introduction of reversed electric charge in the brain of the person receiving the treatment, precisely on the left side of the brain. As the magnetic fields move in the brain, they produce very small electric currents which activate the cells within the brain and are thought to release neurotransmitters.
Non advisable treatment for some
Although effectively beneficial, the treatment is not advisable for people having any type of non-removable metal implanted in their head, face or neck area like
- aneurysm coils or clips
- metallic implants in eyes or ears of the patient
- stents implanted in neck or brain of the bearer
- deep brain stimulators in the patient’s head
- electrodes in the brain to monitor brain activity
- bullet fragments in or near the patient’s head
- facial tattoos inked with metallic or magnetic sensitive ink
The therapy may cause the object to heat up, move, or sometimes malfunction and subsequently result in a serious injury on the body; sometimes becoming a reason of the death of the bearer.
Adverse effects of the treatment
The treatment is usually considered as a safe and well tolerated therapy for it involves noninvasive methods. The effects vary depending on the frequency and intensity of magnetic pulses as well as on the duration of treatment of the patient. The side effects of transcranial magnetic stimulation are mild, moderate and decreases shortly after additional sessions. The effects generally increase with higher frequency stimulation and have higher risks while dealing with the case of therapeutic TMS. Some of the short term effects are discomfort, pain, hypomania, headaches, cognitive change, hearing loss, impaired working memories, scalp discomfort at the site of stimulation, tingling, spasms, twitching of facial muscles, lightheadedness and inadvertent current induction in implanted devices such as pacemakers. The greatest immediate risks are fainting and seizures which are rarely uncommon.
Hidden Physics behind the therapy
The treatment prominently uses the principle of electromagnetic induction for the production of electric current across the skull and the scalp. The induced magnetic field having the same strength and pulse generated usually reaches not more than five centimeters inside the brain until there is usage of improvised coil and technologies for further stimulation. Transcranial magnetic stimulation is accomplished by discharging the current from a huge capacitor into a coil to generate pulsed magnetic fields having the strength of two and three tesla. The flux generates its own electric field which in turn can cause a shift in trans-membrane currents, causing neurons to be less or more excited respectively. The concept of magnetic field and magnetic flux generation is brought into application using the Biot Savart law and Maxwell Faraday equation respectively.
Length of a session
The therapy involves a series of continuous treatment sessions. Typically, a single session lasts for about 30 to 40 minutes depending upon the coil used and the pulses generated during the treatment. Usually the treatment is for about 4 to 6 regular weeks with patients receiving rTMS 5 days in a week. Since the treatment does not involve any kind of sedation or anesthesia, the patient undergoing the treatment is fully awake and aware throughout the process. The most successful transcranial magnetic stimulation treatment for depression occur when patient undergoes treatments every single weekday for 4 to 6 weeks that means a total of about 20 to 30 therapies. After the daily sessions, the patient can resume to his or her daily activities which can include driving also.
Types of TMS
Variety of TMS has been crafted depending on the recurrence and the order of magnetic pulse generated according to the comfort of the patient. These are as follow.
- single pulse TMS; it releases a sole magnetic pulse at the accustomed time
- Repetitive-pulse TMS (rTMS); it delivers repeated single magnetic pulse of similar intensity to different areas of the brain
- Paired -pulse TMS (ppTMS); it delivers paired pulses at a very high frequency to the brain
- repetitive paired pulse TMS (rppTMS); it delivers paired pulses at a very low frequency to the brain , of about 2 Hz
- Theta-burst stimulation; it consists of short eruptions at fifty to hundred Hz incentive frequencies that are repeated at the theta frequency of 5 Hz and is based on the theta eruption protocols.
Various criterions have been devised using TMS to evaluate the neuronal functions like motor threshold, cortical silent period, neural plasticity, brain mapping and central motor conduction time. The technique has an effective success rate and is being prominently used by doctors all around to curb depression.