Transcranial magnetic stimulation (TMS) is currently one of the most common non-drug treatments for Major Depressive Disorder (MDD) with proven efficacy.
With the help of rhythmic transcranial magnetic stimulation, with a frequency of 10 Hz, for several sessions lasting 20-40 minutes. there is an excitation of the cerebral cortex in the prefrontal cortex (DLPFC). Such an impact leads to a gradual normalization of the rhythms of the brain and contributes to the normalization of a person's mood and the physiological state of his brain. So far, the effectiveness of this application of periodic magnetic stimulation has been proven only for the treatment of depression (major depression disorder - MDD), but numerous studies are underway that try to find new applications of this method.
For the treatment of MDD, as a rule, a typical 10 Hz protocol is used, which has proven its effectiveness. The stimulation frequency of 10 Hz was not chosen by chance - this frequency lies in the middle of the so-called alpha range of 8-14 Hz. The rhythm of the alpha range is considered the normal rhythm of the brain of a healthy awake person. It is also called idle rhythm. It is most pronounced in the state of wakefulness with closed eyes.
But nevertheless, for each person, the peak of the alpha rhythm is individual. For someone it is more, and for someone it is less than 10 Hz.
Is it correct to treat everyone with one protocol at this frequency?
The answer is no.
Currently, a number of studies have been conducted showing an increase in the effectiveness of treating MDD with TMS at an individual alpha peak frequency instead of the traditional frequency of 10 Hz. In addition, there are studies showing a high probability of treatment failure if the individual peak of the alpha rhythm does not exceed 8 Hz. Also, according to the asymmetry of the power of the alpha rhythm, one can more effectively choose the direction of stimulation in the treatment of depression.
All of these studies confirm that rhythmic TMS treatment of MDD can be personalized, thereby increasing its effectiveness.
Thus, in order to increase the effectiveness of the treatment of MDD with rhythmic transcranial magnetic stimulation, a short EEG examination is performed before therapy in order to determine the individual frequency of the alpha rhythm for each patient.
Then, instead of 10 Hz, a stimulation frequency equal to the fixed frequency of the alpha rhythm peak is used to activate the prefrontal cortex of the brain.
EEG recording prior to personalized MDD treatment using TMS will require a specialized disposable electrode system, an electroencephalograph, and a computer with installed EEG processing software.
Unpacking the electrode system:
And getting it ready to go:
Open each electrode:
The disposable electrode system is connected to the electroencephalograph using a special adapter:
After the electrode system is applied to the patient's head, everything is ready to start the EEG examination:
Before starting an EEG recording, it is necessary to check the quality of the placement of the electrodes using the impedance measurement function:
After that, you can proceed directly to the registration of the EEG. Modern software will do everything automatically:
After 1-2 minutes of EEG recording, the program will automatically draw up a report of the conclusion and calculate the individual peak of the alpha rhythm from the spectrum power graphs (Fast Fourier Transform).
To automatically determine the frequency of the alpha peak, it is enough to record only 1-2 minutes of the EEG. The program will calculate the alpha peak and display it on the computer screen. The frequency determination accuracy is 0.1 Hz. Together with the application of electrodes, the entire procedure for registering the individual frequency of the alpha peak takes no more than 5 minutes. This is not much, considering that then this frequency will be used in several dozen sessions of 20-40 minutes each. In addition, the effectiveness of these sessions will be higher, because now you activate exactly the frequency that is the base for your patient.
Thus, by integrating two methods: TMS and EEG, it become possible to increase the effectiveness of non-drug treatment of MDD.
Research in this area continues...