Brain stimulation therapies

Brain stimulation therapies

The progress of neuropsychiatry in the last two decades has determined a kind of leap in the development of brain stimulation therapies, the emergence of new methods and the improvement of old ones. Based on the idea of ​​a functioning brain as a kind of electrochemical organ, its stimulation can indirectly affect therapeutically, correcting pathologically altered functional activity. Traditionally, the “therapeutic niche” of non-drug methods was located where the use of pharmacotherapy is limited by inefficiency or its poor tolerance. At the same time, the scientific achievements of the recent period concerning the neurobiology of mental disorders, as well as the improvement of the technology of devices for brain stimulation, can change the principles of treatment, expanding the clinical indications for the use of brain stimulation methods.
The methods of brain stimulation include electroconvulsive therapy and a number of new techniques, the development and implementation of which takes place in two fundamentally different directions. The first includes safer methods in comparison with ECT and providing local stimulation (TMS, alpha stimulation, direct brain stimulation). The second area includes high-tech invasive methods (vagus nerve stimulation, deep brain stimulation, repetitive transcranial magnetic stimulation, and magnetic seizure therapy) developed by neurosurgeons and psychiatrists.

Electroconvulsive therapy has a rather turbulent 75-year history of use in psychiatry. Having survived periods of bright ups and rapid falls, it is currently a universal and highly effective method of treating extremely severe mental disorders and, at the same time, is perhaps the most stigmatized technique existing in medicine.
Electroconvulsive therapy (ECT), formerly known as electroshock (ES) or electroshock therapy (ECT), is a method of psychiatric and neurological treatment in which an epileptiform seizure is caused by passing an electric current through the patient’s brain to achieve a therapeutic effect.
Electroconvulsive therapy can be applied in various ways, and three main parameters of ECT can vary: the method of applying electrodes to the patient’s head, the frequency of sessions (in some countries, in the UK, ECT is usually performed twice a week, in others twice or thrice week depending on the severity of the condition and other reasons), the shape and parameters of the electrical signal. The choice of anesthetic for general anesthesia, the choice of muscle relaxants and sedation may also vary. Changes in these parameters of ECT, can have significant differences both in the frequency and severity of undesirable side effects, and in effectiveness.
After completing an ECT course, the patient should usually continue to receive medication. After the completion of the main course of ECT, some patients may be recommended to maintain ECT.
Indications for ECT
There is disagreement among experts on the issue of whether ECT can be considered an acceptable first-line treatment or should it be reserved only for those patients who do not receive relief or receive insufficient relief from other treatment methods, such as psychotropic drugs and psychotherapy.
The 2001 recommendations of the American Psychiatric Association (APA) indicate that the main indications for ECT for patients with depression are the lack of a positive effect or insufficient effect of antidepressants and other drugs used to treat depression, or their intolerance or poor tolerance; a history of a previous course or ECT courses with good effect; significant severity and severity of depression and the need for a quick and clear effect (for example, due to the presence of depressive psychosis or a high risk of suicide). The decision to use or not use ECT depends on many factors, in particular, assessing the severity, severity and duration of depression, the presence of psychosis, assessing suicidal risk, assessing the likelihood that other methods of treatment (in particular, medications and psychotherapy) will be effective in this patient , assessing the risk of leaving the patient without treatment, the presence of concomitant personality disorders in the patient, concomitant drug or alcohol dependence, endocrine disorders or the possibility of somatogen of the organic origin of depression (which ECT does not affect or affects less than endogenous depression, but these factors can aggravate the course of depression, be its cause or cause the ineffectiveness of ECT and drugs, and, in addition, contribute to subsequent accusations against doctors that “ECT did not help, but destroyed my life and my memory”), as well as the patient’s personal preferences and his ability to consciously give voluntary informed consent, weighing the risks and potential benefits of ECT in a particular case.

ECT Side Effects
The most common side effects associated with ECT include:
headache
upset stomach
muscle aches
memory loss

Vagus nerve stimulation, also known as VNS therapy is an additional treatment for epilepsy if modern drugs have not yielded the expected result, and traditional surgical interventions cannot be justified.
Even if other treatments have not helped, vagus nerve stimulation (VNS therapy) remains a promising option.
VNS therapy is indicated and approved in many countries as adjunctive therapy, that is, a treatment method used in combination with another method, usually a drug. VNS therapy is indicated to reduce the incidence of epileptic seizures in children, adolescents, and adults with partial seizures.

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Transcranial magnetic stimulation (TMS) is a method that non-invasively stimulates the cerebral cortex using short magnetic pulses. Like transcranial electrical stimulation (TES), TMS is sometimes associated with pain and therefore should be used with caution.
The study of brain inhibitory processes using TMS is possible due to the ability of TMS to stimulate cortical inhibitory neurons. There are several methods for recording inhibitory responses using TMS. The first, methodologically simplest method is to measure the duration of suppression of spontaneous muscle activity after the presentation of a magnetic stimulus (excitation by electromagnetic induction). This method is called the Cortical Silent Period and allows the assessment of long-latent cortical inhibition (GABA-B). This type of inhibitory function is most sensitive to impaired activity of the basal ganglia (for example, with extrapyramidal disorders, dystonia, Parkinson’s disease and other lesions of the basal structures) and therefore its change can serve as an auxiliary indicator in the diagnosis of diseases of the basal ganglia. The disadvantage of this method is that the duration of suppression of muscle activity in response to TMS depends not only on the severity of the inhibitory activity of the cortex, but also on the intensity of TMS.
When stimulating the motor zone of the cerebral cortex, TMS causes a contraction of the corresponding peripheral muscles according to their topographic representation in the cortex. For example, when using a focal eight-shaped electromagnetic coil, the vertex is the most optimal place for stimulation to receive motor responses from the distal muscles of the lower extremities, and to stimulate the motor zone of the hand, it is necessary to move the coil from the vertex laterally by 5-7 cm. Motor responses caused by TMS (Motor Evoked Potentials (MEPs)) can be registered using the electromyography method using electrodes attached to the skin in the area of ​​the muscle (or muscles) that It takes part in the motor reaction to TMS.
Stimulating a selected area of ​​the brain is of great therapeutic benefit in Parkinson’s disease, spontaneous tremor, dystonia, and chronic pain. The history of attempts to use deep brain stimulation in the treatment of neurological disorders is quite long, but significant progress has been made in recent years, especially in the treatment of Parkinson’s disease.

The deep brain stimulation system consists of three elements: an implanted rhythmic generator of electrical activity, which supplies a signal to the corresponding brain core and connection. The generator is a battery-powered neurostimulator placed in a titanium case, which sends electrical signals to the brain that interact with the electrical activity of neurons in the brain core. The signal to the brain is fed by a metal wire coated with an insulating polyurethane shell, ending with four small platinum-iridium electrodes, which are located in a selected place in the brain. It is connected to the generator with an insulated wire passing through the skull outside the head and going further behind the ear to the neck, and then to the subclavian bottom, where the neurosurgeon most often places the generator.
After implantation, the generator can be calibrated remotely by a neurologist, nurse or trained technician to optimize its effect on the symptoms of the disease and minimize possible side effects. The purpose of electrodes that deliver electrical signals to the brain in the treatment of deep brain stimulation in Parkinson’s disease is the subthalamic nucleus

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