Thalamic stimulant

The thalamic stimulator was first approved for medical use in the United States on August 4, 1997, when the FDA , based on the results of randomized clinical trials , approved its use in medicine for the treatment of tremors associated with Parkinson's disease and essential tremor ^[2] .

Thalamic stimulator implantation is an invasive surgical procedure that carries with it the risk of side effects and complications, including sometimes severe and irreversible ones. Therefore, the implantation of a thalamic stimulator, as a treatment method, is usually reserved for use only in patients with severe enough, disabling tremor, and only in cases where other treatment methods do not help, or help weakly and insufficiently, that is, when the patient turned out to be fully or partially resistant to more traditional or standard methods of treatment, for example, pharmacological or to the use of biological feedback techniques and non-invasive methods of brain stimulation, such as transcranial magnetic stimulation .

The thalamic stimulator implantation operation is reduced to the fact that one or several electrodes are implanted in the patient's thalamus , in those of its nucleus , which are responsible for communication with the striatum , cerebellum and motor cortex, for controlling movements and controlling muscle tone. The electrodes coming from the thalamus are connected to the subcutaneous wires leading to the thalamic stimulator itself, which can also be implanted, or can be connected externally, like a wearable device. In the case of implantation in the body, the thalamic stimulator itself is usually implanted not in the cranial cavity, but, for example, under the muscles of the chest .

To obtain optimal results for the implantation of a thalamic stimulator, as in the case of many other neurosurgical interventions, it is important that the patient is conscious during the operation and speak with the surgeon, reporting sensations from the stimulation of one or another part of the brain during electrode advancement. After implantation, the device can be configured or programmed by a doctor to supply pulses of a particular frequency, duration, amplitude and duty cycle. It can also be turned on and off by the patient himself throughout the day. This flexibility of modern thalamic stimulants provides better therapeutic efficacy and better tolerance of thalamic stimulation compared to the less flexible programmable and non-disconnectable thalamic stimulants used in the early stages of the development of this technology.

The implantation of a thalamic stimulator significantly changes the picture of the electrocardiogram and electroencephalogram , and leads to the appearance of artifacts on them associated with the presence and operation of the thalamic stimulator ^[7] . In addition, the thalamic stimulator, like many other types of implantable medical devices, is incompatible with magnetic resonance imaging scanners , magnetic security controls at airports and other public places, as well as other sources of strong electromagnetic radiation , such as television and radio towers or cell-phone transponders. Patients with an implanted thalamic stimulant should not be subjected to magnetic resonance imaging, and it is not recommended to pass the magnetic safety control framework, as well as live close to or work with sources of strong electromagnetic radiation. Nevertheless, despite these limitations, the implantation of a thalamic stimulator is considered to be a better and safer alternative to pallidotomy, thalamotomy or subthalamotomy , since, unlike these surgical interventions, it is not destructive and completely irreversible in its consequences for the brain.

Possible risks, side effects and complications of this surgery include the risk of infection , stroke , bleeding , cerebral hemorrhage , and the likelihood of developing dysarthria .

A literary description of the treatment of epilepsy by implanting thalamic stimulator electrodes in the patient’s thalamus can be found in the science fiction novel by American writer Michael Crichton Human Computer . This novel was released in 1972, 25 years before thalamic stimulants were officially approved by the FDA for medical use. In 1974, based on this novel, Mike Hodges made the movie The Man Carrying Death .