A thalamic stimulator is a medical device that can suppress

tremor A tremor is an involuntary, somewhat rhythmic, muscle contraction and relaxation involving oscillations or twitching movements of one or more body parts. It is the most common of all involuntary movements and can affect the hands, arms, eyes, fa ...

s, such as those caused by

Parkinson's disease Parkinson's disease (PD), or simply Parkinson's, is a long-term degenerative disorder of the central nervous system that mainly affects the motor system. The symptoms usually emerge slowly, and as the disease worsens, non-motor symptoms becom ...

essential tremor Essential tremor (ET), also called benign tremor, familial tremor, and idiopathic tremor, is a medical condition characterized by involuntary rhythmic contractions and relaxations ( oscillations or twitching movements) of certain muscle groups in ...

. It was approved for use by the

Food and Drug Administration The United States Food and Drug Administration (FDA or US FDA) is a List of United States federal agencies, federal agency of the United States Department of Health and Human Services, Department of Health and Human Services. The FDA is respon ...

(FDA) on August 4, 1997. Installation is invasive, so it is typically only used when the tremors are incapacitating, and medication is ineffective. Typically, one or more electrodes are implanted in the

brain A brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as vision. It is the most complex organ in a v ...

, with subcutaneous leads to a neurostimulator, which may also be implanted. The electrodes stimulate the area of the

thalamus The thalamus (from Greek θάλαμος, "chamber") is a large mass of gray matter located in the dorsal part of the diencephalon (a division of the forebrain). Nerve fibers project out of the thalamus to the cerebral cortex in all directions, ...

, specifically the part of the brain that controls movement and muscle function. It is notable that the presence of thalamic stimulators significantly changes

ECG Electrocardiography is the process of producing an electrocardiogram (ECG or EKG), a recording of the heart's electrical activity. It is an electrogram of the heart which is a graph of voltage versus time of the electrical activity of the hear ...

patterns, and prevents the use of

MRI Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to form pictures of the anatomy and the physiological processes of the body. MRI scanners use strong magnetic fields, magnetic field gradients, and radio waves ...

. It is sometimes regarded as a better alternative to

pallidotomy Pallidotomy is a neurosurgical procedure. It is used to treat Parkinson's disease and some other conditions, often as an alternative to deep brain stimulation. It involves placing a tiny electrical probe in the globus pallidus, one of the basal g ...

thalamotomy Thalamotomy ( el, θάλαμος, thalamus, lit =chamber; el, τομή , tomē, lit=cut, slice) is a surgical procedure in which an opening is made into the thalamus to improve the overall brain function in patients. First introduced in the 1950 ...

because it is non-permanent. For optimal installation, the patient is awake during the procedure, and talks to the surgeon to find the best placement. Once in place, the device can be activated and deactivated, for improved effectiveness during the day. Risks arising from the operation are

infection An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable dise ...

stroke A stroke is a medical condition in which poor blood flow to the brain causes cell death. There are two main types of stroke: ischemic, due to lack of blood flow, and hemorrhagic, due to bleeding. Both cause parts of the brain to stop functionin ...

and

dysarthria Dysarthria is a speech sound disorder resulting from neurological injury of the motor component of the motor–speech system and is characterized by poor articulation of phonemes. In other words, it is a condition in which problems effectively ...

. A fictional treatment of the device, out decades before the device itself, can be found in the novel ''

The Terminal Man ''The Terminal Man'' is a novel by American writer Michael Crichton. It is his second novel under his own name and his twelfth overall, and is about the dangers of mind control. It was published in April 1972, and also serialized in ''Playboy' ...

''.

Sources

Differential electrocardiographic artifact from implanted thalamic stimulator

Washington University implanting brain device to control tremor

New device offers relief for patients with tremors
{{Central nervous system tests and procedures Implants (medicine) Neuroprosthetics