Anticonvulsant, anti-seizure medication – A class of pharmaceutical drugs used to help regulate the way nerve impulses travel along nerve cells. Though originally developed to help control epileptic seizures, in some ET patients such medications as primidone or gabapentin may stabilize abnormal nerve transmissions that cause tremors. Side effects include drowsiness and nausea, which usually disappear over a short period.

Beta blockers – A type of drug first developed to help control blood pressure. In this class, propranolol is most often prescribed to help reduce tremors. For ET patients with asthma or certain heart conditions, beta blockers may not be an option. Side effects include possible tiredness, lightheadedness, or heart problems.

Cerebellum – A part of the brain located behind the top part of the brain. It is believed that most ET begins here, though other parts of the brain may also be involved. The cerebellum does not initiate movement but plays an important role in coordinating and timing movement. If malfunctioning messages from the cerebellum are transmitted to the thalamus, it will forward abnormal signals to the muscles, resulting in tremors.

Deep Brain Stimulation (DBS) – A surgical procedure involving the use of direct electrical stimulation to interrupt abnormal timing signals from the thalamus to muscles. First, a small battery pack similar to a heart pacemaker is implanted under the skin in the chest. Next, electrodes are implanted through the skull into the thalamus in the brain. Finally, the electrodes are connected to the battery pack. DBT is an alternative to thalamotomy. Because of the brain surgery (incision and drilling into the skull) patients usually spend 1-2 nights in the hospital until they can walk, talk, and are pain free.

Focused Ultrasound (FUS) – Ultrasound, or sonic energy, consists of harmless sound waves at a frequency humans can’t hear. Since ultrasound passes harmless through skin and other tissues, it is primarily used for medical imaging. More recently, scientists have discovered that when a different frequency of ultrasound is precisely focused on a target in the body from many different directions at the same time, where the beams converge (meet), they create enough heat to destroy the target. For medical purposes, powerful imaging such as MRI is used to plan, guide and monitor FUS procedures.

Gabapentin – See Anticonvulsant

Magnetic Resonance Imaging – A technology for conducting detailed, high resolution scans of soft tissue, bone and other structures by harnessing a powerful magnetic field and pulsing radio waves through it. The resulting signals are picked up by a receiver and converted by special software into highly accurate, real-time images on a monitor. MRI scans are used to plan, guide and monitor noninvasive treatments using FUS in real time.

MRI-guided Focused Ultrasound (MRgFUS) – A treatment process that uses beams of Focused Ultrasound under real-time MRI guidance. MRgFUS can be used to perform an image-guided, noninvasive thalamotomy to treat Essential Tremor.

Neuravive – The manufacturer’s brand name for MRgFUS offered by the Sperling Medical Group.

Primidone – see Anticonvulsant

Propranolol – see Beta blockers

Radiofrequency thalamotomy – An invasive type of thalamotomy that destroys the VIM in the thalamus by heat from an electrical current generated at the tip of a probe.

Thalamotomy – A surgical brain treatment to interrupt pathways of abnormal nerve transmission in order to control tremors. It can be performed invasively (requires an incision in the scalp, a hole drilled in the skull, and the image-guided insertion of instruments or probes through the brain into the thalamus) or noninvasively (using MRgFUS).

Thalamus – A structure at the center of the brain composed of many different sub-centers (nuclei), each of which has a specific function. It acts as a relay to receive and direct nerve pathway messages, and is involved in motor (movement) functions. Today’s powerful imaging such as MRI can successfully map the individual nuclei, making it possible to treat conditions like ET that are mediated by the thalamus.

Ventral Intermediate Nucleus – A sub-center or nucleus within the thalamus that receives nerve messages from the cerebellum and relays them in order to help plan and coordinate movement. The Neuravive MRgFUS treatment for Essential Tremor precisely targets and destroys the VIM in order to interrupt the abnormal brain messages that cause ET.