RAD 1601: Pilot Trial of Frameless Virtual Cone Stereotactic Radiosurgical Thalamotomy for Intractable Tremor and Advanced Functional Connectivity Parcellation of the Thalamus

Per the National Institute of Neurological Disorders and Stroke, tremor is an involuntary, rhythmic muscle contraction leading to shaking movements in one or more parts of the body. It is a common movement disorder that most often affects the upper extremities but can also occur in the head, vocal cords, torso, and lower extremities. Tremor may be intermittent or constant. It can be present at rest, during action, or mixed between rest and action.

Tremor can occur at any age but it is most common among middle-aged and older adults; once it occurs, it often progresses over time. This disorder shows no gender predilection. Although tremor is not life threatening, it can be severely disabling, making it difficult or even impossible to perform work and daily life tasks.

Deep parts of the brain that control movements appear to be involved in tremor development. However, most types of tremor have no actual known cause. There are some forms that appear to be inherited and run in families. There are more than 20 types of tremor. Tremor can occur on its own (such as essential tremor (ET) or be associated with other neurological disorders, such as Parkinson's disease (PD).

Tremor is a common symptom of Parkinson's disease. The classification of patients with Parkinson's disease into tremor-dominant and non-tremor subtypes is well established. The pathophysiology of tremor in patients with tremor-dominant Parkinson's disease (TDPD) may be distinct from other their other symptoms, such as bradykinesia, rigidity, and gait and balance symptoms. Importantly, tremor in PD responds less well or can even be highly resistant to dopaminergic treatment than bradykinesia and rigidity. Therefore other treatment strategies may need to be considered.

Essential Tremor (ET) is a common neurologic condition characterized by a tremor that can occur either with posture or action. In the US, there are reported to be as many as 10 million people with essential tremor. A significant subset of patients experience persistent disability and disruption on activities of daily living from tremor and require intervention.