found: NIH, National Institute of Neurological Disorders and Stroke, viewed Nov. 10, 2022:Tremor Fact Sheet (Tremor is an involuntary, rhythmic muscle contraction leading to shaking movements in one or more parts of the body." movement disorder; may affect many different parts of the body; intermittent or constant; many different causes, including many neurological disorders; categories: resting tremor or action tremor; action tremors include postural, kinetic, intention, task-specific, or isometric tremor; many different specific types)