The term "tremor" is used to describe the uncontrollable shaking associated with essential tremor (ET), but that's a symptom that can be caused by a multitude of different factors and diseases -- including Parkinson's disease, multiple sclerosis, fatigue after exercise, extreme emotional distress, brain tumors, some prescription drugs, metabolic abnormalities, and alcohol or drug withdrawal.
Tremors can be classified as those that occur when:
A gun is fired from somewhere off-screen directly at actor Angela Lansbury,
who sits calmly, speaking into the camera. As the slow-motion bullet travels
straight toward her, she explains this is how amyotrophic lateral sclerosis
(ALS), otherwise known as Lou Gehrig’s disease, attacks your body. “You know
what’s coming, but you can’t do anything about it.”
Then, after an appeal to the audience to support global research efforts,
she stands and walks boldly off-screen, dodging the bullet just...