By the way, doctor: Tremors
Q. I am curious about tremors in adults. I know that people with Parkinson's disease get them, but I am not sure about other conditions.
A. Our muscles are programmed for various kinds of rapid alternating movements, from the hands of a drummer to shivering when we get a chill. In fact, there's a background low-amplitude oscillation to all of our muscle movements called physiological tremor that's perfectly normal. Some conditions, such as overactive thyroid, exaggerate this tremor so it becomes obvious — for instance, when the person holds out a hand. Correction of the thyroid condition eliminates this kind of tremor.
The two most notorious kinds of tremor occur in conditions called essential tremor and parkinsonism.