Tremors are abnormal movements of the body that occur because of conditions affecting the nervous system. Some tremors occur at rest and become less apparent with activity. They are referred to as rest tremors. The classic rest tremor is from Parkinson's disease. Some tremors are most apparent as the extremity is lifted against gravity and not moving toward a target (for example, from hyperthyroidism, familial, and stress fear). These tremors are referred to as positional or postural tremors. Some tremors are more prominent with movement actions toward a target and are referred to as intention tremors. This is what occurs with disease or damage to the cerebellum of the brain. A neurologist is a specialist expert in evaluating tremors.