Characteristics may include a rhythmic shaking in the hands, arms, head, legs, or trunk; shaky voice; difficulty writing or drawing; or problems holding and controlling utensils, such as a fork. Some tremors may be triggered by or become exaggerated during times of stress or strong emotion, when the individual is physically exhausted, or during certain postures or movements.
Tremor may occur at any age but is most common in middle-aged and older persons. It may be occasional, temporary, or occur intermittently. Tremor affects men and women equally.
A useful way to understand and describe tremors is to define them according to the following types. Resting or static tremor occurs when the muscle is relaxed and the limb is fully supported against gravity, such as when the hands are lying on the lap. It may be seen as a shaking of the limb, even when the person is at rest. This type of tremor is often seen in patients with Parkinson’s disease. An action tremor occurs during any type of movement of an affected body part. There are several subclassifications of action tremor. Postural tremor occurs when the person maintains a position against gravity, such as holding the arms outstretched. Kinetic (or intention) tremor occurs during purposeful voluntary movement, such as touching a finger to one’s nose during a medical exam. Task-specific tremor appears when performing highly skilled, goal-oriented tasks such as handwriting or speaking. Isometric tremor occurs during a voluntary muscle contraction that is not accompanied by any movement.