When evaluating someone who has a tremor, neurologists will ask questions about what makes the tremor better or worse, whether anyone in the family has had tremor, and also ask about other symptoms that could give clues about the cause. After doing a physical examination, neurologists will use all the information they’ve gathered to put the tremor into one of several categories. Each category is associated with different disease types, and therefore also associated with different types of treatments.
Everyone has physiologic tremor, although it usually isn’t very noticeable. This is the tremor you may have noticed when you hold your hand out with fingers extended. It may become more noticeable (thereby becoming “enhanced physiological tremor”) due to anxiety, fatigue, stimulants like caffeine, fever, alcohol withdrawal, low blood sugar and more. Enhanced physiological tremor goes away when the underlying cause is corrected.
Essential tremor is a very common problem. This tremor progresses very slowly, and usually affects people after the age of 40. The hands are usually most affected. The tremor is an action tremor, meaning that it is most prominent whenever someone tries to use their hands to do something. The tremor also worsens with emotions, stress, or physical exhaustion, and sometimes improves after drinking a little alcohol. Essential tremor often runs in families, but no single gene has been found to explain the disorder. The part of the brain involved with essential tremor is uncertain, although some believe that the cerebellum or thalamus are probably involved.
It is not always necessary to treat essential tremor with medication. If a medication is used, propranolol and primidone are the most widely accepted treatments. Of course, no medication is without possible side effects, and the potential risks must be considered against the possible benefits of taking any medication.
Parkinsonian tremor is most noticeable when the hands are at rest. This has been described as a “pill-rolling” tremor, since it classically looks as if a pill is being rolled between the thumb and fingers of the hand. The legs, chin and body can also be involved. Like other tremors, Parkinsonian tremor can be worsened by stress. Despite the name, Parkinsonian tremor is not always caused by Parkinson’s disease, but can also be caused by other neurodegenerative disorders, drugs, infections and toxins. If the tremor is caused by Parkinson’s disease, it normally starts more on one side of the body than the other.
Dystonia is a movement disorder in which muscles contract involuntarily, causing abnormal postures that may be painful. The tremor may represent an attempt to correct the abnormal muscle contraction that repeatedly fails. Unlike other forms of tremor, moving or holding the body in a specific fashion may worsen dystonic tremor. The tremor may improve with rest or by touching part of the body (usually but not always the part that is affected by the dystonia).
Cerebellar and Rubral Tremors
The classic cerebellar tremor is an intention tremor, meaning that it is most prominent during an act of coordination such as pushing a button. The tremor will be worst as the finger is just about to meet its target. As the name suggests, cerebellar tremor is caused by damage to the cerebellum or its pathways in the brainstem. Rubral tremor is a less common subtype of cerebellar tremor. It is slow, large in amplitude, and can occur in all directions. Unfortunately, there are no easy treatments for cerebellar tremor. If possible, the underlying cause should be addressed.
Orthostatic TremorIn orthostatic tremor, the legs and trunk start trembling soon after standing. Someone with orthostatic tremor may not notice a tremor so much as unsteadiness after standing up. It improves as soon as someone sits down. Treatment can be with either clonazepam or primidone.
Like other psychogenic disorders, psychogenic tremor is a diagnosis of exclusion, meaning that other forms of tremor must be excluded. Clues that a tremor is psychogenic include the tremor disappearing when someone is distracted, the tremor suddenly appearing after a stressful incident, or frequent and otherwise unexplainable changes in the body part affected by the tremor. Other symptoms of conversion disorder or psychiatric illness can also be helpful in diagnosing psychogenic tremor.
In all cases of tremor, including psychogenic tremor, the primary focus should be on treating any underlying disorder as much as possible. Physical therapy can be helpful for tremor as well. In cases where medical and physical therapies have been insufficient, and the tremor remains truly debilitating, more invasive options, such as brain surgery or deep brain stimulation, can be considered. As always, treatment options should be thoroughly discussed with your care provider.
Braunwald E, Fauci ES, et al. Harrison's Principles of Internal Medicine. 16th ed. 2005
AH Ropper, Samuels MA. Adams and Victor's Principles of Neurology, 9th ed: The McGraw-Hill Companies, Inc., 2009