Overview of the Types of Tremors

In order to determine the cause of a tremor, and hence, the best treatment options, it's essential to know the type of tremor you have. Let's take a look at how tremors are classified into different categories, as well as some of the terminology which is used to describe the characteristics of different tremors.

Evaluation of Tremors

When evaluating someone who has a tremor such as finger tremors or hand tremors, a neurologist will ask questions about what makes the tremor better or worse, whether anyone in the family has had tremors and any other symptoms which might provide clues as to the cause.

Using this history, and after doing a physical examination, neurologists will use all the information they’ve gathered to put the tremor into one of the several categories. Each category is associated with different disease types, and therefore also associated with different types of treatments. 

To make these categories easier to understand, let's first clear up some of the terminologies you may here.

Describing Tremors

There are several terms which are used to describe tremors. Many of these are based on whether actions (movement) make the tremor worse.

• Resting tremor: A tremor which is present at rest
• Action tremor: A tremor which appears when a body part is being moved
• Intention tremor: An intention tremor also occurs with movement but worsens when you get close to a target
• Kinetic tremor: A tremor which occurs during voluntary movement
• Task-specific tremors: Tremors which occur only with specific actions
• Isometric tremor: A tremor which occurs when a body part is not moving but the muscles are tensed. The example often used is having your arms shake during push-ups when your position is held.
• Postural tremor: A tremor which occurs when a body part is held against gravity (holding your arms straight out in front of you)

Classification of Tremors Into Categories

Having your type of tremor classified correctly can help you obtain the right type of treatment for your condition. The tremor classifications are as follows:

Physiologic Tremor

Everyone has a 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 an “enhanced physiological tremor”) due to anxiety, fatigue, stimulants like caffeine, fever, alcohol withdrawal, low blood sugar, some medications, and more. Enhanced physiological tremor goes away when the underlying cause is corrected.

Essential Tremor

Essential tremor affects up to six percent of the population. This tremor progresses very slowly and usually increases with age, affecting in particular people over the age of 60. 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. Since the tremor occurs when you are doing things, it can result in annoying problems such as spilling coffee and shaving injuries.

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 (a beta-blocker) 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

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.

If the cause of a Parkinsonian tremor is Parkinson’s disease, it may respond well to levodopa or other dopaminergic medications. Other possibilities include amantadine and anticholinergic drugs.

Dystonic Tremor

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).

The treatment of dystonia, as well as the associated tremor, is commonly done with injections of attenuated botulinum toxin. Clonazepam or anticholinergic medications may also be helpful.

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 Tremor

In 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.

Psychogenic Tremor

Like other psychogenic disorders (psychosomatic disorders), psychogenic tremor is a diagnosis of exclusion, meaning that other forms of tremor must be excluded. Psychogenic tremor may also be referred to as functional tremor. 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.

Seeking Treatment

In all cases of tremor, including psychogenic tremor, the primary focus should be on treating any underlying disorder as much as possible, rather than simply treating the symptom (the tremor).

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.