Tremor

What is a tremor?

A tremor is an involuntary shaking or trembling movement that a person cannot control. It most commonly affects the hands, but it can also involve the head, voice, legs, or other parts of the body. A tremor may occur on its own or be related to another medical condition.

Types of tremor

Tremors are grouped based on when they occur:

Rest tremor

  • Happens when the body part is relaxed, such as when sitting or lying down

  • Often improves or stops when you intentionally move the affected area

Action tremor

Occurs during voluntary movement. There are several forms:

  • Kinetic tremor – Appears when performing activities like writing or drinking; may worsen as you get closer to your target

  • Postural tremor – Happens when holding a position against gravity, such as keeping your arms outstretched

  • Isometric tremor – Occurs when muscles are contracting without movement, such as gripping or pushing against something

Functional tremor

  • May show features of both rest and action tremors

  • Does not have a clear structural or neurological cause

  • Often changes with distraction or when attention is directed elsewhere

What causes tremor?

The cause depends on the type of tremor:

Rest tremor

  • Most commonly linked to Parkinson’s disease

  • Can also be associated with other brain conditions or rare disorders such as Wilson disease

Action tremor

Often related to an exaggerated form of normal (physiologic) tremor. This can be triggered by:

  • Certain medications (for example, some used for asthma or mood disorders)

  • Caffeine, nicotine, or stimulant substances

  • Stress, anxiety, or strong emotions

  • Fatigue or muscle overuse

  • Alcohol withdrawal

  • Fever

  • Overactive thyroid function

When these triggers are addressed, the tremor often improves or resolves.

What is essential tremor?

Essential tremor is a common neurological condition that causes action tremor without an identifiable external trigger.

  • It often runs in families

  • Tremor typically occurs when holding the arms out or performing tasks

  • Common activities affected include writing, drinking, or using utensils

  • It can also involve the head, causing a “yes-yes” or “no-no” shaking pattern

How is tremor evaluated?

There is no single test to diagnose the cause of tremor. Assessment usually includes:

  • A detailed history of symptoms

  • Physical and neurological examination

In some cases, additional tests such as blood work or brain imaging may be done to rule out underlying conditions.

How is tremor treated?

Treatment depends on the cause and severity:

  • Addressing underlying conditions (such as thyroid problems or medication side effects) can reduce tremor

  • Medications may be prescribed to help control symptoms

  • Lifestyle adjustments (reducing caffeine, managing stress) can be helpful

  • Advanced therapies, including procedures like deep brain stimulation, may be considered for severe cases that do not respond to medication

If tremor is affecting daily activities, discussing treatment options with a healthcare provider can help tailor an approach to your specific situation.