Tremor

Tremor refers to involuntary and rhythmic movement of a body part, usually the hands or head. Tremor is physiological in some cases, and pathological in others. Physiological tremor can occur in stress, sympathetic activation, hyperthyroidism, caffeine overuse, and alcohol withdrawal.

The most important examination for tremor is careful observation. Observe whether the tremor improves by distraction.

Classification

• Rest tremor = tremor occurs when resting the body part
  • Parkinsonism
  • Neuroleptic drugs
• Action tremor = tremor occurs during active movement
  • Simple kinetic tremor = tremor is constant throughout the movement
  • Intention tremor = increasing tremor when the hand reaches the target
  • Task-specific tremor = tremor occurs during specific task
    • Writing tremor
• Postural tremor = tremor which occurs when arms are held out against gravity
  • Physiological tremor
  • Essential tremor
• Psychogenic tremor = tremor due to psychiatric disease, improve when patient is distracted
• Flapping tremor (asterixis) = flapping of the hands, occurs in hepatic encephalopathy

Essential tremor

Essential tremor is a hereditary (autosomal dominant) disorder causing a fine tremor, usually of the hands. Tremor of vocal cord can cause a “shaky” voice. The tremor worsens with stress, fatigue, caffeine, and it improves with alcohol. Propranolol can be used to improve the symptoms.

Rest tremor

Rest tremor is typical for parkinsonism. Voluntary movement decreases the tremor. In Parkinson disease, the tremor usually begins unilaterally, eventually affecting the contralateral side as well as the disease progresses.

A typical form of rest tremor in Parkinson disease is the "pill-rolling" tremor, where a tremor of the distal muscles of the hand results in movement as if rolling a pill between the thumb and index finger.

Intention tremor

Intention tremor is typical for cerebellar injury, usually due to cerebellar stroke, traumatic brain injury, multiple sclerosis, or chronic alcohol abuse. As such, it's often called "cerebellar tremor".

The tremor is usually large in amplitude and can be difficult to distinguish from ataxia.