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Scope:

• this page provides information on the different causes of rest tremor Definition:
• rest tremor is present in a body part that is not voluntarily activated and is completely supported against gravity
• often caused by Parkinson's disease and other causes of parkinsonism
• however other causes of rest tremor should be considered Features of Parkinson's disease:
• typical unilateral onset of tremor in hand and occasionally a leg
• "pill rolling tremor" rare but a characteristic of Parkinson's disease
• rest tremor present in 70% of Parkinson's disease patients (practical tip - to induce rest tremor ask patient to count down from 10 out loud)
• Look for
  • facial or vocal impassivity
  • reduced arm swing on walking and shoulder shrug test (look for arm swing whilst shaking patient's shoulders)
  • cogwheel rigidity
  • bradykinesia
  • micrographia
  • postural instability
• refer to a person with expertise in Parkinson's disease prior to instigating medication Main causes:
• Parkinson's disease (see pathway)
• other causes of parkinsonism
• drug-induced tremor
• dystonic tremor syndromes
• severe essential tremor
• Holmes tremor (also termed rubral)
• psychogenic tremor
• Wilson's disease
• vascular parkinsonism - multiple system atrophy, progressive supranuclear palsy
• drug induced parkinsonism - phenothiazines, metoclopramide, hydrocephalus, encephalitis, toxicity (eg. manganese) Investigations:
• routine biochemistry, including thyroid function, liver function tests, calcium & phosphate
• Other possible investigations:
  • to rule out Wilson's diseasecopper studies if <50 years old at onset, but still consider if >50 years
  • dopamine transporter scan
  • consider genetic tests in appropriate cases
  • in young people (less than age 30 years) consider diagnostic studies to rule out Wilson's disease

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Features of Parkinson's disease

• typical unilateral onset of tremor in a hand and occasionally a leg
• "pill rolling tremor" rare but characteristic of Parkinson's disease
• rest tremor present in 70% of Parkinson's disease patients (practical tip - to induce rest tremor ask patient to count down from 10 out loud)
• Look for:
  • facial or vocal impassivity
  • reduced arm swing on walking and shoulder shrug test
  • cogwheel rigidity
  • bradykinesia (slow movements with decrement)
  • micrographia
  • postural instability
• refer to a person with expertise in Parkinson's disease prior to instigating medication 

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The following are clues to a psychogenic aetiology:

• history:
  • sudden onset, remissions or both
  • unusual combinations of rest, postural or intention tremors
  • somatization in past medical history
• consider medical causes for tremor with psychiatric illness (eg. Wilson's disease)
• Examination:
  • decreased tremor amplitude during distraction
  • variations in tremor frequency with distractions or voluntary movements of the other hand (entrainment)
  • co-activation sign of psychogenic tremor (tremor only present when arm is voluntarily stiffened)
  • appearance of additional and unrelated neurological signs
  • finger tremor is unusual in psychogenic tremor
  • simple reflex time studies
• consider other causes of tremor
• focus of treatment should be predominantly psychological

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• can be caused by numerous drugs or drug withdrawal
• usually presents as postural tremor, but rest and/or intention tremors may occur
• Commonly associated with:
  • alcohol
  • sympathomimetics
    • bronchodilators - â2 agonists
    • theophylline
    • caffeine
    • dopamine
    • epinephrine and norepinephrine
  • lithium
  • sodium valproate
  • antipsychotic medication
  • anti-emetics (metoclopramide, prochlorperazine)
  • tricyclic antidepressants
  • corticosteroids

1. any drug with a primary effect on the central nervous system can produce tremor as a side-effect 

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• Typically three tremor components are present: rest, postural tremorand intention tremor
• often severe. The action tremor severity is usually greater than that of the rest component
• slow (frequency <4.5Hz) irregular tremor
• tends to involve proximal (action tremor) and distal (rest tremor) muscles
• Holmes tremor has numerous causes including stroke, vascular malformations, tumours, head injury, toxoplasmosis, major tranquilizers, radiation)
• typically 2 weeks to 2 years delay from causal lesion to tremor onset
• lesions typically sited in midbrain or thalamus
• structural imaging (MRI scan) recommended
• dopamine transporter scan often abnormal
• multiple sclerosis is a rare cause of Holmes tremor 

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• multiple sclerosis (predominantly postural and intention tremor)
• peripheral neuropathy (predominantly postural and intention tremor)
• Wilson's disease
• hereditary ataxia