Common Tremors
Parkinsonian Tremor
- Asymmetric, rest tremor
- It typically begins on one side before the other and predominates on that side throughout the progression of the illness and it is most prominent at rest and resolves with action.
- Typically a rest tremor with pill-rolling circular motion of the index finger and thumb.
- Resolves with action.
- Parkinson's tremor is high amplitude but slow frequency (4 – 6 Hz).
Essential Tremor
- Symmetric, kinetic tremor.
- Effects both sides equally (although there is still often some asymmetry) and it worsens with particular actions (eg, writing or eating).
- Action (eg, bringing a spoonful of soup towards the mouth) amplifies the tremor.
- Alcohol characteristically dampens the tremor.
- As a major differentiator from parkinsonism, muscle tone is normal in essential tremor (it rigid with parkinsonism).
- Essential tremor is mid amplitude and is also mid frequency (5 – 8 Hz).
Enhanced Physiologic Tremor
- Symmetric and invariable.
- It effects both sides equally and does not change throughout rest and activity.
- On exam, it's notable that on finger to nose testing, the tremor is the same throughout the action: there is no intentional component. Essential tremor, instead, will typically accentuate as the patient reaches the tip of the examiner's finger.
- Stress and caffeine accentuate the tremor.
- Enhanced physiologic tremor is low amplitude but high frequency (8 – 12 Hz).