Tremor

Frequency
1. Slow Tremor: 3-5 Hz (e.g. Rest Tremor)
2. Intermediate: 5-8 Hz (e.g. Isometric Tremor)
3. Rapid Tremor: 9-12 Hz (e.g. Postural Tremor)
Amplitude
1. Fine Tremor: Barely noticeable (e.g. Postural Tremor)
2. Medium
3. Coarse Tremor: Large displacement (e.g. Rest Tremor)

Background
1. Tremor causes cross-over categories (rest, postural, action)
2. Many Postural Tremors also have Rest Tremor and Action Tremor features
Rest Tremor
1. Most cases are due to Parkinsonism (although severe Essential Tremor can mimic this)
2. Patient attempts to maintain body position at rest (despite support against gravity)
3. Provoked by stress or distraction (e.g. counting backwards) or moving another body part (e.g. walking)
4. Rest Tremor decreases with voluntary movement
Postural Tremor
1. Patient attempts to maintain Posture against gravity (stretch hands out in front of them)
2. Essential Tremor
3. Physiologic Tremor or Enhanced Physiologic Tremor
4. Drug-Induced Tremor
5. Other causes
Action Tremor
1. Isometric Tremor
  1. Muscle Contraction against rigid item (e.g. grasping with fist)
2. Kinetic Tremor
  1. Occurs with any form of voluntary movement
3. Intention Tremor (subtype of Kinetic Tremor)
  1. Tremor amplifies as target is reached
  2. Exercise high index of suspicion for cerbellar lesion (see Cerebellar Tremor)
4. Task-specific tremor (subtype of Kinetic Tremor)
  1. Tremor on performing highly skilled activity (e.g. writing, speaking, playing music)

Characterize Tremor
1. Record part of body with Tremor
2. Provocative and palliative factors
3. Tremor frequency (fast or slow Tremor)
4. Tremor amplitude (coarse or fine Tremor)
Observe with hands resting in lap (Rest Tremor)
Observe writing or drinking (Action Tremor)
Perform Finger-Nose-Finger Test (Intention Tremor)
Draw a spiral (Archimedes Spiral in Essential Tremor)
Focus exam based on Tremor type

Step 1: Enhanced Physiologic Tremor
1. Consider Thyroid Stimulating Hormone, Serum Glucose, Liver Function Tests
2. Manage by avoiding provocative factors
Step 2: Drug-Induced Tremor
1. Eliminate or reduce dose of offending agent
Step 3: Psychogenic Tremor (e.g. relieved with distraction)
1. See Psychogenic Tremor for management
Step 4a: Patient under age 40
1. Wilson's Disease
  1. Low serum ceruloplasmin and high 24 hour urinary Copper
2. Associated Neurologic findings
  1. Evaluate with MRI Brain and labs above
3. Essential Tremor
  1. Diagnosis of exclusion if other causes excluded
  2. Trial on Beta Blocker
Step 4b: Patient over age 40
1. Rest Tremor
  1. Parkinsonism likely
  2. If rigidity, Bradykinesia or postural instability then trial on Parkinsonism treatment
2. Action Tremor
  1. Consider Alcohol Tremor
  2. Postural Tremor
    1. Essential Tremor
  3. Intention Tremor or Cerebellar Tremor
    1. Obtain MRI Brain
    2. Evaluate for Multiple Sclerosis, Cerebrovascular Accident, Brain Tumor

International Tremor Foundation
1. Overland Park, Kansas
2. Phone: (913) 341-3880
See Parkinson's Disease Resources

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