Essential Tremor
Summary
Essential tremor (ET) is the most common movement disorder, affecting 0.5-5% of the population. It is characterised by a bilateral, symmetric postural and kinetic tremor, typically affecting the hands. Unlike Parkinson's disease, essential tremor is predominantly an action/postural tremor (not resting) and is not associated with rigidity or bradykinesia. It has a strong genetic component (autosomal dominant in ~50%). The tremor frequency is typically 4-12 Hz and is characteristically improved by alcohol and worsened by anxiety. First-line treatment is propranolol or primidone; deep brain stimulation (DBS) is reserved for severe refractory cases.
Key Facts
- Prevalence: 0.5-5% of general population; Increases with age
- Inheritance: Autosomal dominant in ~50%
- Tremor type: Postural and kinetic (action tremor); NOT resting
- Frequency: 4-12 Hz (typically 5-8 Hz)
- Improvement: Alcohol (small amounts)
- Worsening: Anxiety, caffeine, fatigue
- Treatment: Propranolol; Primidone; DBS for severe cases
Clinical Pearls
"Action Tremor = Essential Tremor; Resting Tremor = Parkinson's": Essential tremor is present during voluntary movement (holding a cup, finger-nose test). Parkinson's tremor occurs at rest and decreases with action.
"Alcohol Improves Essential Tremor": A classic feature. Patients often notice improvement with small amounts of alcohol. This can help distinguish from other tremors but is not diagnostic.
"Head Tremor Often Accompanies Hand Tremor": Essential tremor may involve the head ("yes-yes" or "no-no" movement), voice, and chin, in addition to hands.
"Propranolol First, Primidone Second": Propranolol is first-line; Primidone is an alternative. Both reduce tremor amplitude by 40-50%.
"DBS Works for Severe Essential Tremor": Deep brain stimulation of the ventral intermediate nucleus (VIM) of the thalamus is highly effective for refractory essential tremor.
Why This Matters Clinically
Essential tremor is benign but can significantly impact quality of life, particularly handwriting, eating, and social activities. Distinguishing it from Parkinson's disease is clinically important.[1,2]
Incidence & Prevalence
| Parameter | Data |
|---|---|
| Prevalence | 0.5-5% of population; Up to 20% in elderly |
| Onset | Bimodal: Young adulthood and >60 years |
| Family history | Positive in ~50% (autosomal dominant) |
Risk Factors
| Factor | Notes |
|---|---|
| Age | Prevalence increases with age |
| Family history | Strong genetic component |
Mechanism
| Feature | Details |
|---|---|
| Central oscillator | Likely involves olivocerebellar circuit |
| Cerebellum | Abnormal cerebellar activity |
| Thalamus | VIM nucleus involved (target for DBS) |
| Genetic | LINGO1 and other genes implicated |
Tremor Characteristics
| Feature | Essential Tremor | Parkinson's Disease |
|---|---|---|
| Type | Postural and kinetic (action) | Resting |
| Symmetry | Bilateral, symmetric | Asymmetric |
| Frequency | 4-12 Hz (typically 5-8 Hz) | 4-6 Hz |
| Hands | Yes | Yes |
| Head | Common ("yes-yes" / "no-no") | Rare |
| Voice | May be affected | Rare |
| Improvement | Alcohol | Rest |
| Worsening | Anxiety, caffeine, fatigue | Action |
| Associated features | None | Rigidity, Bradykinesia |
Symptoms
| Symptom | Notes |
|---|---|
| Hand tremor | Most common; Bilateral |
| Head tremor | Nodding or shaking motion |
| Voice tremor | Tremulous voice |
| Difficulty with fine motor tasks | Writing, eating, drinking |
Signs
| Sign | Notes |
|---|---|
| Postural tremor | Hands outstretched |
| Kinetic tremor | Finger-nose test — tremor increases at target (no true ataxia) |
| No rigidity | Important to exclude Parkinson's |
| No bradykinesia | Normal speed of movement |
Tremor Assessment
| Test | Finding |
|---|---|
| Arms outstretched | Postural tremor visible |
| Finger-nose test | Kinetic tremor; Worse near target but no true dysmetria |
| Spiral drawing | Tremulous; Large, irregular |
| Pouring water | Accentuates tremor |
| Handwriting sample | Tremulous; Large script (vs micrographia in PD) |
Exclude Parkinson's Disease
| Feature | Check |
|---|---|
| Resting tremor | Absent in ET |
| Rigidity | Absent in ET |
| Bradykinesia | Absent in ET |
| Postural instability | Absent in ET |
Clinical Diagnosis
Essential tremor is a clinical diagnosis. Investigations are only needed if:
- Diagnosis uncertain
- Features suggestive of secondary cause or Parkinson's disease
| Investigation | Purpose |
|---|---|
| TFTs | Exclude hyperthyroidism |
| Drug history | Beta-agonists, valproate, lithium, caffeine |
| DaTscan | If Parkinson's suspected (reduced dopamine transporter uptake in PD) |
Management Algorithm
ESSENTIAL TREMOR MANAGEMENT
↓
┌───────────────────────────────────────────────────────────┐
│ CONSERVATIVE │
├───────────────────────────────────────────────────────────┤
│ ➤ Patient education (benign condition) │
│ ➤ Avoid caffeine │
│ ➤ Weighted utensils and writing aids │
│ ➤ Stress management │
└───────────────────────────────────────────────────────────┘
↓
┌───────────────────────────────────────────────────────────┐
│ FIRST-LINE PHARMACOTHERAPY │
├───────────────────────────────────────────────────────────┤
│ ➤ Propranolol (beta-blocker): │
│ • 40-320 mg daily in divided doses │
│ • Reduces tremor amplitude by ~50% │
│ • Contraindicated: Asthma, bradycardia, heart block │
│ │
│ OR │
│ ➤ Primidone (anticonvulsant): │
│ • Start 25-50 mg at night; Titrate to 250-750 mg │
│ • Sedation initially; Start low │
│ │
│ ➤ May combine both if monotherapy insufficient │
└───────────────────────────────────────────────────────────┘
↓
┌───────────────────────────────────────────────────────────┐
│ SECOND-LINE OPTIONS │
├───────────────────────────────────────────────────────────┤
│ ➤ Topiramate │
│ ➤ Gabapentin │
│ ➤ Botulinum toxin (head/voice tremor) │
└───────────────────────────────────────────────────────────┘
↓
┌───────────────────────────────────────────────────────────┐
│ SURGICAL (REFRACTORY) │
├───────────────────────────────────────────────────────────┤
│ ➤ Deep Brain Stimulation (DBS) of VIM thalamus │
│ ➤ Focused Ultrasound Thalamotomy │
│ ➤ For severe, medication-refractory cases │
│ ➤ Very effective (up to 80% improvement) │
└───────────────────────────────────────────────────────────┘
| Complication | Notes |
|---|---|
| Functional impairment | Eating, drinking, writing |
| Social embarrassment | Significant QoL impact |
| Medication side effects | Fatigue (propranolol); Sedation (primidone) |
| Factor | Outcome |
|---|---|
| Progressive | Slowly progressive over years |
| Life expectancy | Normal |
| Treatment response | ~50% improvement with propranolol/primidone |
| DBS | Highly effective for refractory cases |
Key Guidelines
| Guideline | Organisation | Year | Key Points |
|---|---|---|---|
| NICE CKS Tremor | NICE | 2021 | Diagnosis and management |
What is essential tremor?
Essential tremor is a condition that causes shaking, usually in the hands, when you're trying to do things (like holding a cup or writing). It's very common and is not related to any serious illness.
What are the symptoms?
- Shaking of the hands when holding them out or using them
- Head shaking (like nodding "yes" or shaking "no")
- Shaky voice
- Getting worse with stress or caffeine
How is it different from Parkinson's?
In essential tremor, the shaking happens when you're moving or holding your hands up. In Parkinson's, the shaking happens at rest and stops when you move. Parkinson's also causes stiffness and slowness, which essential tremor doesn't.
How is it treated?
- Avoiding caffeine
- Tablets like propranolol (a beta-blocker) or primidone
- For severe cases, surgery (deep brain stimulation) can help
Is it serious?
Essential tremor is not dangerous, but it can be annoying and affect daily activities. Many people find treatment helpful.
- Louis ED. Essential tremor. Lancet Neurol. 2005;4(2):100-110. PMID: 15664542
High-Yield Exam Topics
| Topic | Key Points |
|---|---|
| Tremor type | Postural and kinetic (action); NOT resting |
| Symmetry | Bilateral, symmetric |
| Improvement | Alcohol (small amounts) |
| Exclude Parkinson's | No rigidity, bradykinesia, resting tremor |
| Treatment | Propranolol or Primidone first-line |
| DBS | VIM thalamus for refractory cases |
Sample Viva Question
Q: How do you differentiate essential tremor from Parkinson's disease tremor?
Model Answer:
| Feature | Essential Tremor | Parkinson's Disease |
|---|---|---|
| Tremor type | Postural and kinetic (action tremor) | Resting tremor |
| Symmetry | Bilateral, symmetric | Asymmetric |
| Frequency | 5-8 Hz | 4-6 Hz |
| Head/voice | Often involved | Rarely |
| Improvement | Alcohol | Rest |
| Associated features | None | Rigidity, Bradykinesia, Postural instability |
| DaTscan | Normal | Abnormal (reduced uptake) |
Essential tremor is benign; Parkinson's is progressive neurodegenerative.
Last Reviewed: 2025-12-24 | MedVellum Editorial Team