Essential Tremor

Epidemiology and Progression

• Essential tremor is the most common movement disorder after restless leg syndrome, with a prevalence in the United States estimated between 0.3% and 5.55% 1
• Essential tremor is typically progressive, with symptoms worsening over time 1

Impact and Associations

• Essential tremor can significantly interfere with quality of life, functional activities, mood, and socialization, although it does not shorten life expectancy 1
• There is an association between essential tremor and an increased risk of other neurodegenerative conditions, including Alzheimer's disease and Parkinson's disease 1

Related Conditions

• Parkinsonian syndromes, including Parkinson's disease, progressive supranuclear palsy, multiple system atrophy, and corticobasal degeneration, are related conditions 2

Diagnosis and Classification

• Classification of essential tremor by activation condition includes postural tremors (4-8 Hz), kinetic tremors, and rest tremors (4-6 Hz), as recommended by the International Parkinson and Movement Disorder Society 3
• Laboratory testing is used to rule out secondary causes, including thyroid function tests, liver function tests, basic metabolic panel, and HbA1c, with consideration of copper studies if Wilson's disease is suspected 4, 5

Management and Treatment

• The American Academy of Neurology recommends a comprehensive approach to managing tremors, including assessing tremor severity and impact on quality of life, with treatment initiated when tremor causes functional disability 1
• Non-pharmacological treatments recommended by the American Academy of Neurology include superimposing alternative, voluntary rhythms, relaxing muscles to prevent cocontraction, and using gross movements and sensory grounding 6
• First-line pharmacological treatments for essential tremor include propranolol, primidone, and topiramate, which can improve tremor in approximately 50% of patients, according to the American Academy of Neurology 1, 4
• The following treatment options are available for essential tremor:

• The American Heart Association recommends propranolol as the first-line beta-blocker treatment for tremor management, while carvedilol has limited evidence supporting its use for tremors 7
• Surgical options, including MR-guided focused ultrasound thalamotomy, deep brain stimulation (DBS), and radiofrequency thalamotomy, may be considered for patients with significant functional disability despite optimal medical therapy, as recommended by the American Academy of Neurology 1
• Patient selection criteria for MRgFUS thalamotomy include medically refractory essential tremor with significant functional impairments, patients who can provide informed consent, and anticipated significant functional improvement with unilateral tremor treatment, as supported by the American Academy of Neurology and the International Parkinson and Movement Disorder Society 1

Surgical Treatment

• MR-guided focused ultrasound thalamotomy is currently indicated only for unilateral treatment and is contraindicated in patients with MRI contraindications or skull density ratio <0.40, with a complication rate of 4.4% compared to 11.8% for radiofrequency thalamotomy and 21.1% for DBS 1
• Deep brain stimulation (DBS) of the thalamus provides adequate tremor control in approximately 90% of patients and is preferred for bilateral procedures due to fewer complications than bilateral ablative procedures, but has a higher complication rate than MRgFUS 1