Differentiating Essential Tremor from Intentional Tremor

Characteristics and Differentiation

Essential tremor is a progressive neurological syndrome with a prevalence in the US between 0.3% and 5.55%, primarily presenting as bilateral action tremor of the arms and hands, significantly interfering with quality of life, functional activities, mood, and socialization, and can cause greater impairment than Parkinson's disease in activities like writing, eating, drinking, and reading 1
Intentional tremor is characterized by coarse, irregular tremor that becomes more pronounced during goal-directed movements, often has a "wing-beating" appearance, and is frequently accompanied by dysarthria and ataxic gait, primarily associated with cerebellar pathology or its connections 2

The American Academy of Neurology recommends first-line pharmacological treatment for essential tremor, including propranolol (80-240 mg/day) and primidone, with treatment initiation only when tremor interferes with function or quality of life 1, 3
Intentional tremor is more challenging to treat pharmacologically than essential tremor, but may respond to certain medications, and physical therapy and occupational therapy with adaptive devices may help improve function 2
Surgical options for refractory cases include magnetic resonance-guided focused ultrasound (MRgFUS) thalamotomy, deep brain stimulation (DBS), and radiofrequency thalamotomy, with MRgFUS showing sustained tremor improvement of 56% at 2 years 1, 3, 4
MRgFUS thalamotomy has a lower complication rate (4.4%) compared to radiofrequency thalamotomy (11.8%) and DBS (21.1%), but is contraindicated in patients who cannot undergo MRI, have skull density ratio <0.40, or need bilateral treatment or have previous contralateral thalamotomy 1, 5
Beta-blockers should be avoided in patients with chronic obstructive pulmonary disease, bradycardia, or congestive heart failure, but may provide dual benefits for patients with both essential tremor and hypertension 3

The American Academy of Neurology recommends first-line treatment with propranolol (80-240 mg/day) or primidone to address both voice and postural tremor components simultaneously in essential tremor 6
MRI-guided focused ultrasound thalamotomy targeting the VIM nucleus can provide sustained improvement (56% tremor reduction at 2-4 years) for both manifestations, according to the American Association of Neurological Surgeons 6

The American Academy of Otolaryngology-Head and Neck Surgery notes that the diagnostic validity of laryngeal electromyography for vocal tremor remains unknown, and clinical examination and observation of tremor characteristics across multiple body regions remain the primary diagnostic approach 7, 8, 9

Voice tremor is a recognized manifestation of essential tremor and frequently accompanies postural tremor of the limbs, indicating involvement of the laryngeal musculature in this disorder. 10

Although spasmodic dysphonia, amyotrophic lateral sclerosis, multiple sclerosis, and Parkinson’s disease can also produce dysphonia, the concurrent presence of head tremor and action tremor of the arms strongly favors essential tremor as the underlying cause. 10