From the Guidelines
Tremors can be distinguished into various types, including essential tremor, parkinsonian tremor, and other types, each with distinct characteristics that aid in diagnosis and management. The characteristics of these tremor types are as follows:
- Essential tremor is primarily a postural and kinetic tremor affecting the hands at 4-12 Hz, often worsened by stress and improved with alcohol, and can be treated with beta-blockers such as propranolol 1.
- Parkinsonian tremor is a rest tremor that occurs when the affected body part is relaxed and supported against gravity, typically disappearing with voluntary movement, and is most commonly seen in Parkinson's disease, presenting as a 4-6 Hz "pill-rolling" motion of the fingers 1.
- Other types of tremors include:
- Physiologic tremor: a normal phenomenon present in everyone at 8-12 Hz, becoming enhanced during anxiety, caffeine use, or with certain medications.
- Cerebellar tremors: slow (2-4 Hz) intention tremors that worsen as the limb approaches a target, often accompanied by dysmetria and dysdiadochokinesia.
- Dystonic tremors: occur in body parts affected by dystonia.
- Psychogenic tremors: have variable frequency, distractibility, and sudden onset.
- Drug-induced tremors: can present in various patterns depending on the medication, commonly seen with lithium, valproate, antipsychotics, and stimulants. Understanding these distinctive features is crucial for accurate diagnosis and appropriate management of different tremor types, as highlighted in the evaluation of Parkinsonian syndromes, which can be challenging to diagnose based on clinical features alone, and imaging remains an essential diagnostic tool 1.
From the Research
Characteristics of Tremor Types
- Essential tremor (ET) is a bilateral postural tremor, with a prevalence of 0.4% in the overall population and 4-7% in persons over age 65 2
- ET presents in most cases as a more or less symmetrical postural and kinetic tremor, and may manifest not only in the hands but also in the head and voice 3
- Parkinsonian tremor is normally a tremor at rest, starts asymmetrically, and frequently involves the legs and face 3, 4
- Cerebellar tremor is intentional, and orthostatic tremor has a high frequency, mainly manifests in the legs, and gives rise to postural instability 3, 4
- Dystonic tremor is an action tremor of the affected region of the body 3, 4
Clinical Features and Diagnosis
- Tremor can be categorized based on its activation condition, topographic distribution, and frequency 5
- Diagnosis of tremor is based on clinical information obtained from a thorough history and physical examination 5
- Electromyography is a simple and quick method to calculate tremor frequency and amplitude for assisting diagnosis 4
- Single-photon emission computed tomography may be useful to diagnose Parkinson disease in particularly difficult cases 5
Treatment Options
- Treatment for majority of tremor syndrome is purely symptomatic, and is similar regardless of the underlying cause of the tremor 4
- Postural and action tremors respond to non-selective beta-blockers, primidone, some antiepileptics, and benzodiazepines 3, 6
- Classical rest tremors are improved by dopaminergic substances or anticholinergics 3, 6
- Dystonic tremor may be successfully treated by injections of botulinum toxin 3, 4
- Orthostatic tremor responds to gabapentin or benzodiazepines in some patients 3, 4
- Stereotactic thalamotomy or thalamic stimulation may be considered in severely handicapped patients with refractory tremors 3, 6