From the Guidelines
Tremors can be classified into several types, including resting tremor, action tremor, physiologic tremor, and psychogenic tremor, with the most recent evidence suggesting that accurate diagnosis and differentiation are crucial for effective management and treatment 1.
Types of Tremors
- Resting tremor: occurs when muscles are relaxed, typically disappearing with voluntary movement, and is classically seen in Parkinson's disease with its characteristic "pill-rolling" motion between thumb and forefinger.
- Action tremor: includes postural, kinetic, and intention tremors, and occurs during voluntary muscle contraction.
- Physiologic tremor: a normal phenomenon that can be exaggerated by factors like caffeine, anxiety, or certain medications.
- Psychogenic tremor: a rare type of tremor that is caused by psychological or emotional factors.
Differentiation of Tremors
To differentiate these tremors clinically, it is essential to observe:
- When the tremor occurs (at rest or with action)
- Its frequency (slow or fast)
- Amplitude
- Body parts affected
- Associated symptoms
- Aggravating factors
- The pattern of tremor progression
- Family history
- Response to alcohol
- Presence of other neurological signs The most recent study 1 emphasizes the importance of periodic neurologic enquiry/assessments and standardized rating scales to ensure prompt diagnosis and treatment of tremors and other movement disorders.
Clinical Approach
In clinical practice, it is crucial to consider the underlying cause of the tremor and to differentiate between various types of tremors to provide effective treatment and management. According to the most recent evidence 1, collaboration with a specialist, such as a movement disorders neurologist, is recommended for patients with suggestive features of Parkinson's disease or other movement disorders.
From the Research
Types of Tremors
- Enhanced physiologic tremor: can be enhanced by anxiety, medication use, caffeine intake, or fatigue 2
- Essential tremor: the most common pathologic tremor, affects 0.4% to 6% of the population, and is characterized by symmetric bilateral postural and kinetic tremor 2, 3
- Parkinsonian tremor: typically unilateral, occurs at rest, and becomes less prominent with voluntary movement 2, 3
- Cerebellar tremor: occurs due to damage to the cerebellum or its connections 2
- Dystonic tremor: a type of tremor that occurs in patients with dystonia, a movement disorder characterized by involuntary muscle contractions 2, 4
- Drug- or metabolic-induced tremor: can be caused by certain medications or metabolic disorders 2
- Psychogenic tremor: characterized by abrupt onset, spontaneous remission, changing tremor characteristics, and extinction with distraction 2
Differentiation of Tremors
- Resting tremors: occur in a body part that is relaxed and completely supported against gravity, typically seen in Parkinson's disease 2
- Action tremors: occur with voluntary contraction of a muscle and can be further subdivided into postural, isometric, and kinetic tremors 2
- Activation condition: categorize the tremor based on its activation condition, such as rest, postural, or kinetic 2
- Topographic distribution: consider the distribution of the tremor, such as unilateral or bilateral 2, 3
- Frequency: consider the frequency of the tremor, such as high-frequency or low-frequency 2
Diagnostic Evaluation
- Clinical information: obtain a thorough history and physical examination to diagnose tremor 2
- Single-photon emission computed tomography: can be used to visualize the integrity of the dopaminergic pathways in the brain 2
- Transcranial ultrasonography: may be useful to diagnose Parkinson's disease 2
- Diagnostic criteria: use standardized criteria to diagnose and differentiate between various types of tremors 5, 4