From the Guidelines
Tremors are classified into three main types: resting, postural, and kinetic, each with distinct characteristics and associated neurological conditions, as outlined in the movement disorders and neurodegenerative diseases criteria 1. The main difference between these tremor types lies in when they occur and the underlying conditions they are associated with.
- Resting tremors occur when the affected body part is completely supported against gravity and not actively moving, typically disappearing with voluntary movement, and are characteristic of Parkinson's disease, as described in the context of Parkinsonian syndromes 1.
- Postural tremors appear when maintaining a position against gravity, such as holding arms outstretched, and are commonly seen in essential tremor.
- Kinetic tremors occur during voluntary movement of a body part, becoming most noticeable during goal-directed movements, and are often associated with cerebellar disorders, multiple sclerosis, or certain medications. The distinction between these tremor types is crucial for accurate diagnosis and appropriate treatment selection, as each type may respond differently to medications, highlighting the importance of correct diagnosis in managing Parkinsonian syndromes and other movement disorders 1.
From the Research
Types of Tremors
- Resting tremor: occurs in a body part that is relaxed and completely supported against gravity 2
- Action tremor: occurs with voluntary contraction of a muscle and can be further subdivided into: + Postural tremor: occurs when a body part is held in a fixed position 2, 3 + Kinetic tremor: occurs during voluntary movement 2, 3 + Intention tremor: a type of kinetic tremor that occurs during purposeful movement 4
Characteristics of Tremors
- Resting tremor is typically asymmetric and becomes less prominent with voluntary movement, often seen in Parkinson's disease 2
- Action tremor can be symmetric or asymmetric, and may be seen in essential tremor, enhanced physiologic tremor, and other conditions 3, 4
- Kinetic tremor is often more severe than postural tremor in essential tremor, with approximately 95% of cases showing more severe kinetic tremor 5
Diagnosis and Classification
- The diagnosis of tremor is based on clinical information obtained from a thorough history and physical examination 2
- Tremors can be classified based on their activation condition, topographic distribution, and frequency 2
- The primary type of tremor in essential tremor is kinetic rather than postural, with recognition of this feature having potential diagnostic value for clinicians 5