What is appendicular postural tension and rest tremor?

From the Guidelines

Appendicular postural tension and rest tremor are key neurological symptoms often associated with Parkinson's disease, characterized by increased muscle tone and involuntary rhythmic shaking, respectively. These symptoms are commonly seen in Parkinsonian syndromes, a group of movement disorders that include Parkinson's disease (PD), progressive supranuclear palsy (PSP), multiple system atrophy (MSA), and corticobasal degeneration (CBD) 1. The clinical presentation of PD, the most common Parkinsonian syndrome, is characterized by resting tremor, bradykinesia, and rigidity, which are related to progressive degeneration of the dopaminergic neurons in the substantia nigra projecting to the striatum 1. Appendicular postural tension refers to the increased muscle tone or rigidity that affects the limbs of the body, causing stiffness and resistance to passive movement, while rest tremor is an involuntary rhythmic shaking that occurs when the affected body part is relaxed and supported against gravity. Key features of these symptoms include:

• Increased muscle tone or rigidity in the limbs
• Involuntary rhythmic shaking, typically between 4-6 Hz
• Symptoms that are constant or have a ratchet-like quality when combined with tremor
• Disappearance of tremor during voluntary movement These symptoms result from dysfunction in the basal ganglia, particularly the loss of dopaminergic neurons in the substantia nigra, and are essential for the diagnosis and management of underlying neurological conditions 1. Treatment typically involves dopamine replacement therapy with medications, as well as physical therapy and regular exercise to maintain mobility and function. Early recognition of these symptoms is crucial for timely diagnosis and management of Parkinsonian syndromes, and imaging remains an essential diagnostic tool in the evaluation of patients presenting with these symptoms 1.

From the Research

Definition and Classification of Tremors

• Tremor is an involuntary, rhythmic, oscillatory movement of a body part, which can be classified based on its activation condition, topographic distribution, and frequency 2, 3, 4, 5.
• Tremors can be categorized into different types, including:
  • Resting tremors: occur in a body part that is relaxed and completely supported against gravity 3, 4, 5.
  • Action tremors: occur with voluntary contraction of a muscle and can be further subdivided into postural, isometric, and kinetic tremors 3, 4, 5.
• Appendicular postural tension and rest tremor can be understood as a type of tremor that occurs in the appendages (limbs) and is characterized by postural tension and resting tremor.

Types of Tremors

• Essential tremor: a common pathologic tremor that affects 0.4% to 6% of the population, typically transmitted in an autosomal-dominant fashion, and is characterized by postural and kinetic tremors 2, 3, 4.
• Parkinsonian tremor: a type of resting tremor that occurs in patients with Parkinson's disease, typically asymmetric, and becomes less prominent with voluntary movement 2, 3, 4.
• Other types of tremors include cerebellar, dystonic, drug- or metabolic-induced, and orthostatic tremors 3, 4, 5.

Diagnosis and Evaluation

• The diagnosis of tremor is based on clinical information obtained from a thorough history and physical examination 3, 4, 6, 5.
• The evaluation of a patient with tremor should begin with a tremor history and a focused neurologic examination, attending to the nuances of tremor phenomenology 5.
• Single-photon emission computed tomography and transcranial ultrasonography may be useful in diagnosing Parkinson's disease and other tremor disorders 3, 4.