What is the primary feature of a resting tremor in Parkinson's disease?

The primary feature of a resting tremor in Parkinson's disease is that it is present when the individual is completely at rest. This characteristic is distinct from tremors associated with other conditions or types of movement disorders, which may occur during purposeful movement or activity. In Parkinson's disease, the resting tremor typically manifests in the hands, often described as a "pill-rolling" motion, and tends to diminish or disappear when the patient begins to move or engages in voluntary activity.

This hallmark feature is crucial for diagnosing Parkinson's disease and differentiating it from other forms of tremors, which may present differently or in various contexts such as during sleep or with muscle involvement beyond typical resting positions. The understanding of this specific occurrence helps healthcare professionals in both assessment and treatment strategies for individuals diagnosed with the condition.