What are the hallmark motor symptoms of Parkinson disease?

• A. Tremor only
• B. Resting tremor, rigidity, bradykinesia, and postural instability
• C. Seizures
• D. Muscle atrophy only

Answer: (B)

Parkinson disease produces a characteristic pattern of motor dysfunction rooted in loss of dopamine in the basal ganglia. The hallmark features are a resting tremor (often pill-rolling) that appears when the body is at rest and lessens with movement, rigidity with increased muscle tone that can feel like a cogwheel bite or lead-pipe resistance, bradykinesia or slowness of initiating and performing movements, and postural instability that tends to develop later and increases the risk of falls. Together these signs define the typical motor presentation. Seizures or isolated muscle atrophy don’t fit the core motor pattern seen in Parkinson disease, which is why they aren’t considered hallmark features.