Which of the following are common signs of Parkinson's disease?

• A. Seizures
• B. Visual disturbances
• C. Tremors, bradykinesia, akinesia, and postural instability
• D. Hearing loss

Answer: (C)

Parkinson's disease is a movement disorder caused by loss of dopamine-producing neurons in the substantia nigra. The most characteristic signs are motor in nature: resting tremor, bradykinesia (slowness of movement), akinesia (difficulty initiating movement), and postural instability (impaired balance). These together reflect the disruption of dopamine pathways that regulate movement. Seizures, visual disturbances, and hearing loss are not defining features of Parkinson's, though non-motor symptoms can occur in PD; the combination of tremor with slowed or difficult movement and balance problems best captures the common signs.