What characterizes Parkinson's disease?

Parkinson's disease is primarily characterized as a disorder of the central nervous system that significantly impacts movement. This condition often leads to a range of motor symptoms, including tremors, stiffness, slowness of movement, and impaired balance and coordination. The tremors typically start in one hand or limb and may become more prominent during rest or stress.

As the disease progresses, it can affect other aspects of daily functioning, including walking and completing routine tasks. The underlying problem in Parkinson's disease is primarily due to the degeneration of dopamine-producing neurons in a specific area of the brain known as the substantia nigra. This loss of dopamine results in the motor symptoms commonly associated with the disease.

In contrast, the other options present either unrelated or distinct medical conditions that do not accurately define Parkinson's disease. For instance, sudden onset of severe headaches would likely be associated with migraines or other types of headaches rather than a neurodegenerative disorder. A gradual degeneration of muscle tissue can happen in various conditions but does not specifically capture the unique aspects of Parkinson’s. Similarly, uncontrolled thoughts may describe mental health disorders but do not reflect the motor abnormalities that characterize Parkinson’s disease. Thus, option C precisely encapsulates the core features of Parkinson's disease.