Which disease is characterized by progressive neurodegeneration with degradation of dopamine affecting motor function?

• A. Parkinson's Disease
• B. Multiple Sclerosis
• C. Alzheimer's Disease
• D. Amyotrophic Lateral Sclerosis

Answer: (A)

Loss of dopamine-producing neurons in the basal ganglia leads to impaired motor control, which is the hallmark of Parkinson's disease. When dopaminergic neurons in the substantia nigra degenerate, dopamine levels in the striatum drop, disrupting the normal balance of the motor circuits that initiate and regulate movement. This produces the classic motor features: slow movement (bradykinesia), muscle rigidity, a resting tremor, and balance difficulties, all of which progress over time as degeneration continues. Other neurological diseases may affect movement, but they don’t center on dopaminergic loss in the basal ganglia: multiple sclerosis involves autoimmune demyelination with varied symptoms, Alzheimer's is mainly cognitive decline, and amyotrophic lateral sclerosis targets motor neurons leading to weakness and wasting rather than dopamine-related motor dysfunction.