Which disease is characterized by rigidity, stiffness, resting tremor, and masked facies?

Parkinson's disease is characterized by a classic triad of symptoms: rigidity, bradykinesia (which can be interpreted as stiffness), and resting tremor. Additionally, patients may exhibit masked facies, which refers to a reduction in facial expressiveness, giving the appearance of a mask-like face. These features result from the degeneration of dopaminergic neurons in the substantia nigra, leading to the characteristic motor symptoms associated with the disease.

In Parkinson's disease, the rigidity can manifest as increased muscle tone throughout the body, making it difficult for the patient to move freely. The resting tremor typically occurs when the patient is at rest and is often described as a "pill-rolling" motion. Masked facies contributes to the overall appearance of persons with Parkinson's, as they may show reduced facial movements.

The other diseases listed have different hallmark features and do not encompass the full spectrum of symptoms unique to Parkinson's disease. For example, Huntington's disease is characterized by chorea and cognitive decline, Wilson's disease involves hepatic symptoms and movement disorders related to copper accumulation, and Alzheimer's disease predominantly affects cognitive function with less emphasis on motor rigidity or tremors. Thus, the distinctive combination of rigidity, resting tremor, and masked fac