Which disorder is characterized by involuntary movements and cognitive decline?

Huntington's Disease is characterized by a combination of involuntary movements, known as chorea, and cognitive decline. This neurodegenerative disorder is caused by a genetic mutation that leads to progressive degeneration of brain cells, impacting both motor function and cognitive abilities.

Individuals with Huntington's may experience uncontrollable jerking or writhing movements, along with significant changes in personality, mood swings, and impaired judgment. The progression of the disease leads to increasing levels of cognitive impairment, which can affect daily functioning and quality of life.

In contrast, while Parkinson's Disease includes some involuntary movements, such as tremors and rigidity, it is primarily characterized by motor symptoms without the cognitive decline as a defining early feature. Multiple Sclerosis mainly affects the central nervous system and can lead to a variety of symptoms, but it does not specifically feature the same movement disorders or the distinct cognitive decline associated with Huntington's. Alzheimer's Disease is focused primarily on cognitive decline and memory loss, with fewer involuntary movements compared to Huntington's.

Thus, Huntington's Disease uniquely fits the description of a disorder that includes both involuntary movements and cognitive decline, making it the correct answer.