Which of the following diseases can lead to significant cognitive decline?

Cognitive decline can be primarily attributed to conditions that directly affect the brain's structure or function. Huntington's disease is a genetic disorder that causes the progressive breakdown of nerve cells in the brain. This neurodegeneration leads to a variety of symptoms, including cognitive decline, decision-making difficulties, and changes in mood and behavior.

As the disease progresses, individuals may experience significant impairments in their cognitive abilities, ultimately requiring comprehensive care as the brain's functions deteriorate. The direct impact on brain cells and the nature of the disease makes it a well-known cause of cognitive decline.

In contrast, while diabetes and hypertension can have secondary effects on cognitive function, their primary effects are not as directly linked to cognitive decline as Huntington's disease. Asthma, primarily a respiratory condition, does not typically lead to cognitive decline in itself, making it less relevant in this context.