Which of the following is an etiology for cortical dementia?

Cortical dementia refers to a group of disorders that primarily affect the cerebral cortex, leading to impairments in memory, thinking, and other cognitive functions. Alzheimer's disease is classified as a cortical dementia because it specifically impacts the areas of the brain responsible for higher cognitive functions, including memory and reasoning. The pathology of Alzheimer's is characterized by the presence of amyloid plaques and neurofibrillary tangles, which contribute to neuron degeneration in the cortex, resulting in the hallmark symptoms of the disease.

The other options listed, while they can involve cognitive decline and dementia-like symptoms, do not primarily stem from cortical degeneration. For instance, amyotrophic lateral sclerosis primarily affects motor neurons and causes weakness and atrophy rather than significant cortical cognitive impairment. Parkinson's disease involves both motor and cognitive symptoms, but its main effects are on the basal ganglia rather than the cortex. Huntington's disease can lead to cognitive deterioration but also involves subcortical structures. In contrast, Alzheimer's disease's direct impact on the cortical areas makes it the correct choice for etiology specifically associated with cortical dementia.