Final answer:
Late stage Alzheimer's disease is characterized by significant brain atrophy, complete dependency on care, and loss of basic functions. The presence of amyloid plaques and neurofibrillary tangles are key molecular features leading to neuron loss and cognitive decline.
Step-by-step explanation:
Late Stage Alzheimer's Disease Characteristics
Alzheimer's disease (AD) is a progressive neurodegenerative disorder that over time leads to severe brain damage and cognitive decline. The late stage of AD is characterized by significant atrophy of the brain, resulting in patients becoming fully dependent on others for care. They often lose the ability to recognize family members, communicate effectively, and control basic functions such as bladder, bowel movements, and swallowing.
At the molecular level, there is a marked increase in amyloid plaques and neurofibrillary tangles, which contribute to neuron loss, especially in the hippocampus—an area critical for memory. These pathological changes lead to a decline in synaptic connections and ultimately the death of neurons.
The inability to definitively diagnose AD until after death complicates the fight against this disease. However, ongoing research seeks to understand the etiology of AD and develop potential treatment options. As of now, care for AD patients in the severe stage is focused on comfort and symptom management, as depicted in the scenario of Rosa's diagnosis and her doctor's conclusions based on her symptoms and test results.