Final answer:
The terminal phase of Alzheimer’s disease is marked by severe brain atrophy, pronounced amyloid plaques and neurofibrillary tangles, substantial memory loss, and cognitive decline. This phase is the most severe and symptoms are significantly disruptive. Diagnosis of AD during life is based on symptom progression and severity.
Step-by-step explanation:
Terminal Phase Findings of Alzheimer’s Disease
Alzheimer’s disease (AD) progresses through different stages and is characterized by a variety of symptoms and brain changes. In the terminal phase of Alzheimer’s, which is considered the most severe stage of the disease, the brain undergoes significant atrophy. This involves a dramatic neurodegeneration with notable shrinkage particularly within the ventricles and hippocampus, as illustrated in Figure 35.30. The presence of amyloid plaques and neurofibrillary tangles, primarily composed of misshapen tau protein, are hallmark pathological features of AD and are most pronounced in this terminal stage.
Microscopically, these abnormal changes include disintegration of microtubules, development of amyloid plaques between brain cells, accumulation of neurofibrillary tangles inside of neurons, and loss of synapses. The neuronal dysfunction and loss in the hippocampus area are severe, leading to profound memory loss and cognitive decline. The terminal phase is associated with the most disruptive symptoms, including significant memory loss, confusion, difficulty with planning and executing tasks, and considerable personality changes. Sensory abnormalities, like the reduced ability to smell certain scents, can also surface.
Although AD can currently only be definitively diagnosed after death, through examination of brain tissues for plaques and tangles, the progression of symptoms gives clinicians the ability to ascertain the likely presence and stage of the disease in living patients.