Neuropathologic correlates of apathy in Alzheimer's disease.

Apathy is the most commonly observed behavioral disturbance in Alzheimer's disease (AD) and has been suggested to be frontally mediated. Neuritic plaque (NP) and neurofibrillary tangle (NFT) counts were performed for 8 brain regions in 29 subjects with definite AD. Neuropsychiatric Inventory (NPI) for autopsied subjects was obtained from questioning of caregivers of subjects included in the study. Chronic apathy and total NPI composite scores correlated with anterior cingulate NFT counts (r = 0.518, p = 0.01, and r = 0.438, p = 0.032). This analysis suggests that chronic apathy in AD correlates with a greater anterior cingulate NFT burden and that chronic behavioral changes are more reflective than acute changes of disease pathology.