Structural correlates of apathy in Alzheimer's disease.

Apathy is the most common noncognitive symptom in Alzheimer's disease (AD). The structural correlates of apathy in AD have not yet been described. We analyzed magnetic resonance imaging data of 35 AD patients with and without apathy. There was a significant linear association between apathy severity and cortical gray matter atrophy in the bilateral anterior cingulate [Brodmann area (BA) 24; r = 0.39-0.42, p = 0.01] and left medial frontal cortex (BA 8 and 9; r = 0.4, p < 0.02). Left mean cingulate cortical thinning predicted the presence/absence of apathy at the trend level of significance. Our study demonstrates a strong association between apathy and the integrity of medial frontal regions in AD.