Correlation between gray matter volume in the temporal lobe and depressive symptoms in patients with Alzheimer's disease.
Recent studies have suggested that depression might be an aggravating factor in Alzheimer's disease (AD). The aim of the study was to compare depressive symptoms and gray matter volume between AD patients with comorbid depression and patients with dementia only. Forty-nine patients with AD, 57 with mild cognitive impairment (MCI), and 50 healthy control subjects were assessed using the Consortium to Establish a Registry for Alzheimer's disease (CERAD) and the Geriatric Depression Scale (GDS). All magnetic resonance imaging (MRI)s were analyzed using voxel-based morphometry (VBM). Seventeen AD patients with depression versus 32 patients with dementia only showed decreased immediate recall for a word list (8.7±1.1 vs. 10.1±1.5, z=3.6, p<0.01) and constructional praxis scores (3.7±0.9 vs. 5.3±2.1, z=2.5, p=0.01). Compared to 32 patients with dementia, seventeen AD patients with depression showed decreased gray matter volume in the left inferior temporal gyrus (-56, -19, -31; KE=578, t=3.80, Puncorr<0.001). The MCI group showed decreased gray matter volume in the right hippocampal gyrus compared to healthy control group. Our results suggest that depressive symptoms may be associated with the volume changes of frontal and temporal lobe in patients with AD.