Background: Previous studies using magnetic resonance imaging (MRI) showed that dementia with Lewy bodies (DLB) had less atrophy in some medial temporal structures than Alzheimer’s disease (AD). However, very few studies have focused on the entorhinal cortex, which is closely related to episodic memory. We compared the degree of entorhinal cortex atrophy between the two types of dementia using the voxel-based specific regional analysis system for AD (VSRAD) targeting this region. Methods: The subjects consisted of 60 patients with DLB and 210 patients with AD. The degree of entorhinal cortex atrophy was quantified by application of the VSRAD to MRI data, and a Z score >2 was defined as significant atrophy. Results: The DLB group had significantly lower Z scores than the AD group (mean ± SD: 2.25 ± 1.10 vs. 2.85 ± 1.33, p < 0.01). The analysis of covariance with possible confounding factors as covariates also showed that Z scores were significantly lower in the DLB group than in the AD group (p < 0.01). The proportion of patients with atrophy was significantly lower in the DLB group than in the AD group (53 vs. 72%, p < 0.01). Conclusions: The present study using the VSRAD suggests that DLB shows less atrophy in the entorhinal cortex than AD.
Background:
Early-onset Semantic dementia (EOSD) and early-onset Alzheimer's disease (EOAD) are often difficult to clinically differentiate in the early stages of the diseases because of the overlaps of clinical symptoms such as language symptoms. We compared the degree of atrophy in medial temporal structures between the two types of dementia using the voxel-based specific regional analysis system for Alzheimer’s disease (VSRAD).
Methods:
The participants included 29 (age: 61.7±4.5 years) and 39 (age: 60.2±4.9 years) patients with EOSD and EOAD, respectively. The degree of atrophy in medial temporal structures was quantified using the VSRAD for magnetic resonance imaging data. Receiver operating characteristic (ROC) analysis was performed to distinguish patients with EOSD and EOAD using the mean Z score (Z-score) in bilateral medial temporal structures and the absolute value (laterality score) of the laterality of Z-score (| right–left |) for indicating the degree of asymmetrical atrophy in medial temporal structures.
Results:
The EOSD group had significantly higher Z and laterality scores than the EOAD group (Z-scores: mean ± standard deviation: 3.74±1.05 vs. 1.56±0.81, respectively; P<0.001; laterality score: mean ± standard deviation: 2.35±1.23 vs. 0.68±0.51, respectively; P<0.001). In ROC analysis, the sensitivity and specificity to differentiate EOSD from EOAD by a Z-score of 2.29 were 97% and 85%, respectively and by the laterality score of 1.05 were 93% and 85%, respectively.
Conclusions:
EOSD leads to more severe and asymmetrical atrophy in medial temporal structures than EOAD. The VSRAD may be useful to distinguish between these dementias that have several clinically similar symptoms.
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