Different Atrophic Patterns in Early- and Late-onset Alzheimer's Disease and Evaluation of Clinical Utility of a Method of Regional Z-score Analysis Using Voxel-based Morphometry

Background/aims: We evaluated the differential patterns of brain atrophy in early- and late-onset Alzheimer's disease (AD) by measuring regional z-scores of voxel-based morphometry and assessed the availability of the method for clinical use.

Methods: The first 50 patients with probable AD were compared to 83 age-matched control subjects to identify the brain atrophy. Regions of interest were set in the areas showing z-scores >4. To find substantial differences in the atrophy pattern, principal component analysis was performed. The second group of 56 patients with memory complaints entered the study for evaluation of the clinical use of the model.

Results: The centers of the regions of interest were the amygdala, anterior hippocampi, posterior hippocampi, temporal cortices and subcallosal cortex, and left posterior cingulate cortex (PCC). Eigenvectors of the temporal cortices and left PCC showed counter-directions to those of patient age, suggesting that patients with younger onset age were preferentially associated with atrophy of those regions. Differential analyses of the second group showed high availability for the detection of abnormal brain atrophy in people with subjective memory complaints.

Conclusion: AD with earlier onset is preferentially related to PCC and temporal lobe atrophy. Voxel-based morphometry can be statistically analyzed, and this method has the potential for bias-free assessment of brain atrophy.