Neuropsychological Evaluation and Cerebral Blood Flow Effects of Apolipoprotein E4 in Alzheimer's Disease Patients after One Year of Treatment: An Exploratory Study

Background: Alzheimer's disease (AD) is affected by apolipoprotein E (ApoE); however, its effects assessed by means of cognitive tests and by neuroimaging have not been sufficiently studied. Methods: We administered the Alzheimer's Disease Assessment Scale (ADAS) and single-photon emission computed tomography imaging in patients with AD medicated with donepezil at baseline and after 1 year. Patients were classified as with or without ApoE4 and we evaluated the progress of AD. Results: Analysis of covariance showed that cerebral blood flow after 1 year in subjects with ApoE4 is significantly reduced in some areas including the left lenticular nucleus, left thalamus, and right hippocampus compared with subjects without ApoE4. Paired t tests showed significantly reduced blood flow in several regions including the right hippocampus in subjects with ApoE4 and significant deterioration of ideational praxis in subjects without ApoE4. Conclusion: This study provides evidence that supports the notion of ApoE4 playing an important role in the progress of AD.