CEREBROVASCULAR ATHEROSCLEROSIS AND COGNITION IN PATIENTS WITH ALZHEIMER'S DISEASE

Abstract

Background: Vascular risk factors are known to be associated with increased prevalence of Alzheimer’s disease (AD) and poorer outcome of the disease. Most studies investigating, the relationship between the cerebrovascular diseases and AD focused on small vessel disease, however, the relationship between the large vessel disease and AD are relatively sparse. The objectives of this study were to compare the degree of atherosclerosis markers of large vessels between AD patients and healthy controls and to investigate the relationship between these markers and neuropsychological test performances in patients with AD. Methods: A total of sixtythree AD patients, aged 55 to 90 (mean age 73.6 years, 41 women and 22 men), underwent carotid duplex sonography and magnetic resonance angiography (MRA).All the participants completed detailed neuropsychological evaluation with Seoul neuropsychological screening battery (SNSB) which examined attention, language and related functions, visuospatial functions, verbal and visual memory, frontal and executive functions, Korean version of mini-mental status examination (K-MMSE) and clinical dementia rating scale.A total of eighty-six healthy controls (mean age 60.7 years, 19 women and 67 men) who completed carotid duplex sonography were recruited for comparison. The severity of cerebrovascular atherosclerosis markers were measured by carotid plaque-score, intima-media thickness (IMT), and intracranial atherosclerotic stenosis. Statistical analyses were performed using SPSS version 21.0. Results: The plaque-score of carotid artery (1.35 6 1.20 vs. 0.66 6 0.91) was significantly higher in patients with AD than healthy control (p1⁄40.023) after adjustment of age, sex, hypertension, diabetes mellitus, and IMT. In AD patients, the presence of carotid plaque was associated with a lower Seoul Verbal Learning Test (SVLT)immediate recall score (p1⁄40.026) and a lower Controlled Oral Word Association Test (COWAT) phonemic test score (p1⁄40.044). Moreover, carotid IMTwas associated with higher error rates (p1⁄40.027) and lower correction rates (p1⁄40.018) of the Stroop-word test in AD patients. A severity of intracranial arterial stenosis was associated with poorer performances on SVLT immediate recall p1⁄40.002), SVLT delayed recall (p1⁄40.013), Ray Complex Figure Test (RCFT) immediate recall (p1⁄40.000), RCFT delayed recall (p1⁄40.000) and Stroop-color test correction rate (p1⁄40.007).Conclusions: The presence of carotid plaque is more common in AD patients than healthy controls. Carotid atherosclerosis influenced frontal executive functions, and intracranial atherosclerotic stenosis was associated with memory functions in AD patients. These findings suggest that large artery disease may impact on cognitive decline in patients with AD. Future studies are needed to clarify the mechanisms of how large artery disease interacts with AD and affects cognitive decline.