Application of an amyloid and tau classification system in subcortical vascular cognitive impairment patients
To apply an AT (Aβ/tau) classification system to subcortical vascular cognitive impairment (SVCI) patients following recently developed biomarker-based criteria of Alzheimer’s disease (AD), and to investigate its clinical significance.
We recruited 60 SVCI patients who underwent the neuropsychological tests, brain MRI, and 18F-florbetaben and 18F-AV1451 PET at baseline. As a control group, we further recruited 27 patients with AD cognitive impairment (ADCI; eight Aβ PET-positive AD dementia and 19 amnestic mild cognitive impairment). ADCI and SVCI patients were classified as having normal or abnormal Aβ (A−/A+) and tau (T−/T+) based on PET results. Across the three SVCI groups (A−, A+T−, and A+T+SVCI), we compared longitudinal changes in cognition, hippocampal volume (HV), and cortical thickness using linear mixed models.
Among SVCI patients, 33 (55%), 20 (33.3%), and seven (11.7%) patients were A−, A+T−, and A+T+, respectively. The frequency of T+ was lower in A+SVCI (7/27, 25.9%) than in A+ADCI (14/20, 70.0%, p = 0.003) which suggested that cerebral small vessel disease affected cognitive impairments independently of A+. A+T−SVCI had steeper cognitive decline than A−SVCI. A+T+SVCI also showed steeper cognitive decline than A+T−SVCI. Also, A+T−SVCI had steeper decrease in HV than A−SVCI, while cortical thinning did not differ between the two groups. A+T+SVCI had greater global cortical thinning compared with A+T−SVCI, while declines in HV did not differ between the two groups.
This study showed that the AT system successfully characterized SVCI patients, suggesting that the AT system may be usefully applied in a research framework for clinically diagnosed SVCI.
KeywordsAmyloid-β Tau Classification Subcortical vascular cognitive impairment Longitudinal changes
Subcortical vascular cognitive impairment
National Institute on Aging and Alzheimer’s Association
Positron emission tomography
Cerebral small vessel disease
Mild cognitive impairment
Alzheimer’s disease–related cognitive impairment
White matter hyperintensities
Magnetic resonance imaging
Alzheimer’s disease dementia
Standardized uptake value ratios
Region of interest
Partial volume effect
Fluid-attenuated inversion recovery
Brain Aβ plaque load
Seoul Neuropsychological Screening Battery
Seoul Verbal Learning Test
Rey–Osterrieth Complex Figure Test
Korean version of the Boston Naming Test
Mini-Mental State Examination
Clinical Dementia Rating sum of boxes
Analysis of variance
Analysis of covariance
This research was supported by funds (2018-ER6202-01) from Research of Korea Centers for Disease Control and Prevention; the Brain Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (2016M3C7A1913844); NRF grant funded by the Korea government (2017R1A2B2005081)
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflicts of interest.
Role of the funder
The funders had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; or decision to submit the manuscript for publication.
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
Informed consent was obtained from all individual participants included in the study.
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