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Effects of education on the progression of early- versus late-stage mild cognitive impairment

Published online by Cambridge University Press:  04 December 2012

Byoung Seok Ye
Affiliation:
Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
Sang Won Seo*
Affiliation:
Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
Hanna Cho
Affiliation:
Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
Seong Yoon Kim
Affiliation:
Department of Psychiatry, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea
Jung-Sun Lee
Affiliation:
Department of Psychiatry, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea
Eun-Joo Kim
Affiliation:
Department of Neurology, Pusan National University School of Medicine, Pusan, Republic of Korea
Yunhwan Lee
Affiliation:
Departments of Preventive Medicine and Public Health, Ajou University School of Medicine, Suwon, Republic of Korea
Joung Hwan Back
Affiliation:
Departments of Preventive Medicine and Public Health, Ajou University School of Medicine, Suwon, Republic of Korea
Chang Hyung Hong
Affiliation:
Department of Psychiatry, Ajou University School of Medicine, Suwon, Republic of Korea
Seong Hye Choi
Affiliation:
Department of Neurology, Inha University School of Medicine, Incheon, Republic of Korea
Kyung Won Park
Affiliation:
Department of Neurology, Dong-A University College of Medicine, Pusan, Republic of Korea
Bon D. Ku
Affiliation:
Department of Neurology, Kwandong University College of Medicine, Gyeonggi-do, Republic of Korea
So Young Moon
Affiliation:
Department of Neurology, Ajou University School of Medicine, Suwon, Republic of Korea
SangYun Kim
Affiliation:
Department of Neurology, Seoul National University Bundang Hospital, Seongnam, Republic of Korea
Seol-Heui Han
Affiliation:
Department of Neurology, Konkuk University College of Medicine, Seoul, Republic of Korea
Jae-Hong Lee
Affiliation:
Department of Neurology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea
Hae-Kwan Cheong
Affiliation:
Department of Social and Preventive Medicine, School of Medicine, Sungkyunkwan University, Suwon, Republic of Korea
Duk L. Na
Affiliation:
Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
*
Correspondence should be addressed to: Sang Won Seo, MD, PhD, Department of Neurology, Samsung Medical Center, Sunkyunkwan University School of Medicine, 50 Ilwon-dong, Kangnam-ku, Seoul 135-710, Republic of Korea. Phone: +82-2-3410-1233; Fax: +82-2-3410-0052. Email: sangwonseo@empal.com.

Abstract

Background: Highly educated participants with normal cognition show lower incidence of Alzheimer's disease (AD) than poorly educated participants, whereas longitudinal studies involving AD have reported that higher education is associated with more rapid cognitive decline. We aimed to evaluate whether highly educated amnestic mild cognitive impairment (aMCI) participants show more rapid cognitive decline than those with lower levels of education.

Methods: A total of 249 aMCI patients enrolled from 31 memory clinics using the standard assessment and diagnostic processes were followed with neuropsychological evaluation (duration 17.2 ± 8.8 months). According to baseline performances on memory tests, participants were divided into early-stage aMCI (−1.5 to −1.0 standard deviation (SD)) and late-stage aMCI (below −1.5 SD) groups. Risk of AD conversion and changes in neuropsychological performances according to the level of education were evaluated.

Results: Sixty-two patients converted to AD over a mean follow-up of 1.43 years. The risk of AD conversion was higher in late-stage aMCI than early-stage aMCI. Cox proportional hazard models showed that aMCI participants, and late-stage aMCI participants in particular, with higher levels of education had a higher risk of AD conversion than those with lower levels of education. Late-stage aMCI participants with higher education showed faster cognitive decline in language, memory, and Clinical Dementia Rating Sum of Boxes (CDR-SOB) scores. On the contrary, early-stage aMCI participants with higher education showed slower cognitive decline in MMSE and CDR-SOB scores.

Conclusions: Our findings suggest that the protective effects of education against cognitive decline remain in early-stage aMCI and disappear in late-stage aMCI.

Type
Research Article
Copyright
Copyright © International Psychogeriatric Association 2012

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