title: Cognitive profiles and neuropsychiatric symptoms in Korean early-onset Alzheimer's disease patients: a CREDOS study.
abstract: OBJECTIVE
  Early-onset Alzheimer's disease (EOAD, onset age < 65 years) may differ from late-onset Alzheimer's disease (LOAD) in terms of cognitive profiles and neuropsychiatric symptoms. There have been few studies for Korean EOAD patients using well-structured databases. Previous studies focusing on cognitive profiles between the two groups had a variety of demographic data and comparability. The purpose of this study was to identify the unique profiles of cognitive functions and neuropsychiatric symptoms in Korean EOAD patients that differentiate from LOAD.
  
  
  METHODS
  Through propensity score matching, a total of 435 patients with EOAD and a total of 435 patients with LOAD were included in this nationwide, multicenter, hospital-based study. Each patient underwent comprehensive neurological examination, interview for caregiver, neuropsychological tests, and brain magnetic resonance imaging.
  
  
  RESULTS
  Neuropsychological test results showed worse performances on frontal/executive functions, visuospatial function, and visual memory in EOAD patients as compared to LOAD patients. In terms of neuropsychiatric symptoms, apathy was more common in EOAD patients, while delusions were more prevalent in LOAD patients. The differences in neuropsychiatric symptoms between the two groups were most pronounced in patients with the APOE ε4 allele, suggesting that neuropsychiatric symptoms in AD may be influenced by the APOE genotype.
  
  
  CONCLUSIONS
  Our results suggested that EOAD may be an important phenotype, fronto-parietal dysfunction, in the spectrum of AD, and this finding can provide for early diagnosis of EOAD patients.
authors.affiliation: Department of Neurology, Inje University Ilsan Paik Hospital, Goyang, Korea.
authors.forename: Hee Kyung
authors.initials: HK
authors.lastname: Park
authors.affiliation: Department of Neurology, Inha University School of Medicine, Incheon, Korea.
authors.forename: Seong Hye
authors.initials: SH
authors.lastname: Choi
authors.affiliation: Department of Neurology, Soonchunhyang University College of Medicine, Bucheon, Korea.
authors.forename: Sun A
authors.initials: SA
authors.lastname: Park
authors.affiliation: Department of Clinical Epidemiology and Biostatistics, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Hwa Jung
authors.initials: HJ
authors.lastname: Kim
authors.affiliation: Department of Preventive Medicine and Public Health, Ajou University School of Medicine, Suwon, Korea.
authors.forename: Yunhwan
authors.initials: Y
authors.lastname: Lee
authors.affiliation: Department of Neurology, Konkuk University Hospital, Konkuk University School of Medicine, Seoul, Korea.
authors.forename: Seol-Heui
authors.initials: SH
authors.lastname: Han
authors.affiliation: Department of Neurology, Pusan National University Hospital, Pusan National University School of Medicine and Medical Research Institute, Busan, Korea.
authors.forename: Eun-Joo
authors.initials: EJ
authors.lastname: Kim
authors.affiliation: Department of Neurology, Chonnam National University Medical School, Gwangju, Korea.
authors.forename: Byeong C
authors.initials: BC
authors.lastname: Kim
authors.affiliation: Department of Neurology, Myoungji Hosipital, Goyang, Korea.
authors.forename: Hyun Jeoung
authors.initials: HJ
authors.lastname: Han
authors.affiliation: Department of Neurology, Ajou University School of Medicine, Suwon, Korea.
authors.forename: So Young
authors.initials: SY
authors.lastname: Moon
authors.affiliation: Department of Neurology, Seoul St.Mary's Hospital, The Catholic University of Korea College of Medicine, Seoul, Korea.
authors.forename: Dong Won
authors.initials: DW
authors.lastname: Yang
authors.affiliation: Department of Neurology, Dong-A University College of Medicine, Busan, Korea.
authors.forename: Kyung Won
authors.initials: KW
authors.lastname: Park
authors.affiliation: Deaprtment of Neurology, Gil Medical Center, Gachon University of Medicine and Science, Incheon, Korea.
authors.forename: Kee Hyung
authors.initials: KH
authors.lastname: Park
authors.affiliation: Department of Neurology, Konyang University College of Medicine, Daejeon, Korea.
authors.forename: Bora
authors.initials: B
authors.lastname: Yoon
authors.affiliation: Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Sang Won
authors.initials: SW
authors.lastname: Seo
authors.affiliation: Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Duk L
authors.initials: DL
authors.lastname: Na
authors.affiliation: Department of Neurology, Bobath Memorial Hospital, Seongnam, Korea.
authors.forename: Hae Ri
authors.initials: HR
authors.lastname: Na
authors.affiliation: Department of Neurology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Jae-Hong
authors.initials: JH
authors.lastname: Lee
mesh_terms: D000328:Adult; D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000235:genetics / Q000523:psychology*; D053327:Apolipoprotein E4 / Q000235:genetics; D003071:Cognition; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007723:Korea; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests
chemical_list: D053327:Apolipoprotein E4
keywords: APOE genotype; Alzheimer's disease; early-onset dementia; nulticenter study