title: Factors associated with improvement or decline in cognitive function after an ischemic stroke in Korea: the Korean stroke cohort for functioning and rehabilitation (KOSCO) study.
abstract: BACKGROUND
  We conducted a prospective cohort study to investigate prevalence of poststroke cognitive impairment at 3 and 12 months after stroke onset and identify clinical and demographic factors associated with improvement or decline in cognitive function between 3 months and 12 months.
  
  
  METHODS
  We analyzed the cognitive assessments of total patients and patients older than 65 years separately. All patients with an ischemic stroke were divided into normal cognitive group (NCG) and impaired cognition group (ICG) by using a cutoff score on the Korean Mini-Mental State Examination (K-MMSE). Patients were additionally classified into 3 subgroups according to the changes in their K-MMSE scores between 3 and 12 months: Stable group with K-MMSE scores changes ranging from -2 to +2 points (-2 ≤ △MMSE ≤ +2); converter group with increase more than 3 points (3 ≤ △MMSE); and reverter group with decrease more than 3 points (-3 ≤ △MMSE). We also analyzed factors affecting cognitive change from 3 months to 12 months among the 3 groups including baseline medical record, stroke and treatment characteristics, and various functional assessments after 3 months.
  
  
  RESULTS
  This study included 2,625 patients with the first time ischemic stroke. Among these patients, 1,735 (66.1%) were classified as NCG, while 890 patients (33.9%) were belonged to the ICG at 3 month. Within the NCG, 1,460 patients (82.4%) were stable group, 93 patients (5.4%) were converter group, and 212 patients (12.2%) were reverter group at 12 months onset. Within the ICG group, 472 patients (53.0%) were stable group, 321 patients (36.1%) were converter group, and 97 patients (10.9%) were reverter group. When different factors were investigated, the three subgroups in NCG and ICG showed significant different factors affecting cognitive function from 3 to 12 month.
  
  
  CONCLUSIONS
  The prevalence of cognitive impairment showed difference between 3,12 months. To analyze the cognitive change from 3 month to 12 month, the proportion stable group was dominant in NCG and converter group was higher in ICG. By investigating the influencing factors from each group, we were able to identify the predictors including the age factor.
authors.affiliation: Department of Rehabilitation Medicine, Pusan National University School of Medicine, Research Institute of Convergence for Biomedical Science and Technology, 20, Geumo-ro, Mulgeum, Yangsan, 626-770, South Korea.
authors.forename: Jin A
authors.initials: JA
authors.lastname: Yoon
authors.affiliation: Department and Research Institute of Rehabilitation Medicine, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 120-752, Republic of Korea.
authors.forename: Deog Young
authors.initials: DY
authors.lastname: Kim
authors.affiliation: Department of Rehabilitation Medicine, School of Medicine, Chungnam National University, 282 Munhwa-ro, Jung-gu, Daejeon, 301-721, Republic of Korea.
authors.forename: Min Kyun
authors.initials: MK
authors.lastname: Sohn
authors.affiliation: Department of Rehabilitation Medicine, Konkuk University School of Medicine, 120-1 Neungdong-ro, Hwayang-dong, Gwangjin-gu, Seoul, 143-729, Republic of Korea.
authors.forename: Jongmin
authors.initials: J
authors.lastname: Lee
authors.affiliation: Department of Physical and Rehabilitation Medicine, Chonnam National University Medical School, 42 Jebong-ro, Donggu, Gwangju, 501-757, Republic of Korea.
authors.forename: Sam-Gyu
authors.initials: SG
authors.lastname: Lee
authors.affiliation: Department of Rehabilitation Medicine, Kyung-pook National University College of Medicine, 130 Dongdeok-ro, Jung-gu, Daegu, 700-721, Republic of Korea.
authors.forename: Yang-Soo
authors.initials: YS
authors.lastname: Lee
authors.affiliation: Department of Rehabilitation Medicine, Jeju University Hospital, University of Jeju College of Medicine, 15 Aran 13-gil, Jeju, 690-767, Republic of Korea.
authors.forename: Eun Young
authors.initials: EY
authors.lastname: Han
authors.affiliation: Department of Rehabilitation Medicine, Wonkwang University School of Medicine, 895 Muwang-ro, Iksan, Jeonlabuk-do, 570-711, Republic of Korea.
authors.forename: Min Cheol
authors.initials: MC
authors.lastname: Joo
authors.affiliation: Department of Rehabilitation Medicine, Wonkwang University School of Medicine, 895 Muwang-ro, Iksan, Jeonlabuk-do, 570-711, Republic of Korea.
authors.forename: Gyung-Jae
authors.initials: GJ
authors.lastname: Oh
authors.affiliation: Research And Statistical Support, Research Institute of Convergence for Biomedical Science and Technology, Pusan National University Yangsan Hospital, 20, Geumo-ro, Mulgeum-eu, Yangsan, 626-770, South Korea.
authors.forename: Junhee
authors.initials: J
authors.lastname: Han
authors.affiliation: Department of Rehabilitation Medicine, Pusan National University School of Medicine, Research Institute of Convergence for Biomedical Science and Technology, 20, Geumo-ro, Mulgeum, Yangsan, 626-770, South Korea.
authors.forename: Minsu
authors.initials: M
authors.lastname: Park
authors.affiliation: Department of Neurology, Pusan National University College of Medicine, Pusan National University Yangsan Hospital, 20, Geumo-ro, Mulgeum-eu, Yangsan, 626-770, South Korea.
authors.forename: Kyung Pil
authors.initials: KP
authors.lastname: Park
authors.affiliation: Department of Neurology, Pusan National University College of Medicine, Pusan National University Yangsan Hospital, 20, Geumo-ro, Mulgeum-eu, Yangsan, 626-770, South Korea.
authors.forename: Kyung-Ha
authors.initials: KH
authors.lastname: Noh
authors.affiliation: Department of Physical and Rehabilitation Medicine, Center for Prevention and Rehabilitation, Heart Vascular and Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Ilwon-dong, Gangnam-gu, Seoul, 135-710, Republic of Korea.
authors.forename: Won Hyuk
authors.initials: WH
authors.lastname: Chang
authors.affiliation: Department of Rehabilitation Medicine, Pusan National University School of Medicine, Research Institute of Convergence for Biomedical Science and Technology, 20, Geumo-ro, Mulgeum, Yangsan, 626-770, South Korea. rmshin@pusan.ac.kr.|Department of Rehabilitation Medicine, Pusan National University School of Medicine, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, 20, Geumo-ro, Mulgeum, Yangsan, 626-770, South Korea. rmshin@pusan.ac.kr.
authors.forename: Yong-Il
authors.initials: YI
authors.lastname: Shin
authors.affiliation: Department of Physical and Rehabilitation Medicine, Center for Prevention and Rehabilitation, Heart Vascular and Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Ilwon-dong, Gangnam-gu, Seoul, 135-710, Republic of Korea. yunkim@skku.edu.
authors.forename: Yun-Hee
authors.initials: YH
authors.lastname: Kim
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003071:Cognition; D003072:Cognition Disorders / Q000175:diagnosis / Q000209:etiology*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011446:Prospective Studies; D056910:Republic of Korea; D020521:Stroke / Q000150:complications* / Q000453:epidemiology
keywords: Cognition; Inverter; Ischemic stroke; Reverter; Risk factors