title: Unconditional and Conditional Standards Using Cognitive Function Curves for the Modified Mini-Mental State Exam: Cross-Sectional and Longitudinal Analyses in Older Chinese Adults in Singapore.
abstract: OBJECTIVE
  The conventional practice of assessing cognitive status and monitoring change over time in older adults using normative values of the Mini-Mental State Exam (MMSE) based on age bands is imprecise. Moreover, population-based normative data on changes in MMSE score over time are scarce and crude because they do not include age- and education-specific norms. This study aims to develop unconditional standards for assessing current cognitive status and conditional standards that take prior MMSE score into account for assessing longitudinal change, with percentile curves as smooth functions of age.
  
  
  METHODS
  Cross-sectional and longitudinal data of a modified version of the MMSE for 2,026 older Chinese adults from the Singapore Longitudinal Aging Study, aged 55-84, in Singapore were used to estimate quantile regression coefficients and create unconditional standards and conditional standards.
  
  
  RESULTS
  We presented MMSE percentile curves as a smooth function of age in education strata, for unconditional and conditional standards, based on quantile regression coefficient estimates. We found the 5th and 10th percentiles were more strongly associated with age and education than were higher percentiles. Model diagnostics demonstrated the accuracy of the standards.
  
  
  CONCLUSIONS
  The development and use of unconditional and conditional standards should facilitate cognitive assessment in clinical practice and deserve further studies.
authors.affiliation: Centre for Quantitative Medicine, Duke-National University of Singapore Graduate Medical School, Singapore; Department of International Health, University of Tampere, Finland.
authors.forename: Yin Bun
authors.initials: YB
authors.lastname: Cheung
authors.affiliation: Centre for Quantitative Medicine, Duke-National University of Singapore Graduate Medical School, Singapore.
authors.forename: Ying
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Gerontology Research Programme, Department of Psychological Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
authors.forename: Lei
authors.initials: L
authors.lastname: Feng
authors.affiliation: Gerontology Research Programme, Department of Psychological Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
authors.forename: Liang
authors.initials: L
authors.lastname: Feng
authors.affiliation: Gerontology Research Programme, Department of Psychological Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
authors.forename: Ma Shwe Zin
authors.initials: MS
authors.lastname: Nyunt
authors.affiliation: Institute of Geriatrics and Active Ageing and Department of Geriatric Medicine, Tan Tock Seng Hospital, Singapore.
authors.forename: Mei Sian
authors.initials: MS
authors.lastname: Chong
authors.affiliation: Institute of Geriatrics and Active Ageing and Department of Geriatric Medicine, Tan Tock Seng Hospital, Singapore.
authors.forename: Wee Shiong
authors.initials: WS
authors.lastname: Lim
authors.affiliation: Neuroscience and Behavioral Disorders Program, Duke-National University of Singapore Graduate Medical School, Singapore.
authors.forename: Tih Shih
authors.initials: TS
authors.lastname: Lee
authors.affiliation: Department of Geriatric Medicine, Khoo Teck Puat Hospital, Singapore.
authors.forename: Philip
authors.initials: P
authors.lastname: Yap
authors.affiliation: Department of Geriatric Medicine, Alexandra Hospital, Singapore.
authors.forename: Keng Bee
authors.initials: KB
authors.lastname: Yap
authors.affiliation: Gerontology Research Programme, Department of Psychological Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore. Electronic address: pcmngtp@nus.edu.sg.
authors.forename: Tze Pin
authors.initials: TP
authors.lastname: Ng
mesh_terms: D000368:Aged; D000375:Aging / Q000523:psychology*; D044466:Asian People / Q000523:psychology*; D003071:Cognition; D003430:Cross-Sectional Studies; D005260:Female; D015577:Geriatric Assessment / Q000379:methods*; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales / Q000592:standards*; D012015:Reference Standards; D012846:Singapore
keywords: Cognitive function; Mini-Mental State Exam; cognitive impairment; norms