title: Evaluation of a research diagnostic algorithm for DSM-5 neurocognitive disorders in a population-based cohort of older adults.
abstract: BACKGROUND
  There is little information on the application and impact of revised criteria for diagnosing dementia and mild cognitive impairment (MCI), now termed major and mild neurocognitive disorders (NCDs) in the DSM-5. We evaluate a psychometric algorithm for diagnosing DSM-5 NCDs in a community-dwelling sample, and characterize the neuropsychological and functional profile of expert-diagnosed DSM-5 NCDs relative to DSM-IV dementia and International Working Group criteria for MCI.
  
  
  METHODS
  A population-based sample of 1644 adults aged 72-78 years was assessed. Algorithmic diagnostic criteria used detailed neuropsychological data, medical history, longitudinal cognitive performance, and informant interview. Those meeting all criteria for at least one diagnosis had data reviewed by a neurologist (expert diagnosis) who achieved consensus with a psychiatrist for complex cases.
  
  
  RESULTS
  The algorithm accurately classified DSM-5 major NCD (area under the curve (AUC) = 0.95, 95% confidence interval (CI) 0.92-0.97), DSM-IV dementia (AUC = 0.91, 95% CI 0.85-0.97), DSM-5 mild NCD (AUC = 0.75, 95% CI 0.70-0.80), and MCI (AUC = 0.76, 95% CI 0.72-0.81) when compared to expert diagnosis. Expert diagnosis of dementia using DSM-5 criteria overlapped with 90% of DSM-IV dementia cases, but resulted in a 127% increase in diagnosis relative to DSM-IV. Additional cases had less severe memory, language impairment, and instrumental activities of daily living (IADL) impairments compared to cases meeting DSM-IV criteria for dementia. DSM-5 mild NCD overlapped with 83% of MCI cases and resulted in a 19% increase in diagnosis. These additional cases had a subtly different neurocognitive profile to MCI cases, including poorer social cognition.
  
  
  CONCLUSIONS
  DSM-5 NCD criteria can be operationalized in a psychometric algorithm in a population setting. Expert diagnosis using DSM-5 NCD criteria captured most cases with DSM-IV dementia and MCI in our sample, but included many additional cases suggesting that DSM-5 criteria are broader in their categorization.
authors.affiliation: Centre for Research on Ageing, Health and Wellbeing, Research School of Population Health, College of Medicine, Biology and Environment, Australian National University, 54 Mills Road, ACT, 0200, Canberra, Australia. ranmalee.eramudugolla@anu.edu.au.
authors.forename: Ranmalee
authors.identifier: http://orcid.org/0000-0001-5097-8267
authors.initials: R
authors.lastname: Eramudugolla
authors.affiliation: Centre for Research on Ageing, Health and Wellbeing, Research School of Population Health, College of Medicine, Biology and Environment, Australian National University, 54 Mills Road, ACT, 0200, Canberra, Australia.
authors.forename: Moyra E
authors.initials: ME
authors.lastname: Mortby
authors.affiliation: Neuropsychiatric Institute, Prince of Wales Hospital, and Centre for Healthy Brain Ageing (CHeBA), School of Psychiatry, University of New South Wales, Sydney, Australia.
authors.forename: Perminder
authors.initials: P
authors.lastname: Sachdev
authors.affiliation: Centre for Research on Ageing, Health and Wellbeing, Research School of Population Health, College of Medicine, Biology and Environment, Australian National University, 54 Mills Road, ACT, 0200, Canberra, Australia.
authors.forename: Chantal
authors.initials: C
authors.lastname: Meslin
authors.affiliation: Centre for Research on Ageing, Health and Wellbeing, Research School of Population Health, College of Medicine, Biology and Environment, Australian National University, 54 Mills Road, ACT, 0200, Canberra, Australia.|Academic Unit of Psychiatry and Addiction Medicine, College of Medicine, Biology and Environment, Australian National University, Canberra, Australia.
authors.forename: Rajeev
authors.initials: R
authors.lastname: Kumar
authors.affiliation: Centre for Research on Ageing, Health and Wellbeing, Research School of Population Health, College of Medicine, Biology and Environment, Australian National University, 54 Mills Road, ACT, 0200, Canberra, Australia.
authors.forename: Kaarin J
authors.initials: KJ
authors.lastname: Anstey
mesh_terms: D000368:Aged; D000465:Algorithms; D015331:Cohort Studies; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D003943:Diagnostic Techniques, Neurological; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D006801:Humans; D008297:Male; D019965:Neurocognitive Disorders / Q000145:classification / Q000000981:diagnostic imaging* / Q000523:psychology; D011594:Psychometrics / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
keywords: Cognitive aging; DSM-5; Diagnostic algorithm; Longitudinal; Mild cognitive impairment; Neurocognitive disorders; dementia