title: Using Robust Normative Data to Investigate the Neuropsychology of Cognitive Aging.
abstract: OBJECTIVE
  The extent to which increasing age is associated with impairment in cognitive function, termed cognitive aging, may have been overestimated in prior studies. The inclusion of individuals with severe or uncontrolled systemic medical illness or prodromal neurodegenerative disease in normal aging samples is likely to bias estimates toward lower cognitive performance and inflate estimates of variability.
  
  
  METHODS
  Unbiased estimates of cognitive aging in 658 adults aged 60-84, who underwent rigorous screening to ensure their general and cognitive health, were computed. The first study screened the psychometric properties of a battery of neuropsychological tests in order to identify those with optimal properties to evaluate cognitive aging. The second study used the selected tests to compare baseline performance within 5-year age bands from 60 to 84.
  
  
  RESULTS
  The first study identified a battery of 12 tests that provided reliable measures of memory, psychomotor speed, attention, and executive function and were appropriate for investigating age-related cognitive changes. The second study observed moderate to large age-related impairment for performance on tests of complex psychomotor function, category fluency, verbal learning, and verbal and visual memory. No, or only small, age effects were observed for working memory, phonemic fluency, learning of visual information, and reaction time.
  
  
  CONCLUSIONS
  These data suggested that while increasing age is associated with impairment in cognitive function, this impairment is less severe and is evident only on more complex neuropsychological tests than estimated previously in samples selected using less rigorous criteria to ensure cognitive health.
authors.affiliation: The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia.|Cooperative Research Centre (CRC) for Mental Health, Carlton South, VIC, Australia.
authors.forename: Karra D
authors.initials: KD
authors.lastname: Harrington
authors.affiliation: The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia.|CogState Ltd., Melbourne, VIC, Australia.
authors.forename: Yen Ying
authors.initials: YY
authors.lastname: Lim
authors.affiliation: Academic Unit for Psychiatry of Old Age, Department of Psychiatry, The University of Melbourne, Parkville, VIC, Australia.|National Ageing Research Institute, Parkville, VIC, Australia.
authors.forename: David
authors.initials: D
authors.lastname: Ames
authors.affiliation: Charles F. and Joanne Knight Alzheimer's Disease Research Center, St. Louis, MO, USA.|Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA.|Department of Psychology, Washington University, St. Louis, MO, USA.
authors.forename: Jason
authors.initials: J
authors.lastname: Hassenstab
authors.affiliation: Centre of Excellence for Alzheimer's Disease Research and Care, School of Exercise, Biomedical and Health Sciences, Edith Cowan University, Perth, WA, Australia.|Sir James McCusker Alzheimer's Disease Research Unit, Hollywood Private Hospital, Nedlands, WA, Australia.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Rainey-Smith
authors.affiliation: The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia.
authors.forename: Joanne
authors.initials: J
authors.lastname: Robertson
authors.affiliation: CSIRO Preventative Health National Research Flagship, The Australian e-Health Research Centre-BioMedIA, Herston, QLD, Australia.
authors.forename: Olivier
authors.initials: O
authors.lastname: Salvado
authors.affiliation: The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia.
authors.forename: Colin L
authors.initials: CL
authors.lastname: Masters
authors.affiliation: The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia.|CogState Ltd., Melbourne, VIC, Australia.
authors.forename: Paul
authors.initials: P
authors.lastname: Maruff
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000523:psychology*; D001288:Attention / Q000502:physiology; D001315:Australia; D000066492:Cognitive Aging; D056344:Executive Function / Q000502:physiology; D005260:Female; D006801:Humans; D007858:Learning / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011594:Psychometrics; D011597:Psychomotor Performance / Q000502:physiology; D012016:Reference Values
keywords: Assessment; Elderly/geriatrics/aging; Executive functions; Fluency (verbal/nonverbal); Learning and memory; Norms/normative studies