title: Further analyses of the effects of practice, dropout, sex, socio-economic advantage, and recruitment cohort differences during the University of Manchester longitudinal study of cognitive change in old age.
abstract: A sample of 4,314 volunteers who, when first recruited, were aged from 41 to 93 years were quadrennially tested from 2 to 4 occasions during the next 4 to 20 years on the Cattell Culture Fair intelligence test, 2 tests of information-processing speed, the Wechsler Adult Intelligence Scale (WAIS) vocabulary test, and 3 memory tests. After significant effects of practice, sex, demographics, socio-economic advantage, and recruitment cohort had been identified and considered, performance on all tests declined with age. These age-related declines accelerated for the Cattell and WAIS, 2 tests of information speed, and 2 of the memory tests. For all tests individuals' trajectories of age-related change diverged with increasing age but, unexpectedly, were not affected by demographic factors. Practice gains from an initial experience of the cognitive tests remained undiminished as the interval before the second experience increased from 4 to 8 + years.
authors.affiliation: Department of Psychology, University of Oxford, Oxford, UK. patrick.rabbitt@psy.ox.ac.uk
authors.forename: Patrick
authors.initials: P
authors.lastname: Rabbitt
authors.forename: Mary
authors.initials: M
authors.lastname: Lunn
authors.forename: Said
authors.initials: S
authors.lastname: Ibrahim
authors.forename: Lynn
authors.initials: L
authors.lastname: McInnes
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology / Q000523:psychology; D015331:Cohort Studies; D003710:Demography; D004522:Educational Status; D005260:Female; D015577:Geriatric Assessment; D006801:Humans; D007360:Intelligence / Q000502:physiology*; D007361:Intelligence Tests; D008297:Male; D008606:Mental Processes / Q000502:physiology*; D008875:Middle Aged; D015233:Models, Statistical; D009483:Neuropsychological Tests; D010352:Patient Dropouts; D011214:Practice, Psychological; D012189:Retrospective Studies; D012727:Sex Characteristics; D012959:Socioeconomic Factors