title: Effects of age on time-dependent cognitive change.
abstract: Interpretation of cognitive change has been complicated because different influences on change are not easily distinguished. In this study, longitudinal cognitive change was decomposed into a component related to the length of the interval between test occasions (i.e., time-dependent change) and a component unrelated to the test-retest interval (i.e., time-independent change). Influences of age on the two hypothesized components were investigated in a sample of more than 1,500 adults for whom the intervals between test occasions ranged from less than 1 year to more than 8 years. Although overall change was negatively related to age for all seven composite cognitive variables, little or no effect of age was apparent for the time-dependent component of change. The results suggest that the relations between age and cognitive change over intervals of less than 8 years are largely influenced by factors operating at or near the initial test occasion.
authors.affiliation: Department of Psychology, University of Virginia,Charlottesville, VA 22904-4400, USA. salthouse@virginia.edu
authors.forename: Timothy A
authors.initials: TA
authors.lastname: Salthouse
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D003071:Cognition; D003072:Cognition Disorders / Q000503:physiopathology*; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008875:Middle Aged; D009483:Neuropsychological Tests; D055815:Young Adult