Gerontology 2004;50:17–21 DOI: 10.1159/000074384 Short-Term versus Long-Term Longitudinal Changes in Processing Speed Daniel Zimprich a Scott M. Hofer b Marja J. Aartsen c a Department of Gerontopsychology, University of Zurich, Zurich, Switzerland; b Department of Human Development and Family Studies, Pennsylvania State University, University Park, Pa., USA; c Department of Sociology and Social Gerontology, Free University of Amsterdam, Amsterdam, The Netherlands Daniel Zimprich Department of Gerontopsychology, University of Zürich Schaffhauserstrasse 15 CH–8006 Zürich (Switzerland) Tel. +41 1 635 3232, Fax +41 1 635 3221, E-Mail d.zimprich@psychologie.unizh.ch ABC Fax + 41 61 306 12 34 E-Mail karger@karger.ch www.karger.com © 2004 S. Karger AG, Basel 0304–324X/04/0501–0017$21.00/0 Accessible online at: www.karger.com/ger Key Words Cognitive aging W Nested growth model W Learning W Practice Abstract Background: Previous longitudinal studies of cognitive aging have focused on long-term performance changes. A recent surge of research has demonstrated that there are reliable interindividual differences in short-term cog- nitive performance changes. Objective: The present study links these two pathways of cognitive aging re- search by examining the association between short-term (learning, practice) versus long-term (development) changes in processing speed. Methods: Data from 963 elderly participants come from the Longitudinal Aging Study Amsterdam (LASA). Results: Nested latent growth curve analyses show that the amount of learning or prac- tice in processing speed at first measurement occasion is positively related (r = 0.72) to individual differences in development of processing speed across 6 years. Con- clusions: Short-term learning or practice gains in pro- cessing speed are positively associated with long-term developmental changes in processing speed in the elderly. Copyright © 2004 S. Karger AG, Basel People‘s cognitive performance may vary consider- ably, not only across months or years, i.e., long-term time periods, but also from moment-to-moment, hour-to-hour, day-to-day, i.e., across short-term time periods. Long- term cognitive changes in old age have been the focus of many longitudinal studies, which have demonstrated that, on average, a variety of cognitive abilities decline with aging, but that there are reliable interindividual dif- ferences in rates of intraindividual change [1–3]. Recent- ly, researchers in the field of cognitive aging have identi- fied that the amount of moment-to-moment or day-to-day performance changes in cognitive tasks might also be an indicator of reliable individual differences in old age [4– 6]. Because short-term cognitive performance changes are not always functionally related to time in the sense of growth or decline, but rather represent performance ‘os- cillations’ or ‘fluctuations,’ these studies have used intra- individual performance variability as an index of mo- ment-to-moment or day-to-day cognitive changes. An important extension of previous studies that exam- ined either short-term or long-term cognitive perfor- mance changes consists of investigating the association between these two facets of cognitive change. That is, examining the relationship between cognitive changes based on different time scales, or between ‘microdevelop- ment’ and ‘macrodevelopment’ [7] of cognition in old age. An association between short-term and long-term cogni- tive performance changes would be extremely valuable