Jump, Hop, or Skip: Modeling Practice Effects in Studies of Determinants of Cognitive Change in Older Adults

Alexandre Vivot, Melinda C. Power, M. Maria Glymour, Elizabeth R. Mayeda, Andreana Benitez, Avron Spiro, Jennifer J. Manly, Cécile Proust-Lima, Carole Dufouil, Alden L. Gross

Research output: Contribution to journalArticlepeer-review

40 Scopus citations


Improvements in cognitive test scores upon repeated assessment due to practice effects (PEs) are well documented, but there is no empirical evidence on whether alternative specifications of PEs result in different estimated associations between exposure and rate of cognitive change. If alternative PE specifications produce different estimates of association between an exposure and rate of cognitive change, this would be a challenge for nearly all longitudinal research on determinants of cognitive aging. Using data from 3 cohort studies - the Three-City Study-Dijon (Dijon, France, 1999-2010), the Normative Aging Study (Greater Boston, Massachusetts, 1993-2007), and the Washington Heights-Inwood Community Aging Project (New York, New York, 1999-2012) - for 2 exposures (diabetes and depression) and 3 cognitive outcomes, we compared results from longitudinal models using alternative PE specifications: no PEs; use of an indicator for the first cognitive visit; number of prior testing occasions; and square root of the number of prior testing occasions. Alternative specifications led to large differences in the estimated rates of cognitive change but minimal differences in estimated associations of exposure with cognitive level or change. Based on model fit, using an indicator for the first visit was often (but not always) the preferred model. PE specification can lead to substantial differences in estimated rates of cognitive change, but in these diverse examples and study samples it did not substantively affect estimated associations of risk factors with change.

Original languageEnglish (US)
Pages (from-to)302-314
Number of pages13
JournalAmerican journal of epidemiology
Issue number4
StatePublished - Feb 15 2016


  • aging
  • cognitive change
  • longitudinal research
  • practice effects

ASJC Scopus subject areas

  • General Medicine


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