Lower practice effects as a marker of cognitive performance and dementia risk: A literature review

BACKGROUND: Practice effects (PEs) are improvements in performance after repeated exposure to test materials, and typically viewed as a source of bias in repeated cognitive assessments. We aimed to determine whether characterizing PEs could also provide a useful marker of early cognitive decline. METHODS: We conducted a systematic review of the literature, searching PsycInfo (Ebsco) and PubMed databases for articles studying PEs in aging and dementia populations. Articles published between 1920 and 2019 were included. RESULT: We identified 259 articles, of which 27 studied PEs as markers of cognitive performance. These studies consistently showed that smaller, less‐robust PEs were associated with current diagnostic status and/or future cognitive decline. In addition, lower PEs were associated with Alzheimer's disease risk factors and neurodegeneration biomarkers. CONCLUSION: PEs provide a potentially useful marker of cognitive decline, and could prove valuable as part of a cost‐effective strategy to select individuals who are at‐risk for dementia for future interventions.