Measuring Cognition and Cognitive Impairment in the Survey of Health, Ageing and Retirement in Europe (SHARE): A Scoping Review and Instrument Mapping Study

The Survey of Health, Ageing and Retirement in Europe (SHARE) is a cross-national panel study including approximately 160,000 adults aged ≥50 years from 29 countries. While multiple cognitive subtests are available, the SHARE consortium does not currently recommend a standardised approach to cognitive screening. This scoping review and mapping study aimed to (1) assess how cognition is measured in SHARE publications, (2) identify whether any cognitive screening instruments (CSIs) are validated in the SHARE, and (3) explore the potential to replicate additional CSIs using cognitive measures available in recent waves that include an expanded battery of subtests. SHARE-related publications were identified by searching PubMed, and a dedicated online registry of SHARE publications. Methodical details were extracted and quantitative counts calculated. Among 234 SHARE publications, the most common choices were using single subtests (n = 94), CSIs (n = 56), and standardised scores (n = 50). From 22 unique CSIs used in the SHARE, only the SHARE Cognitive Instrument and Langa–Weir Criteria were formally validated. Cognitive impairment was assessed in 36 studies, yet no validated recognised definition of mild cognitive impairment (MCI) was found. Mapping other potential CSIs (n = 81) identified the 10-Point Cognitive Screener, Six-Item Screener and Mini-Cog as other potential CSIs for use across SHARE waves. Further research is needed to validate existing CSIs and to better operationalise MCI in the SHARE.