Carolien Zeetsen

30 With respect to alternate–form reliability, relevant for repeated assessment in individuals with the aim to overcome material–specific learning effects, Chertkow et al. (2011) developed two alternate versions of the original version (MoCA alternate versions 7.2 and 7.3). The alternate versions have been translated into nearly 40 languages, including Dutch. The MoCA Total Score (MoCA–TS) of the English, French and several other translations was found to be systematically equivalent across versions (Chertkow et al., 2011; Nasreddine & Patel, 2016). However, looking at item level one study in geriatric patients showed systematic differences between the original and both alternate versions for the items figure copy, animal naming and abstract reasoning (Lebedeva et al., 2016), but studies in healthy individuals are lacking. Finally, the test–retest and inter–rater reliability are important for repeated assessments. The test–retest reliability of the English–language versions, and the German and Czech translations of MoCA 7.1 and 7.2 range from 0.42 to 0.81, for MoCA–TS (Costa et al., 2012; Feeney et al., 2016; Kopecek, Bezdicek, et al., 2017; Wu et al., 2017). The lowest reliability was found after an administration interval of three years (Kopecek, Bezdicek, et al., 2017). The inter–rater reliability of the items alternating trail making, figure copy and clock drawing of MoCA version 7.1 was recently investigated in a large multicentre trial, including 1119 participants (Cumming et al., 2020). Kappa coefficients ranging from 0.46 (hands of the clock) to 0.94 (alternating trail making) were found, where a higher coefficient means better agreement between raters. As can be seen from this overview, differences in MoCA properties exist between populations and translations, and mixed results have been found for participants with different sociodemographic characteristics. As the MoCA is increasingly being administered to individuals younger than 50, it is important to determine the psychometric properties of the Dutch translations of the MoCA in a wide age range. The aims of the current study are, therefore, to assess psychometric properties of the MoCA in healthy participants. We will investigate: 1) whether demographic variables such as age, sex, educational level and estimated premorbid intelligence are associated with performance on the MoCA; 2) whether systematic differences between MoCA version 7.1 and alternate versions 7.2 or 7.3 can be found and 3) what the test–retest reliability between MoCA version 7.1, and alternate versions 7.2 and 7.3 is.