Carolien Zeetsen

33 CHAPTER Psychometric properties of the MoCA in healthy participants 2 Data sets from three smaller studies were combined. In the first study, the NART and MoCA version 7.1 were administered in 34 participants. In the second study, MoCA version 7.1 and 7.2 were administered in this fixed order in 74 participants. In the third study, 103 participants completed the NART, and two versions of the MoCA were administered in a counterbalanced order: MoCA version 7.1 and 7.2 (51 participants), and MoCA version 7.1 and 7.3 (52 participants). Analyses Participant characteristics and Montreal Cognitive Assessment scores The participant characteristics for age, age category (for which age was categorised into two groups, i.e. 18–54 and 55–70 years), sex, educational level and estimated premorbid intelligence are presented for the total sample. Next, a description of MoCA scores on all items, and the mean MoCA–TS, –DS and –MIS were provided for each version. Demographic factors In the analyses examining the influence of demographic factors on MoCA performance, only participants were included in whom MoCA version 7.1 was administered first, eliminating possible learning effects. The influence of age, educational level and estimated premorbid intelligence on MoCA–TS and –MIS were determined using Pearson’s correlations or Spearman’s rho (if assumptions of normality were not met). The influence of sex and age category on MoCA–TS was determined using independent t –tests and to determine the influence of these variables on MoCA–MIS, Mann–Whitney tests were used. Systematic differences The equivalence of the MoCA versions was determined by using all participants in whom MoCA 7.1 and one of the alternate versions were administered in a counterbalanced order, to reduce the chances of the order of administration adversely influencing the results. Equivalence was determined for the MoCA–TS, –DS, –MIS and for each item by examining possible systematic differences using Wilcoxon signed–rank two–related–samples tests or McNemar’s test (for all dichotomous scores). Test–retest reliability The test–retest reliability was determined using all participants in whom administration of MoCA 7.1 was followed by one of the alternate versions. By using two–way mixed intra–class correlations (ICC) with absolute agreement, the test–retest reliability for the MoCA–TS, –DS, –MIS and each item was determined. An ICC of less than 0.40 is indicative of poor reliability, between 0.40 and 0.59 is considered fair, between 0.60 and 0.74 good, and an ICC of 0.75 and above indicates excellent reliability (Cicchetti, 1994). All data were computed and analysed with IBM SPSS version 25.0.