Harmonisation and Between-Country Differences of the Lifetime of Experiences Questionnaire in Older Adults

Abstract

Background: The Lifetime of Experiences Questionnaire (LEQ) assesses complex mental activity across the life-course and has been associated with brain and cognitive health. The different education systems and occupation classifications across countries represent a challenge for international comparisons. The objectives of this study were four-fold: to adapt and harmonise the LEQ across four European countries, assess its validity across countries, explore its association with brain and cognition and begin to investigate between-country differences in life-course mental activities. Method: The LEQ was administered to 359 cognitively unimpaired older adults (mean age and education: 71.2, 13.2 years) from IMAP and EU-funded Medit-Ageing projects. Education systems, classification of occupations and scoring guidelines were adapted to allow comparisons between France, Germany, Spain and United Kingdom. We assessed the LEQ's (i) concurrent validity with a similar instrument (cognitive activities questionnaire - CAQ) and its structural validity by testing the factors' structure across countries, (ii) we investigated its association with cognition and neuroimaging, and (iii) compared its scores between countries. Results: The LEQ showed moderate to strong positive associations with the CAQ and revealed a stable multidimensional structure across countries that was similar to the original LEQ. The LEQ was positively associated with global cognition. Between-country differences were observed in leisure activities across the life-course. Conclusions: The LEQ is a promising tool for assessing the multidimensional construct of cognitive reserve and can be used to measure socio-behavioural determinants of cognitive reserve in older adults across countries. Longitudinal studies are warranted to test further its clinical utility.

Keywords: cognitive reserve; cross-cultural validation; harmonisation; life-course; lifetime of experiences questionnaire; older adults.

Figure 1

Concurrent validity: scatterplots illustrating the correlation between total LEQ and total CAQ in the whole sample (black) (A) and within each country (France, blue; Germany, green; Spain, yellow; United Kingdom, red) (B). LEQ, Lifetime of Experiences Questionnaire; CAQ, Cognitive Activities Questionnaire; UK, United Kingdom.

Figure 2

Structural validity: Scree plot of the percentage of variance explained by the first five dimensions of the LEQ (A) and loading strength of the LEQ items (unrotated coordinates) on the first dimension (B) in the whole sample (black) and within each country (France, blue; Germany, green; Spain, yellow; United Kingdom, red). Black dashed line is the common threshold eigenvalue of 1 corresponding to 2.6% variance explained (i.e., the eigenvalue divided by 38 items). 13–30, period between 13 and 30 years old; 30–65, period between 30 and 65 years old; 65+, period beyond 65 years old.

Figure 3

Brain and cognitive associations: scatterplot of total LEQ and the Pre-clinical Alzheimer's Cognitive Composite, the grey matter volumes of the hippocampus, and the anterior cingulate cortex at baseline. Raw data (i.e., unadjusted for age and sex) are plotted. Statistical values were adjusted for age and sex. Please note that these analyses were performed in the French Age-well sub-sample because of data availability (n = 135). GM, grey matter; TIV, Total Intracranial Volume.

Figure 4

Between-country differences in education and occupation (A) and leisure activities engagement (B) of the LEQ. Boxplots show the 25th, 50th, and 75th percentiles within each country. Tukey Honestly Significant Difference (HSD) was used as a post hoc test: ^*P < 0.05, ^**P < 0.01, ^***P < 0.001, ^****P < 0.0001. LEQ, Lifetime of Experiences Questionnaire; UK, United Kingdom.