Instruments to Assess Cognitive Reserve Among Older Adults: a Systematic Review of Measurement Properties

Cognitive reserve explains the differences in the susceptibility to cognitive impairment related to brain aging, pathology, or insult. Given that cognitive reserve has important implications for the cognitive health of typically and pathologically aging older adults, research needs to identify valid and reliable instruments for measuring cognitive reserve. However, the measurement properties of current cognitive reserve instruments used in older adults have not been evaluated according to the most up-to-date COnsensus-based Standards for the selection of health status Measurement INstruments (COSMIN). This systematic review aimed to critically appraise, compare, and summarize the quality of the measurement properties of all existing cognitive reserve instruments for older adults. A systematic literature search was performed to identify relevant studies published up to December 2021, which was conducted by three of four researchers using 13 electronic databases and snowballing method. The COSMIN was used to assess the methodological quality of the studies and the quality of measurement properties. Out of the 11,338 retrieved studies, only seven studies that concerned five instruments were eventually included. The methodological quality of one-fourth of the included studies was doubtful and three-seventh was very good, while only four measurement properties from two instruments were supported by high-quality evidence. Overall, current studies and evidence for selecting cognitive reserve instruments suitable for older adults were insufficient. All included instruments have the potential to be recommended, while none of the identified cognitive reserve instruments for older adults appears to be generally superior to the others. Therefore, further studies are recommended to validate the measurement properties of existing cognitive reserve instruments for older adults, especially the content validity as guided by COSMIN.Systematic Review Registration numbers: CRD42022309399 (PROSPERO).

The Assessment of Cognitive Reserve: A Systematic Review of the Most Used Quantitative Measurement Methods of Cognitive Reserve for Aging

The cognitive reserve (CR) is widely accepted as the active ability to cope with brain damage, using preexisting cognitive and compensatory processes. The common CR proxies used are the number of formal years of education, intelligence quotient (IQ) or premorbid functioning, occupation attainment, and participation in leisure activities. More recently, it has employed the level of literacy and engagement in high-level cognitive demand of professional activities. This study aims to identify and summarize published methodologies to assess the CR quantitatively. We searched for published studies on PubMed, ScienceDirect, and Web of Science between September 2018 and September 2021. We only included those studies that characterized the CR assessment methodology. The search strategy identified 1,285 publications, of which 25 were included. Most of the instruments targeted proxies individually. The lack of a gold standard tool that incorporates all proxies and cognitive tests highlights the need to develop a more holistic battery for the quantitative assessment of CR. Further studies should focus on a quantitative methodology that includes all these proxies supported by normative data to improve the use of CR as a valid measure in clinical contexts.

The Lifetime of Experiences Questionnaire: Psychometric Properties and Relationships With Memory Function in an Iranian Elderly Sample

This study aimed to validate the Persian version of the Lifetime of Experiences Questionnaire (LEQ) and examine the relationship between life experience and memory function. To this end, two studies were conducted. Study one examined the factor structure, internal consistency, and convergent and discriminant validity of the Persian version of LEQ with 247 healthy elderly individuals (M age = 70.17, SD = 4.42; 55.9% women). The exploratory factor analysis yielded a five-factor solution, including Knowledge, Physical, Socialization, Artistic, and Leisure dimensions, which accounted for 42.42% of the explained variance. The internal consistency of the LEQ was in the acceptable range (α = 0.703). Also, the LEQ and its subscales (except the Artistic subscale) had a negative relationship with geriatric depression and a positive relationship with a healthy lifestyle, supporting the measure's convergent and discriminant validity. In the second study, we examined the relationship between LEQ (total and subscales score) and memory function using Pearson correlation and moderating analysis with 149 participants (M age = 70.37, SD = 4.29; 55.03% women). The results demonstrated that the LEQ total and subscales scores correlated positively with episodic memory. In the same vein, LEQ total score and Knowledge subscale showed a positive correlation with semantic memory. The results of moderation analysis showed that LEQ subscales have a different role in memory decline. The knowledge subscale as a content component moderates the effect of age on semantic memory (B = 0.005, t = 2.021, p = 0.045), while the mid-life non-specific activities, which are based on life stages, moderate the effect of age on episodic memory (B = 0.007, t = 3.348, p = 0.001). In conclusion, our results indicated that the Persian version of the LEQ is a valid and reliable instrument for measuring experiences and activities throughout life, which can be used in professional clinical and research settings in the aging context with Iranian elderly samples. Furthermore, our findings suggest that various life experiences can be considered cognitive reserves in old age.

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

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.