Heterogeneity of effects of cognitive reserve on performance in probable Alzheimer’s disease and in subjective cognitive decline.

Abstract

OBJECTIVE:Cognitive reserve (CR) is a term used to describe the adaptability of cognitive processes to brain changes. It helps to explain the differential cognitive adaptation to daily functioning in aging individuals and in individuals with brain pathology, with a higher CR associated with a delay in the manifestation of cognitive symptoms. CR can be estimated using different proxies, such as education, life experience, premorbid IQ, and vocabulary size.Despite the complexity of CR, little research to date has systematically focused on the heterogeneity of its effects. METHOD:We investigated this issue in individuals with probable Alzheimer's disease (AD) and in those with subjective cognitive decline (SCD) by focusing on two variables: 1) the type of CR proxy (i.e., Education and Life-experience); and 2) the type of test used to assess cognitive performance (i.e., the MMSE screening test and the extensive ENB-2 test battery). RESULTS:Our results suggested that effects on CR varied: in individuals with probable AD, we found a positive relationship of Education with performance on both the MMSE and the ENB-2 tests. In contrast, individuals with SCD showed a positive relationship of Life-experience selectively with the ENB-2 global score. CONCLUSIONS:Different proxies can detect different compensatory effects of CR depending on task demand and on an individual's global cognitive condition. In particular, while the Education proxy can capture CR-related cognitive compensation in pathological conditions such as probable AD, the more complex Life-experience proxy might be useful for capturing CR-related effects when signs of cognitive decline are subtle.

M/EEG Dynamics Underlying Reserve, Resilience, and Maintenance in Aging: A Review

“…Their results showed that patients with AD showed increased EEG synchrony in the theta band in frontal and occipital regions compared to patients with SCD. These differences could be explained by the degradation or lower cognitive reserve in patients with AD (Montemurro et al, 2021 ).…”

Cognitive reserve estimated with a life experience questionnaire outperforms education in predicting performance on MoCA: Italian normative data

“…Based on a previous investigation (Montemurro et al, 2021b), in which it has been shown a relevant and selective interaction between Age and a composite life experience CR proxy (but not for Education) in individuals without agerelated disease, an additional analysis was made to further explore such interaction. In line with the variables included in the study, we included in the additional analysis the variable Sex.…”

“…The primary advantage of GAMs over linear regressions is their ability to efficiently treat, through smooth functions, complex non-linear relations between predictors and the dependent variable. GAMs allowed investigating the interaction between continuous variables through tensor surfaces, (something that cannot be handled by GLM); for a recent application of GAM with neuropsychological tests see Yu et al (2020); Montemurro et al (2021b). The reported p values of the GAM analyses are corrected through the Bonferroni method according to the total number of tests performed.…”

“…The CRIq is translated into many languages and it has been used both for clinical and research purposes (Artemiadis et al, 2020;Lavrencic et al, 2018;Lee et al, 2019;Maiovis et al, 2018;Montemurro et al, 2021a;Ozakbas et al, 2021). It has been also shown that, when using CRIq, the effect of CR significantly interacts with age in the expected cognitive performance (Montemurro et al, 2021b); in particular, as age increases performance is typically worse, but not when CRIq score is high. However, it is not clear how the interaction between age and CR may change between another relevant demographic variable, that is sex, which has been shown to have potentially complex interplay with CR (Levine et al, 2021;Myakotnykh et al, 2020;Subramaniapillai et al, 2021).…”

“…Education has the merit of being a practical and easy-to-record measure, but it only captures the formal educational training and at some point it is not effective (Berggren et al, 2018). IQ is also able to estimate CR but it should be used with caution, since not all the IQ measures have the same meaning as proxies of CR (see Nucci et al, 2012;Montemurro et al, 2021b for some considerations about this topic). The CRIq we chose has the advantage of being a validated and standardized measure that does not overlap with IQ (Nucci et al, 2012) and that it can adequately predict the MoCA score (Kang et al, 2018).…”