The objective of this
research is to investigate the validity of a structural model of cognitive
reserve (CR) capacity and cognitive decline. Active models of CR highlight
the brain’s ability to use pre-existing cognitive processes or enlist
compensatory processes (Stern, 2002), in the face of mental challenge.
The proposed CR model is comprised of Executive Function/Processing
Resources (EF/PR) and Cognitive Activity (CA). The aim of the present
study was to test this model of predictive relationships between baseline
CR and global cognition/memory outcomes in two longitudinal cohorts,
Dutch and Irish, at 6-year and 2-year follow-up, respectively. Analysis
was conducted on the Maastricht Ageing Study (n=1587), and the Irish
Longitudinal Study on Ageing (n=4512). Structural equation modelling
(WLSMV estimation) investigated relationships between CR capacity,
memory and cognitive performance in two age groups: 50-64 years and
65-82 years. Results indicate that overall the structural model fits the data
at just reasonable level for the Dutch dataset and very well for the Irish
dataset (Dutch 50-64/65-82 age-groups, respectively: RMSEA=.071[.059-
.083]/.075[.063-.087]; CFI=.923/.888. Irish 50-64/65-82 age-groups, respectively:
RMSEA=.044[.039-.049]/.041[.036-.047]; CFI=.964/.968). Parameter
estimates across both datasets indicate a strong relationship between the
two CR factors in both age groups (covariance range: 0.59 - 0.82). In all
models EF/PR was a predictor of MMSE (standardized regression coefficient
range: .325 - .386, p<.01). Investigating structure and fit of the CR
model in both Dutch and Irish contexts has provided evidence for the validity
of the two-factor CR capacity model and its predictive relationship with
cognitive outcomes.