Interactional Effects Between Relational and Cognitive Reserves on Decline in Executive Functioning

The present study set out to investigate associations of cognitive reserve (as indicated by education) and relational reserve (as indicated by the family network size and indices of emotional support) to decline in executive functioning over 6 years as measured by changes in Trail Making Test (TMT) completion time in older adults and whether education and network size interacted with age and sex as covariates with respect to this longitudinal association.

We analyzed data from 897 participants tested on TMT parts A and B in two waves 6 years apart. The mean age in the first wave was 74.33 years. Participants reported information on their family networks and their level of education.

Latent change score modeling testing for moderation effects revealed a significant interaction of network size in the first wave of data assessment with education. Specifically, for lower levels of cognitive reserve (-1 SD of education), the longitudinal association between relational reserve in the first wave and subsequent changes in executive functioning was not significant. In contrast, for higher levels of cognitive reserve (+1 SD of education), a higher relational reserve in the first wave significantly predicted a smaller subsequent increase in TMT completion time from the first to the second wave (i.e., a smaller decline in executive functioning).

The present longitudinal study provides evidence for the interaction between cognitive and relational reserves. This confirms the hypothesis that reserves from different domains are intertwined and their combined effects contribute to less cognitive decline in old age.