Cognitive processing speed mediates the effects of cardiovascular disease on executive functioning

The goal of this study was to examine the hypothesized mediating role of cognitive processing speed (CPS) in the relationship between cardiovascular disease (CVD) and executive functioning (EF). We investigated whether the processing-speed hypothesis in aging also explains the unique contribution that CPS may have to EF deficits in CVD patients.

A neuropsychological assessment, including multiple measures of CPS and EF, was administered to 21 older adults with a history of CVD and 73 older adults with no history of CVD. Structural equation models were used to measure the indirect associations between CVD and 6 EF task outcomes through a CPS factor. Competing indirect links were assessed using the product-of-coefficients (α*β) approach with bias-corrected bootstrap confidence intervals.

CVD was significantly, negatively related to CPS (β = -.239, 95% CI [-.457, -.021]). CPS was significantly, positively related to an EF composite score (β = .566, 95% CI [.368, .688]). CVD was significantly, negatively related to the EF composite score (β = -.137, 95% CI [-.084, -.211]). The indirect links from CVD to the individual measures of the EF composite score via CPS were all significant. CVD most adversely affected tasks of cognitive flexibility and inhibition indirectly through CPS.

With the present study, we have demonstrated that the processing-speed hypothesis in aging extends to older adult patients with CVD. Reduced CPS significantly underlies the link between CVD status and poorer EF. Individuals with CVD demonstrated poorer CPS and EF than those without CVD, and CPS was specifically implicated as a CVD-related mechanism leading to worse EF. (PsycINFO Database Record