Cognitive reserve protects executive function in older adults

SAN DIEGO — Cognitive reserve acted as a protective factor that preserved executive function in older adults with benefits mitigated by depression level, according to a presentation at the Alzheimer’s Association International Conference.

“Cognitive reserve operates as a protective mechanism on cognitive performance,” Loredana Frau, of the school of psychology at Liverpool John Moores University in the U.K., said during her presentation.

Frau and colleagues sought to examine the relationship between cognitive reserve, depression and executive function in older adults over a 10-year period.

Their longitudinal study involved 416 individuals (290 cognitively stable [CUS], 97 cognitively unimpaired declining [CUD] and 29 with mild cognitive impairment [MCI]) from the Wisconsin Registry for Alzheimer’s Prevention dataset. Participants were screened for cognitive reserve via the Wide Range Achievement Test (WRAT-4), for depression by the Center for Epidemiologic Studies Depression Scale (CES-D), for executive functions by CFL, Digit Span and number sequencing tests. Screening for the APOE e4 gene was done through blood analysis. Hierarchical linear regression, controlling for age, gender, APOE and diagnosis (CUS, CUD, MCI) in model 1, cognitive reserve and depression in model 2 and CR-depression interaction in model 3 were performed. Multinomial logistic regression was utilized to predict conversion to CUD and MCI from a healthy baseline (CUS).

Results showed that, over the 10-year follow-up interval, cognitive reserve acted as a protective factor that preserved executive function; however, the beneficial effect of cognitive reserve on executive function was linked to mitigation of increasing symptoms of depression. In addition, data revealed that level of depression predicted a changeover from CUS to CUD, but depression and APOE e4 best predicted a conversion from CUS to MCI.

“These studies can be very important to analyze different proxies of cognitive reserve or motor disorders,” Frau stated in the presentation.