Inverse relationship between the evans index and cognitive performance in non-disabled, stroke-free, community-dwelling older adults. A population-based study

Abstract

Objective: The Evans Index (EI) is used for recognition of individuals with normal pressure hydrocephalus. However, recent studies suggest that the EI is not a reliable marker of this condition. Rather, the EI may be inversely correlated with cognitive performance, but information on this correlation is lacking. We aimed to assess the relationship between the EI and cognitive performance in community-dwelling older adults.

Patients and methods: The study included 314 non-disabled, stroke-free, individuals aged ≥60 years enrolled in the Atahualpa Project undergoing brain MRI and MoCA testing. Using generalized linear models, adjusted for demographics, cardiovascular risk factors edentulism, depression, global cortical atrophy and white matter hyperintensities of vascular origin, we assessed the relationship between the EI and cognitive performance. Predictive margins of the MoCA score according to percentiles of the EI were also evaluated, after adjusting for variables reaching significance in univariate models.

Results: The mean EI was 0.248 ± 0.022 and the mean MoCA score was 19.7 ± 4.8 points. A fully-adjusted generalized linear model showed a significant inverse relationship between the EI and the MoCA score. Predictive models showed a decrease in the MoCA score according to increased levels of the EI (β: -3.28; 95% C.I.: -6.09 to -0.47; p = 0.022).

Conclusion: The independent effect of the EI on the MoCA score provides evidence of the utility of the EI to evaluate cognitive performance.

Keywords: Cognitive performance; Evans index; Montreal cognitive assessment; Population-Based study.