A relação entre a reserva cognitiva e o estado cognitivo no envelhecimento normal

Abstract

Theoretical Background: Healthy older adults tend to perform worse than younger people in certain cognitive tasks. However, there is some inter-individual variability when it comes to cognitive decline with age. The Cognitive Reserve (CR) model holds that differences in cognitive processing and neural compensation mechanisms mean that some people can deal better with cognitive aging than others. Education, professional occupation and leisure activities are believed to contribute towards CR. CR is related to a better cognitive performance. The Cognitive Reserve Index questionnaire (CRIq) is a new instrument for measuring CR accumulated throughout an individual’s lifespan. This study aimed to explore the relationship between CR and the cognitive mechanisms of aging in older adults and to determine whether the CRIq is an adequate measure of CR. Method: A convenience sample of 39 cognitively healthy, 65-86 year old individuals, with no relevant history of psychiatric or neurologic disease, took part in this cross-sectional study. Each subject completed the Digit-Symbol substitution test, the backwards Digit Span and the Stroop test. A brief clinical interview was also carried out. Pearson correlation coefficient test and linear regressions were used. Results: Age only correlated (negatively) with Digit-Symbol scores. The Cognitive Reserve Index (CRI) showed a positive correlation with Digit-Symbol and backwards Digit Span scores but not with the Stroop Interference Index. A multiple linear regression showed that the IRC, but not education, was able to predict subjects’ performance in processing speed and working memory tasks. Discussion: Conceptually, the CRIq seems to be a useful tool to assess CR in an objective manner, gathering information relative to an individual’s lifespan, as opposed to other tools that only consider current lifestyles. Furthermore, the CRI allows for comparisons between different ages. We believe its validation in Portugal would be an important contribution towards making the assessment of CR more systematic. However, its relevance in clinical settings should be further explored and discussed since its administration requires a considerable amount of time and effort for the examinee. Moreover, we found that aging is not necessarily accompanied by a decline in cognitive function. CR as measured by the CRIq seems to have a protective effect that cannot be explained by education alone, for which reason we conclude that other factors such as professional occupation and participation in leisure activities seem to contribute towards explaining differences in cognitive performance. These results reinforce the need to consider other factors besides education when promoting active aging.

Date of Award	8 Jun 2015
Original language	Portuguese
Awarding Institution	Universidade Católica Portuguesa
Supervisor	Maria Vânia Silva Nunes (Supervisor) & Amélia Simões Figueiredo (Co-Supervisor)