Development and validation of elderly cognitive reserve scale

Cognitive reserve has been created to explain individual differences in vulnerability to brain changes and differences in the occurrence of clinical symptoms. The purpose of this study was to develop and validate a tool to measure the cognitive reserve of the elderly and compare it in two healthy and mild cognitive impairment groups.

The research method was survey and causal-comparative. After studying the theoretical foundations of cognitive reserve and available tools, the desired scale was created and its face and content validity were reviewed and approved by four geriatricians. This scale was performed on 100 elderly people (female=53, male=47) with a mean age of (68.23±6.30) selected by the available sampling method in 2019. Reliability was assessed by Cronbach's alpha coefficient and the retest method. Validity was tested by concurrent validity (correlation) and diagnostic validity (discriminant analysis). The correlations of subscales with each other and with the total score were also calculated. Finally, the difference between the two groups (independent t-test) and the prediction of cognitive status (multiple regression) were also examined.

The results showed the Cronbach's alpha coefficient of α=0.623, retest reliability of 0.839, concurrent validity of 0.616 with cognitive reserve index questionnaire, diagnostic validity of 0.432, the cut-off point of 44, sensitivity of 61.2, and specificity of 62.7. The correlations of subscales with the total score were significant (r=0.654 for educational achievement, r=0.54 for job complexity, and r=0.947 for leisure activities (p<0.01)). The mean of cognitive reserve in the healthy group compared to mild cognitive impairment was higher (p<0.001) and regression analysis was significant for two variables of age and cognitive reserve (p<0.01).

The findings indicate the optimal validity and reliability of the elderly cognitive reserve scale. Due to the limitations of foreign tools and the design of the elderly cognitive reserve scale by Iranian culture, it is recommended for research in the fields of cognitive science and aging.