Five Digit Test in neuropsychological assessment of working memory in aged individuals:normative data.

Abstract

Five Digit Test (FDT) is an executive function assessment tool designed to be used across the lifespan, from children to the aged.

Objective: To provide validity evidence for FDT in the neuropsychological assessment of working memory in the aged.

Methods: A total of 100 subjects, aged between 56 and 86 years, representing both genders with varying levels of education, underwent a comprehensive clinical history and neuropsychological evaluation using FDT. The mean age of participants was 71.04 years, with 67.3% having intermediate education. Participants were categorized into two groups: Control Group and Cognitive Decline Group. To establish validity evidence, FDT scores (both time and errors) were correlated with the WAIS-III Digits scale. Spearman's correlation coefficient and ROC curve methodology were employed to determine psychometric properties.

Results: A significant and moderate negative correlation was evident between FDT Shifting (number of errors) and Digits score (rho=-0.51; p<0.0001), Direct Order (rho=-0.39; p<0.0001), and Indirect Order (rho=-0.46; p<0.0001). The area under the curve was higher for FDT Shifting (errors) (AUC=0.935) for a cutoff point greater than or equal to 5 points, compared to Digits (AUC=0.748).

Conclusion: The assessment of the number of errors in FDT Shifting appears to be a statistically significant tool for evaluating working memory impairment in the aged.