Effect of sleep quality on different aspects of executive function in older Iranians

OBJECTIVE: Sleep is one of the most important needs for humans and is negatively affected by age. Executive functioning is a key element of cognition that also faces attrition with ageing. Therefore, this study aimed to determine the relationship between sleep quality and different aspects of executive function in older adults using specialised tests for deep assessment. METHODS: This descriptive study sampled 100 older individuals aged 60 years or older enrolled in an adult day care centre. Self-reported sleep status was collected using the Pittsburgh Sleep Quality Index (PSQI). Aspects of executive functioning were recorded using the Tower of London test (TOL), the Wisconsin Card Sorting Test (WCST) and the Trail Making Test (TMT). Performance on these tests was compared by sleep status using hierarchical regression. RESULTS: Sleep status was independently associated with poorer executive functioning, indicated by perseverative errors, categories and incorrect replacement on the Wisconsin Card Sorting Test, as well as the Trail Making Test B. Additionally there was no significant interaction between the Tower of London Test score and sleep status. CONCLUSIONS: This study indicates a significant association between sleep status and some aspects of executive function. These findings highlight the importance of sleep quality on cognitive performance in older adults.