Abstract
INTRODUCTION: Changes in cognitive performance during shiftwork due to fatigue and circadian misalignment are well-documented. However experimental evaluations of shiftwork schedules are often limited to basic tasks such as vigilance and attention. The current study evaluated several higher order cognitive functions such as memory and task switching during four simulated shiftwork schedules. METHODS: N=27 completed a 10-day laboratory shiftwork simulation. They were randomly assigned to one of four shiftwork conditions: Condition A, 4h-on/4h-off/8h-on/8h-off schedule; Condition B, 6h-on/6h-off schedule; Conditions C and D represented to different sections of a 4h-on/4h-on call/4h-off/4h-on/4h-on call/4h-off schedule. The Automated Neuropsychological Assessment Metrics (ANAM) was used to assess cognitive function. The tasks included in this analysis were Code Substitution (CDS/CDD), Pursuit Tracking (PUR), Matching to Sample (M2S), and Switching Task (SWT). Stability of performance during waking was compared between the conditions using Kruskal-Wallis tests. RESULTS: The analysis of cognitive performance tasks yielded mixed findings. Performance on all tasks was ranked from best to worst: Condition D (>Conditions A, B, C; all p < .05), Condition A (>Conditions B, C; p < .05 and p <.001, respectively), Condition B, Condition C. Regarding stability of higher order cognitive function across the waking day, Condition A exhibited the worst stability, and was the only condition whereby performance degraded across the wake period. DISCUSSION: These findings highlight the variability in cognitive capacities during different shiftwork schedules. It is important to examine higher order cognitive function, and other cognitive abilities during shiftwork, when evaluating different shiftwork schedules.