Night shift and shift work does not affect automatic cognition as reflected by duration mismatch negativity

Nurses working night shifts often face some health issues and cognitive decline. This study aimed to determine whether night shifts affected sleepiness, fatigue, and automatic auditory cognition during holidays and following night shifts. Subjective sleepiness was measured using the Stanford Sleepiness Scale, objective sleepiness and fatigue were measured using the Psychomotor Vigilance Test, and automatic auditory cognition was measured using duration mismatch negativity. All measurements were conducted twice: during holidays and following night shifts. Statistical analyses were performed using the Shapiro-Wilk, Wilcoxon signed-rank, and Kruskal-Wallis tests. In all participants, the mean Stanford Sleepiness Scale score and Psychomotor Vigilance Test reaction time following the night shift were significantly higher than those during holidays. However, the peak latency and amplitude of duration mismatch negativity did not significantly differ between during holidays and following night shifts. Similar results were obtained for most age groups (except for the 20s group). In summary, sleepiness and fatigue significantly increased following night shifts compared with during holidays, but these changes did not affect automatic auditory cognition. Age had no significant impact on sleepiness, fatigue, or automatic auditory cognition.