Cognitive control, bedtime patterns, and testing time in female adolescent students: behavioral and neuro-electrophysiological correlates

Abstract

Introduction: Shorter and/or disrupted sleep during adolescence is associated with cognitive and mental health risks, particularly in females. We explored the relationship between bedtime behavior patterns co-varying with Social Jet Lag (SJL) and School Start Times (SST) and neurocognitive performance in adolescent female students.

Methods: To investigate whether time of day (morning vs. afternoon), early SSTs and days of the school week can be correlated with neurocognitive correlates of sleep insufficiency, we recruited 24 female students aged 16-18 to report sleep logs, and undergo event-related electroencephalographic recordings on Monday, Wednesday, mornings, and afternoons. Using a Stroop task paradigm, we analyzed correlations between reaction times (RTs), accuracy, time of day, day of week, electroencephalographic data, and sleep log data to understand what relationships may exist.

Results: Participants reported a 2-h sleep phase delay and SJL. Stroop interference influenced accuracy on Monday and Wednesday similarly, with better performance in the afternoon. For RTs, the afternoon advantage was much larger on Monday than Wednesday. Midline Event-Related Potentials (ERPs) yielded higher amplitudes and shorter latencies on Wednesday morning and Monday afternoon, in time windows related to attention or response execution. A notable exception were delayed ERP latencies on Wednesday afternoon. The latter could be explained by the fact that delta EEG waves tended to be the most prominent, suggesting heightened error monitoring due to accumulating mental fatigue.

Discussion: These findings provide insights into the interaction between SJL and SST and suggest evidence-based criteria for planning when female adolescents should engage in cognitive-heavy school activities such as tests or exams.

Keywords: adolescent sleep; bed time behaviors; circadian rhythm; electroencephalography; school start time; sleep patterns; social jet lag.

Figure 1

Midsleep and wakeup times for each weekday. Mean midsleep for workday and free day are shown with gray and black dashed lines, respectively. SJL shown calculated to be 123 min. Error bars are SEM. Time of the day is expressed as hundreds of hours over 48-h period, key local times are shown for ease of interpretation; notice that minor ticks correspond to ½ hour (30 min).

Figure 2

Mean and 99% confidence intervals for sleep logs for each day of the week. The gray box above panel A denotes the 99% confidence interval of the recommended amount of sleep for adolescents [see American Academy of Pediatrics (81)].

Figure 3

Average Daily Social Jet Lag, Average Social Jet Lag corrected for sleep deprivation, and average daily sleep deprivation related to school start time. All expressed in minutes.

Figure 4

Left Panel: Reaction time Interference for correctly answered trials, for each Stroop trial type on Monday and Wednesday (AM and PM) testing. Right Panel: Accuracy interference in percent correct, for each Stroop trial type., on Monday and Wednesday (AM and PM) testing. Bars indicate standard errors.

Figure 5

ERP trace for the (A) Fz, (B) Cz, and (C) Pz electrodes on Monday and Wednesday, in both the morning (solid line) and afternoon (dashed line) testing times.

Figure 6

Mean absolute value of Stroop event-related EEG power for delta, theta, alpha and beta band frequencies on Monday morning, Monday afternoon, Wednesday morning, and Wednesday afternoon.