Biology subjects

Biller, A. M.

Publications and source records attributed to Biller, A. M..

3 recordsLinked to original sources

bioRxiv2021

Are flexible school start times associated with higher academic grades? A 4-year longitudinal study.

The mismatch between teenagers late sleep phase and early school start time results in acute and chronic sleep reductions. This is not only harmful for students learning in the short-term but may impact on students career prospects and widen social inequalities. Delaying school start times has been shown to improve sleep but whether this translates to better achievement is unresolved. The current evidence is limited due to a plethora of outcome measures and the many factors influencing sleep and grade/score trajectories. Here, we studied whether 0.5-1.5 years of exposure to a flexible school start system, with the daily choice of an 8AM or 8:50AM-start (intervention), allowed secondary school students (n=63-157, 14-19 years) to improve their quarterly school grades in a 4-year longitudinal pre-post design. We investigated whether sleep, changes in sleep or frequency of later starts predicted grade improvements in the flexible system. Our mixed model regressions with 5,111-16,724 official grades as outcomes did not indicate meaningful grade improvements in the flexible system per se or with previously observed sleep variables (nor their changes) - the covariates academic quarter, discipline and grade level had a greater, more systematic effect in our sample. Importantly, this finding does not preclude improvements in learning and cognition in our sample. However, at the dose received here, intermittent sleep benefits did not obviously translate into detectable grade changes, which is in line with several other studies and highlights that grades are suboptimal to evaluate timetabling interventions despite their importance for future success. Significance statementEarly school start times worldwide clash with teenagers delayed sleep-wake rhythms. This mismatch results in sleep restrictions below healthy amounts, which compromises health and performance and further aggravates social disparities. Since adequate sleep is important for learning and concentration, there is the strong expectation that counteracting sleep deprivation with delayed school starts results in better academic achievement. We add important high-resolution, longitudinal data to this unresolved scientific debate. When controlling for confounders, our results do not support that improved sleep leads to grade changes within 1.5 years in a flexible start system. While grades are suboptimal to measure later school start effects on performance, they nevertheless open doors to higher education worldwide and thus determine future trajectories.

scientific communication and education↗

bioRxiv2021

One year later: longitudinal effects of flexible school start times on teenage sleep and subjective psychological outcomes

Early school times fundamentally clash with the late sleep of teenagers. This mismatch results in chronic sleep deprivation, which poses acute and long-term health risks and impairs students learning. Despite conclusive evidence that delaying school times has immediate benefits for sleep, the long-term effects on sleep are unresolved due to a shortage of longitudinal data. Here, we studied whether a flexible school start system, with the daily choice of an 8AM or 08:50AM-start, allowed secondary school students to improve their sleep and psychological functioning in a longitudinal pre-post design over exactly 1 year. Based on 2 waves, each with 6-9 weeks of daily sleep diary, we found that students maintained their 1-hour-sleep gain on days with later starts, both longitudinally (n=28) and cross-sectionally (n=79). This sleep gain was independent of chronotype and frequency of later starts but differed between genders. Girls were more successful in keeping early sleep onsets despite later sleep offsets, whereas boys delayed their onsets and thus had reduced sleep gains after 1 year. Students also reported psychological benefits (n=93), increased sleep quality and reduced alarm-driven waking on later school days. Despite these benefits on later schooldays, overall sleep duration was not extended in the flexible system. This was likely due to the persistently low uptake of the late-start option. If uptake can be further promoted, the flexible system is an appealing alternative to a fixed delay of school starts owing to possible circadian advantages (speculatively through prevention of phase-delays) and psychological mechanisms (e.g. sense of control). Significance statementTeenage sleep becomes progressively later during adolescence but school starts do not accommodate this shifted sleep window. This mismatch results in chronic sleep deprivation in teenagers worldwide, which is a pervasive public health concern. Delaying school starts could counteract this misalignment if students keep sleep onsets stable. However, few studies have investigated long-term effects of delayed starts on sleep. We observed here that students slept persistently longer and better when school started later in a flexible start system. Girls were especially successful in keeping stable onsets. Students also benefitted psychologically and liked the flexible system despite only a modest uptake of later starts. The flexible system is an interesting alternative to a fixed delay and should receive more scientific attention.

neuroscience↗

bioRxiv2021

Validation of the Munich Actimetry Sleep Detection Algorithm for estimating sleep-wake patterns from activity recordings

Periods of sleep and wakefulness can be estimated from wrist-locomotor activity recordings via algorithms that identify periods of relative activity and inactivity. Here, we evaluated the performance of our Munich Actimetry Sleep Detection Algorithm (MASDA). MASDA uses a moving 24-hour-threshold and correlation procedure estimating relatively consolidated periods of sleep and wake. MASDA was validated against sleep logs and polysomnography. Sleep-log validation was performed on 2 field samples collected over 54 and 34 days (median) in 34 adolescents and 28 young adults. Polysomnographic validation was performed on a clinical sample of 23 individuals undergoing 1 night of polysomnography. Epoch-by-epoch analyses were conducted and comparisons of sleep measures via Bland-Altman plots and correlations. Compared with sleep logs, MASDA classified sleep with a median sensitivity of 80% (IQR = 75-86%) and specificity of 91% (87-92%). Mean onset and offset times were highly correlated (r = 0.86-0.91). Compared with polysomnography, MASDA reached a median sensitivity of 92% (85-100%), but low specificity of 33% (10-98%), owing to the low frequency of wake episodes in the nighttime polysomnographic recordings. MASDA overestimated sleep onset (~21 min) and underestimated wake after sleep onset (~26 min), while not performing systematically different from polysomnography in other sleep parameters. These results demonstrate the validity of MASDA to faithfully estimate sleep-wake patterns in field studies. With its good performance across day- and nighttime, it enables analyses of sleep-wake patterns in long recordings performed to assess circadian and sleep regularity and is therefore an excellent objective alternative to sleep logs in field settings.

neuroscience↗