How does obstructive sleep apnea alter cerebral hemodynamics?Gregori-Pla, Clara; Zirak, Peyman; Cotta, Gianluca; Bramon, Pau; Blanco, Igor; Serra, Isabel; Mola, Anna; Fortuna, Ana; Solà-Soler, Jordi; Giraldo Giraldo, Beatriz F; Durduran, Turgut; Mayos, Mercedes
doi: 10.1093/sleep/zsad122pmid: 37336476
Study ObjectivesWe aimed to characterize the cerebral hemodynamic response to obstructive sleep apnea/hypopnea events, and evaluate their association to polysomnographic parameters. The characterization of the cerebral hemodynamics in obstructive sleep apnea (OSA) may add complementary information to further the understanding of the severity of the syndrome beyond the conventional polysomnography.MethodsSevere OSA patients were studied during night sleep while monitored by polysomnography. Transcranial, bed-side diffuse correlation spectroscopy (DCS) and frequency‐domain near-infrared diffuse correlation spectroscopy (NIRS-DOS) were used to follow microvascular cerebral hemodynamics in the frontal lobes of the cerebral cortex. Changes in cerebral blood flow (CBF), total hemoglobin concentration (THC), and cerebral blood oxygen saturation (StO2) were analyzed.ResultsWe considered 3283 obstructive apnea/hypopnea events from sixteen OSA patients (Age (median, interquartile range) 57 (52‐64.5); females 25%; AHI (apnea‐hypopnea index) 84.4 (76.1‐93.7)). A biphasic response (maximum/minimum followed by a minimum/maximum) was observed for each cerebral hemodynamic variable (CBF, THC, StO2), heart rate and peripheral arterial oxygen saturation (SpO2). Changes of the StO2 followed the dynamics of the SpO2, and were out of phase from the THC and CBF. Longer events were associated with larger CBF changes, faster responses and slower recoveries. Moreover, the extrema of the response to obstructive hypopneas were lower compared to apneas (p < .001).ConclusionsObstructive apneas/hypopneas cause profound, periodic changes in cerebral hemodynamics, including periods of hyper- and hypo-perfusion and intermittent cerebral hypoxia. The duration of the events is a strong determinant of the cerebral hemodynamic response, which is more pronounced in apnea than hypopnea events.
A daily examination of executive functioning and chronotype in bedtime procrastinationCarlson, Steven E; Suchy, Yana; Baron, Kelly Glazer; Johnson, Kimberley T; Williams, Paula G
doi: 10.1093/sleep/zsad145pmid: 37225142
Study ObjectivesBedtime procrastination, or delays in bedtime not attributable to external obligations, is a behavioral tendency that undermines sleep and is conceptualized as a consequence of poor self-regulation. Prior studies investigating the mechanistic role of self-regulation in bedtime procrastination relied on cross-sectional methods and self-reported self-regulation. The present study examined the association between bedtime procrastination and both objective and self-reported executive functioning (EF) as indices of self-regulation, as well as the moderating role of chronotype, using methods that examined these associations at the daily level.MethodsA total of 273 young adult participants (78% female; Mage = 24.4) completed daily measures of objective EF (i.e., Stroop task), self-reported EF (i.e., self-reported cognitive, behavioral, and emotional regulation difficulties), and bedtime procrastination over 14 days, in addition to measures of chronotype. Multilevel models were constructed to examine the associations between bedtime procrastination and EF, as well as EF-chronotype interactions.ResultsPoorer daily objective EF and self-reported behavioral regulation were associated with greater same-night bedtime procrastination. Additionally, poorer subjective cognitive and emotional regulation were associated with greater average bedtime procrastination across 14 days. Later chronotypes reported greater bedtime procrastination than early chronotypes.ConclusionsThe present study provides support for the association between EF and bedtime procrastination, but finds no evidence for the moderating role of chronotype in this association. Results suggest that some EF processes may be more relevant to bedtime procrastination than others. Current findings have implications for assessment and intervention for this consequential sleep-relevant behavioral tendency.
Supplementation of ambient lighting with a task lamp improves daytime alertness and cognitive performance in sleep-restricted individualsGrant, Leilah K; Crosthwaite, Phoebe C; Mayer, Matthew D; Wang, Wei; Stickgold, Robert; St. Hilaire, Melissa A; Lockley, Steven W; Rahman, Shadab A
doi: 10.1093/sleep/zsad096pmid: 37026184
Study ObjectivesWe examined the impact of adding a single-high-melanopic-illuminance task lamp in an otherwise low-melanopic-illuminance environment on alertness, neurobehavioral performance, learning, and mood during an 8-h simulated workday.MethodsSixteen healthy young adults [mean(±SD) age = 24.2 ± 2.9, 8F] participated in a 3-day inpatient study with two 8-h simulated workdays and were randomized to either ambient fluorescent room light (~30 melanopic EDI lux, 50 lux), or room light supplemented with a light emitting diode task lamp (~250 melanopic EDI lux, 210 lux) in a cross-over design. Alertness, mood, and cognitive performance were assessed throughout the light exposure and compared between conditions using linear mixed models.ResultsThe primary outcome measure of percentage correct responses on the addition task was significantly improved relative to baseline in the supplemented condition (3.15% ± 1.18%), compared to the ambient conditions (0.93% ± 1.1%; FDR-adj q = 0.005). Additionally, reaction time and attentional failures on the psychomotor vigilance tasks were significantly improved with exposure to supplemented compared to ambient lighting (all, FDR-adj q ≤ 0.030). Furthermore, subjective measures of sleepiness, alertness, happiness, health, mood, and motivation were also significantly better in the supplemented, compared to ambient conditions (all, FDR-adj q ≤ 0.036). There was no difference in mood disturbance, affect, declarative memory, or motor learning between the conditions (all, FDR-adj q ≥ 0.308).ConclusionsOur results show that supplementing ambient lighting with a high-melanopic-illuminance task lamp can improve daytime alertness and cognition. Therefore, high-melanopic-illuminance task lighting may be effective when incorporated into existing suboptimal lighting environments.Clinical trialsNCT04745312. Effect of Lighting Supplementation on Daytime Cognition. https://clinicaltrials.gov/ct2/show/NCT04745312
Sleep and mental health in recruit paramedics: a 6-month longitudinal studyNguyen, Elle; Meadley, Ben; Harris, Rachael; Rajaratnam, Shantha M W; Williams, Brett; Smith, Karen; Bowles, Kelly-Ann; Dobbie, Megan L; Drummond, Sean P A; Wolkow, Alexander P
doi: 10.1093/sleep/zsad050pmid: 36861384
Study ObjectivesTo explore potential relationships and longitudinal changes in sleep and mental health in recruit paramedics over the first 6 months of work, and whether sleep disturbances pre-emergency work predict future mental health outcomes.MethodsParticipants (N = 101, 52% female, Mage = 26 years) completed questionnaires prior to (baseline), and after 6 months of emergency work to assess for symptoms of insomnia, obstructive sleep apnea, post-traumatic stress disorder (PTSD), depression, anxiety, and trauma exposure. At each timepoint, participants also completed a sleep diary and wore an actigraph for 14 days to assess sleep patterns. Correlations between baseline sleep and mental health were conducted and changes in these variables across timepoints were examined using linear mixed models. Hierarchical regressions assessed whether sleep at baseline predicted mental health at follow-up.ResultsInsomnia and depression symptoms, and total sleep time increased while sleep onset latency decreased across the first 6 months of emergency work. Participants experienced an average of 1 potentially traumatic event during the 6-month period. Baseline insomnia predicted increased depression symptoms at the 6-month follow-up, while baseline wake after sleep onset predicted follow-up PTSD symptoms.ConclusionResults highlight an increase in insomnia and depression across the initial months of emergency work, while sleep disturbances before emergency work were identified as potential risk factors for the development of depression and PTSD among paramedics in their early career. Screening and early interventions targeting poor sleep at the beginning of emergency employment may assist in reducing the risk of future mental health outcomes in this high-risk occupation.