Performance of a Multisensor Smart Ring to Evaluate Sleep: In-Lab and Home-Based Evaluation Relative to Polysomnography and Actigraphy: Importance of Generalized Versus Personalized Scoring

Study Objectives: Wearable sleep technology has rapidly expanded across the consumer market due to advances in technology and increased interest in personalized sleep assessment to improve health and performance. In this study, we tested the performance of a novel device, alongside other commercial wearables, against in-lab and at-home polysomnography (PSG). Methods: 36 healthy adults were assessed across 77 nights while wearing the Happy Ring, as well as the Actiwatch, Fitbit, Whoop, and Oura Ring devices. Subjects participated in a single night of in-lab PSG and 2 nights of at-home PSG. The Happy Ring includes sensors for skin conductance, movement, heart rate, and skin temperature. Epoch-by-epoch analyses compared the wearable de-vices to both in-lab and at-home PSG. The Happy Ring utilized two machine-learning derived scor-ing algorithms: a generalized algorithm that applied broadly to all users, and a personalized algorithm that adapted to the data of individual subjects. Results: Compared to in-lab PSG, the generalized and personalized algorithms demonstrated good sensitivity (94% and 93%, respectively) and specificity (70% and 83%, respectively). The other wearable devices also demonstrated good sensitivity (89%-94%) but lower specificity (19%-54%), relative to the Happy Ring. Accuracy was 91% for generalized and 92% for personalized algorithms, compared to other devices that ranged from 84%-88%. The generalized algorithm demonstrated an accuracy of 67%, 85%, and 85% for light, deep, and REM sleep, respectively. The personalized algorithm was 81%, 95%, and 92% accurate for light, deep, and REM sleep, re-spectively. Conclusions: The Happy Ring performed well at home and in the lab, especially regarding sleep-wake detection. The personalized algorithm demonstrated improved detection accuracy over the generalized approach and other devices, suggesting that adaptable, dynamic algorithms can enhance sleep detection accuracy.

Is sleep bruxism related to the levels of enzymes involved in the serotonin synthesis pathway?

Objectives This exploratory research aimed to evaluate the levels of tryptophan hydroxylase 1 (TPH1) and aromatic l-amino acid decarboxylase (DDC), which play an important role in the serotonin synthesis pathway, in individuals with sleep bruxism (SB) diagnosed using audio–video polysomnography (vPSG) and compare them with that of individuals not presenting with SB. Materials and methods The study included adult patients hospitalized in the Department and Clinic of Internal Medicine, Occupational Diseases, Hypertension and Clinical Oncology at the Wroclaw Medical University. The participants underwent a single-night vPSG for the evaluation of the SB parameters. Peripheral blood samples were also collected from them for estimating the serum levels of TPH1 and DDC. Results A total of 105 patients (80 women and 25 men) were included in the study. All the patients were Caucasians and aged 18–63 years (mean age: 33.43 ± 10.8 years). Seventy-five patients (71.43%) presented with SB, of which 50 (47.62%) had severe SB, while the remaining 30 patients (28.57%) did not. No statistically significant differences in TPH1 and DDC levels were observed between the individuals with SB and without SB. A significant negative correlation was found between tonic SB episodes and DDC levels (p = 0.0012). Other correlations between the SB parameters and the levels of the studied enzymes were statistically insignificant (p > 0.05 for all comparisons). Conclusions The levels of the enzymes that are crucial for serotonin synthesis (TPH1 and DDC) did not seem to influence SB. Clinical relevance This study provides important insights for further research on the relationship between the serotonin pathway and SB, which should take into account not only the process of serotonin synthesis but also the effect of serotonin-dependent neurotransmission on SB.

Quarreling After a Sleepless Night: Preliminary Evidence of the Impact of Sleep Deprivation on Interpersonal Conflict

Although poor sleep has been found to correlate with deteriorations in romantic relationships, its causal impact on interpersonal conflict has not previously been studied. Therefore, 30 couples were randomly assigned to either a single night of total sleep deprivation or a night of normal sleep to test the effects of sleep deprivation on couples’ conflict. After the experimental night, all participants discussed a topic of recurrent conflict for 15 min. We collected pre- and post-conflict measures of cortisol, self-reports of feelings, and satisfaction with the conflictual discussion. Multilevel analyses revealed higher cortisol levels during conflict and less positive affect prior to and after the conflict for sleep-deprived couples compared to couples in the control condition. These findings provide initial evidence for a causal negative impact of sleep deprivation on couples’ conflicts.

Overnight variation in tidal expiratory flow limitation in COPD patients and its correction: an observational study

Background Tidal expiratory flow limitation (EFLT) is common among COPD patients. Whether EFLT changes during sleep and can be abolished during home ventilation is not known. Methods COPD patients considered for noninvasive ventilation used a ventilator which measured within-breath reactance change at 5 Hz (∆Xrs) and adjusted EPAP settings to abolish EFLT. Participants flow limited (∆Xrs > 2.8) when supine underwent polysomnography (PSG) and were offered home ventilation for 2 weeks. The EPAP pressure that abolished EFLT was measured and compared to that during supine wakefulness. Ventilator adherence and subjective patient perceptions were obtained after home use. Results Of 26 patients with supine EFLT, 15 completed overnight PSG and 10 the home study. In single night and 2-week home studies, EFLT within and between participants was highly variable. This was unrelated to sleep stage or body position with only 14.6% of sleep time spent within 1 cmH2O of the awake screening pressure. Over 2 weeks, mean EPAP was almost half the mean maximum EPAP (11.7 vs 6.4 cmH2O respectively). Group mean ∆Xrs was ≤ 2.8 for 77.3% of their home use with a mean time to abolish new EFLT of 5.91 min. Adherence to the ventilator varied between 71 and 100% in prior NIV users and 36–100% for naïve users with most users rating therapy as comfortable. Conclusions Tidal expiratory flow limitation varies significant during sleep in COPD patients. This can be controlled by auto-titrating the amount of EPAP delivered. This approach appears to be practical and well tolerated by patients. Trial registration: The trial was retrospectively registered at CT.gov NCT04725500.

P001 Safety, tolerability, and efficacy of 1 month of atomoxetine plus oxybutynin in obstructive sleep apnoea

Introduction Single-night studies with noradrenergic and anti-muscarinics have recently been shown to improve upper-airway function and reduce obstructive sleep apnoea (OSA) severity. This study aimed to determine the safety, tolerability, and efficacy profile of longer-term use of different doses of the noradrenergic agent atomoxetine combined with the anti-muscarinic oxybutynin (ato-oxy) in people with OSA. Methods Thirty-nine people with predominantly severe OSA received either 80/5mg ato-oxy, 40/5mg ato-oxy, 40/2.5mg ato-oxy or placebo nightly for 30 days according to a double-blind, randomised, parallel design. Safety and tolerability were assessed via weekly phone calls for adverse events, vital signs and objective measures of alertness and memory. Participants completed 3 in-laboratory sleep studies (baseline, night 1 and night 30) to assess efficacy. Results Side effects were generally mild and consistent with the known side-effect profile of each drug alone (e.g. dose-dependent increases in dry mouth with oxybutynin). Heart rate increased by night 30 in two of the drug arms versus placebo (e.g. 80/5mg ~9 beats/min, p=0.01). Blood pressure and measures of alertness and memory did not change between conditions. AHI4 and hypoxic burden decreased by ~50% in the 80/5mg arm on night 1 with similar magnitude reductions at night 30. ~50% of participants indicated willingness to continue taking the medication post-study. Discussion 1 month of nightly noradrenergic and anti-muscarinic combination therapy is generally well-tolerated with a side effect profile consistent with each agent alone. These findings also further highlight the potential to target noradrenergic and anti-muscarinic mechanisms for OSA pharmacotherapy development.

P074 Night-to-night variability in obstructive sleep apnoea severity is associated with hypertension and high misdiagnosis rates

Introduction The impact of night-to-night variability in obstructive sleep apnoea (OSA) severity on important health outcomes such as blood pressure is unknown. This study aimed to determine the effects of night-to-night variability in the apnoea/hypopnoea index (AHI) on hypertension risk and OSA misdiagnoses. Methods In-home nightly monitoring of 67,278 participants from 151 countries, over ~170 nights per participant between July 2020 to March 2021 using a validated under mattress sleep analyser. Blood pressure measurements were available in 12,295 participants. OSA was defined as a mean nightly AHI >15events/h. Night-to-night variability was assessed as the standard deviation of AHI across nights. Results 22.6% (95% CI: 20.9–24.3) of the cohort (13% of women, 25% of men) had an average AHI> 15 events/h sleep. The average nightly AHI variability ranged from 3±1 in people without OSA to 14±6 in people with severe OSA. Higher mean AHI (OR [95% CI], 1.44 [1.29, 1.61]) and greater nightly variability in AHI (1.57 [1.39, 1.76]) were associated with hypertension. In people with a mean AHI of ≥5 events/h, high night-to-night AHI variability was associated with a ~30% increased risk in hypertension, independent of OSA severity category. Likelihood of misdiagnosis of OSA based on a single night compared to the mean across all nights was ~20%; this decreased with more monitoring nights. Conclusions These findings highlight the novel, important information that simple multi-night monitoring of OSA can yield. This includes the potential importance of night-to-night variation and its contribution to hypertension and increased confidence of OSA diagnoses.

Green morays (Gymnothorax funebris) have sedentary ways in mangrove bays, but also ontogenetic forays to reef enclaves

Surprisingly, little is known about basic life history of the largest moray eel species in the Caribbean region, the green moray eel (Gymnothorax funebris). Sixteen eels were captured from the mangrove fringe in multiple bays on St. Croix, USVI, implanted with coded acoustic transmitters, and their movements were tracked for up to 11 months using an array of 37 stationary acoustic receivers. They exhibited high site fidelity in the bays during their residence, using the same general parts of individual bays and did not switch bays except for one individual. There was no relationship between eel size (mean TL = 83 cm, range = 54–126 cm) and home range size (mean area of 95% KUD = 5.8 ha ± 0.7 SE). Most individuals were more frequently detected at night than during the day suggesting greater nocturnal activity. Several of the larger eels (mean TL = 93 cm ± 5.9 SE) showed clear and permanent emigration tracks out of the mangrove estuary to coral reef habitats offshore. For some individuals, these habitat shifts were preceded by exploratory movements away from the eel’s typical home range the night before emigration. All final emigration events took place nocturnally, happened during a single night, and occurred during months from December to May. Mean emigration speed was 3.4 km/h. This study is the first documentation of an ontogenetic habitat shift in moray eels, as well as the first determination of home range size for this species and their site fidelity in mangrove habitats.

No Effect of Chronotype on Sleepiness, Alertness, and Sustained Attention during a Single Night Shift

The study’s aim was to examine the effect of chronotype on cognitive performance during a single night shift. Data were collected from 72 (36f) young, healthy adults in a laboratory study. Participants had a 9 h sleep period (03:00–12:00) followed by an 8 h night shift (23:00–07:00). During the night shift, participants completed five test sessions, which included measures of subjective sleepiness, subjective alertness, and sustained attention (i.e., psychomotor vigilance task; PVT). Dim light melatonin onset (DLMO) was derived from saliva samples taken during the evening preceding the night shift. A tertile split of DLMO was used to determine three chronotype categories: earlier (DLMO = 20:22 ± 0:42), intermediate (DLMO = 21:31 ± 0:13), and later (DLMO = 22:54 ± 0:54). There were (a) significant main effects of test session (all p < 0.001); (b) no main effects of chronotype; and (c) no interaction effects between chronotype and test session on sleepiness, alertness, PVT response time, and PVT lapses. The results indicate that under controlled sleeping conditions, chronotype based on dim light melatonin onset did not affect nighttime performance. Differences in performance during night shift between chronotypes reported by field studies may be related to differences in the amount and/or timing of sleep before or between night shifts, rather than circadian timing.

Sleep Study Measures on Postoperative Night 1 Following Implantation of the Hypoglossal Nerve Stimulator

Objective To examine the changes in measures of sleep apnea severity and hypoxemia on the first postoperative night following implantation of the hypoglossal nerve stimulator. Study Design This was a single-arm prospective cohort study. Setting A single academic sleep surgical practice. Methods Subjects with moderate to severe obstructive sleep apnea underwent implantation of the hypoglossal nerve stimulator (HGNS) and were discharged to home the same day as surgery. A single-night WatchPAT study was performed on the night immediately following surgery (PON 1) and was compared to baseline sleep testing. Results Twenty subjects who were an average of 58.6 ± 2.5 years old, were 25% female, and had a mean body mass index of 28.1 ± 0.9 kg/m2 completed the study. Mean O2 nadir at baseline was 79.6% ± 1.1% compared to 82.7% ± 0.9% ( P = .013) on PON 1. One patient demonstrated a >10% worsening in O2 nadir. Only 2 additional patients demonstrated a worsening in O2 nadir on PON 1, each by only 1 percentage point. Neither mean time spent below SpO2 88% nor oxygen desaturation index (ODI) worsened postoperatively (mean time spent below oxygen saturation of 88%, 27.8 ± 7.85 vs 11.2 ± 5.2, P = .03; mean ODI, 29.6 ± 5.2/h vs 21.0 ± 5.4/h, P = .10). Mean obstructive apnea hypopnea index (AHI) was no worse (40.6 ± 4.7/h to 28.7 ± 4.2/h, P = .02), with only 2 patients experiencing an obstructive AHI >20% more severe than baseline. Only 1 patient demonstrated a clinically meaningful increase in central AHI on PON 1. Conclusions Overall, AHI and measures of nocturnal hypoxemia are stable, if not improved, on PON 1 following HGNS implantation. These findings support the safety of same-day discharge following implantation of the hypoglossal nerve stimulator.

Quantifying year-round nocturnal bird migration with a fluid dynamics model

To understand the influence of biomass flows on ecosystems, we need to characterize and quantify migrations at various spatial and temporal scales. Representing the movements of migrating birds as a fluid, we applied a flow model to bird density and velocity maps retrieved from the European weather radar network, covering almost a year. We quantified how many birds take-off, fly, and land across Western Europe to (1) track bird migration waves between nights, (2) cumulate the number of birds on the ground and (3) quantify the seasonal flow into and out of the study area through several regional transects. Our results identified several migration waves that crossed the study area in 4 days only and included up to 188 million (M) birds that took-off in a single night. In spring, we estimated that 494 M birds entered the study area, 251 M left it, and 243 M birds remained within the study area. In autumn, 314 M birds entered the study area while 858 M left it. In addition to identifying fundamental quantities, our study highlights the potential of combining interdisciplinary data and methods to elucidate the dynamics of avian migration from nightly to yearly time scales and from regional to continental spatial scales.