Obstructive Sleep Apnea, Platelet Aggregation, and Cardiovascular Risk.

Background: Although related, the precise mechanisms linking obstructive sleep apnea (OSA) and cardiovascular disease (CVD) are unclear. Platelets are mediators of CVD risk and thrombosis and prior studies suggested associations of OSA and platelet activity. The aim of this study is to assess the link between OSA, platelet activity, and CVD-related risk factors.

The stability of slow-wave sleep and EEG oscillations across two consecutive nights of laboratory polysomnography in cognitively normal older adults.

Laboratory polysomnography provides gold-standard measures of sleep physiology, but multi-night investigations are resource intensive. We assessed the night-to-night stability via reproducibility metrics for sleep macrostructure and electroencephalography oscillations in a group of cognitively normal adults attending two consecutive polysomnographies. Electroencephalographies were analysed using an automatic algorithm for detection of slow-wave activity, spindle and K-complex densities.

Nasal resistance and inflammation: mechanisms for obstructive sleep apnea from chronic rhinosinusitis.

Study Objectives: We have previously estimated that the prevalence of obstructive sleep apnea (OSA) among World Trade Center rescue and recovery workers is 75% and identified that having symptoms of chronic rhinosinusitis (CRS) is an independent risk factor for OSA in this population. Nasal inflammation and/or elevated awake nasal resistance that carried over into sleep could explain this association. To understand the mechanism(s) for the elevated risk of OSA observed in World Trade Center responders with CRS symptoms we examined if elevated awake supine nasal resistance was associated with OSA, CRS and/or nasal inflammatory biomarkers.

Lack of association of impaired upper airway sensation with the presence or absence of obstructive sleep apnoea or chronic rhinosinusitis in World Trade Center responders.

Objective: Examine sensory function of the upper airway in four groups of subjects recruited from the World Trade Centre General Responder Cohort (WTCGRC), with/without obstructive sleep apnoea (OSA), and with/without chronic rhinosinusitis (CRS).

Methods: Upper airway sensory function was determined using 2-point discrimination (2-PD) and vibration threshold (VT) in 163 WTCGRC subjects with both OSA and CRS (cases), OSA or CRS alone and without OSA or CRS (controls). Presence of OSA was determined from clinical sleep studies or home sleep testing.

Sleep-wake body temperature regulates tau secretion in mice and correlates with CSF and plasma tau in humans.

The sleep-wake cycle regulates interstitial fluid and cerebrospinal fluid (CSF) tau levels in both mouse and human by mechanisms that remain unestablished. Here, we reveal a novel pathway by which wakefulness increases extracellular tau levels in mouse and humans. In mice, higher body temperature (BT) associated with wakefulness and sleep deprivation increased CSF tau.

Ventilatory Burden as a Measure of Obstructive Sleep Apnea Severity Is Predictive of Cardiovascular and All-Cause Mortality.

The apnea-hypopnea index (AHI), used for the diagnosis of obstructive sleep apnea, captures only the frequency of respiratory events and has demonstrable limitations. We propose a novel automated measure, termed "ventilatory burden" (VB), that represents the proportion of overnight breaths with less than 50% normalized amplitude, and we show its ability to overcome limitations of AHI. Data from two epidemiological cohorts (EPISONO [Sao Paolo Epidemiological Study] and SHHS [Sleep Heart Health Study]) and two retrospective clinical cohorts (DAYFUN; New York University Center for Brain Health) were used in this study to ) derive the normative range of VB, ) assess the relationship between degree of upper airway obstruction and VB, and ) assess the relationship between VB and all-cause and cardiovascular disease (CVD) mortality with and without hypoxic burden that was derived using an in-house automated algorithm.

Night-to-night reliability and agreement of obstructive sleep apnea pathophysiologic mechanisms estimated with phenotyping using polysomnography in cognitively normal elderly participants.

Study Objectives: Phenotyping using polysomnography (PUP) is an algorithmic method to quantify physiologic mechanisms underlying obstructive sleep apnea (OSA): loop gain (LG1), arousal threshold (ArTH), and upper airway collapsibility (Vpassive) and muscular compensation (Vcomp). The consecutive-night test-retest reliability and agreement of PUP-derived estimates are unknown. From a cohort of elderly (age ≥55 years), largely non-sleepy, community-dwelling volunteers who underwent in-lab polysomnography (PSG) on 2 consecutive nights, we determined the test-retest reliability and agreement of PUP-estimated physiologic factors.

International Consensus Statement on Obstructive Sleep Apnea.

Background: Evaluation and interpretation of the literature on obstructive sleep apnea (OSA) allows for consolidation and determination of the key factors important for clinical management of the adult OSA patient. Toward this goal, an international collaborative of multidisciplinary experts in sleep apnea evaluation and treatment have produced the International Consensus statement on Obstructive Sleep Apnea (ICS:OSA).

Methods: Using previously defined methodology, focal topics in OSA were assigned as literature review (LR), evidence-based review (EBR), or evidence-based review with recommendations (EBR-R) formats.

The Link between Obstructive Sleep Apnea and Neurocognitive Impairment: An Official American Thoracic Society Workshop Report.

There is emerging evidence that obstructive sleep apnea (OSA) is a risk factor for preclinical Alzheimer's disease (AD). An American Thoracic Society workshop was convened that included clinicians, basic scientists, and epidemiologists with expertise in OSA, cognition, and dementia, with the overall objectives of summarizing the state of knowledge in the field, identifying important research gaps, and identifying potential directions for future research. Although currently available cognitive screening tests may allow for identification of cognitive impairment in patients with OSA, they should be interpreted with caution.

Association between lower body temperature and increased tau pathology in cognitively normal older adults.

Background: Preclinical studies suggest body temperature (Tb) and consequently brain temperature has the potential to bidirectionally interact with tau pathology in Alzheimer's Disease (AD). Tau phosphorylation is substantially increased by a small (<1 °C) decrease in temperature within the human physiological range, and thermoregulatory nuclei are affected by tau pathology early in the AD continuum. In this study we evaluated whether Tb (as a proxy for brain temperature) is cross-sectionally associated with clinically utilized markers of tau pathology in cognitively normal older adults.

Characterizing sleep-wake patterns in mothers and children in an agrarian community: results from the Ghana Randomized Air Pollution and Health Study.

Study Objectives: Several studies have examined sleep patterns in rural/indigenous communities, however little is known about sleep characteristics in women of reproductive age, and children within these populations. We investigate sleep-wake patterns in mothers and children (ages 3-5 years) leveraging data from the Ghana Randomized Air Pollution and Health Study (GRAPHS).

Methods: The GRAPHS cohort comprises of rural/agrarian communities in Ghana and collected multiday actigraphy in a subset of women and children to assess objective sleep-wake patterns.

Interactive Associations of Neuropsychiatry Inventory-Questionnaire Assessed Sleep Disturbance and Vascular Risk on Alzheimer's Disease Stage Progression in Clinically Normal Older Adults.

To determine whether sleep disturbance (SD) and vascular-risk interact to promote Alzheimer's disease (AD) stage-progression in normal, community-dwelling older adults and evaluate their combined risk beyond that of established AD biomarkers. Longitudinal data from the National Alzheimer's Coordinating Center Uniform-Dataset. SD data (i.

Selective Continuous Positive Airway Pressure Withdrawal With Supplemental Oxygen During Slow-Wave Sleep as a Method of Dissociating Sleep Fragmentation and Intermittent Hypoxemia-Related Sleep Disruption in Obstructive Sleep Apnea.

Obstructive sleep apnea (OSA) is considered to impair memory processing and increase the expression of amyloid-β (Aβ) and risk for Alzheimer's disease (AD). Given the evidence that slow-wave sleep (SWS) is important in both memory and Aβ metabolism, a better understanding of the mechanisms by which OSA impacts memory and risk for AD can stem from evaluating the role of disruption of SWS specifically and, when such disruption occurs through OSA, from evaluating the individual contributions of sleep fragmentation (SF) and intermittent hypoxemia (IH). In this study, we used continuous positive airway pressure (CPAP) withdrawal to recapitulate SWS-specific OSA during polysomnography (PSG), creating conditions of both SF and IH in SWS only.

Sleep duration and vascular inflammation using hybrid positron emission tomography/magnetic resonance imaging: results from the Multi-Ethnic Study of Atherosclerosis.

Study Objectives: Short sleep duration (SD) is associated with cardiovascular disease. We investigated the relationship between objective SD and subclinical atherosclerosis employing hybrid positron emission tomography/magnetic resonance imaging with F-FDG tracer in the MESA cohort.

Methods: We utilized data from Multi-Ethnic Study of Atherosclerosis-SLEEP and Multi-Ethnic Study of Atherosclerosis-PET ancillary studies.

Quantification of airway conductance from noninvasive ventilatory drive in patients with sleep apnea.

Upper airway conductance, the ratio of inspiratory airflow to inspiratory effort, quantifies the degree of airway obstruction in hypopneas observed in sleep apnea. We evaluated the ratio of ventilation to noninvasive ventilatory drive as a surrogate of conductance. Furthermore, we developed and tested a refinement of noninvasive drive to incorporate the interactions of inspiratory flow, pressure, and drive to better estimate conductance.

Endotyping Sleep Apnea One Breath at a Time: An Automated Approach for Separating Obstructive from Central Sleep-disordered Breathing.

Determining whether an individual has obstructive or central sleep apnea is fundamental to selecting the appropriate treatment. Here we derive an automated breath-by-breath probability of obstruction, as a surrogate of gold-standard upper airway resistance, using hallmarks of upper airway obstruction visible on clinical sleep studies. From five nocturnal polysomnography signals (airflow, thoracic and abdominal effort, oxygen saturation, and snore), nine features were extracted and weighted to derive the breath-by-breath probability of obstruction (P).