Danny Eckert

Flinders University · College of Medicine and Public Health

Most approaches to advance simplified physiology-based precision medicine strategies for obstructive sleep apnea (OSA) focus on sleep parameters (i.e., OSA endotypes). However, wakefulness physiology measures can also provide prediction insight for certain OSA therapies yet their relationship with sleep parameters has not been extensively investiga...

Consumer sleep trackers provide useful insight into sleep. However, large scale performance evaluation studies are needed to properly understand sleep tracker accuracy. This study evaluated performance of an under-mattress sensor to estimate sleep and wake versus polysomnography in a large sample, including individuals with and without sleep disord...

Circadian disruption contributes to adverse effects on sleep, performance, and health. One accepted method to track continuous daily changes in circadian timing is to measure core body temperature (CBT), and establish daily, circadian-related CBT minimum time (Tmin). This method typically applies cosine-model fits to measured CBT data, which may no...

Study Objectives Shiftwork is associated with cognitive impairment and reduced sleep time and quality, largely due to circadian misalignment. This study tested if circadian-informed lighting could improve cognitive performance and sleep during simulated night shifts versus dim control lighting. Methods Nineteen healthy participants (mean ± SD 29 ±...

Study Objective Night work has detrimental impacts on sleep and performance, primarily due to misalignment between sleep–wake schedules and underlying circadian rhythms. This study tested whether circadian-informed lighting accelerated circadian phase delay, and thus adjustment to night work, compared to blue-depleted standard lighting under simula...

Introduction Quetiapine is commonly prescribed "off-label" to people with insomnia symptoms. People with undiagnosed obstructive sleep apnea (OSA) frequently report insomnia symptoms, particularly difficulties in maintaining sleep. In 2020, 10.6 million prescriptions were dispensed for quetiapine in the United States. Yet, there is limited informat...

There are no known estimates of the prevalence, severity and impacts from breathlessness in low- and middle-income countries. This study aimed to explore the prevalence, severity, self-attributed underlying conditions and impacts of breathlessness limiting exertion in community-dwelling adults in India. This exploratory, population-based online sur...

Introduction Upper airway surgery reduces obstructive sleep apnea (OSA) severity. However, therapeutic efficacy varies between patients and inter-individual effects on upper airway physiology post-surgery are not well characterized. Nasal surgery alone may help facilitate breathing and CPAP delivery but would not be expected to yield major reductio...

Rationale: Regular, low-dose, sustained-release morphine is frequently prescribed for persistent breathlessness in chronic obstructive pulmonary disease (COPD). However, effects on daytime sleepiness, perceived sleep quality and daytime function have not been rigorously investigated. Objectives: Determine the effects of regular, low-dose, sustai...

Introduction Obstructive sleep apnoea (OSA) and obesity commonly coexist. Weight loss and exercise are recommended management options for OSA. However, most of the current evidence on diet and OSA is focused on calorie restriction rather than diet quality. The aim of the present study was to determine the association of plant-based dietary indices...

Snoring may be a risk factor for cardiovascular disease independent of other co-morbidities. However, most prior studies have relied on subjective, self-report, snoring evaluation. This study assessed snoring prevalence objectively over multiple months using in-home monitoring technology, and its association with hypertension prevalence. In this st...

Assessment of quality of life (QoL) in people living with sleep disorders using questionnaires is necessary to compare intervention benefits. Knowledge of the content and concepts covered by specific QoL instruments is essential to determine which instruments are best suited for conducting economic evaluations of sleep-related interventions. This r...

Preclinical and human physiological studies indicate that topical, selective TASK 1/3 K ⁺ channel antagonism increases upper airway dilator muscle activity and reduces pharyngeal collapsibility during anaesthesia and nasal breathing during sleep. The primary aim of this study was to determine the effects of BAY2586116 nasal spray on OSA severity an...

Obstructive sleep apnea (OSA) is a complex disease characterized by frequent complete (apnea) or partial (hypopnea) upper airway obstructed breathing. Whilst anatomical factors clearly play an important role in all patients, the degree to which anatomical versus non-anatomical causes contribute to OSA on an individual patient basis is highly variab...

Introduction: Clinical presentation of both insomnia and obstructive sleep apnea (COMISA) is common. Approximately 30% of clinical cohorts with OSA have insomnia symptoms and vice versa. The underlying pathophysiology of COMISA is multifactorial. This poses a complex clinical challenge. Currently, there are no clinical guidelines or recommendation...

Inspiratory tongue dilatory movement is believed to be mediated via changes in neural drive to genioglossus. However, this has not been studied during quiet breathing in humans. Therefore, this study investigated this relationship and its potential role in obstructive sleep apnoea (OSA). During awake supine quiet nasal breathing, inspiratory tongue...

Introduction Evidence-based guidelines recommend that adults should sleep 7-9hrs per/night. This study used multi-night, in-home, objective sleep duration monitoring to determine how often a large global community sample meets the recommended sleep duration range. Methods Data were analysed from registered users of the Withings Sleep Analyzer unde...

Background We evaluated 1) the independent and combined influence of obstructive sleep apnea (OSA) risk and a healthy lifestyle on typical OSA outcomes [excessive daytime sleepiness (EDS), depression, cardiovascular disease (CVD), and stroke]; and 2) the impact of a healthy lifestyle on survival in individuals presenting a heightened risk of OSA....

Introduction Breathing effort is an important component of obstructed breathing and determinant of arousal in obstructive sleep apnoea (OSA). However, relative effects of hypopnoea versus apnoea on effort and work of breathing (WOB) are largely unknown. This study applied a novel modelling approach to quantify breathing effort, WOB and obstruction...

Introduction Consumer sleep trackers are useful for tracking daily sleep, particularly in shift-workers, yet large, multi-night validations against direct sleep measures are lacking. Conducted as one of the largest sleep tracker validation studies to date, this study evaluated performance of an under-mattress sensor (Withings Sleep Analyzer [WSA])...

Introduction This study aimed to explore the relationship between breathlessness (severity and chronicity) and poor sleep quality. Methods Analysis of an Australia-wide, online cross-sectional survey carried out between 12 July - 2 August 2021. Community-dwelling adults were recruited from a web-based survey panel, with recruitment based on age, g...

The effects of partial sleep restriction and minimal sleep impediment on endurance exercise performance remain incompletely understood. Moreover, the suggested role of psychological factors in the relationship, or lack thereof, between sleep and endurance performance is yet to be rigorously investigated in naturalistic settings. This study investig...

We assessed: (1) the independent and joint association of obstructive sleep apnea risk and healthy lifestyle with common consequences (excessive daytime sleepiness, depression, cardiovascular disease and stroke) of obstructive sleep apnea; and (2) the effect of healthy lifestyle on survival in people with increased obstructive sleep apnea risk. Dat...

Quetiapine is an antipsychotic medication indicated for schizophrenia and bipolar disorder. However, quetiapine also has hypnotic properties and as such is increasingly being prescribed at low doses ‘off‐label’ in people with insomnia symptoms. Pharmacologically, in addition to its dopaminergic properties, quetiapine also modulates multiple other t...

CO2 inhalation has been previously reported as a treatment for central sleep apnea both when associated with heart failure or where the cause is unknown. Here we evaluated a novel CO2 supply system using a novel open mask capable of comfortably delivering a constantly inspired fraction of CO2 (FiCO2) during sleep. We recruited eighteen patients wit...

Substantial night-to-night variability in obstructive sleep apnoea (OSA) severity has raised misdiagnosis and misdirected treatment concerns with the current prevailing single-night diagnostic approach. In-home, multi-night sleep monitoring technology may provide a feasible complimentary diagnostic pathway to improve both the speed and accuracy of...

Effective monitoring of respiratory disturbances during sleep requires a sensor capable of accurately capturing chest movements or airflow displacement. Gold-standard monitoring of sleep and breathing through polysomnography achieves this task through dedicated chest/abdomen bands, thermistors, and nasal flow sensors, and more detailed physiology,...

Introduction Due to misalignment between circadian timing and the work/rest schedule, cognitive performance during night shift-work is often poor. This study tested a circadian-informed lighting strategy designed to improve on-shift cognitive performance through alerting effects, faster circadian adjustment to the shift-work schedule and promoting...

Introduction Approximately 30-50% of people with obstructive sleep apnea (OSA) have difficulty initiating and/or maintaining sleep (DIMS). The co-occurrence of OSA and DIMS is associated with worse mental health and quality of life compared to OSA alone. This study investigated potential associations between OSA and regular sleep disturbances (defi...

Rationale: Oral appliance therapy (OAT) is an effective treatment for many people with obstructive sleep apnea (OSA). However, OSA pathogenesis is heterogenous and in ~50% of cases, OAT does not fully control OSA. Objectives: This study aimed to control OSA in individuals with an incomplete response to OAT alone by using additional targeted ther...

Objective/background: Moderate-to-severe obstructive sleep apnea (OSA) is highly prevalent in children with obesity and/or underlying medical complexity. The first line of therapy, adenotonsillectomy (AT), does not cure OSA in more than 50% of these children. Consequently, continuous positive airway pressure (CPAP) is the main therapeutic option b...

Obstructive sleep apnea (OSA) severity can vary markedly from night-to-night. However, the impact of night-to-night variability in OSA severity on key cardiovascular outcomes such as hypertension is unknown. Thus, the primary aim of this study is to determine the effects of night-to-night variability in OSA severity on hypertension likelihood. This...

Background: Irregularities in sleep duration and sleep timing have emerged as potential risk factors for hypertension. This study examined associations between irregularity in sleep duration and timing with hypertension in a large, global sample over multiple months. Methods: Data from 12 287 adults, who used an under-mattress device to monitor...

Background Snoring may be a risk factor for cardiovascular disease and stroke. However, most prior studies have relied on subjective snoring evaluation from self-reports, or relatively short time-scale objective measures in small samples. This study assessed the prevalence of objectively quantified snoring measured over multiple months, and its ass...

Background: Single-night disease misclassification of obstructive sleep apnea (OSA) due to night-to-night variability may contribute to inconsistent findings in OSA trials. Research question: Does multi-night quantification of OSA severity provide more precise estimates of associations with incident hypertension? Study design and methods: 3831...

Rationale: The combination of noradrenergic and anti-muscarinic agents has recently been shown to improve upper-airway function and reduce obstructive sleep apnea (OSA) severity in short-term (≤1 week) proof-of-concept studies. Objective: To determine the safety, tolerability, and potential efficacy of longer-term use of different doses of the n...

Importance: Chronic breathlessness is common in people with chronic obstructive pulmonary disease (COPD). Regular, low-dose, extended-release morphine may relieve breathlessness, but evidence about its efficacy and dosing is needed. Objective: To determine the effect of different doses of extended-release morphine on worst breathlessness in peop...

Introduction Long term CPAP therapy alters OSA endotypes (e.g., reduces loop gain and the arousal threshold). However, while oral appliance therapy (OAT) is known to improve upper airway collapsibility, its effects on non-anatomical OSA endotypes are unclear. Methods To investigate the effects of OAT on polysomnographic estimates of OSA endotypes...

Introduction People with co-morbid insomnia and sleep apnoea (COMISA) have worse symptoms and require a tailored therapy approach for their sleep disorders. The relationship between the respiratory arousal threshold, a key OSA non-anatomical contributor and insomnia symptoms is unclear. This study investigated the relationship between insomnia symp...

Introduction Irregular sleep has been associated with worse cardio-metabolic health compared to regular sleep, but prior studies are limited in sample size and have assessed sleep irregularity over short assessment periods (7-14 days). This study investigated associations between sleep irregularity and hypertension in a large, global sample over mu...

Background Mandibular advancement splints (MAS) provide effective therapy for many people with OSA. However, in ~50% of cases, MAS alone does not fully resolve OSA. A single-night study showed that ~45% of people with incompletely treated OSA with MAS alone had resolution (apnoea-hypopnea index [AHI]<10 events/h) with the addition of an oral expira...

Mandibular advancement therapy (MAS) is a recognised second-line therapy for obstructive sleep apnoea (OSA). However, MAS treatment outcomes vary and are difficult to predict. Recent studies have investigated the role of OSA endotypes to predict MAS therapy outcomes. However, whether OSA endotype predictors differ between obese and non-obese people...

Introduction Swallowing involves a complex motor pattern and coordination with breathing and other oro-motor behaviors. Sleep has major depressive effect on many of the motor neuronal pools that facilitate swallowing, particularly upper airway muscles. This study examines the state-depedence of the swallow motor program and coordination with breath...

Background Obstructive sleep apnoea (OSA) is as common if not more common in people with multiple sclerosis (MS) versus the general population. However, in contrast to the typical OSA risk factors in the general population, MS is far more common in women versus men, many of whom are not obese. Thus, while some people with MS likely get OSA via the...

Introduction Genioglossus neural drive and the ensuing tongue dilatory movement may be dissociated in obstructive sleep apnoea (OSA), but this has not been studied. This study aimed to investigate this relationship and its potential role in OSA pathophysiology. Methods During awake nasal breathing in the supine position, inspiratory tongue dilator...

Introduction A key predictive mechanism of improvement in obstructive sleep apnoea (OSA) severity with oral appliance therapy (OAT) is a less collapsible upper airway. In this study, we investigate the effects of acute versus longer-term use of OAT on upper airway collapsibility. Methods To investigate potential changes in upper airway collapsibil...

Introduction Shift-work results in misalignment between circadian timing and the sleep/wake schedule, negatively impacting sleep and performance. In encapsulated environments (e.g., submarines), the lack of strong daily lighting cues impairs circadian entrainment. This study tested whether circadian-informed LED lighting promotes greater circadian...

Introduction Low-dose morphine is prescribed for refractory breathlessness in chronic obstructive pulmonary disease (COPD). Preliminary investigations suggest improved perceived sleep quality, although concerns exist regarding opioid-induced sedation. This study assessed the effects of morphine on subjective sleep quality and alertness, and potenti...

Background Oral appliance therapy (OAT) is a well-tolerated treatment for obstructive sleep apnoea (OSA). However, efficacy varies. On average, OAT reduces OSA severity by ~50% leaving a substantial proportion of OAT patients either undertreated or untreated. Thus, a major clinical priority is to develop clinically feasible prediction tools to accu...

Introduction Performance impairments are risky in many industries, including healthcare and defence. Predicting when impairments are more likely to occur is critical to reduce costly workplace accidents and errors. This study created models for predicting vigilance during simulated night shift-work from under-mattress sleep sensor data. Methods Th...

Self-reported sleep difficulties are the primary concern associated with diagnosis and treatment of chronic insomnia. This said, in-home sleep monitoring technology in combination with self-reported sleep outcomes may usefully assist with the management of insomnia. The rapid acceleration in consumer sleep technology capabilities together with thei...

Background K⁺ channel inhibition has been identified in animal models as a potential target to increase pharyngeal dilator muscle activity and treat obstructive sleep apnea (OSA). However, these findings have not yet been translated to humans. Research question Does a novel, potent, TASK 1/3 channel antagonist, BAY2586116, improve pharyngeal colla...

Study objectives: Recent findings indicate that noradrenergic and muscarinic processes are crucial for pharyngeal muscle control during sleep. However, to date, reductions in obstructive sleep apnea (OSA) severity have only been detected when noradrenergic agents are combined with an antimuscarinic. Accordingly, this study aimed to determine if re...

Background Poor sleep quality is associated with increased incident hypertension. However, few studies have investigated the impact of objective sleep structure parameters on hypertension. This study investigated the association between sleep macrostructural and microstructural parameters and incident hypertension in a middle‐ to older‐aged sample....

Tongue and upper airway dilator muscle movement patterns during quiet breathing vary in people with obstructive sleep apnea (OSA). Many patients have inadequate or counterproductive responses to inspiratory negative airway pressure that likely contributes to their OSA. This may be due, at least in part, to inadequate or non-homogeneous reflex drive...

Rationale There are widespread histaminergic projections throughout the brain, including hypoglossal nuclei, that modulate pharyngeal muscle tone and respiratory control. Hence, histaminergic stimulation pharmacologically may increase pharyngeal muscle tone and stabilize respiratory control (loop gain) to reduce obstructive sleep apnea (OSA) severi...

Opioid use continues to rise globally. So too do the associated adverse consequences. Opioid use disorder (OUD) is a chronic and relapsing brain disease characterized by loss of control over opioid use and impairments in cognitive function, mood, pain perception, and autonomic activity. Sleep-deficiency, a term that encompasses insufficient or disr...