Regulatory Control Of The Upper Airway Muscle Genioglossus During Sleep
Funder
National Health and Medical Research Council
Funding Amount
$329,855.00
Summary
Difficulty breathing during sleep is a major health problem. Obstructive Sleep Apnoea (OSA) is the most frequently occurring of these disorders, being found in approximately 4% of males and 2% of females. In OSA the upper airway (UA) collapses during sleep preventing airflow and causing a fall in oxygen levels in the blood. The airway collapses because during sleep muscles in the UA are unable to offset the negative pressure generated within the airway by the effort of inspiring. If the negative ....Difficulty breathing during sleep is a major health problem. Obstructive Sleep Apnoea (OSA) is the most frequently occurring of these disorders, being found in approximately 4% of males and 2% of females. In OSA the upper airway (UA) collapses during sleep preventing airflow and causing a fall in oxygen levels in the blood. The airway collapses because during sleep muscles in the UA are unable to offset the negative pressure generated within the airway by the effort of inspiring. If the negative pressure is too great and the airway collapses the person has to wake up to reopen the airway. As the UA collapses again on the return of sleep, the cycle becomes repetitive, causing sleep disruption. OSA is a significant health risk causing heart disorders, increased mortality, daytime sleepiness, reduced daytime performance and increased risk of accidents. OSA is due to two interacting factors. First, people with a narrow airway have to generate a greater negative pressure during inspiration. Second, and critically, sleep reduces activity in the UA muscles. The importance of this sleep effect is indicated by the observation that OSA patients do not obstruct while awake. Thus, a respiratory abnormality during sleep is a necessary component of the disorder. However, progress in understanding motor control of UA muscles has been slow. We argue that this is in part because research has concentrated on analysing the activity of the UA muscles, rather than measuring the individual motor units that make up the muscles. In this project we propose to investigate the sleep related activity of individual motor units in the UA muscle, genioglossus (GG). GG plays a critical role in the UA as it keeps the tongue from collapsing backwards into the airway. We anticipate that this approach will provide insights into motor control of the tongue and the role of GG in the development of OSA.Read moreRead less
Does Adenotonsillectomy Change Vascular Function In Children With Sleep Breathing Disorders?
Funder
National Health and Medical Research Council
Funding Amount
$522,105.00
Summary
Sleep breathing disorders affect 10% of all children and when severe, obstruction in the upper airways causes serious deficits in growth, development, brain function and heart health. But even mild snoring (without obstruction) may also cause poor health in the arteries that supply blood to the brain and heart, as well as the smaller arteries in the arms and legs. In both adults and children with conditions like diabetes and obesity, poor blood vessel health has been shown to greatly increase th ....Sleep breathing disorders affect 10% of all children and when severe, obstruction in the upper airways causes serious deficits in growth, development, brain function and heart health. But even mild snoring (without obstruction) may also cause poor health in the arteries that supply blood to the brain and heart, as well as the smaller arteries in the arms and legs. In both adults and children with conditions like diabetes and obesity, poor blood vessel health has been shown to greatly increase the future risk of heart attacks, angina and strokes. Children with severe sleep breathing disorders (such as sleep apnoea syndrome) are currently treated by removal of the tonsils and adenoids, which typically resolves snoring and improves sleep, but it is not yet known whether there are any benefits for blood vessel health. The earliest signs of blood vessel disease in children are abnormal function of the lining of the blood vessels (endothelial dysfunction) and thickening of the lining of blood vessels (intima media thickness). They precede the adult diseases of atherosclerosis - which causes heart attacks and strokes, and diabetic kidney and eye disease. These changes can be measured accurately and non-invasively using ultrasound imaging of arteries in the neck and arm. Our primary aim is to assess whether changes in blood vessel health occur in children with sleep breathing disorders across the range of severity, with a secondary aim to measure any changes in cardiovascular control during both sleep (when snoring occurs). Most importantly, by assessing children before and after surgery, we will be able to see for the first time whether treatment of childhood snoring improves blood vessel health. This study may have major implications for the clinical management of snoring children, who may require treatment at an earlier age to prevent poor blood vessel health and an increased risk of cardiovascular diseases later in life.Read moreRead less
Mechanisms Of Apnea And Periodic Breathing In The Newborn.
Funder
National Health and Medical Research Council
Funding Amount
$381,100.00
Summary
Breathing pauses referred to as apnea or periodic breathing occur frequently in the preterm infant, and often require intensive clinical vigilance to ensure survival. And yet the mechanisms that produce and terminate apnea are not understood. This study will investigate the mechanisms underlying infantile apnea and periodic breathing and the effectiveness of drugs and techniques currently used to control apnea by using a combination of infant animal model studies, mathematical modelling studies ....Breathing pauses referred to as apnea or periodic breathing occur frequently in the preterm infant, and often require intensive clinical vigilance to ensure survival. And yet the mechanisms that produce and terminate apnea are not understood. This study will investigate the mechanisms underlying infantile apnea and periodic breathing and the effectiveness of drugs and techniques currently used to control apnea by using a combination of infant animal model studies, mathematical modelling studies and studies in human preterm infants to improve our understanding of breathing control in infancy.Read moreRead less
Alternatives To Polysomnography For Children With Suspected Obstructive Sleep Apnoea.
Funder
National Health and Medical Research Council
Funding Amount
$357,613.00
Summary
Snoring is the cardinal symptom of obstructive sleep apnoea (OSA), a major health issue in childhood with significant impacts on cognition, behaviour and cardiovascular health. Approximately 35% of children snore but only about 10% of those have OSA. Defining OSA in a snoring child requires polysomnography, a technically challenging and expensive test. In this study we will examine a number of simple tests for their predictive power for OSA, developing a tool that will enable clinicians to diagn ....Snoring is the cardinal symptom of obstructive sleep apnoea (OSA), a major health issue in childhood with significant impacts on cognition, behaviour and cardiovascular health. Approximately 35% of children snore but only about 10% of those have OSA. Defining OSA in a snoring child requires polysomnography, a technically challenging and expensive test. In this study we will examine a number of simple tests for their predictive power for OSA, developing a tool that will enable clinicians to diagnose OSA without the need for polysomnography.Read moreRead less
Pressures Exerted On Upper Airway Walls By Surrounding Tissue Structures
Funder
National Health and Medical Research Council
Funding Amount
$426,500.00
Summary
The obstructive sleep apnoea syndrome (OSA) refers to a condition in which throat blockage occurs during sleep leading to breathing difficulties, including cessation of breathing for short periods of time. OSA effects both men and women but is amongst the commonest of chronic disorders of adult males, occurring in 5% of men over the age of 45 years. In the proposed studies we will examine the effect of the pressure in the tissues surrounding the throat on the ability of the throat to stay open a ....The obstructive sleep apnoea syndrome (OSA) refers to a condition in which throat blockage occurs during sleep leading to breathing difficulties, including cessation of breathing for short periods of time. OSA effects both men and women but is amongst the commonest of chronic disorders of adult males, occurring in 5% of men over the age of 45 years. In the proposed studies we will examine the effect of the pressure in the tissues surrounding the throat on the ability of the throat to stay open and allow breathing. The major outcome of the animal studies is increased knowledge concerning mechanisms whereby collapsing forces are applied to the upper airway. This will give insights into potential factors influencing upper airway collapse during sleep in OSA patients. Of particular importance will be our studies on the effects of jaw position on the pressure exerted on the walls of the throat since the use of an intra-oral device to hold the jaw forward during sleep is one of the treatments used to prevent throat blockage during sleep. The studies in humans will examine, for the first time, the notion that the mass (weight) of the neck has a direct effect on the severity of sleep disordered breathing. If neck mass has a substantive influence on sleep disordered breathing then strategies aimed at reducing neck mass (fat) may provide a new therapeutic approach to the management of OSA patients.Read moreRead less
If Childhood Primary Snoring Resolves, Do Neurocognition And Behaviour Also Improve?
Funder
National Health and Medical Research Council
Funding Amount
$568,067.00
Summary
Sleep breathing disorders (SBD) are common and affect around 10% of all children. Previous research however has shown that sleep disorders are often not recognised or considered important enough to report to general practitioners. Thus, the true incidence of sleep disorders in Australian children is not known. Nevertheless, even the mildest SBD, primary snoring, has been associated with significant deficits in daytime learning, memory, intelligence, attention and problematic behaviour. In severe ....Sleep breathing disorders (SBD) are common and affect around 10% of all children. Previous research however has shown that sleep disorders are often not recognised or considered important enough to report to general practitioners. Thus, the true incidence of sleep disorders in Australian children is not known. Nevertheless, even the mildest SBD, primary snoring, has been associated with significant deficits in daytime learning, memory, intelligence, attention and problematic behaviour. In severe cases of childhood SBD (i.e. sleep apnoea syndrome), removal of the tonsils and adenoids has been shown to improve the learning and behaviour problems. Thus there is increasing pressure on doctors to treat primary snoring in children with surgery to improve their intellectual functioning. However, recent evidence in children has shown that snoring may resolve naturally in up to 50% of cases over one to two years. In addition to the risks of surgery, the large number of children who may have a natural resolution of snoring suggestst that the pressure to treat primary snoring in may not be justified. This study will be the first to determine the prevalence of childhood snoring and associated problems in the Australian community. We also aim to discover whether snoring and the associated intellectual deficits persist over time during childhood. We will identify frequent snorers and healthy non-snorers in children aged 5-10 years old, using parental questionnaires. We will then study 75 snorers and 75 non-snorers in more detail, monitoring them with overnight sleep studies and questionnaires 2 years apart, to see if snoring, intellectual function and behavioural problems persist over time. This information will improve the health of Australian children by determining the prevalence of childhood SBD and persistence of associated deficits such as in learning, memory and behaviour.Read moreRead less
THE BAROREFLEX IN SNORING AND THE OBSTRUCTIVE SLEEP APNOEA HYPOPNOEA SYNDROME
Funder
National Health and Medical Research Council
Funding Amount
$436,261.00
Summary
The obstructive sleep apnoea hypopnoea syndrome (OSAHS) refers to a condition in which throat blockage occurs during sleep leading to breathing difficulties, including snoring and cessation of breathing for short periods of time. OSAHS is amongst the commonest of chronic disorders of adult males, occuring in 5% of men over the age of 45 years. It is now recognised that one of the major complications of OSAHS is the development of high blood pressure and heart disease. In the proposed studies, we ....The obstructive sleep apnoea hypopnoea syndrome (OSAHS) refers to a condition in which throat blockage occurs during sleep leading to breathing difficulties, including snoring and cessation of breathing for short periods of time. OSAHS is amongst the commonest of chronic disorders of adult males, occuring in 5% of men over the age of 45 years. It is now recognised that one of the major complications of OSAHS is the development of high blood pressure and heart disease. In the proposed studies, we will examine the proposal that snoring alone, without significant associated OSAHS, can also lead to high blood pressure in habitual snorers both awake and asleep. In particular, we will explore the hypothesis that chronic snoring transmits a pressure wave through the tissues of the neck to the carotid artery which is the main blood supply to the brain. We propose that the chronic vibration of this artery can alter pressure sensors in the artery wall, which then results in the persistance of high blood pressure. Our studies will help to prove that this is a mechanism whereby both snoring and OSAHS may contribute to the development of high blood pressure. The recognition of snoring as an independent risk factor for high blood pressure will clearly have important and wide ranging implications for the future management of snoring in the prevention of high blood pressure.Read moreRead less
The Impact Of CPAP Treatment On Carotid Artery Atherosclerosis In Heavy Snoring And Mild Sleep Disordered Breathing
Funder
National Health and Medical Research Council
Funding Amount
$697,512.00
Summary
Mild sleep disordered breathing, including habitual snoring, is a very common problem in the adult population, with a prevalence of between 20-40%. Increasingly it is now recognised that habitual snoring may be an independent risk factor for the development of stroke. In this proposal we will explore the hypothesis that treatment for snoring will slow or stop the development of carotid artery atherosclerosis.