Upper Airway Dilator Muscle Activity During Sleep Onset.
Funder
National Health and Medical Research Council
Funding Amount
$211,320.00
Summary
Disorders of breathing during sleep are recognised as a major health problem. Of these, Obstructive Sleep Apnoea is the most prevalent, occurring in approximately 4% of the male and 2% of the female population. In this disorder the upper airway collapses during sleep causing cessation of airflow and subsequent oxygen desaturation. The airway is thought to occlude because dilator muscles are unable to sustain patency in the face of the negative pressures generated by inspiratory effort. In order ....Disorders of breathing during sleep are recognised as a major health problem. Of these, Obstructive Sleep Apnoea is the most prevalent, occurring in approximately 4% of the male and 2% of the female population. In this disorder the upper airway collapses during sleep causing cessation of airflow and subsequent oxygen desaturation. The airway is thought to occlude because dilator muscles are unable to sustain patency in the face of the negative pressures generated by inspiratory effort. In order for patency of the airway to be re-established some form of arousal from sleep must occur . As the UA is likely to collapse on the resumption of sleep, the cycle becomes repetitive, causing significant sleep disruption. OSA is a significant health risk, being associated with increased risk of cardiovascular disorders, increased mortality, excessive daytime sleepiness, reduced daytime performance and increased risk of accidents. In previous work we have demonstrated that normal sleep related changes in the activity of upper airway dilator muscles result in a reduction in the calibre of the airway at sleep onset. This exposes some individuals, such as those with narrow airways, to airway obstruction during sleep. We have also reported that elderly men have larger reductions in upper airway muscle activity at sleep onset than younger men, suggesting one reason why they may have a higher prevalence for Obstructive Sleep Apnea. The aim of the present project is to determine what causes the larger reductions in upper airway muscle activity in older males. The answer to this question will contribute to understanding why this group is so susceptible to Obstructive Sleep Apnea and will elucidate the mechanisms leading to the disorder.Read moreRead less
The Influence Of Sleep On The Behaviour Of The Upper Airway Muscles, Genioglossus And Tensor Palatini
Funder
National Health and Medical Research Council
Funding Amount
$295,880.00
Summary
The human airway has limited bone or cartilage support and muscular activity is required to keep the airway open. Central activation of these muscles is reduced during sleep, resulting in the disorder Obstructive Sleep Apnoea. Potential treatments include pharmocological or electrical stimulation of upper airway muscles. However, this is hampered by a lack of understanding of the control of upper airway muscles. This project will study two critical muscles, genioglossus and tensor palatini.
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
Sleep Disordered Breathing In Pregnancy: Frequency And Impact.
Funder
National Health and Medical Research Council
Funding Amount
$607,034.00
Summary
Sleep disordered breathing (SDB)affects up to 15% of women during pregnancy. There is some evidence that it may have adverse effects on both mother and baby, particularly it may be associated with a 7-8 fold increase risk of developing hypertension during pregnancy. This study aims to measure breathing during sleep in pregnant women to determine its role in pregnancy-related hypertension and diabetes, then treat the SDB to assess its effect on maternal and foetal outcomes.
Neurobiological Effects Of Sleep Apnea And Sleepiness
Funder
National Health and Medical Research Council
Funding Amount
$320,437.00
Summary
Sleep apnea affects over one million Australians. It not only affects the quality of a persons sleep and the oxygen supply to their brain, but can cause sleepiness during the day which can in turn affect the ability of the person to conduct their normal activities. Over 30,000 sleep studies are conducted annually in Australia and current therapies result in significant improvements in the quality of life of the patient. However, the data analysis during these studies does not give a clear indica ....Sleep apnea affects over one million Australians. It not only affects the quality of a persons sleep and the oxygen supply to their brain, but can cause sleepiness during the day which can in turn affect the ability of the person to conduct their normal activities. Over 30,000 sleep studies are conducted annually in Australia and current therapies result in significant improvements in the quality of life of the patient. However, the data analysis during these studies does not give a clear indication of the degree to which individual patients may have problems with performing their normal tasks during the day. Tasks like driving vehicles are of particular interest due to the potential for accidents through fatigue or a lack of concentration. This research is designed to investigate the impact of sleep apnea on brain function and daytime performance using certain new techniques - more sophisticated analysis of the brain's activity, detection of brain chemicals and metabolism using a specific form of brain scan called MR spectroscopy, a special monotonous computer based driving simulator, an other tests of performance. We will assess a large group of patients with sleep apnea to determine how the impact of sleep apnea on performance may be differ throughout the population and how this may be affected by the current standard treatment for sleep apnea. We will examine the impact on brain function and performance of removing the current standard therapy in a group of patients previously diagnosed with sleep apnea (as this is a common occurrence in the community). We will also repeat some specific measurements on a control group without any symptoms of sleep apnea for the purpose of comparison. We plan to show a relationship between the effects of sleep apnea and the ability of a person to carry out activities such as driving and thinking. We will then be able to better assess the risk a patient may face and the most appropriate way to treat them.Read moreRead less
The Role Of Arousal And Respiratory Control Factors In The Pathogenesis Of Obstructive Sleep Apnoea
Funder
National Health and Medical Research Council
Funding Amount
$567,924.00
Summary
Sleep apnoea (OSA) is a very common breathing disorder in sleep characterized by repetitive closure of the collapsible portion of the throat with serious effects on sleep quality and health. Basic causes of OSA are still largely unknown. We will investigate waking responses to breathing load and related respiratory control factors that we believe may be fundamental causes of OSA, and potentially explain many features of OSA including worsening in light sleep and with increasing age.
A Randomised Controlled Trial Of A Simplified Management Strategy Versus Standard Care In Moderate To Severe OSA
Funder
National Health and Medical Research Council
Funding Amount
$561,400.00
Summary
Currently breathing difficulties during sleep known as obstructive sleep apnea (OSA) are undertreated in our community. This reflects an inability of the current diagnostic and treatment strategies to deal with the high clinical burden of OSA. As a result, in particular in rural and remote areas, many have long waits for treatment, or no access to therapy at all. The purpose of this project is to evaluate a simplified protocol for the management of OSA. This will be done using diagnostic devices ....Currently breathing difficulties during sleep known as obstructive sleep apnea (OSA) are undertreated in our community. This reflects an inability of the current diagnostic and treatment strategies to deal with the high clinical burden of OSA. As a result, in particular in rural and remote areas, many have long waits for treatment, or no access to therapy at all. The purpose of this project is to evaluate a simplified protocol for the management of OSA. This will be done using diagnostic devices and treatment strategies that are more widely available than the current approaches to the diagnosis and management of obstructive sleep apnea. This will involve measurement of the numbers of falls in oxygen levels in a patient via a device to measure oxygen levels called an oximeter. These falls in oxygen levels correlate well with breath holding episodes during sleep characteristic of OSA. Treatment can be commenced in the patient's home depending on these results. We intend to compare these new approaches with the current best practice in OSA. If the outcomes are good these stategies could be applied to reduce the waiting times for to diagnose and manage OSA and make therapy more widely available throughout the community.Read moreRead less
Surface Tension Of Upper Airway Lining Liquid: Role In Obstructive Sleep Apnoea Hyponoea Syndrome
Funder
National Health and Medical Research Council
Funding Amount
$494,833.00
Summary
The obstructive sleep apnoea hypopnoea syndrome (OSAHS) refers to a condition in which throat blockage occurs during sleep leading to breathing difficulties, including cessation of breathing for short periods of time. OSAHS affects 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 that the liquid layer that lines the throat, has on the ability of the airway to st ....The obstructive sleep apnoea hypopnoea syndrome (OSAHS) refers to a condition in which throat blockage occurs during sleep leading to breathing difficulties, including cessation of breathing for short periods of time. OSAHS affects 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 that the liquid layer that lines the throat, has on the ability of the airway to stay open during sleep. In particular we will examine whether coating the throat with a substance that decreases stickiness will help to prevent the occurrence of episodes of throat blockage during sleep in persons with OSAHS. We will also explore the role of saliva production and swallowing during sleep in maintaining a low stickiness of the throat and whether this liquid lining is abnormal in OSAHS patients. These studies will establish the potential usefulness of decreasing the stickiness of the liquid lining the throat as a treatment for OSAHS.Read moreRead less
Interaction Between Sleep Apnea And Metabolic Syndrome
Funder
National Health and Medical Research Council
Funding Amount
$423,650.00
Summary
In this proposal, we will study possible ways in which sleep disordered breathing (snoring sickness or sleep apnea) may cause or worsen metabolic syndrome. Sleep apnea is a common disorder frequently linked to metabolic syndrome. Metabolic syndrome is a cluster of health risk factors including increased risk of diabetes, high cholesterol, high blood pressure and excess fat around the abdomen. Metabolic syndrome is an important cause of increased death from cardiovascular disease and affects abou ....In this proposal, we will study possible ways in which sleep disordered breathing (snoring sickness or sleep apnea) may cause or worsen metabolic syndrome. Sleep apnea is a common disorder frequently linked to metabolic syndrome. Metabolic syndrome is a cluster of health risk factors including increased risk of diabetes, high cholesterol, high blood pressure and excess fat around the abdomen. Metabolic syndrome is an important cause of increased death from cardiovascular disease and affects about 3 million Australians. Our theory is that lack of oxygen during sleep and disruption of normal sleep patterns leads to increased activity of the body stress handling systems and damage to the lining of the body's blood vessels. In turn, this may promote high blood fat levels and cause excess fat deposits in muscle and liver. We will measure blood, muscle and liver fat changes with treatment of sleep apnea. We believe that by damaging the lining of blood vessels, sleep apnea will also cause an inability of the body's arteries to relax properly. We will measure sleep apnea and the ability of the body's arteries to expand using novel techniques before and after treatment of sleep apnea. We will also take people off treatment to see if these changes get worse. Part of the proposal includes investigating whether snoring and lack of oxygen during sleep leads to increased blood fat levels. Finally, in another study, we will measure the change in metabolic syndrome related disorders in people with sleep apnea losing weight.Read moreRead less
The Role Of Arousal And Diaphragm Displacement In The Pathogenesis Of Obstructive Sleep Apnoea
Funder
National Health and Medical Research Council
Funding Amount
$410,875.00
Summary
Obstructive sleep apnea (OSA) affects 4% of men and causes excessive daytime sleepiness leading to increased accidents, high blood pressure and premature cardiovascular disease e.g. heart attacks and strokes. OSA is characterized by repetitive obstructions of the floppy portion of the throat during sleep with adverse effects on oxygen levels and sleep quality. OSA is strongly associated with obesity and is 2-3 times more common in men than women. How obesity and male gender predispose to OSA is ....Obstructive sleep apnea (OSA) affects 4% of men and causes excessive daytime sleepiness leading to increased accidents, high blood pressure and premature cardiovascular disease e.g. heart attacks and strokes. OSA is characterized by repetitive obstructions of the floppy portion of the throat during sleep with adverse effects on oxygen levels and sleep quality. OSA is strongly associated with obesity and is 2-3 times more common in men than women. How obesity and male gender predispose to OSA is not known. We will investigate two factors that we believe are most likely involved in causing and explaining this gender difference in OSA. We will examine if breathing responses with brief awakening are sufficient to promote OSA patterns of breathing in snorers and if they are greater in male than female OSA patients. We have already shown that healthy men have greater breathing response to arousal compared to women. These brief arousals occur hundreds of times a night in OSA patients, and over-breathing on arousal may increase the probability of upper airway obstruction on falling back to sleep. We will also investigate why even healthy men show greater breathing responses compared to women. Men tend to accumulate fat centrally, particularly in the abdomen, whereas in women fat tends to be distributed more to the hips and thighs. This could be very important in OSA because downward pull exerted on the upper airway by the diaphragm is likely to be reduced in people with more abdominal obesity. This mechanisms has not yet been studied in humans. We will therefore investigate if increased forces placed on the diaphragm during sleep make the upper airway more prone to collapse. We will also investigate these effects during sleep onset, when there may well be important changes in diaphragm position as muscles relax.Read moreRead less