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.
Evaluation Of A Rapid Behavioural Treatment For Sleep Onset Insomnia
Funder
National Health and Medical Research Council
Funding Amount
$268,500.00
Summary
Chronic insomnia is a prevalent health problem that affects 5-10% of the population. It is associated with significant physical and mental health problems as well as lowered quality of life. By far the most common treatment for insomnia continues to be sleeping tablets despite the problems of drug dependence, daytime impairment and long term loss of effect. It is also despite the evidence that behavioural therapies are more effective in the long term. In clinical experiments stimulus control the ....Chronic insomnia is a prevalent health problem that affects 5-10% of the population. It is associated with significant physical and mental health problems as well as lowered quality of life. By far the most common treatment for insomnia continues to be sleeping tablets despite the problems of drug dependence, daytime impairment and long term loss of effect. It is also despite the evidence that behavioural therapies are more effective in the long term. In clinical experiments stimulus control therapy (SCT) is consistently the most effective of the behavioural therapies. However, SCT is difficult to carry out over the 4-6 week period necessary for effective treatment. If the treatment process could be shortened, it may increase the number of successful treatments. We have developed a laboratory procedure which includes the effective elements of SCT. These elements include sleep restriction and the experience of one rapid sleep onset each night. Our procedure involves some sleep deprivation and the experience of many (over 40) rapid sleep onsets over just one day. Therefore, it condenses 40 nights of the re-training benefits of SCT into just one day. A preliminary study has shown this procedure to be as effective as normal SCT. However, with no follow-up therapy to the procedure the initial gains tended to diminish with time. Our proposal is to test and extend the possible benefits of this new treatment procedure. We will compare it with the standard SCT as well as combine it with SCT. We feel that the greatest benefit may be to use the laboratory procedure as a kick start to SCT, which will by-pass the most difficult first 2--3 weeks of SCT. This will greatly reduce the time as well as absolutely improve the outcome. In further studies the laboratory procedure may be transferred to the patient s home, thereby further increasing its effectiveness. We feel the proposal will lead to a significant improvement in the non-drug treatment of insomnia.Read moreRead less
Phase Shifting Endocrine And Sleep/activity Rhythms With Light And Serotonergic Drugs
Funder
National Health and Medical Research Council
Funding Amount
$561,430.00
Summary
All biological systems, including those of humans, are influenced by changes in the environment, especially by variations in the amount of daylight. In animals the external rhythm of light and darkness interacts with a small part of the brain called the suprachiasmatic nucleus (SCN-often called the biological clock) which has its own self sustained rhythms. The SCN in turn orchestrates rhythms in the secretion of the hormone melatonin from the pineal gland, body temperature, the timing of sleep ....All biological systems, including those of humans, are influenced by changes in the environment, especially by variations in the amount of daylight. In animals the external rhythm of light and darkness interacts with a small part of the brain called the suprachiasmatic nucleus (SCN-often called the biological clock) which has its own self sustained rhythms. The SCN in turn orchestrates rhythms in the secretion of the hormone melatonin from the pineal gland, body temperature, the timing of sleep and the secretion of other hormones. The aim of this study is to extend our knowledge of the inter-relationships between light, the chemical messengers that nerves use to communicate with each other, the biological clock and rhythms in body functions. We will concentrate on one particular chemical messenger called serotonin which we believe plays an important role in keeping rhythms in synchrony with the natural day-night cycle. The results are expected to be of benefit in understanding how certain sleep timing disorders arise and provide some insight into how they might be treated.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
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
Impact Of Sleep Disordered Breathing On Cardiovascular, Behavioural And Neurocognitive Function In Preschool Children
Funder
National Health and Medical Research Council
Funding Amount
$425,703.00
Summary
Studies in school age children have shown that disruption to normal sleep patterns resulting from sleep disordered breathing (SDB) has severe consequences for both the cardiovascular system and neurocognition. To date there have been limited investigations of the effects of SDB in pre-school children despite the knowledge that disruptions to breathing during sleep are maximal at this age and the central nervous system which is immature and developing at this time, is most vulnerable to injury.