Sleep apnoea

HEALTH INFORMATION

Improving treatments for obstructive sleep apnoea

WHAT WE KNOW

Obstructive sleep apnoea is more than just an extreme form of snoring. In this disorder, the muscles in the throat and upper airway repeatedly collapse while you sleep, leading to a decrease in the amount of oxygen in your blood. This also partially rouses you from sleep many times a night and leads to poor sleep and an increased risk of accidents, hypertension, heart attack and stroke.

While there are several treatments available for obstructive sleep apnoea, we don’t truly understand how the muscles of the upper airway cause the condition.

We are currently making the first direct biomechanical measurements of the upper airway in humans. By examining how the mechanical properties of these muscles are altered in people with obstructive sleep apnoea and how the brain drives these muscles, we will be able to improve treatments.

OUR LATEST RESEARCH

Causes of sleep apnoea in people with and without multiple sclerosis (MS)

This project, sponsored by MS research Australia, focuses on sleep apnoea in people with multiple sclerosis (MS). Our recent study, amongst other studies, suggests that sleep apnoea rates are higher in people with MS. However little is known about the causes of sleep apnoea in people with MS and how they might be different from people without MS. This project involves a sleep study including physiological measurements to identify differences in the causes of sleep apnoea between people with and without MS.

The Effects of "Z Drugs" in People With Obstructive Sleep Apnoea

Obstructive sleep apnoea (OSA) is a common disorder characterised by repetitive narrowing and collapse of the upper airway during sleep. It is associated with daytime sleepiness, neurocognitive impairment, and a variety of adverse cardiovascular consequences. The first line treatment for OSA is continuous positive airway pressure (CPAP) therapy. If tolerated, CPAP is highly effective in reducing sleep disordered breathing events. However, up to 50% of OSA patients are unable to tolerate CPAP therapy leaving many OSA patients without treatment.

Previous studies indicate that in selected obstructive sleep apnea participants a standard dose of a z-drug can shift the threshold for awakening during sleep (arousal) whilst maintaining the upper airway muscle activity required to keep the airway open. This study aims to investigate the effects of different doses of sleeping pills (Z-drugs) on how easily people wake up when the airway narrows during sleep, the activity of a major muscle located under the tongue (genioglossus) and obstructive sleep apnoea (OSA) severity and symptoms.

Effects of Noradrenergic and Antimuscarinic agents on Sleep Apnoea Severity

Approximately 1/3 of all obstructive sleep apnoea (OSA) patients have poor upper airway muscle activity during sleep which contributes to the repetitive narrowing or closure of the airway during sleep. This leads to abrupt arousals and disruption of sleep throughout the night which can lead to various health problems including diabetes, cardiovascular diseases, obesity, high blood pressure, impaired cognitive function, decreased quality of life and patients are more likely to be involved in motor vehicular accidents.

Recent studies have found that combination of these noradrenergic and antimuscarinic agents help to improve upper airway muscle activity during sleep. Therefore, this clinical study will focus on determining the effects of these agents on the severity of sleep apnoea in OSA patients in hopes to improve treatment outcomes for OSA patients in the future. The study also aims to determine the effects of these combination of agents on cognitive alertness and other sleep parameters which are impaired in patients with OSA.

The effect of respiratory muscle training on respiratory health after spinal cord injury

After cervical spinal cord injury (SCI), the respiratory muscles are partly or completely paralysed. This has two major clinical consequences: a decreased ability to get air into the lungs and a decreased ability to cough and remove secretions. This results in a lifetime of recurrent respiratory tract infections (2/year/person) that often progress to pneumonia with frequent and extended hospital admissions. People with cervical SCI are 150 times more likely to die from respiratory complications than the general population, as many as 28% die within the first year after injury. For those that survive the first year, a cervical SCI has a lifetime cost of $9.5million, a large proportion of which is attributed to respiratory-related complications. A recent longitudinal study of people with cervical SCI showed that respiratory muscle weakness is associated with incidental pneumonia. Respiratory muscle weakness also causes dyspnoea (breathlessness) and sleep-disordered breathing, which is 4-10 times more prevalent in people with SCI than the able-bodied population. Therefore, there is an urgent need to identify a simple and cost-effective treatment for respiratory muscles weakness to prevent respiratory complications after SCI, improve quality of life and reduce the burden on the healthcare system.

Our primary aim is to determine definitively the effectiveness of training on respiratory muscle strength, respiratory physiology and health outcomes. To do this we will conduct a randomised controlled trial 2 times bigger than the largest previous study, of respiratory muscle resistive load training in individuals with acute and chronic cervical SCI. The project will provide critical new knowledge about the efficacy of a simple and inexpensive respiratory muscle training regime, which can be applied immediately in the hospital and community, to minimise respiratory morbidity in people with SCI. This project also provides a unique opportunity to investigate other consequential effects of long-term respiratory muscle training that have never been studied in people with SCI. These include effects on cough efficacy, sleep-disordered breathing, breathlessness, respiratory morbidity, respiratory health and neural drive to the diaphragm, as well as quality of life.

Obstructive Sleep Apnoea Imaging

We have developed novel imaging methods to measure the stiffness and movement of the upper airway muscles, and are using these together with measures of pharyngeal sensation, and electromyography to determine the patient-specific causes of obstructive sleep apnoea. We aim to use this information to tailor treatments for patients. One such treatment is a mandibular advancement splint, but currently it’s not possible to predict who will benefit from use a splint. We have a major project that aims to predict splint treatment outcome, based on our novel imaging methods.• Honours and PhD projects are available to study the neural, biomechanical and physiological aspects of obstructive sleep apnoea, including computational modelling

What else is happening in Sleep apnoea research at NeuRA?

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