Track topics on Twitter Track topics that are important to you
Obstructive sleep apnea (OSA) is a prevalent sleep breathing disorder in the general population in which recurrent collapse of the upper airway occurs during sleep. OSA is more prevalent in subjects with stroke and is associated with a 3 fold increased risk of stroke. This makes it a serious public health problem. Approximately 50% of subjects with OSA are asymptomatic and are often only detected following investigation for the cause of heart disease or a stroke. In subjects who are treated for OSA many are intolerant or poorly compliant with treatment. Therefore, the identification of those subjects with OSA most at risk of adverse consequences such as stroke is important, so that treatment compliance can be improved.
Therfore, the investigators want to determine if compared to subjects without OSA, subjects with OSA have evidence of increased stroke risk by assessment of changes in cerebral blood flow (cerebrovascular reactivity) as measured on Doppler ultrasound of the middle cerebral artery (TCD) and blood oxygen level-dependent magnetic resonance imaging of patterns of cerebral blood flow (BOLD MRI) to two stimuli. These stimuli include increased carbon dioxide concentrations (causes increased cerebral blood flow) and reduced oxygen concentrations (causing decreased cerebral blood flow). In order to deliver these stimuli the investigators will use a special machine (RespiractTM) which allows for the precise control of carbon dioxide and oxygen concentrations in the lungs and blood. The precise control of carbon dioxide and oxygen in conjunction with BOLD MRI has enabled the production of detailed maps of the brain that identify areas of healthy and abnormal blood supply.
OSA is associated with increased risk of cardiovascular and cerebrovascular disease compared to the general population. The mechanism for the increased stroke risk in OSA is unknown. However, the constellation of adverse pathophysiological consequences, including intermittent hypoxia and carbon-dioxide retention as a result of OSA may be detrimental to CVR and predispose the brain to ischemia. Previous studies in OSA subjects have measured CVR only using TCD. Therefore, our study will examine CVR by two methods (TCD and BOLD-MRI) with reliable and reproducible hypercapnia and independent control of oxygen saturation (RespiractTM). Patterns seen on CVR may eventually allow the identification of OSA patients who will be at greatest risk for stroke and will therefore, require aggressive risk reduction and/or treatment irrespective of symptoms.
Observational Model: Cohort, Time Perspective: Prospective
Toronto Gneral Hospital
University Health Network, Toronto
Published on BioPortfolio: 2014-08-27T03:13:20-0400
Sleep apnea is common in acromegaly and both diseases are independently associated with hypertension and insulin resistance contributing to increased morbidity and mortality. Respiratory p...
Sleep apnea is a prevalent disorder in patients with coronary artery disease. Previous studies suggested sleep apnea was associated with coronary plaque burden and future adverse cardiovas...
This is a research study of asthma and sleep apnea. Our hypothesis is that untreated sleep apnea causes inflammation in the lung, which can worsen asthma. We believe treatment of sleep a...
Sleep studies in ESRD patients have identified increased prevalence of Sleep Apnea. Based on current knowledge, treatment aimed at reducing oxidative stress might improve Sleep Apnea in HD...
The purpose of this pilot study is to determine the feasibility of using a novel treatment for sleep apnea in which the patient's own exhaled CO2 is tightly controlled and used in a rebrea...
Sleep apnea is an underdiagnosed condition in patients with heart failure. Efficient identification of sleep apnea is needed as treatment may improve heart failure-related outcomes. Currently, use of ...
Sleep apnea has been associated with anxiety, but the mechanisms of the sleep apnea-anxiety relationship are unresolved. Sleep apnea causes oxidative stress, which might enhance anxiety-like behavior ...
Sleep apnea is associated with hypertension, and treatment may improve outcomes. We examine national burden of sleep apnea, rates of sleep apnea treatment, and whether racial/ethnic disparities exist ...
Home sleep apnea testing (HSAT) is a diagnostic measure for obstructive sleep apnea hypopnea syndrome (OSAHS) in moderate/high risk patients. Some HSAT companies contain automatic analysis (AA). Howev...
Obstructive Sleep Apnea (OSA) contributes to all-cause mortality. An American Academy of Sleep Medicine task force is focusing on improving detection and categorization of OSA symptoms and severity to...
A condition associated with multiple episodes of sleep apnea which are distinguished from obstructive sleep apnea (SLEEP APNEA, OBSTRUCTIVE) by the complete cessation of efforts to breathe. This disorder is associated with dysfunction of central nervous system centers that regulate respiration. This condition may be idiopathic (primary) or associated with lower brain stem lesions; chronic obstructive pulmonary disease (LUNG DISEASES, OBSTRUCTIVE); HEART FAILURE, CONGESTIVE; medication effect; and other conditions. Sleep maintenance is impaired, resulting in daytime hypersomnolence. Primary central sleep apnea is frequently associated with obstructive sleep apnea. When both forms are present the condition is referred to as mixed sleep apnea (see SLEEP APNEA SYNDROMES). (Adams et al., Principles of Neurology, 6th ed, p395; Neurol Clin 1996;14(3):611-28)
Disorders characterized by multiple cessations of respirations during sleep that induce partial arousals and interfere with the maintenance of sleep. Sleep apnea syndromes are divided into central (see SLEEP APNEA, CENTRAL), obstructive (see SLEEP APNEA, OBSTRUCTIVE), and mixed central-obstructive types.
Dyssomnias (i.e., insomnias or hypersomnias) associated with dysfunction of internal sleep mechanisms or secondary to a sleep-related medical disorder (e.g., sleep apnea, post-traumatic sleep disorders, etc.). (From Thorpy, Sleep Disorders Medicine, 1994, p187)
A disorder characterized by recurrent apneas during sleep despite persistent respiratory efforts. It is due to upper airway obstruction. The respiratory pauses may induce HYPERCAPNIA or HYPOXIA. Cardiac arrhythmias and elevation of systemic and pulmonary arterial pressures may occur. Frequent partial arousals occur throughout sleep, resulting in relative SLEEP DEPRIVATION and daytime tiredness. Associated conditions include OBESITY; ACROMEGALY; MYXEDEMA; micrognathia; MYOTONIC DYSTROPHY; adenotonsilar dystrophy; and NEUROMUSCULAR DISEASES. (From Adams et al., Principles of Neurology, 6th ed, p395)
Periods of sleep manifested by changes in EEG activity and certain behavioral correlates; includes Stage 1: sleep onset, drowsy sleep; Stage 2: light sleep; Stages 3 and 4: delta sleep, light sleep, deep sleep, telencephalic sleep.
Sleep disorders disrupt sleep during the night, or cause sleepiness during the day, caused by physiological or psychological factors. The common ones include snoring and sleep apnea, insomnia, parasomnias, sleep paralysis, restless legs syndrome, circa...
Stroke - Cerebrovascular Disease (CVA)
A stroke is a serious medical condition that occurs when the blood supply to part of the brain is cut off. Strokes are a medical emergency and prompt treatment is essential because the sooner a person receives treatment for a stroke, the less damage is ...
Neurology - Central Nervous System (CNS)
Alzheimer's Disease Anesthesia Anxiety Disorders Autism Bipolar Disorders Dementia Epilepsy Multiple Sclerosis (MS) Neurology Pain Parkinson's Disease Sleep Disorders Neurology is the branch of me...