Investigating the Neuropathology of Obstructive Sleep Apnoea

This is a cross-sectional physiological study, which is anticipated to last for 4 years. In order to study the mechanism of cognitive dysfunction in Obstructive Sleep Apnoea (OSA), patients will start Continuous Positive Airway Pressure (CPAP) treatment following the confirmed diagnosis of sleep apnoea. CPAP is the treatment of choice for patients with moderate to severe OSA who are sleepy during the day. It is also used in patients with mild OSA if they are excessively sleepy or suffer from cardiovascular risk factors. It is recommended by the National Institute for Clinical Excellence (NICE) as a treatment for adults with moderate or severe OSA (Sleep apnoea - continuous positive airway pressure, NICE 2008). In the proposed study the initiation of CPAP will be within the 18 week period set out in the National Health Service (NHS) Improvement Plan and Standards for Better Health (Standards for Better Health, Department of Health 2004). No patient with a diagnosis of OSA will commence treatment with CPAP later than advised by the NICE guidelines of clinical judgement for the best interest of the patient. In order to investigate the neuroinflammation process and discrete changes in the brain of patients with OSA, a minimum of 9 patients with mild OSA and 9 patients with severe OSA will be compared to 9 healthy controls following initial sleep (assessment) study. All participants will undergo a dynamic Positron Emission Tomography with Magnetic Resonance Imaging (PET-MR) scan with the Translocator protein (TSPO) tracer \[Fluorine-18\] N,N-diethyl-2-\[4-(2-fluoroethoxy)phenyl\]-5,7-dimethylpyrazolo\[1,5-a\]pyrimidine-3-acetamide (DPA-714) at the time of enrolment to the study. Each participant will also have an MRI scan and cognitive testing.