As is usual procedure at the FMC Sleep Centre, ambulatory sleep test requisitions will be completed by ACPs or physicians, whereas all polysomnogram requisitions will be completed by the primary sleep physician to ensure adequate blinding of patient assignment. The research associate will ensure that all tests are interpreted in advance of clinic visits. Patients who are followed by ACPs in either arm can be referred to the primary sleep physician for assessment of non-respiratory sleep disorders, or for persistent symptoms such as daytime sleepiness.