The gold-standard for diagnosing sleep apnea is a sleep study also known as a polysomnography. This is an overnight study that is ordered by a physician. The sleep study will determine if you have sleep apnea, what type of sleep apnea (central or obstructive), and the severity of the sleep apnea. Mild and moderate obstructive sleep apnea can be treated with oral appliances. Severe sleep apnea should be treated with a CPAP device.
In my office, every new patient completes an Epworth Sleepiness Scale as part of our new patient exam. If a patient scores above a 10 on this study then I recommend that they have their physician order an overnight sleep study.