Answer: chuck,depends on whether apnea is central,or peripheral,,,,in case of central..this refers to an electrical malfunction where the necessary impulses to sustain respiration during sleep do not get sent out,,,,,,,,a previous episode of encephalitis,or meningitis,,,sometimes a simple cold & flu episode which causes nerve damage to brain tissue,,,,,,,,like at a burned building where the cause of the fire is at the boiler area,,,,,,,,,peripheral applies to the intercostal or rib muscles,the diaphragm.throat,larynx,,,,,,,... malfunction in terms of their shape,or not responding to messages sent by the brain.the throat might tend to collapse periodically during sleep because of loss of muscle tone temporarily,,,,,,,,this is periodic obstructive apnea.,,,,,,,the apparatus the other guy describes is meant to kick on operation when breathing muscles cease for 15 or 20 swconds,,,,,,,it automatically inflates the lungs with oxygen,,,,,,the antidepressant meds serve to add a bit of stimulation to the brain,sending otherwise absent impulses to their destination to your "breathing apparatus",,,,,for some people there is no relief with the above measures,,,,,,,fungal illness can mimic to the letter,the symptom/complaints of the patient,but show no results during the wiredup sleepstudy sessions at the clinic,,,,,the patient is sick,profoundly tired,and is sent packing because the needle don't go nowhere,doesen't make marks on the graph paper,,,,,,,,,systemic antifungals sometimes help these folks.......they could have food allergies that aggravate the sleep problem,,,,,,,and avoid chemical exposure for a few weeks or months