Sleep studies measure leg movements, jaw activity, EEG, EKG, chest and trunk motion. A description/outline of these categories and what they indicate would be interesting and helpful. All contributors or causes of OSA would be helpful. Describe central apnea causes/contributors. Can a person change ongoing apnea by improving circulation? Exercise? Exercise with oxygen? Changing neck/head position? Light? It would seem that it can be improved by something other than supplemental oxygen or weight loss.