Obstructive sleep apnea is a condition that causes throat muscles to relax and narrows the airways of those affected while they are asleep. Snorting, choking or gasping while sleeping are the indicators of the condition. Usually the sufferers' partner notices before they do!

People with mild to moderate sleep apnea experience daily fatigue and a shortened attention span from lack of sleep. Sleep apnea can also have more serious consequences; people have died from very severe forms of the condition.

"Your eyes are closed but you're not resting," explains Dr. Cynthia Concepción-Medina, Research Assistant at the Department of Orthodontics at Hiroshima University Hospital who contributed to the study with her colleagues Associate Professor Hiroshi Ueda and Dr. Yu Matsumura.