Scientific research has taught us that snorers snore on average louder and more frequently in the supine compared to the lateral position. This is old news for the partner of a snorer. Then why is it not possible to prevent snorers from sleeping on their backs? Indeed, preventing sleeping in the supine position can be effective for many positional snorers. The classic approach is the so-called tennis ball method: the snorer has to wear a shirt with a tennis ball attached to the back during the night. If the person turns on his or her back during the subconscious state of sleep, the tennis ball will give an uncomfortable feeling and the person will ideally turn from the supine back to a lateral position. Unfortunately, tennis balls are generally poorly tolerated, often lead to sleep disturbances, and there are snorers who will still sleep in a supine position despite the ball on their back.
In 1985 Rosalind Cartwright and her coworker Stephen Lloyd created the first chest-worn sleep position apparatus. They were also the first to describe the observation of a training effect with such an apparatus. Some users learned not to sleep supine even without the apparatus after using it for a while.
Snore Trainer is an app that runs on the iPhone and iPod. The iDevice is typically worn on the chest during sleep. Snore Trainer has been created for positional snoring, and not for patients with obstructive sleep apnea.