Anyone who shares a bed with a snorer will know how annoying the nasal noise can be. It’s a point of contention among roommates, campers and in marriages the world over. However, snoring is often accompanied by a much more sinister problem – obstructive sleep apnea (OSA), in which the upper airways can collapse during sleep. It is a known cause of tiredness among snorers but can also lead to high blood pressure and other serious health issues.
Now, researchers in Australia and Japan have used noise analysis to test audio recordings of 5,568 episodes of snoring to reveal that not only is the snoring sound complicated but it seems to follow a non-linear mathematical pattern, which is different from the linear sound pattern researchers had assumed it to follow previously. The discovery might one day help in monitoring chronic snoring to help diagnose the more serious problem of OSA.
Takahiro Emoto of the Institute of Technology and Science, at The University of Tokushima, and colleagues there and at The University of Queensland, in Brisbane, explain that while not everyone who snores suffers from OSA almost everyone with OSA snores. This means that the presence of snoring has not been considered a reliable indicator of OSA. A method of easily diagnosing the condition has, therefore, remained elusive.
Writing in the International Journal of Medical Engineering and Informatics, the team describes an approach to analyzing the sound of snoring that can reveal characteristic audio patterns that, in their preliminary investigation seem to correlate with a likely diagnosis of OSA. These patterns are entirely absent in the snoring of people without OSA. The team has carried out early tests of their analytical approach to snoring on a small group of just 27 volunteers, which suggests they might be able to reveal which snorers also suffer from OSA on the basis of this sound analysis. More work needs to be done before such a test can be validated for clinical use.
Takahiro Emoto, Udantha R. Abeyratne, Masatake Akutagawa, Yohsuke Kinouchi, & Shinsuke Konaka (2011). Testing the system non-linearity in snoring sound via neural networks Int. J. Medical Engineering and Informatics, 3 (3), 299-310.