Is acoustic analysis of snoring an alternative to sleep nasendoscopy?

Abstract

Previous studies have suggested that acoustic analysis may be useful in distinguishing different types of snoring prior to possible corrective surgery. This study aimed to establish whether it could replace sleep nasendoscopy in a clinical setting. Thirty-five patients undergoing sleep nasendoscopy had their snoring recorded and analysed using commercially available equipment. It was found that centre frequency can be used to distinguish pure palatal from tongue base snoring, with a clear cut-off value of 90 Hz between the two. Multisegmental snoring cannot be identified on the basis of centre frequency alone. It may be distinguished from tongue base, but not palatal snoring by the nature of the frequency distribution plot (sensitivity 77%, specificity 81%). Blinded assessment of waveforms of individual snores gave poor accuracy (53%) and poor interobserver agreement (kappa = 0.10). Acoustic analysis may help screen for pure tongue base snoring. However, we feel that it is unlikely to replace sleep nasendoscopy.

Evaluation of acoustic characteristics of snoring sounds obtained during drug-induced sleep endoscopy

“…Thereby, a possible differentiation between palatal and non-palatal snoring is frequently reported. Contrary to that, other sites of obstruction can hardly be detected by acoustic analyses [4,1,7,[22][23][24][25].…”

“…In recent years, various publications differentiate specific snoring types and anatomic structures that may create specific snoring sounds. Tongue base snoring is reported to have predominant frequency patterns above 500 Hz and palatinal snoring below 500 Hz [3,4,1,2,[5][6][7][8]. Most data are based on the visualisation of vibrating structures during sleep endoscopy.…”

“…Whilst palatinal snoring is reported to have a main frequency below 500 Hz, the one found for tongue base snoring is above 500 Hz. Snoring episodes terminating obstructive apnoeas can exceed frequency maxima up to 4000 Hz [1][2][3][4][5][6][7][8]. Nevertheless, the data vary extremely depending on the method of recording and the parameters analysed.…”

Acoustical flow estimation in patients with obstructive sleep apnea during Sleep

“…However, the high cost of PSG and the high prevalence of OSA in the general population have persuaded researchers to look for portable monitoring devices, such as acoustic techniques, for sleep apnea monitoring [5,6,[19][20][21][22]. However, the previous studies on flow-sound relationship were all focused on data of awake non-OSA individuals.…”

Evaluation of upper airway obstruction in snoring patients using digital video stroboscopy

“…Previous studies, including those by the senior author, have described the use of acoustic analysis to predict the site of upper airway obstruction in snoring patients. For example, Saunders et al [4] identified that palatal snorers produced sound with a centre frequency below 90 Hz, whereas all pure tongue-base snorers produced sound with a centre frequency above this value, thereby allowing one to differentiate between the two snoring causes and decide on a more appropriate treatment strategy in each instance. Further investigations have concurred with this idea and claimed that it should indeed be possible to use sound spectral analysis to determine anatomically obstructive areas [5][6][7].…”