Article
Frequency analysis of snoring sounds under simulated snoring and nocturnal snoring
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Published: | August 8, 2007 |
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Outline
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Background: The topodiagnosis of snoring sounds is still a difficult task in somnology. Aim of the study was to compare snoring sounds during simulated snoring under wake conditions with nocturnal snoring by frequency analysis and to evaluate the significance with respect to the topodiagnosis of snoring.
Method: 50 male patients with a history of snoring were examined prior to night time polysomnography (PSG) by flexible endonasal endoscopy. The patient was asked to simulate snoring and the produced snoring sounds were recorded. Additionally, snoring sounds were recorded during PSG. Nocturnal snoring sounds were divided into rhythmical and non-rhythmical sounds according to their occurrence in combination with obstructive apneas. The snoring sounds were analysed and compared according to the present peak intensities (PI) 1 – 5 of the frequency response curve.
Results: The PIs 1-3 under simulated snoring were present between 100 and 300Hz. PIs 4 and 5 got at 1500Hz. Similar PI were detected for nocturnal rhythmical snoring episodes. Non-rhythmical nocturnal snoring episodes showed divergent frequency spectra between 2000 and 3000Hz for all PIs.
Conclusion: Simulated snoring episodes have similar frequency spectra as rhythmical nocturnal snoring. Non-rhythmical snoring differs from simulated and rhythmical nocturnal snoring. Rhythmical snoring can be imitated by the patient by simulated snoring and can be observed by flexible endoscopy under wake conditions. Snoring in combination with obstructive events can not be simulated awake. Simulated snoring and flexible endoscopy might help to localize snoring sounds and provide additional information for a potential surgical therapy.