Analysed snoring sounds correlate to obstructive sleep disordered breathing

Snoring occurs as a major symptom in patients with sleep disordered breathing (SDB). The aetiology of snoring remains still unclear despite various attempts to localize snoring. The correlation between different snoring sounds and the severity of SDB has not yet been investigated in a larger population. The aim of this study was to record and analyse snoring sounds and to correlate the obtained data with clinical and polysomnographical parameters. Sixty male patients with suspected SDB and reported snoring underwent a clinical examination and night time polysomnography. The parallel digitally recorded snoring sounds were analysed by fast fourier transformation (FFT). Peak intensity was determined from the power spectrum. The periodicity of snoring was classified into rhythmic and non-rhythmic snoring according to the presence of air flow interruptions due to obstructive apneas. Patients with primary snoring revealed peak intensities between 100 and 300 Hz. Patients with an obstructive sleep apnea syndrome (OSAS) revealed peak intensities above 1,000 Hz. Polysomnographical data (AHI, mean and minimum SpO₂) as well as body mass index (BMI) correlated with peak intensity of the power spectrum. None of the parameters of the clinical examination correlated with peak intensity. Frequency analysis of snoring sounds provides a useful diagnostic tool to distinguish between different patterns of snoring and respective SDB. The topodiagnosis of snoring is not possible by means of frequency analysis or clinical examination alone. Acoustical analysis of snoring sounds seems a promising additional diagnostic tool to verify different types of SDB in snoring patients.