An acoustic screening test for obstructive sleep apnoea.

Third-octave sound analysis was performed on the snoring sounds of nine subjects with obstructive sleep apnoea (OSA) and 18 with simple snoring. Both groups demonstrated a large low frequency peak in linear sound levels at around 80 Hz. However, the OSA group displayed a substantially larger high frequency sound component. We utilized this fact in the development of an acoustic index (Hawke Index: HI) which describes the ratio between the overall A-weighted and linear sound levels for the recorded snoring sound of each subject [HI = dB(A)/dB(SPL) for Lmax]. There was a significant positive correlation between the apnoea/hypopnoea index and the HI (r = 0.73, t = 5.3, 25df, P < 0.001). If a value of 0.90 or greater was taken as diagnostic of OSA, the HI exhibited 67% sensitivity, 100% specificity, 100% positive and 86% negative predictive accuracy. With further development, we believe this acoustic phenomena may have a role as a screening test in the diagnosis of OSA.