**4. Acoustic analysis**

This form of evaluation is safe in that there is no radiation involved and it is relatively cheap. It can be performed easily during sleep and at patient's home and simultaneously with polysomnography. Multiple night recordings can be carried out and based on sound frequency spectrum, acoustic analysis can potentially discern simple snoring from OSA.8 Attempts have been made to correlate snoring sound frequency with different levels of obstruction and comparisons of this technique have been made to others such as drug induced sedation endoscopy.9

The sensitivity and specificity of this technique has often been questioned and although it can provide useful screening process, its role in helping with selecting treatment modalities is somewhat limited.10 The other problems in studies with acoustic analysis are that of variation of software and the choice of central or fundamental frequency in determining the site of obstruction.
