Changes in snoring during natural sleep identified by acoustic crest factor analysis at different times of night

Sleep nasendoscopy can be used to identify the site of snoring but question s remain about how well a short assessment during drug-induced sleep reflec ts the natural condition. To investigate the uniformity of snoring during n atural sleep we studied five patients (three men, two women) referred by th eir GPs for treatment of their snoring. A digital audio tape recorder captu red the free-field snore sound at different times of night in hospital. Aco ustic Crest Factor values were calculated on the 15 recordings made, having previously demonstrated that high crest factor values distinguish palatal from non-palatal snoring at sleep nasendoscopy. Some recordings showed repr oducibility, but others showed substantial changes between recordings an ho ur apart. We infer that the snoring mechanism may change in some individual s during the night, with or without a change of snore site. We conclude a s ingle recording, as in sleep nasendoscopy, may not be representative.