Comparing perceptions and measurements of snoring

The difficulty in measuring and quantifying snoring using objective criteria is that snoring is first and foremost of a subjective perception by a listener. To test the subjective perception of snoring and to compare it with objective measurements, we studied 25 patients referred to our laboratory because of snoring. All had full nocturnal polysomnography including measurements of snoring. Snoring sounds were recorded on paper and simultaneously stored on audiotape. The technologist scoring the polysomnogram counted the number of snores during a 20-minute segment. Two other technologists, unaware of the objective snoring count, listened to the audiotape and also counted the number of events that they perceived as snores. In 11 of 25 patients there was good agreement (within 25%) between the two listeners and the objective snore count. In another 7 of 25 patients there was good agreement between the listeners, but the objective snore count differed > 25%. In the last group of seven of 25 patients the difference in subjective snore counts perceived by both listeners was > 25%. The agreement between both listeners in judging snoring severity was moderate (weighted Cohen's kappa (w) = 0.49). We conclude that perception of snoring is highly subjective. We speculate that investigations studying consequences and treatment of snoring must employ either more sophisticated properly validated methods to measure snoring or alternatively resort to measurements of the underlying physiological abnormalities responsible for snoring, such as elevations in upper airway resistance.