Snoring without OSA and health consequences: the jury is still out

Detection of Snores Using Source Separation on an Emfit Signal

Snoring (SN) is an early sign of upper airway dysfunction, and it is strongly associated with obstructive sleep apnea. SN detection is important to monitor SN objectively and to improve the diagnostic sensitivity of sleep-disordered breathing. In this study, an automatic snore detection method using an electromechanical film transducer (Emfit) signal is presented. Representative polysomnographs of normal breathing and SN periods from 30 subjects were selected. Individual SN events were identified using source separation applying nonnegative matrix factorization deconvolution. The algorithm was evaluated using manual annotation of the polysomnographic recordings. According to our results, the sensitivity, and the positive predictive value of the developed method to reveal snoring from the Emfit signal were 82.81% and 86.29%, respectively. Compared to other approaches, our method adapts to the individual spectral snoring profile of the subject rather than matching a particular spectral profile, estimates the snoring intensity, and obtains the specific spectral profile of the snores in the epoch. Additionally, no training is necessary. This study suggests that it is possible to detect individual SN events with Emfit mattress, which can be used as a contactless alternative to more conventional methods such as piezo-snore sensors or microphones.

Self-reported obstructive sleep apnea, simple snoring, and various markers of sleep-disordered breathing as predictors of cardiovascular risk

PURPOSE

Our objective was to investigate whether self-reported obstructive sleep apnea (OSA), simple snoring, and various markers of sleep-disordered breathing (SDB) are associated with cardiovascular risk.

METHODS

We examined a representative nationwide cohort of 5177 Finnish adults aged ≥30 years. The participants underwent measurement of traditional cardiovascular risk factors and answered SDB-related questions derived from the Basic Nordic Sleep Questionnaire, which were used to operationalize self-reported OSA. The primary end point was incidence of a cardiovascular event (cardiovascular mortality, non-fatal myocardial infarction, non-fatal stroke, hospitalization for heart failure, or coronary interventions).

RESULTS

During a median follow-up of 11.2 years and 52,910 person-years of follow-up, 634 participants suffered a cardiovascular event. In multivariable-adjusted Cox models, self-reported OSA (hazard ratio [HR] 1.34; 95 % confidence interval [CI] 1.04-1.73; p = 0.03) was an independent predictor of cardiovascular events. Self-reported simple snoring by itself was not associated with future cardiovascular events (HR 0.88 versus non-snorers, 95 % CI 0.75-1.04, p = 0.15). However, among snorers (n = 3152), frequent breathing cessations (HR 2.19, 95 % CI 1.26-3.81, p = 0.006) and very loud and irregular snoring (HR 1.82, 95 % CI 1.31-2.54, p < 0.001) were associated with cardiovascular risk.

CONCLUSIONS

Self-reported OSA and SDB-related snoring variables are associated with cardiovascular risk, whereas simple snoring is not. In clinical practice and in surveys, questions concerning only habitual snoring should be amended with questions focusing on respiratory pauses and snoring stertorousness, which can be used to estimate the risk of OSA and cardiovascular events.

Nasal steroids in snorers can decrease snoring frequency: a randomized placebo-controlled crossover trial

Although it is anecdotally known that nasal obstruction is associated with snoring, it remains unknown whether the application of nasal steroids could decrease oral/oro-nasal breathing and increase nasal breathing, and subsequently decrease snoring indices. This study evaluated the effect of nasal budesonide on breathing route pattern and snoring. Twenty-four snorers were enrolled in a randomized, double-blind, crossover trial of 1-week treatment with nasal budesonide compared with 1-week intervention with nasal placebo. At the start and end of each treatment period, patients underwent nasal resistance measurement and overnight polysomnography with concomitant measurement of breathing route pattern and snoring. Twelve patients were randomly assigned to a 1-week treatment with nasal budesonide, followed by 2-week washout period and a 1-week intervention with the nasal placebo; and 12 patients were randomly assigned to a 1-week intervention with nasal placebo, followed by 2-week washout period and a 1-week treatment with nasal budesonide. Nasal budesonide was associated with a decrease in oral/oro-nasal breathing epochs and concomitant increase in nasal breathing epochs, decrease of snoring frequency by [median (interquartile range)] 15.8% (11.2-18.8%), and an increase of rapid eye movement sleep; snoring intensity decreased only in patients with increased baseline nasal resistance by 10.6% (6.8-14.3%). The change in nasal breathing epochs was inversely related to the change in snoring frequency (Rs = 0.503; P < 0.001). Nasal budesonide in snorers can increase nasal breathing epochs, modestly decrease snoring frequency and increase rapid eye movement sleep.