Can Snoring Wake Up the Snorer? The Effects of Snoring on Sleep Quality

What happens to the snorer when he snores? This is an intriguing question. It is said that snoring is associated with adverse health outcomes including excessive daytime sleepiness and cardiovascular disease. This is because snoring is a biomarker for underlying obstructive sleep apnoea (OSA) and the latter can lead to various dangerous complications. There are actually some theories which suggest that snoring sounds may have an effect on sleep or health of the snorer. This is because during sleep, the reticular nucleus of the thalamus plays a gating function that is believed to screen from cortical perception much of the sensory information that would otherwise pass unhindered during wakefulness. While particularly loud sounds or those with significance can lead to awakening, internally generated, monotonous, and recurrent snoring sounds are habituating, ignored by the brain, and incapable of arousing the sleeper.

Thus a recent study began to take note of the sleep of patients, at risk for OSA, with and without use of earplugs. Earplugs could decrease snoring sound perception through aural air conduction, or potentially increase it through bone conduction in the absence of external “white noise”, but a critical advantage of earplugs is that any change in sleep and breathing when they are used can be attributed more readily to a change in sound perception than to a change in the patency of the upper airway. The researchers then used an electronic algorithm that we developed previously to demonstrate and quantify cortical arousal that occurs on a breath-to-breath basis during sleep, outside time occupied by apnoeas or hypopneas.

This randomised controlled trial determined whether snoring sounds could create these microarousals, and investigated whether earplugs, anticipated to alter snoring perception, might affect respiratory cycle-related electroencephalographic (EEG) changes. This study was done at an accredited, academic sleep laboratory utilising 400 adults referred for suspected obstructive sleep apnoea. The subjects were then randomly assigned to use earplugs or not during a night of diagnostic polysomnography.

The results showed that earplug use was associated with lower respiratory cycle-related electroencephalographic (EEG) in delta EEG frequencies (0.5-4.5 Hz), although not in other frequencies, after controlling for potential confounds (P = 0.048). This effect of earplug use was larger among men in comparison with women (interaction term P = 0.046), and possibly among non-obese subjects in comparison with obese subjects (P = 0.081). However, the effect of earplug use on delta respiratory cycle-related electroencephalographic (EEG) did not differ significantly based on apnoea severity or snoring prominence as rated by sleep technologists (P > 0.10 for each).

Thus the study concluded that perception of snoring sounds, as modulated by earplugs, can influence the cortical EEG during sleep. Snoring sounds made during sleep have the capability of waking up the patient with sleep apnoea. More studies are actually needed to tell whether snoring has an effect on the sleep quality of snorers.

Reference:

Chirakalwasan N; Ruzicka DL; Burns JW; Chervin RD. Do snoring sounds arouse the snorer? SLEEP 2013;36(4):565-571.

Image  Courtesy of graur codrin / freedigitalphotos.net