obstructive sleep apnoea (OSA)

Introduction

characterized by loud snoring followed by periods of silence when breathing stops or nearly stops which usually occurs at least five times during every hour of sleep
affects 2-4% of adults
snoring associated with sleep apnoea is least likely to occur in stages 3 & 4 (deep sleep) and is most likely in REM sleep
- only when obstructive sleep apnoea becomes very severe and uniform throughout the night will deep non-REM stage 4 sleep be affected because light and REM sleep become so fragmented by apnoeas that the sufferer is not able to reach the point of descent into deep sleep, and it ceases to feature
these apnoeas will splinter REM sleep with awakenings that permit the noisy recovery breaths and so start to erode the normal configuration of sleep staging across the night
where REM alone is affected it can lead the sufferer to be chronically but specifically REM sleep deprived with a consequent propensity to fall into this particular state of sleep during the day otherwise, to fall from wakefulness directly to REM sleep is only normal in young babies
sedatives may aggravate snoring associated with sleep apnoea by depressing the respiratory system, reducing deep non-REM sleep, and increasing light sleep at the expense of REM sleep.

poor sleep causing daytime sleepiness and difficulty concentrating, poor attention span
morning headaches
sore throat upon awakening
may cause polycythaemia due to episodes of hypoxia
increased risk for the development of hypertension, cardiovascular diseases, stroke, diabetes, neurocognitive deficits, depression, and mood disorder
- apneas and hypopneas in REM sleep have been found to be linked with non-dipping of nocturnal blood pressure and incident hypertension whereas unrecognized OSA (ie, patient categorized as no OSA because the overall AHI < 10 events/h, but the AHI in REM sleep ≥ 20 events/h) has an independent association with hypertension
may affect your partner's sleep

clinical polysomnography (PSG):
- apnea-hypopnea index (AHI) = average number of apnea and hypopnea events per night
- complete closure of the upper airway is called apnea, whereas a partial closure is called hypopnea
home monitoring options:
- type 1 incorporates standard PSG
- type 2 uses both sleep stages and respiratory measures with at least seven channels
- type 3 and type 4 use only respiratory measures (at least three respiratory channels in type 3 and at least one respiratory channel in type 4) without any provisions for sleep stages and hence may under-estimate the extent of the more critical REM sleep OSA events
- potential future devices which analyse the sound quality of snoring to ascertain REM vs NREM OSA snores using just audio recordings seem to have >80% accuracy ¹⁾

¹⁾