Obstructive Sleep Apnoea

Symptoms of OSA

Snoring

Snoring occurs in virtually all OSA subjects and characteristically is loud (> 44 dB) and intermittent, graphically illustrating the fact that noise is created principally between apnoeas, when large tidal volumes are drawn through an airway that has just achieved patency (Brown, 1994).

Choking

Some patients awake with the feeling of choking or gagging. This is due to the increasing level of airway obstruction they are experiencing during the apnoeic cycle.

Abnormal motor activity

Subjects with OSA are experiencing asphyxiation during sleep due to upper airway obstruction and their sleeping behaviour reflects this. They may complain of restlessness, which may be manifest by increased tossing and involuntary movements during sleep.

Nocturia

The proposed mechanisms for this include: increased intra-abdominal pressure associated with the respiratory efforts against a closed upper airway; an alteration in the various humoral agents induced by hypoxaemia and more controversially, raised levels of atrial natriuretic factor (Roux et al., 2000).

Daytime sleepiness

Excessive daytime sleepiness (EDS) in SBD can result from hypoxia and a poor quality of sleep due to multiple arousals, that terminate most of the respiratory events, leading to sleep fragmentation (Sink et al., 1986; Colt, 1991). The aetiology of EDS remains controversial, however Colt (1991) using a prospective randomised crossover study provided the strongest evidence relating EDS to sleep fragmentation rather than hypoxia. EDS can result in the sufferer falling asleep at unexpected and inappropriate moments. In extreme cases, this can be while talking or eating, with the subject managing to stay alert only if moving or being constantly stimulated. Adverse effects of EDS also include reduction in overall performance, inability to concentrate, poor memory and temporal disorientation (Kaplan, 1992; Jennum and Sjol, 1994). This can have a profound effect on the safety of both the individual and others if, for example they operate machinery or drive vehicles for an occupation. Research demonstrates that drivers suffering from pathological sleepiness were up to seven times more likely to be implicated in an accident than unaffected individuals (Haraldsson et al., 1990) and perform poorly under simulated driving conditions (Juniper et al., 2000). Sufferers may therefore find themselves unemployed, either because they feel unable to cope with their work or because they are required to give it up in case they become a danger to others.

Depression and psychological dysfunction

There is increasing recognition of a link between OSA and depression. Sleep changes, most notably disturbances of REM sleep, are intrinsic to depressive disorders (Kaplan, 1992). Relief of mild to moderate sleep- and breathing-related disorders in children is associated with improved behaviour and psychological functioning (Ali et al., 1994).

Sexual problems

Abatement of sexual drive or impotence have been reported in patients with OSA (Karacan and Karatas, 1995). However, this may be a reflection of the age of the cohort rather than SBD (Schiavi et al., 1991).

Headaches

Morning headaches and headaches that are so severe they awaken the sufferer during the night are often reported in people with OSA. The former have been reported to be three times more common in subjects with SBD, than in the general population (Ulfberg et al., 1996). They are thought to be vascular in origin but their precise mechanism remains disputed.