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Fig. 13.1
Dependencies between the Excessive Daytime Sleepiness (EDS) and other factors.
Daytime sleepiness is closely related to the length of sleep and pattern of sleep/awake hours,
and, therefore, cannot be analysed without two additional important factors: duration of sleep
and timing of sleep (circadian rhythm disruption).
purposes and must be interpreted in the context of these purposes; and (4) clinical
concepts evolve over time.
We describe operationalization in more details using as an example of a partic-
ular diagnostic process for obstructive sleep apnea. In our discussion, we use the
generic name obstructive sleep apnea (
OSA
) to indicate Obstructive Sleep Apnea
Syndrome (
OSAS
) and Obstructive Sleep Apnea/Hypopnea Syndrome (
OSAHS
).
OSA
is a common, serious respiratory disorder afflicting, according to conservative
studies, 2
4% of the adult population. The differences in reported
OSA
prevalence
values result from different diagnostic methods and varied definitions of
OSA
.“Ap-
nea” means “without breath,” and
OSA
occurs only during sleep, and is, therefore,
a condition that might go unnoticed for years.
OSA
is caused by collapse of the soft
tissues in the throat as the result of the natural relaxation of muscles during sleep.
The soft tissue blocks the air passage and the sleeping person literally stops breath-
ing (apnea event) or experiences a partial obstruction (hypopnea event). The apnea
event in adult is defined as at least 10 second breathing pause (complete cessation of
air flow) and the hypopnea event is defined as at least 10 second event with reduced
air flow by at least 50%.
Although sleep apnea is not a new condition and has been mentioned sporadi-
cally in literature (e.g., Charles Dickens provided a description of Joe the fat boy), it
was discovered and described only in 1965. Since then, it has been recognized as a
serious respiratory disorder. One of the most important daytime symptoms of
OSA
is excessive daytime sleepiness (EDS). One of the important night symptoms is a
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