Night noise guidelines for Europe - WHO/Europe - World Health ...

SLEEP AND HEALTH 19
• daytime sleepiness
• motivation, energy, or initiative reduction
• proneness to errors or accidents at work or while driving
• tension, headaches, or gastrointestinal symptoms in response to sleep loss
• concerns or worries about sleep.
Defining the cause of a sleep/wake disturbance in an insomnia patient is a complex
task since it is often multifactorial. In fact, a confluence of factors that support multiple
insomnia diagnoses may be judged important in many patients with insomnia.
Although selection of a single diagnosis is preferable and this selection may be
appropriate, such a selection should not necessarily imply the absence of a subset of
factors relevant to an alternate diagnosis. When criteria for multiple insomnia diagnosis
are met, all relevant diagnosis should be assigned.
2.1.2.3 Environmental sleep disorder
In the ICSD 2005, environmental sleep disorder is listed in the category of “other sleep
disorders”. Noise-induced sleep disturbance is one of the disturbing environmental factors
that cause a complaint of either insomnia or daytime fatigue and somnolence.
The diagnostic criteria for environmental sleep disorder are the following.
A. The patient complains of insomnia, daytime fatigue or a parasomnia. In cases
where daytime fatigue is present, the daytime fatigue may occur as a result of
the accompanying insomnia or as a result of poor quality of nocturnal sleep.
B. The complaint is temporally associated with the introduction of a physically
measurable stimulus or environmental circumstance that disturbs sleep.
C. It is the physical properties, rather than the psychological meaning of the environmental
factor, that accounts for the complaint.
D. The sleep disturbance is not better explained by another sleep disorder, medical or
neurological disorder, mental disorder, medication use or substance use disorder.
The prevalence of environmental sleep disorder is not known. Fewer than 5% of
patients seen at sleep disorder centres receive this diagnosis.
International standardization and quantification for measurement of the depth of sleep is
based on Rechtschaffen and Kales criteria from 1968. Sleep is divided into 30-second
epochs, and a phase is only assessed if the specific features are evident for more than 50%
of the epoch length. For example, wakefulness is scored when at least 15 seconds of continuous
awakening is present. Arousal reactions not leading to macroscopic awakening
were not included in the definition by Rechtschaffen and Kales. With the arousals as
described by the American Sleep Disorders Association (1992) it is possible to display subvigilant
sleep fragmentation, caused by intrinsic sensory and autonomic alarm reactions.
An arousal index providing the arousal density (events per hour of sleep) was taken as a
measure of the degree of severity. In one hour, 10–20 arousals are considered as normal in
healthy adults. However, the use of EEG arousals with the American Sleep Disorders
Association definition provides no sufficient explanation of daytime sleepiness (Ali, Pitson
and Stradling 1996; Ayas et al., 2001) unless they are accompanied by vegetative arousals.
Regarding noise, different vigilance level assessments in various functional systems are
important. Dumont, Montplaisir and Infante-Rivard (1988) proposed investigations of
NIGHT NOISE GUIDELINES FOR EUROPE