The term ‘chronic insomnia’ applies when sleep-wake disorders occur at least three times a week and are accompanied by demonstrable problems – fatigue, sleepiness, concentration issues and irritable behaviour – during the day for at least three months in a row. Kempenhaeghe itemizes sleep-wake disorders based on the complaints the patient lists:
Bad sleep at night
Bad sleep often relates to problems getting to sleep and staying asleep; and premature awakening. Pondering, stress, anxiety - and possibly a depression – can thwart healthy sleep. Also bad sleeping habits can lead to sleep issues. Furthermore physical complaints may exist, e.g. a breathing disorder during sleep (sleep apnea) or restless legs syndrome.
Increased sleepiness by day
Some people experience increased sleepiness and fatigue by day. A small group even falls asleep at random moments. They are unable to resist this. These people may suffer from a rare condition (narcolepsy) or may be that overtired as a result of a breathing disorder during sleep (sleep apnea) or restless legs syndrome. Sometimes an irregular lifestyle or use of medication causes the increased sleepiness.
Disruption of the sleep-wake rhythm
At the underside of the brain the biological clock that regulates the sleep-wake rhythm is located. That clock is calibrated differently for every person. This regulatory centre in the brain responds to changes in the intensity of environmental light as perceived by the eyes. These changes influence the time at which one falls asleep and wakes up. The biological clock can be thrown off by a.o. sleeping late, a ‘jet-lag’ or working in shifts. For some people their biological clock deviates naturally from the social rhythm (office and school hours). This can seriously impede their normal functioning.
Undesirable behaviors at night
Sleep-walking, anxiety attacks, bedwetting, gnashing of the teeth and restless behavior during dream sleep are examples of what is called “undesirable behaviors at night”. These mostly ‘innocent’ symptoms mainly occur in children, but sometimes also in adults. An estimated portion of five to seven percent of the Dutch population suffers from a chronic sleep-wake disorder. Treatment by a general practitioner or medical specialist is effective for most of them. Because of the sometimes high complexity of the disorder, diagnosis and/or treatment in an expertise centre for sleep-wake disorders may be required. Kempenhaeghe is such an expertise centre.