Parasomnias II
by Helen Driver, Phd, RPsgT

In the last issue, I described parasomnias, “strange things that go bump in the night”, that occur during deep sleep or slow wave sleep (SWS). These parasomnias include sleep walking (somnambulism) and night terrors.  Slow wave sleep is the deepest sleep that normally occurs during the first three hours of sleep, on waking from SWS one may experience confusion and disorientation. Another class of parasomnia that is discussed in this issue are those parasomnias associated with REM sleep.

Parasomnias during REM sleep

            These parasomnias occur during the middle and last third of sleep, when REM periods are more abundant and intense; patients arouse easily and quickly.

Dream anxiety attacks, nightmares

            Dream anxiety attacks or nightmares are frightening dreams with vivid recall.  Often a quick motor reaction in the nightmare is played out which wakes the patient up with a feeling of fear or anxiety. Children who experience nightmares need support and comfort. Environmental factors such as horror films may be important triggers. Dream anxiety attacks typically start during the late teens and correlate with increases in stress, depression, painful life events, insecurity, anxiety and guilt; such attacks are common among patients with post traumatic stress disorder. Other causes include fever, abrupt discontinuation of drugs that suppress REM sleep such as amphetamines, many antidepressants and benzodiazepines (particularly those with short half-lives), and acute alcohol detoxification.  These situations can lead to a rebound in REM sleep, which promotes nightmares.

Sleep paralysis

Sleep paralysis is generally associated with sleep-wake transitions but also occurs from REM sleep. This is a brief period of awakening from sleep being unable to move or speak and may be accompanied by auditory or visual hallucinations.

Impaired or painful penile erections

            Nocturnal erections are a normal component of REM sleep.  Their occurrence can be used to distinguish organic impotence from impotence of a psychological origin.  In rare cases, erections become painful and arouse the sleeper. Treatment with drugs that suppress REM sleep (such as some anti-depressants) may be considered.

REM sleep behaviour disorder

This syndrome, of apparent attempts to enact dreams, is characterized by complex and vigorous motor behaviours during REM sleep usually with dream imagery. REM sleep behaviour disorder may be associated with neurological conditions such as stroke, dementia, multiple sclerosis and severely stressful events. Reported cases are more common in older men (usually presenting at 60-70 years).

Sleep-related cluster headaches

            These are vascular headaches that are associated with REM sleep; the sleeper often wakes up with agonizing pain. These headaches that often have their onset during sleep are categorized as sleep disorders associated with neurologic disorders.

Sleep-related asthma

            Sleep-related asthma is not classified as a parasomnia, rather a sleep disorder associated with a medical disorder, but it is worth mentioning here. Nocturnal asthmatic attacks rarely occur in the first hour of sleep or during SWS. There is a “morning dip” when circadian (around a day) variations and low levels of anti-asthmatic medications exacerbate attacks of asthma.

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