PSY3349 Sleep and Sleep Disorders
TASK 4 – BEHAVIORAL PROBLEMS
PARASOMNIAS
Source: Manber (2016)
A parasomnia is an abnormal behavior or perception associated with central nervous system
activation that occurs during sleep or transitions into or out of sleep. There are two broad categories of
parasomnias based on their occurrence during NREM and REM sleep. Useful differentiating factors
between disorders belonging to these REM and NREM parasomnias include the timing of the event,
eyes being open or closed during the event, level of confusion upon awakening and presence or
absences of elaborate dream recall upon being awakened.
NREM parasomnias most often occur during partial arousal from slow wave sleep (N3) and thus are
most likely to occur during the first few hours of sleep. In contrast, REM parasomnias are most
likely to occur during the second half of the night. Unlike REM parasomnias, during NREM
parasomnias the eyes are typically open, and upon being awakened reorientation to place and time is
difficult (individuals feel groggy and confused). Also, unlike REM parasomnias, mental content
during a NREM parasomnia is not elaborate, consisting mostly of a single visual scene.
NREM sleep arousal disorder
NREM sleep arousal disorder is characterized by parasomnias that emerge from stage N3. During the
episode (typically about 20 minutes), the individual is not fully awake (partial arousal). Spontaneous
awakenings from these events are uncommon, and, unless being awakened from the event, next
morning amnesia for the episode is common. When awakened from an event, the individual usually
reports negatively valenced emotions (e.g., fear) associated with the experienced mentation. The
DSM-5 includes two specifiers for this disorder; sleep walking type and sleep terror type.
A sleep terror most often starts with a scared or panicky scream. The individual experiencing the event
may abruptly sit up in bed in a state of high autonomic arousal (e.g. pupil dilation, perspiration, rapid
heart rate and respiration). The individual experiencing the sleep terror often has little to no recall of
the event the next morning. Most individuals with night terrors report that it occurs in a context of a
dream-like situation, typically an unpleasant scene, but there is no report of an elaborate narrative.
Adults with NREM sleep arousal disorder report being sound sleepers and difficult to arouse.
Consistent with their self-report, they spend more time in stage N3 (the deepest stage and most
difficult to arouse from), which also explains the tendency to become only partially awake during the
event. The events do not occur nightly and are therefore difficult to capture on a single-night PSG, but
NREM parasomnias are more likely when a patient is sleep-derived.
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, PSY3349 Sleep and Sleep Disorders
It is recommended that observers avoid waking the sleeper during NREM parasomnia events because
wakening from N3 is often associated with unnecessary confused arousal. Instead, sleep walkers can
be gently oriented back to bed.
Considerations for differential diagnoses for sleep walking include REM-sleep behavior disorder,
which is discussed later. Considerations for differential diagnoses of sleep terror include
distinguishing between a sleep terror event and nightmares, nocturnal seizures, and nocturnal panic
attacks.
Nightmare disorder
Nightmare disorder is one of two REM sleep arousal disorders. A nightmare is a vivid, intensely
frightening, and well-remembered dream from which a sleeper wakes up independently and
quickly becomes oriented. Under normal conditions, body movements and vocalizations during the
nightmare are rare due to the normal loss of muscle tone during REM sleep. Nightmares are most
likely to be experienced during the second half of the night, when REM sleep is more likely to take
place. Although nightmares may be experienced frequently, their content is typically not repeated,
although themes of nightmares (such as an escape theme) can often be identified. However,
nightmares associated with a traumatic event do tend to have replicative or repeated dream content
PSG reveals that the sleep of individuals with frequent nightmares is mildly disturbed (reduced
efficiency and longer sleep latency) and contains less slow wave sleep. Nightmares can occur in the
course of normal healthy sleep. A diagnosis of nightmare disorder may be warranted when the
nightmares occur repeatedly and when there is high distress about having a nightmare (e.g.,
apprehension about going to sleep to avoid the unpleasant experience) or impairment in functioning
related to the nightmares.
The most salient factor distinguishing between nocturnal panic and nightmares is that the former is
not associated with dream content. Like nightmares, sleep paralysis is experienced as an awakening
associated with intense fear and sometimes includes frightening imagery. However, unlike nightmares,
the individual experiencing sleep paralysis is aware of being fully awake when experiencing the
frightful imagery and paralysis
REM sleep behavior disorder
REM sleep behavior disorder (RSBD) is characterized by dream enactment during sleep. These
events occur because of intermittent loss of muscle atonia normally present during REM. During the
events, individuals engage in complex behavioral consequences that often cause harm to the individual
or another person (bed partner). If woken during the event, individuals quickly become oriented and
report dreams corresponding to their behavior. Dream enactment mostly occurs the latter half of the
night.
The majority of patients experiencing RSBD develop one of a range of neurodegenerative diseases
within a decade. Parkinson’s disease and multiple system atrophy are most common. RSBD symptoms
can also occur with some medications that affect REM sleep, such as selective serotonin reuptake
inhibitors
When a diagnosis of RSBD is being considered, an overnight laboratory sleep is typically conducted
utilizing video recording throughout the night. These studies do not always capture an event because
the events may not occur nightly. Because RSBD is common in narcolepsy, an MSLT is routinely
administered after the overnight sleep study.
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