Task 6: Behavioral problems?
What are parasomnias?
Phylogeny, ontogeny and pathophysiology
REM and NREM sleep develop from undifferentiated pre-sleep activity in utero. With progressive
maturation, independent oscillations of neuronal activity, autonomic function and overt behavior
become organized into distinct sleep stages like REM and NREM sleep (also called active and quiet
sleep-in newborns).
At 29 weeks post-conception about 20% is transitional (indeterminate sleep) that shows
intermingling of elements of active and quiet sleep.
o With progressive cortical maturation over the next few weeks, indeterminate sleep
seems to resolve.
Another important feature of newborn sleep is the presence of non-epileptic, stereotyped motor
patterns, like bicycling moving during sleep.
o Are a result of the immature cortical neuronal network (incomplete myelination of the
descending motor projection systems), combined with an immature cerebellar system.
Parasomnias are the consequence of dissociation between wakefulness, NREM or REM sleep with
behaviors characteristic of one state becoming superimposed on another.
Generation of non-epileptic stereotyped movements at subcortical levels is related to activation
of networks of interneuron = central pattern generators (CPGs), which in turn recruit motor
neurons in the ventral brainstem or spinal cord as the final, effector step in the elicitation of
stereotypic movements.
o CPG in pons/medulla -> mastication,
o CPG in spinal cord -> walking
o CPGs can be activated by glutaminergic and serotonergic inputs
NMDA receptor antagonists suppress activity of spinal CPGs
Descending serotonergic projections from the raphe nucleus to the spinal cord
also play a complex role in modulating spontaneous and synchronous rhythmic
activities generated at the spinal level.
o Genetic factors and underlying sleep disorders may activate spinal or brainstem CPGs ->
based upon the nature of the CPG that has been activated, one may observe
sleepwalking, rhythmic movement disorder, head banging, bruxism, or other stereotyped
behaviors in sleep.
Arousals = adaptive responses of the sleep regulatory system -> exhibit diverse EEG patterns
o They are also reflected in the phase A subtypes of cyclic alternating patterns (CAPs).
CAPs = ultra-slow EEG oscillations in NREM (20-40s periodicity) that organize sleep
dynamically.
CAPs can trigger stereotypic events in sleep, like epileptic seizures to nocturnal
myoclonus, bruxism and sleepwalking.
What provokes parasomnias in childhood:
Synaptic pruning around 8 months in visual cortex and by 24 months in frontal cortex ->
removal of excess of excitatory and inhibitory synapses.
o Also occurs in the cerebellum and brainstem -> in the cerebellum, the activation of the
NMDA glutamate receptor is involved.
o Concurrently, a process of programmed cell death is also initiated in the CNS
Down-regulation of descending GABAergic projections from the cerebral cortex to the brainstem
or diminished serotonergic inhibition of the spinal cord may play a key role in the pathogenesis
of sleep-wake transition parasomnias and the arousal parasomnias. These changes may also
impact the regulation of CAPs.
o Around age 2, a combination of genetic predisposition to sleep state dissociation,
completion of myelination of the pyramidal tracts and maturation of the cerebellar
system, combined with reflex activation of subcortical central pattern generators triggers
certain stereotypic patterns of behavior
At sleep onset, these patterns may manifest as hypnic starts, sleep paralysis or
rhythmic movements, while during sleep they manifest as confusional arousals,
sleep terrors or sleepwalking
, oThis hypothesis is further supported by the prompt resolution of most parasomnias upon
treatment with GABAergic agents like the benzodiazepines
Explains why parasomnias the period from birth-18 months = silent period for parasomnias ->
overt expression is minimal.
o Parasomnias overtly manifest in pre-school age children and resolve by the latter half of
the first decade (concurrent with progressive maturation of subcortical inhibitory
projection systems), only to reappear in some adults.
Epidemiology
Study general population: 45% of children aged 4-16 years have experienced sleepwalking, but
only 2-3% had at least one episode per month.
o Frightened awakenings from sleep in about 40% and 3.5% met criteria for sleep terrors
Study childhood parasomnias: 14.5% sleepwalking, 39.8% sleep terrors, 25% sleep enuresis,
45.6% bruxism, 9.2% rhythmic movements
o Occurrence of parasomnias in pre-school aged children is quite ubiquitous -> children
frequently experience minor episodes of partial awakening from sleep
o 88% in study cohort manifested at least one parasomnia during the study period
What are the different types of parasomnias?
Sleep-wake transition parasomnias
Hypnic starts
Also termed sleep starts = isolated, quick jerks of the upper or lower extremities at sleep onset. They
might be accompanied by a sensation of falling, a dream-like feeling or a flashing sensation.
They are benign, occurring in approximately 70% of people of all ages and most likely represent
a release phenomenon that has been generated at the level of the brainstem or spinal cord due
to transient loss of suprasegmental, descending inhibitory influences
Benign neonatal sleep myoclonus
= characterized by symmetric or asymmetric, repetitive jerks of extremities during sleep in the first
month of life. The movements cease upon awakening.
Movements can be mistaken for seizures, but they do not temporally coincide with epileptiform
discharges (EEG)
Benign and resolve over weeks to month
Isolated sleep paralysis (ISP)
= isolated or recurrent episodes of transient inability to move the body as one is drifting off to sleep, or
immediately upon awakening from sleep.
Not accompanied by features of narcolepsy (EDS or cataplexy)
Results from intrusion of REM sleep like muscle atonia onto wakefulness
Is common in adolescents and young adults (6.2% of subjects aged >15 years experienced at
least one episode in their lifetime and 12.4% had experienced onset of symptoms during
childhood)
Consciousness remains intact during episodes -> the individual is aware of the surroundings
Hallucinations such as a feeling the presence of others nearby, pressure on the chest, or hearing
footsteps are common.
20% of young adults with anxiety disorder can manifest ISP but sleep deprivation in healthy
teenagers may also be a trigger.
The differential diagnosis includes partial seizures and periodic paralysis.
Isolated events do not require treatment. Recurrent episodes may be treated with REM
suppressing agents such as low doses of tricyclic agents, clonidine or clonazepam
Rhythmic movement disorder
Rhythmic movements in infants and toddlers at the time of drifting off from wakefulness to sleep are
physiologic and generally resolve by the age of 3-4 years.
They generally occur at the transition from wakefulness to N1, during NREM sleep and in REM
sleep.
Infrequently, the movements occur in the middle of the night after the child has awakened and
is then trying to fall back to sleep.
What are parasomnias?
Phylogeny, ontogeny and pathophysiology
REM and NREM sleep develop from undifferentiated pre-sleep activity in utero. With progressive
maturation, independent oscillations of neuronal activity, autonomic function and overt behavior
become organized into distinct sleep stages like REM and NREM sleep (also called active and quiet
sleep-in newborns).
At 29 weeks post-conception about 20% is transitional (indeterminate sleep) that shows
intermingling of elements of active and quiet sleep.
o With progressive cortical maturation over the next few weeks, indeterminate sleep
seems to resolve.
Another important feature of newborn sleep is the presence of non-epileptic, stereotyped motor
patterns, like bicycling moving during sleep.
o Are a result of the immature cortical neuronal network (incomplete myelination of the
descending motor projection systems), combined with an immature cerebellar system.
Parasomnias are the consequence of dissociation between wakefulness, NREM or REM sleep with
behaviors characteristic of one state becoming superimposed on another.
Generation of non-epileptic stereotyped movements at subcortical levels is related to activation
of networks of interneuron = central pattern generators (CPGs), which in turn recruit motor
neurons in the ventral brainstem or spinal cord as the final, effector step in the elicitation of
stereotypic movements.
o CPG in pons/medulla -> mastication,
o CPG in spinal cord -> walking
o CPGs can be activated by glutaminergic and serotonergic inputs
NMDA receptor antagonists suppress activity of spinal CPGs
Descending serotonergic projections from the raphe nucleus to the spinal cord
also play a complex role in modulating spontaneous and synchronous rhythmic
activities generated at the spinal level.
o Genetic factors and underlying sleep disorders may activate spinal or brainstem CPGs ->
based upon the nature of the CPG that has been activated, one may observe
sleepwalking, rhythmic movement disorder, head banging, bruxism, or other stereotyped
behaviors in sleep.
Arousals = adaptive responses of the sleep regulatory system -> exhibit diverse EEG patterns
o They are also reflected in the phase A subtypes of cyclic alternating patterns (CAPs).
CAPs = ultra-slow EEG oscillations in NREM (20-40s periodicity) that organize sleep
dynamically.
CAPs can trigger stereotypic events in sleep, like epileptic seizures to nocturnal
myoclonus, bruxism and sleepwalking.
What provokes parasomnias in childhood:
Synaptic pruning around 8 months in visual cortex and by 24 months in frontal cortex ->
removal of excess of excitatory and inhibitory synapses.
o Also occurs in the cerebellum and brainstem -> in the cerebellum, the activation of the
NMDA glutamate receptor is involved.
o Concurrently, a process of programmed cell death is also initiated in the CNS
Down-regulation of descending GABAergic projections from the cerebral cortex to the brainstem
or diminished serotonergic inhibition of the spinal cord may play a key role in the pathogenesis
of sleep-wake transition parasomnias and the arousal parasomnias. These changes may also
impact the regulation of CAPs.
o Around age 2, a combination of genetic predisposition to sleep state dissociation,
completion of myelination of the pyramidal tracts and maturation of the cerebellar
system, combined with reflex activation of subcortical central pattern generators triggers
certain stereotypic patterns of behavior
At sleep onset, these patterns may manifest as hypnic starts, sleep paralysis or
rhythmic movements, while during sleep they manifest as confusional arousals,
sleep terrors or sleepwalking
, oThis hypothesis is further supported by the prompt resolution of most parasomnias upon
treatment with GABAergic agents like the benzodiazepines
Explains why parasomnias the period from birth-18 months = silent period for parasomnias ->
overt expression is minimal.
o Parasomnias overtly manifest in pre-school age children and resolve by the latter half of
the first decade (concurrent with progressive maturation of subcortical inhibitory
projection systems), only to reappear in some adults.
Epidemiology
Study general population: 45% of children aged 4-16 years have experienced sleepwalking, but
only 2-3% had at least one episode per month.
o Frightened awakenings from sleep in about 40% and 3.5% met criteria for sleep terrors
Study childhood parasomnias: 14.5% sleepwalking, 39.8% sleep terrors, 25% sleep enuresis,
45.6% bruxism, 9.2% rhythmic movements
o Occurrence of parasomnias in pre-school aged children is quite ubiquitous -> children
frequently experience minor episodes of partial awakening from sleep
o 88% in study cohort manifested at least one parasomnia during the study period
What are the different types of parasomnias?
Sleep-wake transition parasomnias
Hypnic starts
Also termed sleep starts = isolated, quick jerks of the upper or lower extremities at sleep onset. They
might be accompanied by a sensation of falling, a dream-like feeling or a flashing sensation.
They are benign, occurring in approximately 70% of people of all ages and most likely represent
a release phenomenon that has been generated at the level of the brainstem or spinal cord due
to transient loss of suprasegmental, descending inhibitory influences
Benign neonatal sleep myoclonus
= characterized by symmetric or asymmetric, repetitive jerks of extremities during sleep in the first
month of life. The movements cease upon awakening.
Movements can be mistaken for seizures, but they do not temporally coincide with epileptiform
discharges (EEG)
Benign and resolve over weeks to month
Isolated sleep paralysis (ISP)
= isolated or recurrent episodes of transient inability to move the body as one is drifting off to sleep, or
immediately upon awakening from sleep.
Not accompanied by features of narcolepsy (EDS or cataplexy)
Results from intrusion of REM sleep like muscle atonia onto wakefulness
Is common in adolescents and young adults (6.2% of subjects aged >15 years experienced at
least one episode in their lifetime and 12.4% had experienced onset of symptoms during
childhood)
Consciousness remains intact during episodes -> the individual is aware of the surroundings
Hallucinations such as a feeling the presence of others nearby, pressure on the chest, or hearing
footsteps are common.
20% of young adults with anxiety disorder can manifest ISP but sleep deprivation in healthy
teenagers may also be a trigger.
The differential diagnosis includes partial seizures and periodic paralysis.
Isolated events do not require treatment. Recurrent episodes may be treated with REM
suppressing agents such as low doses of tricyclic agents, clonidine or clonazepam
Rhythmic movement disorder
Rhythmic movements in infants and toddlers at the time of drifting off from wakefulness to sleep are
physiologic and generally resolve by the age of 3-4 years.
They generally occur at the transition from wakefulness to N1, during NREM sleep and in REM
sleep.
Infrequently, the movements occur in the middle of the night after the child has awakened and
is then trying to fall back to sleep.
