Parasomnia

Clinic

• Parasomnias are a category of sleep disorders that involve abnormal movements, behaviors, emotions, perceptions, and dreams that occur while falling asleep, sleeping, between sleep stages, or during arousal from sleep.
• Parasomnias are dissociated sleep states which are
  • Partial arousals during the transitions between wakefulness
  • NREM sleep
  • REM sleep
  • Their combinations

NREM

• NREM parasomnias are arousal disorders that occur during stage 3 of NREM sleep (Slow wave sleep (SWS)).
• They are caused by a physiological activation in which the patient's brain exits from SWS and is caught in between a sleeping and waking state.
• These disorders involve activation of the autonomic nervous system, motor system, or cognitive processes during sleep or sleep-wake transitions.

Slow-wave sleep arousal parasomnias

Four major members of the slow-wave sleep arousal parasomnias are

1. Enuresis nocturna
2. Somnambulism
3. Sleep terrors (pavor nocturnus in children, incubus attacks in adults)
4. Confusional arousals (sleep drunkenness)

Other parasomnias

• Sleep-related aggression
• Hypnagogic and hypnopompic terrifying hallucinations
• REM sleep terrifying dreams
• Nocturnal anxiety attacks
• Sleep paralysis
• Sleep talking (somniloquy)
• Sexsomnia
• REM sleep behavior disorder (RBD),
• Nocturnal paroxysmal dystonia
• Sleep starts (hypnic jerks)
• Jactatio capitis nocturna (head and total body rocking)
• Periodic limb movement disorder (PLMs)
• Hypnagogic foot tremor
• Restless leg syndrome (Ekbom syndrome)
• Exploding head syndrome
• Excessive fragmentary myoclonus
• Nocturnal cramps
• Sleep-related epileptic seizures

	NREM-related parasomnias	REM-related parasomnias	Other parasomnias	Differential diagnosis
Subtypes	Confusional arousals Somnambulism Night terrors Sleep-eating Sleep-sex Teeth grinding Rhythmic movement disorder Somniloquy	RBD (REM sleep behavior disorder) Recurrent isolated sleep paralysis Nightmare disorder Catathrenia Sleep-Related painful erections	Exploding head syndrome Sleep-related hallucinations Sleep enuresis Parasomnias due to medical disorde Parasomnias due to medication or substance Unspecific Parasomnia	Sleep-disordered breathing REM-related parasomnias Nocturnal seizures Psychogenic dissociative disorders
Core theme	Impairing normal arousal mechanisms leads to Impaired control of executive function Impaired memory / Amnesia	Normal Muscle atonia of REM sleep is absent. So People act their dreams voluntary and they remember it when waking up.
	Impaired arousal mechanisms and the persistence of sleep drive result in a failure of the brain to fully transition into wakefulness. Indeed, most SW and related disorders arise out of N3 sleep	Aberrant connections between the brain-stem and cortex which control of muscle tonicity during REM sleep.
Entities	Altered consciousness Cognition impaired Delirium Psychosis Automatism (Frontal lobe epilepsy)	LMN
	FFI maybe JE	PLV WNE

Sleep centers of brain

• Hypothalamus acts as control center affecting sleep and arousal. 

• Suprachiasmatic nucleus (SCN) receive information about light exposure directly from the eyes and control your behavioral rhythm. 
  • Injury of SCN causes sleeping throughout the day because of Exit setting of circadian rhythms. Most blind people maintain some ability to sense light and are able to modify their sleep/wake cycle.

• Brain stem communicates with hypothalamus to control the transitions between wake and sleep. 
  • Sleep-promoting cells within the hypothalamus and the brain stem produce GABA, which acts to reduce the activity of arousal centers in hypothalamus and brain stem.
  • Brain stem (esp pons and medulla) also plays a special role in REM sleep; it sends signals to relax muscles essential for body posture and limb movements, so that we don’t act out our dreams.

• Thalamus acts as a relay for information from the senses to the cerebral cortex . During most stages of sleep, the thalamus becomes quiet, letting you tune out the external world.  But during REM sleep, thalamus is active, sending the cortex images, sounds, and other sensations that fill our dreams.

• Pineal gland receives signals from SCN and increases production of the hormone melatonin, which helps put you to sleep once the lights go down. 

• Basal forebrain also promotes sleep and wakefulness, while part of the midbrain acts as an arousal system. Release of adenosine ) from basal forebrain and probably other regions supports your sleep drive. 

• Amygdala involved in processing emotions, becomes increasingly active during REM sleep.