Sleep paralysis

Clinic

• Sleep paralysis is a state during waking up or falling asleep, in which one is conscious but is completely paralyzed.
• He may hallucinate (hear, feel, or see things that are not there), which often results in fear.
• Episodes generally last less than a couple of minutes. It can recur or occur as a single episode.
  • ISP (Isolated Sleep Paralysis): When episodes occur independent of these conditions or substance use
  • RISP (Recurrent Isolated Sleep Paralysis): When ISP episodes are more frequent and cause clinically significant distress or interference.
• It can be triggered by sleep deprivation, psychological stress, or abnormal sleep cycles.
• Diagnosis is based on a person's description.
• Other conditions that can present similarly include
  • Narcolepsy: It may occur in those who are otherwise healthy or those with narcolepsy
  • Atonic seizure
  • Hypokalemic periodic paralysis
  • RBD: The underlying mechanism is believed to involve a dysfunction in REM sleep.

Note:

Lucid dreaming doesn't affect the chances of sleep paralysis but some lucid dreamers use this as a method of having a lucid dream.

Symptoms / Signs

• The main symptom of sleep paralysis is being unable to move or speak during awakening.
• Imagined sounds such as humming, hissing, static, zapping and buzzing noises are reported during sleep paralysis.
• Other sounds such as voices, whispers and roars are also experienced.
• It has also been known that one may feel pressure on their chest and intense pain in their head during an episode.
• These symptoms are usually accompanied by intense emotions such as fear and panic.
• People also have sensations of being dragged out of bed or of flying, numbness, and feelings of electric tingles or vibrations running through their body.
• Sleep paralysis may include hallucinations, such as an intruding presence or dark figure in the room, suffocating or the individual feeling a sense of terror, accompanied by a feeling of pressure on one's chest and difficulty breathing.

Pathophysiology

• The pathophysiology of sleep paralysis has not been concretely identified, although there are several theories about its cause.
• The first of these stems from the understanding that sleep paralysis is a parasomnia resulting from dysfunctional overlap of the REM and waking stages of sleep.
• Polysomnographic studies found that individuals who experience sleep paralysis have shorter REM sleep latencies than normal along with shortened NREM and REM sleep cycles, and fragmentation of REM sleep. This study supports the observation that disturbance of regular sleeping patterns can precipitate an episode of sleep paralysis, because fragmentation of REM sleep commonly occurs when sleep patterns are disrupted and has now been seen in combination with sleep paralysis.
• Another major theory is that the neural functions that regulate sleep are out of balance in such a way that causes different sleep states to overlap. In this case, cholinergic sleep “on” neural populations are hyperactivated and the serotonergic sleep “off” neural populations are under-activated. As a result, the cells capable of sending the signals that would allow for complete arousal from the sleep state, the serotonergic neural populations, have difficulty in overcoming the signals sent by the cells that keep the brain in the sleep state. During normal REM sleep, the threshold for a stimulus to cause arousal is greatly elevated. Under normal conditions, medial and vestibular nuclei, cortical, thalamic, and cerebellar centers coordinate things such as head and eye movement, and orientation in space.

In individuals reporting sleep paralysis, there is almost no blocking of exogenous stimuli, which means it is much easier for a stimulus to arouse the individual. The vestibular nuclei in particular has been identified as being closely related to dreaming during the REM stage of sleep. According to this hypothesis, vestibular-motor disorientation, unlike hallucinations, arise from completely endogenous sources of stimuli.

If the effects of sleep “on” neural populations cannot be counteracted, characteristics of REM sleep are retained upon awakening. Common consequences of sleep paralysis include headaches, muscle pains or weakness or paranoia. As the correlation with REM sleep suggests, the paralysis is not complete: use of EOG traces shows that eye movement is still possible during such episodes; however, the individual experiencing sleep paralysis is unable to speak.

Research has found a genetic component in sleep paralysis. The characteristic fragmentation of REM sleep, hypnopompic, and hypnagogic hallucinations have a heritable component in other parasomnias, which lends credence to the idea that sleep paralysis is also genetic. Twin studies have shown that if one twin of a monozygotic pair (identical twins) experiences sleep paralysis that other twin is very likely to experience it as well. The identification of a genetic component means that there is some sort of disruption of a function at the physiological level. Further studies must be conducted to determine whether there is a mistake in the signaling pathway for arousal as suggested by the first theory presented, or whether the regulation of melatonin or the neural populations themselves have been disrupted.

Differential diagnosis

• Exploding head syndrome (EHS) potentially frightening parasomnia, the hallucinations are usually briefer always loud or jarring and there is no paralysis during EHS.
• Nightmare disorder (ND); also REM-based parasomnia
• Sleep terrors (STs) potentially frightening parasomnia but are not REM based and there is a lack of awareness to surroundings, characteristic screams during STs.
• Noctural panic attacks (NPAs) involves fear and acute distress but lacks paralysis and dream imagery
• Post-traumatic stress disorder (PTSD) often includes scary imagery and anxiety but not limited to sleep-wake transitions

Miasms

• RBS: I decide to categorize RBD based on their underlying miasm. Sleep paralysis / Catathrenia is one of them and the best miasm is RBS because of making strange voice in his throat

• INFL: It also cover delirium, Apnea.