Sleep paralysis

is a sleep disorder, or more precisely a parasomnia according to the International Classification of Sleep Disorders, which is characterized by the fact that the subject, about to fall asleep (hypnagogic paralysis) or to awaken (hypnopompic paralysis) but quite conscious, is unable to perform any voluntary movement. To this sensation of immobilization are commonly associated auditory, kinesthetic or visual hallucinations as well as impressions of oppression, suffocation, evil presence and imminent death. The subject, unable to articulate the sounds and to prevent the entourage, most often experiences a feeling of anxiety and fear. This sleep disorder is due to intrusions of paradoxical sleep and the absence of muscle tone that accompanies it during transitions between sleep and wakefulness.