The 1000 Day Holiday

Dr Andrew Ng, director of the Centre for Sleep Disorders and Respiratory Failure at St George Hospital, said sleep paralysis was perhaps the most common sleep disorder.

But, Ng said, despite its prevalence, there had been little research.

During a typical episode, the affected person awoke, and, even though fully conscious, could not move or speak, Ng said.

It could last seconds or even minutes, although it often feels much longer.

About three-quarters of the time, Ng said, it was accompanied by hallucinations that could include a feeling of floating, hearing noises such as people talking, laughing and humming, or even seeing things, such as another person in the room.

As well, said Ng, a feeling of a “threatening presence” was common, and the sense that someone or something was pressing on the person’s chest.

Ng said that while sleep paralysis was not completely understood, there were explanations for the often frightening symptoms, which involved some of the physical characteristics of REM (rapid eye movement) sleep being carried on for a short time during wakefulness.

During REM sleep there was extreme muscle weakness, which explained the lack of movement. It was also the time at which vivid and sometimes terrifying dreams occurred, explaining the hallucinations. The sense of an “evil presence” was, Ng said, in part due to a particular section of the brain being activated without reassurance from the other senses, such as sight and hearing, that the person was safe.

Sleep Paralysis