The phenomena of both descriptions of ‘psycho sensory hallucinations’ ,was first described by French psychiatrist Bailarger in 1846.
It was a systematic description of vivid perceptions of hallucinations onset of falling asleep,and upon awakening.
“Hypnagogic (or a alternate term-hypnogogic) from the term ‘hypno'(asleep) and ‘agogos’ (induced) was coined by French scholar Louis Ferdinand Alfred Maury in the same year,in term of describing some unusual illusions upon of asleep.
“Hynopompic” derives from the greek word ‘pompe'(act of sending) “coined” by British spiritualist & philosopher Myer to describe hallucinations in the transition between sleep and awakening.
Both terms are often associated by health care professionals as symptoms categorized as “narcolepsy”(sleep attacks usually anytime during the day from a low level of hypocretin in the brain). According to one source it is very common with individuals with mental disorders. I do not buy that, nor am I narcoleptic (and was never diagnosed with this neurological disorder). Narcolepsy has four classic symptoms:
Excessive Daytime Sleepiness
All Narcoleptics in common have these four classic symptoms, as all narcoleptics have sleep paralysis and do have sleep attacks. Not everyone who has undergone awake sleep paralysis is a narcoleptic.
Around some 20 years ago, and once in a great while, I did feel some weakness of the limbs, and a slight jerk of the head and FOP (feeling of presence) as some outlined shape illusion tackled me on top of my bed, as I awoke..it was resembled like that bizarre creature from the movie ‘Predator’ where it blending in the surrounding environment, except it is usually in fuzzy/murky color,and semi-shaped.
It is strange how powerful how our brain activates ,even during the sleep process. If this was to mean ,that heaviness crushing upon people with sleep paralysis,including of a visit from a ‘alien’ . Seems more intense than vivid.
Sleep Paralysis in either predormital or postdormital form is regarded as being found in “creative”,”artistic”,and “sensitive” individuals. I can relate more to the latter.