ASP vs Periodic Paralyses
There are a group of disorders called Periodic Paralyses which appear to be related to blood levels of potassium (important for with transmission of nerve impulses).
Awareness during Sleep Paralysis
...can be distinguished from seizures, syncopal episodes, and periodic paralysis by its association with the beginning and end of sleep, by its termination with noise or touch, and by the immediate return to full consciousness when the episode ends.
In addition, episodes of Awareness during Sleep Paralysis are typically short, a matter of minutes. whereas periodic paralysis attacks
... may last from less than one hour to several days.
Source: Periodic Paralysis Association website