Relations among hypnagogic and hypnopompic experiences associated with sleep paralysis
Journal of Sleep Research December 1, 1999 J. Allan Cheyne, Ian R. Newby‐Clark, Steve D. Rueffer
A new scale, the Waterloo Sleep Experiences Scale, measures the prevalence of sleep paralysis and related hallucinoid experiences such as sensed presence, pressure, floating, and auditory or visual hallucinations. Among 870 university students, nearly 30% reported at least one sleep paralysis episode. About three-quarters of those also reported hallucinoid experiences, and over 10% experienced three or more. Fear was positively linked to hallucinoid experiences, especially sensed presence. Regression analyses suggest that sensed presence and fear are basic features of sleep paralysis that may lead to further hallucinoid experiences, particularly visual ones.