Sleep paralysis in the elderly

Isolated sleep paralysis (SP) is a common sleep phenomenon that is highly c olored by indigenous beliefs, In Hong Kong Chinese, the 'ghost oppression p henomenon: (GO) has been shown to be descriptively identical to SP. The pre vailing concept is that the majority of cases with SP have their onset duri ng adolescence, but the lack of any systematic study on an older population means that late-onset cases can not be excluded. In a study investigating the prevalence of mental disorders in Chinese elderly aged above 70 y in Ho ng Kong, we employed the revised GO questionnaire to study the prevalence o f SP in this group of elderly as well. One hundred and fifty-eight subjects were finally analyzed for the study. Almost 18% (95% C.I. 11.17%, 23.68%) of the subjects reported experiences of GO, Their description of the featur es of GO showed striking similarity to those of SP, There was a clear bimod al distribution of onset of GO with peaks during adolescence and after age 60 y. At least one-third of the cases were late onset, In concordance with the rapid eye movement (REM)/ wakefulness dissociation hypothesis of SP, th ose elderly with GO + experiences also had more frequent nocturnal sleep di sturbances, A family history was reported in 10% of subjects.