The Association Between EEG and SleepPerception During MSLT Naps on SubjectsWith Excessive Daytime Sleepiness
Aaron D.Laposky, Ph.D., A.Michael Anch, Ph.D., and Stephen P.Duntley, M.D.
This study investigated the relationship between EEG indexes and perception of sleep
depth (DEPTH)during Multiple Sleep Latency Tests (MSLT).Participants were five males
(X=41.6 years)and six females (X=36.8 years)with clinical complaints of excessive day-
time sleepiness.Each subject had five nap opportunities.Subjects completed the Stanford
Sleepiness Scale (SSS)before each nap and completed a “0-5″point scale to indicate
DEPTH of sleep (DEPTH “0”indicated awake and DEPTH “5”indicated deep sleep)after
each nap.Only naps in which EEG sleep occurred were used for data analysis.Recordings
were scored for standard sleep parameters and SS density.Total sleep time (TST)was pos-
itively correlated with DEPTH.Analysis of variance (ANOVA)showed that TST was signifi-
cantly less for DEPTH “0”compared to DEPTH “1-4”.SS density was positively correlated
with TST but not with DEPTH.ANOVA showed SS density was significantly lower for DEPTH
“0”and DEPTH “4”compared with DEPTH “1-3”.SSS scores were unrelated to TST and
DEPTH scores.These results indicated that TST was associated only with the subjective
experience of being awake versus being asleep.SS density was related to the perception
of intermediate DEPTH levels but not to the deepest level (DEPTH “4”).Decreased SS den-
sity at DEPTH “4”indicated either that SS is not sufficient for accurate sleep perception or
that all sleep states are not homogenous in terms of subjective experience.(Sleep and
Hypnosis 2001;3(2):84-92)
Volume 3, Number 2, Year 2001
