SLEEP 2011 Abstract Supplement

B. Clinical Sleep Science X. Normal Physiology of Sleep and Normal Variants
0769
TRACKING THE DYNAMICS OF THE EFFECTIVENESS OF
SLEEP
Thomas RJ, Wood C
Medicine, Beth Israel Deaconess Medical Center, Boston, MA, USA
Introduction: Sleep physiology and pathology can be tracked by several
methods-such as multiple nights of polysomnography, oximetry,
and actigraphy. A new method of estimating sleep quality is the ECGspectrogram,
where high frequency cardiopulmonary coupling is the
biomarker of effective and restorative sleep. This biomarker associates
strongly with relative rather than absolute delta power, periods of stable
breathing, strong sinus arrhythmia, and blood pressure dipping. The M1
(Embla) is a device with multi-night recording capability for actigraphy,
ECG and body position.
Methods: 2 weeks of nightly recordings with the M1 were obtained
from 5 healthy adult subjects (age range 22-32, 2 female) screened with
polysomnography to exclude sleep apnea, and one 58-year old male
with sleep apnea. Summary metrics and intra-class coefficients (ICC)
were calculated. Data from 10 subjects (each) with and without sleep
apnea are expected to be available for the meeting. Sleep periods were
estimated from actigraphy.
Results: Analysis of variance showed that within individual night-tonight
variability was not, but variability between subjects were, statistically
significant. With just 6 subjects, the ICC for high, low and very low
frequency % (of estimated sleep period) and duration were, respectively:
0.41, 0.44, 0.13, 0.32, 0.08, and 0.18
Conclusion: Sleep quality can be readily tracked across multiple nights
using the ECG-spectrogram. Intra-individual variability of high frequency
coupling is relatively low, and may represent a stable phenotype.
Effects of sleep therapies could be assessed in a non-intrusive and costeffective
manner.
Support (If Any): NIH/NHLBI RC1 HL099749-01
0770
STABILITY AND REPRODUCIBILITY OF SLEEPINESS AND
SLEEP PROBLEM PHENOTYPES OVER 4-YEAR INTERVALS
IN THE WISCONSIN SLEEP COHORT STUDY
Finn L 1 , Stubbs M 1 , Mignot E 2 , Peppard PE 1
1
Population Health Sciences, University of Wisconsin, Madison, WI,
USA, 2 Stanford University, Palo Alto, CA, USA
Introduction: It is not clear whether sleep-related characteristics—including
objective and subjective sleepiness, insomnia symptoms, and
symptoms associated with narcolepsy—represent “stable phenotypes”
in generally healthy populations unselected on clinical features. To investigate
stability of these sleep-related phenotypes, we examine longerterm
(4-year) consistency of these characteristics in Wisconsin Sleep
Cohort Study participants.
Methods: The Wisconsin Sleep Cohort sample comprises 1524 subjects
(45% female, 33-71 years old) who had baseline in-laboratory sleep
evaluations and sleep-health interviews. Subjects have repeat studies at
4-year intervals. To examine propensity to fall asleep, we used a subset
of 440 subjects who underwent Multiple Sleep Latency Tests (MSLT)
and completed the Epworth Sleepiness Scales (ESS) twice in a 4-year
period. In addition, an overlapping subset of 841 subjects completed
sleep-health interviews assessing narcolepsy and insomnia symptoms,
also at 4-year intervals. We created binary categorizations of the sleep
variables according to standard criteria (e.g., MSLT