scholarly journals 0280 Change in Sleep Depth Across the Night as a Measure of Sleep Adequacy

SLEEP ◽  
2020 ◽  
Vol 43 (Supplement_1) ◽  
pp. A106-A106
Author(s):  
P K Schweitzer ◽  
K Griffin ◽  
M Younes ◽  
J K Walsh
Keyword(s):  
Spectral Power ◽  
Secondary Analysis ◽  
Nrem Sleep ◽  
Sleep Time ◽  
Sleep Restriction ◽  
Continuous Measure ◽  
Delta Power ◽  
Sleep Depth ◽  
Sleep Adequacy ◽  
The Individual

Abstract Introduction It is well known that sleep becomes lighter towards the end of the night reflecting the reduction in homeostatic sleep pressure. We hypothesized that more adequate nocturnal sleep (i.e. sufficient quantity and quality for the individual) would result in a greater reduction in sleep depth across the night and would be reflected in decreased next-day sleep tendency. Methods In a secondary analysis of data from a study in which sleep depth was altered by sleep restriction combined with either placebo or gaboxadol (a delta-promoting drug) we correlated change across the night in two measures of sleep depth with next-day Multiple Sleep Latency Test (MSLT) latencies. Forty-one healthy subjects underwent 8 consecutive sleep studies; two baseline, four sleep restriction (5 hours) and two recovery nights. MSLT was performed following each baseline night and the last two restriction nights. Sleep depth in the first and last hours of NREM sleep was determined by two methods 1) Log delta spectral power; 2) The odds-ratio-product (ORP), a recently introduced continuous measure of sleep depth. The difference between initial and final values was calculated (ΔDelta, ΔORP). Post-restriction MSLT latency was correlated with baseline MSLT latency, ΔDelta, ΔORP, log delta power and ORP in the last hour, lost total sleep time and lost REM time. Results ΔDelta was -0.27 ±0.13 and ΔORP was 0.17 ±0.13, both changes reflecting lightening of sleep across the night. In both univariate and multivariate analysis only baseline MSLT latency (p &lt 0.001) and ΔORP (p &lt 0.01) were significantly and positively correlated with post-restriction MSLT latency. Conclusion The reduction in sleep depth across the night as measured by ORP, but not by delta power, is significantly correlated with reduced objective sleepiness following sleep restriction. ΔORP may be a useful index that reflects sleep adequacy during the night. Support None

scholarly journals 0150 Comparing Two Measures of Sleep Depth/ Intensity

SLEEP ◽  
2020 ◽  
Vol 43 (Supplement_1) ◽  
pp. A59-A59
Author(s):  
M Younes ◽  
P K Schweitzer ◽  
K Griffin ◽  
J K Walsh ◽  
R Balshaw
Keyword(s):  
Spectral Power ◽  
Secondary Analysis ◽  
Sleep Restriction ◽  
Sleep Stages ◽  
Continuous Measure ◽  
Characteristic Analysis ◽  
Experimental Conditions ◽  
Delta Power ◽  
Sleep Depth ◽  
Two Measures

Abstract Introduction There is currently no well-validated method for evaluating objective sleep depth/intensity. Delta power is thought to reflect sleep depth based upon limited evidence. Odds-ratio-product (ORP) is a recently introduced continuous measure of sleep depth. We compared delta spectral power (delta) and ORP as measures of sleep depth/intensity during manipulations that altered sleep depth (sleep restriction with placebo or with a delta-promoting drug). We hypothesized that ORP will provide a more robust measure of sleep depth. Methods This is a secondary analysis of data from a study in which forty-one healthy subjects were sleep restricted and randomized to receive placebo or gaboxadol 15mg. Participants underwent consecutive in-laboratory sleep studies on two baseline, four sleep restriction (5 hours) and two recovery nights. The relation between delta or ORP during any given 30s epoch and sleep depth, operationally defined as the probability of arousal / awakening occurring during the next 30 seconds (arousability), was assessed. Results Mean ORP values differed significantly among the four sleep / wake stages, but delta power did not differentiate wake, N1 and N2. The relation between ORP and arousability was linear across the entire range of ORP whereas delta power detected differences in arousability only with delta values &lt 300 μV2. Correlations with arousability in individual subjects were stronger with ORP (p &lt 0.0001). Receiver operating characteristic analysis found the ability to predict imminent arousal to be significantly greater with ORP than with delta power for all experimental conditions (p &lt 0.0001). The increase in sleep depth with restriction alone was detected on the second day of restriction by ORP (p &lt 0.01) but not by delta. Conclusion As compared to delta power, ORP is more discriminating among sleep stages, more sensitive to sleep restriction, and more closely associated with arousability. These observations indicate ORP better reflects sleep depth/intensity. Support None

scholarly journals Comparing two measures of sleep depth/intensity

SLEEP ◽  
2020 ◽  
Vol 43 (12) ◽  
Author(s):  
Magdy Younes ◽  
Paula K Schweitzer ◽  
Kara S Griffin ◽  
Robert Balshaw ◽  
James K Walsh
Keyword(s):  
Spectral Power ◽  
Secondary Analysis ◽  
Sleep Restriction ◽  
Sleep Stages ◽  
Characteristic Analysis ◽  
Experimental Conditions ◽  
Delta Power ◽  
Sleep Depth ◽  
Two Measures ◽  
Degree Of Association

Abstract Study Objectives To compare delta spectral power (delta) and odds ratio product (ORP) as measures of sleep depth during sleep restriction with placebo or a drug that increases delta. Methods This is a secondary analysis of data from a study of 41 healthy participants randomized to receive placebo or gaboxadol 15 mg during sleep restriction. Participants underwent in-laboratory sleep studies on two baseline, four sleep restriction (5-h), and two recovery nights. Relation between delta or ORP and sleep depth was operationally defined as the degree of association of each metric to the probability of arousal or awakening occurring during the next 30 s (arousability). Results ORP values in wake, N1, N2, N3, and REM were significantly different. Delta differed between both N2 and N3 and other sleep stages but not between wake and N1 or N1 and REM. Epoch-by-epoch and individual correlations between ORP and delta power were modest or insignificant. The relation between ORP and arousability was linear across the entire ORP range. Delta also changed with arousability but only when delta values were less than 300 μV2. Receiver-operating-characteristic analysis found the ability to predict imminent arousal to be significantly greater with ORP than with log delta power for all experimental conditions. Changes in ORP, but not log delta, across the night correlated with next-day physiologic sleep tendency. Conclusions Compared to delta power, ORP is more discriminating among sleep stages, more sensitive to sleep restriction, and more closely associated with arousability. This evidence supports ORP as a measure of sleep depth/intensity.

scholarly journals 0324 Effect of Sleep Restriction on Sleep Electroencephalogram Waveforms in Adolescents

SLEEP ◽  
2020 ◽  
Vol 43 (Supplement_1) ◽  
pp. A123-A123
Author(s):  
I G Campbell ◽  
A Cruz Basilio ◽  
Z Y Zhang ◽  
N Darchia ◽  
I Feinberg
Keyword(s):  
Total Sleep Time ◽  
Nrem Sleep ◽  
Sleep Time ◽  
Sleep Restriction ◽  
Sleep Spindles ◽  
Alpha Power ◽  
The Past ◽  
Delta Power ◽  
Eeg Power ◽  
Eeg Recordings

Abstract Introduction Over the past 18 years, our laboratory has been carrying out longitudinal studies of sleep and sleep need across adolescence. Our current study uses a dose-response design to examine daytime performance and sleep EEG after varied sleep durations. Here we present results for 1-30 Hz EEG power in NREM and REM sleep. Methods Home EEG recording in children 10-16 years old (N=77, mean age = 13.2). Adhering to their habitual rise time participants kept an assigned TIB schedule of 7, 8.5, or 10 hours for four consecutive nights. Participants completed all three conditions each year of the 3 year study. EEG recordings from the fourth night of each condition were scored and analyzed with FFT. Results Reducing TIB from 10 to 7 hours effectively decreased total sleep time (TST) from an average of 531 min to an average of 407 min. Decreasing TIB (from 10 to 7 h) produced a small increase (4.6%, p=0.0004) in delta (1-4 Hz) power and a larger decrease (9.0%, p=0.0032) in alpha (8-11 Hz) power in the first 5 h of NREM sleep. In REM periods 2 and 3, the same TIB reduction also increased (12.1%, p<0.0001) delta power and decreased (14.2%, p<0.0001) alpha power. Decreasing TIB reduced (11%, p<0.0001) sigma (11-15 Hz) power in the first 5h of NREM sleep and reduced (28%, p<0.0001) all night NREM sigma energy. Conclusion Reducing TST changes EEG power in several frequency bands. The increase in NREM delta power, expected from homeostatic models, may be too small to be biologically significant. The larger loss of sigma power may be of greater consequence. Sigma frequency activity is an indicator of sleep spindles which have been affected in aging, learning, memory and psychopathology. The sigma response to sleep restriction could be used to study these relations. Support PHS grant R01 HL116490 supported this work.

072 Sleep Spindle Harmonics in Insomnia

SLEEP ◽  
2021 ◽  
Vol 44 (Supplement_2) ◽  
pp. A29-A30
Author(s):  
Michael Goldstein ◽  
Monika Haack ◽  
Janet Mullington
Keyword(s):  
Spectral Power ◽  
Nrem Sleep ◽  
Sleep Time ◽  
Sleep Spindle ◽  
Time Frequency ◽  
Insomnia Disorder ◽  
Spectral Peaks ◽  
Limited Application ◽  
Thalamic Relay Nuclei ◽  
Restorative Sleep

Abstract Introduction Prior research has reported NREM spectral EEG differences between individuals with insomnia and good-sleeper controls, including elevated high-frequency EEG power (beta/gamma bands, ~16-50Hz) and, to a lesser extent, elevations in sleep spindle parameters. However, the mechanisms driving these differences remain unclear. Harmonics have been observed in EEG data as spectral peaks at multiples of a fundamental frequency associated with an event (e.g., for a 14Hz spindle, the 2nd harmonic is expected to be a peak at 28Hz). Thus far, there has been very limited application of this idea of spectral harmonics to sleep spindles, even though these patterns can indeed be seen in some existing literature. We sought to build on this literature to apply spectral harmonic analysis to better understand differences between insomnia and good sleepers. Methods 15 individuals with insomnia disorder (DSM-5 criteria, 13 female, age 18–32 years) and 15 good-sleeper controls (matched for sex, age, and BMI) completed an overnight polysomnography recording in the laboratory and subsequent daytime testing. Insomnia diagnosis was determined by a board-certified sleep specialist, and exclusion criteria included psychiatric history within past 6 months, other sleep disorders, significant medical conditions, and medications with significant effects on inflammation, autonomic function, or other psychotropic effects. Results Consistent with prior studies, we found elevated sleep spindle density and fast sigma power (14-16Hz). Despite no difference in beta or gamma band power when averaged across NREM sleep, time-frequency analysis centered on the peaks of detected spindles revealed a phasic elevation in spectral power surrounding the 28Hz harmonic peak in the insomnia group, especially for spindles coupled with slow waves. We also observed an overall pattern of time-locked delay in the 28Hz harmonic peak, occurring approximately 40 msec after spindle peaks. Furthermore, we observed a 42Hz ‘3rd harmonic’ peak, not yet predicted by the existing modeling work, which was also elevated for insomnia. Conclusion In conjunction with existing mathematical modeling work that has linked sleep spindle harmonic peaks with thalamic relay nuclei as the primary generators of this EEG signature, these findings may enable novel insights into specific thalamocortical mechanisms of insomnia and non-restorative sleep. Support (if any) NIH 5T32HL007901-22

scholarly journals Differential modulation of NREM sleep regulation and EEG topography by chronic sleep restriction in mice

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Bowon Kim ◽  
Eunjin Hwang ◽  
Robert E. Strecker ◽  
Jee Hyun Choi ◽  
Youngsoo Kim
Keyword(s):  
Nrem Sleep ◽  
Brain Regions ◽  
Sleep Eeg ◽  
Sleep Restriction ◽  
Electrode Arrays ◽  
Sleep Regulation ◽  
Amplitude Analysis ◽  
Delta Power ◽  
Eeg Topography ◽  
Chronic Sleep

AbstractCompensatory elevation in NREM sleep EEG delta power has been typically observed following prolonged wakefulness and widely used as a sleep homeostasis indicator. However, recent evidence in human and rodent chronic sleep restriction (CSR) studies suggests that NREM delta power is not progressively increased despite of accumulated sleep loss over days. In addition, there has been little progress in understanding how sleep EEG in different brain regions responds to CSR. Using novel high-density EEG electrode arrays in the mouse model of CSR where mice underwent 18-h sleep deprivation per day for 5 consecutive days, we performed an extensive analysis of topographical NREM sleep EEG responses to the CSR condition, including period-amplitude analysis of individual slow waves. As previously reported in our analysis of REM sleep responses, we found different patterns of changes: (i) progressive decrease in NREM sleep duration and consolidation, (ii) persistent enhancement in NREM delta power especially in the frontal and parietal regions, and (iii) progressive increases in individual slow wave slope and frontal fast oscillation power. These results suggest that multiple sleep-wake regulatory systems exist in a brain region-specific manner, which can be modulated independently, especially in the CSR condition.

scholarly journals The European starling (Sturnus vulgaris) shows signs of NREM sleep homeostasis but has very little REM sleep and no REM sleep homeostasis

SLEEP ◽  
2019 ◽  
Vol 43 (6) ◽  
Author(s):  
Sjoerd J van Hasselt ◽  
Maria Rusche ◽  
Alexei L Vyssotski ◽  
Simon Verhulst ◽  
Niels C Rattenborg ◽  
...  
Keyword(s):  
Sleep Deprivation ◽  
Eye Movement ◽  
Rem Sleep ◽  
Spectral Power ◽  
Nrem Sleep ◽  
Sleep Time ◽  
European Starling ◽  
Dark Phase ◽  
Rapid Eye Movement ◽  
Sleep Homeostasis

Abstract Most of our knowledge about the regulation and function of sleep is based on studies in a restricted number of mammalian species, particularly nocturnal rodents. Hence, there is still much to learn from comparative studies in other species. Birds are interesting because they appear to share key aspects of sleep with mammals, including the presence of two different forms of sleep, i.e. non-rapid eye movement (NREM) and rapid eye movement (REM) sleep. We examined sleep architecture and sleep homeostasis in the European starling, using miniature dataloggers for electroencephalogram (EEG) recordings. Under controlled laboratory conditions with a 12:12 h light–dark cycle, the birds displayed a pronounced daily rhythm in sleep and wakefulness with most sleep occurring during the dark phase. Sleep mainly consisted of NREM sleep. In fact, the amount of REM sleep added up to only 1~2% of total sleep time. Animals were subjected to 4 or 8 h sleep deprivation to assess sleep homeostatic responses. Sleep deprivation induced changes in subsequent NREM sleep EEG spectral qualities for several hours, with increased spectral power from 1.17 Hz up to at least 25 Hz. In contrast, power below 1.17 Hz was decreased after sleep deprivation. Sleep deprivation also resulted in a small compensatory increase in NREM sleep time the next day. Changes in EEG spectral power and sleep time were largely similar after 4 and 8 h sleep deprivation. REM sleep was not noticeably compensated after sleep deprivation. In conclusion, starlings display signs of NREM sleep homeostasis but the results do not support the notion of important REM sleep functions.

scholarly journals Insomnia subtypes characterised by objective sleep duration and NREM spectral power and the effect of acute sleep restriction: an exploratory analysis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Chien-Hui Kao ◽  
Angela L. D’Rozario ◽  
Nicole Lovato ◽  
Rick Wassing ◽  
Delwyn Bartlett ◽  
...  
Keyword(s):  
Sleep Duration ◽  
Spectral Power ◽  
Power Spectral Analysis ◽  
Asymmetry Index ◽  
Sleep Restriction ◽  
Healthy Controls ◽  
Sleep State ◽  
Subjective Sleep Quality ◽  
Delta Power ◽  
Normal Sleep

AbstractInsomnia disorder (ID) is a heterogeneous disorder with proposed subtypes based on objective sleep duration. We speculated that insomnia subtyping with additional power spectral analysis and measurement of response to acute sleep restriction may be informative in overall assessment of ID. To explore alternative classifications of ID subtypes, insomnia patients (n = 99) underwent two consecutive overnight sleep studies: (i) habitual sleep opportunity (polysomnography, PSG) and, (ii) two hours less sleep opportunity (electroencephalography, EEG), with the first night compared to healthy controls (n = 25). ID subtypes were derived from data-driven classification of PSG, EEG spectral power and interhemispheric EEG asymmetry index. Three insomnia subtypes with different sleep duration and NREM spectral power were identified. One subtype (n = 26) had shorter sleep duration and lower NREM delta power than healthy controls (short-sleep delta-deficient; SSDD), the second subtype (n = 51) had normal sleep duration but lower NREM delta power than healthy controls (normal-sleep delta-deficient; NSDD) and a third subtype showed (n = 22) no difference in sleep duration or delta power from healthy controls (normal neurophysiological sleep; NNS). Acute sleep restriction improved multiple objective sleep measures across all insomnia subtypes including increased delta power in SSDD and NSDD, and improvements in subjective sleep quality for SSDD (p = 0.03), with a trend observed for NSDD (p = 0.057). These exploratory results suggest evidence of novel neurophysiological insomnia subtypes that may inform sleep state misperception in ID and with further research, may provide pathways for personalised care.

Insomnia subtypes characterised by objective sleep duration and NREM spectral power and the effect of acute sleep restriction: an exploratory analysis

2021 ◽  
Author(s):  
Chien-Hui Kao ◽  
Angela L. D'Rozario ◽  
Nicole Lovato ◽  
Rick Wassing ◽  
Delwyn Bartlett ◽  
...  
Keyword(s):  
Sleep Duration ◽  
Spectral Power ◽  
Power Spectral Analysis ◽  
Asymmetry Index ◽  
Sleep Restriction ◽  
Healthy Controls ◽  
Sleep State ◽  
Subjective Sleep Quality ◽  
Delta Power ◽  
Normal Sleep

Abstract Insomnia disorder (ID) is a heterogeneous disorder with proposed subtypes based on objective sleep duration. We speculated that insomnia subtyping with additional power spectral analysis and measurement of response to acute sleep restriction may be informative in overall assessment of ID. To explore alternative classifications of ID subtypes, insomnia patients (n = 99) underwent two consecutive overnight sleep studies: (i) habitual sleep opportunity (polysomnography, PSG) and, (ii) two hours less sleep opportunity (electroencephalography, EEG), with the first night compared to healthy controls (n = 25). ID subtypes were derived from data-driven classification of PSG, EEG spectral power and interhemispheric EEG asymmetry index. Three insomnia subtypes with different sleep duration and NREM spectral power were identified. One subtype (n = 26) had shorter sleep duration and lower NREM delta power than healthy controls (short-sleep delta-deficient; SSDD), the second subtype (n = 51) had normal sleep duration but lower NREM delta power than healthy controls (normal-sleep delta-deficient; NSDD) and a third subtype showed (n = 22) no difference in sleep duration or delta power from healthy controls (normal neurophysiological sleep; NNS). Acute sleep restriction improved multiple objective sleep measures across all insomnia subtypes including increased delta power in SSDD and NSDD, and improvements in subjective sleep quality for SSDD (p = 0.03), with a trend observed for NSDD (p = 0.057). These exploratory results suggest evidence of novel neurophysiological insomnia subtypes that may inform sleep state misperception in ID and with further research, may provide pathways for personalised care.

Time-of-day modulation of homeostatic and allostatic sleep responses to chronic sleep restriction in rats

2012 ◽  
Vol 302 (12) ◽  
pp. R1411-R1425 ◽  
Author(s):  
S. Deurveilher ◽  
B. Rusak ◽  
K. Semba
Keyword(s):  
Eye Movement ◽  
Recovery Period ◽  
Sleep Time ◽  
Time Of Day ◽  
Male Rats ◽  
Sleep Restriction ◽  
Rapid Eye Movement ◽  
Rapid Eye Movement Sleep ◽  
Delta Power ◽  
Chronic Sleep

To study sleep responses to chronic sleep restriction (CSR) and time-of-day influences on these responses, we developed a rat model of CSR that takes into account the polyphasic sleep patterns in rats. Adult male rats underwent cycles of 3 h of sleep deprivation (SD) and 1 h of sleep opportunity (SO) continuously for 4 days, beginning at the onset of the 12-h light phase (“3/1” protocol). Electroencephalogram (EEG) and electromyogram (EMG) recordings were made before, during, and after CSR. During CSR, total sleep time was reduced by ∼60% from baseline levels. Both rapid eye movement sleep (REMS) and non-rapid eye movement sleep (NREMS) during SO periods increased initially relative to baseline and remained elevated for the rest of the CSR period. In contrast, NREMS EEG delta power (a measure of sleep intensity) increased initially, but then declined gradually, in parallel with increases in high-frequency power in the NREMS EEG. The amplitude of daily rhythms in NREMS and REMS amounts was maintained during SO periods, whereas that of NREMS delta power was reduced. Compensatory responses during the 2-day post-CSR recovery period were either modest or negative and gated by time of day. NREMS, REMS, and EEG delta power lost during CSR were not recovered by the end of the second recovery day. Thus the “3/1” CSR protocol triggered both homeostatic responses (increased sleep amounts and intensity during SOs) and allostatic responses (gradual decline in sleep intensity during SOs and muted or negative post-CSR sleep recovery), and both responses were modulated by time of day.

scholarly journals An attempt to identify reproducible high-density EEG markers of PTSD during sleep

SLEEP ◽  
2019 ◽  
Vol 43 (1) ◽  
Author(s):  
Chao Wang ◽  
Sridhar Ramakrishnan ◽  
Srinivas Laxminarayan ◽  
Andrey Dovzhenok ◽  
J David Cashmere ◽  
...  
Keyword(s):  
Eye Movement ◽  
Rem Sleep ◽  
Spectral Power ◽  
Brain Activity ◽  
Nrem Sleep ◽  
High Density ◽  
Post Traumatic Stress ◽  
Significant Group ◽  
Delta Power ◽  
Regional Brain Activity

Abstract Study Objectives We examined electroencephalogram (EEG) spectral power to study abnormalities in regional brain activity in post-traumatic stress disorder (PTSD) during sleep. We aimed to identify sleep EEG markers of PTSD that were reproducible across nights and subsamples of our study population. Methods Seventy-eight combat-exposed veteran men with (n = 31) and without (n = 47) PTSD completed two consecutive nights of high-density EEG recordings in a laboratory. We performed spectral-topographical EEG analyses on data from both nights. To assess reproducibility, we used the first 47 consecutive participants (18 with PTSD) for initial discovery and the remaining 31 participants (13 with PTSD) for replication. Results In the discovery analysis, compared with non-PTSD participants, PTSD participants exhibited (1) reduced delta power (1–4 Hz) in the centro-parietal regions during nonrapid eye movement (NREM) sleep and (2) elevated high-frequency power, most prominent in the gamma band (30–40 Hz), in the antero-frontal regions during both NREM and rapid eye movement (REM) sleep. These findings were consistent across the two study nights, with reproducible trends in the replication analysis. We found no significant group differences in theta power (4–8 Hz) during REM sleep and sigma power (12–15 Hz) during N2 sleep. Conclusions The reduced centro-parietal NREM delta power, indicating reduced sleep depth, and the elevated antero-frontal NREM and REM gamma powers, indicating heightened central arousal, are potential objective sleep markers of PTSD. If independently validated, these putative EEG markers may offer new targets for the development of sleep-specific PTSD diagnostics and interventions.

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