All Publications


 

A Comparison of Different Success Definitions in Non-Continuous Positive Airway Pressure Treatment f

Authors:
Woo Hyun Lee, Seung-No Hong, Hong Joong Kim, Chae-Seo Rhee, Chul Hee Lee, In-Young Yoon, Jeong-Whun Kim

Reference:
Journal of Clinical Sleep Medicine 2016;12(1):35–41.

Objectives:
The definition and the criteria for the successful treatment of obstructive sleep apnea vary, depending on the study. This study aimed to compare different success criteria of non-continuous positive airway pressure (non-CPAP) treatment for obstructive sleep apnea in terms of sleep quality by using cardiopulmonary coupling.


 

Conclusions:
Cardiopulmonary coupling analysis showed that a reduction in the apnea-hypopnea index of more than 50% might be the optimal criterion to determine the success or failure of non-CPAP treatment in terms of sleep quality.

Practical Significance:
The parameters of cardiopulmonary coupling indicated that sleep quality improved with non-CPAP treatment: low-frequency coupling decreased from 57.4% ± 17.7% to 46.9% ± 16.5%, whereas high-frequency coupling increased from 30.2% ± 17.1% to 37.4% ± 16.7%. In multiple regression analysis, only the criterion of a reduction in the apnea-hypopnea index greater than 50% was significantly associated with sleep quality improvement (p = 0.016; 95% confidence interval, 1.008–1.076 in the high-frequency coupling increment; p = 0.001; 95% confidence interval, 1.025–1.099 in the low-frequency coupling decrement).

View Publication:

 

A Novel Home Sleep Monitoring Device and Brief Sleep Intervention for Bipolar Disorder: Feasibility, Tolerability, and Preliminary Effectiveness

Authors:
Sylvia,Louisa G., Salcedo,Stephanie , Bianchi,Matt T. , Urdahl,Anna, Nierenberg,Andrew A., Deckersbach,Thilo

Reference:
Cognitive Therapy and Research February 2014, Volume 38, Issue 1, pp 55-61

Objectives:
The purpose of this study is to assess the feasibility and tolerability of a novel EKG-based home sleep monitoring device (M1) as well as a brief (two session) psychosocial sleep intervention for individuals with bipolar disorder. 

Conclusions:
We developed a brief psychosocial sleep intervention for bipolar disorder, as well as explored the feasibility and acceptability of a novel home sleep monitoring device (M1 device). Our data suggest that the brief psychosocial sleep intervention and the M1 device are both tolerable and feasible for participants given (1) their high adherence rates and (2) participants’ initially high expectations remained stable. Although participants reported being less likely to wear the M1 after the intervention, their acceptability rating for this device was still high. We also found that the brief sleep intervention improved sleep duration, but was also associated with more unstable sleep as measured by the M1.

One possibility for the increase in unstable sleep is that the brief sleep intervention may have been overly focused on ways to improve sleep duration as opposed to sleep quality. This may suggest that future sleep interventions for bipolar disorder should focus more on factors that contribute to the degree of restful sleep (e.g., intrusive thoughts, aspects of the sleep environment, ability to self-soothe). Nonetheless, participants slept longer as well as reported less day dysfunction due to sleepiness after receiving the brief sleep intervention. There was also a trend for improvements in other indices (e.g. manic and depressive symptoms, sleep quality) after the sleep intervention, but they did not reach statistical significance in this small sample.

Practical Significance:
All eight participants completed the sleep intervention and attended 100% of the sessions. Seventy five percent of patients were taking a mood stabilizer (e.g., lithium, valproic acid), 13% on anxiolytics/hypnotics (e.g., zolpidem, lorazepam), 50% on antidepressants (e.g., fluoxetine, buproprion), and 13% on antipsychotics (e.g., clozapine, quetiapine). Participants had high expectations for the sleep intervention as they strongly agreed that the intervention would be user friendly (M = 1.75, SD = 0.46), they would learn skills that would help them change (M = 1.88, SD = 0.35), and that they would like using those skills (M = 1.88, SD = 0.64). Most of their expectation scores/ratings did not change after receiving the sleep intervention (p’s >.05), suggesting that the intervention met their initially high expectations. In addition, participants were more likely to report learning skills that they could use on their own (t[7] = 2.65, p < .05), as well as recommend the intervention after receiving it (t[7] = 3.42, p < .05).

In regards to the M1, all participants wore it for at least two nights. The average number of nights the M1 was worn was 6.12 days after Visit 1 (SD = 1.36; Range = 4 to 8 days) and 5.5 days after Visit 3 (SD = 2.33; Range = 2 to 8 days). At Visit 2, participants agreed that the M1 was very easy to use (M = 4.50, SD = 0.54), easy to apply (M = 4.50, SD = 0.76), and did not interfere with their sleep (M = 4.88, SD = 0.35); at the end of the study, there were no statistically significant changes in these items; however, participants were less likely to report that they would wear the device again (t[7] = 3.42, p < .05). Nevertheless, the mean rating was still very high at visit 4 (M = 4.25), indicating that participants reported still being likely to wear the M1 again.

View Publication:

 

Ambulatory screening tool for sleep apnea: analyzing a single-lead electrocardiogram signal (ECG)

Authors:
S Magnusdottir, H Hilmisson

Reference:
Sleep Breath September 2017; DOI 10.1007/s11325-017-1566-6

Objectives:
The goal was to determine the utility and accuracy of automated analysis of single-lead electrocardiogram (ECG) data using two algorithms, cardiopulmonary coupling (CPC), and cyclic variation of heart rate (CVHR) to identify sleep apnea (SA).

Conclusions:
The CPC+CVHR technology performed as accurately as the automated scoring software to identify patients with moderate to severe SA, demonstrating a clinically powerful tool that can be implemented in various clinical settings to identify patients at risk for SA.

Practical Significance:
A high degree of agreement was noted between the CPC-CVHR against both the manually rescored AHI and the computerized scored AHI to identify patients with moderate and severe sleep apnea (AHI > 15). The combined CPC+CVHR algorithms, when compared to the manually scored PSG output presents sensitivity 89%, specificity 79%, agreement 85%, PPV (positive predictive value) 0.86 and NPV (negative predictive value) 0.83, and substantial Kappa 0.70. Comparing the output of the automated scoring software to the manual scoring demonstrated sensitivity 93%, specificity 79%, agreement 87%, PPV 0.87, NPV 0.88, and substantial Kappa 0.74.

View Publication:

 

An Early Indicator of Complex Sleep Apnea

Authors:
Schramm PJ.

Reference:
Advance for Respiratory Care and Sleep Medicine June 21, 2010

Objectives:
Demonstration of the impact on a Complex Sleep Apnea patient’s sleep quality with CPAP versus ASV using CPC to detect stable and unstable sleep.

Conclusions:
CPC variables indicated that the patient’s sleep quality had improved objectively. Subjectively, the patient reported his sleep more restful when using the combination of ASV at 9cm H2O and added dead space compared to CPAP.

Practical Significance:
This study highlights that the presence of e-LFCNB can help identify complex sleep apnea both before and after initiation of PAP therapy. A second CPC study following the application of ASV with dead space showed improved quality of sleep in the form of increased HFC, which corresponded well with the patients subjective findings.

View Publication:

 

An Electrocardiogram-based analysis evaluating sleep quality in patients with obstructive sleep apnea.

Authors:
Harrington J, Schramm PJ, Davies CR, Lee-Chiong TL Jr.

Reference:
Sleep Breath. 2013 Sep;17(3):1071-8.

Objectives:
The study compares polysomnography (PSG) and cardiopulmonary coupling (CPC) sleep quality variables in patients with (1) obstructive sleep apnea (OSA) and (2) successful and unsuccessful continuous positive airway pressure (CPAP) response.

Conclusions:
Tests differentiated no and moderate to severe OSA groups by REM %, HFC, VLFC, and LFC/HFC ratio variables. The successful CPAP therapy group had more HFC, less LFC, and e-LFCBB compared to the unsuccessful CPAP therapy group. HFC ≥ 50 % showed high sensitivity (77.8 %) and specificity (88.9 %) in identifying successful CPAP therapy.

Practical Significance:
The results support the use of the SleepImage system to investigate and objectively measure sleep quality in patients complaining of a sleep disorder.

View Publication:

 

An Electrocardiogram-based Technique to Assess Cardiopulmonary Coupling During Sleep

Authors:
Thomas RJ, Mietus JE, Peng CK, Goldberger AL

Reference:
SLEEP 2005;28:1151-1161

Objectives:
Evaluate a new automated measure of CPC during sleep using a single-lead electrocardiographic (ECG) signal

Conclusions:
A sleep spectrogram derived from information in a single lead electrocardiogram can be used to dynamically track cardiopulmonary interactions. The 2 distinct (bimodal) regimes demonstrate a closer relationship with visual cyclic alternating pattern (CAP) and non-cyclic alternating pattern states than with standard sleep stages. This technique may provide a complementary approach to the conventional characterization of graded non-rapid eye movement (NREM) sleep stages

Practical Significance:
This seminal work establishes the link between High Frequency CPC with good sleep quality, and Low Frequency CPC with poor quality sleep

View Publication:

 

Analysis of cardiopulmonary coupling to assess adaptive servo-ventilation success in complex sleep apnea management.

Authors:
Ramar K, Desrues B, Ramar P, Morgenthaler TI.

Reference:
Sleep Breath. 2013 May;17(2):861-6.

Objectives:
ASV success would correlate with elevated proportions of periodic breathing as marked by elevated narrow band low-frequency cardiopulmonary coupling (eNB-LFC) on cardiopulmonary coupling (CPC) analysis.

Conclusions:
ASV brought AHI to 11.0 ± 13.0, with success in 81.1 % of patients, as defined by an AHI of <10/h. NB-LFC was elevated (>0) in 45.3 %; however, the percentage of eNB-LFC did not correlate with ASV treatment success (p = 0.518). No clinical factors were found to be associated with ASV success.

Practical Significance:
ASV was successful in 81 % of patients with CompSAS. However, eNB-LFC calculated from CPC, a marker for periodic breathing, did not correlate with ASV success and therefore may not be a useful tool to predict ASV success.

View Publication:

 

Applications of evolving technologies in sleep medicine

Authors:
Verbraecken J

Reference:
Breathe, December 2013, Volume 9, No 6

Objectives:
Nocturnal polysomnography (PSG) is the most important laboratory technique in the management of sleep–wake disturbances and is considered the “gold standard” [1]. New sensor technologies are entering the field, and rapid development in telecommunications and mobile technology has accelerated the introduction of telemedicine as a viable and reliable option [2]. The present broad review is an amalgam of the current knowledge with proposed new sensors and remote control. The reader should note that not all of the techniques discussed here have strong clinical validation, and this should be considered when purchasing equipment.

Conclusions:
Traditional sleep monitoring methods use a variety of leads and probes on the patient’s face and body to gather data. Additional information can be achieved from these signals by advanced processing based on complex algorithms. Moreover, a number of signals that are not traditionally used in clinical PSG will become of interest for specific patient categories. We are also faced with the development of innovative noncontact systems based on movement detection using radar and infrared technology. The idea of automatic sleep evaluation and monitoring through signals that are integrated into the environment (a sensorised bed) or through wearable textile technology will change the traditional paradigm of clinical polysomnography. Implementation of wireless applications and remote monitoring will lead to new platforms and evolve towards low-threshold sleep telemedicine. The available evidence base has, however, lagged far behind.

Practical Significance:
Based on the information obtained by electroencephalography, electro-oculography and electromyography (EMG), sleep stages can be defined according to the criteria of Rechtschaffenand Kales [3] and the new American Academy of Sleep Medicine criteria [4]. Ventilation is often measured qualitatively by means of thermistors but is more appropriately measured with nasal pressure cannulae, or by means of a pneumotachograph, connected with a full face mask, or calibrated inductance plethysmography, although calibration of this is difficult [5]. Breathing effort can also be detected by recording movements of the chest and abdomen, surface EMG, snoring, and changes in arterial blood pressure, but most effectively by detection of intrathoracic pressure swings. These swings can be detected by measuring oesophageal pressure. Movements of the chest and abdomen can be recorded with strain gauges (which detect changes in resistance according to length changes), inductance plethysmography or Respitrace (with detection of inductance characteristics of electrical conductors), impedance or even a static charge sensitive bed (which detects respiratory movements). If respiratory effort is detected during an apnoea, this can be explained by occlusion of the upper airways. Oxygen saturation is measured by means of pulse oximetry (SpO2), as well as transcutaneous carbon dioxide tension (PCO2). Sound recording is another method to detect ventilation. Frequency analysis of the sounds (predominantly snoring) can deliver more information on flow limitation. Routinely, body position (position sensor on the chest) is also recorded. The combined application of these measurement techniques allows the assessment of normal and abnormal physiological events in relation to sleep structure [6].

View Publication:

 

Assessment of therapeutic options for mild obstructive sleep apnea using cardiopulmonary coupling measures.

Authors:
Schramm PJ, Thomas RJ

Reference:
J Clin Sleep Med. 2012 Jun 15;8(3):315-20.

Objectives:
To examine the efficacy of various therapeutic modalities for mild obstructive sleep apnea using cardiopulmonary coupling variables of sleep quality.

Conclusions:
Baseline sleep quality estimated using the ratio of high-frequency and low-frequency coupling (1.03) was below the expected normal adult values ranging from 1.67-4.0. The sleep quality ratio was significantly higher (2.08) using the MAA alone compared to baseline, sleep position restriction (1.61), oxygen therapy (0.81), and the combination of MAA with oxygen (1.66).

Practical Significance:
Sleep quality measured objectively using cardiopulmonary coupling variables differentiated the efficacy of therapeutic options for mild obstructive sleep apnea.

View Publication:

 

Bupropion response on sleep quality in patients with depression: implications for increased cardiovascular disease risk.

Authors:
Schramm PJ, Poland RE, Rao U.

Reference:
Eur Neuropsychopharmacol. 2014 Feb; 24(2):207-14.

Objectives:
To evaluate bupropion response in depressed patients by polysomnography (PSG) and cardiopulmonary coupling (CPC) variables.

Conclusions:
Bupropion increased REM latency but did not impact PSG sleep continuity, architecture and CPC variables. A trend was observed towards increasing VLFC duration. Bupropion increased the number of stable-unstable sleep transitions. Moderate to strong correlations between PSG and CPC variables were found on placebo and bupropion nights.

Practical Significance:
Increased stable-unstable sleep transitions and VLFC duration may indicate vulnerability to cardiovascular disease due to their association with low heart rate variability that has been associated with increased mortality raising the question whether the beneficial effects of the antidepressant medication outweighs the impact on cardiopulmonary dynamics.

View Publication:

 

Cardiopulmonary coupling analysis: changes before and after treatment with a mandibular advancement device.

Authors:
Lee WH, Ahn JC, We J, Rhee CS, Lee CH, Yun PY, Yoon IY, Kim JW.

Reference:
Sleep Breath. 2014 Apr 4.

Objectives:
To evaluate the changes of sleep quality in patients using a mandibular advancement device (MAD) for obstructive sleep apnea (OSA) based upon cardiopulmonary coupling (CPC).

Conclusions:
The CPC parameters showed a significant improvement with the use of MAD.

Practical Significance:
CPC parameters of sleep quality was improved by MAD therapy and could be used as a measure of treatment efficacy.

View Publication:

 

Differentiating Obstructive from Central & Complex Sleep Apnea Using an Automated Electrocardiogram-based Method

Authors:
Thomas RJ, Mietus JE, Peng CK, Gilmartin G, Daly RW, Goldberger AL, Gottlie DJ.

Reference:
Sleep. 2007 Dec;30(12):1756-69.

Objectives:
Complex sleep apnea is defined as sleep disordered breathing secondary to simultaneous upper airway obstruction and respiratory control dysfunction. The objective of this study was to assess the utility of an electrocardiogram (ECG) based CPC technique to distinguish obstructive from central or complex sleep apnea

Conclusions:
ECG based spectral analysis allows automated, operator-independent characterization of probable interactions between impaired respiration and upper airway anatomical obstruction. The clinical utility of spectrographic classification, especially in predicting failure of positive airway pressure therapy, remains to be more thoroughly tested

Practical Significance:
Using the Heart Health Study population of 3989 subjects, this study shows that CPC not only differentiated obstructive vs. central vs. complex sleep apnea, but it positively correlated with periodic breathing episodes in PSG and was the strongest predictor of success or failure with PAP titration.

View Publication:

 

ECG-derived Cardiopulmonary Analysis of Pediatric Sleep-Disordered Breathing

Authors:
Guo D, Peng CK, Wu H, L,Mietus JE, Liu Y, Sun RS, Thomas RJ

Reference:
Sleep Medicine 2011;12(4): 384-389

Objectives:
An ECG-derived sleep spectrogram, based on CPC analysis previously described in adults, can provide information about the severity of sleep disordered breathing (SDB) and coupled interactions of sleep modulated autonomic drive and respiration. We hypothesized that CPC algorithm-derived metrics will correlate with nasal pressure-based apnea–hypopnea scoring in pediatric population.

Conclusions:
ECG-derived sleep spectrogram metrics are correlated with nasal flow-derived respiratory abnormality in pediatric SDB. In suitable clinical contexts, this method may have screening utility and possibly allow tracking of treatment effects, specifically in children with severe SDB

Practical Significance:
The high correlation between CPC metrics and nasal flow derived metrics in pediatric SDB patients demonstrates an opportunity to screen for SDB and track treatment effects.

View Publication:

 

Electrocardiogram-Based Sleep Spectrogram Measures of Sleep Stability and Glucose Disposal in Sleep Disordered Breathing

Authors:
Pogach, MD; Naresh M. Punjabi, MD, PhD; Neil Thomas; Robert J. Thomas, MD

Reference:
SLEEP 201235(1):139-148

Objectives:
This analysis explored associations between glucose metabolism and an EEG-independent measure of sleep quality, the sleep spectrogram, which maps coupled oscillations of heart-rate variability and electrocardiogram (ECG)-derived respiration.

Conclusions:
The ECG-spectrogram analysis of sleep quality may provide information beyond that obtained by conventional polysomnography (PSG) in relationship to glucose metabolism

Practical Significance:
Experimental sleep fragmentation can impair insulin sensitivity. ECG-derived sleep-spectrogram measures of sleep quality are associated with alterations in glucose-insulin homeostasis. This could improve our understanding of sleep and sleep-breathing effects on glucose metabolism.

View Publication:

 

Enhancement of sleep stability with Tai Chi exercise in chronic heart failure: preliminary findings using an ECG-based spectrogram method.

Authors:
Yeh GY, Mietus JE, Peng CK, Phillips RS, Davis RB, Wayne PM, Goldberger AL, Thomas RJ.

Reference:
Sleep Med. 2008 Jul;9(5):527-36. Epub 2007 Aug 3.

Objectives:
To assess the effects of a 12-week Tai Chi exercise program on sleep using the sleep spectrogram, a method based on a single channel electrocardiogram (ECG)-derived estimation of cardiopulmonary coupling, previously shown to identify stable and unstable sleep states.

Conclusions:
At 12 weeks, those who participated in Tai Chi showed a significant increase in HFC and significant reduction in LFC, compared to patients in the control group. Correlations were seen between improved sleep stability and better disease-specific quality of life.

Practical Significance:
Tai Chi exercise may enhance sleep stability in patients with chronic heart failure. This sleep effect may have a beneficial impact on blood pressure, arrhythmogenesis and quality of life.

View Publication:

 

Heritability of Abnormalities in in Sleep Apnea: Use of an Electrocardiogram-based Technique

Authors:
Ibrahim LH, Jacono FJ, Patel SR, Thomas RJ, Larkin EK, Mietus JE, Peng CK, Goldberger AL, Redline S

Reference:
SLEEP 2010;33(5):643-646

Objectives:
To evaluate the familial aggregation of distinctive spectrographic biomarkers of unstable sleep, related to elevated-low frequency (e-LFC), and to assess their utility in genetic studies.

Conclusions:
Approximately 30% of the variability of e-LFC, measured from a continuous ECG during sleep is explained by familial factors other than BMI. ECG-based spectrographic measures of heart rate variability & breathing rate may provide novel markers for characterizing subgroups of individuals with different propensities and genetic etiologies for sleep apnea or for other conditions associated with sleep fragmentation.

Practical Significance:
This study suggests that CPC provides an objective measure aimed to enhance our understanding of the genetics of OSA by identifying intermediate traits with high heritability.

View Publication:

 

HHT based cardiopulmonary coupling analysis for sleep apnea detection

Authors:
Dongdong Liu, Xiaochen Yang, Guangfa Wang, Jing Ma, Yanhui Liu, Chung-Kang Peng, Jue Zhang, Jing Fang

Reference:
Sleep Medicine 13(5):503-509, May 2012

Objectives:
To validate the feasibility of the Hilbert–Huang transform (HHT) based cardiopulmonary coupling (CPC) technique in respiratory events detection and estimation of the severity of apnea/hypopnea.

Conclusions:
The HHT-CPC spectrum provides much finer temporal resolution and frequency resolution (8s and 0.001Hz) compared with the original CPC (8.5min and 0.004Hz). The area under the ROC curve of pLFC was 0.79 in distinguishing respiratory events from normal breathing. Significant differences were found in TVDF among groups with different severities of OSAHS (normal, mild, moderate, and severe, p<0.001). TVDF has a strong negative correlation with the apnea/hypopnea index (AHI, correlation coefficient −0.71).

Practical Significance:
The spectrographic markers, pLFC and TVDF can be used to identify respiratory events and represent the disruption extent of sleep architecture in patients with sleep apnea/hypopnea, respectively.

View Publication:

 

Impaired Sleep Quality in Fibromyalgia: Detection and Quantification with ECG-based Cardiopulmonary Coupling Spectrograms

Authors:
Thomas RJ, Mietus JE, Peng CK, Goldberger AL. Crofford LJ, Chervin RD

Reference:
Sleep Med. 2010;11(5): 497-8.

Objectives:
To employ the use of CPC to retrospectively analyze polysomnogram (PSG) ECG data from patients with fibromyalgia compared with matched controls.

Conclusions:
Both ECG and EEG approaches yield consistent findings in this syndrome, further solidifying the hypothesis of altered sleep stability in fibromyalgia.

Practical Significance:
This study shows the favorable comparison of CPC findings over time with traditional PSG findings and the pain diaries of patients suffering from fibromyalgia.

View Publication:

 

Mapping Sleep Using Coupled Biological Oscillations

Authors:
Thomas RJ, Mietus JE

Reference:
Conf. Proc IEEE Eng Med Biol. Soc. 2011;2011:1479-82.

Objectives:
To examine the utility of an electrocardiogram-derived sleep spectrogram to provide a different view of sleep

Conclusions:
Non-electroencephalogram (EEG) recordings can provide an alternative approach to viewing sleep quality.

Practical Significance:
Novel insights into physiology and pathology of sleep can be obtained through the coupling of ECG and respiratory signal influences on the ECG R wave.

View Publication:

 

Measuring sleep quality after adenotonsillectomy in pediatric sleep apnea.

Authors:
Lee SH, Choi JH, Park IH, Lee SH, Kim TH, Lee HM, Park HK, Thomas RJ, Shin C, Yun CH.

Reference:
Laryngoscope. 2012 Sep;122(9):2115-21.

Objectives:
To demonstrate postoperative changes in sleep quality in children with obstructive sleep apnea (OSA), using both conventional sleep staging and electrocardiogram-based cardiopulmonary coupling (CPC) analysis. The hypothesis is that being electroencephalography (EEG)-independent, CPC may detect changes in sleep quality that traditional sleep architecture analysis cannot.

Conclusions:
Adenotonsillectomy led to a significant change in CPC parameters (HFC, LFC), which was paralleled by significant improvements in the apnea-hypopnea and arousal index. Polysomnographic sleep stage parameters other than the arousal index did not reflect postoperative resolution of OSA.

Practical Significance:
In pediatric OSA, postoperative improvement of sleep quality is more readily discernible by CPC analysis than EEG-based sleep staging. The CPC analysis may have potential advantages in the assessment of sleep quality in pediatric populations.

View Publication:

 

On-Call Duty Effects on Sleep-State Physiological Stability in Male Medical Interns

Authors:
Yu-Hsuan Lin, Yen-Cheng Ho, Sheng-Hsuan Lin, Yao-Hsien Yeh, Chia-Yih Liu, Terry B. J. Kuo, Cheryl C. H. Yang, Albert C. Yang

Reference:
PLoS One. 2013 Jun 4;8(6):e65072.

Objectives:
To investigate sleep stability decreased in medical interns during on-call duty.

Conclusions:
The medical interns had significantly reduced stable sleep, and displayed increased latency to the first epoch of stable sleep during the on-call night shift, compared to the pre-call and on-call duty-free nights.

Practical Significance:
The medical interns had significantly reduced stable sleep, and displayed increased latency to the first epoch of stable sleep during the on-call night shift, compared to the pre-call and on-call duty-free nights.

View Publication:

 

Prevalent Hypertension and Stroke in the Sleep Heart Health Study: Association with an ECG-derived Spectrographic Marker of Cardiopulmonary Coupling

Authors:
Thomas RJ, Weiss MD, Mietus JE, Peng CK, Goldberger AL, Gottlieb DJ.

Reference:
SLEEP 2009;32(7):897-904

Objectives:
The ECG-based sleep spectrogram generates a map of CPC based on heart rate variability and respiration derived from QRS amplitude variations. A distinct spectrographic type, designated as elevated Low Frequency Coupling Narrow Band (e-LFCNB), has been associated with central apneas and periodic breathing and predicts failure of CPAP therapy. This study assesses, at a population level, the associations of this spectrographic biomarker with prevalent cardiovascular disease using the Sleep Heart Health Study (SHHS)-I dataset.

Conclusions:
An ECG derived spectrographic marker related to low frequency is associated with greater sleep apnea severity. Whether this biomarker is solely a sign of more severe disease or whether it reflects primary alterations in sleep apnea pathophysiology, which may either cause or result from sleep apnea, is unknown. This ECG-based spectral marker is associated with a higher prevalence of hypertension and stroke.

Practical Significance:
The presence of e-LFCNB represents for the first time a biomarker for sleep disordered breathing independent of age, sex and body mass has been described.

View Publication:

 

Quantitative measurement of sleep quality using cardiopulmonary coupling analysis: a retrospective comparison of individuals with and without primary insomnia.

Authors:
Schramm PJ, Thomas R, Feige B, Spiegelhalder K, Riemann D.

Reference:
Sleep Breath. 2013 May;17(2):713-21.

Objectives:
To determine the utility of a new operator-independent, automated measure of sleep physiology based on cardiopulmonary coupling (CPC) analysis in subjects with primary insomnia vs. good sleepers.

Conclusions:
CPC variables showed a significant multivariate analysis of variance group, night, and group × night main effect, except for HFC by night. Relative to good sleepers, primary insomnia patients on adaptation night had lower HFC, a putative biomarker of stable sleep, and HFC/LFC ratio, an indicator of sleep quality. The primary insomnia group also had higher LFC, an index of unstable sleep, and an increase in VLFC and e-LFC compared to good sleepers on adaptation night. On baseline night, the primary insomnia group had increased LFC, VLFC, and e-LFC and a lower HFC/LFC ratio. Except for HFC, good sleepers had larger CPC variable differences between adaptation and baseline nights compared to the primary insomnia group.

Practical Significance:
Primary insomnia subjects have a marked worsening of sleep quality on the adaptation night, which is well captured by both conventional and ECG-derived sleep spectrogram techniques. The larger improvement of sleep quality was found among good sleepers and captured only by CPC analysis. The operator-independent, automated measure of sleep physiology demonstrated functionality to differentiate and objectively quantify sleep quality.

View Publication:

 

Relationship between delta power and the electrocardiogram-derived cardiopulmonary spectrogram: possible implications for assessing the effectiveness of sleep.

Authors:
Thomas RJ, Mietus JE, Peng CK2, Guo D, Gozal D, Montgomery-Downs H, Gottlieb DJ, Wang CY, Goldberger AL.

Reference:
Sleep Med. 2014 Jan; 15(1):125-31.

Objectives:
To evaluate the hypothesis that that slow-wave EEG power would show a relatively fixed-time relationship to periods of high-frequency CPC.

Conclusions:
The overall correlation (r) between delta power and high-frequency coupling (HFC) power was statistically significant.

Practical Significance:
The results support a tight temporal relationship between EEG slow wave power and high frequency cardiopulmonary coupling.

View Publication:

 

Sleep Quality among Female Hospital Staff Nurses

Authors:
Chien PL, Su HF, Hsieh PC, Siao RY, Ling PY, Jou HJ.

Reference:
Sleep Disord. 2013; 2013: 283490.

Objectives:
To investigate sleep quality of hospital staff nurses, both by subjective questionnaire and objective measures.

Conclusions:
Among the staff nurses, 75.8% (117) had a PSQI score of ≥5 and 39.8% had an inadequate stable sleep ratio.

Practical Significance:
Both subjective and objective measures demonstrated that poor sleep quality is a common health problem among hospital staff nurses.

View Publication:

 

Sleep quality change after upper airway surgery in obstructive sleep apnea: Electrocardiogram-based cardiopulmonary coupling analysis

Authors:
Choi JH1, Thomas RJ, Suh SY, Park IH, Kim TH, Lee SH, Lee HM, Yun CH, Lee SH.

Reference:
Laryngoscope. 2015 Feb 3. doi: 10.1002/lary.25101.

Objectives:
Sleep quality change after upper airway surgery in obstructive sleep apnea: Electrocardiogram-based cardiopulmonary coupling analysis

Conclusions:
Successful upper airway surgery can improve objective sleep quality in adult patients with OSA. CPC metrics of sleep quality are potentially useful to monitor therapeutic responses during long-term postoperative follow-up, as the ECG-based analysis is available as a standalone option outside laboratory polysomnography.

Practical Significance:
Sleep quality measured by CPC analysis improved significantly (HFC, P = .001; LFC, P = .002; e-LFC, P = .003), along with parallel reduction in ESS, respiratory parameters (AHI, AI, minimum SaO2), and sleep fragmentation (ArI) in the group with surgical success after upper airway surgery.

View Publication:

 

Sleep Quality Changes in chronically depressed patients treated with mindfulness-based cognitive therapy or cognitive behavioral analysis system for psychotherapy: a pilot study

Authors:
Schramm P.J., Zobel I., Mönch K., Schramm E., Michalak J.

Reference:
Sleep Medicine 17 (2016) 57–63

Objectives:
To measure sleep quality changes in response to group psychotherapy for chronic depression.

Conclusions:
Physician-referred, chronically depressed patients (n = 25) were randomized to either eight group sessions of Mindfulness-based Cognitive Therapy (MBCT, n = 9) plus Treatment As Usual (TAU), or the Cognitive Behavioral Analysis System of Psychotherapy (CBASP, n = 8) plus TAU, or to TAU only (control group, n = 8). Participants recorded their sleep at home.

The primary outcome variables were: stable and unstable sleep, which were assessed using cardiopulmonary coupling (CPC) analysis, and estimated total sleep and wake time (minutes). Cardiopulmonary coupling measures heart rate variability and the electrocardiogram's R-wave amplitude fluctuations associated with respiration.

By post-treatment night 6, the CBASP group had more stable sleep (p = 0.044) and less wake (p = 0.004) compared with TAU, and less wake vs MBCT (p = 0.039).

Practical Significance:
The CBASP group psychotherapy treatment improved sleep quality compared with Treatment As Usual.

View Publication:

 

Sleep State Instabilities in Major Depressive Disorder: Detection and Quantification with Electrocardiogram-based Cardiopulmonary Coupling Analysis

Authors:
Yang AC, Yang CH, Hong CJ, Tsai SJ, Kuo CH, Peng CK, Mietus JE, Goldberger AL, Thomas RJ.

Reference:
Psycho-physiology. 2011:48(2):285-291

Objectives:
To evaluate the utility of electrocardiogram (ECG)-based analysis to quantify physiologic sleep stability in patients with major depression

Conclusions:
Relative to controls, non-medicated depressed patients had a reduction in High-Frequency Coupling (HFC; index of stable sleep), an increase in Low Frequency Coupling (LFC; index of unstable sleep), and an increase in very Low Frequency Coupling (vLFC; index of wakefulness/REM sleep).

Practical Significance:
ECG-based analysis can offer a simple, cost-efficient point-of-care method to quantify sleep quality/stability and to objectively evaluate the severity of insomnia in patients with major depression.

View Publication:

 

Technical advances in the characterization of the complexity of sleep and sleep disorders.

Authors:
Bianchi MT, Thomas RJ.

Reference:
Prog Neuropsychopharmacol Biol Psychiatry. 2013 Aug 1;45:277-86.

Objectives:
A review of the spectrum of approaches that have been leveraged towards improved understanding of the complexity of sleep.

Conclusions:
The complexity of sleep physiology has inspired alternative metrics that are providing additional insights into the rich dynamics of sleep. Electro-encephalography, magneto-encephalography, and functional magnetic resonance imaging represent advanced imaging modalities for understanding brain dynamics.

Practical Significance:
These methods are complemented by autonomic measurements that provide additional important insights.

View Publication:

 

The association between leukocyte telomere lengths and sleep instability based on cardiopulmonary coupling analysis

Authors:
Kwon AM1, Baik I, Thomas RJ, Shin C.

Reference:
Sleep Breath. 2015 Jan 28.

Objectives:
The purpose of the study is to examine the objective association between sleep stability and leukocyte telomere lengths (LTL) using cardiopulmonary coupling (CPC) analysis, which is an electrocardiogram (ECG)-based technique to quantify physiologic sleep stability.

Conclusions:
The present study suggested that shorter LTL might contribute to reduced sleep stability by interacting with OSA severity due to the stress of chronic sleep fragmentation or invariant sympathetic activity by respiratory chemoreflex activation.

Practical Significance:
LTL showed a significant association with elevated narrow-band low frequency coupling (e-LFCNB, a CPC marker of periodic breathing or sleep fragmentation due to pathological respiratory chemoreflex activation) by interacting with obstructive sleep apnea (OSA) severity (p value of <0.0001). Especially, sleep stability significantly reduced with shortened LTL in OSA patients (Apnea-Hypopnea Index (AHI) ≥15) based on increased e-LFCNB which had a negative correlation with high-frequency coupling band (HFC), a marker of stable sleep.

View Publication:

 

The effect of continuous positive airway pressure on cardiopulmonary coupling.

Authors:
Cho, J.H. & Kim, H.J.

Reference:
Sleep Breath. 2017 May;21(2):341-345. doi: 10.1007/s11325-016-1419-8. Epub 2016 Oct 8.

Objectives:
The aim of the study was to investigate cardiopulmonary coupling (CPC) as a tool for evaluating the efficacy of continuous positive airway pressure (CPAP) in the treatment of obstructive sleep apnea (OSA).

Conclusions:
The apnea-hypopnea index, CPC variables, and sleep stage (%) during the first 2 h of the sleep study did not differ between the PSG-only and CPAP titration groups. A comparison of data collected over the first 2 h and that collected over the rest of the sleep study revealed that high-frequency coupling (HFC) increased, and low-frequency coupling (LFC) and elevated LFC (e-LFC) decreased only for the CPAP titration group, while they did not change for the PSG-only group. The proportions of N1 and N3 stages and arousal index decreased while the proportion of R stage increased for both groups. The proportion of N2 stage and mean O2saturation increased only for the CPAP titration group, while they did not change significantly for the PSG-only group. HFC increased while LFC and e-LFC decreased linearly as apnea-hypopnea index decreased for the CPAP titration group.

Practical Significance:
CPC effectively reflects the treatment effect of CPAP when compared with an electroencephalography-based sleep stage assessment.

View Publication:

 

The Sleep Quality Recovery of a Snorer's Bed Partner

Authors:
Schramm PJ, Neville AN, Baker D

Reference:
Respiratory Therapy Vol. 5 No. 3 June-July 2010 pg. 39

Objectives:
To demonstrate, through the use of CPC technology, the negative impact of snoring and Obstructive Sleep Apnea (OSA) and the response to PAP initiation the bed partner’s sleep quality.

Conclusions:
Both the snorer and his bed partner’s sleep quality improved significantly with the application of PAP therapy.

Practical Significance:
Proof to a reticent CPAP user of the benefit of CPAP compliance to their bed partner as well as themselves

View Publication:

 

Wearable Sleep Epidemiology In The Framingham Heart Study

Authors:
EJ Heckman, R Salazar, S Hardy, E Manders, Y Liu, R Au, G O’Connor, R Thomas

Reference:
Sleep, Volume 40, Issue suppl_1, 28 April 2017, Pages A289

Objectives:
Wearable devices for sleep assessments offer a cost-effective and convenient alternative to traditional measures of sleep. Devices are now available to measure oxygenation, respiration electrocardiogram, and electroencephalogram in the home environment. This study assessed standard (oximetry) and novel (cardiopulmonary coupling) measures of sleep state in a well-established epidemiology cohort.

Conclusions:
The results suggest that home/wearable assessment of sleep is 1) feasible, cost-effective, and yields reliable results; 2) inter-individual differences are stable; 3) measures can be readily repeated; 4) in-person visits are not required, markedly simplifying data collection. Both standard and novel measures can be collected.

Practical Significance:
A total of 972 participants agreed to participate. 126 participants were unable or refused to complete the study. 830 and 836 participants obtained at least 4 hours of data with the M1 and oximetry device for at least one night, respectively. 574 participants wore both devices for 2 consecutive nights (803 wore M1, 695 wore Ox for 2 consecutive nights). The mean (SD) were as follows: HFC 43.5%(18.8), LFC 37.28%(17.03), ODI 8.3(8.5), oxygen saturation below 90% 48.1(77.24) minutes, and 52.5% of the sample had narrow band coupling. The ICC for these variables ranged from 74.5%-99.9%, suggesting high night to night data and physiological signal stability. Associations with common medical co-morbidities will be presented.

View Publication: