Papers by Gerhard Kloesch
Sleep medicine, Feb 1, 2024
Neuropsychobiology, 2010
Access to full text and tables of contents, including tentative ones for forthcoming issues: www.... more Access to full text and tables of contents, including tentative ones for forthcoming issues: www.karger.com/nps_issues
Sleep, Apr 1, 2019
Supplement, 2019 (LOG) or artificial neural network (ANN) and validated their performance in an i... more Supplement, 2019 (LOG) or artificial neural network (ANN) and validated their performance in an international clinical sample and in a community-based sample. Methods: Retrospective data on 17,448 subjects who underwent polysomnography in five international sleep centers within the Sleep Apnea Global Interdisciplinary Consortium were allocated into training (n=10,469) and validation sets (n=6,979). Two models to predict the presence of OSA (Apnea Hypopnea Index ≥15 events/hour) were developed from the training set based on probabilities derived from LOG and ANN using age, gender, BMI, and ethnicity. Model performance was evaluated using the area under the curve (AUC), positive (PPV) and negative predictive values (NPV), sensitivity and specificity, and positive (+LR) and negative likelihood ratios (-LR). The predictive models were validated in the clinical sample and in the Sleep Heart Heath Study (SHHS) community-based sample (n=5,761).
Sleep, Feb 1, 2009
FOR APPROXIMATELY 40 YEARS THE ONLY WIDELY ACCEPTED STANDARD FOR DESCRIBING THE HUMAN SLEEP PROCE... more FOR APPROXIMATELY 40 YEARS THE ONLY WIDELY ACCEPTED STANDARD FOR DESCRIBING THE HUMAN SLEEP PROCESS WAS THE MANUAL OF SLEEP CLASSIFICATION by Rechtschaffen and Kales. 1 On the basis of these scoring rules, sleep recordings are divided into 7 discrete stages (wake, stage 1, stage 2, stage 3, stage 4, stage REM, and movement time). Even though in many cases this standard is useful, the rules of Rechtschaffen and Kales have also been criticized for leaving plenty of room for subjective interpretation, which leads to a great variability in the visual evaluation of sleep stages. 2,3 Last but not least, the standard rules were developed for young healthy adults 4,5 and do not necessarily directly apply to elderly subjects and patients. The American Academy of Sleep Medicine (AASM) 6 modified the standard guidelines for sleep classification by Rechtschaffen and Kales and developed a new guideline for terminology, recording method, and scoring rules for sleep-related phenomena. The manual is the result of a review of literature, analysis and consensus which addresses 7 topics: digital analysis and reporting parameters, visual scoring, arousal, cardiac and respiratory events, movements and pediatric scoring. One of the major changes is a change in terminology: in the AASM classification, sleep stages S1 to S4 are referred to as N1, N2, and N3, with N3 reflecting slow wave sleep (SWS, R&K stages S3 + S4); stage REM is referred to as stage R. According to the AASM manual, a minimum of 3 EEG derivations, sampling activity from the frontal, central, and occipital regions, has to be recorded. The recommended derivations are F4-M1, C4-M1, and O2-M1 (right-sided active electrodes and a reference over the left mastoid, rather than the ear). 7 The new manual also deals with the definition of the sleep-wake transition, sleep spindles, K-complexes, slow wave sleep, and REM sleep, as well as arousals and major body movements. In summary, the major changes of the new manual comprise EEG derivations, the merging of stages 3 and 4 into N3, the abolition of stage "movement time," the simplification of many context rules as well as the recommendation of sampling rates and filter settings for polysomnographic (PSG) reporting and for user interfaces of computer-assisted sleep analysis. 6 To date there are no studies evaluating the effects of the new standard on sleep scoring data. The aim of the present investigation was to describe in detail differences between visual sleep scoring according to the Rechtschaffen and Kales classification and scoring based on the new AASM guidelines in normal subjects of different age groups and sleep-disturbed patients.
Journal of Sleep Research, Sep 1, 2006
ABSTRACT 15
Asia-Pacific Signal and Information Processing Association Annual Summit and Conference, Dec 7, 2020
A contactless system to detect respiratory events during sleep may be advantageous because it ena... more A contactless system to detect respiratory events during sleep may be advantageous because it enables normal sleeping pattern and eliminates the need for constant monitoring of contact sensors. To detect sleep respiratory events, a 3D timeof-flight (TOF) camera is placed above the bed to measure a respiratory movement signal. Using this signal, we trained a long-short term memory (LSTM) model to detect respiratory events. In addition, we trained LSTM models based on SpO2, and abdomen and thorax respiratory inductance plethysmography (RIPsum). LSTM models were trained on 8 folds using 61 synchronized 3D video and polysomnography (PSG) recordings of patients with suspected sleep apnea to classify 30-second segments as either respiratory event or normal breathing. Manual PSG annotations served as ground truth. The LSTM model based on 3D TOF camera achieved a mean accuracy of 0.79 and mean Cohen's kappa of 0.54. SpO2 based model scored a mean accuracy of 0.86 and mean Cohen's kappa of 0.68 while RIPsum based model scored a mean accuracy of 0.82 and mean Cohen's kappa of 0.61. The 3DRespMvt performance can be improved by combining it with SpO2, resulting in a mean accuracy of 0.87 and mean Cohen's kappa of 0.71. I.
Journal of Sleep Research, Sep 1, 2006
Journal of Sleep Research, Sep 1, 2006
IFMBE proceedings, Jun 13, 2017
Respiratory effort is a major feature for detection and classification of apneas in polysomnograp... more Respiratory effort is a major feature for detection and classification of apneas in polysomnography. Presently, somnologists apply flow sensors and/or rip belts at the thorax and abdomen for this purpose, causing practical problems with the montage and re-adjustment during the night and disturbing patients´ sleep. Contactless measurements would be a desirable alternative. We utilized a 3D time-of-flight camera to monitor respiratory-related chest movements to decipher epochs of normal breathing and apnea. Time-synchronized comparisons of 3D measurements of chest movements due to respiration to signals from rip belts and nasal airflow proved that the 3D sensor provided equivalent results. This new technique could support the diagnosis of sleep apnea and Cheyne-Stokes breathing. It simplifies the procedure, saves personnel capacity, improves data quality and releases the burden to the patient by replacing body-mounted sensors and cabling.
Current Directions in Biomedical Engineering, Sep 1, 2017
In polysomnography, an oronasal thermal airflow sensor and respiratory inductance plethysmography... more In polysomnography, an oronasal thermal airflow sensor and respiratory inductance plethysmography (RIP) belts at thorax and abdomen are used to detect central sleep apnoea. These sensors are uncomfortable to wear, can disturb the patient´s sleep, and data quality can be significantly diminished if a sensor slips off the patient. Contactless measurements would be a desirable alternative. We utilized a 3D time-of-flight sensor to monitor respiratory-related chest movements to decipher epochs of normal breathing and apnoea in ten adult patients with a total of 467 apnoea events. Time-synchronized comparisons of 3D measurements of chest movements due to respiration to polysomnography signals from rip belts and nasal airflow proved that the 3D sensor provided largely equivalent results. This new technique could support the diagnosis of central sleep apnoea and Cheyne-Stokes respiration.
Sleep and Biological Rhythms, Oct 1, 2007
Couples sleeping in pairs is a modern phenomenon with potential side-effects on sleep structure a... more Couples sleeping in pairs is a modern phenomenon with potential side-effects on sleep structure and circadian rhythms. In order to examine its effects, 10 healthy heterosexual couples with stable relationships who regularly sleep apart or together in their home environments were recruited. The participants were asked to spend at least 10 nights alone and 10 nights together over the course of the study. Their sleep was monitored over 28 days in their homes with actigraphic techniques and sleep diaries. Group analyses were performed on their sleep efficiency and subjective sleep quality according to sleep condition. The daily variations in sleep fragmentation indices of the partners were used as a measure of their nocturnal activity synchronization. Sharing a sleeping space with a partner had negative effects on sleep in women, as documented in the actigraphic measurements of sleep efficiency and subjective assessments of sleep and awakening quality. Sexual contact mitigated the negative subjective report, without changing the objective results. Subjective assessments of sleep quality were lower in men than women when sleeping alone. They increased to the same level as women while sleeping in pairs with or without sexual contact. The sleep efficiency in men was not reduced by the presence of their partner unless sexual contact occurred. Analyses of sleep fragmentation showed that there was no synchronization of deviation from the norm levels between the partners on individual nights either when they slept alone or in couples. The sex differences in the nocturnal sleep reactions to partner presence may be attributed to sex-specific behavioral traits associated with cultural norms or parenting in women and the desire for group sleep in men.
European Psychiatry, Mar 1, 2011
Objectives: Experience-dependent cortical plasticity observed during post-training sleep has been... more Objectives: Experience-dependent cortical plasticity observed during post-training sleep has been hypothesized to be part of the global process of memory consolidation. Combining the temporal resolution of microstructure detectors and the spatial resolution of low-resolution brain electromagnetic tomography (LORETA) makes it possible to investigate when and where the experience-dependent reactivation occurs under normal (undisturbed) sleeping conditions.
Klinische Neurophysiologie, Mar 1, 2007
Fragestellung: In der aktuellen Literatur wird nach wie vor diskutiert, ob und auf welche Art und... more Fragestellung: In der aktuellen Literatur wird nach wie vor diskutiert, ob und auf welche Art und Weise Gedachtniskonsolidierung von Schlaf profitieren konnte. Das Ziel der vorliegenden Studie lag darin, den Zusammenhang zwischen EEG Theta-Aktivitat (i) wahrend dem Lernen einer deklarativen Wortpaar-Assoziationsaufgabe sowie (ii) wahrend dem darauf folgenden REM-Schlaf und allgemeiner Gedachtnisleistung aufzuzeigen. Methoden: 24 Probanden (Alter: 19–30 Jahre) bewaltigten eine deklarative Lernaufgabe, bestehend aus 160 visuell prasentierten Wortpaaren und wurden unmittelbar nach dem Lernen („Encoding“) sowie nach einer Nacht im Schlaflabor inkl. Polysomnographie getestet („cued recall“). Anhand eines Mediansplits wurden die Probanden in zwei Leistungsgruppen (gute vs. schlechte allgemeine Gedachtnisleistung) unterteilt. Ergebnisse: Quantitative EEG Analysen zeigten, dass jene Probanden die eine allgemein gute Gedachtnisleistung aufweisen, sowohl wahrend der Lernphase, als auch wahrend dem darauf folgenden REM-Schlaf okzipital starkere Theta-Synchronisation aufweisen. Schlussfolgerungen: Dass Theta Oszillationen selektiv an der Einspeicherung bzw. dem Abruf – insbesondere von expliziten Gedachtnisspuren – beteiligt sind, konnte bereits gut belegt werden (z.B. Klimesch, 2001). Nach Buzsaki (z.B. 1996) basiert Gedachtniskonsolidierung auf hippokampalen-neokortikalen Interaktionen die insbesondere wahrend ruhigem Wachzustand oder Schlaf auftreten. Dabei werden von Buzsaki zwei Phasen postuliert: (i) „loading“ des Hippokampus wahrend REM-Schlaf und Wachheit sowie (ii) „storing“ wahrend Slow-Wave-Schlaf. In der ersten Phase werden spezifische Gedachtnisinhalte durch den Hippokampus enkodiert, um anschliesend – in der zweiten Phase – zum Neokortex weitergeleitet zu werden. Da angenommen wird, dass Theta-Oszillationen fur den Informationsfluss zwischen Neokortex und Hippokampus von groser Bedeutung sind, lassen die Ergebnisse der prasentierten Studie darauf schliesen, dass die starkere okzipitale Theta-Synchronisation sowohl wahrend der Einspeicherung neuer deklarativer Inhalte, als auch wahrend darauf folgenden REM-Schlaf-Phasen der Gedachtniskonsolidierung zu gute kommen und insgesamt das Gedachtnis starken konnten. Diese Studie wurde vom osterreichischen Wissenschaftsfonds unterstutzt (FWF, P-15370).
Sleep, Apr 1, 2018
Methods: All participants underwent a polysomnogram (PSG). The apnea hypopnea index (AHI), total ... more Methods: All participants underwent a polysomnogram (PSG). The apnea hypopnea index (AHI), total sleep time (TST), Sleep Efficiency (SE), Sleep Onset Latency (SOL), arousals and PLM Index (PLMI) were computed. Results: Of all subjects, 19.7% of the participants had PLMI ≥ 10/hour, 14.8% had PLMI ≥ 15/hour, 12.1% had PLMI ≥ 20/hour and 7.5% had PLMI ≥ 30/hour. The 75 th percentile PLMI was 5.5, 80th percentile was 9.3, 90th percentile was 24.1 and 95th percentile was 37.2/hour. PLMI was associated positively with SOL (R=.075, P=0.01) and inversely with SE (R=-.113, P=<0.001) and TST (R=-.106, P=<0.001). Linear regression models showed that the association between PLMI and sleep variables was independent of AHI and depression (HAMD score). There was no significant correlation between PLMI and AHI, Epworth Sleepiness Scale scores or Maintenance of Wakefulness Test sleep latency. No correlation was seen between PLMI and Hamilton Depression Rating Scale (HAMD) or Sleep Apnea Quality of Life Index (SAQLI) scores. A linear regression model showed increasing age (Beta=.19, P<0.01) and total caffeine servings per week (Beta=.09, P=0.02) to be independent predictors of PLMI. A logistic regression model showed higher odds of PLMI ≥ 10 with older age (OR=1.03, P<0.001), male gender (OR=1.63, P=0.01), antidepressant use (OR=1.48, P=0.048), and caffeine servings per week (OR=1.
Die vorliegende Studie befasst sich mit dem Thema Muedigkeit am Steuer. In einer Vorphase wurde m... more Die vorliegende Studie befasst sich mit dem Thema Muedigkeit am Steuer. In einer Vorphase wurde mittels Literaturrecherche festgehalten, welche Erkenntnisse zum Thema bereits bestehen und welche theoretischen Vorueberlegungen zur Studie getroffen werden koennen. Schaetzungen ueber die tatsaechliche Groessenordnung variieren betraechtlich. Laut Unfalldaten des Bundesministeriums fuer Inneres (BMI) wurden im Jahr 2010 in Oesterreich 5 Prozent aller toedlichen Verkehrsunfaelle vermutlich durch Uebermuedung ausgeloest. Eine Studie des Kuratoriums fuer Verkehrssicherheit schaetzt, dass ca. 8 Prozent aller toedlichen Unfaelle in Oesterreich auf Sekundenschlaf bzw. Uebermuedung zurueckzufuehren sind. In einer empirischen Phase wurden Erhebungen zum Thema Muedigkeit an 4 oesterreichischen Autobahnrastplaetzen durchgefuehrt. Die computerisierten Testungen und Befragungen fanden im Juli und August 2012 an insgesamt 16 Erhebungstagen, vorwiegend am Wochenende, statt. An der Erhebung nahmen 361 Personen im Alter von 17 bis 86 Jahren teil, drei Viertel davon waren Maenner. Bei einem Grossteil der Fahrten (85 Prozent) handelte es sich um private Fahrten. 62 Prozent waren Urlaubsfahrten. Knapp die Haelfte aller Befragten (43 Prozent) gab an, keinen FahrerInnenwechsel zu planen; hinsichtlich der Gesamtstrecke der aktuellen Fahrt gab es grosse Unterschiede bei einem Durchschnittswert von 594 km. Im Durchschnitt gaben die Befragten an, alle 2 Stunden eine Pause einzulegen. Die Antworten auf die Frage, welche Strategien eingesetzt wuerden um sich wachzuhalten, wurden mit jeweils 73 Prozent „Musik hoeren“ und „die Klimaanlage einschalten“ angefuehrt. Als weitere Strategien wurden u.a. „mit Mitfahrenden sprechen“ (59 Prozent) und „das Fenster oeffnen“ (52 Prozent) genannt. Nur ein Drittel gab an, eine Pause zu machen, um sich wach zu halten, nur 10 Prozent nannten den „Konsum koffeinhaltiger Getraenke“. Die gewonnenen Daten wurden analysiert und verschiedene Risikogruppen definiert. In einer Ergebnissicherungsphase wurden auf Basis der vorhergehenden Phasen Empfehlungen fuer bewusstseinsbildende Massnahmen bezueglich Muedigkeit am Steuer abgeleitet, ein Endbericht sowie Informationsfolder wurden erstellt.
Zeitschrift fuer Verkehrsrecht, Jul 1, 2014
Das Projekt „TAKE A REST" befasste sich mit dem Thema Muedigkeit am Steuer und wurde von KFV... more Das Projekt „TAKE A REST" befasste sich mit dem Thema Muedigkeit am Steuer und wurde von KFV (Kuratorium fuer Verkehrssicherheit), OeAMTC und dem Institut fuer Schlaf- und Wachforschung (ISWF) durchgefuehrt. Im Projekt wurden bereits bestehende Erkenntnisse zu diesem Thema zusammengetragen und auf Basis der Rechercheergebnisse eine empirische Studie konzipiert. An oesterreichischen Autobahnraststaetten wurden im Sommer 2012 Lenker mittels Fragebogen gezielt zu diesem Thema befragt und die Auswirkungen von langen Fahrten und monotonen Fahrsituationen auf die Reaktionsfaehigkeit mit Leistungstests untersucht. Durch die Analyse der gewonnenen Daten konnten Risikogruppen definiert und Empfehlungen fuer bewusstseinsbildende Massnahmen bezueglich Muedigkeit am Steuer abgeleitet werden. Als Ergebnis wurde ein Informationsfolder zur Bewusstseinsbildung erstellt.
Journal of Sleep Research, Dec 1, 2008
Sleep Medicine, Dec 1, 2017
Sleep Medicine, Dec 1, 2017
statistically significantly higher risk of having an ESS 10 (adjusted [a] OR 1.59; 95% CI 1.01, 2... more statistically significantly higher risk of having an ESS 10 (adjusted [a] OR 1.59; 95% CI 1.01, 2.51; p-value 0.04). The associations between this outcome and total glucose or fructose were stronger (aOR per-tertile of intake 1.50; 95% CI 1.12, 2.01; p-value 0.006; and aOR 1.46; 95% CI 1.10; 1.193; p-value 0.009; respectively). Higher intakes of starch and of breakfast cereals were associated with less severe OSA (aOR, 0.72; 95% CI 0.53, 0.97; p-value 0.03; and aOR 0.76; 95% CI 0.59, 0.97; p-value 0.03; respectively). There was no evidence of association between measures of AHI and intake of CHOs. Conclusions: Daytime sleep disturbances in middle-aged adults are highly prevalent. To our knowledge, this is the first population-based study to show that dietary CHOs, particularly refined sugars, were associated with a higher prevalence of symptoms related to daytime sleepiness. Improving the quality of CHO content in the diet might reduce the prevalence of these symptoms.
Sleep Medicine, Dec 1, 2015
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Papers by Gerhard Kloesch