Showing papers by "Mathias Basner published in 2008"

Autonomic arousals related to traffic noise during sleep.

Abstract: TRANSIENT EXCITATIONS OF THE CENTRAL AND OF THE AUTONOMIC NERVOUS SYSTEM WITH A COMMON ORIGIN IN THE BRAINSTEM OCCUR FREQUENTLY and spontaneously (with no obvious reason) during normal sleep. Cortical arousals, which might lead to sleep stage changes or awakenings, are usually accompanied by autonomic arousals. As the reverse is not true, the latter may occur alone.1,2 Autonomic arousals are transient elevations of the sympathetic tone. They encompass increases of ventilation, of systolic and diastolic blood pressure, and of peripheral resistance; but they but are most often indicated by alterations of heart rate (HR). These cardiac arousals start to increase well before the visually detectable onset of cortical arousals.1–3 Their extent and patterns vary with the duration of the cortical arousals. With cortical arousals lasting up to 10 s, cardiac arousals are typically biphasic: an initial acceleration is followed by a deceleration below the baseline. The baseline is then regained after a gradual increase 15–30 s after stimulus onset.1,3–5 With longer lasting arousals the deceleration becomes gradually flatter, thus leading to a monophasic elevation of heart rate.1,4–5 Similar alterations are evoked by various external stimuli, in particular by acoustic stimuli.6–8 Research in this area was usually performed with artificial sounds, mostly with tones of up to 4 kHz and durations up to 5 s.6–12 The extents and the patterns of these responses were analyzed in detail and were shown to depend at least on stimulus intensity and on the sleep stage at the time of stimulation. Traffic noises are a major cause of extrinsic sleep disturbances with after effects on mood, performance, and health.13 Despite this, cardiac responses to traffic noise have only occasionally been studied.14–17 A detailed analysis of these responses was performed only for sonic booms, which evoked the typical biphasic cardiac arousals described above.18 This paper deals with the cardiac responses of 24 persons to noises from aircraft, rail, and road vehicles during sleep in the laboratory. It investigates possible influences of acoustical parameters, time of night and momentary sleep stage. Such an analysis is highly relevant as numerous residents living in the vicinity of airports, along busy streets, and along railway tracks are permanently exposed to these noises while sleeping. Long-term exposure to these noises is assumed to contribute to the genesis of cardiovascular diseases.19

Effects of Night Work, Sleep Loss and Time on Task on Simulated Threat Detection Performance

Abstract: STUDY OBJECTIVES: To investigate the effects of night work and sleep loss on a simulated luggage screening task (SLST) that mimicked the x-ray system used by airport luggage screeners. DESIGN: We developed more than 5,800 unique simulated x-ray images of luggage organized into 31 stimulus sets of 200 bags each. 25% of each set contained either a gun or a knife with low or high target difficulty. The 200-bag stimuli sets were then run on software that simulates an x-ray screening system (SLST). Signal detection analysis was used to obtain measures of hit rate (HR), false alarm rate (FAR), threat detection accuracy (A'), and response bias (B"(D)). SETTING: Experimental laboratory study PARTICIPANTS: 24 healthy nonprofessional volunteers (13 women, mean age +/- SD = 29.9 +/- 6.5 years). INTERVENTIONS: Subjects performed the SLST every 2 h during a 5-day period that included a 35 h period of wakefulness that extended to night work and then another day work period after the night without sleep. RESULTS: Threat detection accuracy A' decreased significantly (P Language: en

Event-related awakenings caused by nocturnal transportation noise.

Abstract: The present study focussed on awakenings caused by nocturnal noises emitted from aircraft, road and rail vehicles with maximum levels ranging from 40 to 76 dBA. A laboratory study with 24 participants (12 male, 12 female, 19-28 years) was performed with polysomnographic recordings during 13 nights (including a preceding habituation night). Multivariable random subject effect logistic regression models containing acoustical, situational and individual parameters were used to determine the probability of event-related awakenings for each traffic mode. Awakening probability increased significantly with maximum sound pressure level (SPL), slope of rise (dB/s), noise duration and the noise-free interval between noise events. Gender, noise sensitivity and age did not influence awakening probability significantly (the latter only in a combined model). Awakening probability increased with elapsed time after sleep onset, and was significantly lower during slow wave sleep compared to S2 sleep, but not during REM sleep. After adjusting for differences in study design (acoustical macrostructure), awakening probability decreased in the order rail, road and air traffic noise, but only rail and air traffic noise differed significantly (p= 0.002). After further adjusting for slope of rise and noise duration (acoustical microstructure), differences between traffic modes decreased, but rail and air traffic noise still differed significantly (p=0.044). Acoustical properties other than slope of rise and noise duration may account for the residual difference. The results of this study suggest that the reduction of maximum SPLs, rise slopes, and traffic volume during the second part of the night might reduce the number of noise-induced awakenings.

Nocturnal aircraft noise exposure increases objectively assessed daytime sleepiness

Abstract: There is no doubt that noise in general and aircraft noise specifically disturb sleep. However, so far no study has objectively assessed the effects of traffic noise on daytime sleepiness. In a polysomnographic laboratory study, 24 subjects (mean ± SD age 33.9 ± 10.8 years, 12 male) were investigated between 7:30 am and 8:30 am with infrared pupillography after a noise-free baseline night and after 9 nights with varying degrees of aircraft noise exposure. The natural logarithm of the pupillary unrest index (lnPUI) differed significantly (p = 0.006) between noise (lnPUI = 1.61) and baseline (lnPUI = 1.48) nights. Objective sleepiness levels increased significantly with the number of noise events (p = 0.021), with the maximum sound level of noise events (p = 0.028), and with the equivalent continuous noise level (p = 0.013) in exposure nights. However, these levels did not reach pathological levels as observed in another study on untreated obstructive sleep apnea patients. This is the first study to show that nocturnal aircraft noise exposure increases objectively assessed sleepiness in the next morning. These findings stress the relevance and the potential public health impact of sleep disturbances induced by environmental noise. Further studies are needed to investigate the association of nocturnal traffic noise exposure and objectively assessed sleepiness in the field.

Inter-rater agreement in sleep stage classification between centers with different backgrounds

Abstract: Question of the study To investigate inter-rater agree- ment between scorers from three centers with clinical (Marburg University, UMA) or research (German Aerospace Center, DLR and Dortmund University, UDO) backgrounds. Additionally, sleep scoring rules of the new AASM manual for the scoring of sleep and associated events were reviewed regarding possible implications for inter-rater agreement.

Aircraft noise effects on sleep: a systematic comparison of EEG awakenings and automatically detected cardiac activations.

Abstract: OBJECTIVES: Polysomnography is the gold standard for investigating noise effects on sleep, but data collection and analysis are sumptuous and expensive. We recently developed an automatic algorithm for the identification of cardiac activations associated with cortical arousals, which uses heart rate information derived from a single electrocardiogram (ECG) channel (Basner et al. 2007a). We hypothesized that cardiac arousals can be used as estimates for EEG awakenings. METHODS: Polysomnographic EEG awakenings and automatically detected cardiac activations were systematically compared using laboratory data of 112 subjects (47 male, mean ± SD age 37.9 ± 13 years), 985 nights and 23,855 aircraft noise events (ANEs). RESULTS: The overall agreement was higher in control (81.9 %) compared to noise nights (76.4 %). However, if corrected for chance expected agreement according to Landis and Koch (1977), agreement was higher in noise (к=0.60) compared to control nights (к=0.33), representing “moderate to substantial” and “fair” agreement respectively. The probability of automatically detected cardiac arousals increased monotonously with increasing maximum sound pressure levels of ANEs, exceeding the probability of EEG awakenings by up to 18.1 %. If spontaneous reactions were taken into account, exposure-response curves were practically identical for EEG awakenings and cardiac arousals. CONCLUSIONS: Automatically detected cardiac arousals can be used as estimates for EEG awakenings. This inexpensive, objective, and non-invasive method facilitates large scale field studies on the effects of traffic noise on sleep. More investigations are needed to further validate the ECG algorithm in the field and to investigate interindividual differences in its ability to predict EEG awakenings.

Development of a sleep disturbance index (SDI) for the assessment of noise-induced sleep disturbances

Abstract: This analysis was aimed at the development of a sleep disturbance index (SDI) which allows a reliable estimate of physiological sleep disturbances due to environmental influences such as noise. Seven variables, repeatedly reported to change during noise exposure, were derived from polysomnograms of a reference sample of 38 men and 28 women (19–34 yrs) as recorded under quiet conditions in the laboratory after at least one habituation night. The variables were then submitted to a principal component analysis. The scores of the first principal component that explained 35 % of the variance were used to calculate the SDI. Reliability was ascertained by application of the SDI to a quiet night for each of 82 persons of the same age range from two other laboratory studies where the index value did not differ from that of the reference sample. Validity was verified by significantly lower index values for quiet nights than for noisy nights of 50 persons (25 men, 25 women, 19–28 yrs) and for the first night in the laboratory of 62 persons (37 men, 25 women, 19–34 yrs). Moreover, the index value increased with increasing age of the 261 participants in two laboratory studies and a field study whose age varied between 18 and 68 years. The SDI may facilitate the interpretation of sleep disturbances caused by environmental influences and its application would improve the comparability of studies performed in this area.

Markov state transition models for the prediction of changes in sleep structure induced by aircraft noise

Abstract: OBJECTIVES: To quantitatively assess the effects of the introduction of a nocturnal air traffic curfew at Frankfurt Airport on sleep structure. METHODS: A six state (Wake, S1, S2, S3, S4 and REM) Markov state transition sleep model was built. Transition probabilities between states were calculated with autoregressive multinomial logistic regression based on polysomnographic laboratory study data. Monte Carlo simulation trials were performed for modelling a noise-free night and three noise scenarios: (1) traffic at Frankfurt Airport on 16 August 2005, (2) as (1), but flights between 11 pm and 5 am cancelled and (3) as (2), with flights between 11 pm and 5 am from (1) rescheduled to periods before 11 pm and after 5 am. RESULTS: The results indicate that there will be a small benefit for airport residents compared to the current situation even if all traffic is rescheduled (average time spent awake -3.2 %, S1 -4.6 %, S2 -0.9 %, S3 +3 %, S4 +9.2 %, REM +0.6 %, number of sleep stage changes -2.5 %). This benefit is likely to be outweighed by the increase in air traffic during shoulder hours, especially for those who choose to or have to go to bed before 10:30 pm or after 1 am. CONCLUSIONS: Alternative strategies might be necessary to both guarantee undisturbed sleep of airport residents and to minimize economic and legal disadvantages accompanied by a traffic curfew. The models developed in this investigation may serve as a valuable tool for optimizing air traffic patterns at airports, and therefore guide political decision making.

Aircraft noise effects on sleep: Substantiation of the DLR protection concept for airport Leipzig/Halle

Abstract: The Institute of Aerospace Medicine at the German Aerospace Center (DLR) investigated the influence of nocturnal aircraft noise on sleep in polysomnographical laboratory and field studies between 1999 and 2004. The results of the field study were used by the Regional Council of Leipzig (Germany) for the establishment of a noise protection plan in the official approval process for the expansion of Leipzig/Halle airport to an international freight hub. Of the results, special attention is given to the exposure-response relationship between the maximum sound pressure level of an aircraft noise event and the probability to wake up, which was used to establish noise protection zones directly related to the effects of noise on sleep. These protection zones differ qualitatively and quantitatively from zones that are solely based on acoustical criteria. The noise protection plan for Leipzig/Halle airport is presented and substantiated: (1) on average, there should be less than one additional awakening induced by aircraft noise, (2) awakenings recalled in the morning should be avoided as much as possible, and (3) aircraft noise should interfere as little as possible with the process of falling asleep again. Issues concerned with the representativeness of the study sample are discussed.

Nächtlicher Flug-, Straßen- und Schienenverkehrslärm: Belästigungsunterschiede und kumulative Wirkungen

Abstract: G eräuscheinwirkungen können in vielfältiger Weise die Lebensbedingungen beeinträchtigen. Jedes hörbare Geräusch, das zu Belästigungen, Störungen oder gar gesundheit lichen Beeinträchtigungen führt, wird als Lärm bezeichnet. Zu den Hauptwirkungen von Lärm zählen Belästigungen. Sie werden primär durch die Störung der Kommunikation, der Erholung und Entspannung, einschließlich des Nachtschlafs, hervorgerufen und vermindern das individuelle Wohlbefinden. Da sich die Belästigung, zeitlich verzögert, den sog. primären Lärmwirkungen (z. B. Schlafstörungen) anschließt, gehört sie zu den Sekundärreaktionen. Hierzu zählen auch z. B. die empfundene Schlafqualität oder Änderungen der Befindlichkeit am Morgen nach einer lärmexponierten Nacht. Viele Lärmwirkungsstudien zeigen, dass die Geräuschbelastung der Bevölkerung in Deutschland primär durch Verkehrslärm und hier besonders stark durch den Straßenverkehrslärm hervorgerufen wird. Nach Erhebungen des Umweltbundesamts ist knapp die Hälfte der Bevölkerung durch Straßenverkehr mit Mittelungspegeln LM über 55 dB(A) am Tag belastet, bei denen Beeinträchtigungen des physischen und psychischen Wohlbefindens zu erwarten sind [1; 2]. Beim Schienenverkehr beträgt der Anteil ca. 20 %. Die berechnete Geräuschbelastung der Bevölkerung (alte Bundesländer) durch Straßenund Schienenverkehr ist laut Umweltbundesamt auch nachts an vielen Stellen hoch1). So ist etwa die Hälfte der Bevölkerung nachts durch Straßenverkehr Pegeln ausgesetzt (LM > 45dB(A)), bei denen mit Beeinträchtigungen des Schlafs bei geöffnetem Fenster gerechnet werden muss. Beim Schienenverkehr beträgt der Anteil ca. 37 %. Betrachtet man nur die Gruppe der „hochgradig“ Belästigten, sind 18 % der Bevölkerung stark bzw. äußerst stark gestört und belästigt. Der Flugverkehr, als zweitwichtigste Verkehrslärmquelle, belästigt knapp 6 % der Bevölkerung äußerst bzw. stark; beim Schienenverkehr sind es etwa 5 %. Trotz der mitunter geringen Vergleichbarkeit der Lästigkeitsangaben haben sich verschiedene Lärmwirkungsstudien der quellenspezifischen Wirkung von Fluglärm, Schienenlärm, Straßenlärm und anderen Lärmarten gewidmet [3 bis 8]. Die Beschreibung der akustischen Belastung erfolgt dabei meistens durch die Berechnung des energieäquivalenten Dauerschallpegels. Dass dieser nicht zwangsläufig mit einer entsprechenden Wirkungsäquivalenz verbunden ist, zeigen die Dosis-Wirkungs-Kurven aus diesen Untersuchungen. Die international am häufigsten diskutierten Kurven stammen von Miedema und Vos [7] und beschreiben Beziehungen für den Prozentsatz der durch die Geräuscharten Straße, Schiene und Fluglärm stark belästigten Personen. Erkennbar ist, dass die Steigung der Fluglärmkurve steiler verläuft als die von Straßenund Schienenverkehrslärm. Dies bedeutet, dass bei gleichem Pegelzuwachs (in LDN) prozentual mehr Personen durch Fluglärm Zusammenfassung Viele in der Vergangenheit durchgeführte Studien deuten darauf hin, dass die Belästigung bei gleichem Dauerschallpegel am Tag in der Reihenfolge Schienenverkehrslärm, Straßenverkehrslärm, Fluglärm ansteigt. In der hier vorgestellten Studie sollte untersucht werden, ob sich bei nächtlicher Lärmexposition die gleichen Unterschiede in der Belästigung zwischen den Verkehrsträgern finden. Zudem sollte untersucht werden, inwiefern sich Belästigungsurteile bei gleichzeitiger Beschallung mit Lärm von zwei oder drei Verkehrträgern ändern. Als Datenbasis dienten Befragungen aus drei Schlaflaborstudien des DLR-Instituts für Luftund Raumfahrtmedizin zur Belästigungswirkung und zu subjektiven Schlafstörungen von Flug-, Straßenverkehrsund Bahnlärm, die mit 72 Probanden durchgeführt wurden. Im direkten Vergleich wird die höchste Belästigung durch Fluglärm ausgelöst, gefolgt von der Belästigung durch Schienenlärm an zweiter und Straßenlärmbelästigung an dritter Position. Eine mögliche Erklärung für die gefundene Rangfolge besteht in der zeit lichen Länge der verwendeten Verkehrsgeräusche, von denen die Fluggeräusche im Vergleich zu den Straßenverkehrsund Bahngeräuschen am längsten waren. Die Fluglärmbelästigung wird anders als die Belästigung durch Schienenoder Straßenverkehrslärm durch die Lärmwirkung eines zweiten bzw. dritten Verkehrsträgers verstärkt. Die Doppelexposition aus Flugund Schienenlärm bzw. die Dreifachexposition mit allen drei Verkehrslärmarten ruft eine signifikant stärkere Belästigungsreaktion hervor als die reine Exposition mit Fluggeräuschen. Dieser kumulative Effekt ist ein Hinweis darauf, dass bei Beurteilung von Geräuschsituationen, in denen mehr als eine Verkehrslärmart vorhanden ist, die einzelnen Quellen nicht getrennt voneinander zu bewerten sind.

The sleep disturbance index - A measure for structural alterations of sleep due to environmental influences

Abstract: SUMMARY Sleep disturbances caused by noise and other environmental influences are usually rather moderate but have a rather typical pattern with reduced times in slow-wavesleep (SWS) and in REM-sleep, with delays of sleep onset and of the first occurrence of SWS, with prolonged wakefulness after sleep onset and sleep stage S1 as well as an increase of the number of wake periods longer than 3 minutes. This paper presents a newly developed sleep disturbance index (SDI) that constitutes a reliable and valid indicator of physiological sleep quality. It was developed on the basis of the 7 aforementioned sleep parameters derived from polysomnograms recorded during an undisturbed night of 38 men and 28 women (19-34 yrs, reference sample). Reliability was ascertained by application of the SDI to a quiet night of 82 persons of the same age from two other laboratory studies. Validity was verified by significantly higher index-values indicating more disturbed sleep, that were determined for noisy nights of 50 persons (25 men, 25 women, 19-28 yrs) and for the first night in the laboratory of 62 persons (37 men, 25 women, 19-34 yrs) as compared with quiet reference nights of the respective sample. Further the index-values increased with age as determined with polysomnograms from 193 participants observed in the laboratory and 56 persons observed in a field study whose age varied between 18 and 68.