Alexander Samel

Bio: Alexander Samel is an academic researcher from German Aerospace Center. The author has contributed to research in topics: Poison control & Circadian rhythm. The author has an hindex of 17, co-authored 36 publications receiving 1013 citations.

Schlafphysiologische Bewertung nächtlicher Flugbetriebsbeschränkungen vor dem Hintergrund aktueller Urteile des Bundesverwaltungsgerichts

Abstract: Nachtflugverbote haben fur Konzepte zum Schutz der Bevolkerung vor den Folgen nachtlichen Fluglarms an Bedeutung gewonnen, seitdem das Bundesverwaltungsgericht im Jahre 2006 der planfeststellenden Behorde im Fall Flughafen Berlin Brandenburg lnternational (BBI) die beantragte, bis auf wenige Ausnahmen uneingeschrankte Betriebserlaubnis in der Nacht versagt hat und im Fall Flughafen Leipzig/Halle (FLH) zwar den nachtlichen Verkehr des Express-Fracht-Kreuzes billigte, im Ubrigen aber wie bei BBI eine erneute Abwagung der Zulassung nachtlichen Flugverkehrs verlangte. Das hohere passive Schallschutzniveau des DLR-Konzepts im Vergleich zu anderen Schutzkonzepten spielte im Fall Leipzig/Halle fur das Bundesverwaltungsgericht keine entscheidende Rolle. Anhand subjektiver Daten zu Bettzeiten und objektiver Daten zum Schlafverhalten werden mogliche Folgen der durch das Bundesverwaltungsgericht vorgenommenen Dreiteilung der Nacht in Kernruhezeit (0:00 bis 5:00 Uhr), Nachtrandstunden (22:00 bis 0:00 Uhr und 5:00 bis 6:00 Uhr) und Tagesstunden fur den Schutz des Schlafs diskutiert. Die Autoren kommen zu dem Schluss, dass aus schlafphysiologischer Sicht (1) die Tagesrandstunden keineswegs als unproblematisch eingestuft werden durfen, insbesondere fur die nicht erwachsene Bevolkerung und bei Flughafen mit relevantem Verkehrsaufkommen in dieser Zeitperiode, (2) dass es deshalb bei derzeitigem Kenntnisstand unklar ist bzw. einer Einzelfallprufung unterliegt, ob eine Kernruhezeit einem kontingentierten, aber zeitlich unbeschrankten Flugbetrieb in der Nacht tatsachlich vorzuziehen ist, und dass (3) die Gleichstellung der fur BBI und FLH aufgestellten Schutzkonzepte hinsichtlich ihrer grundsatzlichen Eignung zur Abwehr unzumutbarer Belastungen durch das Bundesverwaltungsgericht wahrscheinlich dazu fuhren wird, dass bevorzugt das Schutzkonzept mit dem geringeren Schutzniveau Anwendung findet, was aus schlafphysiologischer Sicht nicht unbedenklich ist.

Investigation of the operability of noise-reduced approaches by pilots

Abstract: Aircraft noise threatens air traffic growth, since residents are annoyed or suffer from impairments due to increasing aircraft movements. Low-noise approaches become of particular interest as short- or medium-term countermeasures. However, aircrew performance during such approaches may change, as may their acceptance, and flight safety may be mitigated compared to standard approaches. Therefore, a segmented continuous descent approach (SCDA) was compared to a standard low drag low power approach (LDLP). 40 pilots were tested on an either A320 or A330 full-flight simulator during one LDLP and 3 SCDAs. Due to switching tasks between flying and non-flying pilots, each pilot conducted 8 approaches. Technical, physiological and psychological data were monitored using EEG, EOG, ECG, saliva cortisol, and questionnaires (fatigue, taskload, acceptance). Under the conditions investigated, only small deviations from the planned flight paths were observed, indicating good performance. SCDA was rated rather non-problematic, and workload was acceptable. Taskload, fatigue, cortisol and ECG did not differ between the procedures. However, pilots rated SCDA as being less safe than LDLP. The simulator tests have been a first attempt to investigate noise reduced approaches under high fidelity conditions. Before discussing to introduce them into practice, further studies are strongly recommended, e.g. under real flight conditions.

Effects of nocturnal aircraft noise- Overview of the DLR human specific investigations

Abstract: 497] OBJECTIVES Studies on the effects of aircraft noise on sleep with a large subject sample as well as with high methodological expense are lacking, and hence statistically reliable recommendations for the protection against aircraft noise can presently not be made. However, scientifically based investigations are necessary for providing proper guidelines for authorities and users. METHODS DLR studied human reactions to nocturnal aircraft noise in laboratory and field experiments: In total, 192 healthy volunteers (m/f), aged 18 to 65 years, underwent 2240 study nights. In the isolation facility of the institute, 128 subjects were examined during 13 consecutive nights. 16 subjects served as control. For 112 subjects, aircraft noise events have been applied between 4 and 128 times per night (45 ≤ LAS,max ≤ 80 dB(A)). Sleep disturbances were assessed by EEG, EOG, EMG and EKG, by respiration, finger-pulse amplitude and position in bed. These signals were simultaneously recorded with the acoustic signals for calculating event-correlated reactions. The concentrations of cortisol, adrenalin and noradrenalin were determined from all night urine samples. At evening and morning, performance tests and questionnaires (fatigue, mood, annoyance) were applied. These data and results were examined in two field studies with 64 volunteers during 9 consecutive nights at their homes near Cologne airport. CONCLUSIONS The investigations will be concluded in March 2004. They are very ambitious and unique, even on a world wide standard. DLR wants to contribute by profound experimental knowledge to the very controversial disputes about the degree of impairing effects on human specific reactions to nocturnal aircraft noise.

The role of actigraphy in the study of sleep and circadian rhythms.

Abstract: In summary, although actigraphy is not as accurate as PSG for determining some sleep measurements, studies are in general agreement that actigraphy, with its ability to record continuously for long time periods, is more reliable than sleep logs which rely on the patients' recall of how many times they woke up or how long they slept during the night and is more reliable than observations which only capture short time periods Actigraphy can provide information obtainable in no other practical way It can also have a role in the medical care of patients with sleep disorders However, it should not be held to the same expectations as polysomnography Actigraphy is one-dimensional, whereas polysomnography comprises at least 3 distinct types of data (EEG, EOG, EMG), which jointly determine whether a person is asleep or awake It is therefore doubtful whether actigraphic data will ever be informationally equivalent to the PSG, although progress on hardware and data processing software is continuously being made Although the 1995 practice parameters paper determined that actigraphy was not appropriate for the diagnosis of sleep disorders, more recent studies suggest that for some disorders, actigraphy may be more practical than PSG While actigraphy is still not appropriate for the diagnosis of sleep disordered breathing or of periodic limb movements in sleep, it is highly appropriate for examining the sleep variability (ie, night-to-night variability) in patients with insomnia Actigraphy is also appropriate for the assessment of and stability of treatment effects of anything from hypnotic drugs to light treatment to CPAP, particularly if assessments are done before and after the start of treatment A recent independent review of the actigraphy literature by Sadeh and Acebo reached many of these same conclusions Some of the research studies failed to find relationships between sleep measures and health-related symptoms The interpretation of these data is also not clear-cut Is it that the actigraph is not reliable enough to the access the relationship between sleep changes and quality of life measures, or, is it that, in fact, there is no relationship between sleep in that population and quality of life measures? Other studies of sleep disordered breathing, where actigraphy was not used and was not an outcome measure also failed to find any relationship with quality of life Is it then the actigraph that is not reliable or that the associations just do not exist? The one area where actigraphy can be used for clinical diagnosis is in the evaluation of circadian rhythm disorders Actigraphy has been shown to be very good for identifying rhythms Results of actigraphic recordings correlate well with measurements of melatonin and of core body temperature rhythms Activity records also show sleep disturbance when sleep is attempted at an unfavorable phase of the circadian cycle Actigraphy therefore would be particularly good for aiding in the diagnosis of delayed or advanced sleep phase syndrome, non-24-hour-sleep syndrome and in the evaluation of sleep disturbances in shift workers It must be remembered, however, that overt rest-activity rhythms are susceptible to various masking effects, so they may not always show the underlying rhythm of the endogenous circadian pacemaker In conclusion, the latest set of research articles suggest that in the clinical setting, actigraphy is reliable for evaluating sleep patterns in patients with insomnia, for studying the effect of treatments designed to improve sleep, in the diagnosis of circadian rhythm disorders (including shift work), and in evaluating sleep in individuals who are less likely to tolerate PSG, such as infants and demented elderly While actigraphy has been used in research studies for many years, up to now, methodological issues had not been systematically addressed in clinical research and practice Those issues have now been addressed and actigraphy may now be reaching the maturity needed for application in the clinical arena

The Role of Actigraphy in the Study of Sleep and Circadian Rhythms AMERICAN ACADEMY OF SLEEP MEDICINE REVIEW PAPER

Abstract: 1.0 BACKGROUND ACTIGRAPHY HAS BEEN USED TO STUDY SLEEP/WAKE PATTERNS FOR OVER 20 YEARS. The advantage of actigraphy over traditional polysomnography (PSG) is that actigraphy can conveniently record continuously for 24-hours a day for days, weeks or even longer. In 1995, Sadeh et al.,1 under the auspices of the American Sleep Disorders Association (now called the American Academy of Sleep Medicine, AASM), reviewed the current knowledge about the role of actigraphy in the evaluation of sleep disorders. They concluded that actigraphy does provide useful information and that it may be a “cost-effective method for assessing specific sleep disorders...[but that] methodological issues have not been systematically addressed in clinical research and practice.” Based on that task force’s report, the AASM Standards of Practice Committee concluded that actigraphy was not indicated for routine diagnosis or for assessment of severity or management of sleep disorders, but might be a useful adjunct for diagnosing insomnia, circadian rhythm disorders or excessive sleepiness.2 Since that time, actigraph technology has improved, and many more studies have been conducted. Several review papers have concluded that wrist actigraphy can usefully approximate sleep versus wake state during 24 hours and have noted that actigraphy has been used for monitoring insomnia, circadian sleep/wake disturbances, and periodic limb movement disorder.3,4 This paper begins where the 1995 paper left off. Under the auspices of the AASM, a new task force was established to review the current state of the art of this technology.

Auditory and non-auditory eff ects of noise on health

Abstract: Noise is pervasive in everyday life and can cause both auditory and non-auditory health eff ects. Noise-induced hearing loss remains highly prevalent in occupational settings, and is increasingly caused by social noise exposure (eg, through personal music players). Our understanding of molecular mechanisms involved in noise-induced haircell and nerve damage has substantially increased, and preventive and therapeutic drugs will probably become available within 10 years. Evidence of the non-auditory eff ects of environmental noise exposure on public health is growing. Observational and experimental studies have shown that noise exposure leads to annoyance, disturbs sleep and causes daytime sleepiness, aff ects patient outcomes and staff performance in hospitals, increases the occurrence of hypertension and cardiovascular disease, and impairs cognitive performance in schoolchildren. In this Review, we stress the importance of adequate noise prevention and mitigation strategies for public health.

Sleep and circadian rhythm disruption in psychiatric and neurodegenerative disease

Abstract: Sleep and circadian rhythm disruption are frequently observed in patients with psychiatric disorders and neurodegenerative disease. The abnormal sleep that is experienced by these patients is largely assumed to be the product of medication or some other influence that is not well defined. However, normal brain function and the generation of sleep are linked by common neurotransmitter systems and regulatory pathways. Disruption of sleep alters sleep-wake timing, destabilizes physiology and promotes a range of pathologies (from cognitive to metabolic defects) that are rarely considered to be associated with abnormal sleep. We propose that brain disorders and abnormal sleep have a common mechanistic origin and that many co-morbid pathologies that are found in brain disease arise from a destabilization of sleep mechanisms. The stabilization of sleep may be a means by which to reduce the symptoms of--and permit early intervention of--psychiatric and neurodegenerative disease.