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Showing papers in "Noise & Health in 2004"


Journal Article
TL;DR: Noise stress hypothesis chronic stress hormone dysregulations as well as increases of established endogenous risk factors of ischaemic heart diseases have been observed under long-term environmental noise exposure and an increased risk of myocardial infarction is to be expected.
Abstract: Traffic noise is the most important source of environmental annoyance. According to the Environmental Expert Council of Germany, severe annoyance persistent over prolonged periods of time is to be regarded as causing distress. Previously, extraaural noise effects were mostly assessed using a paradigm in which the sound level played the major role. On the basis of this paradigm the relatively low sound level of environmental noise was not considered to be a potential danger to health. In contrast to this numerous empirical results have shown long-term noise-induced health risks. Therefore a radical change of attitude - a change of paradigm - is necessary. For an immediate triggering of protective reactions (fight/flight or defeat reactions) the information conveyed by noise is very often more relevant than the sound level. It was shown recently that the first and fastest signal detection is mediated by a subcortical area - the amygdala. For this reason even during sleep the noise from aeroplanes or heavy goods vehicles may be categorised as danger signals and induce the release of stress hormones. In accordance with the noise stress hypothesis chronic stress hormone dysregulations as well as increases of established endogenous risk factors of ischaemic heart diseases have been observed under long-term environmental noise exposure. Therefore, an increased risk of myocardial infarction is to be expected. The results of individual studies on this subject in most cases do not reach statistical significance. However, according to the Environmental Expert Council, these studies show a consistent trend towards an increased cardiovascular risk if the daytime immission level exceeds 65 dB(A). Most of the previous studies on the extraaural effects of occupational noise have been invalidated by exposure misclassifications. In future studies on health effects of noise a correct exposure assessment is one of the most important preconditions.

436 citations


Journal Article
TL;DR: Conventional methods of assessing annoyance, typically based on A-weighted equivalent level, are inadequate for low frequency noise and lead to incorrect decisions by regulatory authorities, but do not deal adequately with fluctuations.
Abstract: Low frequency noise, the frequency range from about 10 Hz to 200 Hz, has been recognised as a special environmental noise problem, particularly to sensitive people in their homes. Conventional methods of assessing annoyance, typically based on A-weighted equivalent level, are inadequate for low frequency noise and lead to incorrect decisions by regulatory authorities. There have been a large number of laboratory measurements of annoyance by low frequency noise, each with different spectra and levels, making comparisons difficult, but the main conclusions are that annoyance of low frequencies increases rapidly with level. Additionally the A-weighted level underestimates the effects of low frequency noises. There is a possibility of learned aversion to low frequency noise, leading to annoyance and stress which may receive unsympathetic treatment from regulatory authorities. In particular, problems of the Hum often remain unresolved. An approximate estimate is that about 2.5% of the population may have a low frequency threshold which is at least 12 dB more sensitive than the average threshold, corresponding to nearly 1,000,000 persons in the 50-59 year old age group in the EU-15 countries. This is the group which generates many complaints. Low frequency noise specific criteria have been introduced in some countries, but do not deal adequately with fluctuations. Validation of the criteria has been for a limited range of noises and subjects.

186 citations


Journal Article
TL;DR: Traffic noise exposure, even at low levels, was associated with annoyance and sleep disturbance and access to a quiet side seemed to be a major protective factor for noise related problems.
Abstract: Traffic noise, which is steadily increasing, is considered to be an important environmental health problem. The aim of this study was to estimate the degree of annoyance and sleep disturbance related to road traffic noise in residential settings in an urban community. The study is based on a questionnaire on environmentally related health effects distributed to a stratified random sample of 1000 individuals, 19-80 years old, in a municipality with heavy traffic in the county of Stockholm. The response rate was 76%. The individual noise exposure was estimated using evaluated noise dispersion models and local noise assessments. Frequent annoyance was reported by 13% of subjects exposed to Leq 24 hr >50 dBA compared to 2% among those exposed to 50 dBA and by 13% at levels 55 dBA Leq 24 hr). There was some habituation to noise for problems related to sleep but not for annoyance. The prevalence of both annoyance and sleep problems was higher when bedroom windows were facing streets. People living in apartments had more sleep problems compared to people living in detached or semi-detached houses. In conclusion traffic noise exposure, even at low levels, was associated with annoyance and sleep disturbance. Access to a quiet side seemed to be a major protective factor for noise related problems.

159 citations


Journal Article
TL;DR: The human perception of sound at frequencies below 200 Hz is reviewed and some investigations give evidence of persons with an extraordinary sensitivity in the low and infrasonic frequency range, but further research is needed in order to confirm and explain this phenomenon.
Abstract: The human perception of sound at frequencies below 200 Hz is reviewed. Knowledge about our perception of this frequency range is important, since much of the sound we are exposed to in our everyday environment contains significant energy in this range. Sound at 20-200 Hz is called low-frequency sound, while for sound below 20 Hz the term infrasound is used. The hearing becomes gradually less sensitive for decreasing frequency, but despite the general understanding that infrasound is inaudible, humans can perceive infrasound, if the level is sufficiently high. The ear is the primary organ for sensing infrasound, but at levels somewhat above the hearing threshold it is possible to feel vibrations in various parts of the body. The threshold of hearing is standardized for frequencies down to 20 Hz, but there is a reasonably good agreement between investigations below this frequency. It is not only the sensitivity but also the perceived character of a sound that changes with decreasing frequency. Pure tones become gradually less continuous, the tonal sensation ceases around 20 Hz, and below 10 Hz it is possible to perceive the single cycles of the sound. A sensation of pressure at the eardrums also occurs. The dynamic range of the auditory system decreases with decreasing frequency. This compression can be seen in the equal-loudness-level contours, and it implies that a slight increase in level can change the perceived loudness from barely audible to loud. Combined with the natural spread in thresholds, it may have the effect that a sound, which is inaudible to some people, may be loud to others. Some investigations give evidence of persons with an extraordinary sensitivity in the low and infrasonic frequency range, but further research is needed in order to confirm and explain this phenomenon.

143 citations


Journal Article
TL;DR: Use of hearing protection and self-reported hearing-related symptoms, such as tinnitus and noise sensitivity, in a young population of high-school students (N=1285), aged 13 to 19 years is studied.
Abstract: It seems to be a common opinion among researchers within the field of audiology that the prevalence of tinnitus will increase as a consequence of environmental factors, for example exposure to loud noise. Young people are exposed to loud sounds, more than any other age group, especially during leisure time activities, i.e. at pop concerts, discotheques and gyms. A crucial factor for the prevention of hearing impairments and hearing-related symptoms in the young population is the use of hearing protection. The focus of the present study is use of hearing protection and self-reported hearing-related symptoms, such as tinnitus and noise sensitivity in a young population of high-school students (N=1285), aged 13 to 19 years. The results show that the prevalence of permanent tinnitus and noise sensitivity, reported in the total group, was 8.7% and 17.1% respectively. Permanent tinnitus was not significantly related to level of socio-economic status, but age-related differences in the prevalence rates of experienced tinnitus and noise sensitivity were found to be significant. Older students reported such symptoms to a greater extent than younger students did. Those who reported tinnitus and other hearing-related symptoms protected their hearing to the highest extent and were the ones most worried.

120 citations


Journal Article
TL;DR: It was found that adolescents' attitudes and behaviours regarding hearing protection use differed between levels of socio-economic status, and individuals with high SES expressed more negative attitudes and used ear protection to a greater extent than those with lower SES.
Abstract: The focus of the present study, of 1285 adolescents, was young people's attitudes towards noise and their use of hearing protection at discos and pop concerts. Comparisons were made between adolescents from different age groups, and with different socio-economic status. Logistic regressions indicated that "worry before attending noisy activities" and "hearing symptoms" such as tinnitus and noise sensitivity could, to some degree, explain the use of hearing protection in noisy environments. Another conclusion to be drawn from this study was that adolescents' attitudes and behaviors regarding hearing protection use differed between levels of socio-economic status. Individuals with high SES expressed more negative attitudes and used ear protection to a greater extent than those with lower SES. This result might indicate differences in the development of future auditory problems among individuals with different levels of socio-economic status. The cause of hearing impairment and tinnitus may not be restricted merely to noise exposure. Psychological aspects, such as attitudes towards noisy environments and the individual's behavior regarding the use of hearing protection may be considered as important factors in the understanding of why the prevalence of hearing­ related problems has increased among adolescents.

84 citations


Journal Article
TL;DR: It can be concluded that high exposure to traffic noise, especially at nighttime, activates the HPA axis and this leads in the long term to an aggravation of bronchitis in children.
Abstract: A correlation of respiratory diseases to traffic related air pollution and noise was observed in an interview study. Since in that study the exposure was subjectively assessed, in the present field study nitrogen dioxide as indicator for vehicle exhausts and the mean night-time noise level were measured outside the children's windows in representative locations. Based on these measurements each child was placed in one of the following categories: low, medium or high traffic immission (ambient emissions). The physician contacts due to bronchitis of 68 children were assessed retrospectively from the files of the participating paediatricians. Saliva samples were collected from all children and the cortisol concentration was estimated. Children under high noise exposure (L(night, 8h) = 54-70dB(A)) had in comparison to all other children significantly increased morning saliva cortisol concentrations, indicating an activation of the hypothalamus-pituitary-adrenal (HPA) axis. Analysing a subgroup of children without high noise exposure showed, that children with frequent physician contacts due to bronchitis did not have increased morning saliva cortisol. However, multiple regression analysis with stepwise exclusion of variables showed that bronchitis was correlated more closely to morning salvia cortisol than to traffic immissions. On the other hand, the rate of physician contacts due to bronchitis increased in a dose dependent manner and significantly with increasing traffic immissions. From these results it can be concluded that high exposure to traffic noise, especially at nighttime, activates the HPA axis and this leads in the long term to an aggravation of bronchitis in children. This seems to be more important than the effect of exhaust fumes on bronchitis symptoms. The results of the present study should be subjected to further investigation using specially designed studies.

74 citations


Journal Article
TL;DR: A procedure for estimating future annoyance in changed noise situations is proposed, including the analysis of possible statistical trends of the annoyance reactions over the years - even for steady-state noise loads, and with changing state situations, the effects of the change should be accounted for.
Abstract: When planning the development or reduction of large traffic facilities, acoustic calculation procedures are used to forecast the noise load in the affected residential areas. Then, existing dose/response relationships for steady state situations are used to predict noise effects in future years. Planners often assume that (1) noise annoyance reactions of residents do not change over the years, and (2) annoyance is not affected by the change itself. Both of these assumptions are questioned in this paper, and a procedure for estimating future annoyance in changed noise situations is proposed. This includes the analysis of possible statistical trends of the annoyance reactions over the years - even for steady-state noise loads, and with changing state situations, the effects of the change should also be accounted for.

66 citations


Journal Article
TL;DR: It is argued that there need studies of RT effects in realistic long-lasting listening situations to better understand the effect of RT on speech communication and the effect on distraction and mood need to be better understood.
Abstract: The paper presents a theoretical analysis of possible effects of reverberation time on the cognitive load in speech communication. Speech comprehension requires not only phonological processing of the spoken words. Simultaneously, this information must be further processed and stored. All this processing takes place in the working memory, which has a limited processing capacity. The more resources that are allocated to word identification, the fewer resources are therefore left for the further processing and storing of the information. Reverberation conditions that allow the identification of almost all words may therefore still interfere with speech comprehension and memory storing. These problems are likely to be especially serious in situations where speech has to be followed continuously for a long time. An unfavorable reverberation time (RT) then could contribute to the development of cognitive fatigue, which means that working memory resources are gradually reduced. RT may also affect the cognitive load in two other ways: RT may change the distracting effects of a sound and a person's mood. Both effects could influence the cognitive load of a listener. It is argued that we need studies of RT effects in realistic long-lasting listening situations to better understand the effect of RT on speech communication. Furthermore, the effect of RT on distraction and mood need to be better understood.

59 citations


Journal Article
TL;DR: This review concentrates on the effects of low frequency noise (LFN) up to 100 Hz on selected physiological parameters, subjective complaints and performance, and modelling to analyse the transmission of the acoustic energy from the input into the body to the structures containing sensors.
Abstract: This review concentrates on the effects of low frequency noise (LFN) up to 100 Hz on selected physiological parameters, subjective complaints and performance. The results of laboratory experiments and field studies are discussed in relation to the thresholds of hearing, of vibrotactile sensation and of aural pain. The effects of LFN may be mediated trough different ways. Temporary or permanent hearing threshold shifts seem to be due to acoustic stimuli above the individual hearing threshold. However, non-aural physiological and psychological effects may be caused by levels of low frequency noise below the individual hearing threshold. The dynamic range between the thresholds of hearing and of aural pain diminishes with decreasing frequency. This should be taken into account by the setting of limits concerning the health risks. Sufficient safety margins are recommended. The use of a frequency weighting with an attenuation of the low frequencies (e.g. G-weighting) does not seem to be appropriate for the evaluation of the health risks caused by LFN up to 100 Hz. It may be proposed to measure third octave band spectra or narrow band spectra. A comparison with the known human responses caused by the measured levels and frequencies could help to evaluate the health risks. Some proposals for further investigations were given: (1) experimental methods to discover the ways mediating the effects of low frequency noise, (2) consideration of the individual hearing threshold or hearing threshold shift and of the vibrotactile threshold in the low frequency range to be able to judge the effects, (3) consideration of combined body vibration caused by airborne low frequency noise or by other sources, (4) modelling to analyse the transmission of the acoustic energy from the input into the body to the structures containing sensors, (5) consideration of probable risk groups like children or pregnant women.

54 citations


Journal Article
TL;DR: A significant dose-response relationship was found between aircraft noise exposure at home and performance on memory tests of immediate/delayed recall, however there was no strong association with the other cognitive outcomes.
Abstract: The association of aircraft noise exposure with cognitive performance was examined by means of a cross-sectional field survey. Two hundred thirty six children attending 10 primary schools around Heathrow Airport in west London were tested on reading comprehension, immediate/delayed recall and sustained attention. In order to obtain the information about their background, a questionnaire was delivered to the parents and 163 answers were collected. Logistic regression models were used to assess performance on the cognitive tests in relation to aircraft noise exposure at home and possible individual and school level confounding factors. A significant dose-response relationship was found between aircraft noise exposure at home and performance on memory tests of immediate/delayed recall. However there was no strong association with the other cognitive outcomes. These results suggest that aircraft noise exposure at home may affect children's memory.

Journal Article
TL;DR: Noise-induced sleep disturbances comprise alterations during bedtimes such as awakenings, sleep stage changes, body movements and after-effects such as subjectively felt decrease of sleep quality, impairment of mood and performance.
Abstract: Due to the undisputable restorative function of sleep, noise-induced sleep disturbances are regarded as the most deleterious effects of noise. They comprise alterations during bedtimes such as awakenings, sleep stage changes, body movements and after-effects such as subjectively felt decrease of sleep quality, impairment of mood and performance. The extents of these reactions depend on the information content of noise, on its acoustical parameters and are modified by individual influences and by situational conditions. Intermittent noise, that is produced by air traffic, rail traffic and by road traffic during the night is particularly disturbing and needs to be reduced. Suitable limits are suggested.

Journal Article
TL;DR: Based upon a physiological model calculating the cortisol accumulation starting at a nightly threshold of physiological over-proportional reactions around Lmax = 53 dB(A) the number of tolerable noise events can be estimated for given indoor peak sound pressure levels, keeping the cortisol increase within the normal range.
Abstract: Mainly dependent on level and dynamic increase sound produces over-shooting excitations which activate subcortical processing centers (e.g. the amygdala, functioning as fear conditioning center) besides cortical areas (e. g. arousing annoyance, awakenings) as well. In addition there exist very close central nervous connections between subcortical parts of the auditory system (e.g. amygdala) showing typical plasticity effects (sensitization) and the hypothalmic-pituitary-adrenal (HPA)-axis. Using that causal chain noise induce cortisol excretion even below the awakening threshold. Thus repeated noise events (e.g. overflights during night time) may lead to accumulation of the cortisol level in blood. This can happen because its time-constant of exponential decrease is about 50 to 10 times larger than that one for adrenaline and noradrenaline. This fact and the unusual large permeability of cortisol through the cell membranes opens a wide field of connections between stress-dependent cortisol production and the disturbance of a large number of other endocrine processes, especially as a result of long-term stress activation by environmental influences such as environmental noise. Based upon a physiological model calculating the cortisol accumulation starting at a nightly threshold of physiological over-proportional reactions around Lmax = 53 dB(A) the number of tolerable noise events (over-flights in a nightly time range) can be estimated for given indoor peak sound pressure levels, keeping the cortisol increase within the normal range. Examples of results for 8 hours in the night are for instance number and level combinations (NAL-values) of 13 events with 53 dB(A) indoor peak level or 6 events with 70 dB(A) indoor peak level respectively.

Journal Article
TL;DR: Based on findings from available epidemiological and experimental studies, the review gives indications that sleep disturbance due to low frequency noise warrants further concern.
Abstract: Low frequency noise (20-200 Hz) is emitted by numerous sources in the society. As low frequencies propagate with little attenuation through walls and windows, many people may be exposed to low frequency noise in their dwellings. Sleep disturbance, especially with regard to time to fall asleep and tiredness in the morning, are commonly reported in case studies on low frequency noise. However, the number of studies where sleep disturbance is investigated in relation to the low frequencies in the noise is limited. Based on findings from available epidemiological and experimental studies, the review gives indications that sleep disturbance due to low frequency noise warrants further concern.

Journal Article
TL;DR: The evidence of the association between community noise and cardiovascular outcomes is evaluated and the results of epidemiological studies in this field can be used for decision making when assessing maximum acceptable noise levels in the community.
Abstract: The WHO definition of "health" is critically discussed in its broad context. Decision making in noise policy has to be made in the evaluation range between social and physical well-being. The term "adverse" is a crucial one in the process of risk characterization. In toxicological terms it refers to the single event itself; in psychosocial terms it refers to the relative number of people affected. The evidence of the association between community noise and cardiovascular outcomes is evaluated. The results of epidemiological studies in this field can be used for decision making when assessing maximum acceptable noise levels in the community. Since dose response relationships were mostly studied with respect to road traffic noise, inferences have to be made with respect to aircraft noise. Issues of statistical inferring are discussed.

Journal Article
TL;DR: Findings derived from arousal and stress hormone research make possible a new access to the noise induced nightly health risk in sleep and, in the long-run, health.
Abstract: In noise effect research often the awakening reaction is maintained to be the only important health related reaction. The main argument is that sleep represents a trophotropic phase ("energy storing"). In contrast to this awakening reactions or lying awake belong to the ergotropic phase ("energy consuming"). Frequent or long awakening reactions endanger therefore the necessary recovery in sleep and, in the long-run, health. Findings derived from arousal and stress hormone research make possible a new access to the noise induced nightly health risk. An arousal is a short change in sleeping condition, raising the organism from a lower level of excitation to a higher one. Arousals have the function to prevent life-threatening influences or events through activation of compensation mechanisms. Frequent occurrences of arousal triggered by nocturnal noise leads to a deformation of the circadian rhythm. Additionally, the deep sleep phases in the first part of the night are normally associated with a minimum of cortisol and a maximum of growth hormone concentrations. These circadian rhythms of sleep and neuroendocrine regulation are necessary for the physical as well as for the psychic recovery of the sleeper. Noise exposure during sleep which causes frequent arousal leads to decreased performance capacity, drowsiness and tiredness during the day. Long-term disturbances of the described circadian rhythms have a deteriorating effect on health, even when noise induced awakenings are avoided.

Journal Article
TL;DR: Elevated metabolic rate caused by micro-arousal and/or insomnia, may play an additional role in health impairment, and the effects on health, and disturbed performance capacity during the day are shown by self ratings of 160 patients.
Abstract: World wide rules for sleep staging originate to 1967. Since then many investigations aimed to give numbers for the degree of sleep disturbances due to air traffic noise. But the variables used, such as the amount of relative sleep stages, total sleep time, or sleep efficiency, could not explain impairment in health and performance sufficiently. The beginning of the eighties has given new insight into the restorative functions of sleep, according to sleep fragmentation by micro-arousals. These are originating in autonomous dysfunctions during sleep, leading to non-restorative sleep. Environmentally related sleep disturbances are described, EEG and vegetative (micro)-arousals, and the actual knowledge in sleep medicine is given in terms of the international classification of sleep disorders (ICSD). The effects on health, and disturbed performance capacity during the day are shown by self ratings of 160 patients. Elevated metabolic rate caused by micro-arousal and/or insomnia, may play an additional role in health impairment.

Journal Article
TL;DR: Short-term noise exposure experiments do not provide information about the effects of long-term real life exposure to environmental noise, and potential health effects of chronic noise-induced disturbances of activities are discussed.
Abstract: Reactions to noise-induced communication disturbance of 42 men during a seminar were investigated. Stress reactions with or without road traffic noise (Lm = 60 dBA) were compared. Traffic noise was played back via loudspeakers during one day in the seminar room. The following parameters were measured: Fatigue and mental tension by questionnaire; blood pressure and heart rate; excretion of adrenaline, noradrenaline and cAMP from the collected urine. The same subjects participated in a laboratory test where the blood pressure was measured during 5 minutes of rest and after 5 minutes of exposure to intermittent white noise (Lm=97 dBA). It was found that the noise in the field experiment caused psychological and physiological stress effects in half of the subjects. Increased mental tension was correlated to increases as well as decreases of the blood pressure. Systolic blood pressure reactions were stronger than the reactions of diastolic blood pressure. Noise sensitive subjects reacted stronger than the others. In the short-term laboratory test, systolic blood pressure increases were smaller than the diastolic increases. At the end of the 5 minutes noise exposure only the diastolic blood pressure increases were significant. There was no correlation between the blood pressure reactions in the two different noise exposure experiments. There existed a positive correlation between noise sensitivity and the systolic blood pressure increases during the seminar, whilst the correlation, between noise sensitivity and systolic blood pressure increases in the laboratory exposure, was negative. From these results we conclude that short-term noise exposure experiments do not provide information about the effects of long-term real life exposure to environmental noise. Potential health effects of chronic noise-induced disturbances of activities are discussed.

Journal Article
TL;DR: Based on a real case effects of long-term exposure of infrasound on man, a small heating plant was identified, which immitted into the house of the exposed people very low frequency airborne sound far below the common hearing thresholds.
Abstract: Based on a real case effects of long-term exposure of infrasound on man are outlined. Beside a description of the background of the case together with remarks on the occurred health problems, the main view lies on the proceeding in identifying the special kind of exposure just as possible technical causes. As a source of annoyance a small heating plant was identified, which immitted into the house of the exposed people very low frequency airborne sound far below the common hearing thresholds. The results show clearly the general deficit of research on the effects of low level infrasound on man.

Journal Article
TL;DR: Evaluation criteria for aircraft noise for the prediction of noise effects and for the protection of residents living in the vicinity of (newly constructed or extended) civil airports are suggested.
Abstract: Based on extensive and detailed reviews the present paper suggests evaluation criteria for aircraft noise for the prediction of noise effects and for the protection of residents living in the vicinity of (newly constructed or extended) civil airports. The protection concept provides graded evaluation criteria: Critical loads indicate noise loads that shall be tolerated only exceptionally during a limited time. Protection Guides are central evaluation criteria for taking actions to reduce noise immission. Threshold values inform about measurable physiological and psychological reactions due to noise exposures where long term adverse health effects are not expected. Evaluation criteria are provided for various protection goals, for hearing, communication and sleep, for the avoidance of annoyance and of suspected cardiovascular diseases. As protection of the residents is understood as a dynamic process, these criteria must be repeatedly tested and adapted to new scientific findings.

Journal Article
TL;DR: A large-scale, multi-stage study for investigating the acute effects of nocturnal aircraft noise on human sleep is conducted in the framework of the HGF/DLR project "Quiet Air Traffic" for developing sustainable assessment criteria for human-specific effects of aircraft noise at night.
Abstract: Noise protection associated with the construction and extension of airports in the Federal Republic of Germany has been regulated by the law for protection against aircraft noise since 1971. This legislation is due for revision because of different aspects. One aspect is the growth of air traffic which has led many airports to the limits of their capacity and in search of new ways of adaptation to the increasing demand for flight services. Another aspect is the increasing concern of the population about noise effects which has to be addressed by better protection against the effects of aircraft noise. The framework conditions of policy in terms of society as a whole, its health and economic environment need to be put into effect by political action. Science can contribute to this goal by performing noise effects research and by providing recommendations to the political body. However, it remains controversial, what measures are necessary or adequate to assure effective protection of the population against aircraft noise. This is particularly true for the protection of rest and sleep at night. The problem of finding a common basis for adequate recommendations is associated with (1) the low number of primary studies, which also exhibited highly variable results and assessments, (2) the handling of acoustic or psycho-acoustic dimensions for quantifying psychological or physiological reactions, and (3) the conception of how far preventive measures have to go to prove effective. With this in mind, the DLR Institute for Aerospace Medicine is conducting a large-scale, multi-stage study for investigating the acute effects of nocturnal aircraft noise on human sleep. This enterprise is implemented in the framework of the HGF/DLR project "Quiet Air Traffic" for developing sustainable assessment criteria for human-specific effects of aircraft noise at night.

Journal Article
TL;DR: In this paper, the authors provided reference data of high frequency (HF) PTA over 3, 4 and 6 kHz for a general adult population, aged from 20 to 79 years, not exposed to hazardous occupational noise.
Abstract: Relevant reference data are required in order to determine the effect from occupational noise exposure on hearing. Pure-tone averages (PTA) of hearing threshold levels simplify the evaluation for audiometric frequencies typically affected by noise. The present study provides reference data of high frequency (HF) PTA over 3, 4 and 6 kHz for a general adult population, aged from 20 to 79 years, not exposed to hazardous occupational noise. The results are presented as statistical distributions of HF PTA values as functions of age, and as prevalence of different degree of HF PTA in the age groups 20-29, 30-39, 40-49, 50-59, 60-69 and 70-79 years.

Journal Article
TL;DR: The linear dose-response relationship agrees with the results of more recent literature evaluations and is not intended to give rise to the question whether in the interest of medical prevention it is reasonable to develop night-time protective policies merely founded on noise levels marking the "statistical" onset of nocturnal wake-up reactions.
Abstract: Night-time wake-up thresholds at noise levels of 60 dB(A) are frequently employed in Germany to establish "noise polluted areas". The criterion is, however, based on an incorrect processing of statistical data gathered from an evaluation of literature performed by Griefahn et al. (1976). This finding has emerged from an extensive revision of the study. Using appropriate statistical methods, maximum levels of under 48 dB(A) are assessed as waking-up thresholds at ear level in sleeping persons, in contrast to maximum levels of 60 dB(A) calculated by Griefahn et al. in 1976. The linear dose-response relationship, which in the course of the revision could be derived from the early publications, agrees with the results of more recent literature evaluations. The present contribution is not intended to give rise to the question whether in the interest of medical prevention it is reasonable to develop night-time protective policies merely founded on noise levels marking the "statistical" onset of nocturnal wake-up reactions. In this context, emphasis is laid on the deformation of the biological rhythm of sleep.

Journal Article
TL;DR: Overall performance was improved in every octave band with smaller associated standard deviations and showed that even with a very modest amount of instruction attenuation performance can be significantly improved.
Abstract: Too often, in spite of the encouragement of those who advocate the removal of noise from the workplace as the preferred solution to noise exposure, hearing protectors are provided as the first line of defence against noise. Unfortunately hearing protectors are too often supplied with no real instruction or education in their use. This degrades their performance considerably. In this project the attenuation performance of one particular model of earplug was compared with and without instructions to test subjects. The instructions given were the most basic as commonly supplied on the plastic packaging containing the plugs. The attenuation performance (SLC80) of the plugs with the instructions was 16 dB greater than without the instructions. Overall performance was improved in every octave band with smaller associated standard deviations. The comparison showed that even with a very modest amount of instruction attenuation performance can be significantly improved.

Journal Article
H Findeis1, E Peters1
TL;DR: Noise immissions with predominant low frequency sound components may exert considerably disturbing effects in dwellings, in particular to sounds which are excitated by transmission of structure-borne noise, and to low frequency sounds emitted by ventilators.
Abstract: Noise immissions with predominant low frequency sound components may exert considerably disturbing effects in dwellings. This applies in particular to sounds which are excitated by transmission of structure-borne noise, and to low frequency sounds emitted by ventilators. Exposed persons usually declare such immissions as being "intolerable" even at very low A-weighted sound levels. If mechanical vibrations in the frequency range below 20 Hz (ground-borne vibrations) affect dwelling rooms, the annoying effects are perceived only by a small portion of exposed individuals as a physical effect. For the most part the immissions are observed as vibratory effects on the building and on objects inside the dwelling. The disturbing effects of vibration frequencies above 20 Hz (structure-borne sound) are determined by the airborne sound field generated inside a particular room and its given surface and extension.

Journal Article
TL;DR: While the weight does not play a major role in styrene ototoxicity, there is a critical period whose duration lasts more than three months and for which the susceptibility to styrene is enhanced.
Abstract: The current experiments were undertaken to determine whether or not styrene-induced hearing loss in the rat depends more on the existence of a critical period between 14 and 21 weeks of age than on body weight. For these purposes, two experiments were carried out with mature Long-Evans rats. In the first experiment, two groups of 5-month old rats, but having different body weight (slim: 314 g vs. fat: 415 g) were exposed to 700 ppm styrene for 4 consecutive weeks, 5 days per week, 6 hours per day. In the second experiment, two groups of rats having the same weight: 345 g, but different ages (14- vs. 21- week old) were exposed to styrene in strictly identical experimental conditions. Auditory sensitivity was tested by recording evoked potentials from the inferior colliculus. Surface preparations of the organ of Corti were also performed to complete the investigation. At the end of the six week recovery period following the styrene exposure, a 7 dB permanent threshold shift (PTS) was obtained with the same age animals regardless of the body weight. Consequently, weight was not a major factor in styrene-induced hearing loss. Age was a more critical factor in determining higher sensitivity to styrene. Indeed, the three months old group had 23.5 dB PTS, whereas the five months old group had only a 7.7 dB PTS at 16 kHz. Thus, a 15 dB difference of PTS was obtained between the rats having the same weight but different age. While the weight does not play a major role in styrene ototoxicity, there is a critical period whose duration lasts more than three months and for which the susceptibility to styrene is enhanced.

Journal Article
TL;DR: Preventative action did not increase in proportion to a corresponding increase in the amount and variety of information provided in connection with hearing health status, and overall awareness of noise and the risks of exposure were increased after both types of hearing test.
Abstract: Research and 'common knowledge' has for many years accepted that education and feedback supplied to individuals during and immediately after workplace health assessments provides valuable information to workers about their health. Further, if more relevant and detailed information could be supplied then awareness and preventative action may increase proportionately. This research carried out with a rural Australian population has shown that preventative action did not increase in proportion to a corresponding increase in the amount and variety of information provided in connection with hearing health status. Two research groups underwent hearing tests, both with pure tone audiometry (PTA) while the second group also underwent otoacoustic emission (OAE) testing. Test results were presented to the subjects at the conclusion of their test session. An analysis of questionnaire responses at six week and twelve months follow up showed that more information did not result in increased preventative action. Barriers seem to exist such that individuals feel that they are not able to effectively act to reduce overall noise exposure. While self-efficacy initially increased, it declined to close to its initial value over the longer period. Other measures such as perceived susceptibility to hearing loss and the benefits of exposure reduction significantly increased and remained at the same increased level after twelve months. So, while overall awareness of noise and the risks of exposure were increased after both types of hearing test there was no increased hearing health benefit due to additional testing and hearing information.


Journal Article
TL;DR: The results show that elderly people suffering from dementia are able to recollect the sounds that had once occupied very important parts of their lives, however, these sounds in themselves are not unusual sounds in their daily lives, suggesting the importance of soundscape design in daily life.
Abstract: In this study, the kinds of sounds recollected by elderly people with dementia were investigated as a first step towards improving their sound environment. Onomatopoeias were presented to elderly people as keys to recollecting sounds, and they told what they imagined from each onomatopoeia. The results are summarized as follows. (1) Generally speaking, sounds from nature, such as the songs of birds and the sound of rain were recollected easily from onomatopoeias, regardless of gender. (2) Sounds of kitchen work were recollected by women only. (3) Sounds from old routines were recollected clearly. (4) Sounds that elicited feelings of nostalgia were also recollected intensely from onomatopoeias. These results show that elderly people suffering from dementia are able to recollect the sounds that had once occupied very important parts of their lives. However, these sounds in themselves are not unusual sounds in their daily lives. This suggests the importance of soundscape design in daily life.

Journal Article
TL;DR: The "Special Assessment of Environment and Health" by the Council of Experts for Environmental Questions of Federal Republic of Germany is presented regarding to it's statements concerning the consequences of aircraft noise during night and it seems necessary to utilize a hierarchical structure of limit values and with interpretation of the term "threshold" as normal physiological reactions.
Abstract: The "Special Assessment of Environment and Health" (SAEH) by the Council of Experts for Environmental Questions of Federal Republic of Germany is presented regarding to it's statements concerning the consequences of aircraft noise during night. Considering the issue of sustainability it is emphasized that lower limit values of the validity of scientific results need to be accepted. As the discussion of the literature shows the statements of the Council are rather vague and warily. This is a question of used parameters of noise effects during the night as well as its interpretation. It seems necessary to utilize a hierarchical structure of limit values and with interpretation of the term "threshold" as normal physiological reactions. More investigations are necessary in this field.