Birgitta Berglund

Aircraft and road traffic noise and children's cognition and health: a cross-national study

BACKGROUNDnExposure to environmental stressors can impair childrens health and their cognitive development. The effects of air pollution, lead, and chemicals have been studied, but there has been less emphasis on the effects of noise. Our aim, therefore, was to assess the effect of exposure to aircraft and road traffic noise on cognitive performance and health in children.nnnMETHODSnWe did a cross-national, cross-sectional study in which we assessed 2844 of 3207 children aged 9-10 years who were attending 89 schools of 77 approached in the Netherlands, 27 in Spain, and 30 in the UK located in local authority areas around three major airports. We selected children by extent of exposure to external aircraft and road traffic noise at school as predicted from noise contour maps, modelling, and on-site measurements, and matched schools within countries for socioeconomic status. We measured cognitive and health outcomes with standardised tests and questionnaires administered in the classroom. We also used a questionnaire to obtain information from parents about socioeconomic status, their education, and ethnic origin.nnnFINDINGSnWe identified linear exposure-effect associations between exposure to chronic aircraft noise and impairment of reading comprehension (p=0.0097) and recognition memory (p=0.0141), and a non-linear association with annoyance (p<0.0001) maintained after adjustment for mothers education, socioeconomic status, longstanding illness, and extent of classroom insulation against noise. Exposure to road traffic noise was linearly associated with increases in episodic memory (conceptual recall: p=0.0066; information recall: p=0.0489), but also with annoyance (p=0.0047). Neither aircraft noise nor traffic noise affected sustained attention, self-reported health, or overall mental health.nnnINTERPRETATIONnOur findings indicate that a chronic environmental stressor-aircraft noise-could impair cognitive development in children, specifically reading comprehension. Schools exposed to high levels of aircraft noise are not healthy educational environments.

Sources and effects of low‐frequency noise

The sources of human exposure to low-frequency noise and its effects are reviewed. Low-frequency noise is common as background noise in urban environments, and as an emission from many artificial sources: road vehicles, aircraft, industrial machinery, artillery and mining explosions, and air movement machinery including wind turbines, compressors, and ventilation or air-conditioning units. The effects of low-frequency noise are of particular concern because of its pervasiveness due to numerous sources, efficient propagation, and reduced efficacy of many structures (dwellings, walls, and hearing protection) in attenuating low-frequency noise compared with other noise. Intense low-frequency noise appears to produce clear symptoms including respiratory impairment and aural pain. Although the effects of lower intensities of low-frequency noise are difficult to establish for methodological reasons, evidence suggests that a number of adverse effects of noise in general arise from exposure to low-frequency noise: Loudness judgments and annoyance reactions are sometimes reported to be greater for low-frequency noise than other noises for equal sound-pressure level; annoyance is exacerbated by rattle or vibration induced by low-frequency noise; speech intelligibility may be reduced more by low-frequency noise than other noises except those in the frequency range of speech itself, because of the upward spread of masking. On the other hand, it is also possible that low-frequency noise provides some protection against the effects of simultaneous higher frequency noise on hearing. Research needs and policy decisions, based on what is currently known, are considered.

Chronic aircraft noise exposure, stress responses, mental health and cognitive performance in school children

BACKGROUNDnPrevious research suggests that children are a high risk group vulnerable to the effects of chronic noise exposure. However, questions remain about the nature of the noise effects and the underlying causal mechanisms. This study addresses the effects of aircraft noise exposure on children around London Heathrow airport, in terms of stress responses, mental health and cognitive performance. The research also focuses on the underlying causal mechanisms contributing to the cognitive effects and potential confounding factors.nnnMETHODSnThe cognitive performance and health of 340 children aged 8-11 years attending four schools in high aircraft noise areas (16 h outdoor Leq > 66 dBA) was compared with children attending four matched control schools exposed to lower levels of aircraft noise (16 h outdoor Leq < 57 dBA). Mental health and cognitive tests were group administered to the children in the schools. Salivary cortisol was measured in a subsample of children.nnnRESULTSnChronic aircraft noise exposure was associated with higher levels of noise annoyance and poorer reading comprehension measured by standardized scales with adjustments for age, deprivation and main language spoken. Chronic aircraft noise was not associated with mental health problems and raised cortisol secretion. The association between aircraft noise exposure and reading comprehension could not be accounted for by the mediating role of annoyance, confounding by social class, deprivation, main language or acute noise exposure.nnnCONCLUSIONSnThese results suggest that chronic aircraft noise exposure is associated with impaired reading comprehension and high levels of noise annoyance but not mental health problems in children.

A principal components model of soundscape perception.

There is a need for a model that identifies underlying dimensions of soundscape perception, and which may guide measurement and improvement of soundscape quality. With the purpose to develop such a model, a listening experiment was conducted. One hundred listeners measured 50 excerpts of binaural recordings of urban outdoor soundscapes on 116 attribute scales. The average attribute scale values were subjected to principal components analysis, resulting in three components: Pleasantness, eventfulness, and familiarity, explaining 50, 18 and 6% of the total variance, respectively. The principal-component scores were correlated with physical soundscape properties, including categories of dominant sounds and acoustic variables. Soundscape excerpts dominated by technological sounds were found to be unpleasant, whereas soundscape excerpts dominated by natural sounds were pleasant, and soundscape excerpts dominated by human sounds were eventful. These relationships remained after controlling for the overall soundscape loudness (Zwickers N(10)), which shows that informational properties are substantial contributors to the perception of soundscape. The proposed principal components model provides a framework for future soundscape research and practice. In particular, it suggests which basic dimensions are necessary to measure, how to measure them by a defined set of attribute scales, and how to promote high-quality soundscapes.

Quantitative and qualitative perceptual analysis of cold dysesthesia and hyperalgesia in fibromyalgia

&NA; Somatosensory perception thresholds, perceived intensity, and quality of perceptions were assessed in 20 women with fibromyalgia syndrome (FMS) and in 20 healthy age‐matched female controls. All patients and controls scaled perceived intensity and described perceived quality of randomized thermal (Thermotest) and tactile (von Frey filaments) stimulation. Perceived intensity was scaled by free‐number magnitude estimation and interindividual comparability was accomplished by Master Scaling. Perceived quality was assessed by choosing verbal descriptors from a list. Thenar was used as a reference for each modality tested. All patients were able to reliably scale perceived intensity at thenar, as well as in pain‐affected body areas. Perception thresholds for cold pain, heat pain, cold‐pain tolerance and heat‐pain tolerance were significantly lower in patients than controls. For cold and tactile stimulation, the master scaled perceived intensities were significantly higher in patients’ pain‐affected areas, whereas for warmth/heat stimulation, the intensities were significantly lower. In the qualitative perceptual analysis the most striking and significant finding was the aberration of cold‐evoked perceptions in all patients: most stimuli in the range of 30–10°C were reported as heat or other paresthetic or dysesthetic perceptions. The perceptual quality of warmth, and of touch, did not differ from the controls. Another aberration was observed in the nociceptive range of thermal and of tactile stimulation as significantly more frequent pain‐related descriptors than in controls. This indicates a general nociceptive facilitation in addition to the lower thermal pain thresholds. The combination of cold hyperesthesia, cold dysesthesia, and multimodal hyperalgesia suggests a selective pathophysiology at a particular level of integration, possibly in the insular cortex. It is suggested that the aberrations revealed by the supraliminal sensory evaluation may be generic for FMS. Particularly, the aberrations established in all patients for perceived quality and intensity in the cold sensory channel may be an additional diagnostic criterion.

A model for the perception of environmental sound based on notice-events

An approach is proposed to shed light on the mechanisms underlying human perception of environmental sound that intrudes in everyday living. Most research on exposure-effect relationships aims at relating overall effects to overall exposure indicators in an epidemiological fashion, without including available knowledge on the possible underlying mechanisms. Here, it is proposed to start from available knowledge on audition and perception to construct a computational framework for the effect of environmental sound on individuals. Obviously, at the individual level additional mechanisms (inter-sensory, attentional, cognitive, emotional) play a role in the perception of environmental sound. As a first step, current knowledge is made explicit by building a model mimicking some aspects of human auditory perception. This model is grounded in the hypothesis that long-term perception of environmental sound is determined primarily by short notice-events. The applicability of the notice-event model is illustrated by simulating a synthetic population exposed to typical Flemish environmental noise. From these simulation results, it is demonstrated that the notice-event model is able to mimic the differences between the annoyance caused by road traffic noise exposure and railway traffic noise exposure that are also observed empirically in other studies and thus could provide an explanation for these differences.

Scaling loudness, noisiness, and annoyance of community noises

The contribution of type and sound levels of community noises to the perception of loudness, noisiness, and annoyance was studied in a laboratory situation. The psychological attributes were precisely defined to the 30 observers, the method of magnitude estimation was used for scaling the attributes, and the scales were calibrated to a common unit of measurement. It was demonstrated that observers in carefully designed laboratory experiments are able to use and produce scales of loudness, noisiness, and annoyance for community noise. The relationships between the attributes were satisfactorily described by linear functions, the parameters being specific to the type of community noise. In general, community noises are judged to be more noisy (or annoying) than loud although the importance of noisiness relative to loudness varies with type of noise as well as loudness level. A linear model is suggested that describes community noises with regard to perceptual attributes. The model states that annoyance and ...

Scaling loudness, noisiness, and annoyance of aircraft noise

The capacity of man to differentiate and scale aircraft noise with regard to three psychological attributes frequently encountered in social survey research on ambient noise was tested. Calibrated scales for the attributes evolved from the two‐step psychological scaling procedure employed. It was demonstrated that observers in carefully designed laboratory situations are able to use and produce scales of loudness, noisiness, and annoyance for aircraft noise. The relationships between the attributes were satisfactorily described by linear functions. In general, aircraft noise was judged to be more annoying than noisy and more noisy than loud. For all three attributes, the psychophysical relationships were best described by power functions with dB(A)max as the physical measure (exponents 0.21–0.24).Subject Classification: 65.50, 65.75.

A comparison of odor perception in smokers, nonsmokers, and passive smokers

The olfactory perception in matched groups of 26 smokers, 26 nonsmokers, and 15 passive smokers was examined psychophysically with two substances, n-butane and pyridine. Different psychophysical functions were obtained from these groups using the method of magnitude estimation. The smokers and passive smokers perceived all concentrations of n-butane to be weaker than did the nonsmokers. In the case of pyridine, a substance in tobacco smoke to which smokers are more exposed, there is an indication of a perceptual deficit similar to loudness recruitment. There were no appreciable differences between smokers and nonsmokers for high concentrations; the sensitivity was less and the psychophysical functions steeper for smokers than nonsmokers for relatively low concentrations. The results are evaluated in terms of information about the subjects response criteria, and the authors consider the possibility of sensory deficit versus habituation.

Invariance of odor strength with sniff vigor: an olfactory analogue to size constancy.

Previous evidence has shown that detection threshold in humans and olfactory neural discharge rate in animal preparations both depend on flow rate of odorous vapor. But no data have been reported that show the effects of flow rate in humans on perceived odor strength at suprathreshold intensities. Subjects learned to inspire at two flow rates, one twice as great as the other, by adjusting (on a cathode ray tube) the transduced trace of a sniff-produced pressure change to match either of two target contours. They then made magnitude estimations of odor strength, while producing either weak or strong sniffs, for odorants presented over a wide range of concentrations via a specially designed sniff-bottle system. The odorant, diluted in diethyl phthalate, was n-butanol in two experiments and n-amyl acetate in two others. Subject-controlled flow rate had no effect on odor strength for either odorant. There was an apparent contradiction between these data and those on neural discharge rate that may, however, be resolved by adopting an odor constancy model: When sniff intensity varies during the olfactory exploration of an odor source, information about the rate at which odorant molecules are established at the receptor site is combined with information about sniff vigor so that the resulting percept is of invariant odor strength.