Functional analysis of stereotypical ear covering in a child with autism.
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We studied stereotypical ear covering in a child with autism. Results of a descriptive analysis were inconclusive but revealed a correlation between ear covering and another child's screaming. An analogue functional analysis showed that ear covering was emitted only when the screaming was present. (+info)
Morphological effects in the mouse myocardium after methylenedioxymethamphetamine administration combined with loud noise exposure.
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Early toxicity occurring during or immediately after 3,4-methylenedioxymethamphetamine (MDMA, or "ecstasy") administration has not been investigated in detail, although in humans it is responsible for marked side effects, and even death. Acute toxicity induced by MDMA produces rhabdomyolysis involving the myocardium (myocytolysis). Cardiac symptoms, such as tachycardia, hypertension, and arrhythmia, are present to a variable extent in humans abusing ecstasy. In most cases, this substance is abused in the presence of loud noise, which may affect the myocardium. Despite the frequency of the concomitant exposure to ecstasy and loud noise, and the similarities between the early side effects of these two agents, to our knowledge no study has investigated the role of loud noise in modulating MDMA toxicity. Therefore, in the present study, we evaluated whether cardiac effects of MDMA administration following a typical "binging" pattern are enhanced by concomitant exposure to loud noise. We selected low doses of MDMA in order to avoid gross morphological alterations, or lesions detectable under light microscopy. The myocardial alterations observed were visible only at the ultrastructural level. We found a dramatic enhancement of alterations in the mouse heart upon MDMA administration during loud noise exposure. Remarkably, this enhancement was evident both as a decrease in the threshold dose of MDMA necessary to alter the myocardial ultrastructure, and as an increase in myocardial alterations produced by a higher dose of MDMA. (+info)
Conditions of application of repeated transcranial magnetic stimulation to rats may mask the effects of the treatment.
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Rats of sham repeated transcranial magnetic stimulation (rTMS) group, kept in noisy room and transiently immobilized (5 min) for 12 consecutive days, showed similar inhibition of body weight gain, increase in exploratory locomotor activity, and elevation of motor response to apomorphine as rats undergoing magnetic stimulation of the brain, and had only slightly lower response in apomorphine stereotypy. Some of the responses ascribed to antidepressant action of rTMS in animal experiment may be due to environmental conditions, and not alternating magnetic field passing the brain. (+info)
Noise in the postanaesthesia care unit.
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BACKGROUND: Although the postanaesthesia care unit (PACU) can be noisy, the effect of noise on patients recovering from anaesthesia is unknown. We studied the sources and intensity of noise in the PACU and assessed its effect on patients' comfort. METHODS: We measured noise in a five-bed PACU with a sound level meter. Noise levels were obtained using an A-weighted setting (dBA) and peak sound using a linear scale (dBL). Leq (average noise level at 5-s intervals), maximum Leq (LeqMax), minimum Leq (LeqMin) and noise peaks (Lpc) were calculated. During recording, an independent observer noted the origin of sounds from alarms and noise above 65 dB intensity (P65dB). Two hours after leaving the PACU, patients were asked about their experience and to rank their complaints on a visual analogue scale (VAS) using unstructured and structured questionnaires. RESULTS: We made 20,187 measurements over 1678 min. The mean Leq, LeqMax and LeqMin were 67.1 (SD 5.0), 75.7 (4.8) and 48.6 (4.1) dBA respectively. The mean Lpc was 126.2 (4.3) dBL. Five per cent of the noise was at a level above 65 dBA. Staff conversation caused 56% of sounds greater than 65 dB and other noise sources (alarm, telephone, nursing care) were each less than 10% of these sounds. Five patients reported disturbance from noise. There was no significant difference in Leq measured for patients who found the PACU noisy and those who did not [59.5 (3.1) and 59.4 (2.4) dBA respectively]. Stepwise multiple logistic regression indicated that only pain was associated with discomfort. CONCLUSIONS: Even though sound in the PACU exceeded the internationally recommended intensity (40 dBA), it did not cause discomfort. Conversation was the most common cause of excess noise. (+info)
Variation in inter-animal susceptibility to noise damage is associated with alpha 9 acetylcholine receptor subunit expression level.
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Large intersubject variabilities in acoustic injury are known to occur in both humans and animals; however, the mechanisms underlying such differences are poorly understood. The olivocochlear efferent system has been hypothesized to play a significant role in protecting the cochlea from noise overexposure. In this study, we demonstrate that a newly developed test for determining average efferent system strength can predict intersubject variations in acoustic injury. In addition, the intersubject variability in cochlear expression of the alpha9 subunit of the nicotinic acetylcholine receptor was found to be proportional to an animals average efferent strength. Therefore, the inter-animal variability in the alpha9-containing acetylcholine receptor expression may be one mechanism contributing to the inter-animal variability in acoustic injury. (+info)
Ambient neighbourhood noise and children's mental health.
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OBJECTIVES: To investigate the relation between typical ambient noise levels (highway, rail, road) and multiple mental health indices of school children considering psychosocial and biological risk factors as potential moderators. METHODS: With a two stage design strategy (representative sample and extreme sample) two cross sectional samples (n=1280; n=123) of primary school children (age 8-11) were studied. Individual exposure to noise at home was linked with two indices of mental health (self reporting by the child on a standard scale and rating by the teacher of classroom adjustment on a standard scale). Noise exposure was modelled firstly according to Austrian guidelines with the aid of a geographical information system and then calibrated and corrected against measurements from 31 locations. Information on potential confounders and risk factors was collected by mothers and controlled in regression modelling through a hierarchical forward stepping procedure. Interaction terms were also analysed to examine subgroups of children at risk-for example, low birth weight and preterm birth. RESULTS: Noise exposure was significantly associated in both samples with classroom adjustment ratings. Child self reported mental health was significantly linked to ambient noise only in children with a history of early biological risk (low birth weight and preterm birth). CONCLUSIONS: Exposure to ambient noise was associated with small decrements in children's mental health and poorer classroom behaviour. The correlation between mental health and ambient noise is larger in children with early biological risk. (+info)
Detection of large interaural delays and its implication for models of binaural interaction.
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The interaural time difference (ITD) is a major cue to sound localization along the horizontal plane. The maximum natural ITD occurs when a sound source is positioned opposite to one ear. We examined the ability of owls and humans to detect large ITDs in sounds presented through headphones. Stimuli consisted of either broad or narrow bands of Gaussian noise, 100 ms in duration. Using headphones allowed presentation of ITDs that are greater than the maximum natural ITD. Owls were able to discriminate a sound leading to the left ear from one leading to the right ear, for ITDs that are 5 times the maximum natural delay. Neural recordings from optic-tectum neurons, however, show that best ITDs are usually well within the natural range and are never as large as ITDs that are behaviorally discriminable. A model of binaural crosscorrelation with short delay lines is shown to explain behavioral detection of large ITDs. The model uses curved trajectories of a cross-correlation pattern as the basis for detection. These trajectories represent side peaks of neural ITD-tuning curves and successfully predict localization reversals by both owls and human subjects. (+info)
A health impact assessment model for environmental changes attributable to development projects.
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STUDY OBJECTIVE: European Union legislation requires large industrial and civil development projects to undergo environmental impact assessment. The study objective was to identify environmental health risk estimates for these developments from the epidemiological literature and to develop, and apply these within, a mathematical health impact assessment model. DESIGN AND RESULTS: In the UK, good practice guidelines have set out environmental issues to be considered in development projects, but little attention is given to direct health effects. Broad quantifiable risks were identified for four-air, chemicals, noise, and road traffic-of 14 standard environmental effects. A mathematical model was constructed that is based on people moving between different health states over their lifetime. Age related hazard functions are applied to cause specific measures of mortality and morbidity. A hypothetical example for a development creating air and chemical pollutants is given. CONCLUSIONS: A mathematical model applying epidemiological risks to an exposed population can provide quantification of environmental health effects. The approach may in future find application during project development, and by public health regulatory authorities for environmental health impact assessment. (+info)