Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “NOISE”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 199 records · Page 11Linked to original sources
PubMed1990

Masking of tone bursts by modulated noise in normal, noise-masked normal, and hearing-impaired listeners.

Threshold of 4.6-ms tone bursts was measured in quiet and in the presence of a 100% sinusoidally amplitude-modulated speech-shaped noise. For the modulated-noise conditions, the onset of the tone burst coincided either with the maximum or the minimum modulator amplitude. The difference in these two masked thresholds provided an indication of the psychoacoustic modulation depth, or the modulation depth preserved within the auditory system. Modulation frequencies spanning the modulation spectrum of speech (2.5 to 20 Hz) were examined. Tone bursts were 500, 1400, and 4000 Hz. Subjects included normal listeners, normal listeners with a hearing loss simulated by high-pass noise, and hearing-impaired listeners having high-frequency sensorineural hearing loss. Normal listeners revealed a psychoacoustic modulation depth of 30-40 dB for the lowest modulation frequencies which decreased to about 15 dB at 20 Hz. The psychoacoustic modulation depth was decreased in the normal listeners with simulated hearing loss and in the hearing-impaired listeners. There was general agreement in the data, however, for the latter two groups of listeners suggesting that the normal listeners with hearing loss simulated by an additional masking noise provided a good representation of the performance of hearing-impaired listeners on this task.

Adult↗
PubMed2006

A noise-sensor light alarm reduces noise in the newborn intensive care unit.

This one-group pre-post test design was to evaluate sound distribution and sudden peak noise frequencies (SPNs) and the associated events after using a noise-sensor light alarm in a tertiary neonatal intensive care unit (NICU). The alarm is activated as the sound level reaches>or=65 A-weighted decibel (dBA). The environmental sound level was monitored continuously for a period of 1 week before and 1 month after using the alarm. The mean sound level in the incubator of patients receiving ventilator support before and after using the device were 58.0+/-0.6 and 56.4+/-0.7 dBA (t=8.619; p<0.001), whereas those at the radiant heated bed were 58.0+/-2.4 and 58.1+/-2.0 dBA (t=0.715; p=0.476). The percentage of observation time of sound levels<58 dBA increased by 28% in the incubator and 4% at the radiant heated bed (p<0.001). Episodes of SPN decreased from 630 to 185 times/d in the incubator and from 2069 to 748 times/d at the radiant heated bed after using the device. The noise-sensor light alarm effectively reduces sound level and episodes of SPN in the NICU. This may alleviate stress of noise for newborns with critical illness.

Environmental Exposure↗
PubMedDate not supplied

Traffic noise and cardiovascular risk: the Speedwell study, first phase. Outdoor noise levels and risk factors.

As part of the Speedwell study, traffic noise exposure and risk factors for ischemic heart disease were studied in a sample of 2,348 men whose ages ranged from 45 to 63 y. The road traffic noise emission level, Leq, ranged between 51 and 70 dB(A) (6-22 h, 10-m distance). Significant associations were found between noise and potential ischemic heart disease risk factors, including total triglycerides, platelet count, plasma viscosity, glucose (increases), and systolic and diastolic blood pressure (decreases). Not all results support the hypothesis that traffic noise increases ischemic heart disease risk. The results were controlled for a number of potential confounding factors.

Automobiles↗
PubMedDate not supplied

Change in rapid eye movement (REM) sleep in response to exposure to all-night noise and transient noise.

Several experiments conducted by the authors revealed certain characteristic changes in stage rapid-eye-movement sleep in response to noise exposure. Continuous and all-night exposure to noise first decreased the percentage of rapid-eye-movement stage at Leg 45dBA. In contrast, the threshold of shifts from the rapid-eye-movement stage in response to intermittent noise was higher than thresholds noted for slow-wave sleep or stage-2 sleep. We concluded that these results indicated that a silent environment is required to maintain the duration of rapid-eye-movement sleep, even though rapid-eye-movement sleep is stable and is not influenced easily by noise.

Adult↗
PubMed2002

Music is as distracting as noise: the differential distraction of background music and noise on the cognitive test performance of introverts and extraverts.

Previous research has found that introverts' performance on complex cognitive tasks is more negatively affected by distracters, e.g. music and background television, than extraverts' performance. This study extended previous research by examining whether background noise would be as distracting as music. In the presence of silence, background garage music and office noise, 38 introverts and 38 extraverts carried out a reading comprehension task, a prose recall task and a mental arithmetic task. It was predicted that there would be an interaction between personality and background sound on all three tasks: introverts would do less well on all of the tasks than extraverts in the presence of music and noise but in silence performance would be the same. A significant interaction was found on the reading comprehension task only, although a trend for this effect was clearly present on the other two tasks. It was also predicted that there would be a main effect for background sound: performance would be worse in the presence of music and noise than silence. Results confirmed this prediction. These findings support the Eysenckian hypothesis of the difference in optimum cortical arousal in introverts and extraverts.

Adolescent↗
PubMed1985

Occupational noise exposure, noise-induced hearing loss, and the epidemiology of high blood pressure.

The role of noise exposure in the etiology of high blood pressure is unclear. A cross-sectional study of occupational noise exposure and high blood pressure was conducted in March 1981-August 1982 in a group of blue-collar workers from a noisy (greater than or equal to 89 dBA) and a less noisy plant (less than 81 dBA). There were 197 randomly sampled men from the noisier plant and 169 from the comparison factory. Clinical examinations, audiograms and a psychologic inventory were conducted. Body mass index, alcohol intake, and family history of hypertension were comparable for the two groups. There was no difference in mean systolic or diastolic blood pressure between workers in the two plants. There was, however, a strong relationship between severe noise-induced hearing loss (greater than or equal to 65 dBA loss at 3, 4, or 6 k Hz) and high blood pressure (greater than or equal to 90 mmHg diastolic or taking blood pressure medication) in the 56+ age group in both plants after adjusting for risk factors (p less than 0.02). Multiple regression analysis revealed that in the noisier plant, body mass index, severe noise-induced hearing loss, and noisy hobbies explained a significant amount of the variation in diastolic pressure (p less than 0.05) R2 = 0.19. This suggests that there may be a population at increased risk for hearing loss and high blood pressure.

Adult↗
PubMed2001

Noise suppression by noise.

We have analyzed the interplay between an externally added noise and the intrinsic noise of systems that relax fast towards a stationary state, and found that increasing the intensity of the external noise can reduce the total noise of the system. We have established a general criterion for the appearance of this phenomenon and discussed two examples in detail.

Models, Theoretical↗
PubMed2004

Relationship between exposure to multiple noise sources and noise annoyance.

Relationships between exposure to noise [metric: day-night level (DNL) or day-evening-night level (DENL)] from a single source (aircraft, road traffic, or railways) and annoyance based on a large international dataset have been published earlier. Also for stationary sources relationships have been assessed. Here the annoyance equivalents model concerning noise annoyance from combined sources and the underlying assumptions are presented. The model first translates the noise from the individual sources into the equally annoying sound levels of a reference source, road traffic, and then sums these levels giving total level L. The annoyance from the combined sources is found by substituting exposure L in the road traffic exposure-annoyance relationship. The most important assumption, independence of the contributions of the sources, is discussed. It appears that independence will be violated substantially only due to the effect of the presence or absence of a quiet side of building which is not incorporated in the model. For use in practice the application of the model is broken down in five steps. The step by step procedure can be used for the assessment of the total noise level and the associated total annoyance on the basis of the DNL or DENL values of the individual sources.

Acoustics↗
PubMed1994

Development of the Hearing in Noise Test for the measurement of speech reception thresholds in quiet and in noise.

A large set of sentence materials, chosen for their uniformity in length and representation of natural speech, has been developed for the measurement of sentence speech reception thresholds (sSRTs). The mean-squared level of each digitally recorded sentence was adjusted to equate intelligibility when presented in spectrally matched noise to normal-hearing listeners. These materials were cast into 25 phonemically balanced lists of ten sentences for adaptive measurement of sentence sSRTs. The 95% confidence interval for these measurements is +/- 2.98 dB for sSRTs in quiet and +/- 2.41 dB for sSRTs in noise, as defined by the variability of repeated measures with different lists. Average sSRTs in quiet were 23.91 dB(A). Average sSRTs in 72 dB(A) noise were 69.08 dB(A), or -2.92 dB signal/noise ratio. Low-pass filtering increased sSRTs slightly in quiet and noise as the 4- and 8-kHz octave bands were eliminated. Much larger increases in SRT occurred when the 2-kHz octave band was eliminated, and bandwidth dropped below 2.5 kHz. Reliability was not degraded substantially until bandwidth dropped below 2.5 kHz. The statistical reliability and efficiency of the test suit it to practical applications in which measures of speech intelligibility are required.

Acoustic Stimulation↗
PubMedDate not supplied

Subclinical vestibular pathology in patients with noise-induced hearing loss from intense impulse noise.

Sixty patients with varying degrees of noise-induced hearing loss (NIHL) after long-term exposure to intense impulse noise from firearms, but without manifest clinical symptoms of vestibular pathology, were tested for body sway using a stable platform. The results were compared with those from 115 healthy referents examined in the same way. Subjects with NIHL showed significantly more body sway, estimated as movement of the centre of gravity in the horizontal plane, than did the referents. Subjects with more severe NIHL showed more sway than subjects with milder acoustic trauma. The results show that body sway is increased in patients with NIHL from exposure to impulse noise of high intensity in a way suggesting an exposure-effect relationship. This suggests subclinical disturbances of the vestibular system in these patients. The underlying mechanism may be simultaneous mechanical damage to both the cochlear and vestibular partitions by intense impulse noise.

Firearms↗
PubMed2001

Noise pollution: a study of noise levels in the operation theatres of a general hospital during various surgical procedures.

Noise, defined as any unwanted or undesirable sound, is a known environmental pollutant and health hazard. Sound levels during the entire surgical procedures were measured in the operation theatres (OTs) of a general hospital in Delhi, using a sound level meter, B & K 2209, on the dB(A) scale. The sound levels were found to be higher as compared to the recommended international standands. The noise was contributed mainly by doors, trolleys, equipment and alarms and the incessant conversation among the operation theatre (OT) staff. It is well documented that noise is stressful eliciting changes in the autonomic nervous system, impairing mental faculties and producing masking that could affect the staff and the conscious patient alike, leading to decreased work performance and increased anxiety respectively. Better acoustic designing and maintenance of equipment together with an increased awareness of the OT staff towards this vital factor of work environment may effectively reduce the noise pollution in OTs.

Humans↗
PubMedDate not supplied

Aircraft noise and times of day: possibilities of redistributing and influencing noise exposure.

Disturbing effects of aircraft noise depend on the time of day at which the sound sources emerge. The reason can be seen in different human activities which vary qualitatively throughout the day. Especially in the evening and during the night people are more sensitive against noise induced disturbances which is a result of several field studies. Additionally there exists empirical evidence that human performance behaviour profits by keeping the night period free of sound exposure. As a consequence of these findings it is discussed whether the existing air traffic should be rescheduled to the daytime. It is argued that not only noise rescheduling needs to be considered, but also the spatial redistribution of air traffic volume. In using a mix of rescheduling techniques and administrative possibilities, significant reductions of aircraft noise exposure can be achieved.

Aircraft↗
PubMed1990

[Effectiveness of anti-noise lining, ear muffs and their combination under the effect of high-level impulse noise].

The article contains a description of a new technique for assessment of the effectiveness of noise-protecting bushes and era-flaps against the intensive impulse noise of shooting a 105 mm cannon and heavy grenade cup discharges. The technique envisages a simultaneous measurement of the maximal noise pressure levels with a common microphone from the inside under the ear-flap. It was indicated that a simultaneous use of bushes and protecting ear-flaps was more effective, but still less than a summation effect of their individual noise-protecting properties.

Ear Protective Devices↗
PubMed1995

Measurement of the airborne noise and the noise at the operator's position emitted by the ECOTRAC V-1033 F forest tractor.

The paper reports on the measurement procedure and results of measurements of the airborne noise emitted by the ECOTRAC V-1033 F forest tractor. The measurements were carried out in accordance with the International Standards ISO 4872 and 362 for the stationary test condition. The paper further reports on noise measurements at the tractor operator's position conducted in accordance with the International Standards ISO 5131 and 6394. All measurements were performed using the Bruel & Kjaer 4165 type microphone and the 2209 type sound level meter from the same manufacturer. According to ISO 4872, 6393 and 362 the noise level did not exceed the limit values. However, the noise level at the operator's position at full load and at nominal load exceeded the limits. Measures to be undertaken should aim at protecting the driver and improving the cab characteristics.

Forestry↗
PubMed1987

Non-auditory effects of noise in industry. IV. A field study on industrial noise and blood pressure.

Audiometry and casual blood pressure measurements were carried out among industrial workers exposed to noise levels exceeding 80 dB(A). Workers with long-term noise exposure had increased blood pressure, after correction for age. Only a weak correlation was observed between noise-induced hearing loss and the corrected blood pressure. The influence of other working conditions and of the relative body weight could not be evaluated.

Blood Pressure↗
PubMed1980

Impulse noise - measurement and assessment of the risk of noise induced hearing loss.

This work was an attempt to characterize the various types of noise impulses in terms of their excitation mechanisms. It also studied how impulse noise affects the Leq, on the basis of measurements made at a number of workplaces. The paper concludes with a review of the incidence of hearing damage among groups of personnel exposed to different types of noise in the building industry.

Hearing Loss, Noise-Induced↗
PubMed1991

A coupled resonator model of the detection of nuclear magnetic resonance: radiation damping, frequency pushing, spin noise, and the signal-to-noise ratio.

Magnetic resonance involves two coupled resonating systems: the spins and the tuned receiver coil. We simulate the spin system by an equivalent electrical resonator. An analysis of coupled resonators leads to a straightforward derivation of properties such as radiation damping, frequency pushing, and spin noise. The theory is applied to recent experiments (M. Guéron and J. L. Leroy, J. Magn. Reson. 85, 209-215 (1989]. The sensitivity of the spin noise experiment is shown to be T2/tau 0, where 1/tau 0 is the rate of radiation damping. This result leads directly to a fundamental formulation of the usual signal-to-noise ratio, (SNR)2 = (m0 B/tau 0)/(4Fk theta delta v), where m0 is the equilibrium magnetic moment, theta is the temperature, and F is the noise figure of the receiver. An equivalent electrical resonator can also be used to describe the active medium of masers.

Computer Simulation↗
PubMedDate not supplied

Image signal-to-noise ratio and noise variance estimation using autoregressive model.

During the last three decades, several techniques have been proposed for signal-to-noise ratio (SNR) and noise variance estimation in images, with different degrees of success. Recently, a novel technique based on the statistical autoregressive model (AR) was developed and proposed as a solution to SNR estimation in scanning electron microscope (SEM) image. In this paper, the efficiency of the developed technique with different imaging systems is proven and presented as an optimum solution to image noise variance and SNR estimation problems. Simulation results are carried out with images like Lena, remote sensing, and SEM. The two image parameters, SNR and noise variance, are estimated using different techniques and are compared with the AR-based estimator.

Journal Article↗