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PubMed1992

Noise-induced psychogenic tremor associated with post-traumatic stress disorder.

Tremors in post-traumatic stress disorders have not been previously well characterized. A 67-year-old man has a 46-year history of a noise-induced exaggerated startle reflex followed by a large amplitude rest, postural and kinetic tremor that may persist for up to 3 days. This tremor is superimposed on a continuous mild organic postural/kinetic tremor whose electrophysiological characteristics are different from those of the overlying tremor. We attribute the exaggerated startle reflex and the noise-induced tremor to Post-Traumatic Stress Disorder (PTSD) and postulate a psychogenic origin for the noise-induced tremor. The patient also believes the noise-induced tremor to be psychologically based and to be produced by the fear and anxiety he experiences when he hears loud, unexpected noises. The sudden onset of the noise-induced tremor, its intermittent character, its temporary disappearance on distraction despite the patient's inability to suppress it, inconsistencies in handwriting and figure drawing, and the fact that the noise-induced tremor is stimulus specific and persists long after the offending stimulus (noise) is no longer present all suggest a tremor of psychogenic origin.

Accidents↗
PubMed1984

Daytime noise and subsequent night sleep in man.

The effects of daytime noise on recovery processes during subsequent undisturbed night sleep were studied in six healthy men (21-27 years), exposed to 80 dB (A) pink noise 8 h per day for 2 days. Sleep EEG, ECG, and respiration were recorded in the laboratory for five consecutive nights: two baseline nights, two nights following noise stimulation, and again one baseline night. Additionally questionnaire data were collected, reflecting a subjective impairment of the recovery function of sleep after noise exposure. EEG sleep data of the first post-noise night showed an increase in slow wave sleep with a simultaneous decrease in stage 2 sleep. During the second post-noise night these changes were less prominent. Three subjects additionally showed an instability in the sleep course coinciding with elevated heart and respiration rates. However, altogether the autonomic parameters were not clearly affected by the noise exposure. The findings support the assumption that strong daytime noise may interfere with subsequent sleep processes.

Adult↗
PubMedDate not supplied

[Burdens due to noise and air pollution in residents of areas near streets with heavy traffic].

The residents of different streets with varying traffic density and building density were questioned about annoyance due to traffic noise and air pollution. Frequency and extent of annoyance felt, effects of immissions on such living aspects as recreation, or communication, and also the reactions to the disturbance felt (such as closing windows and taking sleeping pills) were investigated. Noise levels as well as particulate matter and gaseous air pollutant concentrations were measured along the streets under investigation. The evaluation of 1300 questionaires showed that reactions to noise were different in different quarters although noise levels were the same. In general, about 40% of residents were heavily disturbed during daytime when the noise level Leq was around 65 dB(A); while for the same noise level at night about 55% reported to be heavily disturbed. Strong correlations were also obtained between annoyance due to noise and that due to air pollution. The results show that annoyance felt is dependent not only on the measured noise levels and/or air pollution concentrations, but that there do exist interactions between the residential quarters and annoyance. These interactions should be considered while fixing the limits and standards.

Air Pollution↗
PubMed2003

[The Oldenburg children's rhyme test during speech simulating noise disturbance (Regensburg variant). Modification of the test and normal values for the ages 7-10 years].

OBJECTIVE: Of the German language speech audiometry tests used for children, only the Oldenburg children's rhyme test is constructed to allow measurements in noise. Unfortunately, no reference values exist for such measurements. Many of children admitted to test speech discrimination in noise are suspected of suffering from central auditory processing disorders and/or attention deficits. Thus, the objective of the present study is the development of a speech-in-noise test that focuses the children's attention on the target words. DESIGN: A speech-simulating noise was added to the Oldenburg children's rhyme test and the discrimination function was estimated. First, the total power of all target words was equalised and the total power of the noise adjusted to obtain a constant signal-to-noise ratio (SNR) for all target words. Second, speech and noise were presented binaurally with headphones. Speech was presented at 65 dB SPL and the noise level varied to obtain SNRs of 0, -5 and -10 dB SN. A total of 55 normal children, 7-10 years of age, were also tested. RESULTS: Mean speech discrimination was 91+/-7% at 0 dB SN, 75+/-11% at -5 dB SN and 55+/-14% at -10 dB SN. The discrimination function results in a speech reception threshold (SRT) of -10.9 dB SN and a maximum slope of 4.95%/dB SN. CONCLUSION: The "Regensburg" variation of the "Oldenburg children's rhyme test" was easily feasible in all tested children. The results can be used as normative data for children between 7 and 10 years.

Age Factors↗
PubMed1997

Noise stress does not modulate effects of smoking/nicotine on beta-endorphin, cortisol, ACTH, glucose, and mood.

Noise-dependent effects of smoking multiple cigarettes on subjective state and blood concentrations of ACTH, beta-endorphin, cortisol, and glucose were assessed in a repeated measures design where noise level (high versus minimal) was crossed with nicotine dose (quasi-ad lib own brand versus 1.0 mg FTC nicotine machine-delivered dose versus 0.05 mg FTC nicotine machine-delivered dose). Cortisol and ACTH were increased by nicotine, but not by noise and there was no noise by dose interaction. In contrast, nicotine did not increase beta-endorphin in either noise condition and there was no dose by noise interaction for beta-endorphin. However, noise was associated with a modest increase in beta-endorphin. The effects of nicotine on blood glucose varied as a function of the number of cigarettes smoked. However, the effects of nicotine on glucose, hormones, and subjective state did not vary as a function of noise stress.

Adrenocorticotropic Hormone↗
PubMed2005

Hearing in fishes under noise conditions.

Our current knowledge on sound detection in fishes is mainly based on data acquired under quiet laboratory conditions. However, it is important to relate auditory thresholds to background noise in order to determine the signal-detecting abilities of animals in the natural environment. We investigated the influence of two noise levels within the naturally occurring range on the auditory sensitivity of two hearing specialists (otophysines) and a hearing generalist. Audiograms of the goldfish Carassius auratus, the lined Raphael catfish Platydoras costatus and the pumpkinseed sunfish Lepomis gibbosus (hearing generalist) were determined between 200 and 4000 Hz (100-800 Hz for L. gibbosus) under laboratory conditions and under continuous white noise by recording auditory evoked potentials (AEPs). Baseline thresholds showed greatest hearing sensitivity around 500 Hz in goldfish and catfish and at 100 Hz in the sunfish. Continuous white noise of 110 dB RMS elevated the thresholds by 15-20 dB in C. auratus and by 4-22 dB in P. costatus. White noise of 130 dB RMS elevated overall hearing thresholds significantly in the otophysines by 23-44 dB. In the goldfish, threshold did not shift at 4 kHz. In contrast, auditory thresholds in the sunfish declined only at the higher noise level by 7-11 dB. Our data show that the AEP recording technique is suitable for studying masking in fishes, and that the occurrence and degree of the threshold shift (masking) depend on the hearing sensitivity of fishes, the frequency, and noise levels tested. The results indicate that acoustic communication and orientation of fishes, in particular of hearing specialists, are limited by noise regimes in their environment.

Acoustic Stimulation↗
PubMed2006

The effect of Gaussian noise on the threshold, dynamic range, and loudness of analogue cochlear implant stimuli.

The deliberate addition of Gaussian noise to cochlear implant signals has previously been proposed to enhance the time coding of signals by the cochlear nerve. Potentially, the addition of an inaudible level of noise could also have secondary benefits: it could lower the threshold to the information-bearing signal, and by desynchronization of nerve discharges, it could increase the level at which the information-bearing signal becomes uncomfortable. Both these effects would lead to an increased dynamic range, which might be expected to enhance speech comprehension and make the choice of cochlear implant compression parameters less critical (as with a wider dynamic range, small changes in the parameters would have less effect on loudness). The hypothesized secondary effects were investigated with eight users of the Clarion cochlear implant; the stimulation was analogue and monopolar. For presentations in noise, noise at 95% of the threshold level was applied simultaneously and independently to all the electrodes. The noise was found in two-alternative forced-choice (2AFC) experiments to decrease the threshold to sinusoidal stimuli (100 Hz, 1 kHz, 5 kHz) by about 2.0 dB and increase the dynamic range by 0.7 dB. Furthermore, in 2AFC loudness balance experiments, noise was found to decrease the loudness of moderate to intense stimuli. This suggests that loudness is partially coded by the degree of phase-locking of cochlear nerve fibers. The overall gain in dynamic range was modest, and more complex noise strategies, for example, using inhibition between the noise sources, may be required to get a clinically useful benefit.

Adult↗
PubMed2000

Rate representation of tones in noise in the inferior colliculus of decerebrate cats.

Neurons in the central nucleus of the inferior colliculus (ICC) of decerebrate cats show three major response patterns when tones of different frequencies and sound-pressure levels (SPLs) are presented to the contralateral ear. The frequency response maps of type I units are uniquely defined by a narrow excitatory area at best frequency (BF: a unit's most sensitive frequency) and surrounding inhibition at higher and lower frequencies. As a result of this receptive field organization, type I units exhibit strong excitatory responses to BF tones but respond only weakly to broadband noise (BBN). These response characteristics predict that type I units are well suited to encode narrowband signals in the presence of background noise. To test this hypothesis, the dynamic range properties of ICC unit types were measured under quiet conditions and in multiple levels of continuous noise. As observed in previous studies of the auditory nerve and cochlear nucleus, type I units showed upward threshold shifts and discharge rate compression in background noise that partially degraded the dynamic range properties of neural representations at high noise levels. Although the other two unit types in the ICC showed similar trends in threshold shift and noise compression, their ability to encode auditory signals was compromised more severely in increasing noise levels. When binaural masking effects were simulated, only type I units showed an enhanced representation of spatially separated signals and maskers that was consistent with human perceptual performance in independent psychoacoustic observations. These results support the interpretation that type I units play an important role in the auditory processing of narrowband signals in background noise and suggest a physiological basis for spatial factors that govern signal detection under free-field listening conditions.

Animals↗
PubMed2006

Effect of Triphala on oxidative stress and on cell-mediated immune response against noise stress in rats.

Stress is one of the basic factors in the etiology of number of diseases. The present study was aimed to investigate the effect of Triphala (Terminalia chebula, Terminalia belerica and Emblica officinalis) on noise-stress induced alterations in the antioxidant status and on the cell-mediated immune response in Wistar strain male albino rats. Noise-stress employed in this study was 100 dB for 4 h/d/15 days and Triphala was used at a dose of 1 g/kg/b.w/48 days. Eight different groups of rats namely, non-immunized: control, Triphala, noise-stress, Triphala with noise-stress, and corresponding immunized groups were used. Sheep red blood cells (5 x 10(9) cells/ml) were used to immunize the animals. Biochemical indicators of oxidative stress namely lipid peroxidation, antioxidants superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), ascorbic acid in plasma and tissues (thymus and spleen) and SOD, GPx and corticosterone level in plasma were estimated. Cell-mediated immune response namely foot pad thickness (FPT) and leukocyte migration inhibition (LMI) test were performed only in immunized groups. Results showed that noise-stress significantly increased the lipid peroxidation and corticosterone level with concomitant depletion of antioxidants in plasma and tissues of both non-immunized and immunized rats. Noise-stress significantly suppressed the cell-mediated immune response by decreased FPT with an enhanced LMI test. The supplementation with Triphala prevents the noise-stress induced changes in the antioxidant as well as cell-mediated immune response in rats. This study concludes that Triphala restores the noise-stress induced changes may be due to its antioxidant properties.

Animals↗
PubMed1993

EtOH self-administration in anticipation of noise stress in C57BL/6J mice.

C57BL/6J mice were studied for self-administration of ethanol (EtOH) during a signal period that preceded delivery of an environmental stressor (noise) in the home cage. Animals were given 5 weeks of conditioning in which a 5-min period of 75-dB pulsed noise (SIGNAL) preceded a 20-min period of more intense, 90-dB pulsed noise (NOISE) five times daily. EtOH (10% w/v) was then provided in a choice procedure, and drink tube contacts were monitored by computer. Mice that had received the 5 weeks of SIGNAL and NOISE pairings showed an increase in EtOH-seeking behavior, as reflected in EtOH tube contacts during the SIGNAL period. The increase was significant as compared to contacts during baseline or QUIET periods and also as compared to contacts during the same period for control (Ctrl) mice that had received only the 75-dB SIGNAL during conditioning. A subsequent test for passive avoidance confirmed that the 75-dB SIGNAL was aversive for mice that had received noise conditioning but not for Ctrl mice. In sum, the results were in accord with a priori predictions that mice would not show increased EtOH tube contacts during occurrence of intense noise itself but would show increased contacts during the signal that preceded noise. These results were interpreted as preliminary evidence that C57BL/6J mice show self-administration of EtOH in anticipation of an environmental stressor.

Animals↗
PubMed1983

Delayed effects of noise on the ear.

The possibility that a delayed onset hearing loss may occur after noise exposure was investigated in 20 normotensive (N) and 20 spontaneously hypertensive (SH) Wistar rats. Half of the rats of each strain were first exposed to noise at 3 months of age and half were first exposed at 12 months of age. All rats were exposed for a total of 3 months to a noise of 100 dB Leq (lin) (a narrowband noise, sweeping from 3 to 30 kHz at a rate of 0.5 Hz). Hearing thresholds were determined with a behavioral technique, and also on certain selected animals by brainstem audiometry, using pulses of 1/3-octave filtered sine waves. One to two weeks after exposure to noise animals had a 30-50 dB hearing loss. The hearing loss remained stable or progressed only slightly in normotensive animals up to 12 months after end of exposure. Generally the SH animals suffered a slight additional loss of hearing over the 12 months after noise exposure. When tested at 18 months of age 3 of the 10 SH rats exposed to noise from 12 to 15 months of age suffered a hearing loss which covered the whole range of observed frequencies from 1.5 to 44 kHz and which had progressed noticeably. These results suggest that while the delayed effects of noise are normally small, exposure might trigger a pronounced hearing loss in subjects with fragile ears.

Age Factors↗
PubMed1983

Responses from AVCN units in the cat before and after inducement of an acute noise trauma.

Acoustically evoked responses of single units in the anteroventral part of the cochlear nucleus (AVCN) in the cat were studied together with compound eighth-nerve action potentials (AP). Halfway through the experiments the cats were exposed for half an hour to pink noise at 105 dB SPL, producing an average threshold shift of 30 dB (maximum 50 dB) in the 2-6 kHz region. The effect of noise exposure was studied in two ways. On the one hand we compared the results for one population of units measured before the noise exposure with those found for another population measured afterwards. On the other hand we compared the results before and after the noise exposure for one unit that could be kept under observation during the noise exposure. After the noise exposure spontaneous activity and phase-locking of the responses of the units to the stimulus waveform were not significantly different from the pre-exposure findings. Response latency tended to increase. Therefore, the decrease of latency found for APs must be due to a shift to higher frequencies of the population of units contributing to the AP. The sharply tuned tip segments of tuning curves shift to higher levels whereas the low-frequency tails remain at about the same level. Q10 decreases by at most 50%, which was also found for AP tuning curves. Response spectra for clicks and noise (reverse correlation function) did not show a significant decrease of frequency selectivity. Units with CF less than 3 kHz may show a shift of CF to a lower frequency by 10-20%. After inducement of the noise trauma the sharply tuned tip segment of a tuning curve may not be found and CF may be assigned to a local minimum in the low-frequency tail of the tuning curve.

Animals↗
PubMed1989

Induced suppression in spike responses to tone-on-noise stimuli in the auditory nerve of the pigeon.

Spike potentials were recorded from single, afferent fibres in the pigeon auditory nerve. Pure-tone stimuli were presented in quiet and in combination with wide band noise. Presented alone, tones produced tuned response areas; noise generally drove spike rate to well above the spontaneous rate measured in quiet. When presented in combination with noise, tones up to 75 dB SPL at frequencies far from the fibre's response area had no effect on the noise-driven spike rate. As the tone frequency was shifted towards the response area, from above or below CF, suppression of the noise-driven spike rate became stronger until the tone reached the edge of the response area. Suppression of the noise-driven rate was directly proportional to the level of the tone. Within the area of response to the tone, tone-driven spike rates generally were unchanged or variably decreased (occasionally slightly increased) by tone-on-noise stimulation, depending on the relation of the tone frequency to CF and the level of the tone relative to that of the noise. Tuning properties were unaffected. It is suggested that in the pigeon, the suppression of driven spike rate during presentation of combination stimuli, which is common to all fibres, depends on the same mechanism as the suppression of spontaneous firing by tones that is observed in a proportion of fibres (Temchin, A.N. (1988), J. Comp. Physiol. A 163, 99-115; Hill et al., (1989) Hear. Res. 39, 37-48).

Acoustic Stimulation↗
PubMed2005

Noise in the ED.

BACKGROUND: The impact of noise pollution on both the patient and the care provider has been extensively studied in the neonatal intensive care unit and in other critical care units. Noise pollution makes errors more probable and is one of the risk factors for provider burnout and negative outcomes for patients. The Environmental Protection Agency (EPA) recommends that the acceptable noise level in a hospital should not exceed 40 dB. OBJECTIVES: The purpose of this study was to record and analyze noise in a large urban level I emergency department (ED) and compare to the EPA guidelines. METHODS: A 3-channel dosimeter Quest Q300 (Quest Technologies, Oconomowoc, WI) was placed as a stand-alone unit on the wall of the resuscitation booth in the ED. Sound was sampled 16 times per second for 12 hours and was recorded as peaks and averages for each minute. The dosimeter was then placed in the pocket of a medical student with a small 8-mm shoulder-mount type 2 microphone. The medical student followed an emergency medicine resident throughout an 8-hour shift in the main resuscitation area while monitoring and logging sound fluctuations in the environment. Sound pressure levels were logged in real time and subsequently correlated to the recorded peaks. Sound was sampled 16 times per second and recorded peaks and averages for each minute. RESULTS: In the initial part of the study, the time-weighted average was 43 dB. The average sound levels peaked approximately 25 times over 12 hours. Individually measured peak levels of 94 to 117 dB occurred every minute. In the second part of the study, the time-weighted average was 52.9 dB. CONCLUSIONS: When compared to EPA accepted noise levels for hospital (40 dB), the ED under study had excessive noise on a regular basis. There are easily identifiable sources of noise pollution in the ED. By identifying and modifying sources of noise, stress in the ED may be decreased.

Emergency Service, Hospital↗
PubMed2006

Do former preterm infants remember and respond to neonatal intensive care unit noise?

BACKGROUND: Previous studies have shown that 4-month-old infants have a decrease in heart rate, a component of the orienting reflex, in response to interesting auditory stimuli and an increase in heart rate to aversive auditory stimuli. OBJECTIVE: To compare the heart rate responses of former preterm and term infants at 4-5 months corrected age to a recording of NICU noises. METHODS: 13 former preterm infants and 17 full-term infants were presented NICU noise and another noise of similar level and frequency content in random order. Heart rate 10s prior to the stimulus and for 20s during the stimulus was analyzed. Group differences in second by second heart rate changes in response to the two noise stimuli were compared by analysis of covariance. RESULTS: Both the preterm and term newborns responded similarly to the NICU noise and the control noise. The preterm infants did not alter their heart rate in response to either stimulus. In contrast, the term infants displayed an orienting response to the second stimulus presented regardless of whether it was the NICU or control noise. CONCLUSIONS: Former preterm infants at 4-5 months corrected age have reduced responsiveness to auditory stimulation in comparison to 4- to 5-month-old term infants. Furthermore, they did not respond to the NICU noise as an aversive stimulus.

Acoustic Stimulation↗
PubMed2005

Arrest in ciliated cell expansion on the bronchial lining of adult rats caused by chronic exposure to industrial noise.

Workers chronically exposed to high-intensity/low-frequency noise at textile plants show increased frequency of respiratory infections. This phenomenon prompted the herein investigation on the cytology of the bronchial epithelium of Wistar rats submitted to textile noise. Workplace noise from a cotton-mill room of a textile factory was recorded and reproduced in a sound-insulated animal room. The Wistar rats were submitted to a weekly schedule of noise treatment that was similar to that of the textile workers (8h/day, 5 days/week). Scanning electron microscopy (SEM) was used to compare the fine morphology of the inner surface of the bronchi in noise-exposed and control rats. SEM quantitative cytology revealed that exposure to noise for 5-7 months caused inhibition in the natural expansion of the area occupied by ciliated cells on the bronchial epithelium as adult rats grow older. This difference between noise-exposed and age-matched control rats was statistically significant (P<0.05) and documents that the cytology of the rat bronchial epithelium is mildly altered by noise exposure. The decrease in the area of bronchial cilia may impair the mucociliar clearance of the respiratory airways and, thus, increase vulnerability to respiratory infection.

Animals↗
PubMed2005

Effects of acoustic noise on the auditory nerve compound action potentials evoked by electric pulse trains.

This study investigated the effects of acoustic noise on the auditory nerve compound action potentials in response to electric pulse trains. Subjects were adult guinea pigs, implanted with a minimally invasive electrode to preserve acoustic sensitivity. Electrically evoked compound action potentials (ECAP) were recorded from the auditory nerve trunk in response to electric pulse trains both during and after the presentation of acoustic white noise. Simultaneously presented acoustic noise produced a decrease in ECAP amplitude. The effect of the acoustic masker on the electric probe was greatest at the onset of the acoustic stimulus and it was followed by a partial recovery of the ECAP amplitude. Following cessation of the acoustic noise, ECAP amplitude recovered over a period of approximately 100-200 ms. The effects of the acoustic noise were more prominent at lower electric pulse rates (interpulse intervals of 3 ms and higher). At higher pulse rates, the ECAP adaptation to the electric pulse train alone was larger and the acoustic noise, when presented, produced little additional effect. The observed effects of noise on ECAP were the greatest at high electric stimulus levels and, for a particular electric stimulus level, at high acoustic noise levels.

Action Potentials↗
PubMed2005

Prevention of noise-induced hearing loss with Src-PTK inhibitors.

Studies from our lab show that noise exposure initiates cell death by multiple pathways [Nicotera, T.M., Hu, B.H., Henderson, D., 2003. The caspase pathway in noise-induced apoptosis of the chinchilla cochlea. J. Assoc. Res. Otolaryngol. 4, 466-477] therefore, protection against noise may be most effective with a multifaceted approach. The Src protein tyrosine kinase (PTK) signaling cascade may be involved in both metabolic and mechanically induced initiation of apoptosis in sensory cells of the cochlea. The current study compares three Src-PTK inhibitors, KX1-004, KX1-005 and KX1-174 as potential protective drugs for NIHL. Chinchillas were used as subjects. A 30 microl drop of one of the Src inhibitors was placed on the round window membrane of the anesthetized chinchilla; the vehicle (DMSO and buffered saline) alone was placed on the other ear. After the drug application, the middle ear was sutured and the subjects were exposed to noise. Hearing was measured before and several times after the noise exposure and treatment using evoked responses. At 20 days post-exposure, the animals were anesthetized their cochleae extracted and cochleograms were constructed. All three Src inhibitors provided protection from a 4 h, 4 kHz octave band noise at 106 dB. The most effective drug, KX1-004 was further evaluated by repeating the exposure with different doses, as well as, substituting an impulse noise exposure. For all conditions, the results suggest a role for Src-PTK activation in noise-induced hearing loss (NIHL), and that therapeutic intervention with a Src-PTK inhibitor may offer a novel approach in the treatment of NIHL.

Animals↗