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Objectives. The present study aimed to investigate the effect of tonal noise and task difficulty on electroencephalography (EEG) and cognitive performance. Methods. Twelve healthy volunteers participated in the present study. Four noise signals were generated by four prominence tone levels (0, 2, 5 and 9) at background noise levels of 55 dBA and frequency of 500 Hz using the Test Tone Generator from Esser Audio (USA). The participants were asked to perform the tasks with low, moderate and high levels of difficulty while exposed to the noises in an acoustics laboratory. The values of reaction time, correct rate and missed numbers were recorded during each step. Moreover, the EEG signals were measured. Results. The results showed that higher tone level and more task difficulty significantly decreased the correct rate, and increased the miss numbers. However, no significant effect was observed on reaction times. Furthermore, tone level and task difficulty significantly increased activity of the θ and β bands and decreased activity of the α band. Conclusion. Task difficulty and tone level could significantly affect the parameters of performance and the activity of EEG bands. Therefore, noise control can help sustain appropriate performance.

Concurrent exposure to styrene (ST) and noise is common especially in industrial environments. The present study aims to determine the related oxidant-induced changes as the result of combined exposure to ST and noise. For this purpose, 24 male Wistar rats were used in four experimental groups ( n =  6/groups): (1) control group, (2) the group exposed to an octave band of noise centered at 8 kHz (100 dB SPL) (6 h/day), (3) the group inhalationally exposed to ST (750 ppm) (6 h/day), (4) the group exposed to noise and ST simultaneously. The DNA damage was measured by assessing the concentration of 8-hydroxyl-2-deoxyguanosine (8-OHdG) using ELISA kit. Levels of lipid peroxidation (MDA), GSH and antioxidative activity of SOD and CAT were also determined in whole lung tissues. The results relatively indicated that sub-acute exposure to both noise and ST can lead to pathological damage in rat lung tissues. Furthermore, enhanced levels of 8-OHdG and MDA production were observed in lung tissues. In contrast, GSH, CAT and SOD were markedly reduced in co-exposed group. The results of the study verified additive interaction between noise and ST on accumulation of DNA oxidation products, progressive morphological damages as well as undermining the antioxidative defense system in the rat lung tissues.

Recent evidences showed that, noise stress causes abnormal changes in structure and function of central nervous system (CNS). The Current study was conducted to evaluate some stereological parameters of the medial prefrontal cortex (mPFC) of male pups of Wistar rat after prenatal and early postnatal noise stress. 18 pregnant Wistar rats were randomly divided into prenatal noise-exposed (NE) group, postnatal NE group, and controls. Male pups of NE groups were exposed to noise 100 dB at the frequency ranges of 500-8000 Hz, 4 h per day from gestational day one (GD1) to GD21 for the prenatal NE group, and from postnatal day one (PND1) to PND21 in the postnatal NE group. The Control group animals were maintained under standard condition without noise stimulation. Corticosterone level in plasma was measured using ELISA technique. Changes of the neurons and non-neurons cells number and volume of the mPFC were evaluated by stereological analysis. Tunnel assay was also used for detection of apoptotic cells. Increase in plasma corticosterone level, decrease in the number of neurons, and increase in the apoptotic cells number were observed in both NE groups. Decrease in volume of mPFC and also in non-neurons cells number was observed in the prenatal NE group. An increase in the non-neurons number was seen in the postnatal NE group. Data of the current comparative study showed that, noise stress during prenatal and early postnatal periods can induce the abnormal alteration in some stereological parameters of mPFC in male pups of Wistar rat. These negative alterations were more remarkable after prenatal noise stress., Competing Interests: Declaration of Competing Interest The authors declare no conflict of interest., (Copyright © 2020 Elsevier GmbH. All rights reserved.)

Cigarette smoking is a possible risk factor for hearing loss. However, the impact of simultaneous exposure to noise and smoke on hearing has remained controversial. This study investigated the combined effect of exposure to cigarette smoking and noise on hearing loss. Three groups of male Wistar rats (275 ± 25 g) were subjected to white noise (102 ± 0.5 dB), cigarette smoking (20 cigarettes), and both cigarette smoking and noise for 8 h and 10 days inside the exposure chamber. The control group was exposed to neither noise nor smoke. Distortion product otoacoustic emissions (DPOAE) were measured before any intervention, and it was repeated 1, 7, and 21 days after the last exposure. One-day postexposure to noise, cigarette smoking, and both cigarette smoking and noise, the mean of DPOAE amplitudes decreased significantly ( p < 0.05) between, respectively, 5.7-30.7, 1.5-7.5, and 5.2-32.6 dB within the frequency range of 4620-9960. Temporal DPOAE change in rats exposed to noise or both cigarette smoking and noise was not significantly different ( p > 0.05). DPOAE amplitudes returned to the baseline values in the group subjected to smoking 21 days postexposure. The most permanent change was observed in rats exposed to both cigarette smoking and noise. Accordingly, simultaneous subacute exposure to noise and cigarette smoking increases the effect of noise on permanent hearing loss. Therefore, smoking workers exposed to noise might be at a greater risk of developing hearing loss, and it is recommended that authorities in charge take note of this evidence.

Objectives: To investigate the interaction between welding fumes and noise in causation of hearing impairment., Methods: Groups of rabbits (n=6) were exposed to noise, welding fumes or combination of both prior to Distortion Product Otoacoustic-Emissions (DPOAEs) analysis. The function of outer hair cells (OHCs) was examined by DPOAE assessment over a broad range of frequencies. Variations in DPOAE amplitude were compared between control (n=6) and exposed (n=18) groups., Results: The DPOAEs levels measured at different frequencies (1379-6299 Hz) were found to decrease significantly (P<0.05) in rabbits exposed to 110 dB sound pressure level (SPL) broadband noise (8h/day, 12 days). In rabbits, exposed to carbon-steel welding fumes alone (157 mg/m(3)), the threshold shift was limited to the high frequencies (2759-6299 Hz), whereas, mixed exposure to noise and fumes resulted in reduction of DPOAEs at all the frequencies. Changes in DPOAEs were associated with increased susceptibility of erythrocytes to oxidation (P<0.05). Exposure to noise or fumes alone or simultaneously, suppressed total antioxidant ability of plasma as measured by ferric reducing ability of plasma (FRAP). Noise alone or in combination with fumes resulted in depletion of blood glutathione (GSH). Despite suppression of FRAP in the exposed groups, GSH was found to remain unchanged due to welding fumes suggesting that antioxidants other than GSH are affected by toxicants present in metal welding fumes., Conclusion: Exposure to very high levels of welding fumes can increase noise-related effects on OHC function by extending hearing threshold shift to wide band frequencies.

Co-exposure to noise and nanomaterials, such as silver nanoparticles (Silver-NPs), is a common occurrence in today's industries. This study aimed to investigate the effects of exposure to noise and the administration of silver-NPs on the liver tissue of rats. Thirty-six adult male albino Wistar rats were randomly divided into six groups: a control group (administered saline intraperitoneally), two groups administered different doses of Silver-NPs (50 mg/kg and 100 mg/kg, 5 days a week for 28 days), two groups exposed to noise in addition to Silver-NPs (at the same doses as mentioned before), and a group exposed only to noise (104 dB, 6 hours a day, 5 days a week for 4 weeks). Blood samples were taken to assess hepatic-functional alterations, such as serum ALP, ALT, and AST levels. Additionally, biochemical parameters (MDA, GPX, and CAT) and the silver concentration in the liver were measured. Histopathological analysis, mRNA expression (P53 and NF-κB), protein expression (CYP450), and liver weight changes in rats were also documented. The study found that the administration of Silver-NPs and exposure to noise resulted in elevated levels of ALP, ALT, AST, and MDA (p <.01). Conversely, GPX and CAT levels decreased in all groups compared with the control group (p <.0001). There was a significant increase (p <.05) in liver weight and silver concentration in the liver tissues of groups administered Silver-NPs (50 mg/kg) plus noise exposure, Silver-NPs (100 mg/kg), and Silver-NPs (100 mg/kg) plus noise exposure, respectively. The expression rate of P53, NF-κB, and cytochromes P450 (CYPs-450) was increased in the experimental groups (p <.05). These findings were further confirmed by histopathological changes. In conclusion, this study demonstrated that exposure to noise and the administration of Silver-NPs exacerbated liver damage by increasing protein and gene expression, causing hepatic necrosis, altering biochemical parameters, and affecting liver weight. [ABSTRACT FROM AUTHOR]

[Display omitted] • SNPs, noise, independently and combined, decreased hearing performance. • TUBB3, MYH-7 expression decrease in rat cochlea after exposure to SNPs and noise. • The treatments changed IL-6, TNF-α, NOX3 expression in rat cochlea. • Quercetin improves hearing, reduces oxidative stress in noise-exposed and SNPs. • Que improves independent exposures more than combined exposures the treatments. The aim of this study was to investigate the otoprotective effects of Quercetin (Que) against both noise-induced hearing loss (NIHL) and the ototoxicity of silver nanoparticles (SNPs) in rats. Forty-two male Wistar rats were divided into seven groups (n = 6): control, SNPs, Que (100 mg/kg) plus SNPs (100 mg/kg), noise (104 dB), Que plus noise, noise plus SNPs, and noise plus Que plus SNPs. In the weight change results, there was no significant difference between the groups exposed to noise plus SNPs and SNPs compared to the control group. However, animals had significant changes in DPOAE amplitude at 1 and 3 days post-exposure when compared to baseline. Additionally, the DPOAE value of rats administered with Que plus SNPs was higher than in all other groups. Que also decreased the levels of TACT, MDA, IL-6, TNF-α, and NOX3 in the groups exposed to noise and SNPs and increased the SOD level and expression of myosin heavy chain VII (MYH7) and β-tubulin III (TUBB3) proteins. Furthermore, Que decreased structural changes in the animals' cochlea. Our findings indicate that pretreatment with Que efficiently counteracted the adverse effects of noise and SNPs on inner hair cell, outer hair cell, and nerve cells, which are responsible for high-frequency perception. [ABSTRACT FROM AUTHOR]

Bachground: Noise is one of the most important harmful factors in the environment. There are limited studies on the effect of noise loudness on brain signals and attention. The main objective of this study was to investigate the relationship between exposure to different loudness levels with brain index, types of attention, and subjective evaluation. Methods: Four noises with different loudness levels were generated. Sixty-four male students participated in this study. Each subject performed the integrated visual and auditory continuous performance test (IVA-2) test before and during exposure to noise loudness signals while their electroencephalography was recorded. Finally, the alpha-to-gamma ratio (AGR), five types of attention, and the subjective evaluation results were examined. Results: During exposure to loudness levels, the AGR and types of attention decreased while the NASA-Tax Load Index (NASA-TLX) scores increased. The noise exposure at lower loudness levels (65 and 75 phon) leads to greater attention dysfunction than at higher loudness. The AGR was significantly changed during exposure to 65 and 75 phon and audio stimuli. This significant change was observed in exposure at all loudness levels except 85 phon and visual stimuli. The divided and sustained attention changed significantly during exposure to all loudness levels and visual stimuli. The AGR had a significant inverse correlation with the total score of NASA-TLX during noise exposure. Conclusions: These results can lead to the design of methods to control the psychological effects of noise at specific frequencies (250 and 4000 Hz) and can prevent non-auditory damage to human cognitive performance in industrial and urban environments. [ABSTRACT FROM AUTHOR]

Hearing loss induced by noise and combinations of factors is a common occupational disease among workers. This study aimed to investigate the impact of acute exposure to white noise and Al2O3 NPs, alone and in combination, on changes in the hearing and structural functions of the cochlea in rats. Thirty-six rats were randomly assigned to one of six groups: Control, acute exposure to white noise, exposure to γ-Al2O3 NPs, exposure to noise plus γ-Al2O3 NPs, exposure to α-Al2O3 NPs, and exposure to the combination of noise plus α-Al2O3 NPs. TTS and PTS were examined using DPOAE, while oxidative index (MDA, GSH-Px), gene expression (NOX3, TGF-ß, CYP1A1), protein expression (ß-Tubulin, Myosin VII), and histopathological changes were examined in the cochlea. The morphology of Al2O3 NPs was examined by TEM. The results of the DPOAE test showed a significant increase in TTS in all groups and an increase in PTS in the groups exposed to noise, γ-Al2O3 NPs, and a combination of noise plus Al2O3 NPs (P < 0.05). In the group exposed to white noise plus Al2O3 NPs, the MDA levels increased, the level of GSH-Px decreased, and the expression percentage of ß-Tubulin and Myosin VII decreased, while the expression of NOX3, TGF-ß, and CYP1A1 (except for the α-Al2O3 NPs group) significantly increased (P < 0.05). Histopathological changes of the cochlea indicated damage to hair and ganglion cells, which was more severe in the combined exposure group. The combined and independent exposure to white noise and Al2O3 NPs damaged hair and ganglion cells for high-frequency perception, affecting the function and structure of the cochlea and leading to TTS and PTS. [ABSTRACT FROM AUTHOR]

Background: There are considerable opium addicts, particularly among workers in Iran's industrial sectors. This study aimed to investigate the effects of simultaneous exposure to excessive noise and opium addiction on adult rat sperm parameters. Materials and Methods: In this experimental study 42 adult Wistar male rats in 6 groups were studied as follows: group 1 control, group 2 exposed to noise (100 dB) 8 h/day, group 3 received daily 50 mg/case opium solution, group 4 received daily 100 mg/case opium solution, group 5 received daily 50 mg/case opium solution and exposed to noise 8h/day, and group 6 received daily 100 mg/case opium solution and exposed to noise 8h/day. After 50 days, cauda epididymis was removed for sperm parameters examination (WHO guidelines). Results: In the groups receiving opium (50 and 100 mg/case), sperm count, sperm viability, and normal sperm morphology (%) significantly decreased compared to the control group. Exposure to noise and consumption of opium solution simultaneously significantly reduced the count, viability, and percentage of sperm with normal morphology in both selected doses, as well as a significant difference between groups 5 and 6 in count, viability, and normal sperm morphology(%) parameters(P<0.05). Conclusions: According to the results, noise exposure and taking opium would actively reduce the count, viability, and normal sperm morphology. It is therefore suggested that the mechanism of such effects should be investigated in animal and human studies. [ABSTRACT FROM AUTHOR]

Due to the high prevalence of noise and vibration exposure in most industries, this study aimed to investigate the effects of simultaneous exposure to noise and vibration on sex hormone levels and fertility capacity in rats, as well as the protective effects of the hydroalcoholic extract of cinnamon. In this experimental study, 64 adult male rats were randomly divided into 8 groups, control, noise (N), cinnamon (C), noise + cinnamon (NC), vibration (V), vibration + cinnamon (VC), noise + vibration (NV) and groups Noise + Vibration + Cinnamon (NVC). Groups C, NC, VC and NVC received a 75 mg/kg dose of cinnamon extract by gavage. The rats of groups N and NC, V and VC and NV and NVC were each exposed to noise at 100 dB (700–5700 Hz), vibration acceleration of 1 m/s2 rms (frequency range of 4–8 Hz), and simultaneously exposed to vibration and noise for 8 hours continuously every night (23:00–7:00) for 50 consecutive nights. Next, a blood sample was taken from the lateral tail vein and the levels of LH, FSH and testosterone were measured with ELISA kits. Each male rat was caged with 3 female rats for one week. The pregnant rats were kept until all of the rat pups were born. Then the fertility capacity, the total number of births, the live births and the birth weight of the rat pups were analyzed with the software SPSS. In the N and NV groups, compared to the control group, a significant decrease in LH and testosterone levels, the number of births and the birth weight was observed (p < 0.05). A significant decrease in testosterone levels, number of births and birth weight was observed in Group V compared to the control group (p < 0.05). In addition, significant increases in LH, FSH and testosterone levels and in birth weight were observed in group C compared to the control group (p < 0.05). Significant increases in FSH and testosterone levels, birth weight, and the number of births were noted in the NVC group compared to the NV group (p < 0.05). Based on the results of this study, cinnamon extract could alleviate the destructive effects of noise and vibration (both individually and in combination) on levels of sex hormones (LH, FSH, and testosterone), the number of births, and birth weight. [ABSTRACT FROM AUTHOR]

Rotating components in mechanical systems produce tonal noises and the presence of these tones effect the quality and comfort of occupants leading to annoyance and a decrease in mental performance. The ISO 1996-2 and ANSI S1.13 standards have described metrics to quantify the effects of prominent tones, but more research on how noise attributes effect annoyance and performance, especially in different levels of task difficulty are necessary. This paper investigates relations between noise metrics, annoyance responses and mental performance under different task difficulty levels while exposed to background noise with tonal components. In this study, sixty participants were evaluated on subjective perceived annoyance and varying workloads while exposed to 18 noise signals with three different prominence tones at three frequency tones and two background noise levels while doing three different levels of n-back tasks in a controlled test chamber. Performance parameters were measured by recording the reaction time, the correct rate, and the number of misses. The results indicate an increasing trend for number of misses and reaction times at higher task difficulty levels, but a decrease for correct rate. The study results showed a significant difference for subjective responses except for annoyance and loudness under different levels of task difficulty. The participants were more annoyed with higher background noise levels, lower tone frequencies and increasing tone levels especially under increasing task difficulty. Loudness metrics highly correlate with other noise metrics. Three models for the prediction of perceived annoyance are presented based on the most strongly correlated noise metrics using neural network models. Each of the three models had different input parameters and different network structures. The accuracy and MSE of all three neural network models show it to be appropriate for predicting perceived annoyance. The results show the effect of tonal noise on annoyance and mental performance especially in different levels of task difficulty. The results also suggest that neural network models have high accuracy and efficiency, and can be used to predict noise annoyance. Model 1 is preferred in certain aspects, such as lower input parameters, making it more user-friendly. The best neural network model included both loudness metrics and tonality metrics. It seems that combined metrics have the least importance and are unnecessary in the proposed neural network model. [ABSTRACT FROM AUTHOR]

Noise is considered as one of the harmful factors at industrial environments. It affects human health in different aspects including harmful influences on auditory, vision, neurological and psychiatric systems, hormones, physiological and mental systems. Paying attention to the importance of hormonal effects on human body seems to possess crucial importance. The aim of the present study is to investigate the effects of noise exposure on variation of serum levels of glucose and cortisol at Syrian adult male mouse. 36 Syrian male adult mice were randomly categorized into two experiment and control groups. Garlic powder was added to the mice pelleted food meal (equal to 1% of their daily diet) to study its effect on the cortisol and glucose serum levels. The mice pelleted food contains starch, glucose, isolated soya protein, etc., which are the rich resources of A, C, B1, B2 and B6 vitamins. Streptozotocin (60mg/kg) was injected to the mice at experiment group which were under noise exposure with intensity of 90dB in frequency range of 700-5700Hz. Noise were generated using CoolEdit software and distributed to the fabricated box for 30 days (8h/d). Fasting cortisol and glucose serum levels were measured for mice of both groups 24h after finishing the exposure period. Results indicated that the glucose serum level in non-diabetic and diabetic subjects under noise exposure had significant difference (p<0.002) with the subjects at control group. Also, cortisol level in non-diabetic and diabetic subjects under noise exposure indicated significant difference (p<0.002) with the subjects at control group. Exposure to noise with intensity of 90dB at frequency range of 700-5700Hz increases the glucose and cortisol serum levels. [ABSTRACT FROM AUTHOR]

Simultaneous exposure of highly-used chemical and physical agents are expected to happen in many occupations. In the present study the impact of simultaneous exposure to noise and formaldehyde on oxidative stress in blood and liver tissue of rat was investigated. Animal study was conducted in the School of Public Health, Shahid Beheshti University of Medical Scineces, Tehran, Iran in 2013. A total of 42 male Wistar albino rats were randomly divided into 6 groups (7 in each group). Rats in control group were not exposed to any stressor, while 2 groups were exposed to 6 and 12 ppm formaldehyde, 1 group to noise (0.7-5.7 kHz, 100 dB SPL) and 2 groups to noise + formaldehyde (8 h/d, 28 days). The level of oxidative stress in blood and liver tissue were determined through GSH and MDA measurements. Sound pressure level was monitored using a calibrated Bruel and Kjaer 2238 sound level meter (Denmark). Formaldehyde concentration was monitored four times an hour by a photo ionization detector (Photocheck +5000, Ionscience Co., UK). GSH concentrations were measured through titration and quantification of thio-nitro-benzene using spectrophotometry at 412 nm. MDA levels were quantified by absorption at 535 NM wavelengths using a spectrometer. The results revealed that exposure to both stressors significantly reduced the GHS levels and significantly increased the MDA levels in exposed rats. The level of changes in groups with simultaneous exposure was dose-dependent (p<0.05). The current study clearly confirmed that co-exposure to noise & formaldehyde has an additive effect in oxidant /antioxidant system imbalance. [ABSTRACT FROM AUTHOR]

Background and Aim: Noise-induced hearing loss is the most common problem in industrial areas. This study aimed to determine effects of excessive noise exposure on measurable characteristics of distortion product otoacoustic emissions (DPOAEs) in rabbits. Methods: The study was carried out on 12 adult male New Zealand White rabbits including case group--exposed to 500-8000 Hz broadband white noise with 100 dBA SPL for 8 hours per day in 5 consecutive days--and control group. After three days period of acclimatization to the experimental condition, rabbits' hearing status in each group were measured by distortion product otoacoustic emissions on days zero means before the study was initiated as a baseline, eight, one hour after the latest exposure to noise, and ten. The recorded results were analyzed using SPSS software. Results: Highest mean distortion product otoacoustic emissions amplitudes in case group were allocated to frequencies of 5888.50 Hz, 8166.50 Hz, 9855.00 Hz, 3956.00 Hz, and 3098.50 Hz, respectively. However, the lowest mean distortion product otoacoustic emissions amplitude was related to frequency of 588.00 Hz (p=0.001). Conclusion: This study revealed that distortion product otoacoustic emissions amplitude shifts due to noise occur first in high and then in middle frequencies. Additionally, exposure to noise can decrease distortion product otoacoustic emissions amplitudes. We conclude that distortion product otoacoustic emissions can be a reliable test for estimating personal susceptibility to noise-induced hearing loss. [ABSTRACT FROM AUTHOR]

The correct first names and last names are "Mohammad Javad Jafari", "Marzieh Sadeghian", "Ali Khavanin", "Soheila Khodakarim", "Amir Salar Jafarpisheh". [ABSTRACT FROM AUTHOR]

Background: Noise exposure causes loss of cochlea hair cells, leading to permanent sensorineural hearing loss, and initiates pathological changes to the bipolar primary auditory neurons (ANs). This study focuses on the effects of N-acetyl-l-cysteine (NAC) in protecting the density of spiral ganglion cells and in histological changes induced by continuous noise exposure in rats. Methods: Twenty-four male Wistar rats were randomly allocated into four experimental groups to receive NAC, saline, noise, or both noise and NAC. Noise exposure continued for ten days. Saline and NAC were injected daily during the noise exposure, and 2 days before and after the noise exposure. Evaluation of cochlear histopathology and the density of spiral ganglion cells was performed 21 days after exposure. Results: In the animals exposed to noise, a reduction in the density of spiral ganglion cells was evident in both the basal and middle turns of the cochlea. This improved on receiving NAC treatment (P = 0.046). In the histopathology evaluation, some histological changes, such as disorganised architecture of the outer hair and supporting cells and a slightly thickened basilar membrane, were found in the basal turns in the noise group. Conclusion: NAC offered partial protection against noise exposure by improving the density of spiral ganglion cells and reducing morphological changes. [ABSTRACT FROM AUTHOR]