The aim of the study was to evaluate the combined effect of noise exposure and additional risk factors on permanent hearing threshold shift. Three additional risk factors were: exposure to organic solvents, smoking and elevated blood pressure.

The data on exposure and health status of employees were collected in 24 factories. The study group comprised of 3741 noise male exposed workers of: mean age 39±8 years, mean tenure 16±7 years and LEX,8h = 86 ± 5 dB. For each subject, hearing level was measured with pure tone audiometry, blood pressure and noise exposure were assessed from the records of local occupational health care and obligatory noise measurements performed by employers. Smoking and solvent exposure were assessed with questionnaire. The study group was divided into subgroups with respect to the considered risk factors. In the analysis, the distribution of hearing level of each subgroup was compared to the predicted one which the standard calculation method described in ISO 1999:1990. For each of the considered risk factors, the difference between measured and calculated hearing level distribution was used to establish, by the least square method, a noise dose related correction square function for the standard method. The considered risk factors: solvent exposure, smoking and elevated blood pressure combined with noise exposure, may increase degree of hearing loss.

The aim of the study was to compare the extended high-frequency (EHF) hearing thresholds (10–16 kHz) in tinnitus and non-tinnitus ears, in a group of 98 patients with unilateral tinnitus and normal hearing at standard audiometric frequencies, in a 0.125–8 kHz range. It was found that a total of 65 patients (66%) had a hearing loss (a threshold shift >20 dB HL) in the EHF range and the EHF hearing loss occurred more frequently in the tinnitus ear than in the non-tinnitus ear. The data also indicate that the EHF thresholds increased with the patient’s age and were in most patients higher in the tinnitus ear than in the non-tinnitus ear.

The aim of this study was to evaluate the hearing status of call centre operators in relation to their noise exposure. Conventional pure-tone audiometry and extended high-frequency audiometry were performed in 49 workers, aged 22–47 years (mean ± SD: 32.0 ± 6.0 years), working in call centre from 1.0 to 16.5 years (mean ± SD: 4.7 ± 2.9 years).

Questionnaire inquiry aimed at collecting personal data, the information on ommunication headset usage habits, self-assessment of hearing ability and identification of risk factors for noise-induced hearing loss were also carried out. Sound pressure levels generated by the communication headset were determined using the artificial ear technique specified in CSA Z107.56-13 (2013) standard. The background noise prevailing in offices was also measured according to PN-N-01307 (1994) and PN-EN ISO 9612 (2011).

Personal daily noise exposure levels in call centre operators varied from 66 to 86 dB (10–90th percentile). About half of the study subjects had normal hearing in the standard frequencies (from 250 to 8000 Hz) in both ears, while only 27.1% in the extended high-frequencies (9–16 kHz). Moreover, both high-frequency and speech-frequency hearing losses were observed in less than 10% of audiograms, while the extended high-frequency threshold shift was noted in 37.1% of analysed ears. The hearing threshold

levels of call centre operators in the frequency of 0.25–11.2 kHz were higher (worse) than the expected median values for equivalent (due to age and gender) highly screened population specified in ISO 7029 (2017). Furthermore, they were also higher than predicted for 500–4000 Hz according to ISO 1999 (2013) based on the results of noise exposure evaluation.

The aim of the study was to examine the relationship between tinnitus pitch and maximum hearing loss, frequency range of hearing loss, and the edge frequency of the audiogram, as well as, to analyze tinnitus loudness at tinnitus frequency and normal hearing frequency.

The study included 212 patients, aged between 21 to 75 years (mean age of 54.4 ± 13.5 years) with chronic subjective tinnitus and sensorineural hearing loss. For the statistical data analysis we used Chisquare test and Fisher’s exact test with level of significance p < 0:05.

Tinnitus pitch corresponding to the frequency range of hearing loss, maximum hearing loss and the edge frequency was found in 70.8%, 37.3%, and 16.5% of the patients, respectively. The majority of patients had tinnitus pitch from 3000 to 8000 Hz corresponding to the range of hearing loss (p < 0:001). The mean tinnitus pitch was 3545 Hz ± 2482. The majority (66%) of patients had tinnitus loudness 4–7 dB SL. The mean sensation level at tinnitus frequency was 4.9 dB SL ± 1.9, and 13 dB SL ± 2.9 at normal hearing frequency.

Tinnitus pitch corresponded to the frequency range of hearing loss in majority of patients. There was no relationship between tinnitus pitch and the edge frequency of the audiogram. Loudness matching outside the tinnitus frequency showed higher sensation level than loudness matching at tinnitus frequency.

The aim of the study study was to model, with the use of a neural network algorithm, the significance of a variety of factors influencing the development of hearing loss among industry workers. The workers were categorized into three groups, according to the A-weighted equivalent sound pressure level of noise exposure: Group 1 (LAeq < 70 dB), Group 2 (LAeq 70–80 dB), and Group 3 (LAeq > 85 dB). The results obtained for Group 1 indicate that the hearing thresholds at the frequencies of 8 kHz and 1 kHz had the maximum effect on the development of hearing loss. In Group 2, the factors with maximum weight were the hearing threshold at 4 kHz and the worker’s age. In Group 3, maximum weight was found for the factors of hearing threshold at a frequency of 4 kHz and duration of work experience. The article also reports the results of hearing loss modeling on combined data from the three groups. The study shows that neural data mining classification algorithms can be an effective tool for the identification of hearing hazards and greatly help in designing and conducting hearing conservation programs in the industry.

If we want to provide the efficient training intervention to increase the duration of using hearing protection devices (HPDs) by workers, we need a tool that can estimate the person’s hearing threshold taking into account noise exposure level, age, and work history, and compare them with audiometry to find out the percent reduction of workers hearing loss.

First, the workers noise exposure level was determined according to ISO 9612, then 4000 Hz audiometry was done to find age and work history. On basis of ISO 1999 the hearing threshold was estimated and if the hearing protection device was not used continuously and correctly, the hearing protection device’s actual performance was reduced adjusted with person’s audiometry. After training intervention, the estimate was done again and was compared with the adjusted audiometry.

According to ISO 1999 standard estimation results, the percent reduction of the workers hearing loss level was 6.48 dB in intervention group. This level remained unchanged in control group. The mean score of hearing threshold estimation (standard ISO 1999) was statistically more significant than mean score of hearing threshold (p-value ¡ 0.001). The results show not significant change in control group due to lack of changing of noise exposure level.

In regards to the results of hearing threshold estimation based on ISO 1999 and comparing with workers audiometry, it can be seen that BASNEF training intervention increases the duration of using the HPDs and it could be effective in reducing hearing threshold related to noise.

Background: Hearing loss caused by excessive exposure to noise is one of the most common health risks for employees. One solution for noise reduction is the use of hearing protectors, which is a very effective method for protecting hearing from the workplace noise. In order to obtain better attenuation efficiency, custom moulded earplugs can be equipped with a suitable acoustic filter. The effectiveness of the hearing protectors’ attenuation is based on real measurement of hearing thresholds for normal hearing people with and without hearing protectors. However, this is a time consuming process, and the obtained values are characterised by quite large inter-individual variability. The optimal solution is to measure the attenuation characteristics based on the objective method (without the presence of the subject), the results of which will be in accordance with the results of subjective tests. Therefore, the main purpose of the research in this work was to measure the attenuation characteristics of the self-designed custom moulded earplugs with and without acoustic filters through the use of subjective and objective methods, and to compare the results in terms of the research methods.

Methods: Measurements of the acoustic attenuation obtained by custom moulded earplugs with designed F1, F2, and F3 acoustic filters (internal diameters dF1 = 1:25 mm, dF2 = 0:85 mm, and dF3 = 0:45 mm), as well as full insert earplugs (without any acoustic filters) were carried out using two methods: objective and subjective. The objective measurements were carried out in an anechoic chamber. The artificial head (High-frequency Head and Torso Simulator Brüel & Kjær Type 5128) was located at a distance of 3 m, directly opposite the loudspeaker. The test signal in the measurements was pink noise – in the frequency range up to 12.5 kHz and the level 85, 90, and 95 dB. The hearing protectors with and without acoustic filters were mounted in the Head and Torso Simulator which was connected with Pulse System Brüel & Kjær. Five normal hearing subjects participated in the subjective measurements. A pink noise signal was used for one-third octave bands: 125, 250, 500, 1000, 2000, 4000, and 8000 Hz. The attenuation value was defined as the difference (in dB) between the hearing threshold of the test signal with a hearing protector and the hearing threshold determined without a hearing protector.

Results: The results of the objective method proved that in addition to the significant impact of frequency on the attenuation values, the type of filter used in custom moulded earplugs also had a significant effect. In addition, the results of the objective method showed that in the whole frequency range the highest attenuation values are shown by the full earplugs, achieving slightly above 45 dB for frequency of 8 kHz. The attenuation values obtained from subjective measurements also confirmed that both the frequency and type of filter significantly affect the attenuation values of the tested hearing protectors.

Conclusions: The results of this study did not confirm the hypothesis that the measurement method had no significant effect on the attenuation characteristics of self-designed custom moulded earplugs with different types of acoustic filters. The largest differences in attenuation values between the type of measurement methods occur for the low frequency band (250 Hz) and for higher frequencies (4000 Hz mainly). The change of the internal diameter of the F1 filter from 1.25 mm to 0.85 mm (F2 filter) did not significantly affect the attenuation characteristics.

Noise induced hearing loss (NIHL) as one of the major avoidable occupational related health issues has been studied for decades. To assess NIHL, the excitation pattern (EP) has been considered as one of the mechanisms to estimate the movements of the basilar membrane (BM) in the cochlea. In this study, two auditory filters, dual resonance nonlinear (DRNL) filter and rounded-exponential (ROEX) filter are applied to create two EPs, the velocity EP and the loudness EP respectively. Two noise hazard metrics are proposed based on two proposed EPs to evaluate hazardous levels caused by different types of noise. Moreover Gaussian noise and tone signals are simulated to evaluate performances of the proposed EPs and the noise metrics. The results show that both EPs can reflect the responses of the BM to different types of noise. For Gaussian noise there is a frequency shift between the velocity EP and the loudness EP. The results suggest that both EPs can be used for assessment of NIHL.

The overall purpose of this study was to assess hearing status in professional orchestral musicians. Standard pure-tone audiometry (PTA) and transient-evoked otoacoustic emissions (TEOAEs) were per- formed in 126 orchestral musicians. Occupational and non-occupational risk factors for noise-induced hearing loss (NIHL) were identified in questionnaire inquiry. Data on sound pressure levels produced by various groups of instruments were also collected and analyzed. Measured hearing threshold levels (HTLs) were compared with the theoretical predictions calculated according to ISO 1999 (1990). Musicians were exposed to excessive sound at weekly noise exposure levels of for 81-100 dB (mean: 86.6±4.0 dB) for 5-48 years (mean: 24.0±10.7 years). Most of them (95%) had hearing corresponds to grade 0 of hearing impairment (mean hearing threshold level at 500, 1000, 2000 and 4000 Hz lower than 25 dB). However, high frequency notched audiograms typical for noise-induced hearing loss were found in 35% of cases. Simultaneously, about 35% of audiograms showed typical for NIHL high frequency notches (mainly occurring at 6000 Hz). When analyzing the impact of age, gender and noise exposure on hearing test results both PTA and TEOAE consistently showed better hearing in females vs. males, younger vs. older musicians. But higher exposure to orchestral noise was not associated with poorer hearing tests results. The musician’s audiometric hearing threshold levels were poorer than equivalent non-noise-exposed population and better (at 3000 and 4000 Hz) than expected for noise-exposed population according to ISO 1999 (1990). Thus, music impairs hearing of orchestral musicians, but less than expected from noise exposure.

Objective: Self-report questionnaire is informative to assess general hearing disability. The aims of this study were to investigate the reliability of Turkish version of spatial hearing questionnaire (SHQ) and to analyze the validity of the SHQ by the correlation with speech, spatial, and qualities of hearing questionnaire (SSQ) and Turkish matrix sentence test (TMST).
Methods: The first part of the study was the psychometric properties of the SHQ with 192 participants (137 with normal hearing, 55 with hearing loss). In the second and main part of the study, we applied two questionnaires (SHQ and SSQ) and TMST to people other than those included in the first part ofthe study (88 participants with bilateral sensorineural hearing loss). We compared the results of these two questionnaires and the TMST with the speech discrimination (SD) scores.
Results: Turkish spatial hearing questionnaire’s internal consistency was 0.94 and 0.97 for individuals with normal hearing and for individuals with hearing loss, respectively. Moderate, positive, statistically significant correlation was observed between the SHQ and SSQ (r = 0:606, p = 0:001 in individuals with hearing loss who do not wear any hearing aid, and r = 0:627, p = 0:001 in hearing aid users), and SHQ and SD (r = 0:561, p = 0:032 in hearing aid users). According to TMST, moderate, positive, statistically significant correlation was found between SSQ and adaptive TMST in individuals with hearing loss who do not wear any hearing aid (r = 0:330, p = 0:033 for S0N90 and r = 0:364, p = 0:018 for S0N270).
Conclusions: Turkish SHQ is a valid and reliable questionnaire for assessing hearing functions. SHQ, SSQ, and TMST are clinically beneficial measuring tools in planning the process of hearing rehabilitation and follow-up.

The aim of this work is to present problems related to tinnitus symptoms, its pathogenesis, hypotheses on tinnitus causes, and therapy treatment to reduce or mask the phantom noise. In addition, the hypothesis on the existence of parasitic quantization that accompanies hearing loss has been recalled. Moreover, the paper describes a study carried out by the Authors with the application of high-frequency dither having specially formed spectral characteristics. Discussion on preliminary results obtained and conclusions are also contained.

The study presents evaluating the effectiveness of the hearing aid fitting process in the short-term use (7 days). The evaluation method consists of a survey based on the APHAB (Abbreviated Profile of Hearing Aid Benefit) questionnaire. Additional criteria such as a degree of hearing loss, number of hours and days of hearing aid use as well as the user’s experience were also taken into consideration. The outcomes of the benefit obtained from the hearing aid use in various listening environments for 109 hearing aid users are presented, including a degree of their hearing loss. The research study results show that it is possible to obtain relevant and reliable information helpful in assessing the effectiveness of the shortterm (7 days) hearing aid use. The overall percentage of subjects gaining a benefit when communicating in noise is the highest of all the analyzed and the lowest in the environment with reverberation. The statistical analysis performed confirms that in the listening environments in which conversation is held, a subjective indicator determined by averaging benefits for listening situations individually is statistically significant with respect to the degree of hearing loss. Statistically significant differences depending on the degree of hearing loss are also found separately for noisy as well as reverberant environments. However, it should be remembered that this study is limited to three types of hearing loss, i.e. mild, moderate and severe. The acceptance of unpleasant sounds gets the lowest rating. It has also been observed that in the initial period of hearing aid use, the perception of unpleasant sounds has a big influence on the evaluation of hearing improvement.

Noise induced hearing loss (NIHL) is a serious occupational related health problem worldwide. The A-wave impulse noise could cause severe hearing loss, and characteristics of such kind of impulse noise in the joint time-frequency (T-F) domain are critical for evaluation of auditory hazard level. This study focuses on the analysis of A-wave impulse noise in the T-F domain using continual wavelet transforms. Three different wavelets, referring to Morlet, Mexican hat, and Meyer wavelets, were investigated and compared based on theoretical analysis and applications to experimental generated A-wave impulse noise signals. The underlying theory of continuous wavelet transform was given and the temporal and spectral resolutions were theoretically analyzed. The main results showed that the Mexican hat wavelet demonstrated significant advantages over the Morlet and Meyer wavelets for the characterization and analysis of the A-wave impulse noise. The results of this study provide useful information for applying wavelet transform on signal processing of the A-wave impulse noise.