Agreement between hearing thresholds measured in non-soundproof work environments and a soundproof booth

In-situ Audiometry Compared to Conventional Audiometry for Hearing Aid Fitting

The use of in-situ audiometry for hearing aid fitting is appealing due to its reduced resource and equipment requirements compared to standard approaches employing conventional audiometry alongside real-ear measures. However, its validity has been a subject of debate, as previous studies noted differences between hearing thresholds measured using conventional and in-situ audiometry. The differences were particularly notable for open-fit hearing aids, attributed to low-frequency leakage caused by the vent. Here, in-situ audiometry was investigated for six receiver-in-canal hearing aids from different manufacturers through three experiments. In Experiment I, the hearing aid gain was measured to investigate whether corrections were implemented to the prescribed target gain. In Experiment II, the in-situ stimuli were recorded to investigate if corrections were directly incorporated to the delivered in-situ stimulus. Finally, in Experiment III, hearing thresholds using in-situ and conventional audiometry were measured with real patients wearing open-fit hearing aids. Results indicated that (1) the hearing aid gain remained unaffected when measured with in-situ or conventional audiometry for all open-fit measurements, (2) the in-situ stimuli were adjusted for up to 30 dB at frequencies below 1000 Hz for all open-fit hearing aids except one, which also recommends the use of closed domes for all in-situ measurements, and (3) the mean interparticipant threshold difference fell within 5 dB for frequencies between 250 and 6000 Hz. The results clearly indicated that modern measured in-situ thresholds align (within 5 dB) with conventional thresholds measured, indicating the potential of in-situ audiometry for remote hearing care.

Ambient Noise in Candidate Rooms for User-Operated Audiometry

Hearing loss is a widespread problem while treatment is not always accessible, mainly because of the limited availability of hearing care professionals and clinics. In this work, part of the User-Operated Audiometry project, we investigate the acoustic environment of inexpensive non-sound-treated rooms that could be used for unsupervised audiometric testing. Measurements of 10 min of ambient noise were taken from 20 non-sound-treated rooms in libraries and private and public clinics, nine of which were measured twice. Ambient noise was compared against two traditional audiometric sound-treated rooms and Maximum Permissible Ambient noise levels by ISO 8231-1, while factoring for the attenuation by the DD450 circumaural headphones provided. In most non-sound-treated rooms, MPAs were violated only by transient sounds, while the floor-noise level was below MPAs. Non-sound-treated rooms' ambient noise levels presented with much larger fluctuations compared to sound-treated rooms. Almost all violations occurred at low to mid-low frequencies. Our results suggest that large-scale implementation of user-operated audiometry outside traditional audiometric rooms is possible, at least under some realizable conditions. Circumaural headphones' attenuation is probably a necessary condition for all cases. Depending on the room, an online system making decisions based on ambient noise might also be included in combination with active attenuation.

Audiometric Tests without Booths

Audiometric booths are used to reduce background noise levels at testing locations to below values specified in the standards. As such, they are considered inherent parts of the audiometric testing equipment. This paper presents the results from a literature search of solutions that could ensure that background noise levels are acceptable outside booths. The technology used is especially valuable for survey tests and for locations where booths are unavailable or cannot be used for different reasons. However, its use is recommendable for only screening hearing tests but not for clinical or research applications.

Rehearsal Sound Exposure and Choir Singers' Hearing: A Pilot Field Study

Exposure to high- and moderate-intensity sound is inevitable for professional singers during their working day, the majority of which is spent in rehearsal, preparing for a performance. The impact of self-produced sound exposure on singers' hearing within the rehearsal setting has not been examined.

OBJECTIVES

This original pilot field study investigates the feasibility of data collection and hypothesis testing of singers' hearing within the rehearsal environment.

METHODS

18 professional choir singers are examined for hearing threshold changes following routine rehearsal sound exposure. Pure Tone Audiometry is measured before, immediately after, and approximately 24 hours after rehearsal.

RESULTS

This study does not identify definitive Temporary Threshold Shift in this population under these conditions. That said, mean temporary threshold shift was found 3.61 dB higher than the recovery threshold shift in the right ear at 3000 Hz (P = 0.06), and this may be important to look at for future studies.

CONCLUSIONS

Methodological challenges of this field study include dynamic experimental conditions intrinsic to the rehearsal process, environmental and musical influence on Pure Tone Audiometry results and estimation of sound intensity exposure.

Hearing threshold of deaf pupils in Kaduna metropolis, Kaduna, Nigeria: A cross-sectional survey

Background

Hearing loss in paediatric age group may be inherited, developmental or caused by maternal rubella. It may also be due to complications at birth or certain infections such as meningitis and measles. Ototoxicity and exposure to excessive noise also contribute significantly. Majority of hearing loss in children can be prevented primarily. We aimed to share our findings on assessing the hearing thresholds of pupils in deaf schools in Northwestern Nigeria.

Participants and Methods

This was a cross-sectional study which assessed the hearing threshold of pupils in deaf schools in Kaduna metropolis, Kaduna, Nigeria. Approval was obtained from the State Ministry of Health Ethics Committee. Multi-staged sampling method was used to enrol 430 deaf pupils. Consent was obtained and a structured pre-tested questionnaire was used to generate data on the participant's biodata, history and detailed examination findings as well as pure-tone audiometry. Collated data were documented and entered into Statistical Product and Service Solutions version 20 for windows then analysed.

Results

Mean pure-tone average of the right ear was 103.4 ± 8.3 and the left ear was 104.3 ± 8.9. Majority had bilateral profound hearing loss (99.0%). Severe hearing loss was seen in 0.9%, whereas the remaining 0.1% had moderate hearing loss. The hearing loss sensorineural in majority (97.6%) and the remaining 2.4% had mixed hearing loss. High-frequency hearing loss predominated (98.6%).

Conclusion

Majority of the deaf pupils had bilateral, profound, sensorineural hearing loss, involving higher frequencies.

Disorders induced by direct occupational exposure to noise: Systematic review

Background:

To review the available scientific literature about the effects on health by occupational exposure to noise.

Materials and Methods:

A systematic review of the retrieved scientific literature from the databases MEDLINE (via PubMed), ISI-Web of Knowledge (Institute for Scientific Information), Cochrane Library Plus, SCOPUS, and SciELO (collection of scientific journals) was conducted. The following terms were used as descriptors and were searched in free text: “Noise, Occupational,” “Occupational Exposure,” and “Occupational Disease.” The following limits were considered: “Humans,” “Adult (more than 18 years),” and “Comparative Studies.”

Results:

A total of 281 references were retrieved, and after applying inclusion/exclusion criteria, 25 articles were selected. Of these selected articles, 19 studies provided information about hearing disturbance, four on cardiovascular disorders, one regarding respiratory alteration, and one on other disorders.

Conclusions:

It can be interpreted that the exposure to noise causes alterations in humans with different relevant outcomes, and therefore appropriate security measures in the work environment must be employed to minimize such an exposure and thereby to reduce the number of associated disorders.

Hearing Tests on Mobile Devices: Evaluation of the Reference Sound Level by Means of Biological Calibration

Background

Hearing tests carried out in home setting by means of mobile devices require previous calibration of the reference sound level. Mobile devices with bundled headphones create a possibility of applying the predefined level for a particular model as an alternative to calibrating each device separately.

Objective

The objective of this study was to determine the reference sound level for sets composed of a mobile device and bundled headphones.

Methods

Reference sound levels for Android-based mobile devices were determined using an open access mobile phone app by means of biological calibration, that is, in relation to the normal-hearing threshold. The examinations were conducted in 2 groups: an uncontrolled and a controlled one. In the uncontrolled group, the fully automated self-measurements were carried out in home conditions by 18- to 35-year-old subjects, without prior hearing problems, recruited online. Calibration was conducted as a preliminary step in preparation for further examination. In the controlled group, audiologist-assisted examinations were performed in a sound booth, on normal-hearing subjects verified through pure-tone audiometry, recruited offline from among the workers and patients of the clinic. In both the groups, the reference sound levels were determined on a subject’s mobile device using the Bekesy audiometry. The reference sound levels were compared between the groups. Intramodel and intermodel analyses were carried out as well.

Results

In the uncontrolled group, 8988 calibrations were conducted on 8620 different devices representing 2040 models. In the controlled group, 158 calibrations (test and retest) were conducted on 79 devices representing 50 models. Result analysis was performed for 10 most frequently used models in both the groups. The difference in reference sound levels between uncontrolled and controlled groups was 1.50 dB (SD 4.42). The mean SD of the reference sound level determined for devices within the same model was 4.03 dB (95% CI 3.93-4.11). Statistically significant differences were found across models.

Conclusions

Reference sound levels determined in the uncontrolled group are comparable to the values obtained in the controlled group. This validates the use of biological calibration in the uncontrolled group for determining the predefined reference sound level for new devices. Moreover, due to a relatively small deviation of the reference sound level for devices of the same model, it is feasible to conduct hearing screening on devices calibrated with the predefined reference sound level.

Dual Sensory Impairment among Community Dwelling Rural Elderly: Concern for Rehabilitation

Background. There is an increase in dual sensory impairment (DSI) (hearing and visual) with increase in elderly population. Most causes of DSI among elderly are treatable. This study determines the prevalence and characteristics of dual sensory impairment among elderly of a rural community. Material and Methods. A cross-sectional study conducted among 175 rural elderly. Visual acuity for distant vision was measured using Snellen E chart. Hearing ability was measured using pure tone audiometry. Results. The prevalence of hearing impairment was 72% and that of visual impairment was 48%. The overall prevalence of DSI among the study subjects was 17.7% and 32.6% depending on whether traditional pure tone average or high-frequency pure tone average was used to define moderate or worse degree of hearing impairment. DSI prevalence increased significantly with increase in age. DSI was higher among widow/ers and illiterates, who did not have any source of income and those who were financially dependent on others compared to their counter groups. Conclusion. Prevalence of DSI is high among community dwelling rural Indian elderly. Individuals with DSI produce unique challenges in rehabilitation. A team approach at primary health care level is necessary to diagnose and rehabilitate elderly thereby enabling them to easily lead an independent life.

AUTOMATED SCREENING AUDIOMETRY IN THE DIGITAL AGE: EXPLORING UHEAR™ AND ITS USE IN A RESOURCE-STRICKEN DEVELOPING COUNTRY

Background: The current study aimed to determine the accuracy of UHear™, a downloadable audiometer on to an iPod Touch©, when compared with conventional audiometry.

Methods: Participants were enrolled primary school scholars. A total number of eighty-six participants (172 ears) were included. Of these eighty-six participants, forty-four were female and forty-two were male; with the age ranging from 8 years to 10 years (mean age, 9.0 years). Each participant underwent two audiological screening evaluations; one by means of conventional audiometry and the other by means of UHear™. Otoscopy and tympanometry was performed on each participant to determine status of their outer and middle ear before each participant undergoing pure tone air conduction screening by means of conventional audiometer and UHear™. The lowest audible hearing thresholds from each participant were obtained at conventional frequencies.

Results: Using the Paired t-test, it was determined that there was a significant statistical difference between hearing screening thresholds obtained from conventional audiometry and UHear™. The screening thresholds obtained from UHear™ were significantly elevated (worse) in comparison to conventional audiometry. The difference in thresholds may be attributed to differences in transducers used, ambient noise levels and lack of calibration of UHear™.

Conclusion: The UHear™ is not as accurate as conventional audiometry in determining hearing thresholds during screening of school-aged children. Caution needs to be exercised when using such measures and research evidence needs to be established before they can be endorsed and used with the general public.

Validation of the use of self-reported hearing loss and the Hearing Handicap Inventory for elderly among rural Indian elderly population

Hearing loss is a potentially disabling problem among elderly leading to physical and social dysfunction. Though audiometric assessment of hearing loss is considered as gold standard, it is not feasible in community settings. Several questionnaires measuring hearing handicap have been developed. Knowledge regarding applicability of these questionnaires among rural elderly is limited, hence a study was planned to validate single question and Shortened Hearing Handicap Inventory for Elderly (HHIE-S) in detecting hearing loss against pure tone-audiometry among rural Indian elderly. A single question 'do you feel you have a hearing loss?' and the HHIE-S was administered to 175 elderly in two rural areas. Hearing ability was assessed using pure tone audiometry. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of both screening tools were compared with pure tone averages (PTAs) greater than 25, 40 and 55 dB hearing level (mild, moderate and severe hearing loss, respectively). The single question yielded low sensitivity (30.9%) and high specificity (93.9%) for mild hearing loss. Similarly HHIE-S yielded a sensitivity of 26.2% and specificity of 95.9%. Sensitivity with single question increased to 76.2% and specificity decreased to 83.1% with severe hearing loss. Sensitivity with HHIE-S also increased to 76.2% and specificity decreased to 87.7% with severe hearing loss. These hearing screening questionnaires will be useful in identifying more disabling hearing losses among rural elderly which helps in rehabilitation services planning.

Deterioration of noise-induced hearing loss among bottling factory workers

Background:

Repeated exposure to excessive noise will eventually lead to an irreversible increase in hearing thresholds. In theory, the damage reflects both the intensity of the noise and the duration of exposure. This is not linear with respect to duration of exposure; rather, the worker may experience a disproportionate loss in the early years of exposure.

Methods:

A prospective study surveying workers of the production section (i.e. most noise-exposed area) of a bottling factory was carried out in December 2003 and in December 2005. A self-administered questionnaire was used to extract information about worker's demographic characteristics, drug intake, and medical and occupational history, as well as information on the use of hearing protection devices. Noise mapping of the various departments of the factory was carried out. Otological examination, tympanometry and audiometry were also carried out on selected subjects.

Results:

Eighty-four workers, 76 (90.5 per cent) men and eight (9.5 per cent) women, were studied. Their mean age was 33.0 ± 7.6 years in 2003 and 35.0 ± 7.6 years in 2005. The recorded noise levels in the factory production section ranged between 91.5 and 98.7 dBA. The prevalence of sensorineural hearing loss among workers was noted to be 64.9 and 86.9 per cent for test one (2003) and test two (2005), respectively. The degree of hearing deterioration within the two years of this study was 1.0–3.2 dB for the right ear and 1.6–3.4 dB for the left ear. This deterioration was at discrete frequencies. More than half (53.6 per cent) of the workers did not have a hearing protection device. Of the 46.4 per cent who did, only 38.5 per cent claimed to have used it regularly.

Interpretation:

These findings showed that there was a high prevalence of mild sensorineural hearing loss and significant hearing deterioration among workers, due to exposure to excessive noise over a two-year period. The study demonstrates the practical importance of serial audiometry for noise-exposed workers as a means of monitoring hearing deterioration. It is necessary to enforce existing occupational health laws in our industries in order to prevent noise-induced hearing loss, since it is eminently preventable.

Occupational noise exposure and sensorineural hearing loss among workers of a steel rolling mill

Hearing loss is one of the most common chronic health conditions and has important implications for the patient's quality of life. However, hearing loss is substantially underestimated and under treated. The purpose of this study was to determine the prevalence of sensorineural hearing loss among the workers in a steel rolling mill in Nigeria. Each of the 150 randomly selected subjects had a structured questionnaire administered to them, followed by a full otological examination. Of these, 116 had tympanometry and pure-tone audiometry. Also a noise mapping of their respective work units was done. The workers were exposed to noise levels varying from 49 to 93 dBA. About 28.2% of the 103 who had their audiogram analysed had mild to moderate sensorineural hearing loss in their better ear and 56.8% of them had mild to moderate sensorineural hearing loss in their worse ear. The pure-tone average and the average hearing thresholds at 4 kHz for the groups significantly increased with an increasing noise exposure level. The prevalence of sensorineural hearing loss among the study population is high; and noise exposure is at least contributory. Pre-employment and regular audiometry while on the job is highly recommended.