Abstract
Audiologists are hearing healthcare specialists dedicated to the rehabilitation of individuals with hearing loss by prescribing the appropriate amplification devices. The process of choosing and fitting hearing aids involves several steps for which standardized guidelines have been issued. The aim of the present investigation was to evaluate the patterns of practice employed by Indian audiologists in the evaluation and fitting of hearing aids for adults. The survey was conducted using an Online questionnaire and distributed to Audiologists practicing in different parts of India via Google form link between April-August 2020. In all, 158 Audiologists participated in the study. The questionnaire consisted of 48 questions distributed over seven domains which included Respondent’s Profile, Hearing aid fitting experience with Adults, Assessment protocols, Hearing aid selection, Hearing aid fitting, Hearing aid verification, and Skills and Confidence levels of Audiologists. The findings of the study revealed varying practice trends, particularly during the stages of hearing aid verification and validation. There were also differences in the Audiologists’ proficiency and confidence in carrying out the various stages of fitting hearing aids.
Keywords: Practice trends, Hearing aid fitting, Hearing aid selection, Hearing aid verification, Hearing aid validation
Introduction
Hearing loss in adults can occur as a mixed effect of aging, disease, heredity, and noise. This can have an impact on their ability to exchange information and therefore cause isolation, dependence, frustration, as well as communication breakdown [1].
Hearing aids are amplification devices that are the primary management options for individuals with hearing impairment and are fitted by a licensed Audiologist who are hearing healthcare professional managing all the aspects of hearing loss assessment and rehabilitation. To achieve this, Professional organizations in the field of Audiology have clearly set up standardized guidelines for the assessment and fitting of hearing aids for adults with hearing loss which is to be followed uniformly by all Audiologists [2–4]. However, literature review on practice trends in many Western countries as well as those conducted in India point to the contrary. A 2018 research survey done in the United States revealed diversity among Audiologists in the procedure of fine-tuning and fitting of hearing aids [5]. Similar results were observed in a 2019 survey carried out in Malaysia which focused on paediatric practices in the area of probe microphone measures [6]. In the Indian scenario, Easwar et al. [7] surveyed Audiological practice trends in India and concluded that diversity in hearing aid practices exists among Indian audiologists [7]. Based on the above data, it can be observed that, despite the availability of standard guidelines and recommendations, a lack of uniformity in hearing aid assessment and fitting was observed. The data collected from the Indian Audiologists to assess hearing aid fitting practices was carried out in 2013. Over time, with technological advancements and revisions in practice guidelines, there is a need to revisit these trends in Indian Audiologists’ practices in selecting and fitting hearing aids.
The current study was undertaken to evaluate the current trends in hearing aid fitting practices among Indian audiologists for Adults with hearing impairments. Additionally, the study also examined the skills and confidence levels of the Audiologists to remain apprised of the latest trends.
Methodology
A total of 158 Audiologists in the age range of 23–52 years (Mean = 28.3 and SD = 4.58) participated in the current survey. The contact details of the Audiologists were collected from the State and National level Speech and Hearing groups as well as publicly available membership directories. A well-structured questionnaire was developed in Indian English in order to understand adult hearing aid fitting practices among Indian Audiologists. The questionnaire was converted to Google Forms (Google Inc., Mountain View, CA, USA) and a Google link was prepared to distribute the said questionnaire to Audiologists practicing all over India. Audiologists who worked in various Indian hospitals, clinics, and institutions and had a minimum of a Bachelor’s degree in Speech and Hearing, as well as a year of experience in fitting and assessing assistive technology, were eligible to participate in the study.
The questionnaire consisted of 48 questions distributed over seven domains which included Respondent’s Profile, Hearing aid fitting experience with Adults, Assessment protocols, Hearing aid selection, Hearing aid fitting, Hearing aid verification, Validation, and Skills and confidence of the Audiologists in performing the tests. The majority of the questions were multiple-choice while few were binary in nature, and the “others” option was included in the questionnaire for the participants in order to prevent the bias that comes with a preconceived selection of options. The questions were refined based on their relevance to the Indian context. Double-barrelled and ambiguous questions were avoided.
The questions were constructed by reviewing the practice guidelines and protocols for fitting amplification devices in adults given by organizations such as the American Speech-Language-Hearing Association (ASHA) [2]; and American Academy of Audiology (AAA) [3, 4] as well as survey studies on best practice guidelines carried out in different countries. A few questions were adapted from a study carried out by Amri, Quar & Chong which examined current paediatric amplification practices among audiologists in Malaysia [6]. A consent letter was obtained from the respective authors for this purpose.
To establish the content validity of the developed questionnaire, three Audiologists with a minimum experience of five years in Adult hearing aid assessment and fitting were asked to evaluate the questionnaire using a five-point rating scale (1- completely relevant, 2-somewhat relevant, 3-not sure, 4-somewhat irrelevant, 5- completely irrelevant) for its relevance to the study objectives. Completely relevant questions were deemed to be a part of the final questionnaire, whereas questions that were only marginally relevant or irrelevant were removed.
Questions in the Respondent Profile domain addressed the level of education, total years of practice, and place of practice of the Audiologists. Questions in the Hearing aid fitting experience with Adults domain included the Audiologists’ adult caseloads in terms of number, age group, degree of loss, type of loss referral sources, etc. They were also queried concerning their training in adult hearing aid assessment and fitting. Questions in the Hearing aid Assessment domain were concerned with the assessment procedures followed by the Audiologists while assessing the adult population in India. This included the testing time, calibration, availability of equipment, and test protocol used. Questions in the Hearing aid selection and fitting domain address the style of hearing aids prescribed, the technology used in hearing aids, prescription rules as well as other factors influencing hearing aid fitting. Questions in the Hearing aid verification and validation domains highlight the choice of verification and validation methods used by the Audiologists while assessing adults with hearing loss. The domain on skills and confidence rates the confidence levels of Audiologists in performing adult hearing assessment, hearing aid fitting and selection, verification and validation.
Results and Discussion
Results of the current survey are discussed in detail under the seven domains.
Respondent Profile
According to the responses from the 158 audiologists, 104 respondents had between one and five years of professional experience (66.4%) and 74 of them had a bachelor’s degree in Audiology and Speech-Language Pathology (46.8%). In addition, 53 Audiologists (33.5%) worked in private therapeutic settings, making up the majority of the sample. Hospital establishments (20.8%, 33 Audiologists) and educational institutions (16.4%, 26 Audiologists) were next. It was interesting to see that nearly 45 Audiologists among 158 of respondents (28.4%) were practicing in multiple work setups at the same time. These comprised private clinics and hospitals; hospitals and institutes; private clinics and private institutes; or private institutes and hearing aid companies. In contrast, the majority of respondents to a US study (75%) had more than ten years of experience [5]. Compared to hospitals and other institutions, the majority of respondents in this survey worked in private clinics. This outcome is consistent with the survey that Easwar et al. conducted [7]. As the majority of Indian audiologists, worked in numerous setups, it increases their understanding of the medical conditions linked to hearing loss as well as potential treatment choices. This helps provide clients with hearing impairment with appropriate counseling.
Hearing Aid Fitting Experience with Adult Patients
More than fifty persons were evaluated in a month, according to 41.2% (65 Audiologists) of respondents. It was also discovered that most Audiologists regularly fitted hearing aids to people of all ages, followed by those of 55 years of age or older and between the ages of 36 and 55 years. The most common types and degrees of hearing loss that audiologists encountered were sensorineural (81.6%, 129 Audiologists) and moderately severe to severe (84.2%, 133 Audiologists), respectively. The Otorhinolaryngologist, general physician, and word-of-mouth were the main sources of patient referrals. Pediatricians and neurologists referred very few patients. In addition, it was observed that 125 respondents (79.1%) reported undergoing training in hearing aid assessment and fitting as part of their graduate or master’s degree program. Others reported attending workshops, seminars, or training by the hearing aid manufacturers while on the job as their learning source. As per the survey results, the majority of Audiologists have a substantial caseload due to the general public’s use of social media and search engines like Google which has increased awareness regarding hearing loss. As the majority of the referrals were made by general physicians and ENTs, it demonstrates that in order for Audiologists to operate as independent practitioners, awareness needs to be created among other medical disciplines to improve upon the referral rates.
Assessment
The findings demonstrated that the majority of Audiologists can finish all evaluation procedures for an adult patient in a single session. Additionally, it was found that subjective calibration was performed every day and objective calibration of the equipment was performed at most establishments once a year. Table 1 represents the equipment available with the Audiologists. The majority worked with an Audiometer, an Immittance meter, an Otoacoustic emission (OAE) apparatus, and an Auditory Brainstem Response (ABR).
Table 1.
Frequency distribution of equipment available at work place
| What are the instruments available for adult hearing assessment in your work setup | No of respondents | Percent |
|---|---|---|
| Audiometer | 25 | 15.8 |
| Audiometer, immittance | 26 | 16.4 |
| Audiometer, immittance, ABR | 4 | 2.5 |
| Audiometer, immittance, OAE | 3 | 2.5 |
| Audiometer, immittance, OAE, ABR | 51 | 32.2 |
| Audiometer, immittance, OAE, ABR, VEMP | 37 | 23.4 |
| Audiometer, immittance, OAE, ABR, VEMP, EcochG | 1 | 0.6 |
| Audiometer, immittance, OAE, ABR, VEMP, ENG, EcochG | 1 | 0.6 |
| Audiometer, immittance, OAE, ABR, VEMP, high evoked potentials, Real ear measures | 1 | 0.6 |
| Audiometer, immittance, OAE, ABR, VEMP, real ear measurements | 1 | 0.6 |
| Audiometer, immittance, OAE, ABR, VEMP, VNG | 1 | 0.6 |
| Audiometer, immittance, OAE, ABR, VEMP, VNG, VHIT | 2 | 1.3 |
| Audiometer, immittance, OAE, ABR, VEMP, VRA, FFA, BOA | 1 | 0.6 |
| Audiometer, immittance, OAE, ABR, ASSR | 1 | 0.6 |
| Audiometer, immittance, OAE, ABR, special test also available | 1 | 0.6 |
| Audiometer, Immittance, OAE, ABR, VNG | 1 | 0.6 |
| Audiometer, OAE | 1 | 0.6 |
| Total | 158 | 100 |
Only a small number of Audiologists possessed additional equipment for conducting Vestibular Evoked Myogenic Potential (VEMP), Electrocochleography (EcochG), and Auditory Steady State Response (ASSR). When assessing adult patients, Audiologists typically use a test procedure like Pure Tone and Speech Audiometry, followed by Immittance (Table 2).
Table 2.
Tests conducted by Audiologists while assessing adult patients
| Tests used by an audiologists while assessing adult patients | No of respondents | Percentage (%) |
|---|---|---|
| Pure tone audiometry | 157 | 99.4 |
| Speech audiometry | 116 | 73.4 |
| Speech in noise test | 34 | 21.5 |
| Speech intelligibility index | 19 | 12 |
| Uncomfortable level | 81 | 51.3 |
| Most comfortable level | 67 | 42.4 |
| Threshold equalizing noise test | 4 | 2.5 |
| Acceptable noise level | 1 | 0.6 |
| Special tests | 54 | 34.2 |
| Tinnitus assessment | 51 | 32.3 |
| Otoacoustic emission | 60 | 38 |
| Immittance audiometry | 114 | 72.2 |
| Auditory brainstem response | 57 | 36.1 |
| Vestibular evoked myogenic potential | 11 | 7 |
Of the Audiologists surveyed, about 137 (86.7%) said they had access to a sound field testing facility, while the remaining didn’t. These factors could make it more difficult for Audiologists to adhere to standard evidence-based practice guidelines. Adults’ ability to perceive speech was assessed through the use of measures such as speech detection thresholds, speech discrimination scores, and/or speech recognition thresholds. Only a small number of people used the Speech in Noise (SPIN) test. According to survey results, among 158 respondents, 99 (62.7%) performed daily listening checks while 127 (80.3%) of them performed objective calibration once a year which is higher in comparison to the survey by Easwer et al., wherein the percentages were 48.7% and 52.26%, respectively [7]. However, there were discrepancies in the tests used by Audiologists on adult clients; 20 (12.6%) of them stated that they exclusively used Puretone Audiometry as a clinical test. Even essential tests like speech audiometry, which is necessary to verify the outcomes of hearing aid benefits were omitted. Subsequent findings showed that nearly 28% (45 Audiologists) do not use immittance audiometry to evaluate patients. This finding aligns with a survey by Easwar and colleagues, which hypothesized that Audiologists might forego middle ear assessments given the costs borne by patients [7]. Regarding instrument availability, over 30% of Audiologists (48 respondents) did not have ABR, OAE, or VEMP at their workplace, which may hinder them from providing comprehensive assessments. This finding is corroborated by a South African study that found that ABR testing in public health care was frequently excluded from minimum diagnostic test batteries due to instrument unavailability [8]. This could be attributed to the cost of the equipment.
Hearing Aid Selection and Fitting
Among 158 respondents, 125 (79.1%) of them prefer to recommend bilateral fittings for adults with bilateral hearing loss. Regarding the technology of hearing aids, 142 (89.9%) of the participants indicated that digital devices were their preferred option. In terms of design, the most popular types of aids were behind-the-ear (BTE), followed by the receiver in the canal (RIC) and in-the-ear (ITE). Additionally, it was discovered that 42 (26.6%) Audiologists choose devices with 2–4 channels, 85 (53.8%) with 5–8 channels, and 26 (16.4%) Audiologists recommend > 10 channels. In response to the factors influencing hearing aid selections, the majority indicated degree of hearing loss, client preference, hearing aid features, and their comfort and experience with the device as the major factors. A total of 70 (44.3%) respondents suggested recommending earmolds with hearing aids for all patients, compared to 64 (40.5%) who did so occasionally and 12(7.7%) who did so infrequently. Furthermore, the majority of respondents choose the manufacturer’s first fit, followed by NAL-NL 1/2 and DSL for initial gain settings. Owing to recent technological developments, the survey included inquiries about the extra features that audiologists turned on for the adult population (Table 3).
Table 3.
Hearing aid features manipulated by Audiologists
| Extra modification audiologists make in hearing aid software during the initial fitting | No of respondents | Percentage (%) |
|---|---|---|
| Turn on noise cancellation | 98 | 62.02 |
| Turn on volume control | 63 | 39.9 |
| Modification suggested by manufacturer’s First fit | 57 | 36.1 |
| Activate compression | 55 | 34.8 |
| Turn on directional microphone | 49 | 31 |
| Turn off volume control | 34 | 21.5 |
| Turn on the omnidirectional microphone | 28 | 17.7 |
| Turn off noise cancellation | 11 | 7 |
| Depends on patients’ preferences and problems | 5 | 0.03 |
The majority of audiologists recommended either a vent or an earmold as acoustic adjustments followed by the bore and damper. Most Audiologists tested at least one or two hearing aids; a small percentage tried three to four hearing aids, or at least two from various manufacturers with distinct technologies prior to final prescription. A total of 139 (88%) Audiologists suggested mandatory follow-up appointments. The variables considered while fine-tuning included patient complaints, handicap questionnaires, aided pure tone thresholds and speech scores, and probe microphone measurements. The parameters adjusted during fine tuning were gain, feedback management system, noise algorithms, and compression ratio. Majority of the Audiologists turned on the data logging option. Of the respondents, 41.7% (66 Audiologists) gave verbal counseling regarding the use, maintenance, and care of their hearing aids; 56.3% (89 Audiologists) said they used both written and spoken manuals for counseling, and 3 Audiologists said they only utilized written manuals. In comparison to the survey conducted by Easwar and colleagues, it was found that the proportion of Audiologists who prescribed body-level hearing aids had dropped from 13% to 1.9% [7]. This can be attributed to advancements in hearing aid technology over time. Additionally, research by Anderson and associates revealed that Audiologists were not as likely to take into account patient characteristics outside of the Audiogram [5]. More over half of the Audiologists said they used the manufacturer’s first fit for the initial gain, which is more than the 35% reported in the study by Anderson and colleagues [5]. Nonetheless, research has demonstrated that programming with prescriptive formulas like NAL and DSL yield better self-perceived benefit [5]. The survey overall revealed numerous best practices that audiologists adhere to, like mandating follow-up appointments and testing the wearer’s ability to hear over the phone and in noisy environments.
Hearing Aid Verification
The results revealed that 117 of the respondents (74.7%) relied solely on informal questions to verify the benefit of the hearing aids. 18 Audiologists reported pairing informal questions with tests such as the Aided audiogram, articulation index, Quick SIN™(Speech in noise), and insertion gain measurements (11.6%). The usage of objective metrics like Real ear measurement (REM) is marginally more than the 8.37% reported by Easwer and colleagues [7]. In Anderson’s study, the percentages were greater (50%) [5]. A small percentage of respondents did not perform any official tests to confirm hearing aid fitting.
Hearing Aid Validation
According to the survey data, only 54 (34.2%) audiologists carried out the validation procedure. The majority of audiologists employed self-assessment of communication as one of the validation measures. This percentage is higher than the data by Easwer and colleagues [7].
Skills and Confidence levels
The findings showed that most Audiologists had a high level of confidence in their abilities to perform hearing evaluation procedures, as well as the selection and fitting of hearing aids. However, this trend reversed when it came to the verification of hearing aids using real ear measurements, wherein the majority of the Audiologists lacked confidence and needed assistance. 58 Audiologists (36.7%) attributed this to a lack of equipment at work, 22 Audiologists (13.9%) attributed this to inadequate training, and the remaining had only a theoretical background of the procedure.
When respondents were asked if the academic and clinical training they received during their bachelor’s and master’s degrees was sufficient for practicing hearing aid fitting in Adults, the response was mixed; about 48 Audiologists (30.3%) thought it was, 60 (37.9%) said it was only partially adequate and 45 (28.4%) said it was inadequate. In addition, the Audiologists were asked to recommend changes to the curriculum in order to enhance their clinical knowledge and proficiency in the assessment and fitting of adult hearing aids. Of those who responded, 146 (92.4%) recommended increasing the amount of hands-on experience included in the bachelor’s and master’s degree programs, and 63 Audiologists (39.9%) suggested adding seminars and conferences in addition to the increased amount of hands-on experience. Furthermore, the majority of respondents stated that they attend conferences as working professionals to stay up to date on the most recent technological advancements in hearing devices. An additional observation was that it was noticed that Audiologists who worked in multiple setups gave a uniform response. They were more confident in doing the assessment, fitting, and verification of hearing aids. This can be due to better opportunities to see a wide variety of patients as well as obtain input from the other departments such as ENT, Radiology etc. These interactions and facilities might help them to improve their skills and can influence their decision-making during assessment and rehabilitation process.
Implications of the Study
The Current study provides suggestions to fill in the gaps between theoretical knowledge versus the practical applications. Further, the results of the survey can be used as a baseline to improve inconsistencies in practices. In comparison to earlier studies, improvements were noted in the following areas.
Higher number of respondents performed subjective and objective calibration of Audiological equipment on a regular basis
Majority of respondents recommended digital hearing aids in comparison to body level hearing aids
More number of respondents have started using objective metrics such as Real ear measurements to verify hearing aid fitting along with subjective metrics.
Higher number of respondents have started using questionnaires for validation of hearing aid fitting.
Study Limitations
Responses were taken from work setups in urban areas, the results of the survey cannot be generalized to the rural setups where the requirements are different. As India is a vast country it was not possible to collect a representative sample from every region. Since it is a questionnaire-based survey, subject bias may influence the study results.
Conclusion
The majority of respondents, according to the current study, completed the evaluation and fitting of hearing aids in compliance with the established guidelines. However, there is scope for further improvements in the areas of verification and validation stages of hearing aid fitting, wherein the majority of the Audiologists did not use the real ear measurement procedures and validation questionnaire. The Audiologists working in private set up must also add additional tests to provide more comprehensive hearing care services. Furthermore, it is imperative to raise awareness and encourage practical experience and exposure to the profession for aspiring audiologists in order to enhance their clinical abilities and self-assurance, ultimately leading to higher practice standards. To conclude, the survey highlights the significance of rebuilding and revisiting the practice patterns being followed by Audiologists in the Indian setting on a regular basis to provide standardized patterns of assessment to Adult patients with hearing loss.
Acknowledgements
We Thank the Director of Samvaad Institute of Speech and Hearing for permitting us to conduct this study and the participants of this survey.
Funding
No funding was received to assist with the preparation of this manuscript.
Declarations
Conflict of interest
The authors have no competing interests to declare that are relevant to the content of this article.
Footnotes
Publisher's Note
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