|Year : 2020 | Volume
| Issue : 2 | Page : 88-96
Verification and validation measures of hearing aid outcome: Audiologists' practice in Saudi Arabia
Ahmad A Alanazi
Department of Audiology and Speech Pathology, College of Applied Medical Sciences, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
|Date of Submission||12-Feb-2020|
|Date of Decision||27-Jun-2020|
|Date of Acceptance||22-Jul-2020|
|Date of Web Publication||19-Aug-2020|
Ahmad A Alanazi
College of Applied Medical Sciences, King Saud Bin Abdulaziz University for Health Sciences, P.O. Box 3660, Riyadh, 11481 Mail Code 3129
Source of Support: None, Conflict of Interest: None
Background: The best practice guidelines require verification and validation measurements for fitting hearing-impaired patients with hearing aids (HAs). The clinical practice for verifying and validating HAs fitting in Saudi Arabia (SA) is unknown. Objectives: This study aimed to examine how audiologists verify and validate HAs fitting in SA. Materials and Methods: A convenience cross-sectional descriptive study design was used to address the aim of the study. An online-validated questionnaire was prepared and electronically distributed to reach a large number of practicing audiologists in SA. The questionnaire consisted of 16 close-ended questions and primarily focused on two categories demographic information and HAs fitting. Results: A total of 80 audiologists completed the questionnaire. The majority of participants were female (66.3%), from the central region (71.2%), worked in governmental hospitals (65%) with both adult and pediatric patients, and had different academic qualifications and teaching experiences. Audiologists (98.2%) mainly relied on the patient's feedback and the functional gain to verify HAs fitting. More than half of the participants either never or rarely used real ear measurements and coupler-based measurements. Unstructured general questions were mostly used by 65.5% of audiologists to validate fittings. The lack of equipment, time, and proper training were the core reasons for not following the best practice approach for fitting HAs. Conclusions: Verification and validation provide audiologists with confidence that their patients satisfy with HAs. Employers need to equip audiology clinics with HAs verification systems, allow more time-slots for HAs fitting cases and support up-to-date training for audiologists. To encourage validating HAs fitting regularly, audiologists are advised either to utilize already existed Arabic validation tools or to translate and validate other tools in English.
Keywords: Audiologists, hearing aids, real-ear measurements, validation, verification
|How to cite this article:|
Alanazi AA. Verification and validation measures of hearing aid outcome: Audiologists' practice in Saudi Arabia. Saudi J Health Sci 2020;9:88-96
| Introduction|| |
Audiologists provide evidence-based hearing and balance healthcare for adults and children. Currently, around 432 million adults and 34 million children have hearing loss worldwide. The number of people with disabling hearing loss is expected to exceed 900 million people (one out of every 10 people) by 2050. According to the General Authority for Statistics in Saudi Arabia (SA), 1% of all citizens have mild hearing loss, and 0.4% of them have severe and profound hearing difficulties. To enable those with hearing loss to use auditory signals effectively and perform better speech communication, hearing aids (HAs) fitting is necessary for eligible patients. The primary function of HAs is to amplify sounds; however, HAs fitting for specific degrees and etiologies of hearing loss require important information than just the amplification of sound.
This information can be obtained via objective and subjective (i.e., verification and validation) measurements. The best practice guidelines from the American Speech-Language-Hearing Association (ASHA) and the American Academy of Audiology (AAA) require these measurements to ensure that HAs fitting was individualized to the patient's needs and consequently improve the (re) habilitation outcomes., When audiologists follow the best practice approach to fit HAs (e.g., identify the patient's eligibility for wearing HAs, recognize the patient's expectations, counsel the patient about available types of HAs, ensure the selected HAs are appropriate, and verify and validate fittings), the patient will receive the highest quality of services and has fewer postfitting adjustment visits.,,, Although verification and validation are different from each other, audiologists use them interchangeably.
Verification is an objective measure used to examine the performance of HAs in the ear (ITE) in terms of meeting measurable specifications. Verification aims to improve speech recognition, confirm that soft sounds are audible, and limit loud sounds to the patient's comfortable level. Verification is conducted at the initial HAs fitting session and follow-up visits when changes (e.g., adjustment or repair) to HAs affect the frequency response and output. Three major techniques are used for verifying HAs fitting: (a) real-ear measurements (REMs), also known as probe microphone measurements, (b) coupler-based measurements (CBMs), and (c) the functional gain, also called the sound field measure or the aided threshold.
REMs are used to check if the HA is meeting the targets (or output levels) as measured ITE canal. Several steps should be taken before and after performing REMs. For example, before performing REMs, the calibration of the probe microphone system and the small probe tube is necessary, and approximately 80–100 cm at 0° azimuth is the recommended speaker-to-patient distance., After the insertion of the probe tube into the patient's ear canal within 6–8 mm of the tympanic membrane, a few measurements, such as real ear unaided gain, real ear occluded gain, and real-ear insertion gain are performed. Valente et al. found in a double-blinded randomized crossover study that four out of five patients prefer REMs to verify HAs fittings compared with the HAs manufacturer's first-fit. They concluded that HAs should not be verified based on the first-fit alone without using REMs.
CBMs are another technique used for verifying HAs fitting when REMs are not practical such as with babies. The use of CBMs reduces patients' involvement in the verification process. The real-ear-to-coupler difference is the main CBM used to evaluate the difference between the coupler's response and the patient's ear canal response. Both REMs and CBMs are reliable and accurate procedures for (a) determining how well HAs are matching the prescription target based on certain formulae (e.g., National Acoustic Laboratory Non-linear [NAL-NL] and Desired Sensation Level, [DSL]), and (b) confirming that HAs do not exceed the patient's discomfort level.,
The third technique used for verifying HAs fitting is the functional gain, which is the difference between aided and unaided thresholds in the sound field using speech or tone testing signals. The use of the functional gain technique has some advantages, such as detect the softest sounds that the patient hears and exclude the possibility of non-organic hearing loss and auditory neuropathy., However, this technique, unlike REMs and CBMs, provides a limited resolution of frequencies and no information about real-ear maximum output levels. Kuk and Ludvigsen stated that “Despite its usefulness, the information provided by sound-field measures is not the same as that provided by probe microphone measures, especially in nonlinear HAs.” (p. 94) REMs are much more reliable than functional gain.
After the verification process, validate whether HAs are working for the patient is important. Validation is a subjective measure that examines the patient's benefits and satisfaction after using HAs. Several validation tools are available, such as the hearing handicap inventory for the elderly/adults (HHIE/A), the abbreviated profile of HA benefit (APHAB), the client-oriented scale of improvement (COSI), the satisfaction with amplification in daily life (SADL).,,, Furthermore, validation of HAs fitting can also be accomplished by using unaided and aided speech tests performed in the sound field.
Although the best practice guidelines from international organizations (e. g., ASHA, AAA) require verification and validation measurements for HAs fitting, several studied conducted to date have shown the limited use of these measurements. For example, Kirkwood found that 57% of HA dispensers had the REM equipment, but only 34% of them used it regularly. Mueller and Picou reported that 52% of audiologists and HA dispensers used REMs only sometimes. Less than one-third of all HA dispensers used REMs to verify fittings. The field of audiology in SA was established more than 30 years ago; however, data about the current practice of HAs fitting is limited. Therefore, this study aimed to examine how practicing audiologists verify and validate HAs fitting in SA. To the best of the author's knowledge, this is the first study to explore this practice in SA.
| Materials and Methods|| |
This convenience cross-sectional descriptive study was reviewed and approved by King Abdullah International Medical Research Center Institutional Review Board (protocol #RC19/383/R). The inclusion criteria were set to include all audiologists who were practicing in SA at the time of completing the questionnaire. Written informed consent was obtained from all voluntarily willing participants. Only complete questionnaires were considered.
A self-administered English questionnaire was prepared to achieve the aim of this study [Appendix 1]. This questionnaire used the framework of the pre-validated questionnaire by Alanazi and contained two main categories: (a) demographic information and (b) HAs fitting. The questionnaire's face validity was established by two independent experts. After the target population and questions needed to achieve the aim of study were defined, the expert panel decided on the questions content and wording. Any inadequate expressions or concepts were identified and resolved. Then, the questionnaire was pretested in a pilot study including five participants who received hard copies of the questionnaire. Before filling in and submitting the questionnaire, the pilot participants had to read and complete the informed consent that included necessary elements, such as the purpose of the research, the inclusion criteria, the benefits and risks, handling of data, contact information, etc. After the pilot study participants agreed to participate and completed the questionnaire, they were asked about the clarity of all questions to ensure that there was no misunderstanding of any question. All the pilot study participants had correct understanding of the questions, and no comments were received.
According to the results from the pilot study, the content of the questionnaire was not changed or modified. This questionnaire consisted of 16 close-ended questions that were distributed equally into the two categories. All the questions were mandatory with the availability to select more than one answer (or option) to some questions. The demographic information category included eight questions about the participants' gender, age, nationality, regional location, type of workplace, academic qualifications, years of experience, and the nature of the patient population (i.e., adults and/or children) being served. The HAs fitting category was designed to examine whether the participants fit HAs, types of the prescribed HAs, how the participants verified and validated HAs fitting, how often REMs and CBMs were used, what formula were used for fitting HAs, and what reasons hinder performing these measurements.
The questionnaire was created electronically on Google Forms (Google LLC, Mountain View, California, United States) to reach a large number of audiologists all over SA in a time-efficient and cost-effective way. The link to the questionnaire was distributed by E-mail to audiologist members of the Saudi Society of Speech-Language Pathology and Audiology (SSSPA) and posted on social networks (Twitter, Facebook, and WhatsApp). Similar process of the informed consent used with the pilot study participants was also used with the main study participants electronically. Two electronic reminders were sent consecutively a few weeks later. This link was accessible for approximately 3 months. Participation was voluntary, and answers were anonymous. Data were analyzed using descriptive statistics.
| Results|| |
A total of 80 audiologists participated in the study. No uncompleted questionnaires were received. The results of the questionnaire were included under the two categories listed in the material and methods section.
This section elaborates the background characteristics of the targeted population. Of the total participants, 76 (95%) audiologists were Saudi citizens, whereas the remaining participants were two Jordanian, one Kuwaiti, and one Indian. The greater proportion (n = 53; 66.3%) of audiologist participants were females, and age was distributed in four different ranges. Forty-eight (60%) participants were younger than 30 years old, 21 (26.3%) aged between 31 and 40 years, six (7.5%) belonged to the 41–50 age group, and five (6.3%) were older than 51 years. The majority of the participants (n = 57; 71.25%) worked in the central region of SA, nine (11.25%) in the Western region, eight (10%) in the eastern region, and six (7.5%) in the northern region. No participants were from the southern region.
Fifty-two (65%) participants were working in governmental hospitals, 21 (26.25%) in private practice (e. g., HA centers and private clinics), four (5%) in governmental rehabilitation centers (e. g., comprehensive rehabilitation centers that are run by the Ministry of Human Resource and Social Development), and three (3.75%) in universities and schools. Sixty-four (80%) participants served both adult and pediatric patients on a daily basis. Ten (12.5%) participants provided audiological services to adults alone, and six (7.5%) participants provided similar services to only children. Academic-qualifications wise, 60 (75%) participants held a bachelor's degree, 12 (15%) had a master's degree, six (7.5%) had a doctor of audiology (AuD) degree, and two (2.5%) had a doctor of philosophy (Ph.D.) degree. Different practice experiences were reported. Of the total, 47 (58.75%) participants had an experience ≤5 years, 15 (18.75%) participants had experience between 6 and 10 years, seven (8.75%) participants had up to 15 years of experience, and five (6.25%) participants had experience between 16 and 20 years. Only six (7.5%) participants had >20 years of experience in the field.
Hearing aids fitting
Fifty-eight (72.5%) participants answered “yes” to the question “are you fitting/dispensing HAs,” while the remaining participants said “no.” More than one type of HAs were fitted by the participant audiologists. Of the total participants who dispensed HAs, behind the ear (BTE) HAs were the most popular fitted type by 57 (98.2%) participants, followed by custom-made HAs. Completely-in-canal, in-the-canal, invisible-in-the-canal, in-the-ear (ITE), and microphone-in-helix (MIH) were fitted by 49 (84.5%) participants, whereas receiver in the canal and receiver ITE were fitted by 37 (63.8%) participants. Twenty-seven participants (46.5%) reported fitting bilateral/contralateral routing of signal (Bi/CROS) HAs. “Based on the patient's feedback” was the most selected answer to the question “how do you verify HAs fitting” by 57 (98.2%) participants, while 38 (65.5%) participants reported using the functional gain to verify HAs fitting. Only 26 (44.8%) participants used REMs, and 20 (34.4%) participants used CBMs to verify HAs fitting. Audiologist participants reported more than one answer to the same question, so percentages sum to more than 100%.
In response to the question “how often do you use REMs to verify and adjust the gain/output of the HA on the day of the fitting,” 21 (36.2%) participants “never” used REMs to verify and adjust the gain/output of the HA, and 13 (22.4%) participants “rarely” did. “Always,” “usual” and “sometimes” were selected equally by the remaining participants. Responses to the question “how often do you use CBMs to verify and adjust the gain/output of the HA on the day of the fitting?” were as follow: 23 (39.6%) participants “never” used CBMs to verify and adjust the gain/output of the HAs, 15 (25.8%) participants “rarely” used CBMs, and 13 (22.4%) participants “sometimes” did. [Figure 1] shows how often audiologists in SA used REMs and CBMs to verify HAs fitting.
|Figure 1: The distribution of the frequency use of real-ear measurements (REMs) and coupler-based measurements (CBMs) to verify hearing aids fitting by audiologists in Saudi Arabia. Not applicable: The percentage of audiologists who did not dispense hearing aids|
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In terms of HAs prescription formulae, NAL-NL and DSL were the most used by 46 (79.3%) and 40 (68.9%) participants, respectively. Eight (13.7%) participants reported using the manufacturer's fitting formulae, and five (8.6%) participants stated using the prescription of gain and maximum. Thirty-eight (65.5%) participants used unstructured general questions as a tool for validating HAs fitting, 15 (25.8%) participants utilized SADL, and ten (17.2%) participants used APHAB [Figure 2]. The last question was aimed to answer why audiologist participants did not conduct objective measurements, particularly REMs and CBMs. Thirty-two (55.2%) participants reported that the equipment was unavailable, 27 (46.5%) participants reported the lack of time, and 20 (34.5%) participants stated poor training hindered them from conducting these measurements [Figure 3].
|Figure 2: The distributions of tools used for validating hearing aids fitting by audiologists in Saudi Arabia. APHAB: Abbreviated Profile of Hearing Aid Benefit, SADL: Satisfaction with Amplification in Daily Life, HHIE/A: Hearing Handicap for the Elderly/Adults, COSI: Client Oriented Scale of Improvement. Audiologist participants reported more than one reason, so percentages sum to more than 100%|
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|Figure 3: The reasons for not using real-ear measurements and/ or coupler-based measurements by audiologists in Saudi Arabia. Audiologist participants reported more than one reason, so percentages sum to more than 100%|
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| Discussion|| |
This study explored how audiologists verify and validate HAs fitting in SA. The electronic questionnaire was distributed to a random sample of audiologists. The number of practicing audiologists in SA is unknown, but it is estimated around 240 audiologists. Eighty audiologists successfully completed the questionnaire.
The majority of participants were Saudi females from the central region, Riyadh. Presently, only two audiology programs exist in SA, particularly in Riyadh. Both programs are offered by King Saud University (KSU) and Princess Nourah bint Abdulrahman University (PNU), and are available for undergraduate students. This may explain why most audiologist participants had an undergraduate degree and worked in Riyadh with a few years of experience. Although the entry-level degree to practice audiology in SA is a bachelor's degree, Alanazi reported the need for establishing graduate audiology programs in Saudi universities where there is currently none. KSU offers the program for male and female students, and only 30% of students admitted into this program were males. PNU offers the program for female students only. Sullivan reported the ratio of female to male audiologists is approximately three to one. A few participants were from the northern region with no participation obtained from the southern region. This may elucidate the scarcity of audiological services in both regions.
Governmental hospitals are the most workplaces for audiologists in SA, in which they provide services to both adult and pediatric patients. More than 70% of audiologists in the United States are employed in clinical settings. The current study revealed that only three participants were working in schools and universities. Recruitment policies and the lack of understanding of professional services provided by audiologists are the main reasons behind this shortage. According to ASHA, approximately 8.4% and 7.2% of audiologists work in schools and universities, respectively. The primary stakeholders (e.g., Ministry of Health and Ministry of Education) need to understand the professional services provided by audiologists and hire more graduated audiologists in primary healthcare centers and schools in SA.
Hearing aids fitting
In response to HAs fitting, not all practicing audiologists in SA prescribed HAs. Of the total participants, 58 audiologists commonly fitted BTE HAs followed by custom-made HAs. BTE HAs are suitable for almost all types of hearing loss and frequently used for both children and adult patients. Most governmental hospitals, the common workplace for audiologists in SA, provide HAs free of charge for eligible patients who are either fitted with HAs in the clinic or sent to HA manufacturers for fitting. Only a few participants (17.5%) worked in private practice. Health insurance companies cover a great deal of the cost of HAs for beneficiaries who are treated in private healthcare settings in SA.
The present study revealed an inconsistent use of verification techniques and validation tools. The majority of practicing audiologists, regardless of their academic qualifications, relied on both the patient's feedback and the functional gain to verify and validate HAs fitting. Thirty-three participants “never” or “rarely” used REMs, and only a few of them “always” used REMs to verify and adjust the gain/output of HAs. Likely, 38 participants “never” or “rarely” used CBMs, and only a few of them used CBMs to verify and adjust the gain/output of HAs. The result is consistent with another study conducted by Alanazi that found more than 54% of practicing audiologists use the patient's feedback to verify hearing aid fittings in SA.
Several reasons were reported by the participants who “sometimes,” “rarely,” or “never” performed REMs and/or CBMs. The main reasons were: (a) the unavailability of equipment, (b) the lack of time, and (c) the poor training. Jorgensen stated that these reasons are mostly reported by audiologists; however, such reasons are not acceptable for not providing the highest quality of care to the patients. Employers are advised to make HAs verification systems available, allow more time-slot for HAs fitting cases, and support up-to-date training for audiologists. REMs, CBMs, and functional gain have advantages and disadvantages and cannot replace each other in terms of the information that each provides. For example, the use of verification measures during HAs fitting has been associated with improved patient outcomes. The functional gain permits audiologists to identify the benefit of amplification via measuring the lowest input level that is audible to the HAs user., Therefore, audiologists have to recognize the value of using each measure before discontinuing the use of one measure in favor of the other.
A few participants reported the use of the manufacturer's prescription formula (i.e., the first-fit formula) to deliver accurate fitting gains. Studies showed that the manufacturer's first-fit formulae are inadequate in providing appropriate gain.,, Aazh et al. found that approximately 71% (36 of 51) of HA fittings programmed to the manufacturer's quick fit approach resulted in ≥10 dB gain from target. Sanders et al. reported that the manufacturer's NAL-NL2 quick fits of five major HAs manufacturers presented less aided gain and reduced audibility compared to the NAL-NL2 prescriptive target provided by REMs. NAL-NL and DSL were the most prescription formulae used by the participants. This result is consistent with the trends observed in the literature., Fitting HAs according to prescribed target levels leads to more comfortable listening and improves intelligibility of speech compared to fittings that diverge from the target.,,
More than half of the participants used unstructured general questions as a tool for validating HAs fitting. Many validation tools (e.g., HHIE/A, APHAB, COSI and SADL) are available to identify the advantages of wearing HAs and recognize which communication situations cause frustration to patients. The majority of these tools were designed in the English language, but the Arabic language is the primary language of almost all patients being served. Although language differences may hinder participating audiologists from using such tools frequently, a few tools were translated into Arabic (e.g., complete intelligibility spatiality quality, hearing-screening)., Therefore, audiologists are advised either to use already existed validation tools in Arabic or to translate and culturally adapt Arabic versions of other tools in English. Such tools should be utilized in daily clinical work.
Limitations and future research
Although the present study provided important data about the current HAs practice in SA, not all practicing audiologists participated in the study. The questionnaire did not examine all HAs services provided by audiologists. The effect of variables, such as educational qualifications and work experience on the use of the best practice approach, was not investigated. This is an area that warrants further detailed study. Future research needs to identify the reasons for the poor training reported by audiologists and bridge that gap between the academic programs and clinical practice. There is still a pressing need to establish best practice guidelines for HAs fitting and other audiological services in SA.
| Conclusions|| |
Accurate HA fittings require appropriate verification and validation measurements to meet the patient's needs and confirm the value of the HA. This study showed important data about how audiologists verify and validate HAs fitting in SA. More than half of the participant audiologists either rarely or never used REMs and CBMs to verify HAs fitting mainly because of the lack of equipment, time, and proper training. Employers need to promote the best practices and eliminate difficulties to perform validation and verification measurements. Employers are advised to equip audiology workplaces by HAs verification systems, offer more time for HAs fitting cases, and support up-to-date training for audiologists. The limited number of standardized Arabic tools for validating HAs fitting allowed more than half of the participants to use unstructured general questions to measure the extent to which the HAs fitting goals have been achieved. Audiologists are encouraged either to utilize HAs fitting validation tools in Arabic or to translate and validate other tools in English.
The author would like to thank the SSSPA personnel for their assistance in distributing the questionnaire and all audiologists for their time and inputs.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| Appendix 1: Questionnaire|| |
(A) Demographic Information
- What is your gender?
- What is your age?
- What is your nationality?
- Other (please specify)
- In which region do you work?
- Other (please specify)
- What is your workplace?
- Governmental Hospital/Clinic
- Governmental Rehabilitation Center
- Private Practice
- Other (please specify)
- What is your highest attained degree? (Select all that apply)
- Doctor of Audiology (AuD)
- Doctor of Philosophy (PhD)
- Other (please specify)
- How long have you practiced in the field (Years)?
- What is the nature of your patients?
(B) Hearing Aids Fitting
- Are you fitting/dispensing hearing aids?
- No (Choose “Not Applicable” for questions 10–16)
- What are the type of hearing aids you fit? (Select all that apply)
- Behind the ear hearing aids
- Receiver in the canal/ear
- Custom hearing aids (ITE, completely-in-canal, invisible-in-the-canal, MIC, microphone-in-helix)
- Bilateral/ contralateral routing hearing aids (Bi/CROS)
- Other (please specify)
- Not Applicable
- How do you verify hearing aids fitting? (Select all that apply)
- Based on the patient's feedback
- Based on the functional gain measurements
- Based on the real ear measurements
- Based on coupler-based measurements
- Other (please specify)
- Not Applicable
- How often do you use real-ear measurements to verify and adjust the hearing aid?
- Not Applicable
- 13. How often do you use coupler-based measurements to verify and adjust the hearing aid?
- Not Applicable
- How do you validate hearing aids fitting? (Select all that apply)
- Abbreviated profile of hearing aid benefit (APHAB)
- Satisfaction with amplification in daily life
- Hearing handicap inventory for the Elderly/Adults
- Client Oriented Scale of Improvement
- Unstructured general questions
- Other (please specify)
- Not Applicable
- What formula do you use for fitting hearing aids? (Select all that apply)
- National Acoustic Laboratories- Non-Linear (NAL-NL1; NAL-NL2)
- Desired sensation level (DSL)
- Prescription of gain and maximum
- Other (please specify)
- Not applicable
- What are the reasons for not conducting real-ear/coupler-based measurements? (Select all that apply)
- Lack of Equipment
- Lack of time
- Space constraints
- Poor training
- Real-ear measurements/coupler-based measurements do not tell much
- Other (please specify)
- Not applicable
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[Figure 1], [Figure 2], [Figure 3]