WHO estimated in 2018 that there were 466 million people with disabling hearing loss, and over 80% of these resided in low-income and middle-income countries (LMICs).1 WHO has estimated that by 2050, [1] in 10 or 900 million people will experience disabling hearing loss unless substantial public health measures are implemented. Hearing loss is a very common sensory deficit in the elderly, and it is becoming a severe social and health problem. Especially in the elderly, hearing loss can impair the communication, thus significantly impacting everyday life, causing loneliness, isolation, dependence, and frustration, as well as communication disorders [2]. Hearing impairment and ear disease hearing loss can have significant consequences for the individual, and can be a substantial financial drain to society [3]. The presence and impact of disabling hearing loss is unequally distributed across the world, with the burden of hearing loss (both individual and societal) being greatest in low-resource countries, where access to education, medications, technology and interventions is limited [3]. And there is a huge  need for ear and hearing services, including surgical (eg, ear, nose and throat specialists (ENTs)) and rehabilitative services (eg, audiologists and speech therapists), to meet the increasing demand. Indeed, in order to achieve Universal Health Coverage (UHC) for the millions of people with hearing loss globally, equitable access to effective, high quality and affordable ear and hearing services are vital. However, access to these services is extremely low in LMICs [5], due to a dearth of human resources [5, 6]. The unmet need for hearing health care is high. Estimates of hearing aid use are that 67 to 86 percent of adults who might benefit from hearing aids do not use them [7]. At an individual level, hearing loss in childhood can cause oral language and communication impairment, leading to adverse effects in educational attainment and behaviour [8, 9]. In adults or the elderly, hearing loss is associated with depression, dementia and social isolation [10-12]. In order to address these challenges, Medtronic developed Shruti program in 2013 as an innovative cost-effective way to address the problem of ear disease and hearing loss, across the care continuum of screening, referral, and treatment. Shruti is the first technology-driven program that has integrated comprehensive ear care involving screening, diagnosis, treatment, and hearing rehabilitation of the individuals identified with ear problems [13]. The telemedicine device used in the program is called as ENT raview (Medtronic, Inc), a camera-enabled android phone integrated with an otoscope, audiometry screening, and a rechargeable, battery-operated light source .The digital camera of the smartphone captures tympanic membrane image and stores it in the memory of the smartphone, and a noise-isolating headset enables audiometry screening in semi-noisy environment. ENTraview utilizes smartphone technology and uses a store-and forward form of telemedicine through a cloud based data management platform. ENTraview allows community health workers to screen patient and generate a case with a unique identification number using an embedded app in the smartphone. The case comprises of demographic details, history of various symptoms, a picture of the tympanic membrane, and the provisional diagnosis made by the field worker. Based on the provisional diagnosis, community health workers counsel the identified patients for an in-clinic ENT and/or audiology examination and relevant investigations [13]. Patients with diminished hearing complaints also undergo hearing screening in the field through tele-audiology. In tele-audiology ENTraview device is used to administer air conduction threshold screening at 4 speech frequencies: 500 Hz, 1000 Hz, 2000 Hz, and 4000 Hz. The ENTraview kit also contains a calibrated headset which is enabled with circumaural stereo isolation headphones, with overall noise levels reduced by 25 db. A flow chart has been given below to explain the process of screening and further intervention [13]. We sought to determine the accuracy of the audiology assessments (done to determine how well a patient can hear) performed by the Shruti CHWs with the ENTraview as compared to the audiologist performed audiogram.    

To assess audiology accuracy. The study was approved by the institutional review board at Dr BAMRS Dr Hedgewar hospital. The goal of the audiology study was to estimate the accuracy of the ENTraview’s audiology functionality compared to a standard audiogram, and to conduct a sensitivity and specificity analysis on ENTraview’s audiology functionality in detecting patients with hearing loss and requiring a hearing aid. Due to which each component of the model of care is used, locational within the community, as well as within the patient continuum of care were used for the assessments. 

A prospective study was conducted at a partner site in Aurangabad, Maharashtra, India to compare the accuracy of the Shruti Audiology device to Standard Audiometry.  The first enrollment occurred in September 2019 and enrollment completed November 2019. During the study enrollment period, all individuals attending the audiology clinic who met the inclusion criteria and no exclusion criteria were offered participation in the study.  Recruitment and participation took place during their regularly scheduled audiogram appointments and was not based on presenting symptoms or results from previous audiometry. Enrollment continued until the predefined sample size of 50 patients consented and enrolled.  Fifty individuals, who met the following inclusion/exclusion criteria participated: age 18 or older, no pre-existing history of diagnosed hearing loss, both ears suitable for hearing assessment, no known cognitive disorder, at the discretion of the site audiologist, that would interfere with the hearing test procedures, willing and able to provide verbal consent to participate in Shruti audiology tests (one in a quiet environment defined by the site hospital’s audiogram sound booth and another in a noisy environment defined as the outpatient department of the hospital) and site performed audiology assessment, and no previous history of receiving an audiogram.  No incentives were offered to participants involved in the study and it was a free of charge screening for all the participants. 

Devices Utilized for the Assessment

Two different audiology assessment tools were utilized; the Shruti ENTraview audiology calibrated headset  and software application, and the site facility’s standard audiogram using their standard audiometry equipment. The devices were used to administer air conduction (AC) thresholds at four speech frequencies; 500Hz, 1000Hz, 2000Hz, and 4000Hz. The Shruti ENTraview audiology calibrated headset is enabled with  circumaural stereo isolation headphones, which reduces overall noise levels by 25 dB. Standard audiometry assessment utilizes GSI 61 Dual Channel Audiometer, calibrated to ISO389-1:1998 and TDH-50 headphone supra-aural headphones. Standard assessment of air conduction thresholds were estimated by an audiologist within a sound treated room (mean ambient noise level 37 dBA) according to ISO8253-1:2010. Prior to each assessment, the patient received thorough instructions on how to complete the test and was given the opportunity to ask any questions before the test began.  During the tests where the Shruti device was used, the patient was asked to signal by raising his/her hand when they heard a sound stimulus.  Similarly, during the site-performed audiogram, the patient was also asked to signal by raising his/her hand when they heard a sound stimulus. 

Study Design

The objective of this prospective study was to compare the accuracy of the Shruti audiology device to standard audiometry. Sensitivity and specificity analyses were conducted on the Shruti mobile audiology device in detecting patients with mild and moderate hearing loss. For each subject in the study, three audiology tests were performed on the subject; one utilizing the Shruti ENTraview audiology functionality in a noisy environment (the test was conducted in the outpatient department of the hospital), one utilizing the Shruti ENTraview audiology functionality in the site hospital’s audiogram sound booth, and one by a standard audiogram using the site’s sound booth testing room and standard audiometry equipment.   The Shruti ENTraview audiology tests in noisy and quiet environments were conducted by the Shruti community health worker.   The standard audiogram was performed by the site audiologist.  The standard audiogram and Shruti mobile device audiology tests were conducted independently without knowledge of the results by corresponding tests.   For each audiology test, the assessment data was collected twice, once for each ear. Air conduction thresholds (dB) were measured at 500 Hz, 1000 Hz, 2000 Hz, and 4000 Hz. Sensitivity was defined as the rate at which the Shruti mobile device accurately screen patient’s with significant hearing loss (PTA>40). Similarly, Specificity was defined as the rate at which Shruti ENTraview Audiology functionality could accurately identify patients with no significant hearing loss (PTA<40).

The primary objective is to evaluate the accuracy of Shruti mobile audiology device compared to a standard audiogram.  To assess the accuracy of the Shruti mobile device, an equivalence test was defined.  For each of the 3 audiology tests performed on a patient, a pure tone average was calculated for each patient’s ear.  Pure tone average (PTA) was defined as the average of the decibel thresholds at 500, 1000, 2000, and 4000 Hz tones. The difference between the Shruti tests and standard audiogram was calculated within a patient, and then the average difference was calculated across patients.  The average difference was assessed with an equivalence test, a two one-sided t-test (TOST), to test if the average difference is within an equivalence margin of ± 10 dB. 10dB was defined as the equivalence margin and is considered an agreeable level of accuracy.  Two one-sided t-tests were conducted; one to test if the difference was greater than -10 dB and the second to test if the difference was less than 10 dB. Each one-sided t-test was conducted with alpha-level equal to 0.05. Each ear was assumed to be independent. Additionally, a 95% confidence interval was calculated assuming a t-distribution.  If the p-value for both one-sided t-tests result in a p-value < 0.05, the objective was considered met, and the accuracy of the Shruti audiology device at measuring pure tone average within ± 10 dB was concluded.  The predefined analysis plan assumed the estimated difference between Shruti audiology device and standard deviation of difference equaled 21 dB, and therefore 50 patients and 100 ears would afford more than 90% power to test for an equivalence margin of ± 10 dB. Sensitivity and specificity analyses were also conducted.  Sensitivity was defined as the rate at which the Shruti mobile device accurately screen patient’s with significant hearing loss. Significant hearing loss was defined as a PTA > 40 dB. Of the patients assessed by the standard audiogram to have significant hearing loss (PTA > 40 dB), sensitivity was calculated as the number patients assessed by the Shruti mobile device with a PTA >40 dB divided by the number patients assessed by the standard audiogram with a PTA > 40 dB.  A corresponding 95% confidence interval was calculated using exact methods. Specificity was calculated as the number of patients assessed by the Shruti mobile device with a PTA ≤ 40 dB divided by the number patients assessed by the standard audiogram with a PTA ≤ 40 dB.  A corresponding 95% confidence interval was calculated using exact methods. Statistical analyses were performed using SAS software version 9.4 (SAS Institute, Cary, North Carolina)

A total of 50 patients participated in the study and the results from 100 ears were retained for analysis.  Patient characteristics are summarized in Table 1.a.

Table 1.a: Audiology Study Patient Demographics.

Patients on average were 57 years old and 34% female. On average, the Shruti ENTraview audiology functionality resulted in an air conduction threshold 6.2 ± 5.0 dB higher than the standard audiogram when the Shruti device assessment was conducted in a noisy environment. In a quiet environment, ENTraview  air conduction threshold was on average 3.9 ± 5.2 dB higher.  Both in the noisy and quiet environments, the ENTraview met the predefined study objective with ENTraview PTA within a 10 dB equivalence margin (both p<0.01, 1.b). The sensitivity and specificity results for screening the patient ear with significant hearing loss are displayed in Table 2 and Table 3.  

Table 1.b:  Audiology Accuracy Study Results.

Patients on average were 57 years old and 34% female. On average, the Shruti ENTraview audiology functionality resulted in an air conduction threshold 6.2 ± 5.0 dB higher than the standard audiogram when the Shruti device assessment was conducted in a noisy environment. In a quiet environment, ENTraview  air conduction threshold was on average 3.9 ± 5.2 dB higher.  Both in the noisy and quiet environments, the ENTraview met the predefined study objective with ENTraview PTA within a 10 dB equivalence margin (both p<0.01, 1.b). The sensitivity and specificity results for screening the patient ear with significant hearing loss are displayed in Table 2 and Table 3. 

Table 2:  Audiology Significant Hearing Loss Screening Accuracy (noisy).

In the noisy environment, the sensitivity rate for the Shruti ENTraview functionality to screen significant hearing loss was 100%. When a patient had hearing loss, the Shruti ENTraview was able to determine this 100% of the time. The corresponding specificity rate was 74%, or a 26% false positive rate (Table 2). Similarly in the quiet environment, sensitivity rate was also 100% and the specificity rate of the Shruti device improved with specificity equal to 81% and false positive rate of 19% (Table 3).

Table 3: Audiology Significant Hearing Loss Screening Accuracy (quiet).

In many developing countries hearing loss is measure problem due to lack of skilled professional, unavailability of audiological test and high cost of audiological equipment.  It is necessary to notice hearing loss as early as possible and to ensure this hearing should be check from time to time especially in individuals with higher risk factors for hearing loss.  In many recent publications have reported successful use of smart phone application in audiology.14Increase utility of internet based hearing test have suggested by some studies.15,16 Some studies have demonstrated  testing environment had a significant impact on the accuracy of results.16 In 2015 study by Paglialongaa, Tognola and Pinciroli showed that, in hearing health care, there is a distribution of available apps in five major categories;

• education & information (23%)
• Hearing testing (18%)
• Rehabilitation (24%)
• SOUND enhancement (28%) and
• assistive tools (7%).17 I

In a noisy environment, the sensitivity rate of the ENTraview audiology functionality to screen significant HL was 100%.  High sensitivity of this tool across various sound environments suggests its potential as a good screening tool. This, in addition, to the ease of use and minimal cost makes it viable to be used on a large volume of subjects with ease in a short period of time.  The study has been approved by Dr BAMRS Dr Hedgewar Hospital Ethics committee, Dr Hedgewar Hospital Aurangabad. With a high accuracy of audiology on-field assessment Shruti program will created an accurate way to increase access to screening/awareness, early diagnosis, and affordable treatment, for individuals with diagnosed ear disease as well as hearing loss, through their technology innovation and WHO guideline-based trained CHW workforce.

The burden of ear disease and hearing loss, within communities across India, is high and barriers exist, for patients and providers, across the continuum of care, including access to early screening and diagnosis. In order to address these issues, in 2013, an innovative ear care program, called Shruti, was launched in rural and urban areas across India to increase awareness, screening, diagnosis, and treatment for the underserved. Determining the accuracy of audiology assessments performed by the Shruti trained community-health workers (CHWs) using it’s screening device named “ENTraview” as compared to the audiologist performed audiogram was imperative and hence, this study was conducted. The goal of study was to estimate the accuracy of the ENTraview audiology functionality compared to a standard audiogram, and to conduct a sensitivity and specificity analysis on ENTraview audiology functionality in detecting patients with hearing loss and requiring a hearing aid. It was found that in noisy environment, the sensitivity rate for the Shruti ENTraview audiology functionality to screen significant hearing loss was 100% with specificity rate of 74%, or a 26% false positive rate; and in quiet environment, sensitivity rate was also 100% and the specificity rate of the Shruti device improved with specificity equal to 81% and false positive rate of 19%.With a high accuracy of audiology on-field assessment, it can be concluded that the Shruti program created an accurate way to increase access to screening/awareness, early diagnosis, and affordable treatment, for individuals with diagnosed ear disease as well as hearing loss, through their technology innovation and WHO guideline-based trained CHW workforce.

1. World Health Organization. Addressing the rising prevalence of hearing loss. Geneva: World Health Organization. 2018.
2. Ciorba A, Bianchini C, Pelucchi S, Pastore A. The impact of hearing loss on the quality of life of elderly adults. Clin Interv Aging. 2012; 7:159-163.
3. Graydon K, Waterworth C, Miller H, Gunasekera H. Global burden of hearing impairment and ear disease. The Journal of Laryngology & Otology .2019; 133: 18-25.
4. Bright T, Wallace S, Kuper H. A Systematic Review of Access to Rehabilitation for People with Disabilities in Low- and Middle-Income Countries. Int J Environ Res Public Health. 2018;15:2165.
5. Mulwafu W, Ensink R, Kuper H, Fagan J. Survey of ENT services in sub-Saharan Africa: little progress between 2009 and 2015. Glob Health Action. 2017; 10:1289736.
6. World Health Organization. Multi-Country assessment of national capacity to provide hearing care. 2013.
7. Bainbridge KE, Ramachandran V. Hearing aid use among older U.S. adults; the national health and nutrition examination survey, 2005-2006 and 2009-2010. Ear Hear. 2014; 35: 289-294.
8. Bennett KE, Haggard MP, Silva PA. Behaviour and developmental effects of otitis media with effusion into the teens Archives of Disease in Childhood 2001; 85:91-95.
9. Stevenson J, McCann D, Watkin P, Worsfold S, Kennedy C; Hearing Outcomes Study Team. The relationship between language development and behaviour problems in children with hearing loss. J Child Psychol Psychiatry. 2010; 51:77-83.
10. Falkenberg ES.Daily life consequences of hearing loss in the elderly. Disabil Rehabil. 2011; 33: 2179-2185.
11. The Lancet. Hearing loss: time for sound action. Lancet 2017; 390.
12. Cherko M , Hickson L , Bhutta M . Auditory deprivation and health in the   Maturitas 2016; 88:52-57.
13. Gupta N, Baghotia KS, Rabha M, Sachdeva S. Comprehensive Community Screening of Otological Patients by Trained Technicians Using a Telemedicine Device: An Efficient and Cost-Effective Way to Triage Patients With Ear Diseases. Ear Nose Throat J. 2020.
14. De Swanepoel W, Myburgh HC, Howe DM. Smartphone hearing screening with integrated quality control and data management. International Journal of Audiology 2014; 53: 841-849.
15. Bexelius C, Honeth L, Ekman A. Evaluation of an internet-based hearing test-comparison with established methods for detection of hearing loss. J Med Internet Res 2008; 10:e32.
16. Nast DR, Speer WS, Le Prell CG. Sound level measurements using smartphone "apps": useful or inaccurate? Noise Health 2014; 16:251-256.
17. Peer S, Fagan JJ. Hearing loss in the developing world: evaluating the iPhone mobile device as a screening tool. S Afr Med J 2015; 105:35-39.