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 Table of Contents  
ORIGINAL ARTICLE
Year : 2022  |  Volume : 36  |  Issue : 2  |  Page : 54-60

Validation of a low-cost, portable pure-tone audiometer


1 Department of Audiology, JSS Institute of Speech and Hearing, Dharwad, Karnataka, India
2 Department of Audiology, All India Institute of Speech and Hearing, Mysore, Karnataka, India

Date of Submission01-Aug-2022
Date of Decision03-Nov-2022
Date of Acceptance09-Nov-2022
Date of Web Publication10-Jan-2023

Correspondence Address:
Dr. Jijo Pottakkal Mathai
JSS Institute of Speech and Hearing, Kelageri, Dharwad - 580 007, Karnataka
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/jisha.jisha_16_22

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  Abstract 


Introduction: Around the world, there is an increasing demand for better hearing services. Access to hearing care involves the availability of accurate and calibrated audiometric apparatus. As audiometers are task-specific and expensive equipment, their portability is a common constraint. Hence, there is a need for developing low-cost, portable audiometers, so that the instrument can be quickly transported to remote regions and is conveniently accessible to multiple centers. Aim: The aim was to compare the air conduction (AC) and bone conduction (BC) thresholds obtained using newly developed Nautilus “KiVi” and a commercial, nonportable audiometer in both normal hearing and hearing-impaired individuals. Methods: The study included a total of 73 people, 52 having normal hearing sensitivity and 21 with hearing impairment. Results: It was found that among individuals with normal hearing except at 125 Hz, there was no significant difference in AC thresholds obtained using the Nautilus “KiVi” audiometer and a commercial, nonportable audiometer across frequencies. However, the BC thresholds obtained using the Nautilus “KiVi” audiometer was significantly better than that of a commercial, nonportable audiometer across frequencies. Among the individuals with hearing impairment, except at 8k Hz, there was no significant difference in AC thresholds obtained using the Nautilus “KiVi” audiometer and a commercial, nonportable audiometer. Conclusion: The Nautilus “KiVi”audiometers provide consistent results throughout a wide frequency range in those with normal hearing as well as with hearing impairment. The equipment is portable and easy to use. Hence, it can be used for diagnostic testing in schools, hospitals, remote villages, and industries.

Keywords: Commercial audiometer, Nautilus “KiVi”, pure-tone audiometry


How to cite this article:
Mathai JP, Spandita H L. Validation of a low-cost, portable pure-tone audiometer. J Indian Speech Language Hearing Assoc 2022;36:54-60

How to cite this URL:
Mathai JP, Spandita H L. Validation of a low-cost, portable pure-tone audiometer. J Indian Speech Language Hearing Assoc [serial online] 2022 [cited 2023 Feb 5];36:54-60. Available from: https://www.jisha.org/text.asp?2022/36/2/54/367504




  Introduction Top


Hearing loss, with its adverse personal and socioeconomic impacts, is a serious condition affecting people worldwide. According to the World Health Organization, approximately 466 million people suffer from hearing loss.[1] Recently, Verma et al.[2] reviewed studies that reported the prevalence of hearing loss in India from 1980 to 2020. They found that the prevalence of hearing loss ranged between 6% and 26.9%, and the prevalence of disabling hearing loss was between 4.5% and 18.3%. There was a higher prevalence of hearing impairment in the rural areas and among the elderly. Individuals who seem to be hearing impaired need extra effort to meet speech interpretation,[3] which can lead to psychosocial consequences,[4] fatigue, and mental distress,[5] and finally influencing the quality of life.[6] There is a growing demand for a better access to hearing services around the world.[7] Hearing evaluation using audiometers has become more popular as technology has advanced. Teixeira and Joubert stated that access to hearing care involves the availability of accurate and calibrated audiometric apparatus in both public and private facilities.[8] Audiometers are task-specific and expensive equipment; therefore, this is a typical constraint, and also their size makes portability difficult. Hence, there is a need for low-cost, portable audiometers, so that the instrument is easily accessible to various centers and can be easily transported to remote locations. Nautilus “KiVi,” a low-cost, portable, tablet-based diagnostic audiometer, developed by Nautilus Hearing Solutions Private Limited, Hubli, needs to be validated. Hence, the study aimed to compare the air conduction (AC) and bone conduction (BC) thresholds obtained using Nautilus “KiVi” and a commercial, nonportable audiometer in both normal and hearing-impaired individuals.


  Methods Top


A total of 73 individuals, 52 having normal hearing sensitivity and 21 with hearing impairment participated in the study. The age range of the normal hearing participants ranged between 18 and 25 years (mean age 19.82 years) and the hearing-impaired participants ranged between 9 and 80 years (mean age 38.61 years). All the participants were subjected to pure-tone audiometry using the modified Hughson-Westlake procedure.[9] The entire test procedures were carried out in a sound-treated two-room setup having ambient noise levels within the permissible limits of the ANSI Standard S3.1 (1999).[10] The participants included in the study underwent routine audiological evaluation using pure-tone audiometry, tympanometry, and otoacoustic emission (OAE). Audiological findings in normal hearing participants showed a pure-tone average of less than 15 dB HL. Normal middle ear functions with A-type tympanogram and presence of acoustic reflexes. The presence of OAE indicates normal outer hair cell functioning. The audiological test findings in individuals with hearing impairments are depicted in [Table 1].
Table 1: Demographic information and the audiological findings of the 21 individuals with hearing impairment

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Initially, AC thresholds were estimated for the octave and mid-octave frequencies from 125 Hz to 8 kHz and BC thresholds from 250 Hz to 4 kHz for the normal hearing sensitivity group. In the hearing impairment group, AC thresholds were estimated for the octave frequencies from 250 Hz to 8 kHz and BC thresholds from 250 Hz to 4 kHz. The above-mentioned data were collected from both the Nautilus “KiVi” Diagnostic audiometer that was electro-acoustically calibrated (Larson and Davis SLM type 824, pressure microphone 2575; artificial ear AEC 100) and a recently calibrated commercial, nonportable audiometer. [Table 2] depicts the audiometric threshold limits of both Nautilus “KiVi” audiometer and commercial, nonportable audiometer.
Table 2: Audiometric threshold limits in the Nautilus “KiVi” audiometer and a commercial, nonportable audiometer

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Calibration details and other technical specifications of Nautilus “KiVi” audiometer are given in [Appendix 1]a, [Appendix 1]b, [Appendix 1]c, [Appendix 1]d.



A standard group comparison design was used to compare the pure-tone thresholds obtained from the Nautilus “KiVi” audiometer and the commercial, nonportable audiometer.


  Results Top


Normal hearing individuals

The study aimed to compare AC thresholds of 52 normal hearing individuals obtained using a commercial, nonportable audiometer and Nautilus “KiVi”audiometer. Before this, AC thresholds of the right and left ears obtained using both the audiometers were compared using MANOVA, where the ear was the independent variable, and pure-tone thresholds across frequencies were the dependent variable. There was no significant difference in AC-hearing thresholds between the two ears in any of the frequencies ranging from 125 Hz to 8 kHz (P > 0.05). Hence, AC thresholds obtained from the two ears were clubbed for further analysis. Similar results were found using both the audiometers.

AC thresholds of 104 ears obtained using the two audiometers across frequencies were compared using MANOVA, where two different audiometers were the independent variable, and pure-tone thresholds across frequencies were the dependent variable. The results revealed that among the normal hearing ears, there was no significant difference in AC hearing thresholds between the two audiometers in any of the frequencies ranging from 250 Hz to 8 kHz (P > 0.05). However, at 125 Hz, AC hearing thresholds obtained using the commercial audiometer were significantly better than Nautilus “KiVi” audiometer (P < 0.05). The mean and SD of AC thresholds obtained using a commercial, nonportable audiometer and Nautilus “KiVi” audiometer in individuals with normal hearing are given in [Table 3].
Table 3: The mean and standard deviation of air conduction thresholds obtained using a commercial, nonportable audiometer and Nautilus “KiVi” audiometer in individuals with normal hearing

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BC thresholds of 52 individuals with normal hearing obtained using a commercial, nonportable audiometer and Nautilus “KiVi” audiometer across frequencies were compared. A MANOVA was performed where the audiometers were the independent variable, and pure-tone thresholds across frequencies were the dependent variable. In the normal hearing ears, BC hearing thresholds obtained using the Nautilus “KiVi” audiometer were significantly better than a commercial audiometer across frequencies ranging from 250 Hz to 4 kHz (P < 0.05).

Hearing-impaired individuals

AC thresholds obtained using a commercial, nonportable audiometer and Nautilus “KiVi” audiometers were compared among 41 ears having hearing impairment across frequencies. One of the ears having normal hearing sensitivity was removed. A MANOVA was performed where audiometers were the independent variable, and pure-tone thresholds across frequencies were the dependent variable. Among the 41 ears having hearing loss, there was no significant difference in AC hearing thresholds between the two audiometers in any of the frequencies ranging from 250 Hz to 4 kHz (P > 0.05). However, at 8 kHz, AC hearing thresholds obtained using the Nautilus “KiVi” audiometer were significantly better than a commercial audiometer (P < 0.05). The mean and SD of AC thresholds obtained using a commercial, nonportable audiometer and Nautilus “KiVi” audiometer in individuals with hearing impairment are given in [Table 4]. There was no significant difference in BC hearing thresholds between the two audiometers in any of the frequencies ranging from 250 Hz to 4 kHz (P > 0.05).
Table 4: The mean and standard deviation of air conduction thresholds obtained using a commercial, nonportable audiometer and Nautilus “KiVi” audiometer in individuals with hearing impairment

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  Discussion Top


The results of the present study revealed that both AC and BC pure-tone thresholds obtained using the Nautilus “KiVi”audiometer are reliable. It was found that AC thresholds obtained using the Nautilus “KiVi” audiometer across frequencies were not significantly different from that of a commercial, nonportable audiometer except at 125 Hz. At 125 Hz, although there was a mean difference of 2.9 dB, it is not very relevant: as 125 Hz is not being used clinically while testing. However, at other frequencies, the average mean difference in hearing thresholds between the two audiometers was <2 dB. Similarly, Jacobs et al. reported an average threshold difference of 1.1 dB across frequencies from 500 Hz to 8 kHz in nine individuals with normal hearing while developing and standardizing an audiometer.[11] The maximum difference of 7.1 dB was observed at 16 kHz between the developed and commercial audiometers. Similarly, Colsman et al. reported hearing threshold differences ranging from 0.48 dB to 4.1 dB HL between the tabled-based audiometers and commercial audiometers (AM MAICO MA25).[12]

However, BC thresholds obtained using Nautilus “KiVi” audiometer across frequencies were significantly better than a commercial, nonportable audiometer. It was noted that the average BC thresholds obtained using the former audiometer were 5 dB better than the latter across frequencies. This could be due to the difference in BC calibration procedure followed for the two audiometers. Nautilus “KiVi” audiometer was calibrated at various levels from -5 dB to 70 dB [Appendix 1c], whereas a commercial, nonportable audiometer was often calibrated at 70 dB only. Hence, better hearing thresholds were observed for BC at lower intensities while using the former equipment.

Among those with hearing loss, no significant difference was observed in AC and BC thresholds obtained using the Nautilus “KiVi” audiometer and a commercial, nonportable audiometer except at 8 kHz. This could be due to the maximum limit set for AC thresholds at 8 kHz. In the Nautilus “KiVi” audiometer, the maximum limit at 8 kHz was 80 dB HL, whereas, in the commercial, nonportable audiometer, it was 95 dB HL. There was no significant difference in BC thresholds between the two audiometers across frequencies. The average difference in hearing thresholds between the two audiometers across frequencies was 1 dB for both AC and BC thresholds. Similarly, Jacobs et al. reported a threshold difference of 0.22 dB in one subject having hearing loss.[11] Thoidis et al. compared pure-tone thresholds obtained using a tablet-based audiometer and a commercial audiometer (GSI-61) among subjects having all degrees of hearing loss. They found that both AC and BC thresholds have an absolute threshold difference of 3.3 dB.[13]

Similar findings in air conduction audiometry have been reported in other research, with a good test–retest reliability and no statistically significant differences.[14],[15],[16],[17],[18] According to Saliba et al. and Foulad et al., 85.2% and 80.1% of hearing thresholds determined by a professional application differed by up to 5 dB from the commercial audiometer.[19],[20] The KUDUwave portable automated audiometer was verified in studies by Swanepoel and Biagio and Brennan-Jones et al., which found that 92% and 86% of cases were within 10 dB, respectively.[21],[22] It is clear that AC and BC thresholds obtained using the Nautilus “KiVi” were not significantly different from the commercial audiometer. Moreover, the threshold difference between the Nautilus “KiVi” audiometer and commercial audiometer was much smaller than similar reported studies.


  Conclusion Top


It can be concluded that the low-cost Nautilus “KiVi” audiometers are simple and easy to handle. The instrument gives reliable results across a broad range of frequencies in individuals with normal hearing as well as hearing impairment. Hence, the audiometer can be used for diagnostic, pure-tone hearing evaluation in the clinical population. Moreover, the low-cost equipment can be immediately used for hearing assessment in industries, schools, and other rural facilities.

Acknowledgment

The authors would like to thank the JSS Institute of Speech and Hearing, Dharwad, where the study was carried out. Sincere thanks to Nautilus Hearing Solutions, Hubli, for their technical support.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
New WHO-ITU Standard Aims to Prevent Hearing Loss among 1.1 Billion Young People. World Health Organization; 2019. Available from: https://www.who.int/news/item/12-02-2019-new-who-itu-standard-aims-to-prevent-hearing-loss-among-1.1-billion-young-people. [Last accessed on 2022 Jul 27].  Back to cited text no. 1
    
2.
Verma RR, Konkimalla A, Thakar A, Sikka K, Singh AC, Khanna T. Prevalence of hearing loss in India. Natl Med J India 2021;34:216-22.  Back to cited text no. 2
    
3.
Rönnberg J, Lunner T, Zekveld A, Sörqvist P, Danielsson H, Lyxell B, et al. The Ease of Language Understanding (ELU) model: Theoretical, empirical, and clinical advances. Front Syst Neurosci 2013;7:31.  Back to cited text no. 3
    
4.
Hornsby BW. The effects of hearing aid use on listening effort and mental fatigue associated with sustained speech processing demands. Ear Hear 2013;34:523-34.  Back to cited text no. 4
    
5.
Kramer SE, Kapteyn TS, Festen JM, Kuik DJ. Assessing aspects of auditory handicap by means of pupil dilatation. Audiology 1997;36:155-64.  Back to cited text no. 5
    
6.
Strawbridge WJ, Wallhagen MI, Shema SJ, Kaplan GA. Negative consequences of hearing impairment in old age: A longitudinal analysis. Gerontologist 2000;40:320-6.  Back to cited text no. 6
    
7.
Swanepoel de W, Clark JL, Koekemoer D, Hall JW 3rd, Krumm M, Ferrari DV, et al. Telehealth in audiology: The need and potential to reach underserved communities. Int J Audiol 2010;49:195-202.  Back to cited text no. 7
    
8.
Teixeira L, Joubert K. Availability of audiological equipment and protocols for paediatric assessment and hearing aid fitting in Gauteng, South Africa. S Afr J Commun Disord 2014;61:1-8. [doi: 10.4102/sajcd.v61i1.58].  Back to cited text no. 8
    
9.
Carhart R, Jerger J. Preferred method for clinical determination of pure-tone thresholds. J Speech Hear Disord 1959;24:330-45.  Back to cited text no. 9
    
10.
ANSI S3.1-1999 (R2003). Maximum Permissible Ambient Noise Levels for Audiometric Test Rooms. New York, NY, USA: American National Standards Institute; 1999.  Back to cited text no. 10
    
11.
Jacobs PG, Silaski G, Wilmington D, Gordon S, Helt W, McMillan G, et al. Development and evaluation of a portable audiometer for high-frequency screening of hearing loss from ototoxicity in homes/clinics. IEEE Trans Biomed Eng 2012;59:3097-103.  Back to cited text no. 11
    
12.
Colsman A, Supp GG, Neumann J, Schneider TR. Evaluation of accuracy and reliability of a mobile screening audiometer in normal hearing adults. Front Psychol 2020;11:744.  Back to cited text no. 12
    
13.
Thoidis I, Vrysis L, Markou K, Papanikolaou G. Development and evaluation of a tablet-based diagnostic audiometer. Int J Audiol 2019;58:476-83.  Back to cited text no. 13
    
14.
Swanepoel de W, Myburgh HC, Howe DM, Mahomed F, Eikelboom RH. Smartphone hearing screening with integrated quality control and data management. Int J Audiol 2014;53:841-9.  Back to cited text no. 14
    
15.
Samelli AG, Rabelo CM, Sanches SGG, Aquino CP, Gonzaga D. Tablet-based hearing screening test. Telemed J E Health 2017;23:747-52.  Back to cited text no. 15
    
16.
Yeung J, Javidnia H, Heley S, Beauregard Y, Champagne S, Bromwich M. The new age of play audiometry: Prospective validation testing of an iPad-based play audiometer. J Otolaryngol Head Neck Surg 2013;42:21.  Back to cited text no. 16
    
17.
Yeung JC, Heley S, Beauregard Y, Champagne S, Bromwich MA. Self-administered hearing loss screening using an interactive, tablet play audiometer with ear bud headphones. Int J Pediatr Otorhinolaryngol 2015;79:1248-52.  Back to cited text no. 17
    
18.
Corry M, Sanders M, Searchfield GD. The accuracy and reliability of an app-based audiometer using consumer headphones: Pure tone audiometry in a normal hearing group. Int J Audiol 2017;56:706-10.  Back to cited text no. 18
    
19.
Saliba J, Al-Reefi M, Carriere JS, Verma N, Provencal C, Rappaport JM. Accuracy of mobile-based audiometry in the evaluation of hearing loss in quiet and noisy environments. Otolaryngol Head Neck Surg 2017;156:706-11.  Back to cited text no. 19
    
20.
Foulad A, Bui P, Djalilian H. Automated audiometry using apple iOS-based application technology. Otolaryngol Head Neck Surg 2013;149:700-6.  Back to cited text no. 20
    
21.
Swanepoel de W, Biagio L. Validity of diagnostic computer-based air and forehead bone conduction audiometry. J Occup Environ Hyg 2011;8:210-4.  Back to cited text no. 21
    
22.
Brennan-Jones CG, Eikelboom RH, Swanepoel de W, Friedland PL, Atlas MD. Clinical validation of automated audiometry with continuous noise-monitoring in a clinically heterogeneous population outside a sound-treated environment. Int J Audiol 2016;55:507-13.  Back to cited text no. 22
    



 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4]



 

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