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The Promise of Smartphone Apps for Hearing Tests

Hogan, Cynthia PhD

doi: 10.1097/01.HJ.0000491112.87757.ff
Journal Club

Dr. Hogan is a consultant in the Division of Audiology and director of the Hearing Aid Program at the Mayo Clinic.

With the global reach of the internet, telemedicine has made affordable and quality health care more accessible to people who previously may not have had access. Such access improvement also spurred an increase in the development and testing of hearing care that can be done either remotely or using readily available devices. Some of the developments in remote care delivery have been incorporated into applications (apps) for mobile devices such as smartphones, tablets, and other mobile devices. Cell phone use has increased significantly in the recent years, with about 65 to 89 percent prevalence in seven sub-Saharan African nations and smartphone ownership ranging from 15 to 65 percent among cell phone users in countries studied (Pew Research Center, 2014 According to the China Internet Network Information Centre report in 2015, there are 668 million internet users in China, and most of these use smartphone (CNNIC, 2015

In a study by Paglialonga et al., a keyword search for mobile device apps was done using terms that were related to hearing, audiology, speech, language, tinnitus and other related words. They were able to find 203 apps that were then classified into four categories: screening and assessment, intervention and rehabilitation, education and information, and assistive tools (Paglialonga. Am J Audiol 2015;24[3]:293 More than half of the apps (52%) were categorized as for intervention and rehabilitation, 17 percent were for screening and assessment, 23 percent for education and information, and 7 percent were identified as assistive tools. Approximately half of the apps were available for free.

Audiologists often begin their health care service with a hearing evaluation. One app that has been developed for this purpose is called hearScreen. The screening can be self-administered or done by a tester. This app has been validated using an inexpensive smartphone and headphones. Specificity and sensitivity using hearScreen have been found to be equivalent to conventional testing for school hearing screening programs. The app monitors environmental noise in the test area and collects data for record-keeping purposes. Sandstrom et al. published the results of a study that evaluated hearScreen for accuracy, reliability, and test duration (Int J Audiol 2016;55[4]:232 Ninety-four adult subjects, aged 18-88 years, participated in the study. Sixty-four of the subjects had their hearing tested in a sound booth by an audiologist using a GSI 61 audiometer, supra-aural TDH 40 headphones, and a modified Hughson-Westlake threshold technique. Thirty subjects were evaluated in a primary care clinic in a non-booth environment using a KUDUwave audiometer and insert earphones with circumaural earcups and monitors to track ambient noise during testing. The primary care clinic testing was computer-automated using a modified Hughson-Westlake technique as well. hearScreen testing was completed on all subjects using a Samsung Galaxy S3 cell phone with supra-aural Sennheiser HD202 II headphones in the environment in which their hearing was tested (booth or non-booth). Thresholds were obtained at 500, 1000, 2000, 4000 and 8000 Hz, and retested at 1000 Hz on the smartphone app for reliability.

For the purposes of comparison, thresholds </=15 dB were considered normal. Results showed that more thresholds were found to be within the normal range in the booth compared with normal thresholds found in the primary care environment. In the booth, 63.4 percent of the thresholds identified as within normal range by conventional testing were also identified as within normal limits using the smartphone app. In the primary care environment, only 13.7 percent of thresholds identified as normal with conventional testing were also identified as normal using the smartphone app. Further investigation of those thresholds that were >15 dB showed that the agreement between thresholds obtained by conventional testing and smartphone app in the booth was statistically different at all octave frequencies except 4000 Hz. The agreement between thresholds obtained by conventional testing and smartphone thresholds in the primary care environment (non-booth) was only statistically different at 4000 Hz. Although the threshold differences between methods was significant at some frequencies, the mean differences between thresholds obtained via conventional and smartphone methods at all frequencies except 500 Hz in the booth, in both the booth and non-booth conditions, were within +/-5.0 dB. The average differences across frequencies were within +/-10 dB in 80.6 percent of the measures made in the booth and 92.9 percent in the primary care setting. Threshold retesting at 1000 Hz showed that the measures were reliable using the smartphone app in both the booth and outside of the booth. The test duration was 296 seconds in the booth and 355 seconds in the primary-care environment, which was statistically significant.

The results of this study suggested that the hearScreen smartphone app can be used to accurately measure hearing thresholds in a booth and outside of a booth in a primary care setting, within the clinically acceptable test-retest variability. Thresholds obtained using the app were found to be reliable with repeated measures of thresholds at 1000 Hz in the booth and outside of the booth. The average test took 59 seconds longer in the primary care environment than in the booth.

Early access to hearing evaluation can result in early treatment and rehabilitation. By offering diagnostic options using readily available technology such as smartphones audiologists will have a greater impact in providing immediate hearing health care services.

Sandstrom, J, Swanepoel, D, Myburgh, H, Laurent, C. Smartphone threshold audiometry in underserved primary health-care contexts. Int J Audiol. 2016;55(4):232-8

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