Mobile phones may be used to assess hearing loss prevalence

The use of mobile phones is plausible for the measurement of hearing thresholds and may be helpful in large-scale, epidemiologic surveys, according to a recent study.

“Unsupervised self-tests require additional quality control based on the test duration and connection status of the headphones. Moreover, ambient noise and calibration method introduce additional bias,” researchers said. “Despite this, hearing thresholds measured by means of mobile devices were congruent with data reported in the literature.”

Researchers examined 733,716 tests collected from 236,716 devices across 212 countries. Almost all tests (99.3 percent) performed the hearing threshold measurement at the fundamental frequencies of 0.25, 0.5, 1, 2, 4, 6, and 8 kHz. After removing tests that were performed without connected headphones, 86.8 percent (n=637,169) remained.

Hearing loss, defined as a mean hearing threshold >25 dB in the better hear or 0.5–4 kHz, was most common for Pakistan (37.8 percent), Bangladesh (32.2 percent), and India (28.5 percent). The lowest prevalence rates were reported for Taiwan (9.6 percent), Finland (9.8 percent), and South Korea (10.2 percent). [J Med Internet Res 2020;22:e17238]

The global prevalence rate of hearing loss was 15.6 percent. Of the 212 countries assessed, 74 met the recommended sample size of 90 tests per country.

The effect of ambient noise was evaluated in 30,119 hearing tests conducted. The researchers found that ambient noise had an overall effect of 3.78 dB on hearing threshold, which corresponded to a 4.16-percent drop in country-specific prevalence rates.

Ambient noise peaked in Pakistan, Bangladesh, and India, which saw a 10.7-, 8.6-, and 6.2-percent decrease in the prevalence of hearing loss, respectively. Regardless, hearing loss remained most prevalent in these countries.

Notably, researchers saw that the device model was an important factor to consider. Hearing thresholds significantly differed among device models (p=0.01), which resulted directly from the biological calibration method. However, adjusting for the model changed the mean hearing threshold per country by only –0.07 dB.

“The required sample size was not reached in a significant number of African countries. In the poorest countries, the limiting factor is access to mobile devices and the internet,” the researchers said. “The same situation may also occur in countries with significant social stratification, contributing to the lower prevalences of hearing loss resulting from a lack of data from the poorer part of the population.”

Participants were recruited through the Hearing Test app, which was available for download on the Google Play store, for Android devices. Additionally, only users of devices for which the calibration coefficients had been previously determined were eligible for inclusion. All hearing tests were conducted using headphones bundled with the purchase of the mobile devices.

“This paper presents global country-specific prevalences of hearing loss based on self-tests carried out by Android users,” the researchers said. “Hearing tests on mobile devices may be a valid tool in epidemiological studies carried out on a large scale.”