Study limitations
More participants with varying degrees
of hearing loss would possibly yield
more accurate positive and negative
predictive values, thereby rendering the
testing more accurate. Environmental
noise may have been a cause for poor
results at the lower frequencies. Testing
can possibly be improved by using
background noise eliminators. Inset
earphones are theoretically recommended
as an effective way to reduce ambient
noise. Being placed within the external
ear canal, they can provide 30 - 40 dB
attenuation of ambient noise.[27] In our
study, inaccuracy can be related to
insertion depth; ‘earbud’ earphones sit just
beyond the concha at the entrance to the
external ear canal, which could explain the
poor low-frequency outcomes. In future,
testing that incorporates inset earphones
cupped by circumaural ear covers with
integrated ambient noise level monitoring
that eliminates or adjusts testing to
accommodate background noise could be
done. Although this would be ideal, it does
counter the intention to screen using a
device with its standard hardware. A single
iPhone device was used for this study; to
avoid problems relating to inter-device
reliability, every iPhone may have to be
calibrated.