Abstract:
There are approximately 1.7 billion smartphone downloads of health surveillance
applications, which have become vital in modern day living (Economist, 2016). The
smartphone Digits-in-Noise (DIN) test was developed with South African English digits
and was released and marketed in 2016 as a smartphone application allowing for an
accessible hearing screening solution (Potgieter et al., 2016). Typically, the test is
completed with coupling to headphones/earphones. However, due to several limitations,
such as the lack of availability or inability to utilise headphones/earphones, performing
tests with earphones/headphones may not always be possible. Therefore, this study
aimed to determine if the results obtained via earphones would be comparable to those
obtained in the sound field via various transducers.
The study employed a cross-sectional, quasi-experimental research design. Fifty
normal hearing participants (bilateral pure tone thresholds 0.5 – 8kHz ≤ 15dB HL)
between the ages of 18 to 25 years (mean 20; SD ±1.93) were recruited. The study
consisted of two test sessions over two days and used a repeated measure design
where the conditions were counterbalanced using a Latin square setup. The first test
session compared the SRTs of the smartphone DIN test across Samsung Fame Lite
earphones, two smartphone speakers and two external loudspeakers in a sound booth.
Test session two determined the test-retest reliability of the above conditions.
Results of this study indicated that there was no significant difference (p > 0.05) between
the SRTs across the four different loudspeakers and earphones. It also demonstrated
that the test-retest differences across the various loudspeakers was not significant (p >
0.05). Findings indicate that test-retest results in the sound field using various
transducers is reliable.
This study demonstrated that a smartphone version of the DIN test can be utilised in the
sound field using various transducers with equivalent results compared to an earphone
condition. Therefore, the smartphone DIN test can be implemented in any practice
which has access to a controlled testing environment for screening and rehabilitation
purposes. A limitation of the current study is that the smartphone DIN test is designed
for users to utilise the application in a home environment where ambient noise and
reverberation is not controlled. Therefore, a future research priority is to conduct the
testing in a home environment. Based on the findings of this study, it is expected that the smartphone DIN test performed through the sound field will be a promising tool in a
home environment if the noise and reverberation is low.
