Test instruments
An iPhone 4 mobile device (iOS 4.2) was used. The uHear app
(version 1.0) was downloaded from iTunes on to the device at
no cost. The application allows users to test their pure-tone airconduction
hearing sensitivity as well as speech in noise. For this
study, participants completed only the hearing sensitivity test, which
employs a 267 ms pulse duration, with a ‘10 dB down and 5 dB up’
approach. The time delay between tone presentations is randomised
to prevent anticipation, and the lowest threshold with two positive
responses of three excursions is recorded as the hearing sensitivity.
‘Earbud’ earphones that come standard with the device were
used, and the buds were cleaned with an alcohol swab before and
after every test in the presence of the participant. With reference to
calibration, a single iPhone was used to test all participants. The same
uHear application (version 1.0) was used for all participants tested.
Ambient noise levels in three test environments were measured at
regular intervals with the OMD G45 71-6229 Psio sound level meter,
providing an adequate measure of quality control. Sound levels for
the respective environment complied with the South African Bureau
of Standards requirements for all three environments.