2.4 Outcome Measures
After three months post-fitting, four main outcomes were administered:
(1) the time for wearing a hearing aid, (2) the hearing in noise test
(HINT)), (3) sound localization test, and (4) the Korean version of the
International Outcome Inventory for Hearing Aids (IOI-HA). The time for
wearing a hearing aid was investigated using IOI-HA as well as
data-logging. The HINT and sound localization were performed in unaided
and aided conditions. The HINT was performed with 50 recorded Korean
monosyllables were presented using presentation levels from 40 dB in
5-dB steps at a 1-meter distance in the sound-field while speech
spectrum noise was presented with a fixed intensity at SNR 0 dB.
Aided-unaided difference in speech discrimination score of more than 2%
was a criteria of meaningful difference. Sound localization test was
performed with spondee were presented at a fixed level of 50 dB at a
1-meter in azimuth of the front, right, and left sides in the
sound-field while the presented azimuth was randomly selected and the
speech was presented during 5 seconds with a silent interval of 5
seconds. The examinee answered the direction of a sound source. If the
examinee answered all three right, we did decide that he or she got a
sound localization. This study defined improved sound localization as
the case in which a test result was positive in aided condition
regardless of an unaided result.