Abstract
Purpose This project was undertaken to develop automated tests of speech recognition, including
speech-recognition threshold (SRT) and word-recognition test, using forced-choice
responses and computerized scoring of responses. Specific aims were (1) to develop
an automated method for measuring SRT for spondaic words that produces scores that
are in close agreement with average pure-tone thresholds and (2) to develop an automated
test of word recognition that distinguishes listeners with normal hearing from those
with sensorineural hearing loss and which informs the hearing aid evaluation process.
Method An automated SRT protocol was designed to converge on the lowest level at which the
listener responds correctly to two out of two spondees presented monaurally. A word-recognition
test was conducted with monosyllabic words (female speaker) presented monaurally at
a fixed level. For each word, there were three rhyming foils, displayed on a touchscreen
with the test word. The listeners touched the word they thought they heard. Participants
were young listeners with normal hearing and listeners with sensorineural hearing
loss. Words were also presented with nonrhyming foils and in an open-set paradigm.
The open-set responses were scored by a graduate student research assistant.
Results The SRT results agreed closely with the pure-tone average (PTA) obtained by automated
audiometry. The agreement was similar to results obtained with the conventional SRT
scoring method. Word-recognition scores were highest for the closed-set, nonrhyming
lists and lowest for open-set responses. For the hearing loss participants, the scores
varied widely. There was a moderate correlation between word-recognition scores and
pure-tone thresholds which increased as more high frequencies were brought into the
PTA. Based on the findings of this study, a clinical protocol was designed that determines
if a listener's performance was in the normal range and if the listener benefited
from increasing the level of the stimuli.
Conclusion SRTs obtained using the automated procedure are comparable to the results obtained
by the conventional clinical method that is in common use. The automated closed-set
word-recognition test results show clear differentiation between scores for the normal
and hearing loss groups. These procedures provide clinical test results that are not
dependent on the availability of an audiologist to perform the tests.
Keywords
forced-choice - speech recognition - speech-recognition threshold
