Background: While testing suprathreshold word recognition at multiple levels is considered best
practice, studies on practice patterns do not suggest that this is common practice.
Audiologists often test at a presentation level intended to maximize recognition scores,
but methods for selecting this level are not well established for a wide range of
hearing losses.
Purpose: To determine the presentation level methods that resulted in maximum suprathreshold
phoneme-recognition scores while avoiding loudness discomfort.
Research Design: Performance-intensity functions were obtained for 40 participants with sensorineural
hearing loss using the Computer-Assisted Speech Perception Assessment. Participants
had either gradually sloping (mild, moderate, moderately severe/severe) or steeply
sloping losses. Performance-intensity functions were obtained at presentation levels
ranging from 10 dB above the SRT to 5 dB below the UCL (uncomfortable level). In addition,
categorical loudness ratings were obtained across a range of intensities using speech
stimuli. Scores obtained at UCL – 5 dB (maximum level below loudness discomfort) were
compared to four alternative presentation-level methods. The alternative presentation-level
methods included sensation level (SL; 2 kHz reference, SRT reference), a fixed-level
(95 dB SPL) method, and the most comfortable loudness level (MCL).
For the SL methods, scores used in the analysis were selected separately for the SRT
and 2 kHz references based on several criteria. The general goal was to choose levels
that represented asymptotic performance while avoiding loudness discomfort. The selection
of SLs varied across the range of hearing losses.
Results: Scores obtained using the different presentation-level methods were compared to scores
obtained using UCL – 5 dB. For the mild hearing loss group, the mean phoneme scores
were similar for all presentation levels. For the moderately severe/severe group,
the highest mean score was obtained using UCL − 5 dB. For the moderate and steeply
sloping groups, the mean scores obtained using 2 kHz SL were equivalent to UCL − 5
dB, whereas scores obtained using the SRT SL were significantly lower than those obtained
using UCL − 5 dB. The mean scores corresponding to MCL and 95 dB SPL were significantly
lower than scores for UCL − 5 dB for the moderate and the moderately severe/severe
group.
Conclusions: For participants with mild to moderate gradually sloping losses and for those with
steeply sloping losses, the UCL – 5 dB and the 2 kHz SL methods resulted in the highest
scores without exceeding listeners' UCLs. For participants with moderately severe/severe
losses, the UCL − 5 dB method resulted in the highest phoneme recognition scores.
Key Words
Hearing loss - presentation level - speech audiometry - speech discrimination - speech
recognition testing
