50 for sentences. Table 1. Model fit of proportion of plural /s/ detected in words with age group,. SMRT threshold, and better ear aided SII as predictors. Table 2.
Spectral resolution and speech recognition in noise for children with hearing loss Benjamin Kirby, Ph.D.1, Jenna Browning, B.S.2, Marc Brennan, Ph.D.1, Meredith Spratford, Au.D.1, Ryan McCreery, Ph.D.1 Boys Town National Research Hospital, Omaha, NE 1. & The University of North Carolina at Chapel Hill, Department of Allied Health Sciences2
INTRODUCTION Better spectral resolution has been associated with higher speech recognition in noise in adults with hearing loss who use hearing aids and adults with cochlear implants. Children have different etiologies and configurations of hearing loss than adult listeners in previous studies. However, the role of signal audibility and age on the relationship between spectral resolution and speech recognition has not been reported. The goal of this study was to evaluate the effect of aided audibility and spectral resolution on speech recognition in noise for a group of children with sensorineural hearing loss and a group of adults with hearing loss.
HYPOTHESES Higher age (contrasting adults and children), better aided audibility and the ability to detect more ripples per octave in a spectral ripple discrimination task were predicted to be associated with better sentence, word, and plural recognition in noise for children and adults with hearing loss.
METHOD Listeners
Listeners included 15 children (ages 6-16) and 17 adults (ages 19-71) with mild to severe sensorineural hearing loss (Figure 1).
children participating in the study (Storkel & Hoover, 2010). Three lists of words and three lists of sentences were balanced by initial phoneme across the lists. Half of the words in each word list contained the plural morpheme /s/ and half of the embedded nouns in each sentence list contained the plural morpheme /s/. Gaussian noise frequency shaped to the long-term average spectrum of the speech stimuli was added to prevent potential ceiling effects and adapted to obtain 50% on the PI function.
Table 1. Model fit of proportion of plural /s/ detected in words with age group, SMRT threshold, and better ear aided SII as predictors.
Spectral ripple discrimination task Spectral-ripple discrimination was measured for broadband noise stimuli using the spectral-temporally modulated ripple test (SMRT) developed by Aronoff & Landsberger (2013). The SMRT is an adaptive procedure in which the ripple density of the target stimulus is varied to estimate the 50% discrimination threshold. Testing consisted of a three-interval, forced-choice task in which two of the intervals contained a reference stimulus of 20 ripples per octave (RPO). The beginning RPO was 0.5 RPO and the step size was 0.2 RPO using a 1-up/1-down stepping rule. Ten reversals were obtained and threshold was calculated using the last six reversals. Each participant completed two runs and the final threshold was determined by averaging the two threshold estimates. Stimuli were presented via a JBL Bi-Amplified Studio Monitor loudspeaker at 45 degrees azimuth.
Table 4. Bivariate correlations of listener age with ripple threshold and better ear SII in the child participants; partial correlation of age and ripple threshold holding SII constant.
DISCUSSION
Table 2. Model fit of proportion of SNR-50 for words, SMRT threshold, and better ear aided SII as predictors.
• Better spectral ripple discrimination ability was associated with more accurate detection of plural /s/ in noise in children and adults who use hearing aids. • Greater aided SII was associated with better sentence recognition ability in noise in children and adults who use hearing aids. • Greater listener age was associated with better spectral ripple discrimination ability in children who use hearing aids after controlling for differences in audibility.
Statistical methods
CLINICAL IMPLICATIONS
Generalized linear model (GLM) analyses were completed with speech perception performance as dependent variables and age group (child vs. adult), better ear aided SII for a 65 dB SPL signal, and aided SMRT as predictor variables. Additional analysis of partial correlation of listener age with SMRT, controlled for SII, was also completed with the child data.
Table 3. Model fit of proportion of SNR-50 for sentences, SMRT threshold, and better ear aided SII as predictors.
Measures of spectral ripple discrimination can be completed in children who wear hearing aids. This non-linguistic measure may provide additional information about supra-threshold listening ability in children that is not accounted for by objective measures of aided audibility.
ACKNOWLEDGEMENTS
RESULTS
This work was supported by NIH/NIDCD R01 DC013591, P30 DC-4662, P20 GM109023, and the Andrew Hetzel Research Fund. Jenna Browning completed the Short-Term Research Training Program supported by NIH/NIDCD T35DC008757. The authors wish to thank Skip Kennedy for assistance with poster preparation.
REFERENCES Fig. 1. Average audiometric thresholds for right ear (O) and left ear (X) for adults (left panel) and children (right panel). The range of thresholds for each age group is plotted as the hatched area.
• ANSI, A. (1997). S3. 5-1997, Methods for the calculation of the speech intelligibility index. New York: American National Standards Institute. • Aronoff & Landsberger (2013). The Journal of the Acoustical Society of America, 134(2), EL217-EL222. • Hodson et al. (2014) American Journal of Audiology, 23, 3, 351-8. • Storkel & Hoover (2010). Behavior Research Methods, 42, 2, 497-506.
Amplification Participants completed all tasks using their own personal hearing aids. Realear measures of aided audibility (SII; ANSI S3.5-1997) were completed for each participant.
Figure 3. Ripple threshold vs. listener age for child participants (N=15). Better ear aided SII (BSII65) is scaled by color shading. Performance tended to improve with greater listener age and audibility.
Speech recognition task Stimuli for speech recognition were monosyllabic words with and without the plural morpheme /s/ and singular and plural nouns embedded in low context sentences (Hodson, Spratford, Brennan, Leibold, & McCreery, 2014). Monosyllabic words were within the average lexicon for the youngest
Figure 2. Scatterplot matrix of listener age, ripple threshold, better ear aided SII, proportion of plural /s/ detected in words, SNR-50 for words, and SNR50 for sentences.
