Objective We examined how cognitive and linguistic skills affect speech recognition in noise for children with normal hearing. Children with better working memory and language abilities were expected to have better speech recognition in noise than peers with poorer skills in these domains. Design As part of a prospective, cross-sectional study, children with normal hearing completed speech recognition in noise for three types of stimuli: (1) monosyllabic words, (2) syntactically correct but semantically anomalous sentences and (3) semantically and syntactically anomalous word sequences. Measures of vocabulary, syntax and working memory were used to predict individual differences in speech recognition in noise. Study sample Ninety-six children with normal hearing, who were between 5 and 12 years of age. Results Higher working memory was associated with better speech recognition in noise for all three stimulus types. Higher vocabulary abilities were associated with better recognition in noise for sentences and word sequences, but not for words. Conclusions Working memory and language both influence children’s speech recognition in noise, but the relationships vary across types of stimuli. These findings suggest that clinical assessment of speech recognition is likely to reflect underlying cognitive and linguistic abilities, in addition to a child’s auditory skills, consistent with the Ease of Language Understanding model.

Children with HAs show deficits in sensitivity to phonological structure but appear to take advantage of vocabulary skills to support speech perception in the same way as children with NH. Further investigation is needed to understand the causes of the gap that exists between the overall speech perception abilities of children with HAs and children with NH.

Children's performance on psychophysical tasks improves with age. The relationship of spectro-temporal modulation detection to age, particularly in children who are hard of hearing, is not well-established. In this study, children with normal hearing (N = 22) and with sensorineural hearing loss (N = 15) completed measures of spectro-temporal modulation detection. Measures of aided audibility were completed in the children who are hard of hearing. Pearson product-moment correlations were completed with listener age and aided audibility as parameters. Spectro-temporal modulation detection performance increased with listener age and with greater aided audibility.

Objectives To determine whether an “optimal” DPOAE protocol including (1) optimal stimulus levels and primary-frequency ratios for each f2, (2) simultaneously measuring 2f2-f1 and 2f1-f2 distortion products, (3) controlling source contribution, (4) implementing improved calibration techniques, (5) accounting for the influence of middle-ear reflectance, and (6) applying multivariate analyses to DPOAE data results in improved accuracy in differentiating between normal-hearing and hearing-impaired ears, compared to a standard clinical protocol. Design Data were collected for f2 frequencies ranging from 0.75 to 8 kHz in 28 normal-hearing and 78 hearing-impaired subjects. The protocol included a control condition incorporating standard stimulus levels and primary-frequency ratios calibrated with a standard sound pressure level (SPL) method and three experimental conditions using optimized stimuli calibrated with an alternative forward pressure level (FPL) method. The experimental conditions differed with respect to the level of the reflection-source suppressor tone, and included conditions referred to as the null-suppressor (i.e., no suppressor tone presented), low-level suppressor (i.e., suppressor tone presented at 58 dB SPL), and high-level suppressor (i.e., suppressor tone presented at 68 dB SPL) conditions. The area under receiver operating characteristic (AROC) curves and sensitivities for fixed specificities (and vice versa) were estimated to evaluate test performance in each condition. Results AROC analyses indicated (1) improved test performance in all conditions using multivariate analyses, (2) improved performance in the null-suppressor and low-suppressor experimental conditions compared to the control condition, and (3) poorer performance below 4 kHz with the high-level suppressor. As expected from AROC, sensitivities for fixed specificities and specificities for fixed sensitivities were highest for the null-suppressor and low-suppressor conditions and lowest for standard clinical procedures. The influence of 2f2-f1 and reflectance on test performance was negligible. Conclusions Predictions of auditory status based on DPOAE measurements in clinical protocols may be improved by the inclusion of (1) optimized stimuli, (2) alternative calibration techniques, (3) low-level suppressors, and (4) multivariate analyses.

Objective Nucleus Hybrid CI users hear low-frequency sounds via acoustic stimulation and high frequency sounds via electrical stimulation. This within-subject study compares three different methods of coordinating programming of the acoustic and electrical components of the Hybrid device. Speech perception and cortical auditory evoked potentials (CAEP) were used to assess differences in outcome. The goals of this study were to determine (1) if the evoked potential measures could predict which programming strategy resulted either in better outcome on the speech perception task or was preferred by the listener, and (2) whether CAEPs could be used to predict which subjects benefitted most from having access to the electrical signal provided by the Hybrid implant. Design CAEPs were recorded from 10 Nucleus Hybrid CI users. Study participants were tested using three different experimental MAPs that differed in terms of how much overlap there was between the range of frequencies processed by the acoustic component of the Hybrid device and range of frequencies processed by the electrical component. The study design included allowing participants to acclimatize for a period of up to 4 weeks with each experimental program prior to speech perception and evoked potential testing. Performance using the experimental MAPs was assessed using both a closed-set consonant recognition task and an adaptive test that measured the signal to noise ratio that resulted in 50% correct identification of a set of 12 spondees presented in background noise (SNR-50). Long-duration, synthetic vowels were used to record both the cortical P1-N1-P2 “onset” response and the auditory “change” or ACC response. Correlations between the evoked potential measures and performance on the speech perception tasks are reported. Results Differences in performance using the three programming strategies were not large. Peak-to-peak amplitude of the AAC response was not found to be sensitive enough to accurately predict the programming strategy that resulted in the best performance on either measure of speech perception. All 10 Hybrid CI users had residual low frequency acoustic hearing. For all 10 subjects, allowing them to use both the acoustic and electrical signals provided by the implant improved performance on the consonant recognition task. For most subjects, it also resulted in slightly larger cortical change responses. However, the impact that listening mode had on the cortical change responses was small and again, the correlation between the evoked potential and speech perception results was not significant. Conclusions CAEPs can be successfully measured from Hybrid CI users. The responses that are recorded are similar to those recorded from normal hearing listeners. The goal of this study was to see if CAEPs might play a role either in identifying the experimental program that resulted in best performance on a consonant recognition task or documenting benefit from use of the electrical signal provided by the Hybrid CI. At least for the stimuli...

Objectives Nonlinear frequency compression is a signal processing technique used to increase the audibility of high frequency speech sounds for hearing aid users with sloping, high frequency hearing loss. However, excessive compression ratios may reduce spectral contrast between sounds and negatively impact speech perception. This is of particular concern in infants and young children who may not be able to provide feedback about frequency compression settings. This study explores use of an objective cortical auditory evoked potential that is sensitive to changes in spectral contrast, the auditory change complex (ACC), in the verification of frequency compression parameters. Design ACC responses were recorded from adult listeners to a spectral ripple contrast stimulus that was processed using a range of frequency compression ratios (1:1, 1.5:1, 2:1, 3:1, and 4:1). Vowel identification, consonant identification, speech recognition in noise (QuickSIN), and behavioral ripple discrimination thresholds were also measured under identical frequency compression conditions. In Experiment 1, these tasks were completed in 10 adults with normal hearing. In Experiment 2, these same tasks were repeated in 10 adults with sloping, high frequency hearing loss. Results Repeated measures ANOVAs were completed for each task and each group with frequency compression ratio as the within-subjects factor. Increasing the compression ratio did not affect vowel identification for the normal hearing group but did cause a significant decrease in vowel identification for the hearing-impaired listeners. Increases in compression ratio were associated with significant decrements in ACC amplitudes, consonant identification scores, ripple discrimination thresholds, and speech perception in noise scores for both groups of listeners. Conclusions The ACC response, like speech and non-speech perceptual measures, is sensitive to frequency compression ratio. Further work is needed to establish optimal stimulus and recording parameters for the clinical application of this measure in the verification of hearing aid frequency compression settings.

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SHORT SUMMARY Bilateral cochlear implantation has motivated efforts to ensure that sounds presented at equal levels to each ear are perceived as equally loud. Psychophysical loudness balancing is not always practical, especially with pediatric users. Electrophysiological potentials -- electrically evoked auditory brain stem response (EABR) and electrically evoked compound action potential (ECAP) measures -- may provide a means of approximating loudness balance. It was hypothesized that stimuli evoking equal amplitude neural responses would be more closely matched in loudness than stimuli with equal current levels. No significant differences in loudness discrepancy across ears were found for ECAP, EABR or matched current levels.