Comparison of temporal fine structure sensitivity and concurrent vowel perception between children with and without reading disability

Background: Children with reading disabilities (RD) exhibit difficulty in perceiving speech in background noise due to poor auditory stream segregation. There is a dearth of literature on measures of temporal fine structure sensitivity (TFS) and concurrent vowel perception abilities to assess auditory stream segregation in children with reading disabilities. Hence the present study compared temporal fine structure sensitivity (TFS) and concurrent vowel perception abilities between children with and without reading deficits. Method: The present research consisted of a total number of 30 participants, 15 children with reading disabilities (RD) and fifteen typically developing (TD) children within the age range of 7-14 years and were designated as Group 1 and Group 2 respectively. Both groups were matched for age, grade, and classroom curricular instructions. The groups were evaluated for TFS and concurrent vowel perception abilities and the performance was compared using independent ‘t’ test and repeated measure ANOVA respectively. Results: Results revealed that the children with RD performed significantly (p < 0.001) poorer than TD children on both TFS and concurrent vowel identification task. On concurrent vowel identification tasks, there was no significant interaction found between reading ability and F0 difference suggesting that the trend was similar in both the groups. Conclusion: The study concludes that the children with RD show poor temporal fine structure sensitivity and concurrent vowel identification scores compared to age and grade matched TD children owing to poor auditory stream segregation in children with RD.

Nonlinear dynamics in auditory cortical activity reveal the neural basis of perceptual warping in speech categorization

Surrounding context influences speech listening, resulting in dynamic shifts to category percepts. To examine its neural basis, event-related potentials (ERPs) were recorded during vowel identification with continua presented in random, forward, and backward orders to induce perceptual nonlinearities. Behaviorally, sequential order shifted listeners' categorical boundary vs. random delivery revealing perceptual warping (biasing) of the heard phonetic category dependent on recent stimulus history. ERPs revealed later (~300 ms) activity localized to superior temporal and middle/inferior frontal gyri that predicted listeners' hysteresis magnitudes. Findings demonstrate that top-down, stimulus history effects on speech categorization are governed by interactions between frontotemporal brain regions.

Clinical Speech fMRI in Children and Adolescents

Purpose In patients with drug-resistant focal epilepsy, surgical resection is often the only treatment option to achieve long-term seizure control. Prior to brain surgery involving potential language areas, identification of hemispheric language dominance is crucial. Our group developed and validated a functional magnetic resonance imaging (fMRI) battery of four pediatric language tasks. The present study aimed at optimizing fMRI data acquisition and analysis using these tasks. Methods We retrospectively analyzed speech fMRI examinations of 114 neuropediatric patients (age range 5.8–17.8 years) who were examined prior to possible epilepsy surgery. In order to evaluate hemispheric language dominance, 1–4 language tasks (vowel identification task VIT, word-chain task WCT, beep-story task BST, synonym task SYT) were measured. Results Language dominance was classified using fMRI activation in the 13 validly lateralizing ROIs (VLR) in frontal, temporal and parietal lobes and cerebellum of the recent validation study from our group: 47/114 patients were classified as left-dominant, 34/114 as bilateral and 6/114 as right-dominant. In an attempt to enlarge the set of VLR, we then compared for each task agreement of these ROI activations with the classified language dominance. We found four additional task-specific ROIs showing concordant activation and activation in ≥ 10 sessions, which we termed validly lateralizing (VLRnew). The new VLRs were: for VIT the temporal language area and for SYT the middle frontal gyrus, the intraparietal sulcus and cerebellum. Finally, in order to find the optimal sequence of measuring the different tasks, we analyzed the success rates of single tasks and all possible task combinations. The sequence 1) VIT 2) WCT 3) BST 4) SYT was identified as the optimal sequence, yielding the highest chance to obtain reliable results even when the fMRI examination has to be stopped, e.g., due to lack of cooperation. Conclusion Our suggested task order together with the enlarged set of VLRnew may contribute to optimize pediatric speech fMRI in a clinical setting.

Development of Mandarin Chinese Vowel Perception in Young Children With Normal Hearing and Cochlear Implants

Purpose Depicting the development pattern of vowel perception for children with normal hearing (NH) and cochlear implants (CIs) would be useful for clinicians and school teachers to monitor children's auditory rehabilitation. The study was to investigate the development of Mandarin Chinese vowel perception for Mandarin Chinese native–speaking children with the ages of 4–6 years. Method Vowel identification of children with NH and CIs were tested. All children with CIs received CIs before the age of 4 years. In a picture identification task with Mandarin Chinese speech stimuli, listeners identified the target consonant–vowel word among two to four contrastive words that differed only in vowels. Each target word represented a concrete object and was spoken by a young female native Mandarin Chinese talker. The target words included 16 monophthongs, 22 diphthongs, and nine triphthongs. Results Children with NH showed significantly better identification of monophthongs and diphthongs than children with CIs at the age of 6 years, whereas the two groups had comparable performance at age of 4 and 5 years. Children with NH significantly outperformed children with CIs for triphthong identification across all three age groups. For children with NH, a rapid development of perception of all three types of vowels occurred between age 4 and 5 years with a rapid development only for monophthong perception between age 5 and 6 years. For children with CIs, a rapid development of both diphthong and triphthong perception occurred between 4 and 5 years old, but not monophthong, with no significant development between 5 and 6 years old for all three types of vowels. Overall, Mandarin-speaking children with NH achieved their ceiling performance in vowel perception before or at the age of 6 years, whereas children with CIs may need more time to reach the typical level of their peers with NH. Conclusions The development of Mandarin vowel perception for Mandarin-native children differed between preschool-age children with NH and CIs, likely due to the deficits of spectral processing for children with CIs. The results would be a supplement to the development of speech recognition in Mandarin-native children with NH and CIs.

Aging Effect on Mandarin Chinese Vowel and Tone Identification in Six-Talker Babble

Purpose The purpose of this study was to measure Mandarin Chinese vowel-plus-tone identification in quiet and noise for younger and older listeners. Method Two types of noise served as the masker, namely, six-talker babble and babble-modulated noise, at two signal-to-noise ratios (SNRs) of −4 and −8 dB. Fourteen listeners from both age groups were recruited, and three sets of data analyses were conducted: the identification of vowel plus tone, the identification of vowel, and the identification of tone. Results Younger listeners outperformed older listeners in all listening conditions, whereas the younger–older listener difference became greater in noise than in quiet, indicating a more detrimental effect of noise for older listeners than for younger listeners. In addition, vowel identification showed slightly better scores than tone identification in noise, suggesting that noise appeared to affect tone perception more negatively than vowel perception in Mandarin Chinese. At −4 dB SNR, there was a significantly greater amount of informational masking (IM) and a greater amount of energetic masking (EM) for older listeners than for younger listeners. At −8 dB SNR, there was a greater amount of EM for older listeners than for younger listeners but with no group difference in the amount of IM. Conclusion These results suggest that older listeners received a more negative impact of noise for Mandarin Chinese phonemic and tone recognition and had a larger amount of IM or EM from competing speech noise than younger listeners, depending on the SNR.

Second Language Experience Facilitates Sentence Recognition in Temporally-Modulated Noise for Non-native Listeners

Non-native listeners deal with adverse listening conditions in their daily life much harder than native listeners. However, previous work in our laboratories found that native Chinese listeners with native English exposure may improve the use of temporal fluctuations of noise for English vowel identification. The purpose of this study was to investigate whether Chinese listeners can generalize the use of temporal cues for the English sentence recognition in noise. Institute of Electrical and Electronics Engineers (IEEE) sentence recognition in quiet condition, stationary noise, and temporally-modulated noise were measured for native American English listeners (EN), native Chinese listeners in the United States (CNU), and native Chinese listeners in China (CNC). Results showed that in general, EN listeners outperformed the two groups of CN listeners in quiet and noise, while CNU listeners had better scores of sentence recognition than CNC listeners. Moreover, the native English exposure helped CNU listeners use high-level linguistic cues more effectively and take more advantage of temporal fluctuations of noise to process English sentence in severely degraded listening conditions [i.e., the signal-to-noise ratio (SNR) of −12 dB] than CNC listeners. These results suggest a significant effect of language experience on the auditory processing of both speech and noise.

Assessing merged status with Pillai scores based on dynamic formant contours

When Pillai scores are used to study vowel mergers, formants are typically sampled from the midpoint. This study compares alternative methods for calculating Pillai scores: methods that incorporate dynamic spectral information. Eighteen speakers produced 20 tokens of Hodd and hawed. Formants were sampled at 20–35–50–65–80% duration. Seven Pillai scores were calculated, each based on a different subset of those samples with temporal pooling: (i) onsets, (ii) heads, (iii) midpoints, (iv) onsets + offsets, (v) heads + tails, (vi) onsets + midpoints + offsets, and (vii) all five. Subjects also completed a vowel identification task, and the rate of identifying one low-back vowel as the other was calculated. The results of the identification task were regressed on each Pillai score separately to identify the one with the highest correlation, through model selection. Dynamic formant contours performed better than static formant values, with midpoint sampling performing worst of all. Directions are discussed for basic research on Pillai scores in phonetics.