Development of Basic Auditory Discrimination in Preschool Children

Perception of voice cues in school-age children with hearing aids

The just-noticeable differences (JNDs) of the voice cues of voice pitch (F0) and vocal-tract length (VTL) were measured in school-aged children with bilateral hearing aids and children and adults with normal hearing. The JNDs were larger for hearing-aided than normal-hearing children up to the age of 12 for F0 and into adulthood for all ages for VTL. Age was a significant factor for both groups for F0 JNDs, but only for the hearing-aided group for VTL JNDs. Age of maturation was later for F0 than VTL. Individual JNDs of the two groups largely overlapped for F0, but little for VTL. Hearing thresholds (unaided or aided, 500-400 Hz, overlapping with mid-range speech frequencies) did not correlate with the JNDs. However, extended low-frequency hearing thresholds (unaided, 125-250 Hz, overlapping with voice F0 ranges) correlated with the F0 JNDs. Hence, age and hearing status differentially interact with F0 and VTL perception, and VTL perception seems challenging for hearing-aided children. On the other hand, even children with profound hearing loss could do the task, indicating a hearing aid benefit for voice perception. Given the significant age effect and that for F0 the hearing-aided children seem to be catching up with age-typical development, voice cue perception may continue developing in hearing-aided children.

Speech-in-speech recognition in preschoolers

OBJECTIVE

The purpose of this study was to 1) characterise word recognition in a speech masker for preschoolers tested using closed-set, forced-choice procedures and 2) better understand the stimulus and listener factors affecting performance.

DESIGN

Speech recognition thresholds (SRTs) in a two-talker masker were evaluated using a picture-pointing response with two sets of disyllabic target words. ChEgSS words were previously developed for children ≥5 years of age, and simple words were developed for preschoolers. Familiarisation ensured accurate identification of target words before testing.

STUDY SAMPLE

Participants were 3- and 4-year olds (n = 21) and young adults (n = 10) with normal hearing.

RESULTS

Preschoolers and adults had significantly lower SRTs for the simple words than the ChEgSS words, and lower SRTs for early-acquired than later-acquired ChEgSS words. For both word sets, SRTs were approximately 11-dB higher for preschoolers than adults, and child age was associated with SRTs. Preschoolers' receptive vocabulary size predicted performance for ChEgSS words but not simple words.

CONCLUSIONS

Preschoolers were more susceptible to speech-in-speech masking than adults, with a similar child-adult difference for the ChEgSS and simple words. Effects of receptive vocabulary in preschoolers' recognition of ChEgSS words indicate that vocabulary size is an important consideration, even when using closed-set methods.

Evaluation of Temporal Processing Abilities in Competing Noise

Temporal processing is critical to a wide variety of everyday listening tasks, including speech perception. Although the importance of signal to noise ratio (SNR) is well documented in speech perception experiments, it is less explored in temporal processing experiments. The present study examined the effect of SNR on temporal processing abilities using Gap Detection Threshold (GDT) in children and adults. The study included a total of 45 subjects, where in, 25 children (Group-1) and 20 adults (Group-2) with pure-tone thresholds ranging from 0 to 25 dB HL at frequency range 250-8000 Hz. The GDT was measured at presentation level 50 dBSL. All the measurements were performed in 5 different conditions: 'Quiet', ' + 10 dB SNR', ' + 5 dB SNR', ' + 0 dB SNR' and ' - 5 dB SNR'. Gap Detection Thresholds are significantly higher from + 10 to - 5 dB SNR when compared to quiet condition in young-adults and all sub-groups of children, whereas at + 10 dB SNR, thresholds were not significantly different from quiet condition in young-adults and all sub-groups of children except for sub-group A of children, and were significantly different for all the five conditions. It was revealed that, as the signal to noise ratio (SNR) was decreased from + 10 dB SNR to 0 dB SNR there was a significant increase in Gap Detection Thresholds. There was a significant increase in Gap Detection Thresholds from + 10 dB SNR to - 5 dB SNR in both children and adults. The results also suggest that the performance on temporal processing task in the presence of background noise achieves young-adult like pattern by the age of 10-11 years. Background noise affect temporal processing in both children and young-adults. Background noise impairs temporal processing in children more than the adults, which could be because of poor temporal resolving abilities in children.

Musical Training Enhances Categorical Perception of Speech in Preschoolers: Training Duration and Musical Program Matter

PURPOSE

Previous research has indicated the beneficial effects of musical training on speech perception in children. However, little has been known about whether musical training exerts transfer effects on fine-grained perception of linguistic pitch and time information. This study aimed to investigate the effects of different musical training programs and training duration on preschoolers' categorical perception (CP) of lexical tones and voice onset time (VOT) in Mandarin Chinese, which utilize pitch and time changes, respectively, to convey phonemic contrasts.

METHOD

Sixty-one Mandarin-speaking children aged 4 years were randomly assigned to pitch-based musical training (carillon group), rhythm-based musical training (drum group), or handcraft learning (control group). Children completed the tests designed to assess their musical abilities, CP of lexical tones and VOT, IQ, and working memory at three time-points. Repeated-measures analyses of variance were conducted to evaluate the training-related effects in various tasks. Correlation analyses were used to infer the relationships between musical abilities and CP performance of speech.

RESULTS

The carillon group demonstrated advantages over the drum and control groups in music pitch processing and CP of lexical tones; besides, the drum group performed better in the music time processing and CP of VOT than the control group. Moreover, positive correlations were found between musical gains and improvements on CP of speech.

CONCLUSIONS

These results provide evidence that transfer effects occur in CP of lexical tones and VOT in preschoolers. Our findings highlight the selectivity of musical advantages driven by different components of training programs and suggest that long-term musical training could be a means of early speech rehabilitation in children with communication disorders.

Developmental Changes in the Perception of Vocal Loudness and Voice Quality in 3- to 6-Year-Old Children

PURPOSE

The study's primary aim was to investigate developmental changes in the perception of vocal loudness and voice quality in children 3-6 years of age. A second aim was to evaluate a testing procedure-the intermodal preferential looking paradigm (IPLP)-for the study of voice perception in young children.

METHOD

Participants were categorized in two age groups: 3- to 4-year-olds and 5- to 6-year-olds. Children were tested remotely via a Zoom appointment and completed two perceptual tasks: (a) voice discrimination and (b) voice identification. Each task consisted of two tests: a vocal loudness test and a voice quality test.

RESULTS

Children in the 5- to 6-year-old group were significantly more accurate than children in the 3- to 4-year-old group in discriminating and identifying differences between voices for both loudness and voice quality. The IPLP, used in the identification task, was found to successfully detect differences between the age groups for overall accuracy and for most of the sublevels of vocal loudness and voice quality.

CONCLUSIONS

Results suggest that children's ability to discriminate and identify differences in vocal loudness and voice quality improves with age. Findings also support the use of the IPLP as a useful tool to study voice perception in young children.

Preschoolers Have Difficulty Discriminating Novel Minimal-Pair Words

PURPOSE

The primary aim was to assess whether children have difficulty distinguishing similar-sounding novel words. The secondary aim was to assess what task characteristics might hinder or facilitate perceptual discrimination.

METHOD

Three within-subjects experiments tested ninety-nine 3- to 5-year-old children total. Experiment 1 presented two cartoon characters each saying a novel word. Children were asked to report whether they said the same word or different words. Words were identical (e.g., deev/deev), were dissimilar (deev/vush), differed in onset consonant voicing (deev/teev), or differed in vowel tenseness (deev/div). Experiment 2 added accuracy feedback after each trial to remind children of task instructions. Experiment 3 interspersed many "same" trials containing a repeating standard word to assess the role of bottom-up stimulus support on difference detection.

RESULTS

The d' scores were highest for dissimilar words, next highest on different-vowel pairs, and lowest on different-consonant pairs. Performance was better with repeated standard stimuli (Experiment 3) than without (Experiment 1). Benefits for repeated task instructions (Experiment 2) were marginal. Exploratory analyses comparing these results to findings in a word-learning study using the same stimuli suggest an imperfect match to how easily children can learn similar-sounding words.

CONCLUSIONS

Overall, similar-sounding novel words are challenging for children to discriminate perceptually, although discrimination scores exceeded chance for all levels of similarity. Clinically speaking, same/different tests may be less sensitive to sound discrimination than change/no-change tests.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.20151848.

Interactions between auditory statistics processing and visual experience emerge only in late development

The auditory system relies on local and global representations to discriminate sounds. This study investigated whether vision influences the development and functioning of these fundamental sound computations. We employed a computational approach to control statistical properties embedded in sounds and tested samples of sighted controls (SC) and congenitally (CB) and late-onset (LB) blind individuals in two experiments. In experiment 1, performance relied on local features analysis; in experiment 2, performance benefited from computing global representations. In both experiments, SC and CB performance remarkably overlapped. Conversely, LB performed systematically worse than the other groups when relying on local features, with no alterations on global representations. Results suggest that auditory computations tested here develop independently from vision. The efficiency of local auditory processing can be hampered in case sight becomes unavailable later in life, supporting the existence of an audiovisual interplay for the processing of auditory details, which emerges only in late development.

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Computational and deprivation models can be combined to assess sensory plasticity

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Basic auditory computations develop independently from early visual input

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Late-onset sight loss can hamper the efficiency of local auditory processing

Development of Masked Speech Detection Thresholds in 2- to 15-year-old Children: Speech-Shaped Noise and Two-Talker Speech Maskers

OBJECTIVES

On the basis of the data from school-aged children, there is consistent evidence that there is a prolonged course of auditory development for perceiving speech embedded in competing background sounds. Furthermore, age-related differences are prolonged and pronounced for a two-talker speech masker compared to a speech-shaped noise masker. However, little is known about the course of development during the toddler and preschool years because it is difficult to collect reliable behavioral data from this age range. The goal of this study was to extend our lower age limit to include toddlers and preschoolers to characterize the developmental trajectory for masked speech detection thresholds across childhood.

DESIGN

Participants were 2- to 15-year-old children (n = 67) and adults (n = 17), all with normal hearing. Thresholds (71%) were measured for detecting a two-syllable word embedded in one of two maskers: speech-shaped noise or two-talker speech. The masker was presented at 55 dB SPL throughout testing. Stimuli were presented to the left ear via a lightweight headphone. Data were collected using an observer-based testing method in which the participant's behavior was judged by an experimenter using a two-interval, two-alternative testing paradigm. The participant's response to the stimulus was shaped by training him/her to perform a conditioned play-based response to the sound. For children, receptive vocabulary and working memory were measured. Data were fitted with a linear regression model to establish the course of development for each masker condition. Appropriateness of the test method was also evaluated by determining if there were age-related differences in training data, inter-rater reliability, or slope or upper asymptote estimates from pooled psychometric functions across different age groups.

RESULTS

Child and adult speech detection thresholds were poorer in the two-talker masker than in the speech-shaped noise masker, but different developmental trajectories were seen for the two masker conditions. For the speech-shaped noise masker, threshold improved by about 5 dB across the age span tested, with adult-like performance being reached around 10 years of age. For the two-talker masker condition, thresholds improved by about 7 dB between 2.5 and 15 years. However, the linear fit for this condition failed to achieve adult-like performance because of limited data from teenagers. No significant age-related differences were seen in training data, probe hit rate, or inter-rater reliability. Furthermore, slope and upper asymptote estimates from pooled psychometric functions were similar across different child age groups.

CONCLUSIONS

Different developmental patterns were seen across the two maskers, with more pronounced child-adult differences and prolonged immaturity during childhood for the two-talker masker relative to the speech-shaped noise masker. Our data do not support the idea that there is rapid improvement of masked speech detection thresholds between 2.5 and 5 years of age. This study also highlights that our observer-based method can be used to collect reliable behavioral data from toddlers and preschoolers-a time period where we know little about auditory development.

Development of binaural temporal fine structure sensitivity in children

The highest frequency for which the temporal fine structure (TFS) of a sinewave can be compared across ears varies between listeners with an upper limit of about 1400 Hz for young normal-hearing adults (YNHA). In this study, binaural TFS sensitivity was investigated for 63 typically developing children, aged 5 years, 6 months to 9 years, 4 months using the temporal fine structure-adaptive frequency (TFS-AF) test of Füllgrabe, Harland, Sęk, and Moore [Int. J. Audiol. 56, 926-935 (2017)]. The test assesses the highest frequency at which an interaural phase difference (IPD) of ϕ° can be distinguished from an IPD of 0°. The values of ϕ were 30° and 180°. The starting frequency was 200 Hz. The thresholds for the children were significantly lower (worse) than the thresholds reported by Füllgrabe, Harland, Sęk, and Moore [Int. J. Audiol. 56, 926-935 (2017)] for YNHA. For both values of ϕ, the median age at which children performed above chance level was significantly higher (p < 0.001) than for those who performed at chance. For the subgroup of 40 children who performed above chance for ϕ = 180°, the linear regression analyses showed that the thresholds for ϕ = 180° increased (improved) significantly with increasing age (p < 0.001) with adult-like thresholds predicted to be reached at 10 years, 2 months of age. The implications for spatial release from masking are discussed.

The Influence of the Psychophysical Assessment Paradigm on Pitch Discrimination for Adults (and a Pilot Sample of Children)

Pitch discrimination ability has been of research interest due to its potential relationship to language and literacy. However, assessment protocols for pitch discrimination have varied widely. Prior studies with both children and adults have produced conflicting performance findings across different pitch discrimination research paradigms, though they have consistently shown that discrimination accuracy is based on the psychophysical assessment method applied. In the present study, we examined pitch discrimination performance among convenience samples of 19 adult women and ten female children across six different adaptive psychophysical measurement conditions. We found pitch discrimination performance in both groups to be impacted by the measurement paradigm such that, while adults exhibited significantly better discrimination thresholds than did children, the pattern of performance across the six conditions was similar for both the adults and the children.

Children With Normal Hearing Are Efficient Users of Fundamental Frequency and Vocal Tract Length Cues for Voice Discrimination

BACKGROUND

The ability to discriminate between talkers assists listeners in understanding speech in a multitalker environment. This ability has been shown to be influenced by sensory processing of vocal acoustic cues, such as fundamental frequency (F0) and formant frequencies that reflect the listener's vocal tract length (VTL), and by cognitive processes, such as attention and memory. It is, therefore, suggested that children who exhibit immature sensory and/or cognitive processing will demonstrate poor voice discrimination (VD) compared with young adults. Moreover, greater difficulties in VD may be associated with spectral degradation as in children with cochlear implants.

OBJECTIVES

The aim of this study was as follows: (1) to assess the use of F0 cues, VTL cues, and the combination of both cues for VD in normal-hearing (NH) school-age children and to compare their performance with that of NH adults; (2) to assess the influence of spectral degradation by means of vocoded speech on the use of F0 and VTL cues for VD in NH children; and (3) to assess the contribution of attention, working memory, and nonverbal reasoning to performance.

DESIGN

Forty-one children, 8 to 11 years of age, were tested with nonvocoded stimuli. Twenty-one of them were also tested with eight-channel, noise-vocoded stimuli. Twenty-one young adults (18 to 35 years) were tested for comparison. A three-interval, three-alternative forced-choice paradigm with an adaptive tracking procedure was used to estimate the difference limens (DLs) for VD when F0, VTL, and F0 + VTL were manipulated separately. Auditory memory, visual attention, and nonverbal reasoning were assessed for all participants.

RESULTS

(a) Children' F0 and VTL discrimination abilities were comparable to those of adults, suggesting that most school-age children utilize both cues effectively for VD. (b) Children's VD was associated with trail making test scores that assessed visual attention abilities and speed of processing, possibly reflecting their need to recruit cognitive resources for the task. (c) Best DLs were achieved for the combined (F0 + VTL) manipulation for both children and adults, suggesting that children at this age are already capable of integrating spectral and temporal cues. (d) Both children and adults found the VTL manipulations more beneficial for VD compared with the F0 manipulations, suggesting that formant frequencies are more reliable for identifying a specific speaker than F0. (e) Poorer DLs were achieved with the vocoded stimuli, though the children maintained similar thresholds and pattern of performance among manipulations as the adults.

CONCLUSIONS

The present study is the first to assess the contribution of F0, VTL, and the combined F0 + VTL to the discrimination of speakers in school-age children. The findings support the notion that many NH school-age children have effective spectral and temporal coding mechanisms that allow sufficient VD, even in the presence of spectrally degraded information. These results may challenge the notion that immature sensory processing underlies poor listening abilities in children, further implying that other processing mechanisms contribute to their difficulties to understand speech in a multitalker environment. These outcomes may also provide insight into VD processes of children under listening conditions that are similar to cochlear implant users.

Auditory neurophysiological development in early childhood: A growth curve modeling approach

OBJECTIVE

During early childhood, the development of communication skills, such as language and speech perception, relies in part on auditory system maturation. Because auditory behavioral tests engage cognition, mapping auditory maturation in the absence of cognitive influence remains a challenge. Furthermore, longitudinal investigations that capture auditory maturation within and between individuals in this age group are scarce. The goal of this study is to longitudinally measure auditory system maturation in early childhood using an objective approach.

METHODS

We collected frequency-following responses (FFR) to speech in 175 children, ages 3-8 years, annually for up to five years. The FFR is an objective measure of sound encoding that predominantly reflects auditory midbrain activity. Eliciting FFRs to speech provides rich details of various aspects of sound processing, namely, neural timing, spectral coding, and response stability. We used growth curve modeling to answer three questions: 1) does sound encoding change across childhood? 2) are there individual differences in sound encoding? and 3) are there individual differences in the development of sound encoding?

RESULTS

Subcortical auditory maturation develops linearly from 3-8 years. With age, FFRs became faster, more robust, and more consistent. Individual differences were evident in each aspect of sound processing, while individual differences in rates of change were observed for spectral coding alone.

CONCLUSIONS

By using an objective measure and a longitudinal approach, these results suggest subcortical auditory development continues throughout childhood, and that different facets of auditory processing follow distinct developmental trajectories.

SIGNIFICANCE

The present findings improve our understanding of auditory system development in typically-developing children, opening the door for future investigations of disordered sound processing in clinical populations.

School-age children benefit from voice gender cue differences for the perception of speech in competing speech

Differences in speakers' voice characteristics, such as mean fundamental frequency (F0) and vocal-tract length (VTL), that primarily define speakers' so-called perceived voice gender facilitate the perception of speech in competing speech. Perceiving speech in competing speech is particularly challenging for children, which may relate to their lower sensitivity to differences in voice characteristics than adults. This study investigated the development of the benefit from F0 and VTL differences in school-age children (4-12 years) for separating two competing speakers while tasked with comprehending one of them and also the relationship between this benefit and their corresponding voice discrimination thresholds. Children benefited from differences in F0, VTL, or both cues at all ages tested. This benefit proportionally remained the same across age, although overall accuracy continued to differ from that of adults. Additionally, children's benefit from F0 and VTL differences and their overall accuracy were not related to their discrimination thresholds. Hence, although children's voice discrimination thresholds and speech in competing speech perception abilities develop throughout the school-age years, children already show a benefit from voice gender cue differences early on. Factors other than children's discrimination thresholds seem to relate more closely to their developing speech in competing speech perception abilities.

Small-range numerical representations of linguistic sounds in 9- to 10-month-old infants

Coordinated studies provide evidence that very young infants, like human adults and nonhuman animals, readily discriminate small and large number of visual displays on the basis of numerical information. This capacity has been considerably less studied in the auditory modality. Surprisingly, the available studies yielded mixed evidence concerning whether numerical representations of auditory items in the small number range (1 to 3) are present early in human development. Specifically, while newborns discriminate 2- from 3-syllable sequences, older infants at 6 and 9 months of age fail to differentiate 2 from 3 tones. This study tested the hypothesis that infants can represent small sets more precisely when listening to ecologically relevant linguistic sounds. The aim was to probe 9- to 10-month-olds' (N = 74) ability to represent sound sets in a working memory test. In experiments 1 and 2, infants successfully discriminated 2- and 3-syllable sequences on the basis of their numerosity, when continuous variables, such as individual item duration, inter-stimulus duration, pitch, intensity, and total duration, were controlled for. In experiment 3, however, infants failed to discriminate 3- from 4-syllable sequences under similar conditions. Finally, in experiment 4, infants were tested on their ability to distinguish 2 and 3 tone sequences. The results showed no evidence that infants discriminated these non-linguistic stimuli. These findings indicate that, by means of linguistic sounds, infants can access a numerical system that yields precise auditory representations in the small number range.

Mandarin-speaking preschoolers' pitch discrimination, prosodic and phonological awareness, and their relation to receptive vocabulary and reading abilities

Cross-linguistic studies have reported that prosodic pattern awareness (e.g., lexical stress and lexical tone) is more important to reading acquisition than phonological awareness. However, few longitudinal studies have been conducted to explore the relations between these variables. This study examined preschoolers' pitch discrimination, prosodic and phonological awareness, and their connection to receptive vocabulary in preschool and reading abilities in first grade. Findings reveal (1) children improve their pitch discrimination and prosodic awareness from preschool to fourth grade; (2) pitch interval discrimination (frequency separation between tones) contributes to receptive vocabulary whereas pitch contour discrimination (patterns of rising and falling pitch) predicts word reading; (3) phonological awareness accounts for more variability in receptive vocabulary than prosodic awareness; whereas the reverse was found for word reading and reading comprehension. Together, prosody and its acoustic cue (i.e., pitch) play a vital role in learning to read Mandarin.

The Contribution of Frequency Discrimination Ability to Auditory Temporal Patterning Tests in Children

Purpose The Pitch Patterns Test (PPT) and the Duration Patterns Test (DPT) are clinical auditory processing tests that evaluate temporal patterning skills based on pitch (PPT) or duration (DPT) aspects of sound. Although temporal patterning tests are categorized under the temporal processing domain, successful performance on the PPT also relies on accurate pitch discrimination. However, the relationship between pitch discrimination ability and temporal patterning skills has not been thoroughly evaluated. This study examined the contribution of pitch discrimination ability to performance on temporal patterning in children through the use of a pitch discrimination task and the PPT. The DPT was also given as a control measure to assess temporal patterning with no pitch component. Method Thirty-two typically developing elementary school-age children (6;11-11;3 [years;months]) with normal hearing were given a series of three counterbalanced tasks: an adaptive psychophysical pitch discrimination task (difference limen for frequency [DLF]), the PPT, and the DPT. Results Correlational analysis revealed moderate correlations between DLF and PPT scores. After accounting for age, results of a linear regression analysis suggested that pitch discrimination accounts for a significant amount of variance in performance on the PPT. No significant correlation was found between DLF and DPT scores, supporting the hypothesis that the pitch task had no significant temporal patterning component contributing to the overall score. Discussion These findings indicate that pitch discrimination contributes significantly to performance on the PPT, but not the DPT, in a typically developing pediatric population. This is an important clinical consideration in both assessment and utilization of targeted therapy techniques for different clinical populations.

Interrater Reliability for a Two-Interval, Observer-Based Procedure for Measuring Hearing in Young Children

Purpose To overcome methodology limitations for studying auditory development in young children, we have recently developed an observer-based procedure that uses a conditioned, play-based, motor response (see Bonino & Leibold, 2017). The purpose of this article was to examine interrater reliability for the method. Method Video recordings of test sessions of 2- to 4-year-old children (n = 17) were examined. Detection of a 1000-Hz warble tone was measured with the Play Observer-Based, Two-Interval (PlayO2I) method in each of two conditions: for a fixed intensity level (30 dB SPL) or for a variable intensity level signal (0-30 dB SPL). All test sessions were scored independently by three observers (one real-time, two offline). Observer consensus was evaluated with Fleiss' kappa statistic. To determine if summary data were similar across the observers of each test session, the proportion of correct trials (fixed-level condition) or threshold (variable-level condition) were computed. Results The strength of observer consensus was classified as "almost perfect" and "substantial" for the fixed-level and variable-level conditions, respectively. Follow-up analysis of the variable-level data indicated that differences in observer consensus were seen based on the signal level, the type of response behavior provided by the child, and the confidence level of the real-time observer. Resulting summary data were similar across the three observers of each test session: no significant differences for estimates of the proportion of correct trials or threshold. Conclusions Results from this study confirm strong interrater reliability for the method. The PlayO2I method is a powerful tool for measuring detection and discrimination abilities in young children. Supplemental Material https://doi.org/10.23641/asha.12978197.

Feasibility of objective assessment of difference limen for intensity using acoustic change complex in children with central auditory processing disorder

INTRODUCTION

Acoustic change complex (ACC) shows brain's ability to discriminate between acoustic features in an ongoing stimulus. It is this nature of ACC that has generated interest in studying the usefulness of ACC as an objective tool for evaluating difference limens for various stimulus parameters. The present study therefore aimed at investigating the utility of ACC as an objective measure of difference limen for intensity (DLI) in normal hearing children with and without (C)APD.

METHODS

Fifteen children with (C)APD and 15 normal hearing children in whom (C)APD was ruled out (comparison group) in the age range of 8-12 years underwent ACC for 6 intensity differences (+1, +3, +4, +5, +10 & +20 dB) and a standard stimulus using a 1000 Hz stimulus.

RESULTS

Behavioral DLI (DLI_b) as well as DLI found using ACC (DLI_o) were both significantly larger in children with (C)APD than the comparison group (p < 0.05). Further, there was a significantly strong positive correlation between DLI_b and DLI_o (p < 0.001].

CONCLUSION

Outcome of the study provides evidence for the clinical use of ACC as an objective tool for examining DLI in children with (C)APD.

Involuntary Orienting and Conflict Resolution during Auditory Attention: The Role of Ventral and Dorsal Streams

Selective attention to sound object features such as pitch and location is associated with enhanced brain activity in ventral and dorsal streams, respectively. We examined the role of these pathways in involuntary orienting and conflict resolution using fMRI. Participants were presented with two tones that may, or may not, share the same nonspatial (frequency) or spatial (location) auditory features. In separate blocks of trials, participants were asked to attend to sound frequency or sound location and ignore the change in the task-irrelevant feature. In both attend-frequency and attend-location tasks, RTs were slower when the task-irrelevant feature changed than when it stayed the same (involuntary orienting). This behavioral cost coincided with enhanced activity in the pFC and superior temporal gyrus. Conflict resolution was examined by comparing situations where the change in stimulus features was congruent (both features changed) and incongruent (only one feature changed). Participants were slower and less accurate for incongruent than congruent sound features. This congruency effect was associated with enhanced activity in the pFC and was greater in the right superior temporal gyrus and medial frontal cortex during the attend-location task than during the attend-frequency task. Together, these findings do not support a strict division of "labor" into ventral and dorsal streams but rather suggest interactions between these pathways in situations involving changes in task-irrelevant sound feature and conflict resolution. These findings also validate the Test of Attention in Listening task by revealing distinct neural correlates for involuntary orienting and conflict resolution.

Development of voice perception is dissociated across gender cues in school-age children

Children's ability to distinguish speakers' voices continues to develop throughout childhood, yet it remains unclear how children's sensitivity to voice cues, such as differences in speakers' gender, develops over time. This so-called voice gender is primarily characterized by speakers' mean fundamental frequency (F0), related to glottal pulse rate, and vocal-tract length (VTL), related to speakers' size. Here we show that children's acquisition of adult-like performance for discrimination, a lower-order perceptual task, and categorization, a higher-order cognitive task, differs across voice gender cues. Children's discrimination was adult-like around the age of 8 for VTL but still differed from adults at the age of 12 for F0. Children's perceptual weight attributed to F0 for gender categorization was adult-like around the age of 6 but around the age of 10 for VTL. Children's discrimination and weighting of F0 and VTL were only correlated for 4- to 6-year-olds. Hence, children's development of discrimination and weighting of voice gender cues are dissociated, i.e., adult-like performance for F0 and VTL is acquired at different rates and does not seem to be closely related. The different developmental patterns for auditory discrimination and categorization highlight the complexity of the relationship between perceptual and cognitive mechanisms of voice perception.

Relationships between vocal pitch perception and production: a developmental perspective

The purpose of this study was to examine the relationships between vocal pitch discrimination abilities and vocal responses to auditory pitch-shifts. Twenty children (6.6-11.7 years) and twenty adults (18-28 years) completed a listening task to determine auditory discrimination abilities to vocal fundamental frequency (fo) as well as two vocalization tasks in which their perceived fo was modulated in real-time. These pitch-shifts were either unexpected, providing information on auditory feedback control, or sustained, providing information on sensorimotor adaptation. Children were subdivided into two groups based on their auditory pitch discrimination abilities; children within two standard deviations of the adult group were classified as having adult-like discrimination abilities (N = 11), whereas children outside of this range were classified as having less sensitive discrimination abilities than adults (N = 9). Children with less sensitive auditory pitch discrimination abilities had significantly larger vocal response magnitudes to unexpected pitch-shifts and significantly smaller vocal response magnitudes to sustained pitch-shifts. Children with less sensitive auditory pitch discrimination abilities may rely more on auditory feedback and thus may be less adept at updating their stored motor programs.

Developmental Effects in Children's Ability to Benefit From F0 Differences Between Target and Masker Speech

OBJECTIVES

The objectives of this study were to (1) evaluate the extent to which school-age children benefit from fundamental frequency (F0) differences between target words and competing two-talker speech, and (2) assess whether this benefit changes with age. It was predicted that while children would be more susceptible to speech-in-speech masking compared to adults, they would benefit from differences in F0 between target and masker speech. A second experiment was conducted to evaluate the relationship between frequency discrimination thresholds and the ability to benefit from target/masker differences in F0.

DESIGN

Listeners were children (5 to 15 years) and adults (20 to 36 years) with normal hearing. In the first experiment, speech reception thresholds (SRTs) for disyllabic words were measured in a continuous, 60-dB SPL two-talker speech masker. The same male talker produced both the target and masker speech (average F0 = 120 Hz). The level of the target words was adaptively varied to estimate the level associated with 71% correct identification. The procedure was a four-alternative forced-choice with a picture-pointing response. Target words either had the same mean F0 as the masker or it was shifted up by 3, 6, or 9 semitones. To determine the benefit of target/masker F0 separation on word recognition, masking release was computed by subtracting thresholds in each shifted-F0 condition from the threshold in the unshifted-F0 condition. In the second experiment, frequency discrimination thresholds were collected for a subset of listeners to determine whether sensitivity to F0 differences would be predictive of SRTs. The standard was the syllable /ba/ with an F0 of 250 Hz; the target stimuli had a higher F0. Discrimination thresholds were measured using a three-alternative, three-interval forced choice procedure.

RESULTS

Younger children (5 to 12 years) had significantly poorer SRTs than older children (13 to 15 years) and adults in the unshifted-F0 condition. The benefit of F0 separations generally increased with increasing child age and magnitude of target/masker F0 separation. For 5- to 7-year-olds, there was a small benefit of F0 separation in the 9-semitone condition only. For 8- to 12-year-olds, there was a benefit from both 6- and 9-semitone separations, but to a lesser degree than what was observed for older children (13 to 15 years) and adults, who showed a substantial benefit in the 6- and 9-semitone conditions. Examination of individual data found that children younger than 7 years of age did not benefit from any of the F0 separations tested. Results for the frequency discrimination task indicated that, while there was a trend for improved thresholds with increasing age, these thresholds were not predictive of the ability to use F0 differences in the speech-in-speech recognition task after controlling for age.

CONCLUSIONS

The overall pattern of results suggests that children's ability to benefit from F0 differences in speech-in-speech recognition follows a prolonged developmental trajectory. Younger children are less able to capitalize on differences in F0 between target and masker speech. The extent to which individual children benefitted from target/masker F0 differences was not associated with their frequency discrimination thresholds.

The development of auditory functions

Typical development and maturation of the auditory system, at both the peripheral and central levels, is essential for the acquisition of speech, language, and auditory skills. The peripheral system generally encodes three basic parameters associated with auditory stimuli-time, frequency, and intensity. These acoustic cues are subsequently processed by the central auditory structures to reach and be perceived by the cerebral cortex. Observations of the human fetal and neonatal ear indicate that the peripheral auditory system is structurally and functionally adult-like at birth. In contrast, the central auditory system exhibits progressive anatomical and physiologic changes until early adulthood. Enriched experience with sound is fundamental and critical to auditory development. The absence of early and prolonged acoustic stimulation delays neuronal maturation, affecting the central auditory nervous system, in particular, and leading to atypical development. The present chapter reviews the various stages of development of the auditory system structures, especially the embryology of the human ear, before briefly presenting the trajectories of typical development of auditory abilities from infants to school-aged children.

Auditory abilities stimulation in preschoolers

ABSTRACT Purpose: 1) to verify the intervention effects of an informal auditory training program to stimulate auditory abilities for sound localization and sequential memory for verbal and non-verbal sounds, at school environment in a group of preschoolers; 2) to investigate the influence of the gender and age variables on the result of the Simplified Auditory Processing Test (test and retest). Methods: a prospective, analytical and intervention study developed at a Municipal School of Early Childhood Education. Fifty-one preschool children of both genders, aged between 4 and 6 years, participated in this study. To evaluate the intervention effects of the informal auditory training program, pre-and post-intervention procedures were performed, that is: meatoscopy, tympanometry and Simplified Auditory Processing Test. Appropriate statistical tests were applied, by adopting the 5% (0.05) significance level. Results: the comparison of the preschoolers’ performance on the test and retest showed a significant improvement in all auditory abilities assessed. Preschoolers showed a better performance in sound localization ability and a worse performance for sequential memory of nonverbal sounds ability, for both test and retest. Conclusion: in this population, the informal auditory training program showed to be effective and the age variable influenced the result of the Simplified Auditory Processing Test.

Cognitive Abilities Contribute to Spectro-Temporal Discrimination in Children Who Are Hard of Hearing

OBJECTIVES

Spectral ripple discrimination tasks have received considerable interest as potential clinical tools for use with adults and children with hearing loss. Previous results have indicated that performance on ripple tasks is affected by differences in aided audibility [quantified using the Speech Intelligibility Index, or Speech Intelligibility Index (SII)] in children who wear hearing aids and that ripple thresholds tend to improve over time in children with and without hearing loss. Although ripple task performance is thought to depend less on language skills than common speech perception tasks, the extent to which spectral ripple discrimination might depend on other general cognitive abilities such as nonverbal intelligence and working memory is unclear. This is an important consideration for children because age-related changes in ripple test results could be due to developing cognitive ability and could obscure the effect of any changes in unaided or aided hearing over time. The purpose of this study was to establish the relationship between spectral ripple discrimination in a group of children who use hearing aids and general cognitive abilities such as nonverbal intelligence, visual and auditory working memory, and executive function. It was hypothesized that, after controlling for listener age, general cognitive ability would be associated with spectral ripple thresholds and performance on both auditory and visual cognitive tasks would be associated with spectral ripple thresholds.

DESIGN

Children who were full-time users of hearing aids for at least 1 year (n = 24, ages 6 to 13 years) participated in this study. Children completed a spectro-temporal modulated ripple discrimination task in the sound field using their personal hearing aids. Threshold was determined from the average of two repetitions of the task. Participants completed standard measurements of executive function, nonverbal intelligence, and visual and verbal working memory. Real ear verification measures were completed for each child with their personal hearing aids to determine aided SII.

RESULTS

Consistent with past findings, spectro-temporal ripple thresholds improved with greater listener age. Surprisingly, aided SII was not significantly correlated with spectro-temporal ripple thresholds potentially because this particular group of listeners had overall better hearing and greater aided SII than participants in previous studies. Partial correlations controlling for listener age revealed that greater nonverbal intelligence and visual working memory were associated with better spectro-temporal ripple discrimination thresholds. Verbal working memory, executive function, and language ability were not significantly correlated with spectro-temporal ripple discrimination thresholds.

CONCLUSIONS

These results indicate that greater general cognitive abilities are associated with better spectro-temporal ripple discrimination ability, independent of children's age or aided SII. It is possible that these relationships reflect the cognitive demands of the psychophysical task rather than a direct relationship of cognitive ability to spectro-temporal processing in the auditory system. Further work is needed to determine the relationships of cognitive abilities to ripple discrimination in other populations, such as children with cochlear implants or with a wider range of aided SII.

Behavioral Assessment of Hearing in 2- to 7-Year-Old Children: Evaluation of a Two-Interval, Observer-Based Procedure Using Conditioned Play-Based Responses

Purpose It is challenging to collect reliable behavioral data from toddlers and preschoolers. Consequently, we have significant gaps in our understanding of how auditory development unfolds during this time period. One method that appears to be promising is an observer-based procedure that uses conditioned, play-based responses (Bonino & Leibold, 2017). In order to evaluate the quality of data obtained with this method, this study presented a suprathreshold signal to determine the number of trials 2- to 7-year-old children could complete, as well as the associated hit rate and observer confidence. Method Participants were 23 children (2-7 years old). Children were taught to perform a play-based motor response when they detected the 1000-Hz warble tone signal (at 30 dB SPL). An observer evaluated children's behavior using a 2-interval, 2-alternative testing paradigm. Testing was terminated after 100 trials or earlier, if signs of habituation were observed. Results Data were successfully collected from 22 of the 23 children. Of the 22 children, all but 1 child completed 100 trials. Overall hit rate was high (0.88-1.0; M = 0.94) and improved with listener age. Hit rate was stable across the test session. Strong agreement was seen between the correctness of the response and the observer's confidence in the judgment. Conclusion Results of this study confirm that the 2-interval, observer-based procedure described in this article is a powerful tool for measuring detection and discrimination abilities in young children. Future research will (a) evaluate coder reliability and (b) examine stability of performance across a test session when the signal intensity is manipulated. Supplemental Material https://doi.org/10.23641/asha.8309273.

Musical playschool activities are linked to faster auditory development during preschool-age: a longitudinal ERP study

The influence of musical experience on brain development has been mostly studied in school-aged children with formal musical training while little is known about the possible effects of less formal musical activities typical for preschool-aged children (e.g., before the age of seven). In the current study, we investigated whether the amount of musical group activities is reflected in the maturation of neural sound discrimination from toddler to preschool-age. Specifically, we recorded event-related potentials longitudinally (84 recordings from 33 children) in a mismatch negativity (MMN) paradigm to different musically relevant sound changes at ages 2–3, 4–5 and 6–7 years from children who attended a musical playschool throughout the follow-up period and children with shorter attendance to the same playschool. In the first group, we found a gradual positive to negative shift in the polarities of the mismatch responses while the latter group showed little evidence of age-related changes in neural sound discrimination. The current study indicates that the maturation of sound encoding indexed by the MMN may be more protracted than once thought and provides first longitudinal evidence that even quite informal musical group activities facilitate the development of neural sound discrimination during early childhood.

Vocal Pitch Discrimination in Children with and without Vocal Fold Nodules

Vocal pitch discrimination abilities were compared in sixteen children with vocal fold nodules (CwVN) and sixteen matched controls with typical voices (CwTV). Vocal pitch discrimination was also evaluated in thirty-five vocally healthy children and twenty adults to examine potential changes as a function of maturation. CwTV were categorized as either younger (N = 15, 5.6-7.7 years) or older (N = 20, 8.2-11.7 years). Participants completed two-alternative, forced choice listening tasks in which they judged whether pairs of sustained /α/ tokens were different in pitch. Each pair consisted of a base token with a fundamental frequency fo ) of 216.2 Hz and a test token with a fo that was adaptively modified, according to the participant's prior judgments. There were no significant differences in pitch discrimination abilities between CwVN and CwTV. Pitch discrimination abilities were significantly poorer in younger and older CwTV as compared to adults. Additionally, younger CwTV had significantly poorer discrimination abilities than older CwTV. Findings from this study suggest that CwVN do not have differences in pitch discrimination abilities, yet, therapies designed for CwVN should consider this developmental trend in perceptual abilities.

Vowel Duration Discrimination of Children With Childhood Apraxia of Speech: A Preliminary Study

Purpose The ability of 5- and 6-year-old male children (23 participants) between the chronological ages of 5;0 and 6;11 (years;months) with childhood apraxia of speech (CAS; n = 9) and with typical development (TD; n = 14) to detect differences in vowel duration of syllable pairs is explored. We asked whether the children with CAS show different patterns of performance on the vowel duration difference experimental task than those of their similarly aged peers with TD. Method A male adult audio-recorded the syllable /bɑ/. The /ɑ/ was digitally lengthened and shortened, while maintaining uniform fundamental frequency and amplitude of the vowel and duration of the consonant /b/ at 42 ms. Vowel lengths increased in 40-ms increments, ranging from 208 to 488 ms. Eight pairs of syllables, 1 with equal length and 7 with differing vowel lengths, were randomly presented to the children 10 times in blocks of 16 pairs via a computer application. Results Numerous complementary analyses indicated patterns of performance differed for children with CAS compared to the children with TD. The children with CAS were notably less accurate in their duration discrimination and evidenced greater variability in their performances across duration difference conditions than their peers with TD, signifying they were generally challenged to discriminate the vowel duration differences. Conclusion These results suggest that CAS, which is more generally considered a motor speech disorder, may have a perceptual component of CAS related to vowel duration discrimination. Further research directions and clinical implications are discussed. Supplemental Material https://doi.org/10.23641/asha.8411876.

Spectral ripple discrimination in children with auditory processing disorder

Objective: The purpose of this study was to examine developmental trends in spectral ripple discrimination (SRD) and to compare the performance of typically developing children to children with auditory processing disorder (APD). Study design: Cross-sectional study. Study sample: Fifteen children with APD, as well as 17 typically developing children and 14 adults reporting no listening or academic difficulties participated. Results: Typically developing children showed poor SRD thresholds compared to adults, indicating prolonged maturation of spectral shape recognition. Both typically developing children and APD children showed a maturational trend in SRD, but a General Linear Model fit to their thresholds showed that children with APD displayed SRD thresholds that were significantly poorer than those of typically developing children when controlling for age. This suggests that in APD children, SRD maturation lags behind typically developing children. Conclusion: Poor spectral ripple discrimination may explain some of the listening difficulties experienced by children with APD.

Pspan: A New Tool for Assessing Pitch Temporal Processing and Patterning Capacity

Purpose The purpose of this study was to evaluate whether merging the clinical pitch pattern test procedure with psychoacoustic adaptive methods would create a new tool feasible to capture individual differences in pitch temporal processing and patterning capacity of children and adults. Method Sixty-six individuals, young children (ages 10-12 years, n = 22), older children (ages 13-15 years, n = 23), and adults (ages 18-33 years, n = 21), were recruited and assigned to subgroups based on reported duration (years) of instrumental music instruction. Additional background information was collected in order to assess if the pitch temporal processing and patterning span developed, the Pspan, was sensitive to individual differences across participants. Results The evaluation of the Pspan task as a scale indicated good parallel reliability across runs assessed by Cronbach's alpha, and scores were normally distributed. Between-subjects analysis of variance indicated main effects for both age groups and music groups recruited for the study. A multiple regression analysis with the Pspan scores as the dependent variable found that 3 measures of music instruction, age in years, and paternal education were predictive of enhanced temporal processing and patterning capacity for pitch input. Conclusions The outcomes suggest that the Pspan task is a time-efficient data collection tool that is sensitive to the duration of instrumental music instruction, maturation, and paternal education. In addition, results indicate that the task is sensitive to age-related auditory temporal processing and patterning performance changes during adolescence when children are 10-15 years old.

Amplitude modulation detection and temporal modulation cutoff frequency in normal hearing infants

The goal of this study was to determine if temporal modulation cutoff frequency was mature in three-month-old infants. Normal-hearing infants and young adults were tested in a single-interval forced-choice observer-based psychoacoustic procedure. Two parameters of the temporal modulation transfer function (TMTF) were estimated to separate temporal resolution from amplitude modulation sensitivity. The modulation detection threshold (MDT) of a broadband noise amplitude modulated at 10 Hz estimated the y-intercept of the TMTF. The cutoff frequency of the TMTF, measured at a modulation depth 4 dB greater than the MDT, provided an estimate of temporal resolution. MDT was obtained in 27 of 33 infants while both MDT and cutoff frequency was obtained in 15 infants and in 16 of 16 adults. Mean MDT was approximately 10 dB poorer in infants compared to adults. In contrast, mean temporal modulation cutoff frequency did not differ significantly between age groups. These results suggest that temporal resolution is mature, on average, by three months of age in normal hearing children despite immature sensitivity to amplitude modulation. The temporal modulation cutoff frequency approach used here may be a feasible way to examine development of temporal resolution in young listeners with markedly immature sensitivity to amplitude modulation.

Born to Speak and Sing: Musical Predictors of Language Development in Pre-schoolers

The relationship between musical and linguistic skills has received particular attention in infants and school-aged children. However, very little is known about pre-schoolers. This leaves a gap in our understanding of the concurrent development of these skills during development. Moreover, attention has been focused on the effects of formal musical training, while neglecting the influence of informal musical activities at home. To address these gaps, in Study 1, 3- and 4-year-old children (n = 40) performed novel musical tasks (perception and production) adapted for young children in order to examine the link between musical skills and the development of key language capacities, namely grammar and phonological awareness. In Study 2, we investigated the influence of informal musical experience at home on musical and linguistic skills of young pre-schoolers, using the same evaluation tools. We found systematic associations between distinct musical and linguistic skills. Rhythm perception and production were the best predictors of phonological awareness, while melody perception was the best predictor of grammar acquisition, a novel association not previously observed in developmental research. These associations could not be explained by variability in general cognitive functioning, such as verbal memory and non-verbal abilities. Thus, selective music-related auditory and motor skills are likely to underpin different aspects of language development and can be dissociated in pre-schoolers. We also found that informal musical experience at home contributes to the development of grammar. An effect of musical skills on both phonological awareness and language grammar is mediated by home musical experience. These findings pave the way for the development of dedicated musical activities for pre-schoolers to support specific areas of language development.

Long-Term Training-Induced Gains of an Auditory Skill in School-Age Children As Compared With Adults

The few studies that compared auditory skill learning between children and adults found variable results, with only some children reaching adult-like thresholds following training. The present study aimed to assess auditory skill learning in children as compared with adults during single- and multisession training. It was of interest to ascertain whether children who do not reach adult-like performance following a single training session simply require additional training, or whether different mechanisms underlying skill learning need to reach maturity in order to become adult-like performers. Forty children (7-9 years) and 45 young adults (18-35 years) trained in a single session. Of them, 20 children and 24 adults continued training for eight additional sessions. Each session included six frequency discrimination thresholds at 1000 Hz using adaptive forced-choice procedure. Retention of the learning-gains was tested 6 to 8 months posttraining. Results showed that (a) over half of the children presented similar performance and time course of learning as the adults. These children had better nonverbal reasoning and working memory abilities than their non-adult-like peers. (b) The best predicting factor for the outcomes of multisession training was a child's performance following one training session. (c) Performance gains were retained for all children with the non-adult-like children further improving, 6 to 8 months posttraining. Results suggest that mature auditory skill learning can emerge before puberty, provided that task-related cognitive mechanisms and task-specific sensory processing are already mature. Short-term training is sufficient, however, to reflect the maturity of these mechanisms, allowing the prediction of the efficiency of a prolonged training for a given child.

Dynamics of spontaneous alpha activity correlate with language ability in young children

Early childhood is a period of tremendous growth in both language ability and brain maturation. To understand the dynamic interplay between neural activity and spoken language development, we used resting-state EEG recordings to explore the relation between alpha oscillations (7-10 Hz) and oral language ability in 4- to 6-year-old children with typical development (N = 41). Three properties of alpha oscillations were investigated: a) alpha power using spectral analysis, b) flexibility of the alpha frequency quantified via the oscillation's moment-to-moment fluctuations, and c) scaling behavior of the alpha oscillator investigated via the long-range temporal correlation in the alpha-amplitude time course. All three properties of the alpha oscillator correlated with children's oral language abilities. Higher language scores were correlated with lower alpha power, greater flexibility of the alpha frequency, and longer temporal correlations in the alpha-amplitude time course. Our findings demonstrate a cognitive role of several properties of the alpha oscillator that has largely been overlooked in the literature.

Pure-Tone Frequency Discrimination in Preschoolers, Young School-Age Children, and Adults

PURPOSE

Published data indicate nearly adultlike frequency discrimination in infants but large child-adult differences for school-age children. This study evaluated the role that differences in measurement procedures and stimuli may have played in the apparent nonmonotonicity. Frequency discrimination was assessed in preschoolers, young school-age children, and adults using stimuli and procedures that have previously been used to test infants.

METHOD

Listeners were preschoolers (3-4 years), young school-age children (5-6 years), and adults (19-38 years). Performance was assessed using a single-interval, observer-based method and a continuous train of stimuli, similar to that previously used to evaluate infants. Testing was completed using 500- and 5000-Hz standard tones, fixed within a set of trials. Thresholds for frequency discrimination were obtained using an adaptive, two-down one-up procedure. Adults and most school-age children responded by raising their hands. An observer-based, conditioned-play response was used to test preschoolers and those school-age children for whom the hand-raise procedure was not effective for conditioning.

RESULTS

Results suggest an effect of age and frequency on thresholds but no interaction between these 2 factors. A lower proportion of preschoolers completed training compared with young school-age children. For those children who completed training, however, thresholds did not improve significantly with age; both groups of children performed more poorly than adults. Performance was better for the 500-Hz standard frequency compared with the 5000-Hz standard frequency.

CONCLUSIONS

Thresholds for school-age children were broadly similar to those previously observed using a forced-choice procedure. Although there was a trend for improved performance with increasing age, no significant age effect was observed between preschoolers and school-age children. The practice of excluding participants based on failure to meet conditioning criteria in an observer-based task could contribute to the relatively good performance observed for preschoolers in this study and the adultlike performance previously observed in infants.

Psychophysics with children: Investigating the effects of attentional lapses on threshold estimates

When assessing the perceptual abilities of children, researchers tend to use psychophysical techniques designed for use with adults. However, children's poorer attentiveness might bias the threshold estimates obtained by these methods. Here, we obtained speed discrimination threshold estimates in 6- to 7-year-old children in UK Key Stage 1 (KS1), 7- to 9-year-old children in Key Stage 2 (KS2), and adults using three psychophysical procedures: QUEST, a 1-up 2-down Levitt staircase, and Method of Constant Stimuli (MCS). We estimated inattentiveness using responses to "easy" catch trials. As expected, children had higher threshold estimates and made more errors on catch trials than adults. Lower threshold estimates were obtained from psychometric functions fit to the data in the QUEST condition than the MCS and Levitt staircases, and the threshold estimates obtained when fitting a psychometric function to the QUEST data were also lower than when using the QUEST mode. This suggests that threshold estimates cannot be compared directly across methods. Differences between the procedures did not vary significantly with age group. Simulations indicated that inattentiveness biased threshold estimates particularly when threshold estimates were computed as the QUEST mode or the average of staircase reversals. In contrast, thresholds estimated by post-hoc psychometric function fitting were less biased by attentional lapses. Our results suggest that some psychophysical methods are more robust to attentiveness, which has important implications for assessing the perception of children and clinical groups.

Music and Speech Perception in Children Using Sung Speech

This study examined music and speech perception in normal-hearing children with some or no musical training. Thirty children (mean age = 11.3 years), 15 with and 15 without formal music training participated in the study. Music perception was measured using a melodic contour identification (MCI) task; stimuli were a piano sample or sung speech with a fixed timbre (same word for each note) or a mixed timbre (different words for each note). Speech perception was measured in quiet and in steady noise using a matrix-styled sentence recognition task; stimuli were naturally intonated speech or sung speech with a fixed pitch (same note for each word) or a mixed pitch (different notes for each word). Significant musician advantages were observed for MCI and speech in noise but not for speech in quiet. MCI performance was significantly poorer with the mixed timbre stimuli. Speech performance in noise was significantly poorer with the fixed or mixed pitch stimuli than with spoken speech. Across all subjects, age at testing and MCI performance were significantly correlated with speech performance in noise. MCI and speech performance in quiet was significantly poorer for children than for adults from a related study using the same stimuli and tasks; speech performance in noise was significantly poorer for young than for older children. Long-term music training appeared to benefit melodic pitch perception and speech understanding in noise in these pediatric listeners.

The Effects of Acoustic Bandwidth on Simulated Bimodal Benefit in Children and Adults with Normal Hearing

OBJECTIVES

The primary purpose of this study was to examine the effect of acoustic bandwidth on bimodal benefit for speech recognition in normal-hearing children with a cochlear implant (CI) simulation in one ear and low-pass filtered stimuli in the contralateral ear. The effect of acoustic bandwidth on bimodal benefit in children was compared with the pattern of adults with normal hearing. Our hypothesis was that children would require a wider acoustic bandwidth than adults to (1) derive bimodal benefit, and (2) obtain asymptotic bimodal benefit.

DESIGN

Nineteen children (6 to 12 years) and 10 adults with normal hearing participated in the study. Speech recognition was assessed via recorded sentences presented in a 20-talker babble. The AzBio female-talker sentences were used for the adults and the pediatric AzBio sentences (BabyBio) were used for the children. A CI simulation was presented to the right ear and low-pass filtered stimuli were presented to the left ear with the following cutoff frequencies: 250, 500, 750, 1000, and 1500 Hz.

RESULTS

The primary findings were (1) adults achieved higher performance than children when presented with only low-pass filtered acoustic stimuli, (2) adults and children performed similarly in all the simulated CI and bimodal conditions, (3) children gained significant bimodal benefit with the addition of low-pass filtered speech at 250 Hz, and (4) unlike previous studies completed with adult bimodal patients, adults and children with normal hearing gained additional significant bimodal benefit with cutoff frequencies up to 1500 Hz with most of the additional benefit gained with energy below 750 Hz.

CONCLUSIONS

Acoustic bandwidth effects on simulated bimodal benefit were similar in children and adults with normal hearing. Should the current results generalize to children with CIs, these results suggest pediatric CI recipients may derive significant benefit from minimal acoustic hearing (<250 Hz) in the nonimplanted ear and increasing benefit with broader bandwidth. Knowledge of the effect of acoustic bandwidth on bimodal benefit in children may help direct clinical decisions regarding a second CI, continued bimodal hearing, and even optimizing acoustic amplification for the nonimplanted ear.

Cortical hemispheric asymmetries are present at young ages and further develop into adolescence

Specialization of the auditory cortices for pure tone listening may develop with age. In adults, the right hemisphere dominates when listening to pure tones and music; we thus hypothesized that (a) asymmetric function between auditory cortices increases with age and (b) this development is specific to tonal rather than broadband/non-tonal stimuli. Cortical responses to tone-bursts and broadband click-trains were recorded by multichannel electroencephalography in young children (5.1 ± 0.8 years old) and adolescents (15.2 ± 1.7 years old) with normal hearing. Peak dipole moments indicating activity strength in right and left auditory cortices were calculated using the Time Restricted, Artefact and Coherence source Suppression (TRACS) beamformer. Monaural click-trains and tone-bursts in young children evoked a dominant response in the contralateral right cortex by left ear stimulation and, similarly, a contralateral left cortex response to click-trains in the right ear. Responses to tone-bursts in the right ear were more bilateral. In adolescents, peak activity dominated in the right cortex in most conditions (tone-bursts from either ear and to clicks from the left ear). Bilateral activity was evoked by right ear click stimulation. Thus, right hemispheric specialization for monaural tonal stimuli begins in children as young as 5 years of age and becomes more prominent by adolescence. These changes were marked by consistent dipole moments in the right auditory cortex with age in contrast to decreases in dipole activity in all other stimulus conditions. Together, the findings reveal increasingly asymmetric function for the two auditory cortices, potentially to support greater cortical specialization with development into adolescence.

The development of categorical perception of Mandarin tones in four- to seven-year-old children

To track the course of development in children's fine-grained perception of Mandarin tones, the present study explored how categorical perception (CP) of Mandarin tones emerges along age among 70 four- to seven-year-old children and 16 adults. Prominent discrimination peaks were found for both the child and the adult groups, and they were well aligned with the corresponding identification crossovers. Moreover, six-year-olds showed a much narrower width (i.e. a sharper slope) compared to younger children, and have already acquired adult-like identification competence of Mandarin high-level and mid-rising tones. Although the ability to discriminate within-category tone pairs did not change, the between-category discrimination accuracies were positively correlated with chronological ages among child participants. We assume that the perceptual refinement of Mandarin tones in young children may be driven by an accumulation of perceptual development from the tonal information of the ambient sound input.

Developmental Fine-tuning of Human Olfactory Discriminability

Unlike vision or audition, human olfaction is generally considered evolutionarily ancient and well-functioning at birth, yet there have been few empirical data on the development of olfactory acuity. The current study has assessed olfactory discriminability in children aged 3 to 6 years with 16 pairs of single-compound odorants that differ in various degrees in structure and smell. We report a significant improvement over age in young children's overall olfactory discriminability. Critically, such improvement is modulated by the degree of structural similarity between odorants independent of odor familiarity. Our findings indicate that odor representations in the olfactory system are fine-tuned during early childhood (3-6 years of age) to allow refined discrimination. Moreover, they suggest the need to take molecular similarity into consideration in the evaluation of olfactory discrimination in pediatric populations.

Neural correlates of distraction and conflict resolution for nonverbal auditory events

In everyday situations auditory selective attention requires listeners to suppress task-irrelevant stimuli and to resolve conflicting information in order to make appropriate goal-directed decisions. Traditionally, these two processes (i.e. distractor suppression and conflict resolution) have been studied separately. In the present study we measured neuroelectric activity while participants performed a new paradigm in which both processes are quantified. In separate block of trials, participants indicate whether two sequential tones share the same pitch or location depending on the block’s instruction. For the distraction measure, a positive component peaking at ~250 ms was found – a distraction positivity. Brain electrical source analysis of this component suggests different generators when listeners attended to frequency and location, with the distraction by location more posterior than the distraction by frequency, providing support for the dual-pathway theory. For the conflict resolution measure, a negative frontocentral component (270–450 ms) was found, which showed similarities with that of prior studies on auditory and visual conflict resolution tasks. The timing and distribution are consistent with two distinct neural processes with suppression of task-irrelevant information occurring before conflict resolution. This new paradigm may prove useful in clinical populations to assess impairments in filtering out task-irrelevant information and/or resolving conflicting information.

Discrimination and Identification of a Third Formant Frequency Cue to Place of Articulation by Young Children and Adults

Typically-developing children, 4 to 6 years of age, and adults participated in discrimination and identification speech perception tasks using a synthetic consonant-vowel continuum ranging from /da/ to /ga/. The seven-step synthetic /da/-/ga/ continuum was created by adjusting the first 40 ms of the third formant frequency transition. For the discrimination task, listeners participated in a Change/No-Change paradigm with four different stimuli compared to the endpoint-1 /da/ token. For the identification task, listeners labeled each token along the /da/-/ga/ continuum as either "DA" or "GA." Results of the discrimination experiment showed that sensitivity to the third-formant transition cue improved for the adult listeners as the stimulus contrast increased, whereas the performance of the children remained poor across all stimulus comparisons. Results of the identification experiment support previous hypotheses of age-related differences in phonetic categorization. Results have implications for normative data on identification and discrimination tasks. These norms provide a metric against which children with auditory-based speech sound disorders can be compared. Furthermore, the results provide some insight into the developmental nature of categorical and non-categorical speech perception.

Developmental trajectories of pitch-related music skills in children with Williams syndrome

The study of music cognition in Williams syndrome (WS) has resulted in theoretical debates regarding cognitive modularity and development. However, no research has previously investigated the development of music skills in this population. In this study, we used the cross-sectional developmental trajectories approach to assess the development of pitch-related music skills in children with WS compared with typically developing (TD) peers. Thus, we evaluated the role of change over time on pitch-related music skills and the developmental relationships between music skills and different cognitive areas. In the TD children, the pitch-related music skills improved with chronological age and cognitive development. In the children with WS, developmental relationships were only found between several pitch-related music skills and specific cognitive processes. We also found non-systematic relationships between chronological age and the pitch-related music skills, stabilization in the level reached in music when cognitive development was considered, and uneven associations between cognitive and music skills. In addition, the TD and WS groups differed in their patterns of pitch-related music skill development. These results suggest that the development of pitch-related music skills in children with WS is atypical. Our findings stand in contrast with the views that claim innate modularity for music in WS; rather, they are consistent with neuroconstructivist accounts.

Spectro-temporal modulation detection in children

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.

Cortical Representations Sensitive to the Number of Perceived Auditory Objects Emerge between 2 and 4 Months of Age: Electrophysiological Evidence

Sound waves emitted by two or more simultaneous sources reach the ear as one complex waveform. Auditory scene analysis involves parsing a complex waveform into separate perceptual representations of the sound sources [Bregman, A. S. Auditory scene analysis: The perceptual organization of sounds. London: MIT Press, 1990]. Harmonicity provides an important cue for auditory scene analysis. Normally, harmonics at integer multiples of a fundamental frequency are perceived as one sound with a pitch corresponding to the fundamental frequency. However, when one harmonic in such a complex, pitch-evoking sound is sufficiently mistuned, that harmonic emerges from the complex tone and is perceived as a separate auditory object. Previous work has shown that the percept of two objects is indexed in both children and adults by the object-related negativity component of the ERP derived from EEG recordings [Alain, C., Arnott, S. T., & Picton, T. W. Bottom–up and top–down influences on auditory scene analysis: Evidence from event-related brain potentials. Journal of Experimental Psychology: Human Perception and Performance, 27, 1072–1089, 2001]. Here we examine the emergence of object-related responses to an 8% harmonic mistuning in infants between 2 and 12 months of age. Two-month-old infants showed no significant object-related response. However, in 4- to 12-month-old infants, a significant frontally positive component was present, and by 8–12 months, a significant frontocentral object-related negativity was present, similar to that seen in older children and adults. This is in accordance with previous research demonstrating that infants younger than 4 months of age do not integrate harmonic information to perceive pitch when the fundamental is missing [He, C., Hotson, L., & Trainor, L. J. Maturation of cortical mismatch mismatch responses to occasional pitch change in early infancy: Effects of presentation rate and magnitude of change. Neuropsychologia, 47, 218–229, 2009]. The results indicate that the ability to use harmonic information to segregate simultaneous sounds emerges at the cortical level between 2 and 4 months of age.

Development and validation of a new Mandarin tone identification test

OBJECTIVES

The objectives of this study were to develop a new Mandarin tone identification test (MTIT) to assess the Mandarin tone identification ability of children with hearing impairment (HI) and at age around 7 years; and to evaluate the reliability and sensitivity of the MTIT.

METHODS

The word materials to be used in the MTIT were developed in Phase I. Monosyllables were chosen to represent the daily repertoire of young children and to avoid the influence of co-articulation and intonation. Each test stimulus set contained four words, with one target, one containing contrastive tone, and two unrelated distracters. All words were depicted using simple pictures, and the test targets in quiet or in noise were presented using recorded stimuli on a custom software. Phase II evaluated the reliability and sensitivity of the MTIT. Participants were 50 normal-hearing native-Mandarin speakers around 7 years of age.

RESULTS

In Phase I, the MTIT was developed as described above. The final test consists of 51 words that are within the vocabulary repertoire of children aged 7 years. In Phase II, with the Mandarin tone identification scores collected from 50 children, the repeated measure ANOVA showed a significant main effect of S/N on MTIT performance (p<0.001). Pairwise comparisons revealed a significant difference in performance across the five S/N conditions (p<0.01) when S/N varied from -30 to -10dB. Cronbach's alpha at -15dB S/N was 0.66, suggesting satisfactory internal consistency reliability. A paired-samples t-test showed that there was no significant difference between the test-retest scores across the five S/N conditions (p>0.05).

CONCLUSIONS

Compared with the available Mandarin tone identification tools, MTIT systematically evaluated the tone identification performance in noisy environment for normal hearing children at age around 7 years. Results also showed satisfactory internal consistency reliability, good test-retest reliability and good sensitivity. In the near future, MTIT could be used to evaluate tone perception ability of children with hearing impairment and help to design hearing rehabilitation strategies for this population at the age critical for their language learning.

Factors affecting sensitivity to frequency change in school-age children and adults

PURPOSE

The factors affecting frequency discrimination in school-age children are poorly understood. The goal of the present study was to evaluate developmental effects related to memory for pitch and the utilization of temporal fine structure.

METHOD

Listeners were 5.1- to 13.6-year-olds and adults, all with normal hearing. A subgroup of children had musical training. The task was a 3-alternative forced choice in which listeners identified the interval with the higher frequency tone or the tone characterized by frequency modulation (FM). The standard was 500 or 5000 Hz, and the FM rate was either 2 or 20 Hz.

RESULTS

Thresholds tended to be higher for younger children than for older children and adults for all conditions, although this age effect was smaller for FM detection than for pure-tone frequency discrimination. Neither standard frequency nor modulation rate affected the child/adult difference FM thresholds. Children with musical training performed better than their peers on pure-tone frequency discrimination at 500 Hz.

CONCLUSIONS

Testing frequency discrimination using a low-rate FM detection task may minimize effects related to cognitive factors like memory for pitch or training effects. Maturation of frequency discrimination does not appear to differ across conditions in which listeners are hypothesized to rely on temporal cues and place cues.