Children build their vocabularies in noisy environments: The necessity of a cross-disciplinary approach to understand word learning.

Research within the language sciences has informed our understanding of how children build vocabulary knowledge especially during early childhood and the early school years. However, to date, our understanding of word learning in children is based primarily on research in quiet laboratory settings. The everyday environments that children inhabit such as schools, homes, and day cares are typically noisy. To better understand vocabulary development, we need to understand the effects of background noise on word learning. To gain this understanding, a cross-disciplinary approach between researchers in the language and hearing sciences in partnership with parents, educators, and clinicians is ideal. Through this approach we can identify characteristics of effective vocabulary instruction that take into account the background noise present in children's learning environments. Furthermore, we can identify characteristics of children who are likely to struggle with learning words in noisy environments. For example, differences in vocabulary knowledge, verbal working memory abilities, and attention skills will likely influence children's ability to learn words in the presence of background noise. These children require effective interventions to support their vocabulary development which subsequently should support their ability to process and learn language in noisy environments. Overall, this cross-disciplinary approach will inform theories of language development and inform educational and intervention practices designed to support children's vocabulary development. This article is categorized under: Psychology > Language Psychology > Learning Psychology > Theory and Methods.

Comparing Scores on the Peabody Picture Vocabulary Test and Receptive One-Word Picture Vocabulary Test in Preschoolers With and Without Hearing Loss.

PURPOSE: We sought to compare raw scores, standard scores, and age equivalences on two commonly used vocabulary tests, the Peabody Picture Vocabulary Test (PPVT) and the Receptive One-Word Picture Vocabulary Test (ROWPVT). METHOD: Sixty-two children, 31 with hearing loss (HL) and 31 with normal hearing (NH), were given both the PPVT and ROWPVT as part of an ongoing longitudinal study of emergent literacy development in preschoolers with and without HL. All children were between 3 and 4 years old at administration, and the two tests were administered within 3 weeks of each other. Both tests were given again 6 months later. Standard scores and age equivalencies were calculated for both tests using published guidelines. RESULTS: There was no significant effect of test for any of our analyses. However, there was a main effect of time, with both standard scores and age equivalencies being significantly higher at the second test. Children with NH had significantly higher standard scores and age equivalencies than children with NH, but there was no interaction between hearing status and time, suggesting that the two groups were growing at the same rate. CONCLUSIONS: Clinicians can be comfortable administering both the PPVT and ROWPVT to estimate children's vocabulary levels, but there may be practice effects when administering the tests twice within a calendar year. These data also indicate that children with HL continue to lag behind their peers with NH on vocabulary development. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.23232848.

Age and Hearing Ability Influence Selective Attention During Childhood.

OBJECTIVES: The purpose of the present study was to determine whether age and hearing ability influence selective attention during childhood. Specifically, we hypothesized that immaturity and disrupted auditory experience impede selective attention during childhood. DESIGN: Seventy-seven school-age children (5 to 12 years of age) participated in this study: 61 children with normal hearing and 16 children with bilateral hearing loss who use hearing aids and/or cochlear implants. Children performed selective attention-based behavioral change detection tasks comprised of target and distractor streams in the auditory and visual modalities. In the auditory modality, children were presented with two streams of single-syllable words spoken by a male and female talker. In the visual modality, children were presented with two streams of grayscale images. In each task, children were instructed to selectively attend to the target stream, inhibit attention to the distractor stream, and press a key as quickly as possible when they detected a frequency (auditory modality) or color (visual modality) deviant stimulus in the target, but not distractor, stream. Performance on the auditory and visual change detection tasks was quantified by response sensitivity, which reflects children's ability to selectively attend to deviants in the target stream and inhibit attention to those in the distractor stream. Children also completed a standardized measure of attention and inhibitory control. RESULTS: Younger children and children with hearing loss demonstrated lower response sensitivity, and therefore poorer selective attention, than older children and children with normal hearing, respectively. The effect of hearing ability on selective attention was observed across the auditory and visual modalities, although the extent of this group difference was greater in the auditory modality than the visual modality due to differences in children's response patterns. Additionally, children's performance on a standardized measure of attention and inhibitory control related to their performance during the auditory and visual change detection tasks. CONCLUSIONS: Overall, the findings from the present study suggest that age and hearing ability influence children's ability to selectively attend to a target stream in both the auditory and visual modalities. The observed differences in response patterns across modalities, however, reveal a complex interplay between hearing ability, task modality, and selective attention during childhood. While the effect of age on selective attention is expected to reflect the immaturity of cognitive and linguistic processes, the effect of hearing ability may reflect altered development of selective attention due to disrupted auditory experience early in life and/or a differential allocation of attentional resources to meet task demands.

The Impact of Hearing Experience on Children's Use of Phonological and Semantic Information During Lexical Access.

Purpose The purpose of this study was to examine the extent to which phonological competition and semantic priming influence lexical access in school-aged children with cochlear implants (CIs) and children with normal acoustic hearing. Method Participants included children who were 5-10 years of age with either normal hearing (n = 41) or bilateral severe to profound sensorineural hearing loss and used CIs (n = 13). All participants completed a two-alternative forced-choice task while eye gaze to visual images was recorded and quantified during a word recognition task. In this task, the target image was juxtaposed with a competitor image that was either a phonological onset competitor (i.e., shared the same initial consonant-vowel-consonant syllable as the target) or an unrelated distractor. Half of the trials were preceded by an image prime that was semantically related to the target image. Results Children with CIs showed evidence of phonological competition during real-time processing of speech. This effect, however, was less and occurred later in the time course of speech processing than what was observed in children with normal hearing. The presence of a semantically related visual prime reduced the effects of phonological competition in both groups of children but to a greater degree in children with CIs. Conclusions Children with CIs were able to process single words similarly to their counterparts with normal hearing. However, children with CIs appeared to have increased reliance on surrounding semantic information compared to their normal-hearing counterparts.

Rethinking Emergent Literacy in Children With Hearing Loss.

Long-term literacy outcomes for children with hearing loss, particularly those with severe-to-profound deafness who are fitted with cochlear implants (CIs) lag behind those of children with normal hearing (NH). The causes for these long-term deficits are not fully clear, though differences in auditory access between children who use CIs and those with NH may be a partial cause. This paper briefly reviews the emergent literacy model as proposed by Whitehurst and Lonigan (1998). We then examine the development of each of Whitehurst and Lonigan's identified factors in children who use CIs and how the extant knowledge of language and literacy development in children who use CIs may bear on the emergent literacy model. We then propose to modify the model for children who use CIs based on their unique developmental trajectories, influenced at least in part by their unique auditory access. We conclude with future directions for further development of an evidence-based emergent literacy model for children who use CIs and how this model could be used to inform intervention.

Quantifying the Effects of Background Speech Babble on Preschool Children's Novel Word Learning in a Multisession Paradigm: A Preliminary Study.

Purpose This study tested the effects of background speech babble on novel word learning in preschool children with a multisession paradigm. Method Eight 3-year-old children were exposed to a total of 8 novel word-object pairs across 2 story books presented digitally. Each story contained 4 novel consonant-vowel-consonant nonwords. Children were exposed to both stories, one in quiet and one in the presence of 4-talker babble presented at 0-dB signal-to-noise ratio. After each story, children's learning was tested with a referent selection task and a verbal recall (naming) task. Children were exposed to and tested on the novel word-object pairs on 5 separate days within a 2-week span. Results A significant main effect of session was found for both referent selection and verbal recall. There was also a significant main effect of exposure condition on referent selection performance, with more referents correctly selected for word-object pairs that were presented in quiet compared to pairs presented in speech babble. Finally, children's verbal recall of novel words was statistically better than baseline performance (i.e., 0%) on Sessions 3-5 for words exposed in quiet, but only on Session 5 for words exposed in speech babble. Conclusions These findings suggest that background speech babble at 0-dB signal-to-noise ratio disrupts novel word learning in preschool-age children. As a result, children may need more time and more exposures of a novel word before they can recognize or verbally recall it.

Background Speech Disrupts Working Memory Span in 5-Year-Old Children.

OBJECTIVES: The present study tested the effects of background speech and nonspeech noise on 5-year-old children's working memory span. DESIGN: Five-year-old typically developing children (range = 58.6 to 67.6 months; n = 94) completed a modified version of the Missing Scan Task, a missing-item working memory task, in quiet and in the presence of two types of background noise: male two-talker speech and speech-shaped noise. The two types of background noise had similar spectral composition and overall intensity characteristics but differed in whether they contained verbal content. In Experiments 1 and 2, children's memory span (i.e., the largest set size of items children successfully recalled) was subjected to analyses of variance designed to look for an effect of listening condition (within-subjects factor: quiet, background noise) and an effect of background noise type (between-subjects factor: two-talker speech, speech-shaped noise). RESULTS: In Experiment 1, children's memory span declined in the presence of two-talker speech but not in the presence of speech-shaped noise. This result was replicated in Experiment 2 after accounting for a potential effect of proactive interference due to repeated administration of the Missing Scan Task. CONCLUSIONS: Background speech, but not speech-shaped noise, disrupted working memory span in 5-year-old children. These results support the idea that background speech engages domain-general cognitive processes used during the recall of known objects in a way that speech-shaped noise does not.

Belief Shift or Only Facilitation: How Semantic Expectancy Affects Processing of Speech Degraded by Background Noise.

Individuals use semantic expectancy - applying conceptual and linguistic knowledge to speech input - to improve the accuracy and speed of language comprehension. This study tested how adults use semantic expectancy in quiet and in the presence of speech-shaped broadband noise at -7 and -12 dB signal-to-noise ratio. Twenty-four adults (22.1 ± 3.6 years, mean ±SD) were tested on a four-alternative-forced-choice task whereby they listened to sentences and were instructed to select an image matching the sentence-final word. The semantic expectancy of the sentences was unrelated to (neutral), congruent with, or conflicting with the acoustic target. Congruent expectancy improved accuracy and conflicting expectancy decreased accuracy relative to neutral, consistent with a theory where expectancy shifts beliefs toward likely words and away from unlikely words. Additionally, there were no significant interactions of expectancy and noise level when analyzed in log-odds, supporting the predictions of ideal observer models of speech perception.

Neural preservation underlies speech improvement from auditory deprivation in young cochlear implant recipients.

Although cochlear implantation enables some children to attain age-appropriate speech and language development, communicative delays persist in others, and outcomes are quite variable and difficult to predict, even for children implanted early in life. To understand the neurobiological basis of this variability, we used presurgical neural morphological data obtained from MRI of individual pediatric cochlear implant (CI) candidates implanted younger than 3.5 years to predict variability of their speech-perception improvement after surgery. We first compared neuroanatomical density and spatial pattern similarity of CI candidates to that of age-matched children with normal hearing, which allowed us to detail neuroanatomical networks that were either affected or unaffected by auditory deprivation. This information enables us to build machine-learning models to predict the individual children's speech development following CI. We found that regions of the brain that were unaffected by auditory deprivation, in particular the auditory association and cognitive brain regions, produced the highest accuracy, specificity, and sensitivity in patient classification and the most precise prediction results. These findings suggest that brain areas unaffected by auditory deprivation are critical to developing closer to typical speech outcomes. Moreover, the findings suggest that determination of the type of neural reorganization caused by auditory deprivation before implantation is valuable for predicting post-CI language outcomes for young children.

Multitasking During Degraded Speech Recognition in School-Age Children.

Multitasking requires individuals to allocate their cognitive resources across different tasks. The purpose of the current study was to assess school-age children's multitasking abilities during degraded speech recognition. Children (8 to 12 years old) completed a dual-task paradigm including a sentence recognition (primary) task containing speech that was either unprocessed or noise-band vocoded with 8, 6, or 4 spectral channels and a visual monitoring (secondary) task. Children's accuracy and reaction time on the visual monitoring task was quantified during the dual-task paradigm in each condition of the primary task and compared with single-task performance. Children experienced dual-task costs in the 6- and 4-channel conditions of the primary speech recognition task with decreased accuracy on the visual monitoring task relative to baseline performance. In all conditions, children's dual-task performance on the visual monitoring task was strongly predicted by their single-task (baseline) performance on the task. Results suggest that children's proficiency with the secondary task contributes to the magnitude of dual-task costs while multitasking during degraded speech recognition.

Word segmentation from noise-band vocoded speech.

Spectral degradation reduces access to the acoustics of spoken language and compromises how learners break into its structure. We hypothesised that spectral degradation disrupts word segmentation, but that listeners can exploit other cues to restore detection of words. Normal-hearing adults were familiarised to artificial speech that was unprocessed or spectrally degraded by noise-band vocoding into 16 or 8 spectral channels. The monotonic speech stream was pause-free (Experiment 1), interspersed with isolated words (Experiment 2), or slowed by 33% (Experiment 3). Participants were tested on segmentation of familiar vs. novel syllable sequences and on recognition of individual syllables. As expected, vocoding hindered both word segmentation and syllable recognition. The addition of isolated words, but not slowed speech, improved segmentation. We conclude that syllable recognition is necessary but not sufficient for successful word segmentation, and that isolated words can facilitate listeners' access to the structure of acoustically degraded speech.

Age-Related Differences in Listening Effort During Degraded Speech Recognition.

OBJECTIVES: The purpose of the present study was to quantify age-related differences in executive control as it relates to dual-task performance, which is thought to represent listening effort, during degraded speech recognition. DESIGN: Twenty-five younger adults (YA; 18-24 years) and 21 older adults (OA; 56-82 years) completed a dual-task paradigm that consisted of a primary speech recognition task and a secondary visual monitoring task. Sentence material in the primary task was either unprocessed or spectrally degraded into 8, 6, or 4 spectral channels using noise-band vocoding. Performance on the visual monitoring task was assessed by the accuracy and reaction time of participants' responses. Performance on the primary and secondary task was quantified in isolation (i.e., single task) and during the dual-task paradigm. Participants also completed a standardized psychometric measure of executive control, including attention and inhibition. Statistical analyses were implemented to evaluate changes in listeners' performance on the primary and secondary tasks (1) per condition (unprocessed vs. vocoded conditions); (2) per task (single task vs. dual task); and (3) per group (YA vs. OA). RESULTS: Speech recognition declined with increasing spectral degradation for both YA and OA when they performed the task in isolation or concurrently with the visual monitoring task. OA were slower and less accurate than YA on the visual monitoring task when performed in isolation, which paralleled age-related differences in standardized scores of executive control. When compared with single-task performance, OA experienced greater declines in secondary-task accuracy, but not reaction time, than YA. Furthermore, results revealed that age-related differences in executive control significantly contributed to age-related differences on the visual monitoring task during the dual-task paradigm. CONCLUSIONS: OA experienced significantly greater declines in secondary-task accuracy during degraded speech recognition than YA. These findings are interpreted as suggesting that OA expended greater listening effort than YA, which may be partially attributed to age-related differences in executive control.

Spatial acuity in 2-to-3-year-old children with normal acoustic hearing, unilateral cochlear implants, and bilateral cochlear implants.

OBJECTIVES: : To measure spatial acuity on a right-left discrimination task in 2-to-3-year-old children who use a unilateral cochlear implant (UCI) or bilateral cochlear implants (BICIs); to test the hypothesis that BICI users perform significantly better when they use two CIs than when using a single CI, and that they perform better than the children in the UCI group; to determine how well children with CIs perform compared with children who have normal acoustic hearing (NH); to determine the effect of intensity roving on spatial acuity. DESIGN: : Three groups of children between 26 and 36 months of age participated in this study: 8 children with NH (mean age: 30.9 months), 12 children who use a UCI (mean age: 31.9 months), and 27 children who use BICIs (mean age: 30.7 months). Testing was conducted in a large sound-treated booth with loudspeakers positioned in a horizontal arc with a radius of 1.2 m. The observer-based psychophysical procedure was used to measure the children's ability to identify the hemifield containing the sound source (right versus left). Two methods were used for quantifying spatial acuity, an adaptive-tracking method and a fixed-angle method. In Experiment 1 an adaptive tracking algorithm was used to vary source angle, and the minimum audible angle (MAA), the smallest angle at which right-left discrimination performance is better than chance, was estimated. All three groups participated in Experiment 1. In Experiment 2 source angles were fixed at ±50 degrees, and performance was evaluated by computing the number of SDs above chance. Children in the UCI and BICI groups participated in Experiment 2. RESULTS: : In Experiment 1, when stimulus intensity was roved by 8 dB, MAA thresholds were 3.3 degrees to 30.2 degrees (mean = 14.5 degrees) and 5.7 degrees to 69.6 degrees (mean = 30.9 degrees) in the NH group and in the BICI group, respectively. When the intensity level was fixed for the BICI group, performance did not improve. Within the BICI group, 5 out of 27 children obtained MAA thresholds within one SD of their peers who have NH; all five had >12 months of bilateral listening experience. In Experiment 2, BICIs provided some advantages when the intensity level was fixed. First, the BICI group outperformed the UCI group. Second, children in the BICI group who repeated the task with their 1st CI alone had statistically significantly better performance when using both devices. In addition, when intensity roving was introduced, a larger percentage of children who had 12 or more months of BICI experience continued to perform above chance than children who had <12 months of BICI experience. Taken together, the results suggest that children with BICIs have spatial acuity that is better than when using their first CI alone and than that of their peers who use UCIs. In addition, longer durations of BICI use tend to result in better performance, although this cannot be generalized to all participants. CONCLUSION: : This report is consistent with a growing body of evidence that spatial-hearing skills can emerge in young children who use BICIs. The observation that these skills are not concomitantly emerging in age- and experience-matched children who use UCIs suggests that BICIs provide cues that are necessary for these spatial-hearing skills that UCIs do not provide.

Sound localization skills in children who use bilateral cochlear implants and in children with normal acoustic hearing.

OBJECTIVES: To measure sound source localization in children who have sequential bilateral cochlear implants (BICIs); to determine whether localization accuracy correlates with performance on a right-left discrimination task (i.e., spatial acuity); to determine whether there is a measurable bilateral benefit on a sound source identification task (i.e., localization accuracy) by comparing performance under bilateral and unilateral listening conditions; and to determine whether sound source localization continues to improve with longer durations of bilateral experience. DESIGN: Two groups of children participated in this study: a group of 21 children who received BICIs in sequential procedures (5 to 14 years) and a group of 7 typically developing children with normal acoustic hearing (5 years). Testing was conducted in a large sound-treated booth with loudspeakers positioned on a horizontal arc with a radius of 1.2 m. Children participated in two experiments that assessed spatial hearing skills. Spatial hearing acuity was assessed with a discrimination task in which listeners determined whether a sound source was presented on the right or left side of center; the smallest angle at which performance on this task was reliably above chance is the minimum audible angle. Sound localization accuracy was assessed with a sound source identification task in which children identified the perceived position of the sound source from a multiloudspeaker array (7 or 15); errors are quantified using the root mean square (RMS) error. RESULTS: Sound localization accuracy was highly variable among the children with BICIs, with RMS errors ranging from 19 to 56 degrees . Performance of the normal hearing group, with RMS errors ranging from 9 to 29 degrees was significantly better. Within the BICI group, in 11 of 21 children, RMS errors were smaller in the bilateral versus unilateral listening condition, indicating bilateral benefit. There was a significant correlation between spatial acuity and sound localization accuracy (R = 0.68, p < 0.01), suggesting that children who achieve small RMS errors tend to have the smallest minimum audible angles. Although there was large intersubject variability, testing of 11 children in the BICI group at two sequential visits revealed a subset of children who show improvement in spatial hearing skills over time. CONCLUSIONS: A subset of children who use sequential BICIs can acquire sound localization abilities, even after long intervals between activation of hearing in the first- and second-implanted ears. This suggests that children with activation of the second implant later in life may be capable of developing spatial hearing abilities. The large variability in performance among the children with BICIs suggests that maturation of sound localization abilities in children with BICIs may be dependent on various individual subject factors such as age of implantation and chronological age.

Spoken word recognition in toddlers who use cochlear implants.

PURPOSE: The purpose of this study was to assess the time course of spoken word recognition in 2-year-old children who use cochlear implants (CIs) in quiet and in the presence of speech competitors. METHOD: Children who use CIs and age-matched peers with normal acoustic hearing listened to familiar auditory labels, in quiet or in the presence of speech competitors, while their eye movements to target objects were digitally recorded. Word recognition performance was quantified by measuring each child's reaction time (i.e., the latency between the spoken auditory label and the first look at the target object) and accuracy (i.e., the amount of time that children looked at target objects within 367 ms to 2,000 ms after the label onset). RESULTS: Children with CIs were less accurate and took longer to fixate target objects than did age-matched children without hearing loss. Both groups of children showed reduced performance in the presence of the speech competitors, although many children continued to recognize labels at above-chance levels. CONCLUSION: The results suggest that the unique auditory experience of young CI users slows the time course of spoken word recognition abilities. In addition, real-world listening environments may slow language processing in young language learners, regardless of their hearing status.

Regulation of persistent Na current by interactions between beta subunits of voltage-gated Na channels.

The beta subunits of voltage-gated Na channels (Scnxb) regulate the gating of pore-forming alpha subunits, as well as their trafficking and localization. In heterologous expression systems, beta1, beta2, and beta3 subunits influence inactivation and persistent current in different ways. To test how the beta4 protein regulates Na channel gating, we transfected beta4 into HEK (human embryonic kidney) cells stably expressing Na(V)1.1. Unlike a free peptide with a sequence from the beta4 cytoplasmic domain, the full-length beta4 protein did not block open channels. Instead, beta4 expression favored open states by shifting activation curves negative, decreasing the slope of the inactivation curve, and increasing the percentage of noninactivating current. Consequently, persistent current tripled in amplitude. Expression of beta1 or chimeric subunits including the beta1 extracellular domain, however, favored inactivation. Coexpressing Na(V)1.1 and beta4 with beta1 produced tiny persistent currents, indicating that beta1 overcomes the effects of beta4 in heterotrimeric channels. In contrast, beta1(C121W), which contains an extracellular epilepsy-associated mutation, did not counteract the destabilization of inactivation by beta4 and also required unusually large depolarizations for channel opening. In cultured hippocampal neurons transfected with beta4, persistent current was slightly but significantly increased. Moreover, in beta4-expressing neurons from Scn1b and Scn1b/Scn2b null mice, entry into inactivated states was slowed. These data suggest that beta1 and beta4 have antagonistic roles, the former favoring inactivation, and the latter favoring activation. Because increased Na channel availability may facilitate action potential firing, these results suggest a mechanism for seizure susceptibility of both mice and humans with disrupted beta1 subunits.

Using the observer-based psychophysical procedure to assess localization acuity in toddlers who use bilateral cochlear implants.

HYPOTHESIS: Localization acuity will emerge in deaf children who receive bilateral cochlear implants (BI-CIs) before the age of 3 years but not in age-matched children who use a single device. BACKGROUND: There is a growing clinical trend in which infants with severe-to-profound sensorineural hearing loss are receiving BI-CIs by 3 years. Although there is general agreement that better communicative and educational outcomes are achieved when the first implant is provided at a young age, there are few behavioral data showing the functional benefits of providing infants with BI-CIs. One potential benefit of BI-CIs is improved localization acuity, which develops within the first few years of life. METHODS: Two groups of children with chronological ages ranging from 26 to 36 months participated: 1) children with normal hearing (n = 8) and 2) children with severe-to-profound sensorineural hearing loss (n = 18). Of the children who are deaf, 10 used BI-CIs, and 8 used unilateral cochlear implants. Localization acuity was measured with a single interval 2-alternative-forced choice right/left discrimination task, and minimum audible angles were computed at a performance level of 80% correct. Behavioral data were collected using the observer-based psychophysical procedure. RESULTS: Preliminary results show that the observer-based psychophysical procedure is a feasible method to measure localization acuity in children with normal hearing and in deaf children with cochlear implants and that localization acuity is emerging in toddlers with BI-CIs but not yet in toddlers with unilateral cochlear implants. CONCLUSION: These data are among the first to show localization acuity in young children who use BI-CIs.