Preschool speech articulation and nonword repetition abilities may help predict eventual recovery or persistence of stuttering

Lower nonword syllable sequence repetition accuracy in adults who stutter is related to differences in audio-motor oscillations

OBJECTIVE

The goal of this study was to use independent component analysis (ICA) of high-density electroencephalography (EEG) to investigate whether differences in audio-motor neural oscillations are related to nonword syllable repetition accuracy in a group of adults who stutter compared to typically fluent speakers.

METHODS

EEG was recorded using 128 channels from 23 typically fluent speakers and 23 adults who stutter matched for age, sex, and handedness. EEG was recorded during delayed, 2 and 4 bilabial nonword syllable repetition conditions. Scalp-topography, dipole source estimates, and power spectral density (PSD) were computed for each independent component (IC) and used to cluster similar ICs across participants. Event-related spectral perturbations (ERSPs) were computed for each IC cluster to examine changes over time in the repetition conditions and to examine how dynamic changes in ERSPs are related to syllable repetition accuracy.

RESULTS

Findings indicated significantly lower accuracy on a measure of percentage correct trials in the AWS group and for a normalized measure of syllable load performance across conditions. Analysis of ERSPs revealed significantly lower alpha/beta ERD in left and right μ ICs and in left and right posterior temporal lobe α ICs in AWS compared to TFS (CC p < 0.05). Pearson correlations with %CT for frequency across time showed strong relationships with accuracy (FWE<0.05) during maintenance in the TFS group and during execution in the AWS group.

CONCLUSIONS

Findings implicate lower alpha/beta ERD (8-30 Hz) during syllable encoding over posterior temporal ICs and execution in left temporal/sensorimotor components. Strong correlations with accuracy and interindividual differences in ∼6-8 Hz ERSPs during execution implicate differences in motor and auditory-sensory monitoring during syllable sequence execution in AWS.

Knowns and unknowns about the neurobiology of stuttering

Stuttering occurs in early childhood during a dynamic phase of brain and behavioral development. The latest studies examining children at ages close to this critical developmental period have identified early brain alterations that are most likely linked to stuttering, while spontaneous recovery appears related to increased inter-area connectivity. By contrast, therapy-driven improvement in adults is associated with a functional reorganization within and beyond the speech network. The etiology of stuttering, however, remains enigmatic. This Unsolved Mystery highlights critical questions and points to neuroimaging findings that could inspire future research to uncover how genetics, interacting neural hierarchies, social context, and reward circuitry contribute to the many facets of stuttering.

Differences in auditory verbal working memory between adults who do and do not stutter on an N-back task

PURPOSE

The purpose of this study was to investigate auditory verbal working memory in adults who do (AWS) and do not (AWNS) stutter using a highly demanding linguistic N-back task.

METHODS

Fifteen AWS and 15 AWNS matched in age, gender and educational level were asked to hear series of words and respond by pressing a "yes" button if the word they just heard was the same as the word one, two, or three trials back. Words were either phonologically similar (i.e., Phonological Linguistic Condition) or phonologically dissimilar (i.e., Neutral Linguistic Condition). Accuracy and false alarms rates as well as reaction time on correct target trials, missed target trials and false alarms were collected and analyzed.

RESULTS

Differences were not found between AWS and AWNS in accuracy. Both groups were more accurate and significantly faster in 1- followed by 2- followed by 3-back trials. However, AWS were significantly slower than AWNS in the 2-back level, regardless of linguistic condition. Furthermore, AWS demonstrated more false alarms compared to AWNS.

CONCLUSION

Results revealed differences in auditory verbal working memory and interference control between AWS and AWNS when processing highly linguistically demanding stimuli.

Brain developmental trajectories associated with childhood stuttering persistence and recovery

Stuttering is a neurodevelopmental disorder affecting 5-8 % of preschool-age children, continuing into adulthood in 1 % of the population. The neural mechanisms underlying persistence and recovery from stuttering remain unclear and little information exists on neurodevelopmental anomalies in children who stutter (CWS) during preschool age, when stuttering symptoms typically first emerge. Here we present findings from the largest longitudinal study of childhood stuttering to date, comparing children with persistent stuttering (pCWS) and those who later recovered from stuttering (rCWS) with age-matched fluent peers, to examine the developmental trajectories of both gray matter volume (GMV) and white matter volume (WMV) using voxel-based morphometry. A total of 470 MRI scans were analyzed from 95 CWS (72 pCWS and 23 rCWS) and 95 fluent peers between 3 and 12 years of age. We examined overall group and group by age interactions in GMV and WMV in preschool age (3-5 years old) and school age (6-12 years old) CWS and controls, controlling for sex, IQ, intracranial volume, and socioeconomic status. The results provide broad support for a possible basal ganglia-thalamocortical (BGTC) network deficit starting in the earliest phases of the disorder and point to normalization or compensation of earlier occurring structural changes associated with stuttering recovery.

A Preliminary Study of Speech Rhythm Differences as Markers of Stuttering Persistence in Preschool-Age Children

PURPOSE

The purpose of this study was twofold: (a) to determine whether there are speech rhythm differences between preschool-age children who stutter that were eventually diagnosed as persisting (CWS-Per) or recovered (CWS-Rec) and children who do not stutter (CWNS), using empirical spectral analysis and empirical mode decomposition of the speech amplitude envelope, and (b) to determine whether speech rhythm characteristics close to onset are predictive of later persistence.

METHOD

Fifty children (3-4 years of age) participated in the study. Approximately 2-2.5 years after the experimental testing took place, children were assigned to the following groups: CWS-Per (nine boys, one girl), CWS-Rec (18 boys, two girls), and CWNS (18 boys, two girls). All children produced a narrative based on a text-free storybook. From the audio recordings of these narratives, fluent utterances were selected for each child from which seven envelope-based measures were extracted. Group-based differences on each measure as well as predictive analyses were conducted to identify measures that discriminate CWS-Per versus CWS-Rec.

RESULTS

CWS-Per were found to have a relatively higher degree of power in suprasyllabic oscillations and greater variability in the timing of syllabic rhythms especially for longer utterances. A logistic regression model using two speech rhythm measures was able to discriminate the eventual outcome of recovery versus persistence, with 80% sensitivity and 75% specificity.

CONCLUSION

Findings suggest that envelope-based speech rhythm measures are a promising approach to assess speech rhythm differences in developmental stuttering, and its potential for identification of children at risk of developing persistent stuttering should be investigated further.

Linguistic factors and stuttering in Nepali speaking adults who stutter

This study aimed to determine the effect of phonological and morphological factors on the dysfluencies of Nepali-speaking adults who stutter. Eighteen Nepali-speaking adult speakers with mild to very severe developmental stuttering were recruited. The spontaneous speech sample was audio-video recorded and transcribed through orthographic transcription. A total of 350 syllables were analysed to calculate stuttering frequency. Phoneme position, phoneme category, and word length were considered as the phonological factors and word-class as morphological factors. The percentage of stuttering for each of these variables was computed. The study's outcome displayed a significant effect of phoneme position and word length but no effect of phoneme category. Significantly greater stuttering was noticed in the word-initial position and longer words compared to word-medial and shorter words, respectively. In morphological factors, content words and content-function words had a greater stuttering rate than function words. This study showed a significant effect of phoneme position, word length, and grammatical class on the frequency of dysfluency in Nepali-speaking adults who stutter but no effect of phoneme category. The phonetic complexity of these variables may lead to an increase in motor planning demand resulting in more stuttering.

Individual differences in attentional control predict working memory capacity in adults who stutter

PURPOSE

Prior research has suggested that people who stutter exhibit differences in some working memory tasks, particularly when more phonologically complex stimuli are used. This study aimed to further specify working memory differences in adults who stutter by not only accounting for linguistic demands of the stimuli but also individual differences in attentional control and experimental influences, such as concomitant processing requirements.

METHOD

This study included 40 adults who stutter and 42 adults who do not stutter who completed the Attention Network Test (ANT; Fan et al., 2002) and three complex span working memory tasks: the Operation Span (OSPAN), Rotation Span, and Symmetry Span (Draheim et al., 2018; Foster et al., 2015; Unsworth et al., 2005, 2009). All complex span tasks were dual-tasks and varied in linguistic content in task stimuli.

RESULTS

Working memory capacities demonstrated by adults who stutter paralleled the hierarchy of linguistic content across the three complex span tasks, with statistically significant between-group differences in working memory capacity apparent in the task with the highest linguistic demand (i.e., OSPAN). Individual differences in attentional control in adults who stutter also significantly predicted working memory capacity on the OSPAN.

DISCUSSION

Findings from this study extend existing working memory research in stuttering by showing that: (1) significant working memory differences are present between adults who stutter and adults who do not stutter even using relatively simple linguistic stimuli in dual-task working memory conditions; (2) adults who stutter with stronger executive control of attention demonstrate working memory capacity more comparable to adults who do not stutter on the OSPAN compared to adults who stutter with lower executive control of attention.

Differences in implicit motor learning between adults who do and do not stutter

Implicit learning allows us to acquire complex motor skills through repeated exposure to sensory cues and repetition of motor behaviours, without awareness or effort. Implicit learning is also critical to the incremental fine-tuning of the perceptual-motor system. To understand how implicit learning and associated domain-general learning processes may contribute to motor learning differences in people who stutter, we investigated implicit finger-sequencing skills in adults who do (AWS) and do not stutter (ANS) on an Alternating Serial Reaction Time task. Our results demonstrated that, while all participants showed evidence of significant sequence-specific learning in their speed of performance, male AWS were slower and made fewer sequence-specific learning gains than their ANS counterparts. Although there were no learning gains evident in accuracy of performance, AWS performed the implicit learning task more accurately than ANS, overall. These findings may have implications for sex-based differences in the experience of developmental stuttering, for the successful acquisition of complex motor skills during development by individuals who stutter, and for the updating and automatization of speech motor plans during the therapeutic process.

Error Characteristics Lend Specificity to Nonword Repetition Performance in Children Who Stutter With and Without Concomitant Disorders

PURPOSE

In our earlier study, we found that overall accuracy on nonword repetition (NWR) lacked the specificity to differentiate among groups of children who stutter (CWS) with and without concomitant speech sound and/or language disorders and children who do not stutter (CWNS). The aim of this study was to determine whether NWR error characteristics distinguish these groups of children with different speech sound production and language abilities yielding insight into the deficits underlying poorer performance.

METHOD

Participants were 141 children (88 CWS, 53 CWNS). CWS were divided into subgroups based on the presence or absence of concomitant speech sound and language disorders. Children completed an NWR task composed of one- to four-syllable nonwords. Error types included omissions, substitutions, and migrations. Error location was documented across the syllables of the longest, four-syllable nonwords and within each syllable (onset, nucleus, and coda) for all nonwords.

RESULTS

We found that error patterns characterized groups' NWR performance. Specifically, CWS groups made more errors on syllable onsets, more errors on the first and fourth syllable of the four-syllable nonwords, and more substitution errors than CWNS. CWS with concomitant speech sound and/or language disorders made more omission errors than CWNS and CWS with typical speech sound and language abilities. CWS with both a speech sound and language disorder made more migration errors than all other groups.

CONCLUSIONS

Using a data-driven framework derived from prior empirical investigations of NWR errors, this study demonstrated that error characteristics enhance the specificity of NWR by distinguishing groups of CWS with and without concomitant speech sound and language deficits. These error patterns also provide a window into the processes underlying NWR performance in CWS.

Treating Concomitant Language and/or Phonology Impairment in Children Who Stutter

Stuttering can co-occur with phonological and/or language impairment in a nontrivial number of children. This article provides a framework for addressing concomitant phonology/language impairment and stuttering through the application of the World Health Organization's International Classification of Functioning, Disability and Health (ICF) framework. Described is a multifactorial approach to understanding stuttering, the application of the ICF to treating children who stutter with concomitant disorders, and models for structuring-related therapy. A case study is explored to illustrate this process and includes a sample treatment plan with goals, short-term objectives, and sample activities.

Nonword Repetition Performance Differentiates Children Who Stutter With and Without Concomitant Speech Sound and Developmental Language Disorders

PURPOSE

The aim of this study was to examine how nonword repetition (NWR) performance may be impacted by the presence of concomitant speech and language disorders in young children who stutter (CWS).

METHOD

One hundred forty-one children (88 CWS and 53 children who do not stutter [CWNS]) participated. CWS were divided into groups based on the presence of speech sound and/or language disorder or typical speech sound production and language abilities. NWR abilities were measured using stimuli composed of one- to four-syllable nonwords.

RESULTS

CWS with typical speech and language and CWNS had higher accuracy scores than CWS with concomitant speech and language disorders. We found no difference in accuracy scores between CWNS and CWS with typical speech and language abilities, nor did we find differences between CWS with speech sound disorder and CWS with both speech sound and language disorders. Accuracy decreased as nonword length increased for all groups.

CONCLUSIONS

We found that the presence of a concomitant speech and language disorder was a driving factor behind poorer NWR performance in CWS. Accuracy scores differentiated CWS with concomitant disorders from CWS with typical speech and language but not CWS with typical speech and language from CWNS. Considering the speech and language abilities of CWS helped clarify poorer NWR performance and enhances generalizability to the population that exists clinically.

Predicting Persistent Developmental Stuttering Using a Cumulative Risk Approach

PURPOSE

The purpose of this study was to explore how well a cumulative risk approach, based on empirically supported predictive factors, predicts whether a young child who stutters is likely to develop persistent developmental stuttering. In a cumulative risk approach, the number of predictive factors indicating a child is at risk to develop persistent stuttering is evaluated, and a greater number of indicators of risk are hypothesized to confer greater risk of persistent stuttering.

METHOD

We combined extant data on 3- to 5-year-old children who stutter from two longitudinal studies to identify cutoff values for continuous predictive factors (e.g., speech and language skills, age at onset, time since onset, stuttering frequency) and, in combination with binary predictors (e.g., sex, family history of stuttering), used all-subsets regression and receiver operating characteristic curves to compare the predictive validity of different combinations of 10 risk factors. The optimal combination of predictive factors and the odds of a child developing persistent stuttering based on an increasing number of factors were calculated.

RESULTS

Based on 67 children who stutter (i.e., 44 persisting and 23 recovered) with relatively strong speech-language skills, the predictive factor model that yielded the best predictive validity was based on time since onset (≥ 19 months), speech sound skills (≤ 115 standard score), expressive language skills (≤ 106 standard score), and stuttering severity (≥ 17 Stuttering Severity Instrument total score). When the presence of at least two predictive factors was used to confer elevated risk to develop persistent stuttering, the model yielded 93% sensitivity and 65% specificity. As a child presented with a greater number of these four risk factors, the odds for persistent stuttering increased.

CONCLUSIONS

Findings support the use of a cumulative risk approach and the predictive utility of assessing multiple domains when evaluating a child's risk of developing persistent stuttering. Clinical implications and future directions are discussed.

Linguistic aspects of stuttering: research updates on the language-fluency interface

PURPOSE

Although commonly defined as a speech disorder, stuttering interacts with the language production system in important ways. Our purpose is to summarize research findings on linguistic variables that influence stuttering assessment and treatment.

METHOD AND RESULTS

Numerous topics are summarized. First, we review research that has examined linguistic features that increase stuttering frequency and influence where it occurs. Second, we tackle the question of whether or not persons who stutter exhibit subtle language differences or deficits. Next, we explore language factors that appear to influence recovery from early stuttering in children. The final topic discusses the unique challenges inherent in differentially diagnosing stuttering in bilingual children. Clinical implications for each topic are discussed.

DISCUSSION

The article concludes with a discussion of the unique differences in the integration of language and speech demands by people who stutter, when compared to people who are typically fluent, and their clinical ramifications.

Exploring Relationships Among Risk Factors for Persistence in Early Childhood Stuttering

Purpose The purpose of this study is to investigate how epidemiological and clinical factors collectively predict whether a preschooler who is stuttering will persist or recover and to provide guidance on how clinicians can use these factors to evaluate a child's risk for stuttering persistence. Method We collected epidemiological and clinical measures from 52 preschoolers (M = 54.4 months, SD = 6.7 months; 38 boys and 14 girls) diagnosed as stuttering. We then followed these children longitudinally to document whether they eventually recovered or persisted in stuttering. Risk factors found to be significantly associated with stuttering persistence were used to build single and multiple variable predictive statistical models. Finally, we assessed each model's prediction capabilities by recording how accurate a model was in predicting a child's stuttering outcome-persisting or recovered. Results We found that a positive family history of stuttering, poorer performance on a standardized articulation/phonological assessment, higher frequency of stuttering-like disfluencies during spontaneous speech, and lower accuracy on a nonword repetition task were all significantly associated with an increased probability of persistence. The interaction between family history of stuttering and nonword repetition performance was also significant. The full multiple regression model incorporating all these risk factors resulted in the best fitting model with the highest predictive accuracy and lowest error rate. Conclusions For the first time, we show how multiple risk factors collectively predict the probability of stuttering persistence in 3- to 5-year-old preschool children who stutter. Using the full combination of risk factors to assess preschoolers who stutter yielded more accurate predictions of persistence compared to sparser models. A better understanding of the factors that underlie stuttering persistence will yield insight into the underpinnings of chronic stuttering and will help identify etiological targets for novel treatment approaches.

Predictive factors for persistence and recovery of stuttering in children: A systematic review

PURPOSE

The purpose of this study was to systematically review the available literature on various factors that can predict the persistence and recovery of stuttering in children.

METHOD

An electronic search yielded a total of 35 studies, which considered 44 variables that can be potential factors for predicting persistence and recovery.

RESULT

Among 44 factors studied, only four factors- phonological abilities, articulatory rate, change in the pattern of disfluencies, and trend in stuttering severity over one-year post-onset were identified to be replicated predictors of recovery of the stuttering. Several factors, such as differences in the second formant transition between fluent and disfluent speech, articulatory rate measured in phones/sec, etc., were observed to predict the future course of stuttering. However, these factors lack replicated evidence as predictors.

CONCLUSION

There is clear support only for limited factors as reliable predictors. Also, it is observed to be too early to conclude on several replicated factors due to differences in the age group of participants, participant sample size, and the differences in tools used in research that lead to mixed findings as a predictive factor. Hence there is a need for systematic and replicated testing of the factors identified before initiating their use for clinical purposes.

Neuroimaging of the Syllable Repetition Task in Children With Residual Speech Sound Disorder

Purpose This study investigated phonological and speech motor neural networks in children with residual speech sound disorder (RSSD) during an overt Syllable Repetition Task (SRT). Method Sixteen children with RSSD with /ɹ/ errors (6F [female]; ages 8;0-12;6 [years;months]) and 16 children with typically developing speech (TD; 8F; ages 8;5-13;7) completed a functional magnetic resonance imaging experiment. Children performed the SRT ("SRT-Early Sounds") with the phonemes /b, d, m, n, ɑ/ and an adapted version ("SRT-Late Sounds") with the phonemes /ɹ, s, l, tʃ, ɑ/. We compared the functional activation and transcribed production accuracy of the RSSD and TD groups during both conditions. Expected errors were not scored as inaccurate. Results No between-group or within-group differences in repetition accuracy were found on the SRT-Early Sounds or SRT-Late Sounds tasks at any syllable sequence length. On a first-level analysis of the tasks, the TD group showed expected patterns of activation for both the SRT-Early Sounds and SRT-Late Sounds, including activation in the left primary motor cortex, left premotor cortex, bilateral anterior cingulate, bilateral primary auditory cortex, bilateral superior temporal gyrus, and bilateral insula. The RSSD group showed similar activation when correcting for multiple comparisons. In further exploratory analyses, we observed the following subthreshold patterns: (a) On the SRT-Early Sounds, greater activation was found in the left premotor cortex for the RSSD group, while greater activation was found in the left cerebellum for the TD group; (b) on the SRT-Late Sounds, a small area of greater activation was found in the right cerebellum for the RSSD group. No within-group functional differences were observed (SRT-Early Sounds vs. SRT-Late Sounds) for either group. Conclusions Performance was similar between groups, and likewise, we found that functional activation did not differ. Observed functional differences in previous studies may reflect differences in task performance, rather than fundamental differences in neural mechanisms for syllable repetition.

A comparison of the performance of Persian speaking children who do and do not stutter on three nonwords repetition tasks

PURPOSE

The purpose of the study was to examine the performance of Persian speaking children who stutter (CWS) and children who do not stutter (CWNS) on three nonword repetition tasks, while also focusing on which task and scoring method best differentiates the two groups of children.

METHOD

Thirty CWS and 30 CWNS between the ages of 5;0 to 6;6 completed three nonword repetition tasks that varied in complexity. Each task was scored using two methods: nonwords correct and phonemes correct. Between-group differences in performance on each task were examined, along with disfluencies for CWS and the task and scoring method that best differentiated the CWS and CWNS.

RESULTS

The findings revealed that, across all three nonword repetition tasks, the CWS consistently produced fewer nonwords correct and phonemes correct than the CWNS group at virtually all syllable lengths. The CWS produced more disfluencies on longer nonwords than shorter nonwords in all three nonword repetition tasks. The nonword repetition task with lower wordlikeness and more phonologically complex items best differentiated the two groups of children. Findings further revealed that discriminative accuracy was highest for scoring based on the number of phonemes produced correctly.

CONCLUSION

Findings provide further evidence to suggest that CWS may have difficulty with phonological working memory and/or phonological processing.

Do dyslexia and stuttering share a processing deficit?

This study assessed the prevalence of childhood stuttering in adults with dyslexia (AWD) and the prevalence of dyslexia in adults who stutter (AWS). In addition, the linguistic profiles of 50 AWD, 30 AWS and 84 neurotypical adults were measured. We found that 17 out of 50 AWD (34 %) reported stuttering during childhood compared to 1 % of the neurotypical population. This was moderated by the severity of dyslexia: People with mild dyslexia showed a lower prevalence rate (15 %) of childhood stuttering than those with severe dyslexia (47 %). In addition, we observed that 50 % of the AWS (n = 30) fulfilled the diagnostic criteria of dyslexia, even though they had never been diagnosed as dyslexic. Compared to neurotypical adults, phonological working memory, awareness, and retrieval were similarly reduced in AWS and AWD. The findings supports the view that stuttering and dyslexia may share a phonological deficit.

Visual exogenous and endogenous attention and visual memory in preschool children who stutter

PURPOSE

Attention develops gradually from infancy to the preschool years and beyond. Exogenous attention, consisting of automatic responses to salient stimuli, develops in infancy, whereas endogenous attention, or voluntary attention, begins to develop later, in the preschool years. The purpose of this study was to examine (a) exogenous and endogenous attention in young children who stutter (CWS) and children who do not stutter (CWNS) through two conditions of a visual sustained selective attention task, and (b) visual short-term memory (STM) between groups within the context of this task.

METHOD

42 CWS and 42 CWNS, ages 3;0-5;5 (years;months), were pair-matched in age, gender (31 males, 11 females per group), and socioeconomic status. Children completed a visual tracking task (Track-It Task; Fisher et al., 2013) requiring sustained selective attention and engaging exogenous and endogenous processes. Following each item, children were asked to recall the item they had tracked, as a memory check.

RESULTS

The CWS group demonstrated significantly less accuracy in overall tracking and visual memory for the tracked stimuli, compared to the CWNS group. Across groups, the children performed better in sustained selective attention when the target stimuli were more salient (the condition tapping both exogenous and endogenous attention) than when stimuli were less so (the condition tapping primarily endogenous processes).

CONCLUSIONS

Relative to peers, preschool-age CWS, as a group, display weaknesses in visual sustained selective attention and visual STM.

Associations between stuttering, comorbid conditions and executive function in children: a population-based study

Background

The aim of this study was to investigate the relationship between executive function (EF), stuttering, and comorbidity by examining children who stutter (CWS) and children who do not stutter (CWNS) with and without comorbid conditions. Data from the National Health Interview Survey were used to examine behavioral manifestations of EF, such as inattention and self-regulation, in CWS and CWNS.

Methods

The sample included 2258 CWS (girls = 638, boys = 1620), and 117,725 CWNS (girls = 57,512; boys = 60,213). EF, and the presence of stuttering and comorbid conditions were based on parent report. Descriptive statistics were used to describe the distribution of stuttering and comorbidity across group and sex. Regression analyses were to determine the effects of stuttering and comorbidity on EF, and the relationship between EF and socioemotional competence.

Results

Results point to weaker EF in CWS compared to CWNS. Also, having comorbid conditions was also associated with weaker EF. CWS with comorbidity showed the weakest EF compared to CWNS with and without comorbidity, and CWS without comorbidity. Children with stronger EF showed higher socioemotional competence. A majority (60.32%) of CWS had at least one other comorbid condition in addition to stuttering. Boys who stutter were more likely to have comorbid conditions compared to girls who stutter.

Conclusion

Present findings suggest that comorbidity is a common feature in CWS. Stuttering and comorbid conditions negatively impact EF.

Clinical Characteristics Associated With Stuttering Persistence: A Meta-Analysis

Purpose The purpose of this meta-analytic study was to identify clinical characteristics, defined as child factors that can be assessed by a speech-language pathologist as part of a routine speech-language evaluation that may differentiate children who persist in stuttering from children who eventually recover from stuttering. Clinical characteristics explored included sex, age at onset, family history of stuttering, stuttering frequency and severity, speech-language skills, and temperament. Method Studies were identified through electronic databases, journals, and reference lists of relevant reports (e.g., research articles). Eligible studies followed young children who stutter (i.e., under 6 years old) for at least 24 months, assessed a potential clinical marker at study entry, and determined talker group classification (i.e., persistent or recovered) at study completion. Sex and family history differences were estimated using risk ratios; all other differences were estimated using Hedges's g. Heterogeneity and methodological differences among studies were evaluated. Results Eleven studies (41 reports) met eligibility criteria. Persistent children were older at stuttering onset and exhibited higher frequencies of stuttering-like disfluencies, lower speech sound accuracy, and lower expressive and receptive language skills than recovered children. Males and children with a family history of stuttering were also more likely to persist. Conclusions Clinical characteristics were identified that are associated with increased risk for stuttering persistence. Future studies have the potential to translate these clinical characteristics into prognostic markers for stuttering persistence risk.

Neural Processes Underlying Nonword Rhyme Differentiate Eventual Stuttering Persistence and Recovery

Purpose Phonological skills have been associated with developmental stuttering. The current study aimed to determine whether the neural processes underlying phonology, specifically for nonword rhyming, differentiated stuttering persistence and recovery. Method Twenty-six children who stutter (CWS) and 18 children who do not stutter, aged 5 years, completed an auditory nonword rhyming task. Event-related brain potentials were elicited by prime, rhyming, and nonrhyming targets. CWS were followed longitudinally to determine eventual persistence (n = 14) or recovery (n = 12). This is a retrospective analysis of data acquired when all CWS presented as stuttering. Results CWS who eventually recovered and children who do not stutter exhibited the expected rhyme effect, with larger event-related brain potential amplitudes elicited by nonrhyme targets compared to rhyme targets. In contrast, CWS who eventually persisted exhibited a reverse rhyme effect, with larger responses to rhyme than nonrhyme targets. Conclusions These findings suggest that CWS who eventually persisted are not receiving the same benefit of phonological priming as CWS who eventually recovered for complex nonword rhyming tasks. These results indicate divergent patterns of phonological processing in young CWS who eventually persisted, especially for difficult tasks with limited semantic context, and suggest that the age of 5 years may be an important developmental period for phonology in CWS. Supplemental Material https://doi.org/10.23641/asha.12682874.

Recovery and Relapse: Perspectives From Adults Who Stutter

Purpose Recovery and relapse relating to stuttering are often defined in terms of the presence or absence of certain types of speech disfluencies as observed by clinicians and researchers. However, it is well documented that the experience of the overall stuttering condition involves more than just the production of stuttered speech disfluencies. This study sought to identify what recovery and relapse mean to people who stutter based on their own unique experiences to account for both the stuttering behaviors and the broader adverse impact of the condition. Method In this study, 228 adults who stutter participated in a mixed-methods exploration of the terms "recovery" and "relapse." Participants categorized themselves on whether they considered themselves to have recovered or experienced relapse. Data were analyzed thematically through the lens of the speaker self-categorizations to determine how adults who stutter define recovery and relapse regarding stuttering. Results Results indicate that, to adults who stutter, recovery from stuttering is associated with increases in positive affective/emotional, behavioral, and cognitive reactions to the condition and simultaneous decreases in associated negative constructs. These group-level definitions did not change as a function of whether respondents reported that they had experienced recovery or relapse themselves. Discussion Recovery or relapse from stuttering behaviors can occur independently from recovery or relapse from the broader adverse impact related to the condition, suggesting that researchers and clinicians should consider recovery and relapse as involving more than just a reduction or an increase in observable behaviors. These findings support recent research evidence further specifying the many individual phenotypes of stuttering, in that pathways to recovery and relapse can be experienced in different ways for people with different stuttering phenotype profiles.

The recovery rate of early stuttering

PURPOSE

Across studies there is great variability in reported rates of stuttering recovery. This study examined the impact that different definitions of recovery had on calculation of recovery rates and factors associated with recovery within the same sample of children.

METHOD

Speech samples and parents and child reports of their experiences of stuttering were collected from 38 children who stuttered aged 2-5 years of age (Occassion-1) and again at 9-13 years of age (Occassion-2). Four different criteria for recovery that were developed representing variations in criteria reported in previous research were applied to data from these children.

RESULTS

. The majority of the participants (82%) showed very little disfluent speech (<1% syllables stuttered) at Occasion 2. Recovery rate varied greatly depending on the criteria used, ranging from 13.2%-94.7%. Definitions ordered from least to greatest recovery that were (a) parent and clinician report no stuttering and no stuttering observed (13.2 %); (b) ≤1% syllables stuttered; severity rated at ≤1; parent, clinician, and child report recovery (55.3 %); (c) ≤1% syllables stuttered; severity rated at ≤1; parent and clinician report recovery (71.1 %); (d) <3.0 % syllables stuttered (94.7 %). Five participants were considered recovered and two were considered persistent stutters across all criteria. Different factors were associated with recovery from stuttering depending on the criterion used.

CONCLUSION

The concept of recovery from stuttering is complex and estimations of recovery rate are likely to be greatly affected by differences in definitions and measurement across studies. This has a flow-on effect in determining the factors associated with recovery from stuttering.

Neural Indices Mediating Rhyme Discrimination Differ for Some Young Children Who Stutter Regardless of Eventual Recovery or Persistence

Purpose Previous studies of neural processing of rhyme discrimination in 7- to 8-year-old children who stutter (CWS) distinguished children who had recovered, children who had persisted, and children who did not stutter (CWNS; Mohan & Weber, 2015). Here, we investigate neural processing mediating rhyme discrimination for early acquired real words in younger CWS and CWNS (4;1-6;0 years;months), when rhyming abilities are newly emerging, to examine possible relationships to eventual recovery (CWS-eRec) and persistence in stuttering (CWS-ePer). Method Children performed a rhyme discrimination task while their event-related brain potentials were recorded. CWNS, CWS-eRec, and CWS-ePer had similar speech and language abilities. Inclusionary criteria incorporated at least 70% accuracy for rhyme discrimination. Analyses focused on the mean amplitude of the N400 component elicited by rhyming and nonrhyming words in anterior and posterior regions of interest. Results CWNS, CWS-eRec, and CWS-ePer displayed a classic event-related potential rhyme effect for rhyme discrimination characterized by larger amplitude, posteriorly distributed N400s elicited by nonrhyming targets compared to rhyming targets. CWNS displayed a more robust anterior rhyme effect compared to the CWS groups with a larger amplitude N400 anteriorly for the rhyming targets. This effect was more consistent across individual CWNS than CWS. Conclusions The groups of CWNS, CWS-eRec, and CWS-ePer, who had all developed rhyming discrimination abilities, exhibited similar underlying neural processes mediating phonological processing of early acquired words for the classic central-parietal rhyme effect. However, individual variability of the anterior rhyme effect suggested differences in specific aspects of phonological processing for some CWS-eRec and CWS-ePer compared to CWNS.

Disfluencies and Strategies Used by People Who Stutter During a Working Memory Task

Purpose Working memory (WM) deficits are implicated in various communication disorders, including stuttering. The reading span test (RST) measures WM capacity with the dual task of reading sentences aloud and remembering target words. This study demonstrates a difference in strategy between people who stutter (PWS) and people who do not stutter (PWNS) in performing the RST. The impact of the effective strategy and the stuttering-like disfluencies during the RST were investigated. Method Twenty-six PWS and 24 people who do not stutter performed the RST and a simple reading aloud task. After the RST, they were asked which strategy ("imagery" or "rehearsal") they had used in order to remember the target words during the task. Results The proportion of those who used an "imagery" strategy during the RST was significantly smaller in the PWS group. However, the RST scores of those who used an "imagery" strategy were significantly higher than the RST scores of those who used a "rehearsal" strategy in both groups. The "rehearsal" users were asked to undertake one more RST with an "imagery" strategy, which resulted in an increased score for both groups. The disfluency frequency of the PWS group was significantly reduced during the RST than during the oral reading task, irrespective of the employed strategy. Conclusions PWS tended to use the less effective verbal "rehearsal" strategy during the RST. The differential effects of switching strategies on the measured WM capacity and on the disfluency rate suggest that the enhanced fluency during the RST would be mostly attributable to the reduced attention to speech motor control. Therefore, the use of the "imagery" strategy and focusing on the contents of communication, away from speech motor control, should help PWS communicate better in daily conversation.

Nonword repetition and identification skills in Kannada speaking school-aged children who do and do not stutter

PURPOSE

The present study employed nonword repetition and nonword identification tasks to explore the phonological working memory (PWM) abilities and its interaction with speech motor control in school-aged children who do and do not stutter.

METHOD

Participants were 17 children who stutter (CWS) (Age range = 7-12) and 17 age and gender-matched children who do not stutter (CWNS). For the nonword repetition task, the participants repeated sets of 2-, 3-, and 4-syllable nonwords (n = 12 per set). The participants silently identified a target nonword from a subsequent set of three nonwords (n = 12 per 2-, 3- and 4-syllable length) for the nonword identification task. The performance of CWS on the nonword repetition task was compared with the CWNS for the mean number of accurate repetitions, number of trials taken, number of accurate repetitions on initial trial, and number of fluent repetitions across the three-syllable conditions for the tasks. For the nonword identification task, the number of nonwords identified accurately by the two groups were subjected to analysis.

RESULTS

CWS were significantly less accurate on the initial production of nonwords and required significantly more number of attempts to repeat the nonword accurately. Further for the nonword identification task, CWS were significantly less accurate than CWNS in correctly identifying the target nonword.

CONCLUSIONS

The present findings suggest that, in addition to limitations in PWM capacity, an unstable speech motor control system in CWS may lead to dysfluent speech.

The Application of EEG Mu Rhythm Measures to Neurophysiological Research in Stuttering

Deficits in basal ganglia-based inhibitory and timing circuits along with sensorimotor internal modeling mechanisms are thought to underlie stuttering. However, much remains to be learned regarding the precise manner how these deficits contribute to disrupting both speech and cognitive functions in those who stutter. Herein, we examine the suitability of electroencephalographic (EEG) mu rhythms for addressing these deficits. We review some previous findings of mu rhythm activity differentiating stuttering from non-stuttering individuals and present some new preliminary findings capturing stuttering-related deficits in working memory. Mu rhythms are characterized by spectral peaks in alpha (8-13 Hz) and beta (14-25 Hz) frequency bands (mu-alpha and mu-beta). They emanate from premotor/motor regions and are influenced by basal ganglia and sensorimotor function. More specifically, alpha peaks (mu-alpha) are sensitive to basal ganglia-based inhibitory signals and sensory-to-motor feedback. Beta peaks (mu-beta) are sensitive to changes in timing and capture motor-to-sensory (i.e., forward model) projections. Observing simultaneous changes in mu-alpha and mu-beta across the time-course of specific events provides a rich window for observing neurophysiological deficits associated with stuttering in both speech and cognitive tasks and can provide a better understanding of the functional relationship between these stuttering symptoms. We review how independent component analysis (ICA) can extract mu rhythms from raw EEG signals in speech production tasks, such that changes in alpha and beta power are mapped to myogenic activity from articulators. We review findings from speech production and auditory discrimination tasks demonstrating that mu-alpha and mu-beta are highly sensitive to capturing sensorimotor and basal ganglia deficits associated with stuttering with high temporal precision. Novel findings from a non-word repetition (working memory) task are also included. They show reduced mu-alpha suppression in a stuttering group compared to a typically fluent group. Finally, we review current limitations and directions for future research.

Autonomic Nervous System Response to Speech Production in Stuttering and Normally Fluent Preschool-Age Children

Purpose We studied speech-related sympathetic nervous system arousal of preschool-age children who do (CWS) and do not stutter (CWNS) and its association with children's proclivity to experience negative emotions and children's self-reported attitudes toward speaking. Method Electrodermal activity measures were collected from 32 preschool-age children while they engaged in a picture description and a nonword repetition task. Children's proclivity to experience negative emotions was assessed with a parent report questionnaire. Children's communication attitude was assessed with a self-report questionnaire. Results CWS did not differ from CWNS in their sympathetic arousal during a picture description task. However, during a more challenging nonword repetition task, preschool-age CWS had a higher sympathetic arousal level than CWNS. Although CWS were rated by their caregivers as more fearful and prone to sadness, children's tendency to experience stronger and more frequent negative emotions was not associated with their sympathetic arousal during speaking. Lastly, although CWS had a more negative communication attitude than CWNS, it was not associated with their level of sympathetic arousal during speaking. Conclusions Our findings suggest that age-appropriate social communication tasks are not inherently more stressful for preschool-age CWS and are not associated with state-related stress or anxiety that is often reported for adults who stutter. However, speaking tasks that place a higher demand on children's cognitive-linguistic system may be more taxing and challenging to preschool CWS than CWNS, leading to a higher level of arousal.

Is there an association between age at first words and speech sound disorders among 4- to 5-year-old children? An epidemiological cross-sectional study based on parental reports

OBJECTIVE

To investigate the role of the period of emergence of the first words and its interactions with other risk factors in predicting the development of speech sound disorder (SSD) among 4- to 5-year-old children.

METHODS

After 373 children underwent otolaryngology and speech pathology examinations, their parents answered a questionnaire about potential risk factors for speech impairment. The presence of SSD was identified by a speech pathologist who administered Fanzago's Articulation Test to each child. Multivariate logistic analysis was used to explore the relationships between variables and outcomes.

RESULTS

Mean age at first words was 17.8 ± 6.5 months of life; 25.7% of patients suffered from SSD, and 3.7% from stuttering. A family history of language impairment was found in 12.9% of the sample, whereas a family history of reading difficulty was reported in only 5.4% of cases. No differences in terms of mean age (p = 0.3) or gestational age (p = 0.16) were found between children affected by SSD and those who were not. Multivariate logistic analysis revealed that male sex (p < 0.001), a family history of language impairment (p < 0.001) and stuttering (p = 0.001) were significantly associated to SSD. Age at first words did not result a predictor of speech impairment.

CONCLUSION

In contrast to male sex (p < 0.001), family history of language impairment (p < 0.001) and stuttering (p = 0.001) which resulted significantly associated to SSD, age at first words does not seem to be a predictor of SSD (p = 0.11); however, it remains a useful indicator of language delay and, when considered in association with other language milestones, can be a reason of concern for parents and caregivers about their children's developmental and speech therapy needs.

Sympathetic Nervous System Activity in Preschoolers Who Stutter

BACKGROUND

In our Dynamic Pathways, account, we hypothesized that childhood stuttering reflects an impairment in speech sensorimotor control that is conditioned by cognitive, linguistic, and emotional factors. The purpose of this study was to investigate potential differences in levels of sympathetic arousal during performance of speech and non-speech tasks between children who do and do not stutter.

METHODS

Seventy-two preschool-aged children participated in the study, 47 children who stutter (CWS; 38 boys) and 25 children who do not stutter (CWNS; 18 boys). We recorded skin conductance and blood pulse volume (BPV) signals, indices of sympathetic arousal, during higher/lower load speech tasks (structured sentence production and picture description) and non-speech tasks (jaw wagging and forceful blowing). We included a measure that reflects children's attitudes about their communication skills and a parent-report assessment of temperament.

RESULTS

We found no significant differences between preschool CWS and CWNS in phasic skin conductance response amplitude or frequency, BPV, and pulse rate for any of the experimental tasks. However, compared to CWNS, CWS had, on average, significantly higher skin conductance levels (SCL), indexing slowly changing tonic sympathetic activity, across both speech and non-speech experimental conditions. We found distinctive task-related profiles of sympathetic arousal in both groups of preschool children. Most children produced the highest levels of sympathetic arousal in the physically demanding blowing task rather than in speech, as seen in previous studies of adults. We did not find differences in temperament between the two groups of preschool children nor a relationship among behavioral indices of temperament and communication attitude and physiological measures of sympathetic arousal.

CONCLUSION

We did not find that atypically high, speech-related sympathetic arousal is a significant factor in early childhood stuttering. Rather, CWS had higher, on average, task-related tonic SCLs across speech and non-speech tasks. A relationship among behavioral measures of temperament and physiological measures of sympathetic arousal was not confirmed. Key questions for future experiments are how the typical coupling of sympathetic and speech sensorimotor systems develops over childhood and adolescence and whether task related developmental profiles follow a different course in children who continue to stutter.

Rhyme Production Strategies Distinguish Stuttering Recovery and Persistence

Purpose The primary aim of the current study was to examine the developing phonological awareness of 4- to 5-year-old children who stutter (CWS) in relation to eventual recovery (CWS-eRec) or persistance (CWS-ePer) in stuttering, accounting for the presence of typical speech (TS) production or speech sound disorder (SSD). Method In the 1st year of a 5-year longitudinal study, 37 children who do not stutter (CWNS) and 48 CWS completed a rhyme discrimination and a rhyme production task from the Phonological Awareness Test-Second Edition (Robertson & Salter, 2007). Using data from their last year of participation, CWS were classified into CWS-ePer and CWS-eRec. Each CWS group was further divided into TS and SSD groups based on speech production abilities at the time of the rhyme tasks. Accuracy on the rhyme tasks was compared. Groups were also compared on strategies used to generate correct and incorrect responses for the rhyme production task (e.g., real-word correct, nonword correct, semantic association, repeated cues). Results All groups performed similarly on the rhyme discrimination task. On the rhyme production task, CWS-ePer-SSD and CWS-eRec-SSD performed with less accuracy than CWNS, but CWS-ePer-TS, CWS-eRec-TS, and CWNS achieved similar task accuracy. On correct rhyme production trials, CWS-ePer-TS created more nonword rhymes than real-word rhymes. CWS-ePer-TS used the nonword strategy at 1.88 times the CWNS rate. CWS-eRec-TS fell between CWS-ePer-TS and CWNS in use of the nonword strategy. Conclusions Reliance on a nonword strategy for rhyme production in CWS-ePer-TS may reflect differences in underlying phonological representations and ease of phonological access to the lexicon compared to CWNS.

Effect of phonological and morphological factors on speech disfluencies of Kannada speaking preschool children who stutter

PURPOSE

Empirical investigations have revealed a strong association between linguistic factors and stuttering, specifically phonological and morphological factors. However, the effect of these factors is suggested to vary across languages owing to the differences in their linguistic structure. Further, the trend is found to vary between AWS and CWS. Literature in this regard is scarce in the Kannada language, particularly in children. Hence, the study was driven by the need to understand the effect of phonological and morphological factors on stuttering in Kannada speaking CWS.

METHOD

Spontaneous speech samples were obtained from twenty Kannada speaking preschool CWS with a confirmed diagnosis of stuttering by an experienced speech-language pathologist. The recorded samples were transcribed, and disfluencies were marked. Further, the stuttered words were analysed for phonological and morphological features. The phonological factors included were phoneme position in a word, phoneme type and word length. Morphological factors consisted of word class and word end inflectional morphology. The percentage of stuttering was calculated with respect to each of the factors mentioned above.

RESULTS

Phoneme in the initial position of a word and words beginning with consonants had a higher rate of stuttering. Word length, word class and word end inflections were found to have no significant effect on the rate of stuttering in CWS.

CONCLUSION

Overall, current findings revealed that stuttering might manifest differently across languages varying in their linguistic structures.

Language Growth Predicts Stuttering Persistence Over and Above Family History and Treatment Experience: Response to Marcotte

Purpose This response addresses comments made by Marcotte (2019) regarding our recent publication, "Preliminary Evidence That Growth in Productive Language Differentiates Childhood Stuttering Persistence and Recovery" ( Leech, Bernstein Ratner, Brown, & Weber, 2017 ). Marcotte calls into question our finding that language growth is a valid predictor of recovery from stuttering because we did not account for treatment and family history. Conclusions In response to her comments, we provide additional empirical analyses couched in a larger discussion of the difficulty of calibrating treatment and family history of stuttering. In short, we show that once treatment history and family history of stuttering are accounted for, the effect of language growth remains a significant predictor of stuttering persistence.

Impaired processing speed in categorical perception: Speech perception of children who stutter

There have been controversial debates across multiple disciplines regarding the underlying mechanism of developmental stuttering. Stuttering is often related to issues in the speech production system; however, the presence and extent of a speech perception deficit is less clear. This study aimed to investigate the speech perception of children who stutter (CWS) using the categorical perception paradigm to examine their ability to categorize different acoustic variations of speech sounds into the same or different phonemic categories. In this study, 15 CWS and 16 children who do not stutter (CWNS) completed identification and discrimination tasks involving acoustic variations of Cantonese speech sounds in three stimulus contexts: consonants (voice onset times, VOTs), lexical tones, and vowels. The results showed similar categorical perception performance in boundary position and width in the identification task and similar d' scores in the discrimination task between the CWS and CWNS groups. However, the reaction times (RTs) were slower in the CWS group compared with the CWNS group in both tasks. Moreover, the CWS group had slower RTs in identifying stimuli located across categorical boundaries compared with stimuli located away from categorical boundaries. Overall, the data implied that the phoneme representation evaluated in speech perception might be intact in CWS as revealed by similar patterns in categorical perception as those in CWNS. However, the CWS group had slower processing speeds during categorical perception, which may indicate an insufficiency in accessing the phonemic representations in a timely manner, especially when the acoustic stimuli were ambiguous.

Differences in the relation between temperament and vocabulary based on children's stuttering trajectories

PURPOSE

The purpose of this study was to assess the relation between temperament and vocabulary development for children who stutter and persist, children who stutter and recover and children who do not stutter.

METHODS

Participants, aged 3;0-4;11 at the start of the study, were followed for two years. They were classified as persisting (n = 10), recovered (n = 26), and non-stuttering (n = 24) based on multiple assessments of stuttering spaced across study participation. Groups were balanced for age and gender ratios. At each visit, participants completed the Peabody Picture Vocabulary Test, 4th edition, and the Expressive Vocabulary Test, 2nd edition; caregivers completed the Children's Behavior Questionnaire.

RESULTS

For both persisting and recovered groups, higher negative emotionality was associated with lower receptive vocabulary. These associations were both significantly more negative than the non-stuttering group's association.

CONCLUSION

These findings suggest that receptive vocabulary development is differentially linked to temperament based on a child's stuttering status. As others have speculated (Conture & Walden, 2012), it appears as though there are salient associations between temperament, speech-language development, and childhood stuttering.

Selecting Treatments and Monitoring Outcomes: The Circle of Evidence-Based Practice and Client-Centered Care in Treating a Preschool Child Who Stutters

Purpose

The purpose of the present clinical forum is to compare how 2 clinicians might select among therapy options for a preschool-aged child who presents with stuttering close to onset.

Method

I discuss approaches to full evaluation of the child's profile, advisement of evidence-based practice options open to the family, the need for monitoring of the child's response, and selection of other approaches, if the child appears nonresponsive to the 1st-line approach.

Results

Although some researchers and clinicians appear to favor endorsement of a single recommended treatment for early stuttering, I do not find this approach helpful or consistent with newer mandates for patient-centered care. I am also most comfortable recommending RESTART demands and capacities model as the 1st treatment approach, with parent consent, because its mechanism of action appears transparent and well-documented.

Conclusions

There are numerous well-supported intervention options for treating preschool children who stutter. No single therapy can possibly work for all clients. I discuss available options that I feel have sufficient evidence-based support for use with young children who stutter. I emphasize the need to consider more, not fewer, acceptable therapy options for children who do not respond positively to a selected treatment approach within a reasonable time frame.

Phonological working memory in developmental stuttering: Potential insights from the neurobiology of language and cognition

The current review examines how neurobiological models of language and cognition could shed light on the role of phonological working memory (PWM) in developmental stuttering (DS). Toward that aim, we review Baddeley's influential multicomponent model of PWM and evidence for load-dependent differences between children and adults who stutter and typically fluent speakers in nonword repetition and dual-task paradigms. We suggest that, while nonword repetition and dual-task findings implicate processes related to PWM, it is unclear from behavioral studies alone what mechanisms are involved. To address how PWM could be related to speech output in DS, a third section reviews neurobiological models of language proposing that PWM is an emergent property of cyclic sensory and motor buffers in the dorsal stream critical for speech production. We propose that anomalous sensorimotor timing could potentially interrupt both fluent speech in DS and the emergent properties of PWM. To further address the role of attention and executive function in PWM and DS, we also review neurobiological models proposing that prefrontal cortex (PFC) and basal ganglia (BG) function to facilitate working memory under distracting conditions and neuroimaging evidence implicating the PFC and BG in stuttering. Finally, we argue that cognitive-behavioral differences in nonword repetition and dual-tasks are consistent with the involvement of neurocognitive networks related to executive function and sensorimotor integration in PWM. We suggest progress in understanding the relationship between stuttering and PWM may be accomplished using high-temporal resolution electromagnetic experimental approaches.

What Are Predictors for Persistence in Childhood Stuttering?

Over the past 10 years, we (the Purdue Stuttering Project) have implemented longitudinal studies to examine factors related to persistence and recovery in early childhood stuttering. Stuttering develops essentially as an impairment in speech sensorimotor processes that is strongly influenced by dynamic interactions among motor, language, and emotional domains. Our work has assessed physiological, behavioral, and clinical features of stuttering within the motor, linguistic, and emotional domains. We describe the results of studies in which measures collected when the child was 4 to 5 years old are related to eventual stuttering status. We provide supplemental evidence of the role of known predictive factors (e.g., sex and family history of persistent stuttering). In addition, we present new evidence that early delays in basic speech motor processes (especially in boys), poor performance on a nonword repetition test, stuttering severity at the age of 4 to 5 years, and delayed or atypical functioning in central nervous system language processing networks are predictive of persistent stuttering.

Short-Term Memory, Inhibition, and Attention in Developmental Stuttering: A Meta-Analysis

PURPOSE

This study presents a meta-analytic review of differences in verbal short-term memory, inhibition, and attention between children who stutter (CWS) and children who do not stutter (CWNS).

METHOD

Electronic databases and reference sections of articles were searched for candidate studies that examined verbal short-term memory, inhibition, and attention using behavioral and/or parent report measures. Twenty-nine studies met the eligibility criteria, which included, among other things, children between the ages of 3 and 18 years and the availability of quantitative data for effect size calculations. Data were extracted, coded, and analyzed, with the magnitude of the difference between the 2 groups of children being estimated using Hedge's g (Hedges & Olkin, 1985).

RESULTS

Based on the random-effects model (Hunter & Schmidt, 2004), findings revealed that CWS scored lower than CWNS on measures of nonword repetition (Hedges' g = -0.62), particularly at lengths of 2 and 3 syllables (Hedges' g = -0.62 and - 0.50, respectively), and forward span (Hedges' g = -0.40). Analyses further revealed that the parents of CWS rated their children as having weaker inhibition (Hedges' g = -0.44) and attentional focus/persistence (Hedges' g = -0.36) skills than the parents of CWNS, but there were no significant differences between CWS and CWNS in behavioral measures of inhibition and attention.

CONCLUSION

The present findings were taken to suggest that cognitive processes are important variables associated with developmental stuttering.

The effect of emotion on articulation rate in persistence and recovery of childhood stuttering

PURPOSE

This study investigated the possible association of emotional processes and articulation rate in pre-school age children who stutter and persist (persisting), children who stutter and recover (recovered) and children who do not stutter (nonstuttering).

METHODS

The participants were ten persisting, ten recovered, and ten nonstuttering children between the ages of 3-5 years; who were classified as persisting, recovered, or nonstuttering approximately 2-2.5 years after the experimental testing took place. The children were exposed to three emotionally-arousing video clips (baseline, positive and negative) and produced a narrative based on a text-free storybook following each video clip. From the audio-recordings of these narratives, individual utterances were transcribed and articulation rates were calculated.

RESULTS

Results indicated that persisting children exhibited significantly slower articulation rates following the negative emotion condition, unlike recovered and nonstuttering children whose articulation rates were not affected by either of the two emotion-inducing conditions. Moreover, all stuttering children displayed faster rates during fluent compared to stuttered speech; however, the recovered children were significantly faster than the persisting children during fluent speech.

CONCLUSION

Negative emotion plays a detrimental role on the speech-motor control processes of children who persist, whereas children who eventually recover seem to exhibit a relatively more stable and mature speech-motor system. This suggests that complex interactions between speech-motor and emotional processes are at play in stuttering recovery and persistency; and articulation rates following negative emotion or during stuttered versus fluent speech might be considered as potential factors to prospectively predict persistence and recovery from stuttering.

Executive function and childhood stuttering: Parent ratings and evidence from a behavioral task

PURPOSE

The purpose of this study was to examine the executive function (EF) abilities of preschool children who do (CWS) and do not stutter (CWNS) using a parent-report questionnaire and a behavioral task.

METHOD

Participants were 75 CWS and 75 CWNS between the ages of 3;0 and 5;11 (years; months). Parents rated their children's EF abilities using the Behavioral Rating Inventory of Executive Function-Preschool Version (BRIEF-P; Gioia, Espy, & Isquith, 2003). Children's ability to integrate cognitive flexibility, inhibitory control, and working memory was measured using a behavioral task, the Head-Toes-Knees-Shoulders (HTKS; Cameron Ponitz, McClelland, Matthews, & Morrison, 2009).

RESULTS

The CWS were judged by their parents as being less proficient in working memory, shift/flexibility, and overall EF than the parents of the CWNS. Children in the CWS group were also 2½ to 7 times more likely than children in the CWNS group to exhibit clinically significant difficulties with EF. Behavioral task findings revealed that 3-year old CWS performed more poorly than their peers on the HTKS. Parental ratings of executive function and working memory were significantly and moderately correlated with receptive and expressive vocabulary skills only for the CWNS group.

CONCLUSION

CWS have more difficulty with EF in everyday life and may experience early delays in their ability to integrate aspects of attention and EF compared to CWNS.

The linguistic aspects of the speech of Jordanian children who stutter

BACKGROUND

The influence of linguistic variables on moments of stuttering has been a popular area of research for several years. The purpose of this study is to assess the linguistic factors of the speech of children who stutter.

METHODS

Forty-one children who stutter (31 males, 10 females) were selected from 14 schools with age range of 6-13 years. Phonological and morphological variables were measured using spontaneous speech task, whereas syntactic variables were measured using sentence completion task.

RESULTS

Results indicated significantly that (a) inflected words (M = 50, SD = 30) are more likely to be stuttered than non-inflected words (M = 32, SD = 18) [P = 0.000], (b) stuttering occurs more on initial position of the word than medial or final position [P = 0.000], (c) higher rate of stuttering is associated with increasing length of the word [P = 0.000], (d) long sentences are more likely to be stuttered than short sentences [P = 0.000], (e) the loci of stuttering is higher in stressed syllables (M = 34, SD = 30) than unstressed syllables (M = 24, SD = 20) [p = 0.002], (f) the occurrence of stuttering is more on consonant sounds (M = 36, SD = 18) than vowel sounds (M = 25, SD = 28) [P = 0.009].

CONCLUSIONS

These results support the relationship between the linguistic factors and the frequency of stuttering which could be taken into consideration in the development of treatment protocols for children who stutter.

Children who stutter at 3 years of age: A community-based study

PURPOSE

Lack of social resources to support children who stutter may be due, in part, to the absence of epidemiological data regarding stuttering. This study investigated the proportion of three-year-old children who stutter in a city located in Hokkaido, a northern island of Japan.

METHODS

The speech of individual children was assessed as part of a routine, government-conducted health care examination for 3-year-old children. The number of children screened was 2274, or 94.4% of all children in the city. The first author participated in the health care examination, and followed up all of the children who were found to stutter.

RESULTS

At 3 years of age, 1.41% of the children exhibited stuttering; 82.8% of these children subsequently did not exhibit stuttering six months later. Boys were 1.57 times more likely to stutter than girls, but they had only 86% of the probability of reported or observed fluency seen in girls six months later. Significantly higher probability of later fluency was observed in children who exhibited normal, rather than delayed, language development at the 1.5-year health checkup preceding the 3-year health checkup.

CONCLUSION

The proportion of three-year-old children who stutter and fluency status 6 months later are reported for a large cohort of Japanese children in Hokkaido. Language skills at 1;6 year may potentially be a factor in natural recovery or persistence; because of limitations in our study design, this assumption requires additional study. This is the first preliminary study to determine the proportion of three-year-old children who stutter in a Japanese community.

Uniqueness Point Effects during Speech Planning in Adults Who Do and Do Not Stutter

BACKGROUND/AIMS

Previous studies employing a variety of tasks have demonstrated that adults who stutter (AWS) pre-sent with phonological encoding differences compared to adults who do not stutter (AWNS). The present study examined whether atypical preverbal monitoring also influenced AWS performance during one such paradigm - the silent phoneme monitoring task. Specifically, we investigated whether monitoring latencies for AWS were accelerated after the word's uniqueness point - the phoneme that isolates the word from all lexical competitors - as observed for AWNS when monitoring internal and external speech.

METHODS

Twenty adults (10 AWS, 10 AWNS) completed a silent phoneme monitoring task using stimuli which contained either (a) early uniqueness points (EUP), (b) late uniqueness points, or (c) no uniqueness point (NUP). Response latency when identifying word-final phonemes was measured.

RESULTS

AWNS exhibited the expected uniqueness point effect when monitoring internal speech; word-final phonemes were accessed more rapidly for words with EUP than NUP. In contrast, AWS did not differ in the phoneme monitoring speed. That is, AWS did not exhibit the expected uniqueness point effects.

CONCLUSION

Findings suggest that inefficient or atypical preverbal monitoring may be present in AWS and support theories that implicate the internal speech monitor as an area of deficit.

Sympathetic arousal as a marker of chronicity in childhood stuttering

PURPOSE

This study investigated whether sympathetic activity during a stressful speaking task was an early marker for stuttering chronicity.

METHOD

Participants were 9 children with persisting stuttering, 23 children who recovered, and 17 children who do not stutter. Participants performed a stress-inducing picture-naming task and skin conductance was measured across three time points.

RESULTS

Findings indicated that at the initial time point, children with persisting stuttering exhibited higher sympathetic arousal during the stressful speaking task than children whose stuttering recovered.

CONCLUSIONS

Findings are taken to suggest that sympathetic activity may be an early marker of heightened risk for chronic stuttering.

Nonword repetition in adults who stutter: The effects of stimuli stress and auditory-orthographic cues

Purpose

Adults who stutter (AWS) are less accurate in their immediate repetition of novel phonological sequences compared to adults who do not stutter (AWNS). The present study examined whether manipulation of the following two aspects of traditional nonword repetition tasks unmask distinct weaknesses in phonological working memory in AWS: (1) presentation of stimuli with less-frequent stress patterns, and (2) removal of auditory-orthographic cues immediately prior to response.

Method

Fifty-two participants (26 AWS, 26 AWNS) produced 12 bisyllabic nonwords in the presence of corresponding auditory-orthographic cues (i.e., immediate repetition task), and the absence of auditory-orthographic cues (i.e., short-term recall task). Half of each cohort (13 AWS, 13 AWNS) were exposed to the stimuli with high-frequency trochaic stress, and half (13 AWS, 13 AWNS) were exposed to identical stimuli with lower-frequency iambic stress.

Results

No differences in immediate repetition accuracy for trochaic or iambic nonwords were observed for either group. However, AWS were less accurate when recalling iambic nonwords than trochaic nonwords in the absence of auditory-orthographic cues.

Conclusions

Manipulation of two factors which may minimize phonological demand during standard nonword repetition tasks increased the number of errors in AWS compared to AWNS. These findings suggest greater vulnerability in phonological working memory in AWS, even when producing nonwords as short as two syllables.