Exploring Relationships Among Risk Factors for Persistence in Early Childhood 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.

Erasmus clinical model of the onset and development of stuttering 2.0

A clinical, evidence-based model to inform clients and their parents about the nature of stuttering is indispensable for the field. In this paper, we propose the Erasmus Clinical Model of Stuttering 2.0 for children who stutter and their parents, and adult clients. It provides an up-to-date, clinical model summary of current insights into the genetic, neurological, motoric, linguistic, sensory, temperamental, psychological and social factors (be it causal, eliciting, or maintaining) related to stuttering. First a review is presented of current insights in these factors, and of six scientific theories or models that have inspired the development of our current clinical model. Following this, we will propose the model, which has proven to be useful in clinical practice. The proposed Erasmus Clinical Model of Stuttering visualizes the onset and course of stuttering, and includes scales for stuttering severity and impact, to be completed by the (parent of) the person who stutters. The pathway of the model towards stuttering onset is based on predisposing and mediating factors. In most children with an onset of stuttering, stuttering is transient, but if stuttering continues, its severity and impact vary widely. The model includes the circle of Engel (1977), which visualizes unique interactions of relevant biological, psychological, and social factors that determine the speaker's experience of stuttering severity and its impact. Discussing these factors and their interaction with an individual client can feed into therapeutic targets. The model is supplemented by a lifeline casus.

A prospective 14-year follow-up study of the persistence and recovery of stuttering

PURPOSE

To document the trajectory of early childhood stuttering longitudinally for 14. years with a consideration on the features of overt and covert stuttering related to recovery status.

METHOD

Thirty-eight participants were observed longitudinally at three different time points: early childhood (Occasion 1), middle childhood (Occasion 2), and late adolescence (Occasion 3). Data collection involved speech samples and reports of stuttering experiences. Recovery on Occasion 3 was estimated through analysis of speech samples, parent and expert judgments, and self- judgement. Two categories of persistence were used: persistent-subjective (no observable stuttering) and persistent-objective (observable stuttering).

RESULTS

The recovery rate was 65.6%. The majority of the participants showed minimal disfluent speech with 88% showing less than 1% syllables stuttered and 97% showing less than 3% syllables stuttered in the collected speech samples. All participants classified as persistent reported covert symptoms of stuttering. No relapses in recovery were observed between Occasion 2 and Occasion 3. Late recovery was only observed for those classified as persistent-subjective on Occasion 2. About 64% of the participants showing observable stuttering (persistent-objective) on Occasion 2 showed no observable stuttering (persistent-subjective) on Occasion 3.

CONCLUSIONS

Children continue to recover from early childhood stuttering as they age.The inclusion of self-reports adds to the understanding of recovery especially concerning the covert stuttering behaviours. The presence of overt symptoms of stuttering in the speech samples of children aged 7 to 13 years seems to be associated with the likelihood of late recovery of stuttering.

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.

Dyslexia and Stuttering: An Overview of Processing Deficits and the Relationship Between Them

Stuttering and dyslexia are two processing deficits that have an impact on a person's social and academic lives, especially as they usually affect the pediatric population more than adults. Even though they affect different domains, they have similar characteristics in their pathogenesis, epidemiology, and impact on life. Both disorders represent a considerable percentage of the population worldwide and locally in Saudi Arabia, and they have similar epidemiological trends. Family history, genetic factors, early fetal and neonatal factors, and environmental factors are all identified as risk factors for both conditions. Moreover, it has been established that both diseases share a common genetic and anatomical basis, along with a mutual disruption of diadochokinetic skills. While rehabilitative techniques can be used in both conditions, stuttering could also benefit from pharmacological interventions. This review emphasizes that extensive research should be done to explore both of these conditions as they impact different areas of one's life and the relationship between them to better understand their pathophysiological origins.

Bilingualism as a risk factor for false reports of stuttering in the Early Childhood Longitudinal Study (ECLS-K:2011)

Introduction

Bilingualism has historically been claimed to be a risk factor for developmental stuttering. The Early Childhood Longitudinal Study, Kindergarten Class of 2010-11 (ECLS-K:2011) ostensibly contains evidence to test that claim.

Methods

We analyze data from monolingual and bilingual children in Kindergarten through fifth grade in the ECLS-K:2011.

Results and discussion

The prevalence, male/female ratio, and onset and recovery of reported stuttering in the ECLS are inconsistent with widely-accepted clinical reports of stuttering. We argue that the reported figures may be misleading. We discuss some factors that may inflate the reported prevalence, including a lack of awareness of the difference between stuttering vs. normal disfluencies, and the informal usage of the word "stuttering" on the part of teachers and parents to describe typical disfluencies.

Dissecting structural connectivity of the left and right inferior frontal cortex in children who stutter

Inferior frontal cortex pars opercularis (IFCop) features a distinct cerebral dominance and vast functional heterogeneity. Left and right IFCop are implicated in developmental stuttering. Weak left IFCop connections and divergent connectivity of hyperactive right IFCop regions have been related to impeded speech. Here, we reanalyzed diffusion magnetic resonance imaging data from 83 children (41 stuttering). We generated connection probability maps of functionally segregated area 44 parcels and calculated hemisphere-wise analyses of variance. Children who stutter showed reduced connectivity of executive, rostral-motor, and caudal-motor corticostriatal projections from the left IFCop. We discuss this finding in the context of tracing studies from the macaque area 44, which leads to the need to reconsider current models of speech motor control. Unlike the left, the right IFCop revealed increased connectivity of the inferior posterior ventral parcel and decreased connectivity of the posterior dorsal parcel with the anterior insula, particularly in stuttering boys. This divergent connectivity pattern in young children adds to the debate on potential core deficits in stuttering and challenges the theory that right hemisphere differences might exclusively indicate compensatory changes that evolve from lifelong exposure. Instead, early right prefrontal connectivity differences may reflect additional brain signatures of aberrant cognition-emotion-action influencing speech motor control.

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.

A study of respiratory sinus arrhythmia and stuttering persistence

INTRODUCTION

The present study investigated potential differences in respiratory sinus arrhythmia between preschool-age children with persisting stuttering, children who recovered from stuttering, and children who do not stutter.

METHODS

Participants were 10 children with persisting stuttering (persisting group), 20 children who recovered from stuttering (recovered group), and 36 children who do not stutter (non-stuttering group). Participants viewed a neutral video clip to establish a pre-arousal baseline and then viewed two emotionally-arousing video clips (positive and negative, counterbalanced). Age-appropriate speaking tasks followed each of the video clips (post-baseline, post-positive, and post-negative). Respiratory sinus arrhythmia (RSA), an index of parasympathetic nervous system activity, was measured during the video clips and subsequent speaking tasks.

RESULTS

First, the persisting group, recovered group, and non-stuttering group did not significantly differ in baseline RSA. Second, during the emotionally-arousing video clips, there was a significant group x condition interaction, with the recovered group exhibiting significantly lower RSA in the positive than negative condition, and the non-stuttering group exhibiting significantly higher RSA in the positive than negative condition. Third, in the narrative tasks, there was a significant group x condition interaction, with a greater difference in RSA between the post-baseline speaking task and the post-positive and post-negative speaking tasks for the persisting compared to the non-stuttering group. Lastly, a follow-up analysis indicated that the recovered and nonstuttering groups, compared to the persisting group, exhibited significantly greater RSA during the baseline (neutral) condition compared to the post-neutral narrative task.

CONCLUSIONS

Findings provide a physiological perspective of emotion within children who stutter and persist and children who stutter and recover. Future investigations with larger sample sizes and diverse methodologies are necessary to provide novel insights on the specific emotion-related processes that are potentially involved with persistence of stuttering in young children.

Communicative Fluency and the Experience of Stuttering: A Viewpoint

PURPOSE

Despite ambiguity in meaning and usage, "fluency" has played a central role in the understanding and treatment of developmental stuttering. The appropriateness of the term fluency in association with so-called fluency disorders, such as stuttering, has recently been questioned. The purpose of this article is to propose that fluency is best conceptualized as the efficiency of goal-directed action through cybernetic function. Spoken utterances are examples of sequences of action for the fulfillment of a hierarchy of nested and increasingly abstract social goals, including behaviors (e.g., introducing oneself) and values (e.g., being a sociable person). In contrast, some moments of speech disfluency, such as stuttering disfluencies, are inefficiencies in goal-directed action that may or may not hinder the fulfillment of higher level communicative behaviors and values, described here as communicative fluency.

CONCLUSIONS

The concept of communicative fluency refers to the continual, reliable, and upward fulfillment of increasingly abstract social goals in the form of communicative actions, behaviors, and values. This expanded conceptualization of fluency beyond simply speech production has the potential to be a useful indicator of psychosocial well-being for individuals who stutter.

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.

A Genetic Neural Net Model for the Relationship between Pre-School and Attention in Early Childhood

This paper uses an algorithm of a genetic neural network to conduct an in-depth study and analysis of the attention relationship in pre-school education of young children. In face expression images, expression features are often concentrated and distributed in some local regions, while convolutional neural networks are homogeneous for feature extraction of facial expression images. To address the problem of the nonuniform distribution of expression features, a facial expression recognition method based on the spatial domain attention mechanism is proposed. A comparison of the differences between group and grade before the intervention using a two-way multivariate ANOVA revealed a nonsignificant interaction effect with a value of 0.90 for the group-grade interaction effect and an F-value of 0.36. The group's main effect had a value of 0.90 and an F-value of 0.36, with the experimental and control groups being equal groups on multiple dependent variables. The salient features in face expression images that are more important for facial expression recognition can be selected adaptively, and relatively high weights are assigned to these salient features. Experimental results on the image library show that the introduction of a spatial domain attention mechanism can improve the average recognition accuracy of face expressions by about 1.1% and 1.0%, respectively. A hybrid domain attention mechanism-based face expression recognition method is proposed to extract important expression features from both the spatial domain and the channel domain. Experimental results on the image library show that combining the spatial domain attention mechanism and the channel domain attention mechanism can improve the average recognition accuracy by about 2.1% and 1.5%, respectively. The use of rule games was effective in developing children's sustained and selective attention; the effect of rule games on the sustained and selective attention of older boys and girls did not show significant gender differences.

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.

Contemporary Theories of Stuttering Development

The article presents a theoretical analysis of contemporary models of persistent stuttering development in children and adults at the current period of development of science. The accumulated amount of scientific knowledge suggests that stuttering has a neurological basis: it is associated with disorders in the structure and function of the brain. On this basis, there have been emerged models of stuttering that link the cause of a speech disorder with an unstable speech motor system. Theories and models of stuttering based on cognitive and language processing are likely to be useful in that they have explanatory power in relation to the mechanisms that play an important role in the production of key symptoms of stuttering. Considering that stuttering is a complex disorder, the logical result of this was the proposal of multifactorial models of impaired speech fluency. The presented overview may be useful to psychiatrists, clinical psychologists, speech therapists, teachers, and practitioners interacting with children and adults with stuttering and other speech fluency disorders.