Clinical Characteristics Associated With Stuttering Persistence: A Meta-Analysis

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.

The Association Between Stuttering Burden and Psychosocial Aspects of Life in Adults

PURPOSE

Stuttering is a speech condition that can have a major impact on a person's quality of life. This descriptive study aimed to identify subgroups of people who stutter (PWS) based on stuttering burden and to investigate differences between these subgroups on psychosocial aspects of life.

METHOD

The study included 618 adult participants who stutter. They completed a detailed survey examining stuttering symptomatology, impact of stuttering on anxiety, education and employment, experience of stuttering, and levels of depression, anxiety, and stress. A two-step cluster analytic procedure was performed to identify subgroups of PWS, based on self-report of stuttering frequency, severity, affect, and anxiety, four measures that together inform about stuttering burden.

RESULTS

We identified a high- (n = 230) and a low-burden subgroup (n = 372). The high-burden subgroup reported a significantly higher impact of stuttering on education and employment, and higher levels of general depression, anxiety, stress, and overall impact of stuttering. These participants also reported that they trialed more different stuttering therapies than those with lower burden.

CONCLUSIONS

Our results emphasize the need to be attentive to the diverse experiences and needs of PWS, rather than treating them as a homogeneous group. Our findings also stress the importance of personalized therapeutic strategies for individuals with stuttering, considering all aspects that could influence their stuttering burden. People with high-burden stuttering might, for example, have a higher need for psychological therapy to reduce stuttering-related anxiety. People with less emotional reactions but severe speech distortions may also have a moderate to high burden, but they may have a higher need for speech techniques to communicate with more ease. Future research should give more insights into the therapeutic needs of people highly burdened by their stuttering.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.25582980.

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.

The Fifth Croatia Stuttering Symposium: Part II. Natural recovery from early stuttering

PURPOSE

The Fifth Croatia Stuttering Symposium of 2022 continued the Fourth Croatia Stuttering Symposium 2019 theme of the connection between research and clinical practice. At the 2022 Symposium, there were 145 delegates from 21 countries. This paper documents the contents of the second of three Symposium modules.

METHODS

The module topic was that some children with early stuttering will recover naturally. A clinical situation was considered where a parent of a 3-year-old child asked if a clinician can predict whether their child will recover from stuttering without treatment.

RESULTS

A distinguished scholar presented a 5-minute video interpretation of research about this topic. Three master clinicians then each presented a 2-minute video demonstration of how that research might be applied in a clinical situation. Following that, the convenors moderated a discussion between the distinguished scholar, master clinicians, and delegates regarding the research and how it applies to clinical practice.

Analysis of cumulative risk predictors for persistent stuttering: family perception and amount of speech disruptions

PURPOSE

To investigate two independent variables considered as two possible predictors of cumulative risk for persistent stuttering: family perception of stuttering and amount of speech disruptions.

METHODS

Participants were 452 children, aged 3 to 11:11 years, male and female, divided into 4 groups: group 1 (SCG), composed of 158 children who presented a percentage of stuttered speech disruptions ≥ 3% and family complaint of stuttering; group 2 (SWCG), 42 children who presented percentage of stuttered speech disruptions ≥ 3% and without family complaint of stuttering; group 3 (FCG), 94 children who presented percentage of stuttered speech disruptions ≤ 2. 9% with family complaints of stuttering and group 4 (FWCG), 158 children who presented a percentage of stuttered speech disruptions ≤ 2.9 without family complaints of stuttering.

RESULTS

For the SCG group, there was a significant relationship between family complaints of stuttering and the number of speech disruptions typical of stuttering. In this group, there was a predominance of male children. For the SWCG group, there was no significant relationship between family complaints of stuttering and the number of speech disruptions. For the FCG group, there was no significant relationship between family complaints of stuttering and the number of speech disruptions. For the FWCG group, there was a significant relation between the absence of a family complaint of stuttering and the reduced number of speech disruptions.

CONCLUSION

The percentage of speech disruptions ≥ 3% is a risk indicator for persistent stuttering. The percentage of speech disruptions ≤ 2.9% associated with syllable and sound repetitions can be a risk indicator for persistent stuttering. Family complaints of syllable and sound repetitions may be a risk indicator for persistent stuttering. Family complaints of stuttering alone should not be considered an indicator of persistent stuttering.

Adult recasts as fluency-facilitators in preschoolers who stutter: Evidence from FluencyBank

Adult conversational recasts are based on child platform utterances that contain errors (e.g., Child: "Me going." Adult: "Yes, you are going"), and recasts are effective in the child language literature. For many years, adult recasts of preschoolers' stuttered utterances were surmised as fluency-facilitating, but to date, no evidence has been reported to support their efficacy. The purpose was to investigate the natural occurrence of, and the fluency-facilitating potential of, recasts produced by caregivers and clinicians/examiners in free-play interactions transcribed from audio or video recordings on FluencyBank. Forty-three participants with a median age of 38 mo (3;2) (Range=28-73 mo), including 32 boys and 11 girls were selected from five databases, and recasts which were near-imitations and simple recasts as per Weiss (2002) were identified. One database chosen was the Illinois project, to include a subgroup of persistent (n = 9) and recovered children (n = 9). In the 43 participants, significantly (p < 0.0001) fewer stutters and lower percent syllables stuttered (%SS) were observed in post-recast utterances (4%SS) as compared to post-nonrecast utterances (12.5%SS). The CWS-persistent subgroup (n = 9) did not fit the group trend of the 34 others who significantly differed in stuttering frequency post-nonrecast versus postrecast. Findings are taken to mean that adult conversational recasts of preschoolers' stuttered utterances are fluency-facilitating, and interpretations are addressed.

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.

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.

Complex response inhibition and cognitive flexibility in school-aged Cypriot-Greek-speaking children who stutter

PURPOSE

Over the last few years, research findings have suggested limitations in executive function (EF) of children who stutter (CWS) with the evidence being more consistent in studies with preschoolers (3-6  years old) than in studies with school-aged children (6-12  years old). The purpose of the current study was to assess complex response inhibition and cognitive flexibility in school-aged CWS and their non-stuttering peers.

METHODS

Participants, 19 CWS (mean age = 7.58  years, range 6.08-9.17) and 19 age-and gender-matched children who do not stutter (CWNS; mean age = 7.58  years, range 6.08-9.33), completed a visual task consisting of three task blocks. Analyses were based on response times and error percentages during the different task blocks.

RESULTS

All participants showed expected performance-costs in task block comparisons targeting complex response inhibition and cognitive flexibility. Significant group differences were found in measures of cognitive flexibility with CWS performing slower compared to CWNS (p = 0.02). Additionally, significant block × group interactions demonstrated that CWS, compared to CWNS, slowed down more (i.e., higher performance-cost) under both complex response inhibition (p = 0.049) and cognitive flexibility task conditions (p = 0.04 for no-set-shifting and p = 0.02 for set-shifting).

CONCLUSION

These results are in line with some of the previous findings in school-aged CWS and suggest that CWS present lower performance in complex response inhibition and cognitive flexibility task conditions when compared to their non-stuttering peers.

Self-reported impact of developmental stuttering across the lifespan

AIM

To examine the phenomenology of stuttering across the lifespan in the largest prospective cohort to date.

METHOD

Participants aged 7 years and older with a history of developmental stuttering were recruited. Self-reported phenotypic data were collected online including stuttering symptomatology, co-occurring phenotypes, genetic predisposition, factors associated with stuttering severity, and impact on anxiety, education, and employment.

RESULTS

A total of 987 participants (852 adults: 590 males, 262 females, mean age 49 years [SD = 17 years 10 months; range = 18-93 years] and 135 children: 97 males, 38 females, mean age 11 years 4 months [SD = 3 years; range = 7-17 years]) were recruited. Stuttering onset occurred at age 3 to 6 years in 64.0%. Blocking (73.2%) was the most frequent phenotype; 75.9% had sought stuttering therapy and 15.5% identified as having recovered. Half (49.9%) reported a family history. There was a significant negative correlation with age for both stuttering frequency and severity in adults. Most were anxious due to stuttering (90.4%) and perceived stuttering as a barrier to education and employment outcomes (80.7%).

INTERPRETATION

The frequent persistence of stuttering and the high proportion with a family history suggest that stuttering is a complex trait that does not often resolve, even with therapy. These data provide new insights into the phenotype and prognosis of stuttering, information that is critically needed to encourage the development of more effective speech therapies.

WHAT THIS PAPER ADDS

Half of the study cohort had a family history of stuttering. While 75.9% of participants had sought stuttering therapy, only 15.5% identified as having recovered. There was a significant negative correlation between age and stuttering frequency and severity in adults.

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.

Risk Factors for the Development of Persistent Stuttering: What Every Pediatrician Should Know

Early identification and adequate treatment of children who stutter is important, since it has an impact on speech development. Considering the importance of aiding pediatricians to recognize children at risk for developing persistent stuttering, the aim of the present study was to correlate speech fluency characteristics of children, whose parents reported stuttering behaviors, to the risk factors of persistent stuttering. The participants were 419 children aged 2:0 to 11:11 years, who were divided into two groups: children with stuttering complaints (CSC), composed of children whose parents reported the presence of stuttering behaviors; and children with no stuttering complaint (CNSCs), composed of children with no stuttering behaviors. Risk variables were gathered based on a questionnaire answered by parents involving the following variables: sex, presence of family history of stuttering, whether stuttering behaviors were observed for more than 12 months, whether stuttering behaviors began before 5 years of age, increased effort to speak (i.e., syllable and sound repetitions and fixed articulatory positions), negative family attitude towards the child’s speech, and negative attitude towards the child’s own speech. The diagnosis of stuttering was determined by a formal speech assessment by a pathologist (SLP). The risk analysis indicated that increased effort to speak, negative family attitude towards the child’s speech, and complaints of stuttering for more than 12 months were associated with a higher risk of stuttering in children. Therefore, when pediatricians are faced with complaints about the presence of stuttering behaviors and these factors are present, they should immediately refer the patient to an SLP for specific assessment.

How to Interpret and Evaluate a Meta-Analysis in the Field of Speech-Language Pathology: A Tutorial for Clinicians

PURPOSE

This tutorial will provide speech-language pathologists with practical considerations and pragmatic tools for interpreting and critically evaluating a meta-analysis. Meta-analysis, which is a statistical procedure that involves combining research data across multiple high-quality research studies, is often considered the highest level of research evidence. Although meta-analyses are commonly deployed in clinical research after completing a systematic review, few clinicians or clinician scientists within the field of speech-language pathology receive formal training to conduct, interpret, or assess meta-analyses to determine the effectiveness of a treatment or procedure for evidence-based practice.

CONCLUSION

Clinicians within the field of speech-language pathology may use the foundational knowledge and practical guidelines outlined in this tutorial about meta-analyses to expand their knowledge of research methods and to shape their clinical practice.

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.

Phenome risk classification enables phenotypic imputation and gene discovery in developmental stuttering

Developmental stuttering is a speech disorder characterized by disruption in the forward movement of speech. This disruption includes part-word and single-syllable repetitions, prolongations, and involuntary tension that blocks syllables and words, and the disorder has a life-time prevalence of 6-12%. Within Vanderbilt's electronic health record (EHR)-linked biorepository (BioVU), only 142 individuals out of 92,762 participants (0.15%) are identified with diagnostic ICD9/10 codes, suggesting a large portion of people who stutter do not have a record of diagnosis within the EHR. To identify individuals affected by stuttering within our EHR, we built a PheCode-driven Gini impurity-based classification and regression tree model, PheML, by using comorbidities enriched in individuals affected by stuttering as predicting features and imputing stuttering status as the outcome variable. Applying PheML in BioVU identified 9,239 genotyped affected individuals (a clinical prevalence of ∼10%) for downstream genetic analysis. Ancestry-stratified GWAS of PheML-imputed affected individuals and matched control individuals identified rs12613255, a variant near CYRIA on chromosome 2 (B = 0.323; p value = 1.31 × 10-8) in European-ancestry analysis and rs7837758 (B = 0.518; p value = 5.07 × 10-8), an intronic variant found within the ZMAT4 gene on chromosome 8, in African-ancestry analysis. Polygenic-risk prediction and concordance analysis in an independent clinically ascertained sample of developmental stuttering cases validate our GWAS findings in PheML-imputed affected and control individuals and demonstrate the clinical relevance of our population-based analysis for stuttering risk.

Consensus Guidelines for the Assessments of Individuals Who Stutter Across the Lifespan

Purpose This project sought to develop consensus guidelines for clinically meaningful, comprehensive assessment procedures for people who stutter across the lifespan. Method Twelve expert clinicians and researchers who have written extensively about stuttering provided detailed descriptions of the type of data that they routinely collect during diagnostic evaluations of preschool children, school-age children, adolescents, and adults who stutter. Iterative content analysis, with repeated input from the respondents, was used to identify core areas that reflect common domains that these experts judge to be important for evaluating stuttering for varying age groups. Results Six core areas were identified as common components of a comprehensive evaluation of stuttering and people who stutter. These areas should be included to varying degrees depending upon the age and needs of the client or family. The core areas include the following: (a) stuttering-related background information; (b) speech, language, and temperament development (especially for younger clients); (c) speech fluency and stuttering behaviors; (d) reactions to stuttering by the speaker; (e) reactions to stuttering by people in the speaker's environment; and (f) adverse impact caused by stuttering. Discussion These consensus recommendations can help speech-language pathologists who are uncertain about appropriate stuttering assessment procedures to design and conduct more thorough evaluations, so that they will be better prepared to provide individualized and comprehensive treatment for people who stutter across the lifespan.

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.

Cannabis Improves Stuttering: Case Report and Interview with the Patient

Introduction: Speech dysfluency, often referred to as stuttering, is a frequent speech disorder encountered in about 5% of children. Although in the majority of people affected, symptoms improve in adulthood, in some patients, stuttering persists and significantly impairs everyday functioning and quality of life. Treatment for stuttering includes speech therapy, cognitive behavioral therapy, and relaxation techniques. However, a substantial number of patients do not benefit sufficiently from these treatment strategies or are even treatment resistant. Methods: We present the case of a 20-year-old male with treatment-resistant stuttering, who markedly improved after treatment with medicinal cannabis. Results: Besides improved speech fluency as assessed by several phoniatric tests, we observed remission of (social) anxiety, improved mood, and reduced stress, resulting in an overall improvement of quality of life after cannabis therapy. The patient, in addition, reported improved attention, concentration, and sleep, increased self-confidence, and better social life. No side effects occurred. Over a time period of more than a year, treatment was equally effective. In an interview, the patient describes his personal view and the influence of cannabis-based treatment on his life. Conclusions: Medicinal cannabis could be effective in treatment of refractory stuttering, but these preliminary data have to be confirmed in controlled studies.