What is stuttering?

Manifestation of speech disfluencies in preschool Cantonese-English speaking bilingual children

Stuttering is characterised by disruptions in speech fluency that normally emerges between the ages of 2 to 5 when children start to formulate sentences. Current stuttering identification in children is largely based on speech disfluency criteria (>3% stuttering-like disfluencies, SLDs) developed for monolingual English-speaking children. Research in a Western language context shows that application of the criteria for monolingual to bilingual children may result in false positive diagnosis of stuttering. The applicability of these criteria to children speaking languages typologically distinct from English remains unclear. This preliminary study focused on bilingual Cantonese-English-speaking children, aiming to explore the manifestations of the speech disfluencies in Cantonese (a syllable-timed language) and English (a stress-timed language) while accounting for language dominance/proficiency and speaking task. Nineteen typically fluent Cantonese-English bilingual preschoolers were recruited for this study and their speech samples were collected across different speaking tasks (i.e. conversation and narration), and languages (i.e. Cantonese and English). The types and frequency of speech disfluencies were compared across both languages and the speaking tasks. The results showed that between 21-68% of children showed higher than 3% SLDs across different languages and speaking tasks. Linear mixed-effect analysis revealed that the prevalence of SLDs is higher in English (less dominant language) than Cantonese (more dominant language), and the prevalence is also higher in narration than conversation. These findings suggest the need for tailored stuttering identification criteria for bilingual children speaking diverse languages and emphasise the importance of considering language dominance/proficiency and speaking task when assessing stuttering in bilingual populations.

Understanding the Speaker's Experience of Stuttering Can Improve Stuttering Therapy

The purpose of this paper is to highlight the value for speech-language pathologists of considering the overall stuttering condition-including speakers' experiences during and around moments of stuttering-in treatment with individuals who stutter. We first highlight a framework for conceptualizing the entirety of the stuttering condition. We then present recent research and clinical perspectives about stuttering to support the claim that speech-language pathologists who account for individual differences in how their clients experience stuttering are better positioned to treat stuttering more effectively. Ultimately, this will yield better treatment outcomes and help clinicians achieve greater gains in quality of life for their clients who stutter.

Group Experiences and Individual Differences in Stuttering

Purpose This study explored group experiences and individual differences in the behaviors, thoughts, and feelings perceived by adults who stutter. Respondents' goals when speaking and prior participation in self-help/support groups were used to predict individual differences in reported behaviors, thoughts, and feelings. Method In this study, 502 adults who stutter completed a survey examining their behaviors, thoughts, and feelings in and around moments of stuttering. Data were analyzed to determine distributions of group and individual experiences. Results Speakers reported experiencing a wide range of both overt behaviors (e.g., repetitions) and covert behaviors (e.g., remaining silent, choosing not to speak). Having the goal of not stuttering when speaking was significantly associated with more covert behaviors and more negative cognitive and affective states, whereas a history of self-help/support group participation was significantly associated with a decreased probability of these behaviors and states. Conclusion Data from this survey suggest that participating in self-help/support groups and having a goal of communicating freely (as opposed to trying not to stutter) are associated with less negative life outcomes due to stuttering. Results further indicate that the behaviors, thoughts, and experiences most commonly reported by speakers may not be those that are most readily observed by listeners.

Stuttering as Defined by Adults Who Stutter

Purpose Numerous frameworks and definitions have sought to differentiate what behaviors and experiences should be considered as a part of stuttering. Nearly all of these efforts have been based on the perspectives and beliefs of conversational partners and listeners. This outside-in approach to defining stuttering lacks validation from people who live with the condition. Method In this study, 430 adults who stutter participated in a qualitative exploration of the term stuttering. Data were analyzed thematically to determine speakers' perspectives about moment of stuttering and the overall experience of stuttering in their lives. Results To adults who stutter, the term stuttering signifies a constellation of experiences beyond the observable speech disfluency behaviors that are typically defined as stuttering by listeners. Participants reported that the moment of stuttering often begins with a sensation of anticipation, feeling stuck, or losing control. This sensation may lead speakers to react in various ways, including affective, behavioral, and cognitive reactions that can become deeply ingrained as people deal with difficulties in saying what they want to say. These reactions can be associated with adverse impact on people's lives. This interrelated chain of events can be exacerbated by outside environmental factors, such as the reactions of listeners. Discussion Data from this survey provide novel evidence regarding what stuttering means to adults who stutter. These data are used to update the adaptation of the World Health Organization's International Classification of Functioning, Disability and Health as it applies to stuttering (Yaruss & Quesal, 2004) to better account for the complex and individualized phenotype of stuttering and to develop a definition of the experience of stuttering that is based not only on the observations of listeners but also on the impact of stuttering on the lives of adults who stutter.

Rates of Typical Disfluency in the Conversational Speech of 30-Month-Old Spanish-English Simultaneous Bilinguals

PURPOSE

The aim of this study was to investigate the typical disfluency rates at 30 months old in a large group of simultaneous bilingual children and also investigate the relationships between disfluency rates and linguistic complexity (mean length of utterance in words [MLU-W]), vocabulary diversity (VocD), and speaking rate (utterances per unit time).

METHOD

Fifty-three typically developing children who had been exposed to Spanish and English from birth participated in this descriptive study. The average percent input at home was 46% in English and 54% in Spanish. Outside the home, the children averaged 9 hr of exposure per week in each language. Spontaneous speech samples in both languages were obtained during play sessions between the children and a parent.

RESULTS

Nonparametric tests revealed a significant difference in typical disfluency rates across languages, with more children being disfluent in English and with a larger range of disfluency rates in English. The effect size for this difference was small. The children had significantly higher MLU-W in English; there were no differences in VocD or speaking rate between the 2 languages. Typical disfluency rate in Spanish was not significantly correlated with MLU-W, VocD, or speaking rate. Typical disfluency rates in English were correlated with MLU-W and VocD, but not with speaking rate.

CONCLUSION

This article described the typical disfluency rates of a large group of simultaneous Spanish-English bilingual children at 30 months of age. The typical disfluency rates reported here are lower than those reported in the literature for monolingual children of similar ages. Clinical implications of these findings are addressed.

Beyond stuttering: Speech disfluencies in normally fluent French-speaking children at age 4

The aim of this study was to establish normative data on the speech disfluencies of normally fluent French-speaking children at age 4, an age at which stuttering has begun in 95% of children who stutter (Yairi & Ambrose, 2013). Fifty monolingual French-speaking children who do not stutter participated in the study. Analyses of a conversational speech sample comprising 250-550 words revealed an average of 10% total disfluencies, 2% stuttering-like disfluencies and around 8% non-stuttered disfluencies. Possible explanations for these high speech disfluency frequencies are discussed, including explanations linked to French in particular. The results shed light on the importance of normative data specific to each language.

Scores on Riley's stuttering severity instrument versions three and four for samples of different length and for different types of speech material

Riley stated that the minimum speech sample length necessary to compute his stuttering severity estimates was 200 syllables. This was investigated. Procedures supplied for the assessment of readers and non-readers were examined to see whether they give equivalent scores. Recordings of spontaneous speech samples from 23 young children (aged between 2 years 8 months and 6 years 3 months) and 31 older children (aged between 10 years 0 months and 14 years 7 months) were made. Riley's severity estimates were scored on extracts of different lengths. The older children provided spontaneous and read samples, which were scored for severity according to reader and non-reader procedures. Analysis of variance supported the use of 200-syllable-long samples as the minimum necessary for obtaining severity scores. There was no significant difference in SSI-3 scores for the older children when the reader and non-reader procedures were used. Samples that are 200-syllables long are the minimum that is appropriate for obtaining stable Riley's severity scores. The procedural variants provide similar severity scores.

Defining stuttering for research purposes

This is a response to a Letter to the Editor entitled "Stuttering prevalence, incidence and recovery rates depend on how we define it: Comment on Yairi & Ambrose' article Epidemiology of Stuttering: 21st Century advances" by Paul Brocklehurst (2013). The criticism was directed specifically toward Yairi and Ambrose' conclusions, based on review of recent studies, regarding the incidence and prevalence of stuttering. In this response, Brocklehurst's arguments and suggestions of criteria for incidence research are discussed and negated.

Epidemiology of stuttering: 21st century advances

Epidemiological advances in stuttering during the current century are reviewed within the perspectives of past knowledge. The review is organized in six sections: (a) onset, (b) incidence, (c) prevalence, (d) developmental paths, (e) genetics and (f) subtypes. It is concluded that: (1) most of the risk for stuttering onset is over by age 5, earlier than has been previously thought, with a male-to-female ratio near onset smaller than what has been thought, (2) there are indications that the lifespan incidence in the general population may be higher than the 5% commonly cited in past work, (3) the average prevalence over the lifespan may be lower than the commonly held 1%, (4) the effects of race, ethnicity, culture, bilingualism, and socioeconomic status on the incidence/prevalence of stuttering remain uncertain, (5) longitudinal, as well as incidence and prevalence studies support high levels of natural recovery from stuttering, (6) advances in biological genetic research have brought within reach the identification of candidate genes that contribute to stuttering in the population at large, (7) subtype-differentiation has attracted growing interest, with most of the accumulated evidence supporting a distinction between persistent and recovered subtypes.

EDUCATIONAL OBJECTIVES

Readers will be exposed to a summary presentation of the most recent data concerning basic epidemiological factors in stuttering. Most of these factors also pertain to children's risks for experiencing stuttering onset, as well as risks for persistency. The article also aims to increase awareness of the implications of the information to research, and professional preparation that meets the epidemiology of the disorder.

Late childhood stuttering

PURPOSE

A study was conducted that examined factors that lead children who stutter at around age 8 years to persist in the disorder when they reach age 12 years.

METHOD

Seventy-six children were verified to be stuttering at initial assessment. When they reached 12 years of age, they were classified as persistent or recovered. A range of measures was taken at the 2 age points, and measures were examined by recovery group.

RESULTS

Although the tendency for more males than females to stutter was confirmed, the reasons for this tendency are not apparent for these speakers. Different patterns in speech were observed: Severity ratings of the recovered speakers dropped by age 12+. The severity ratings for the persistent speakers remained high at 12+, and dysfluency types tended to change from whole words to part words. Persistent and recovered speakers differed on temperamental performance at around age 8 years and performed differently on sensory and motor tasks at age 12+ years.

CONCLUSIONS

Stuttering in late childhood affects mainly males. The later a child attends clinic, the longer he or she will stutter. Speech patterns of children who persist diverge from those who recover or who are fluent. As speakers persist, there are temperamental, sensory, and motor changes.

Fluency variation in adolescents

The Speech Fluency Profile of fluent adolescent speakers of Brazilian Portuguese, were examined with respect to gender and neurolinguistic variations. Speech samples of 130 male and female adolescents, aged between 12;0 and 17;11 years were gathered. They were analysed according to type of speech disruption; speech rate; and frequency of speech disruptions. Statistical analysis did not find significant differences between genders for the variables studied. However, regarding the phases of adolescence (early: 12;0-14;11 years; late: 15;0-17;11 years), statistical differences were observed for all of the variables. As for neurolinguistic maturation, a decrease in the number of speech disruptions and an increase in speech rate occurred during the final phase of adolescence, indicating that the maturation of the motor and linguistic processes exerted an influence over the fluency profile of speech.

Signs of developmental stuttering up to age eight and at 12 plus

Clinicians who are familiar with the general DSM-IV-TR scheme may want to know how to identify whether a child does, or (equally importantly) does not, stutter and what differences there are in the presenting signs for children of different ages. This article reviews and discusses topics in the research literature that have a bearing on these questions. The review compared language, social-environmental and host factors of children who stutter across two age groups (up to age eight and 12 plus). Dysfluency types mainly involved repetition of one or more whole function words up to age eight whereas at age 12 plus, dysfluency on parts of content words often occurred. Twin studies showed that environmental and host factors were split roughly 30/70 for both ages. Though the disorder is genetically transmitted, the mode of transmission is not known at present. At the earlier age, there were few clearcut socio-environmental influences. There were, however, some suggestions of sensory (high incidence of otitis media with effusion) and motor differences (high proportion of left-handed individuals in the stuttering group relative to norms) compared to control speakers. At age 12 plus, socio-environmental influences (like state anxiety) occurred in the children who persist, but were not evident in the children who recover from the disorder. Brain scans at the older age show some replicable abnormality in the areas connecting motor and sensory areas in speakers who stutter. The topics considered in the discussion return to the question of how to identify whether a child does or does not stutter. The review identifies extra details that might be considered to improve the classification of stuttering (e.g. sensory and motor assessments). Also, some age-dependent factors and processes are identified (such as change in dysfluency type with age). Knowing the distinguishing features of the disorder allows it to be contrasted with other disorders which show superficially similar features. Two or more disorders can co-occur for two reasons: comorbidity, where the child has two identifiable disorders (e.g. a child with Down Syndrome whose speech has been properly assessed and classed as stuttering). Ambiguous classifications, where an individual suffering from one disorder meets the criteria for one or more other disorders. One way DSM-IV-TR deals with the latter is by giving certain classification axes priority over others. The grounds for such superordinacy seem circular as the main role for allowing this appears to be to avoid such ambiguities.

Subtyping stuttering II: contributions from language and temperament

This paper is the second in a series of two articles exploring subtypes of stuttering, and it addresses the question of whether and how language ability and temperament variables may be relevant to the study of subtypes within the larger population of children who stutter. Despite observations of varied profiles among young children who stutter, efforts to identify and characterize subtypes of stuttering have had limited influence on theoretical or clinical understanding of the disorder. This manuscript briefly highlights research on language and temperament in young children who stutter, and considers whether the results can provide guidance for efforts to more effectively investigate and elucidate subtypes in childhood stuttering. Issues from the literature that appear relevant to research on stuttering subtypes include: (a) the question of whether stuttering is best characterized as categorical or continuous; (b) interpretation of individual differences in skills and profiles; and (c) the fact that, during the preschool years, the interaction among domains such as language and temperament are changing very rapidly, resulting in large differences in developmental profiles within relatively brief chronological age periods.

EDUCATIONAL OBJECTIVES

The reader will be able to: (1) discuss possible associations of language ability and temperament to the development of stuttering in young children; (2) summarize the subtyping research from the literature on language ability and temperament in young children; (3) generate directions for future research of stuttering subtypes drawn from the literature related to language ability and temperament in young children.

Have disfluency-type measures contributed to the understanding and treatment of developmental stuttering?

PURPOSE

This article critically reviews evidence to determine whether the use of disfluency typologies, such as syllable repetitions or prolongations, has assisted the understanding or treatment of developmental stuttering. Consideration is given to whether there is a need for a fundamental shift in the basis for constructing measures of stuttering behavior.

METHOD

The history of using specific types of disfluencies to assess stuttering, including more recent developments such as counts of stuttering-like disfluencies, is reviewed. The focus is on studies that have investigated the validity and reliability of these perceptually based assessment methods.

CONCLUSION

The evidence from use of disfluency-type measures shows that the behavioral difference between stuttering and normally fluent speakers is solely related to the amount of observable stuttering; the differences are only partially realized within disfluency-type measures. Indeed, because disfluency-type measures show poor reliability and conflate stuttered and nonstuttered speech, they have only limited heuristic value for research and provide no obvious benefits for clinicians. At best, they should be regarded as imprecise descriptors of observable stuttering and not a fundamental measure of stuttering. A recommended solution to the problematic history of verbal-based definitions of stuttering behavior is continued development and investigation of exemplar-based definition and measurement.

The Lidcombe Behavioral Data Language of stuttering

The Lidcombe Behavioral Data Language (LBDL; K. Bryant & A. Packman, 1999; A. Packman & M. Onslow, 1998; A. Packman, M. Onslow, & K. Bryant, 2000) is a recently developed taxonomy of stuttering. It fills a void in stuttering research because most current descriptive systems are taxonomies of disfluencies, not stuttering alone, and are not behaviorally based. This study is an investigation of intrajudge and interjudge agreement for the LBDL. Ten experienced speech-language pathologists and 10 undergraduate students received brief instruction in the LBDL and then applied it to 15 intervals of stuttered speech on 2 occasions. The speakers were children and adults. Intrajudge agreement was high for both groups but only experienced judges achieved satisfactory interjudge agreement. Results suggest that some stuttering behaviors may be easier to categorize than others. Possible applications of the LBDL to research and clinical practice in stuttering are discussed.

The effect of temporal manipulation on the perception of disfluencies as normal or stuttering

The purpose of this investigation was to study the effect of temporal features within repetition of speech segments on the perception of stuttering. Past research has provided evidence that certain temporal aspects of repetitions produced by people who stutter tend to be shorter than those produced by normally fluent speakers. The effect of these temporal factors on the perception of the disfluency as "stuttering" or "normal" has not yet been studied. Conversational speech of five children who stutter was recorded. Two short utterances. one containing part-word repetition (PWR) and one containing whole-word repetition (WWR), were identified in the speech of each child and then manipulated by the CSL and CSpeech computer softwares. Two selected elements within repetitions, namely the vowel of the repeated unit and the interval between the repeated units (e.g., but-but), were lengthened to simulate normal disfluency. Results indicated that both factors (interval duration and vowel duration) moderately affected listeners' perception. In general, repetitions with short vowel and interval durations were judged as more representative of stuttering, whereas repetitions with longer vowel and interval duration were judged as more representative of normal speech.

LEARNING OUTCOMES

As a result of this activity, the reader will learn about (1) various factors that influence the perception of disfluent segments as stuttering, (2) the special effect of duration of specific elements within repetitions on the perception of disfluency as stuttering, and (3) the possible implications of the new information for therapeutic considerations.