The nature and treatment of stuttering as revealed by fMRI A within- and between-group comparison

This article reviews some of our recent functional magnetic resonance imaging (fMRI) studies of stuttering. Using event-related fMRI experiments, we investigated brain activation during speech production. Results of three studies comparing persons who stutter (PWS) and persons who do not stutter (PWNS) are outlined. Their findings point to a region in the right frontal operculum (RFO) that was consistently implicated in stuttering. During overt reading and before fluency shaping therapy, PWS showed higher and more distributed neuronal activation than PWNS. Immediately after therapy differential activations were even more distributed and left sided. They extended to frontal, temporal, and parietal regions, anterior cingulate, insula, and putamen. These over-activations were slightly reduced and again more right sided two years after therapy. Left frontal deactivations remained stable over two years of observation, and therefore possibly indicate a dysfunction. After therapy, we noted higher activations in persons who stutter moderately than in those who stutter severely. These activations might reflect patterns of compensation. We discuss why these findings suggest that fluency-inducing techniques might synchronize a disturbed signal transmission between auditory, speech motor planning, and motor areas.

Educational objectives: The reader will learn about and be able to: (1) identify regions of brain activations and deactivations specific for PWS; (2) describe brain activation changes induced by fluency shaping therapy; and (3) discuss the correlation between stuttering severity and brain activation.     

Gestural overlap in consonant clusters: effects on the fluent speech of stuttering and non-stuttering subjects

This study was designed to investigate if persons who stutter differ from persons who do not stutter in the coproduction of different types of consonant clusters, as measured in the number of dysfluencies and incorrect speech productions, in speech reaction times and in word durations. Based on the Gestural Phonology Model of Browman and Goldstein, two types of consonant clusters were formed: homorganic and heterorganic clusters, both intra-syllabic (CVCC) and inter-syllabic (CVC#CVC). Overall, the results indicated that homorganic clusters elicited more incorrect speech productions and longer reaction times than the heterorganic clusters, but there was no difference between the homorganic and the heterorganic clusters in the word duration data. Persons who stutter showed a higher percentage dysfluencies and a higher percentage incorrect speech productions than PWNS but there were no main group effects in reaction times and word durations. However, there was a significant three-way interaction effect between group, cluster type and cluster place: homorganic clusters elicited longer reaction times than heterorganic clusters, but only in the inter-syllabic condition and only for persons who stutter. These results suggest that the production of two consonants with the same place of articulation across a syllable boundary puts higher demands on motor planning and/or initiation than producing the same cluster at the end of a syllable, in particular for PWS. The findings are discussed in light of current theories on speech motor control in stuttering. EDUCATIONAL OBJECTIVES: The reader will be able to describe: (1) the effect of gestural overlap between consonant clusters on speech reaction time and word duration of people who do and do not stutter and be able to (2) identify the literature in the field of gestural overlap between consonant clusters.     

Responses of adults who stutter to the anticipation of stuttering

PurposeMany people who stutter experience the phenomenon of anticipation—the sense that stuttering will occur before it is physically and overtly realized. A systematic investigation of how people who stutter respond to anticipation has not been previously reported. The purposes of this study were to provide self-report evidence of what people do in response to anticipation of stuttering and to determine the extent to which this anticipation occurs.MethodsThirty adults who stutter indicated on a Likert rating scale the extent to which they anticipate stuttering and answered three open-ended (written) questions regarding how they respond to anticipation.ResultsAll participants reported experiencing anticipation at least “sometimes,” and 77% of the participants reported experiencing anticipation “often” or “always.” The extent to which participants reported experiencing anticipation was not related to stuttering severity, impact, or treatment history. Analysis of written responses revealed 24 major categories, which were heuristically divided into action or non-action responses. Categories representing avoidance and self-management strategies were further divided into 14 and 19 subcategories, respectively. Participants were just as likely to view anticipation as helpful as they were to view it as harmful.ConclusionFindings demonstrate that most, if not all, adults who stutter experience anticipation, and the majority of adults who stutter report doing so at least often. Adults who stutter respond to this anticipation by altering the speech production process in various ways. Results highlight the importance of the role that anticipation plays in how stuttering behaviors manifest themselves.Educational Objectives: The reader will be able to: (a) summarize existing literature on the anticipation of stuttering; (b) describe the role and extent of anticipation of stuttering in adults; (c) describe the various ways that adults who stutter respond to anticipation; (d) describe the importance of measuring anticipation in clinical and research domains.     

口吃者的言语计划缺陷——来自词长效应的证据

口吃者与非口吃者在词长效应上的差异是口吃语音编码缺陷的一个重要的支持证据。本研究在综述词长效应研究的基础上,对这种解释提出了三点置疑,即词频、句法复杂性和发音长度也可能是造成词长效应差异的主要原因,并通过三个实验进行了验证。实验一和实验三在口吃者和非口吃者之间都得到了稳定的词长效应差异,并且排除了词频和发音长度对于这种差异的影响;实验二在控制词长的条件下,发现口吃者对于句法复杂性是敏感的。因此,本研究的结果支持口吃在言语产出中的语音编码和句法编码中都存在缺陷。同时,本研究对于口吃治疗也提供了有价值的参考建议     

The influence of workplace discrimination and vigilance on job satisfaction with people who stutter

Purpose The purpose of the present study is to examine the association between workplace discrimination, vigilance, and job satisfaction in people who stutter and compare this with people who do not stutter. Method Seventy-two people who stutter (PWS) and 92 people who do not stutter (PWNS) participated in an online survey. Participants completed a survey assessing 6 different areas: (a) background information, (b) job satisfaction, (c) everyday discrimination, and (d) heightened vigilance. Mediation analyses were conducted to evaluate the relationship between the independent variables and dependent variable. Results There was a relationship between being a PWS and job satisfaction, discrimination, and vigilance. PWS were found to experience higher discrimination as well as be more vigilant. Discrimination and vigilance were found to mediate the relationship between stuttering and job satisfaction. Conclusion Results of this study indicate that the participants who stutter differ from PWNS in their job satisfaction, discrimination, and vigilance. Clinicians can prepare PWS with self-advocacy strategies, legal knowledge of what their rights are as an employee who identifies as a person who stutters with a disability, a legal understanding of workplace discrimination, and counseling on the impact of vigilance on workplace experiences.     

Speeded verbal responding in adults who stutter: are there deficits in linguistic encoding?

Linguistic encoding deficits in people who stutter (PWS, n=18) were investigated using auditory priming during picture naming and word vs. non-word comparisons during choice and simple verbal reaction time (RT) tasks. During picture naming, PWS did not differ significantly from normally fluent speakers (n=18) in the magnitude of inhibition of RT from semantically related primes and the magnitude of facilitation from phonologically related primes. PWS also did not differ from controls in the degree to which words were faster than non-words during choice RT, although PWS were slower overall than controls. Simple RT showed no difference between groups, or between words and non-words, suggesting differences in speech initiation time do not explain the choice RT results. The findings are consistent with PWS not being deficient in the time course of lexical activation and selection, phonological encoding, and phonetic encoding. Potential deficits underlying slow choice RTs outside of linguistic encoding are discussed. EDUCATIONAL OBJECTIVES: The reader will be able to (1) describe possible relationships between linguistic encoding processes and speech motor control difficulties in people who stutter; (2) explain the role of lexical priming tasks during speech production in evaluating the efficiency of linguistic encoding; (3) describe the different levels of processing that may be involved in slow verbal responding by people who stutter, and identify which levels could be involved based on the findings of the present study.     

The speech naturalness of people who stutter speaking under delayed auditory feedback as perceived by different groups of listeners

This study investigated listeners' perception of the speech naturalness of people who stutter (PWS) speaking under delayed auditory feedback (DAF) with particular attention for possible listener differences. Three panels of judges consisting of 14 stuttering individuals, 14 speech language pathologists, and 14 naive listeners rated the naturalness of speech samples of stuttering and non-stuttering individuals using a 9-point interval scale. Results clearly indicate that these three groups evaluate naturalness differently. Naive listeners appear to be more severe in their judgements than speech language pathologists and stuttering listeners, and speech language pathologists are apparently more severe than PWS. The three listener groups showed similar trends with respect to the relationship between speech naturalness and speech rate. Results of all three indicated that for PWS, the slower a speaker's rate was, the less natural speech was judged to sound. The three listener groups also showed similar trends with regard to naturalness of the stuttering versus the non-stuttering individuals. All three panels considered the speech of the non-stuttering participants more natural. EDUCATIONAL OBJECTIVES: The reader will be able to: (1) discuss the speech naturalness of people who stutter speaking under delayed auditory feedback, (2) discuss listener differences about the naturalness of people who stutter speaking under delayed auditory feedback, and (3) discuss the importance of speech rate for the naturalness of speech.     

Self-acceptance,resilience, coping and satisfaction of life in people who stutter

PurposeThe purpose of the present study was to evaluate self-acceptance and satisfaction with life with people who stutter and the influence of coping and resilience on the two factors.MethodForty-seven people who stutter (PWS) and 47 people who do not stutter (PWNS) participated in an online survey. Participants completed a survey assessing 6 main areas: (a) background information, (b) satisfaction with life, (c) coping, (d) avoidance, (e) self-acceptance, and resilience.ResultsAvoidant coping and maladaptive coping moderated the association between stuttering and self- acceptance but not satisfaction with life. Resilience was found to moderate the association between stuttering and self-acceptance as well as satisfaction with life.ConclusionStuttering was associated with lower self-acceptance at higher levels of avoidant coping and maladaptive coping. PWS who have lower levels of resilience were more likely to have a lower satisfaction with life indicating that higher levels of resilience could serve as a protective factor for having a greater satisfaction with life. Further, stuttering was associated with lower self-acceptance at lower levels of resilient attitude. Resilience and coping appear to protect against having diminished self-acceptance and satisfaction with life for PWS.     

The impact of threat and cognitive stress on speech motor control in people who stutter

PurposeIn the present study, an Emotional Stroop and Classical Stroop task were used to separate the effect of threat content and cognitive stress from the phonetic features of words on motor preparation and execution processes.MethodA group of 10 people who stutter (PWS) and 10 matched people who do not stutter (PNS) repeated colour names for threat content words and neutral words, as well as for traditional Stroop stimuli. Data collection included speech acoustics and movement data from upper lip and lower lip using 3D EMA.ResultsPWS in both tasks were slower to respond and showed smaller upper lip movement ranges than PNS. For the Emotional Stroop task only, PWS were found to show larger inter-lip phase differences compared to PNS. General threat words were executed with faster lower lip movements (larger range and shorter duration) in both groups, but only PWS showed a change in upper lip movements. For stutter specific threat words, both groups showed a more variable lip coordination pattern, but only PWS showed a delay in reaction time compared to neutral words. Individual stuttered words showed no effects. Both groups showed a classical Stroop interference effect in reaction time but no changes in motor variables.ConclusionThis study shows differential motor responses in PWS compared to controls for specific threat words. Cognitive stress was not found to affect stuttering individuals differently than controls or that its impact spreads to motor execution processes.Educational objectives: After reading this article, the reader will be able to: (1) discuss the importance of understanding how threat content influences speech motor control in people who stutter and non-stuttering speakers; (2) discuss the need to use tasks like the Emotional Stroop and Regular Stroop to separate phonetic (word-bound) based impact on fluency from other factors in people who stutter; and (3) describe the role of anxiety and cognitive stress on speech motor processes.     

Recurrent involuntary imagery in people who stutter and people who do not stutter

Objective

To compare intrusive memories in groups of people who do (PWS), and who do not (PWNS), stutter.

Method

Twenty-one participants who stuttered and 21 matched controls were given a semi-structured interview which explored imagery in speaking situations. The data were analyzed using a Content Analysis approach. Other outcome measures were the Beck Anxiety Inventory, the Beck Depression Inventory, the Post Traumatic Stress Disorder, PTSD, Symptom Scale: Self-Report Version.

Results

Significantly more stuttering participants than control participants indicated both recurrent imagery and associated memories. Content Analysis revealed themes of disfluency, anxiety, negative social evaluation, self-focus and pressure to speak that were common to both groups’ reports. Additional themes of helplessness, shame, sadness and frustration were found only in the images and memories of the stuttering group. No group differences were evident for the number of sensory modalities involved in images and memories, or for ratings of their vividness or strength of associated emotions, or on self-reports of depression, anxiety and trauma.

Conclusions

Recurrent imagery about events in childhood is a potent factor in the memories of PWS. It is worth modifying interventions that have been successfully applied for treating social anxiety for use with people who stutter.Educational objectives: After reading this article, participants will be able to: (a) identify the role of intrusive memories in psychiatric disorders and stuttering; (b) investigate how DSM criteria can be employed with people who stutter; (c) employ anxiety instruments used for assessing psychiatric disorders for stuttering; (d) distinguish between the intrusive memories experienced by people who stutter, and people who do not stutter; (e) apply treatments for intrusive memories in psychiatric disorders to work with people who stutter.     

A comparative investigation of the speech-associated attitude of preschool and kindergarten children who do and do not stutter

The data of recent research studies have shown that by 3 years of age children show an awareness of dysfluency and that by at least the age of six, youngsters who stutter have a speech-associated attitude that is more negative than that of their peers. These findings led to the present study in which the KiddyCAT, a self-report measure, was used to compare the attitude toward speech of 45 children, between the age of three and six, who stuttered with that of 63 who did not. The data of this investigation showed that, as a group, the preschool and kindergarten children who stuttered had significantly more in the way of a negative attitude toward their speech than was found among their nonstuttering peers of the same age and gender. This finding is not consistent with the classically held position that the reactive aspects of stuttering do not generally develop until well after its onset. It suggests the need to measure, by standardized means, the speech-associated attitude of incipient stutterers and, when appropriate, to make the assessment and treatment of negative attitude toward speech a meaningful aspect of therapy.

Educational objectives: The reader will be able to: (1) describe the difference in the speech-associated attitude of preschoolers and kindergartners who do and do not stutter; (2) summarize what we currently know about self-report tests used to assess speech-related attitude among children as young as 3; and (3) evaluate the usefulness of assessing the belief system of children whose fluency is considered problematic.     

Investigating speech motor practice and learning in people who stutter

In this exploratory study, we investigated whether or not people who stutter (PWS) show motor practice and learning changes similar to those of people who do not stutter (PNS). To this end, five PWS and five PNS repeated a set of non-words at two different rates (normal and fast) across three test sessions (T1, T2 on the same day and T3 on a separate day, at least 1 week apart). The results indicated that PWS and PNS may resemble each other on a number of performance variables (such as movement amplitude and duration), but they differ in terms of practice and learning on variables that relate to movement stability and strength of coordination patterns. These findings are interpreted in support of recent claims about speech motor skill limitations in PWS.

Educational objectives: The reader will be able to: (1) define oral articulatory changes associated with motor practice and learning and their measurement; (2) summarize findings from previous studies examining motor practice and learning in PWS; and (3) discuss hypotheses that could account for the present findings that suggest PWS and PNS differ in their speech motor learning abilities.     

准备间隔对口吃者言语反应速度的影响

为了考察准备间隔对口吃者言语反应速度的影响,作者采用固定准备间隔下的预备反应时范式,设置了6种准备间隔,通过三个系列实验,检测口吃者的最佳言语准备间隔。结果发现,无论时间压力（项目间隔）怎样变化,口吃被试的问题在于,当准备间隔增加到800ms时,他们无法有效保持或提高反应速度;而且,这一现象只在言语命名任务上表现明显。作者认为,口吃者在言语运动准备过程中的异常,很可能是引起口吃现象的重要原因。     

Stuttering, emotions, and heart rate during anticipatory anxiety: a critical review

Persons who stutter often report their stuttering is influenced by emotional reactions, yet the nature of such relation is still unclear. Psychophysiological studies of stuttering have failed to find any major association between stuttering and the activity of the sympathetic nervous system. A review of published studies of heart rate in relation to stressful speech situations indicate that adults who stutter tend to show a paradoxical reduction of heart rate compared with nonstuttering persons. Reduction of heart rate has also been observed in humans and mammals during anticipation of an unpleasant stimulus, and is proposed to be an indication of anticipatory anxiety resulting in a "freezing response" with parasympathetic inhibition of the heart rate. It is suggested that speech-related anticipatory anxiety in persons who stutter is likely to be a secondary, conditioned reaction based on previous experiences of stuttering. EDUCATIONAL OBJECTIVES: The reader will be able to: (1) describe how the autonomic nervous system is modulated by emotional responses; (2) explain how anticipatory fear often results in inhibition of heart rate due to parasympathetic activation; (3) discuss why emotional reactions in persons who stutter may be secondary to negative experiences of speech problems.     

Life partners’ perceptions of the emotional,speech disruptive,and attitudinal correlates of stuttering

PurposeThe purpose of the current investigation was to explore the extent to which the life partners (LPs) of people who stutter (PWS) perceive their loved ones’ speech-situation specific emotional reaction, expectancy of speech disruption, and speech-related communication attitude.MethodsThree subtests of the Behavior Assessment Battery (BAB): the Speech Situation Checklist - Emotional Reaction (SSC-ER), the Speech Situation Checklist - Speech Disruption (SSC-SD) and the Communication Attitude Test for Adults Who Stutter (BigCAT) were administered to 33 PWS and modified versions were administered to their LPs via Qualtrics Survey Software. Effect of relationship duration on subtest scores was considered. Perceived stuttering severity by the participant and their LP was also queried as part of a demographic questionnaire.ResultsPWS and their LPs rated BigCAT items in a similar way, while they rated certain SSC-ER and SSC-SD items differently. Importantly, between-group agreement was not affected by relationship duration. Among the PWS and LP, perceived stuttering severity influenced all BAB subtest scores.ConclusionLPs of PWS appear to be in tune with the cognitive aspects of their partner’s experience of stuttering. This has important clinical implications as it relates to active involvement of the family in speech intervention targeting fluency.     

Coping with a child who stutters: A phenomenological analysis

Qualitative methods were used in the form of a phenomenological analysis to explore how families cope with having a child who stutters. Twelve participants, 2 men and 10 women, who have children who stutter participated in this study. The participants were asked to consider their experiences with being the parent of a child who stutters. Analysis of these data resulted in 3 primary categories. The results indicate that parents experience and cope with stresses associated with being the parent of a child who stutters. The participants described feelings of uncertainty and concern as well as the desire to do what is best for their children. Results highlight the importance of providing information and avenues of support that will help parents more effectively cope with having a child who stutters.Educational objectives: The reader will be able to: (a) describe, from the perspective of a parent of a child who stutters, the themes associated with the process of coping with a child who stutters, (b) describe types of coping resources, (c) describe the factors that influence the choice to use emotion-focused and problem-focused coping strategies, and (d) describe four specific areas to consider when providing resources for families of children who stutter.     

Systematic studies of modified vocalization: speech production changes during a variation of metronomic speech in persons who do and do not stutter

The most common way to induce fluency using rhythm requires persons who stutter to speak one syllable or one word to each beat of a metronome, but stuttering can also be eliminated when the stimulus is of a particular duration (e.g., 1 second [s]). The present study examined stuttering frequency, speech production changes, and speech naturalness during rhythmic speech that alternated 1 s of reading with 1 s of silence. A repeated-measures design was used to compare data obtained during a control reading condition and during rhythmic reading in 10 persons who stutter (PWS) and 10 normally fluent controls. Ratings for speech naturalness were also gathered from naïve listeners. Results showed that mean vowel duration increased significantly, and the percentage of short phonated intervals decreased significantly, for both groups from the control to the experimental condition. Mean phonated interval length increased significantly for the fluent controls. Mean speech naturalness ratings during the experimental condition were approximately “7” on a 1–9 scale (1 = highly natural; 9 = highly unnatural), and these ratings were significantly correlated with vowel duration and phonated intervals for PWS. The findings indicate that PWS may be altering vocal fold vibration duration to obtain fluency during this rhythmic speech style, and that vocal fold vibration duration may have an impact on speech naturalness during rhythmic speech. Future investigations should examine speech production changes and speech naturalness during variations of this rhythmic condition.Educational objectives: The reader will be able to: (1) describe changes (from a control reading condition) in speech production variables when alternating between 1 s of reading and 1 s of silence, (2) describe which rhythmic conditions have been found to sound and feel the most natural, (3) describe methodological issues for studies about alterations in speech production variables during fluency-inducing conditions, and (4) describe which fluency-inducing conditions have been shown to involve a reduction in short phonated intervals.     

Anxiety and speaking in people who stutter: An investigation using the emotional Stroop task

People with anxiety disorders show an attentional bias towards threat or negative emotion words. This exploratory study examined whether people who stutter (PWS), who can be anxious when speaking, show similar bias and whether reactions to threat words also influence speech motor planning and execution. Comparisons were made between 31 PWS and 31 fluent controls in a modified emotional Stroop task where, depending on a visual cue, participants named the colour of threat and neutral words at either a normal or fast articulation rate. In a manual version of the same task participants pressed the corresponding colour button with either a long or short duration. PWS but not controls were slower to respond to threat words than neutral words, however, this emotionality effect was only evident for verbal responding. Emotionality did not interact with speech rate, but the size of the emotionality effect among PWS did correlate with frequency of stuttering. Results suggest PWS show an attentional bias to threat words similar to that found in people with anxiety disorder. In addition, this bias appears to be contingent on engaging the speech production system as a response modality. No evidence was found to indicate that emotional reactivity during the Stroop task constrains or destabilises, perhaps via arousal mechanisms, speech motor adjustment or execution for PWS.Educational objectives: The reader will be able to: (1) explain the importance of cognitive aspects of anxiety, such as attentional biases, in the possible cause and/or maintenance of anxiety in people who stutter, (2) explain how the emotional Stroop task can be used as a measure of attentional bias to threat information, and (3) evaluate the findings with respect to the relationship between attentional bias to threat information and speech production in people who stutter.     

Effects of stuttering severity and therapy involvement on attitudes towards people who stutter

The purpose of this study was to explore whether stuttering severity or therapy involvement had an effect on the attitudes that individuals who do not stutter reported towards people who stutter (PWS). Two hundred and sixty (260) university students participated in this study. Direct survey procedures consisting of a 25-item semantic differential scale were utilized. Comparisons of the effects of stuttering severity, level of therapy involvement, and the interaction of these variables were completed. Results suggested that both stuttering severity and therapy involvement had significant effects on participants' attitudes towards PWS. Findings of this study support past research studies that has found that individuals who stutter mildly are perceived more positively than those who are severe. Similarly, the data supported past research that has found that PWS that attend therapy are perceived more positively than those who do not attend therapy. Surprisingly, the interaction of these variables was not significant. EDUCATIONAL OBJECTIVES: The reader will be able to: (1) explain the possible effects of listeners' attitudes toward stuttering on the lives of PWS; (2) discuss how different factors might alter listeners' attitudes towards stuttering; (3) delineate how stuttering severity and involvement in therapy might impact listeners' attitudes towards PWS.