Stuttering associated with a pathogenic variant in the chaperone protein cyclophilin 40.

Stuttering is a common speech disorder that interrupts speech fluency and tends to cluster in families. Typically, stuttering is characterized by speech sounds, words or syllables which may be repeated or prolonged and speech that may be further interrupted by hesitations or 'blocks'. Rare variants in a small number of genes encoding lysosomal pathway proteins have been linked to stuttering. We studied a large four-generation family in which persistent stuttering was inherited in an autosomal dominant manner with disruption of the cortico-basal-ganglia-thalamo-cortical network found on imaging. Exome sequencing of three affected family members revealed the PPID c.808C>T (p.Pro270Ser) variant that segregated with stuttering in the family. We generated a Ppid p.Pro270Ser knock-in mouse model and performed ex vivo imaging to assess for brain changes. Diffusion-weighted MRI in the mouse revealed significant microstructural changes in the left corticospinal tract, as previously implicated in stuttering. Quantitative susceptibility mapping also detected changes in cortico-striatal-thalamo-cortical loop tissue composition, consistent with findings in affected family members. This is the first report to implicate a chaperone protein in the pathogenesis of stuttering. The humanized Ppid murine model recapitulates network findings observed in affected family members.

Trait perspective-taking and need for cognition in the formation of stereotypes about people who stutter.

People who stutter (PWS) suffer from stereotypes portraying them as timid and anxious, which may affect their relationships and careers. One of the mechanisms for this stereotyping is the anchoring and adjustment heuristic, whereby individuals make judgements about PWS by using previous experiences for the initial judgement and then adjust accordingly. In the current study (n = 309) we replicate previous findings that individuals stereotype PWS by anchoring to experiences with episodic stuttering and adjusting toward typical non-stuttering individuals, although insufficiently. We extend this finding by testing whether trait perspective-taking and need for cognition moderate this relationship. The results show that trait perspective-taking decreases stereotyping of non-PWS, while having no effect on PWS stereotyping. However, need for cognition exhibited no consistent moderating effect on stereotyping.

Comparison of social anxiety between Japanese adults who stutter and non-stuttering controls.

PURPOSE: Adults who stutter (AWS) often develop social anxiety disorder. This study was to provide comparative data on the Liebowitz Social Anxiety Scale-Japanese version (LSAS-J) from AWS and non-stuttering adult controls. METHODS: LSAS-J, a 24-item self-reported survey of social phobia and avoidance across various daily situations, was administered to 130 AWS (Mean Age = 41.5 years, SD = 15.8, 111 males) and 114 non-stuttering adults (Mean Age = 39.5, SD = 14.9, 53 males). The test-retest reliability and internal consistency of the LSAS-J were assessed. A between-subject multivariate analysis of variance (MANOVA) was also conducted to determine whether attitude toward social anxiety differed between AWS and AWNS, or by age (<40 and ≥ 40 years old), or sex (female and male). RESULTS: AWS reported higher scores on both fear subscales of the LSAS-J. Age had no significant influence on the social anxiety levels reported by either participant group. Sex differences were found in the fear subscales, with females scoring higher on both fear subscales, although these were only marginally significant (p = .06). LSAS-J showed good test-retest reliability and high Cronbach's alpha coefficient, indicating that it is an internally consistent measure of attitudes about social anxiety. CONCLUSION: Given the similarly high incidence of social anxiety in adults in Japan who stutter compared with those in other countries, social anxiety should be identified and assessed during clinical decision making and before decisions are made about stuttering treatment. LSAS-J is an easy tool to administer, and showed reliable results of social phobia and avoidance for AWS.

A parent-report scale of behavioral inhibition: Validation and application to preschool-age children who do and do not stutter.

PURPOSE: This two-part (i.e., Study 1, Study 2) study investigated behavioral inhibition (BI) in preschool-age children who do (CWS) and do not (CWNS) stutter. The purpose of Study 1 was to develop the Short Behavioral Inhibition Scale (SBIS), a parent-report scale of BI. The purpose of Study 2 was to determine, based on the SBIS, differences in BI between CWS and CWNS, and associations between BI and CWS's stuttering frequency, stuttering severity, speech-associated attitudes, and stuttering-related consequences/reactions. METHOD: Participants in Study 1 were 225 CWS and 243 CWNS with the majority of them being included in Study 2. In Study 2, a speech sample was obtained for the calculation of stuttering frequency and severity, and the parents of a subset of CWS completed the Communication Attitude Test for Preschool and Kindergarten Children Who Stutter (Vanryckeghem & Brutten, 2007), and the Test of Childhood Stuttering Disfluency-Related Consequences Rating Scale (Gillam, Logan, & Pearson, 2009). RESULTS: Study 1 analyses indicated that SBIS is a valid and reliable tool whose items assess a single, relatively homogeneous construct. In Study 2, CWS exhibited greater mean and extreme BI tendencies than CWNS. Also CWS with higher, compared to CWS with lower, BI presented with greater stuttering frequency, more severe stuttering, greater stuttering-related consequences, and more negative communication attitudes (for CWS older than 4 years of age). CONCLUSION: Findings were taken to suggest that BI is associated with early childhood stuttering and that the SBIS could be included as part of a comprehensive evaluation of stuttering.

Neuroanatomical Correlates of Childhood Stuttering: MRI Indices of White and Gray Matter Development That Differentiate Persistence Versus Recovery.

Purpose We review two recent neuroanatomical studies of children who stutter (CWS), one that examines white matter integrity and the other that focuses on cortical gray matter morphology. In both studies, we sought to examine differences between children whose stuttering persists ("persistent"), children who recovered from stuttering ("recovered"), and their nonstuttering peers ("controls"). Method Both of the reviewed studies use data from a large pediatric sample spanning preschool- to school-age children (3-10 years old at initial testing). Study 1 focused on surface-based measures of cortical size (thickness) and shape (gyrification) using structural magnetic resonance imaging, whereas Study 2 utilized diffusion tensor imaging to examine white matter integrity. Results In both studies, the main difference that emerged between CWS and fluent peers encompassed left hemisphere speech motor areas that are interconnected via the arcuate fasciculus. In the case of white matter integrity, the temporoparietal junction and posterior superior temporal gyrus, both connected via the left arcuate fasciculus, and regions along the corpus callosum that contain fibers connecting bilateral motor regions were significantly decreased in white matter integrity in CWS compared to controls. In the morphometric study, children who would go on to have persistent stuttering specifically had lower cortical thickness in ventral motor and premotor areas of the left hemisphere. Conclusion These results point to aberrant development of cortical areas involved in integrating sensory feedback with speech movements in CWS and differences in interhemispheric connectivity between the two motor cortices. Furthermore, developmental trajectories in these areas seem to diverge between persistent and recovered cases.

Ventral striatum and stuttering: Robust evidence from a case-control study applying DARTEL.

A prominent theory of developmental stuttering highlights (dys-)function of the basal ganglia (and in particular the ventral striatum) as a main neural mechanism behind this speech disorder. Although the theory is intriguing, studies on gray matter volume differences in the basal ganglia between people who stutter and control persons have reported heterogeneous findings, either showing more or less gray matter volume of the aforementioned brain structure across the brain's hemispheres. Moreover, some studies did not observe any differences at all. From today's perspective several of the earlier studies are rather underpowered and also used less powerful statistical approaches to investigate differences in brain structure between people who stutter and controls. Therefore, the present study contrasted a comparably larger sample of n = 36 people who stutter with n = 34 control persons and applied the state of the art DARTEL algorithm (Diffeomorphic Anatomical Registration Through Exponentiated Lie algebra) to analyze the available brain data. In the present data set stuttering was associated with higher gray matter volume of the right caudate and putamen region of the basal ganglia in patients. Our observation strongly supports a recent finding reporting a larger nucleus accumbens in the right hemisphere in people who stutter when compared to control persons. The present findings are discussed in the context of both compensatory effects of the brain and putative therapeutic effects due to treatment of stuttering.

Adults who stutter and metronome synchronization: evidence for a nonspeech timing deficit.

Speech timing deficits have been proposed as a causal factor in the disorder of stuttering. The question of whether individuals who stutter have deficits in nonspeech timing is one that has been revisited often, with conflicting results. Here, we uncover subtle differences in a manual metronome synchronization task that included tempo changes with adults who stutter and fluent speakers. We used sensitive circular statistics to examine both asynchrony and consistency in motor production. While both groups displayed a classic negative mean asynchrony (tapping before the beat), individuals who stutter anticipated the beat even more than their fluent peers, and their consistency was particularly affected at slow tempi. Surprisingly, individuals who stutter did not have problems with interval correction at tempo changes. We also examined the influence of music experience on synchronization behavior in both groups. While music perception and training were related to synchronization behavior in fluent participants, these correlations were not present for the stuttering group; however, one measure of stuttering severity (self-rated severity) was negatively correlated with music training. Overall, we found subtle differences in paced auditory-motor synchronization in individuals who stutter, consistent with a timing problem extending to nonspeech.

Functional and Neuroanatomical Bases of Developmental Stuttering: Current Insights.

Affecting 5% of all preschool-aged children and 1% of the general population, developmental stuttering-also called childhood-onset fluency disorder-is a complex, multifactorial neurodevelopmental disorder characterized by frequent disruption of the fluent flow of speech. Over the past two decades, neuroimaging studies of both children and adults who stutter have begun to provide significant insights into the neurobiological bases of stuttering. This review highlights convergent findings from this body of literature with a focus on functional and structural neuroimaging results that are supported by theoretically driven neurocomputational models of speech production. Updated views on possible mechanisms of stuttering onset and persistence, and perspectives on promising areas for future research into the mechanisms of stuttering, are discussed.

Self-report of self-disclosure statements for stuttering.

PURPOSE: To (1) analyze verbatim wording used by adults who stutter (AWS) to self-disclose stuttering, (2) determine contexts in which AWS may self-disclose, (3) examine the use of self-disclosure by AWS about other aspects of their identity, and (4) investigate the ways in which speech-language pathologists (SLPs) develop self-disclosure statements with AWS. METHOD: Web-based questionnaires were administered to AWS (N = 42) and SLPs (N = 33) who work with AWS. The AWS questionnaire asked about the verbatim wording of self-disclosure statements used by AWS and the contexts in which they utilize them. For SLPs, the questionnaire probed how and why they work with AWS to formulate self-disclosure statements. Responses were openly coded and then funneled into concepts for analysis. RESULTS: The majority of AWS provided verbatim self-disclosure statements which were educational in nature. However, when responding to fixed choices and when reporting on self-disclosing other aspects of their lives, the majority of participants selected a direct statement. The majority of AWS reported that they self-disclose when interviewing for a job. SLPs reportedly instruct their clients to use educational self-disclosure statements. SLPs also reported that they use an individualized approach to brainstorming self-disclosure statements. Finally, SLPs reported that they find self-disclosure beneficial because it facilitates self-empowerment for AWS. CONCLUSION: AWS may benefit from learning about the type of self-disclosure statements and the contexts in which other AWS chose to disclose. Additionally, SLPs who work with AWS may benefit from the reported procedures for and types of self-disclosure statements formulated by AWS.

Envelope modulation spectral (EMS) analyses of solo reading and choral reading conditions suggest changes in speech rhythm in adults who stutter.

PURPOSE: A longstanding finding in persons who stutter is that stuttering frequency significantly reduces during choral reading when compared to the solo reading condition. Here, we tested the hypothesis that this decrease in stuttering frequency may be because speech of the normal speaker dictates the speech rhythm of a person who stutters. We used an automated, sensitive acoustic technique-Envelope Modulation Spectral (EMS) analysis- that allowed us to document speech rhythm. METHOD: Seventeen adults who stutter (AWS) read sentences under two conditions: solo reading and choral reading. Percentage of syllables stuttered (%SS), the rate of speech, and speech rhythm were calculated from the recorded sentences from AWS. Further, AWS speech rhythm during solo reading was compared with typical adults. EMS was extracted for the full signal and seven-octave bands. From the extracted envelope six predictor variables (peak frequency, peak amplitude, energy in the spectrum 3-6 Hz, energy in the spectrum from 0 to 4 Hz, energy in the spectrum from 4 to 10 Hz, and the ratio of energy below4 Hz/above 4 Hz) were computed. RESULTS: Significant decrease in stuttering frequency and rate of speech was noticed in choral reading when compared to the solo reading condition. Further, analysis of EMS results suggested the statistically significant difference between two reading conditions (for peak frequency and peak amplitude), and between two groups for all predictor variables. CONCLUSION: Overall, current results highlight that decreases in stuttering during the choral reading is characterized by a decrease in rate and changes in some aspects of speech rhythm in Kannada speaking AWS.

The Speech Efficiency Score (SES): A time-domain measure of speech fluency.

PURPOSE: This study is a preliminary attempt to evaluate a new speech fluency measure, the Speech Efficiency Score (SES), in comparison with subjective stuttering severity rating scales and stuttered syllable counts (%SS). METHODS: 277 listeners (92 naïve, 39 speech-language pathology (SLP) students, 124 practicing SLPs, and 22 SLPs who specialize in stuttering) evaluated short recordings of speech on an 11-point scale. Recordings were obtained from 56 adults, of whom 20 were people who stutter, 16 were people who stutter who were using fluency-shaping techniques, and 20 were speakers who do not stutter. In addition, %SS and the SES measure were obtained for each recording. RESULTS: The four listener groups rated stuttering severity similarly, with no statistically significant between-group differences. Listeners' responses on the stuttering severity rating scales and the SES yielded significant differences between all three speaker groups. The %SS measure yielded a significant difference only between the stuttering group and the other two groups but not between the fluency-shaping and the control groups. A very strong positive correlation was found between the SES and the subjective stuttering-severity rating scales (r = 0.92). The correlation between %SS and the perceptual evaluation, as well as the correlation between %SS and the SES, were lower, though they still reached significance. CONCLUSIONS: Results suggest that speech efficiency scores, which are based on a time-domain analysis, closely match subjective stuttering severity ratings and could ultimately provide a more objective way to measure speech fluency.

Backward masking of tones and speech in people who do and do not stutter.

PURPOSE: There is evidence of an auditory-perceptual component of stuttering, and backward masking (BM) is a task to explore that role. Prior research reported poorer thresholds for BM tones in a group of children who persisted in stuttering compared to those for a group that did not persist. This study examined BM for adults who stutter for tones and for speech, which tests a phonetic aspect of hearing. METHOD: Eight persons who stutter (PWS) were closely matched with eight controls (PNS) in terms of phonological abilities, verbal span tasks, age, sex and non-verbal intelligence. These participants were examined for their ability to recognize vowel-consonant (VC) speech syllables and tones in BM paradigm with 0 ms and 300 ms masker to signal onset conditions. RESULTS: PWS showed significantly poorer performance for speech syllable recognition in quiet and in conditions with masking noise. The pattern of speech errors was similar in both groups, but the PWS produced more errors. A significant condition by group interaction in backward masking for tones was attributed to higher masked thresholds in PWS than in PNS in the 0 ms delay condition for BM for tones. CONCLUSION: This was the first study to examine BM for speech in PWS. Results provide support for a small auditory-perceptual deficit for speech understanding in adults who stutter that was revealed in the absence of a lexical context. The speech results are explained in terms of possible indistinct phoneme boundaries in PWS and the effects of vowel context in speech recognition.

Cortical associates of emotional reactivity and regulation in childhood stuttering.

PURPOSE: This study sought to determine the cortical associates of emotional reactivity and emotion regulation (as indexed by the amplitude of evoked response potentials [ERP]) in young children who do and do not stutter during passive viewing of pleasant, unpleasant and neutral pictures. METHOD: Participants were 17 young children who stutter and 22 young children who do not stutter (between 4 years 0 months to 6 years 11 months). The dependent measures were (1) mean amplitude of late positive potential (LPP, an ERP sensitive to emotional stimuli) during passive (i.e., no response required) picture viewing and directed reappraisal tasks and (2) emotional reactivity and regulation related scores on caregiver reports of young children's temperament (Children's Behavior Questionnaire, CBQ). RESULTS: Young CWS, when compared to CWNS, exhibited significantly greater LPP amplitudes when viewing unpleasant pictures, but no significant between-group difference when viewing pleasant pictures and during the emotion regulation condition. There were, however, for CWS, but not CWNS, significant correlations between temperament-related measures of emotion and cortical measures of emotional reactivity and regulation. CONCLUSIONS: Findings provide further empirical support for the notion that emotional processes are associated with childhood stuttering, and that CWS's inherent temperamental proclivities need to be taken into account when empirically studying or theorizing about this association.

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

PURPOSE: Lack of social resources to support children who stutter may be due, in part, to the absence of epidemiological data regarding stuttering. This study investigated the proportion of three-year-old children who stutter in a city located in Hokkaido, a northern island of Japan. METHODS: The speech of individual children was assessed as part of a routine, government-conducted health care examination for 3-year-old children. The number of children screened was 2274, or 94.4% of all children in the city. The first author participated in the health care examination, and followed up all of the children who were found to stutter. RESULTS: At 3 years of age, 1.41% of the children exhibited stuttering; 82.8% of these children subsequently did not exhibit stuttering six months later. Boys were 1.57 times more likely to stutter than girls, but they had only 86% of the probability of reported or observed fluency seen in girls six months later. Significantly higher probability of later fluency was observed in children who exhibited normal, rather than delayed, language development at the 1.5-year health checkup preceding the 3-year health checkup. CONCLUSION: The proportion of three-year-old children who stutter and fluency status 6 months later are reported for a large cohort of Japanese children in Hokkaido. Language skills at 1;6 year may potentially be a factor in natural recovery or persistence; because of limitations in our study design, this assumption requires additional study. This is the first preliminary study to determine the proportion of three-year-old children who stutter in a Japanese community.

Comparison of adults who stutter with and without social anxiety disorder.

PURPOSE: Social anxiety disorder is a debilitating anxiety disorder associated with significant life impairment. The purpose of the present study is to evaluate overall functioning for adults who stutter with and without a diagnosis of social anxiety disorder. METHOD: Participants were 275 adults who stuttered (18-80 years), including 219 males (79.6%) and 56 females (20.4%), who were enrolled to commence speech treatment for stuttering. Comparisons were made between participants diagnosed with social anxiety disorder (n = 82, 29.8%) and those without that diagnosis (n = 193, 70.2%). RESULTS: Although the socially anxious group was significantly younger than the non-socially anxious group, no other demographic differences were found. When compared to the non-socially anxious group, the socially anxious group did not demonstrate significantly higher self-reported stuttering severity or percentage of syllables stuttered. Yet the socially anxious group reported more speech dissatisfaction and avoidance of speaking situations, significantly more psychological problems, and a greater negative impact of stuttering. CONCLUSION: Significant differences in speech and psychological variables between groups suggest that, despite not demonstrating more severe stuttering, socially anxious adults who stutter demonstrate more psychological difficulties and have a more negative view of their speech. The present findings suggest that the demographic status of adults who stutter is not worse for those with social anxiety disorder. These findings pertain to a clinical sample, and cannot be generalized to the wider population of adults who stutter from the general community. Further research is needed to understand the longer-term impact of social anxiety disorder for those who stutter.

Exogenously triggered response inhibition in developmental stuttering.

PURPOSE: The purpose of the present study was to examine relations between children's exogenously triggered response inhibition and stuttering. METHOD: Participants were 18 children who stutter (CWS; mean age = 9;01 years) and 18 children who not stutter (CWNS; mean age = 9;01 years). Participants were matched on age (±3 months) and gender. Response inhibition was assessed by a stop signal task (Verbruggen, Logan, & Stevens, 2008). RESULTS: Results suggest that CWS, compared to CWNS, perform comparable to CWNS in a task where response control is externally triggered. CONCLUSIONS: Our findings seem to indicate that previous questionnaire-based findings (Eggers, De Nil, & Van den Bergh, 2010) of a decreased efficiency of response inhibition cannot be generalized to all types of response inhibition.

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

PURPOSE: This study investigated the possible association of emotional processes and articulation rate in pre-school age children who stutter and persist (persisting), children who stutter and recover (recovered) and children who do not stutter (nonstuttering). METHODS: The participants were ten persisting, ten recovered, and ten nonstuttering children between the ages of 3-5 years; who were classified as persisting, recovered, or nonstuttering approximately 2-2.5 years after the experimental testing took place. The children were exposed to three emotionally-arousing video clips (baseline, positive and negative) and produced a narrative based on a text-free storybook following each video clip. From the audio-recordings of these narratives, individual utterances were transcribed and articulation rates were calculated. RESULTS: Results indicated that persisting children exhibited significantly slower articulation rates following the negative emotion condition, unlike recovered and nonstuttering children whose articulation rates were not affected by either of the two emotion-inducing conditions. Moreover, all stuttering children displayed faster rates during fluent compared to stuttered speech; however, the recovered children were significantly faster than the persisting children during fluent speech. CONCLUSION: Negative emotion plays a detrimental role on the speech-motor control processes of children who persist, whereas children who eventually recover seem to exhibit a relatively more stable and mature speech-motor system. This suggests that complex interactions between speech-motor and emotional processes are at play in stuttering recovery and persistency; and articulation rates following negative emotion or during stuttered versus fluent speech might be considered as potential factors to prospectively predict persistence and recovery from stuttering.

Anomalous network architecture of the resting brain in children who stutter.

PURPOSE: We combined a large longitudinal neuroimaging dataset that includes children who do and do not stutter and a whole-brain network analysis in order to examine the intra- and inter-network connectivity changes associated with stuttering. Additionally, we asked whether whole brain connectivity patterns observed at the initial year of scanning could predict persistent stuttering in later years. METHODS: A total of 224 high-quality resting state fMRI scans collected from 84 children (42 stuttering, 42 controls) were entered into an independent component analysis (ICA), yielding a number of distinct network connectivity maps ("components") as well as expression scores for each component that quantified the degree to which it is expressed for each child. These expression scores were compared between stuttering and control groups' first scans. In a second analysis, we examined whether the components that were most predictive of stuttering status also predicted persistence in stuttering. RESULTS: Stuttering status, as well as stuttering persistence, were associated with aberrant network connectivity involving the default mode network and its connectivity with attention, somatomotor, and frontoparietal networks. The results suggest developmental alterations in the balance of integration and segregation of large-scale neural networks that support proficient task performance including fluent speech motor control. CONCLUSIONS: This study supports the view that stuttering is a complex neurodevelopmental disorder and provides comprehensive brain network maps that substantiate past theories emphasizing the importance of considering situational, emotional, attentional and linguistic factors in explaining the basis for stuttering onset, persistence, and recovery.

Self-stigma and its associations with stress, physical health, and health care satisfaction in adults who stutter.

PURPOSE: The aim of this study was to identify potential relationships between self-stigma (stigma awareness and stigma application) and stress, physical health, and health care satisfaction among a large sample of adults who stutter. It was hypothesized that both stigma awareness and stigma application would be inversely related to measures of physical health and health care satisfaction, and positively related to stress. Furthermore, it was anticipated that stress mediated the relationship between self-stigma and physical health. METHOD: A sample of adults who stutter in the United States (n=397) completed a web survey that assessed levels of stigma awareness and stigma application, stress, physical health, and health care satisfaction. Correlational analyses were conducted to determine the relationships between these variables. RESULTS: Higher levels of stigma awareness and stigma application were associated with increased stress, decreased overall physical health, and decreased health care satisfaction (i.e., discomfort obtaining health care due to stuttering, and adverse health care outcomes due to stuttering), and these relationships were statistically significant. Stress was identified as a mediator between stigma application and physical health. CONCLUSION: Because adults who stutter with higher levels of self-stigma are at risk for decreased physical health through increased stress, and lower satisfaction with their health care experiences as a result of stuttering, it is important for professionals to assess and manage self-stigma in clients who stutter. Self-stigma has implications for not only psychological well-being, but stress, physical health, and health care satisfaction as well.

A case of multiple system atrophy-parkinsonian type with stuttering- and palilalia-like dysfluencies and putaminal atrophy.

Both developmental and acquired stuttering are related to the function of the basal ganglia-thalamocortical loop, which includes the putamen. Here, we present a case of stuttering- and palilalia-like dysfluencies that manifested as an early symptom of multiple system atrophy-parkinsonian type (MSA-P) and bilateral atrophy of the putamen. The patient was a 72-year-old man with no history of developmental stuttering who presented with a stutter for consultation with our otorhinolaryngology department. The patient was diagnosed with MSA-P based on parkinsonism, autonomic dysfunction, and bilateral putaminal atrophy revealed by T2-weighted magnetic resonance imaging. Treatment with levodopa improved both the motor functional deficits related to MSA-P and stuttering-like dysfluencies while reading; however, the palilalia-like dysfluencies were much less responsive to levodopa therapy. The patient died of aspiration pneumonia two years after his first consultation at our hospital. In conclusion, adult-onset stuttering- and palilalia-like dysfluencies warrant careful examination of the basal ganglia-thalamocortical loop, and especially the putamen, using neuroimaging techniques. Acquired stuttering may be related to deficits in dopaminergic function.