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.

Localization of stuttering based on causal brain lesions.

Stuttering affects approximately 1 in 100 adults and can result in significant communication problems and social anxiety. It most often occurs as a developmental disorder but can also be caused by focal brain damage. These latter cases may lend unique insight into the brain regions causing stuttering. Here, we investigated the neuroanatomical substrate of stuttering using three independent datasets: (i) case reports from the published literature of acquired neurogenic stuttering following stroke (n = 20, 14 males/six females, 16-77 years); (ii) a clinical single study cohort with acquired neurogenic stuttering following stroke (n = 20, 13 males/seven females, 45-87 years); and (iii) adults with persistent developmental stuttering (n = 20, 14 males/six females, 18-43 years). We used the first two datasets and lesion network mapping to test whether lesions causing acquired stuttering map to a common brain network. We then used the third dataset to test whether this lesion-based network was relevant to developmental stuttering. In our literature dataset, we found that lesions causing stuttering occurred in multiple heterogeneous brain regions, but these lesion locations were all functionally connected to a common network centred around the left putamen, including the claustrum, amygdalostriatal transition area and other adjacent areas. This finding was shown to be specific for stuttering (PFWE < 0.05) and reproducible in our independent clinical cohort of patients with stroke-induced stuttering (PFWE < 0.05), resulting in a common acquired stuttering network across both stroke datasets. Within the common acquired stuttering network, we found a significant association between grey matter volume and stuttering impact for adults with persistent developmental stuttering in the left posteroventral putamen, extending into the adjacent claustrum and amygdalostriatal transition area (PFWE < 0.05). We conclude that lesions causing acquired neurogenic stuttering map to a common brain network, centred to the left putamen, claustrum and amygdalostriatal transition area. The association of this lesion-based network with symptom severity in developmental stuttering suggests a shared neuroanatomy across aetiologies.

Functional and structural abnormalities of the speech disorders: a multimodal activation likelihood estimation meta-analysis.

Speech disorders are associated with different degrees of functional and structural abnormalities. However, the abnormalities associated with specific disorders, and the common abnormalities shown by all disorders, remain unclear. Herein, a meta-analysis was conducted to integrate the results of 70 studies that compared 1843 speech disorder patients (dysarthria, dysphonia, stuttering, and aphasia) to 1950 healthy controls in terms of brain activity, functional connectivity, gray matter, and white matter fractional anisotropy. The analysis revealed that compared to controls, the dysarthria group showed higher activity in the left superior temporal gyrus and lower activity in the left postcentral gyrus. The dysphonia group had higher activity in the right precentral and postcentral gyrus. The stuttering group had higher activity in the right inferior frontal gyrus and lower activity in the left inferior frontal gyrus. The aphasia group showed lower activity in the bilateral anterior cingulate gyrus and left superior frontal gyrus. Across the four disorders, there were concurrent lower activity, gray matter, and fractional anisotropy in motor and auditory cortices, and stronger connectivity between the default mode network and frontoparietal network. These findings enhance our understanding of the neural basis of speech disorders, potentially aiding clinical diagnosis and intervention.

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.

Stuttering in adolescence and the risk for dysglycemia in early adulthood.

AIMS: To investigate the association between stuttering during adolescence and the onset of dysglycemia (prediabetes or type 2 diabetes) in early adulthood among men and women. MATERIALS AND METHODS: This cohort study included Maccabi Health Services members assessed for mandatory military service at ages 16-19 during 1990-2019 and followed until 31 December 2020. Stuttering status was recorded in the baseline medical evaluation. Incident cases of dysglycemia were identified systematically using prediabetes and diabetes registries. Cox proportional hazard models were applied for men and women separately, adjusting for sociodemographics and medical status. RESULTS: The study cohort comprised 866,304 individuals (55% men; 0.21% with stuttering) followed for a total of 12,696,250 person-years. During the study period, 7.6% (n = 36,603) of men and 9.0% (n = 34,723) of women were diagnosed with dysglycemia. The mean ages at diagnosis were 34 and 32 years for men and women, respectively. Women with stuttering exhibited the highest dysglycemia incidence rate (102.3 per 10,000 person-years) compared with the other groups (61.4, 69.0, and 51.9 per 10,000 person-years for women without stuttering, men with stuttering, and men without stuttering, respectively). For both men and women, those with stuttering showed an increased risk of being diagnosed with dysglycemia compared with those without (adjusted hazard ratios 1.18 [1.01-1.38] and 1.61 [1.15-2.26], respectively). The associations persisted in extensive sub-analyses. CONCLUSIONS: Stuttering in adolescence is associated with a higher risk of dysglycemia in early adulthood for men and women. Screening and targeted prevention in this population, especially women, may be beneficial.

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.

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.

Inefficient speech-motor control affects predictive speech comprehension: atypical electrophysiological correlates in stuttering.

Listeners predict upcoming information during language comprehension. However, how this ability is implemented is still largely unknown. Here, we tested the hypothesis proposing that language production mechanisms have a role in prediction. We studied 2 electroencephalographic correlates of predictability during speech comprehension-pre-target alpha-beta (8-30 Hz) power decrease and the post-target N400 event-related potential effect-in a population with impaired speech-motor control, i.e. adults who stutter (AWS), compared to typically fluent adults (TFA). Participants listened to sentences that could either constrain towards a target word or not, modulating its predictability. As a complementary task, participants also performed context-driven word production. Compared to TFA, AWS not only displayed atypical neural responses in production, but, critically, they showed a different pattern also in comprehension. Specifically, while TFA showed the expected pre-target power decrease, AWS showed a power increase in frontal regions, associated with speech-motor control. In addition, the post-target N400 effect was reduced for AWS with respect to TFA. Finally, we found that production and comprehension power changes were positively correlated in TFA, but not in AWS. Overall, the results support the idea that processes and neural structures prominently devoted to speech planning also support prediction during speech comprehension.

Mothers' and fathers' attitudes toward stuttering in the Middle East compared to Europe and North America.

BACKGROUND: Parents play a central role in the treatment of childhood stuttering. Addressing parental attitudes toward stuttering is helpful therapeutically. The extent to which differences in attitudes toward stuttering exist on the basis of sex, geographical region and parental status (e.g., parent of a stuttering child, parent of a nonstuttering child, nonparent) is unclear. Many studies investigating such factors have used the Public Opinion Survey of Human Attributes-Stuttering (POSHA-S) questionnaire. A large POSHA-S database has collected responses from over 20 000 people from 49 countries. AIMS: The aim of this study was to use the POSHA-S database to examine the extent to which the following variables influence attitudes toward stuttering: (a) parents' sex (mothers vs. fathers), (b) geographic region (Middle East vs. Europe and North America), (c) parents' children (stuttering vs. nonstuttering) and (d) parental status (parents versus nonparents). METHODS & PROCEDURES: Data used in this study were extracted from selected, relevant studies that administered the POSHA-S to respondents. The Overall Stuttering Scores were compared on the basis of sex and parent status (i.e., mothers and fathers; nonparent women and men) and were then compared within and across the two geographical areas. Group comparisons were performed using analysis of variance followed by independent t tests, and Cohen's d was calculated to determine effect sizes. OUTCOMES & RESULTS: Statistically significant differences were observed upon the basis of geographical region. In general, male parents and nonparents tend to have more positive stuttering attitudes among the Middle Eastern samples while female parents and nonparents tend to show more positive attitudes in European and North American samples in the POSHA-S database. Effect sizes were small for all comparisons. CONCLUSIONS & IMPLICATIONS: The effect of geographic region and culture may predict sex-based differences among mothers' and fathers' attitudes toward stuttering; however, the clinical significance is unclear. Additional research is needed to better understand how children who stutter are affected by their parents' attitudes toward stuttering. WHAT THIS PAPER ADDS: What is already known on this subject The research clearly indicates that attitudes toward stuttering vary according to geographical region. Less clear is whether mothers and fathers from geographically diverse backgrounds hold different attitudes toward stuttering and the extent to which parental status (being a parent, parent of a child who stutters or nonparent) affects attitudes toward stuttering. What this study adds This study's findings confirm that geographical differences do influence attitudes toward stuttering. Male parents and nonparents tend to have equal or more positive attitudes toward stuttering in Middle Eastern samples, whereas non-Middle Eastern female parents and nonparents tend to show hold more positive attitudes. What are the clinical implications of this work? In addition to being culturally sensitive when working with parents of children who stutter, clinicians should also consider that mothers and fathers may have some differences in attitudes and behaviours toward their child's stuttering. These differences should be considered when designing treatment plans. It should also be noted that, despite statistical significance, the effect sizes in this study were low, suggesting that further research as well as close collaboration with parents of children who stutter is warranted.

Exploring participatory health research and its application to speech and language therapy research practices.

BACKGROUND: The role of participatory health research (PHR) is increasingly acknowledged by funding bodies, researchers and civil society globally; however, it continues to be under-represented in the speech and language therapy (SLT) research literature. This collaborative research approach is associated with the increased application of research evidence, and the generation of positive impacts in practice, policy, health systems and society. AIMS: To increase researchers' and other participatory partners' understanding of PHR, and to demonstrate its applicability to research in the SLT field. METHODS & PROCEDURES: This aim is achieved through a discussion on PHR, its principles, benefits and challenges, and the evaluation of its impact. A recently developed evaluation framework to support the implementation of best engagement practices is examined, and recommendations for how this framework can be used to plan and evaluate engagement in participatory stuttering research is presented. MAIN CONTRIBUTION: This paper serves as an important conversation on the value of PHR to SLT research, and presents guidance to support its increased implementation in this research field. CONCLUSIONS & IMPLICATIONS: Conclusions & Implications: PHR remains an under-represented research approach in the SLT literature, despite increasing evidence demonstrating its effectiveness and value. It offers a potential solution to the research-practice gap, and challenges the ongoing research hierarchies by democrating the process of knowledge production. WHAT THIS PAPER ADDS: What is already known on this subject PHR is increasingly attracting the attention of funders, researchers and decision-makers due to a growing body of evidence in support of this collaborative research approach. Despite its potential to bridge the research-practice gap, PHR remains significantly under-represented in the SLT research literature. What this paper adds to the existing knowledge This paper discusses the principles, benefits, challenges and impact evaluation of PHR. A recently developed evaluation framework for supporting the implementation of best engagement practices is examined. A demonstration of how this framework can be used to plan and evaluate engagement in participatory stuttering research is presented. What are the potential or actual clinical implications of this work? Speech and language therapists play a key role in PHR, as co-researchers contributing essential context-based knowledge. It is therefore imperative that they understand the principles and practices of this approach in order to maximize their input in future participatory partnerships.

Identification of the Biomechanical Response of the Muscles That Contract the Most during Disfluencies in Stuttered Speech.

Stuttering, affecting approximately 1% of the global population, is a complex speech disorder significantly impacting individuals' quality of life. Prior studies using electromyography (EMG) to examine orofacial muscle activity in stuttering have presented mixed results, highlighting the variability in neuromuscular responses during stuttering episodes. Fifty-five participants with stuttering and 30 individuals without stuttering, aged between 18 and 40, participated in the study. EMG signals from five facial and cervical muscles were recorded during speech tasks and analyzed for mean amplitude and frequency activity in the 5-15 Hz range to identify significant differences. Upon analysis of the 5-15 Hz frequency range, a higher average amplitude was observed in the zygomaticus major muscle for participants while stuttering (p < 0.05). Additionally, when assessing the overall EMG signal amplitude, a higher average amplitude was observed in samples obtained from disfluencies in participants who did not stutter, particularly in the depressor anguli oris muscle (p < 0.05). Significant differences in muscle activity were observed between the two groups, particularly in the depressor anguli oris and zygomaticus major muscles. These results suggest that the underlying neuromuscular mechanisms of stuttering might involve subtle aspects of timing and coordination in muscle activation. Therefore, these findings may contribute to the field of biosensors by providing valuable perspectives on neuromuscular mechanisms and the relevance of electromyography in stuttering research. Further research in this area has the potential to advance the development of biosensor technology for language-related applications and therapeutic interventions in stuttering.

Screening for Speech and Language Delay and Disorders in Children 5 Years or Younger: Evidence Report and Systematic Review for the US Preventive Services Task Force.

Importance: Children with speech and language difficulties are at risk for learning and behavioral problems. Objective: To review the evidence on screening for speech and language delay or disorders in children 5 years or younger to inform the US Preventive Services Task Force. Data Sources: PubMed/MEDLINE, Cochrane Library, PsycInfo, ERIC, Linguistic and Language Behavior Abstracts (ProQuest), and trial registries through January 17, 2023; surveillance through November 24, 2023. Study Selection: English-language studies of screening test accuracy, trials or cohort studies comparing screening vs no screening; randomized clinical trials (RCTs) of interventions. Data Extraction and Synthesis: Dual review of abstracts, full-text articles, study quality, and data extraction; results were narratively summarized. Main Outcomes and Measures: Screening test accuracy, speech and language outcomes, school performance, function, quality of life, and harms. Results: Thirty-eight studies in 41 articles were included (N = 9006). No study evaluated the direct benefits of screening vs no screening. Twenty-one studies (n = 7489) assessed the accuracy of 23 different screening tools that varied with regard to whether they were designed to be completed by parents vs trained examiners, and to screen for global (any) language problems vs specific skills (eg, expressive language). Three studies assessing parent-reported tools for expressive language skills found consistently high sensitivity (range, 88%-93%) and specificity (range, 88%-85%). The accuracy of other screening tools varied widely. Seventeen RCTs (n = 1517) evaluated interventions for speech and language delay or disorders, although none enrolled children identified by routine screening in primary care. Two RCTs evaluating relatively intensive parental group training interventions (11 sessions) found benefit for different measures of expressive language skills, and 1 evaluating a less intensive intervention (6 sessions) found no difference between groups for any outcome. Two RCTs (n = 76) evaluating the Lidcombe Program of Early Stuttering Intervention delivered by speech-language pathologists featuring parent training found a 2.3% to 3.0% lower proportion of syllables stuttered at 9 months compared with the control group when delivered in clinic and via telehealth, respectively. Evidence on other interventions was limited. No RCTs reported on the harms of interventions. Conclusions and Relevance: No studies directly assessed the benefits and harms of screening. Some parent-reported screening tools for expressive language skills had reasonable accuracy for detecting expressive language delay. Group parent training programs for speech delay that provided at least 11 parental training sessions improved expressive language skills, and a stuttering intervention delivered by speech-language pathologists reduced stuttering frequency.

Awareness and Knowledge of Stuttering among Malaysian School-Aged Children: An Exploratory Study.

INTRODUCTION: Knowledge and awareness of stuttering are closely associated with attitudes toward stuttering. Few studies have been conducted on the knowledge and awareness of school-aged children, and none have been conducted in Malaysia. This study aimed to: (a) determine knowledge and awareness of stuttering among Malaysian school-aged children, and (b) determine whether there are differences between age group, gender, and people who stutter (PWS) exposure groups. METHODS: A cross-sectional study was conducted among 192 Malay school-aged children (mean age = 9.47, SD = 1.781) recruited via email and social media platforms. They completed a Malay version of the questionnaire devised by van Borsel et al. (1999) on various aspects of stuttering, including prevalence, onset, gender distribution, occurrence in different cultures, cause, treatment, intelligence, and heredity of stuttering. The χ2 test of independence was performed to compare the distributions of survey responses by age group, gender, and PWS exposure group. RESULTS: Around half of the school-aged children had met a person who stutters, but certain aspects of their knowledge were limited. Knowledge also differed according to age and gender. Girls were more knowledgeable about stuttering than boys. Regarding stuttering treatment, younger children had more positive attitudes than older children. Participants who did not know a PWS were more likely to consult their family doctor rather than a speech-language pathologist in relation to stuttering. CONCLUSION: Knowledge and awareness of stuttering among Malaysian school-aged children were limited. Findings of this study could be used to develop a stuttering awareness program specific to children to increase their knowledge and awareness about stuttering.

Adaptation and Validation of Overall Assessment of the Speaker's Experience of Stuttering for Adults in Kannada (OASES-A-K).

INTRODUCTION: Psychosocial aspects of stuttering may affect the quality of life of a person who stutters (PWS). Further, the social stigma and experiences of PWS may vary globally. The WHO-ICF guidelines recommend quality of life as an essential component in the assessment of individuals who stutter. However, the availability of linguistically and culturally appropriate tools is often a challenge. Thus, the current study adapted and validated the OASES-A for Kannada-speaking adults who stutter. METHOD: The original English version of OASES-A was adapted to Kannada using a standard reverse translation process. The adapted version was administered on 51 Kannada-speaking adults with very mild to very severe stuttering. The data were analyzed for item characteristics, reliability, and validity assessment. RESULTS: The results revealed floor and ceiling effects for six and two items, respectively. The mean overall impact score indicated a moderate impact of stuttering. Further, the impact score for section II was relatively higher when compared to the data from other countries. The reliability and validity analyses showed good internal consistency and test-retest reliability for OASES-A-K. CONCLUSION: The findings of the current research suggest that OASES-A-K is a sensitive and reliable tool to assess the impact of stuttering in Kannada-speaking PWS. The findings also highlight cross-cultural differences and the need for research in this direction.

Attitudes of Malaysian Speech-Language Pathologists and Speech-Language Pathology Students toward Stuttering.

INTRODUCTION: Attitudes of speech-language pathologists (SLPs) toward stuttering play an important role in managing stuttering cases. Yet, such studies had not been studied in Malaysia, a country that is still developing the profession of speech-language pathology. This study aimed to explore the attitudes of Malaysian SLPs and speech-language pathology students toward stuttering. METHODS: A total of 50 SLPs and 67 speech-language pathology students completed the Clinician Attitudes Toward Stuttering (CATS) inventory. There were eight domains of attitudes toward stuttering: (a) etiology, (b) early intervention, (c) therapeutic efficacy, (d) personalities of people who stutter (PWS), (e) clinician expertise and roles, (f) teacher/counsellor roles and client/public reactions, (g) therapy strategies, and (h) parent attitudes. Descriptive data were presented, and multivariate analysis of variance was conducted to examine the effects of clinical certification on the eight domains of attitudes toward stuttering. RESULTS: Participants who possessed a clinical certification were more accepting toward the personalities of PWS and therapy strategies. On the other hand, participants without a clinical certification were more accepting toward clinician expertise and roles. CONCLUSIONS: Current curriculum and professional training should be reevaluated to remediate less accepting stereotypes held by SLPs and students toward PWS and to enhance essential skills such as counseling.

Self-reported musculoskeletal pain, headache, jaw pain and swallowing dysfunction in a sample of young Saudi adults who stutter.

Objectives: To report the prevalence of musculoskeletal pain, headache, jaw pain and difficulty in swallowing among people who stutter (PWS). METHODS: The cross-sectioal study was conducted from October 3, 2021, to March 21, 2022, after approval from the ethics review committee of King Khalid University, Abha, Saudi Arabia, and comprised adult people who stutter belonging to different regions of Saudi Arabia. They were divided into five groups based on stuttering severity as estimated by Stuttering Severity Instrument-4. Data was collected on musculoskeletal pain in different body areas using a questionnaire.. Data ws analysed using SPSS 22. RESULTS: Of the 101 Arabic-speaking subjects, 63(62.4%) were males and 38(37.6%) were females. The overall mean age was 27±7 years (range: 18-39 years). The largest group was of subjects with moderate severity of stuttering 31(30.6%); 21(68%) males and 10(32%) females. The increase in number of musculoskeletal pain locations was related to the severity of stuttering (p<0.05). The most common musculoskeletal pain sites were the lower back 31(31%), neck 26(26%) and shoulder 26(26%). Frequent headaches and difficulty chewing hard food due to jaw pain were reported by 49(49%) and 22(22%) participants, respectively (p<0.05). Swallowing difficulty was reported by 9(9%) participants (p>0.05). CONCLUSIONS: Widespread chronic musculoskeletal pain of low intensity was found to be common among people who stuttered, and the number of pain locations was positively related to stuttering severity.

Korean listeners' identification and discrimination of lengthened /s/ as prolongations.

This study aimed to examine Korean listeners' judgement of sound duration as prolongation and the mode of perceiving prolongation, whether discrete or continuous. A total of 75 Korean undergraduate students listened to the Korean segment /s/, each of which was lengthened by 0-380 ms (ranging from the original 205 to 585 ms) in 20-ms increments. Then, the participants were asked to complete two different primary tasks: determine whether the sound was normal (0) or abnormal (1) and rate each version of the sound based on a rating of 1 to 100 (the closer to 100, the less fluent). The minimum duration for the Korean sound to be perceived as abnormally prolonged was calculated by analysing the receiver operating characteristic (ROC) curves using Youden's index. To examine whether listeners perceived durational variations for the fricative segment discretely or continuously, a curve was estimated using the best fitting regression model for the observed data with the highest adjusted R-squared value. The minimum duration identified as abnormal prolongation for the Korean lenis fricative /s/ was 375 ms, corresponding to 182.9% of the original, unaltered sound's length. The mode of perceiving durational variations for the segment was continuous (or gradient) rather than discrete. No gender difference was found in the minimum durational threshold and the mode of perceiving prolongation. The findings of this study were further discussed in relation to the existing body of research, and some clinical implications for the assessment of stuttering were also presented.

Linguistic disfluencies in Russian-speaking typically and atypically developing children: individual variability in different contexts.

Disfluency in children and adults seems to occur like errors of speech but, at the same time, is an essential feature of spontaneous (unprepared) speech. The present study aimed to evaluate linguistic disfluencies in typically and atypically developing Russian-speaking children from the perspective of the dynamic adaptive model of self-monitoring in speech production. The study collected four language samples from 10 six-year-old children with developmental language disorder and 14 typically developing peers: two storytelling tasks, structured conversation, and a play argument. After transcribing audio-recordings and marking linguistic disfluencies, the authors conducted structured distributional analysis. The distribution of several indexes of disfluency was estimated to assess the prevalence and profiles of different (sub)types of disfluencies. The disfluency rate statistics were similar between the typically developing children and children with developmental language disorder. The distributional indexes score showed that tasks significantly impacted the rate of different (sub)types of disfluencies. Task-related patterns in a set of the distributional indexes significantly distinguished the groups. Thus, changes in the disfluency profile related to different external factors, as a sign of a flexibility of an adaptive self-monitoring system, may be limited in children with developmental language disorder.

Syllable- and word-based measures of stuttering in speech samples of Turkish-speaking school-aged children.

Linguistic factors influence the likelihood of occurrence of stuttering instances on a certain word within an utterance. However, studies on the relationship between stuttering instances and linguistic factors of Turkish-speaking individuals are scarce. This study aimed to determine the syllable- and word-based measures of stuttering speech samples of Turkish-speaking school-aged children who stutter. Stuttering-like disfluencies (SLDs) and lexical categories were identified after transcription of 61 children's spontaneous speech samples (age range = 6-16). Syllable-, word- and utterance-level measures were employed. Syllable-based and word-based stuttering frequency findings were significantly different (p < .001); SLDs were more likely to occur at the utterance-initial (p < .001) and word-initial (p < .001) positions; content words were more likely to be stuttered and, there was a relation between the occurrence of SLDs and utterance length (p = .001). Since there is great variability between word-based and syllable-based measures, and SLDs tend to occur at word onsets, using word-based measures in Turkish would provide a measure of stuttering frequency that is comparable to the literature. Moreover, findings support that phrases requiring greater demands on utterance planning increase the possibility of occurrence of stuttering instances.

Stuttering as a signal of encephalopathy associated with toripalimab in a pancreatic ductal adenocarcinoma patient: a case report.

BACKGROUND: Immune checkpoint inhibitor (ICI) combined with chemotherapy has exhibited promising results in small sample studies of pancreatic cancer patients. The efficacy of toripalimab, a programmed cell death protein 1 (PD-1) monoclonal antibody has been explored in the previous studies and it was established that immune-related adverse events (irAEs) associated with administration of this drug deserve proper attention and adequate management. CASE PRESENTATION: A 43-year-old female patient with advanced pancreatic ductal adenocarcinoma (PDAC) was treated with toripalimab in combination with gemcitabine and nab-paclitaxel (T-GA) as the first-line treatment. She developed immune-related encephalopathy with stuttering as the main clinical symptom and Magnetic resonance imaging (MRI) showed multiple cerebral white matter demyelination changes, concomitant with asymptomatic cardiac enzyme elevation and hypothyroidism. The symptoms resolved after the discontinuation of toripalimab and corticosteroid treatment. CONCLUSIONS: Stuttering might be an early sign of neurotoxicity which can be easily neglected during the treatment. These findings provide guidance for the identification of these rare and occult neurological irAEs (n-irAEs) in the clinical practice.