Atypical development of Broca's area in a large family with inherited stuttering

Lidcombe Program telehealth treatment for children 6-12 years of age: A Phase II trial

BACKGROUND

For children older than 6 years who stutter, there is a gap in clinical research. This is an issue for speech-language pathologists because the tractability of stuttering decreases and the risk of long-term psychological consequences increase with age.

PURPOSE

To report a Phase II trial of a telehealth version of the Lidcombe Program with school-age children.

METHODS

Participants were 37 children who stuttered, 6-12 years of age, from Australia, New Zealand, Hong Kong, and Singapore. Parents were trained by video telehealth how to deliver the Lidcombe Program to their child. Primary and secondary outcomes were stuttering severity and psychosocial functioning measured pre-treatment and at 6 months and 12 months after starting treatment. Parents submitted two 10-minute recordings of their child speaking in conversation, and three measures of anxiety, impact of stuttering, and communication attitude.

RESULTS

Six months after starting treatment, seven children (18.9%) attained Lidcombe Program Stage 2 criteria, 25 children (67.6%) showed a partial response to treatment, and five children (13.5%) showed no response. By 12 months, 12 children (32.4%) had reached Stage 2 criteria. Psychosocial improvements were observed 6 and 12 months after starting treatment.

CONCLUSIONS

The Lidcombe Program may eliminate or nearly eliminate stuttering for about one third of children 6-12 years of age. Randomized controlled trials with this age group involving the Lidcombe Program are warranted. In the interim, the Lidcombe Program is a clinical option clinicians can implement with this age group to reduce stuttering and its psychosocial impacts.

The clinical and genetic spectrum of paediatric speech and language disorders in 52,143 individuals

Speech and language disorders are known to have a substantial genetic contribution. Although frequently examined as components of other conditions, research on the genetic basis of linguistic differences as separate phenotypic subgroups has been limited so far. Here, we performed an in-depth characterization of speech and language disorders in 52,143 individuals, reconstructing clinical histories using a large-scale data mining approach of the Electronic Medical Records (EMR) from an entire large paediatric healthcare network. The reported frequency of these disorders was the highest between 2 and 5 years old and spanned a spectrum of twenty-six broad speech and language diagnoses. We used Natural Language Processing to assess to which degree clinical diagnosis in full-text notes were reflected in ICD-10 diagnosis codes. We found that aphasia and speech apraxia could be easily retrieved through ICD-10 diagnosis codes, while stuttering as a speech phenotype was only coded in 12% of individuals through appropriate ICD-10 codes. We found significant comorbidity of speech and language disorders in neurodevelopmental conditions (30.31%) and to a lesser degree with epilepsies (6.07%) and movement disorders (2.05%). The most common genetic disorders retrievable in our EMR analysis were STXBP1 (n=21), PTEN (n=20), and CACNA1A (n=18). When assessing associations of genetic diagnoses with specific linguistic phenotypes, we observed associations of STXBP1 and aphasia (P=8.57 × 10-7, CI=18.62-130.39) and MYO7A with speech and language development delay due to hearing loss (P=1.24 × 10-5, CI=17.46-Inf). Finally, in a sub-cohort of 726 individuals with whole exome sequencing data, we identified an enrichment of rare variants in synaptic protein and neuronal receptor pathways and associations of UQCRC1 with expressive aphasia and WASHC4 with abnormality of speech or vocalization. In summary, our study outlines the landscape of paediatric speech and language disorders, confirming the phenotypic complexity of linguistic traits and novel genotype-phenotype associations. Subgroups of paediatric speech and language disorders differ significantly with respect to the composition of monogenic aetiologies.

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.

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.

New insights into the genetics of stuttering

This scientific commentary refers to ‘Stuttering associated with a pathogenic variant in the chaperone protein cyclophilin 40’ by Morgan et al. (https://doi.org/10.1093/brain/awad314).

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.

Epilepsy and Diagnostic Dilemmas: The Role of Language and Speech-Related Seizures

Although the impact of epilepsy on expressive language is heavily discussed, researched, and scientifically grounded, a limited volume of research points in the opposite direction. What about the causal relationship between disorder-related language activities and epileptic seizures? What are the possible diagnostic dilemmas that experts in the field of speech-language pathology, neurology, and related fields face? How far has research gone in investigating psychogenic nonepileptic seizures, the misdiagnosis of which can be a thorny issue for clinicians and a detrimental factor for the patients’ health? In order to address these questions, the study at hand focuses on a common, ever-intensified (by the COVID-19 pandemic) speech disorder—stuttering, and explores the pathophysiological and psychogenic background of the phenomenon. It also looks at the role of stuttering as a contributing factor to the appearance of epileptic seizures, in the hope of drawing attention to the complexity and importance of precise detection of stuttering-induced epilepsy, as a specific subcategory of language-induced epilepsy.