1,720,996 research outputs found
Erratum to “Auditory brainstem measures and genotyping boost the prediction of literacy: A longitudinal study on early markers of dyslexia” [Dev. Cognit. Neurosci. 46 (2020) 100869]
No full textKnowns and unknowns about the neurobiology of stuttering.
No full textStuttering 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
Speech production in stuttering: Impact of syllable frequency and word length on accuracy and fluency
No full textStuttering severity relates to frontotemporal low-beta synchronization during pre-speech preparation
No full textSubject-specific Functional ROIs Enhance Reliability in Language FMRI
No full textAbstract Purpose Functional MRI can be used to identify individual language-sensitive brain regions in the setting of presurgical diagnostics to improve functional postoperative outcome. In this study, a proven language task was adapted into German and tested with regard to its effectiveness, robustness and reliability in a time frame appropriate for the clinical setting. In addition, two different analysis approaches were compared to address the problem of arbitrary statistical thresholds commonly used in the clinical routine to derive contrast maps. Methods On two different days, 24 healthy volunteers were examined in a 3T MRI, whereby the task was run twice in each session. The fMRI included two conditions in a block design, reading of sentences and reading of pronounceable nonword lists. We quantified brain activity by using subject-specific, functionally defined ROIs on the one hand and standardized, anatomically defined ROIs on the other. We then tested, whether the two different analyses indicated robust activation of language-sensitive brain regions, and whether effect sizes were reliable across sessions. Results Subject-specific functional ROIs as well as anatomical ROIs led to significant positive effect sizes in the major language sensitive regions of the left hemisphere. However, subject-specific functional ROIs resulted in significantly larger effect sizes and a higher reliability in comparison to anatomical ROIs. Conclusion The choice of analysis method has a significant impact on the result. For paradigms with short measurement times and little signal change as common in clinical routine, it is highly recommended to use the subject-specific functional ROIs approach
Editorial: The Neurophysiology of Developmental Stuttering: Unraveling the Mysteries of Fluency
No full textEnlarged Area of Mesencephalic Iron Deposits in Adults Who Stutter
No full textOpen-Access-Publikationsfonds 202
Dissecting structural connectivity of the left and right inferior frontal cortex in children who stutter
No full textInferior 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
Reduced Speech Perceptual Acuity for Stop Consonants in Individuals Who Stutter
No full textPurpose: In individuals who stutter (IWS), speech fluency can be enhanced by altered auditory feedback, although it has adverse effects in control speakers. This indicates abnormalities in the auditory feedback loop in stuttering. Current motor control theories on stuttering propose an impaired processing of internal forward models that might be related to a blurred auditory-to-motor translation. Although speech sound perception is an essential skill to form internal models, perceptual acuity has not been studied in IWS so far. The authors tested the stability of phoneme percepts by analyzing participants' ability to identify voiced and voiceless stop consonants. Method: Two syllable continua were generated by systematic modification of the voice onset time. The authors determined speech perceptual acuity by means of discriminatory power in 25 IWS and 24 matched control participants by determining the phoneme boundaries and by quantifying the interval of voice onset times for which phonemes were perceived ambiguously. Results: In IWS, discriminatory performance was weaker and less stable over time when compared with control participants. In addition, phoneme boundaries were located at longer voice onset times in IWS. Conclusion: Persistent developmental stuttering is associated with less reliable phonological percepts, supporting current theories regarding the sensory-motor interaction in human speech
Left posterior-dorsal area 44 couples with parietal areas to promote speech fluency, while right area 44 activity promotes the stopping of motor responses
Full text linkAbstractArea 44 is a cytoarchitectonically distinct portion of Broca's region. Parallel and overlapping large-scale networks couple with this region thereby orchestrating heterogeneous language, cognitive, and motor functions. In the context of stuttering, area 44 frequently comes into focus because structural and physiological irregularities affect developmental trajectories, stuttering severity, persistency, and etiology. A remarkable phenomenon accompanying stuttering is the preserved ability to sing. Speaking and singing are connatural behaviours recruiting largely overlapping brain networks including left and right area 44. Analysing which potential subregions of area 44 are malfunctioning in adults who stutter, and what effectively suppresses stuttering during singing, may provide a better understanding of the coordination and reorganization of large-scale brain networks dedicated to speaking and singing in general. We used fMRI to investigate functionally distinct subregions of area 44 during imagery of speaking and imaginary of humming a melody in 15 dextral males who stutter and 17 matched control participants. Our results are fourfold. First, stuttering was specifically linked to a reduced activation of left posterior-dorsal area 44, a subregion that is involved in speech production, including phonological word processing, pitch processing, working memory processes, sequencing, motor planning, pseudoword learning, and action inhibition. Second, functional coupling between left posterior area 44 and left inferior parietal lobule was deficient in stuttering. Third, despite the preserved ability to sing, males who stutter showed bilaterally a reduced activation of area 44 when imagine humming a melody, suggesting that this fluency-enhancing condition seems to bypass posterior-dorsal area 44 to achieve fluency. Fourth, time courses of the posterior subregions in area 44 showed delayed peak activations in the right hemisphere in both groups, possibly signaling the offset response. Because these offset response-related activations in the right hemisphere were comparably large in males who stutter, our data suggest a hyperactive mechanism to stop speech motor responses and thus possibly reflect a pathomechanism, which, until now, has been neglected. Overall, the current results confirmed a recently described co-activation based parcellation supporting the idea of functionally distinct subregions of left area 44
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