White matter pathways for prosodic structure building: A case study

Prosody Disorder and Sing-Song Speech in a Patient With Recurrent Glioblastoma: A Case Report

Dysprosody affects rhythm and intonation in speech, resulting in the impairment of emotional or attitude expression, and usually presents as a negative symptom resulting in a monotonous tone. We herein report a rare case of recurrent glioblastoma (GBM) with dysprosody featuring sing-song speech. A 68-year-old man, formerly left-handed, with right temporal GBM underwent gross total resection. After chemoradiation therapy, he was discharged without any deficits. Nineteen months later, the patient exhibited recurrence and presented a peculiar way of speaking with excessive melodic intonation. A head magnetic resonance imaging revealed new enhanced lesions in the residual right temporal lobe and the splenium of the corpus callosum with a massive surrounding T2-high area. The case highlights the bilateral hemispheric network underlying prosody and the compensatory failure caused by tumor progression and connectivity disruption. This first account of sing-song dysprosody in a GBM patient underscores the complexity of the language network and the need for further case accumulation to elucidate the pathophysiology of such rare presentations.

Neural Signature of Rhyming Ability During Story Listening in Preschool-Age Children

Purpose: Rhyming is a phonological skill that typically emerges in the preschool-age range. Prosody/rhythm processing involves right-lateralized temporal cortex, yet the neural basis of rhyming ability in young children is unclear. The study objective was to use functional magnetic resonance imaging (fMRI) to quantify neural correlates of rhyming abilities in preschool-age children. Method: Healthy pre-kindergarten child-parent dyads were recruited for a study visit including MRI and the Preschool and Primary Inventory of Phonological Awareness (PIPA) rhyme subtest. MRI included an fMRI task where the child listened to a rhymed and unrhymed story without visual stimuli. fMRI data were processed using the CONN functional connectivity (FC) toolbox, with FC computed between 132 regions of interest (ROI) across the brain. Associations between PIPA score and FC during the rhymed versus unrhymed story were compared accounting for age, sex, and maternal education. Results: In total, 45 children completed MRI (age 54 ± 8 months, 37-63; 19M 26F). Median maternal education was college graduate. FC between ROIs in posterior default mode (imagery) and right fronto-parietal (executive function) networks was more strongly positively associated with PIPA score during the rhymed compared with the unrhymed story [F(2,39) = 10.95, p-FDR = 0.043], as was FC between ROIs in right-sided language (prosody) and dorsal attention networks [F(2,39) = 9.85, p-FDR = 0.044]. Conclusions: Preschool-age children with better rhyming abilities had stronger FC between ROIs supporting attention and prosody and also between ROIs supporting executive function and imagery, suggesting rhyme as a catalyst for attention, visualization, and comprehension. These represent novel neural biomarkers of nascent phonological skills.

Event-related responses reflect chunk boundaries in natural speech

Chunking language has been proposed to be vital for comprehension enabling the extraction of meaning from a continuous stream of speech. However, neurocognitive mechanisms of chunking are poorly understood. The present study investigated neural correlates of chunk boundaries intuitively identified by listeners in natural speech drawn from linguistic corpora using magneto- and electroencephalography (MEEG). In a behavioral experiment, subjects marked chunk boundaries in the excerpts intuitively, which revealed highly consistent chunk boundary markings across the subjects. We next recorded brain activity to investigate whether chunk boundaries with high and medium agreement rates elicit distinct evoked responses compared to non-boundaries. Pauses placed at chunk boundaries elicited a closure positive shift with the sources over bilateral auditory cortices. In contrast, pauses placed within a chunk were perceived as interruptions and elicited a biphasic emitted potential with sources located in the bilateral primary and non-primary auditory areas with right-hemispheric dominance, and in the right inferior frontal cortex. Furthermore, pauses placed at stronger boundaries elicited earlier and more prominent activation over the left hemisphere suggesting that brain responses to chunk boundaries of natural speech can be modulated by the relative strength of different linguistic cues, such as syntactic structure and prosody.

Right ventral stream damage underlies both poststroke aprosodia and amusia

BACKGROUND AND PURPOSE

This study was undertaken to determine and compare lesion patterns and structural dysconnectivity underlying poststroke aprosodia and amusia, using a data-driven multimodal neuroimaging approach.

METHODS

Thirty-nine patients with right or left hemisphere stroke were enrolled in a cohort study and tested for linguistic and affective prosody perception and musical pitch and rhythm perception at subacute and 3-month poststroke stages. Participants listened to words spoken with different prosodic stress that changed their meaning, and to words spoken with six different emotions, and chose which meaning or emotion was expressed. In the music tasks, participants judged pairs of short melodies as the same or different in terms of pitch or rhythm. Structural magnetic resonance imaging data were acquired at both stages, and machine learning-based lesion-symptom mapping and deterministic tractography were used to identify lesion patterns and damaged white matter pathways giving rise to aprosodia and amusia.

RESULTS

Both aprosodia and amusia were behaviorally strongly correlated and associated with similar lesion patterns in right frontoinsular and striatal areas. In multiple regression models, reduced fractional anisotropy and lower tract volume of the right inferior fronto-occipital fasciculus were the strongest predictors for both disorders, over time.

CONCLUSIONS

These results highlight a common origin of aprosodia and amusia, both arising from damage and disconnection of the right ventral auditory stream integrating rhythmic-melodic acoustic information in prosody and music. Comorbidity of these disabilities may worsen the prognosis and affect rehabilitation success.

(Dys)Prosody in Parkinson's Disease: Effects of Medication and Disease Duration on Intonation and Prosodic Phrasing

The phonology of prosody has received little attention in studies of motor speech disorders. The present study investigates the phonology of intonation (nuclear contours) and speech chunking (prosodic phrasing) in Parkinson’s disease (PD) as a function of medication intake and duration of the disease. Following methods of the prosodic and intonational phonology frameworks, we examined the ability of 30 PD patients to use intonation categories and prosodic phrasing structures in ways similar to 20 healthy controls to convey similar meanings. Speech data from PD patients were collected before and after a dopaminomimetic drug intake and were phonologically analyzed in relation to nuclear contours and intonational phrasing. Besides medication, disease duration and the presence of motor fluctuations were also factors included in the analyses. Overall, PD patients showed a decreased ability to use nuclear contours and prosodic phrasing. Medication improved intonation regardless of disease duration but did not help with dysprosodic phrasing. In turn, disease duration and motor fluctuations affected phrasing patterns but had no impact on intonation. Our study demonstrated that the phonology of prosody is impaired in PD, and prosodic categories and structures may be differently affected, with implications for the understanding of PD neurophysiology and therapy.

Links of Prosodic Stress Perception and Musical Activities to Language Skills of Children With Cochlear Implants and Normal Hearing

OBJECTIVES

A major issue in the rehabilitation of children with cochlear implants (CIs) is unexplained variance in their language skills, where many of them lag behind children with normal hearing (NH). Here, we assess links between generative language skills and the perception of prosodic stress, and with musical and parental activities in children with CIs and NH. Understanding these links is expected to guide future research and toward supporting language development in children with a CI.

DESIGN

Twenty-one unilaterally and early-implanted children and 31 children with NH, aged 5 to 13, were classified as musically active or nonactive by a questionnaire recording regularity of musical activities, in particular singing, and reading and other activities shared with parents. Perception of word and sentence stress, performance in word finding, verbal intelligence (Wechsler Intelligence Scale for Children (WISC) vocabulary), and phonological awareness (production of rhymes) were measured in all children. Comparisons between children with a CI and NH were made against a subset of 21 of the children with NH who were matched to children with CIs by age, gender, socioeconomic background, and musical activity. Regression analyses, run separately for children with CIs and NH, assessed how much variance in each language task was shared with each of prosodic perception, the child's own music activity, and activities with parents, including singing and reading. All statistical analyses were conducted both with and without control for age and maternal education.

RESULTS

Musically active children with CIs performed similarly to NH controls in all language tasks, while those who were not musically active performed more poorly. Only musically nonactive children with CIs made more phonological and semantic errors in word finding than NH controls, and word finding correlated with other language skills. Regression analysis results for word finding and VIQ were similar for children with CIs and NH. These language skills shared considerable variance with the perception of prosodic stress and musical activities. When age and maternal education were controlled for, strong links remained between perception of prosodic stress and VIQ (shared variance: CI, 32%/NH, 16%) and between musical activities and word finding (shared variance: CI, 53%/NH, 20%). Links were always stronger for children with CIs, for whom better phonological awareness was also linked to improved stress perception and more musical activity, and parental activities altogether shared significantly variance with word finding and VIQ.

CONCLUSIONS

For children with CIs and NH, better perception of prosodic stress and musical activities with singing are associated with improved generative language skills. In addition, for children with CIs, parental singing has a stronger positive association to word finding and VIQ than parental reading. These results cannot address causality, but they suggest that good perception of prosodic stress, musical activities involving singing, and parental singing and reading may all be beneficial for word finding and other generative language skills in implanted children.

Language Without Speech: Segregating Distinct Circuits in the Human Brain

Language is a fundamental part of human cognition. The question of whether language is processed independently of speech, however, is still heavily discussed. The absence of speech in deaf signers offers the opportunity to disentangle language from speech in the human brain. Using probabilistic tractography, we compared brain structural connectivity of adult deaf signers who had learned sign language early in life to that of matched hearing controls. Quantitative comparison of the connectivity profiles revealed that the core language tracts did not differ between signers and controls, confirming that language is independent of speech. In contrast, pathways involved in the production and perception of speech displayed lower connectivity in deaf signers compared to hearing controls. These differences were located in tracts towards the left pre-supplementary motor area and the thalamus when seeding in Broca's area, and in ipsilateral parietal areas and the precuneus with seeds in left posterior temporal regions. Furthermore, the interhemispheric connectivity between the auditory cortices was lower in the deaf than in the hearing group, underlining the importance of the transcallosal connection for early auditory processes. The present results provide evidence for a functional segregation of the neural pathways for language and speech.

Intonation processing increases task-specific fronto-temporal connectivity in tonal language speakers

Language comprehension depends on tight functional interactions between distributed brain regions. While these interactions are established for semantic and syntactic processes, the functional network of speech intonation – the linguistic variation of pitch – has been scarcely defined. Particularly little is known about intonation in tonal languages, in which pitch not only serves intonation but also expresses meaning via lexical tones. The present study used psychophysiological interaction analyses of functional magnetic resonance imaging data to characterise the neural networks underlying intonation and tone processing in native Mandarin Chinese speakers. Participants categorised either intonation or tone of monosyllabic Mandarin words that gradually varied between statement and question and between Tone 2 and Tone 4. Intonation processing induced bilateral fronto‐temporal activity and increased functional connectivity between left inferior frontal gyrus and bilateral temporal regions, likely linking auditory perception and labelling of intonation categories in a phonological network. Tone processing induced bilateral temporal activity, associated with the auditory representation of tonal (phonemic) categories. Together, the present data demonstrate the breadth of the functional intonation network in a tonal language including higher‐level phonological processes in addition to auditory representations common to both intonation and tone.

Expectations about word stress modulate neural activity in speech-sensitive cortical areas

A recent dual-stream model of language processing proposed that the postero-dorsal stream performs predictive sequential processing of linguistic information via hierarchically organized internal models. However, it remains unexplored whether the prosodic segmentation of linguistic information involves predictive processes. Here, we addressed this question by investigating the processing of word stress, a major component of speech segmentation, using probabilistic repetition suppression (RS) modulation as a marker of predictive processing. In an event-related acoustic fMRI RS paradigm, we presented pairs of pseudowords having the same (Rep) or different (Alt) stress patterns, in blocks with varying Rep and Alt trial probabilities. We found that the BOLD signal was significantly lower for Rep than for Alt trials, indicating RS in the posterior and middle superior temporal gyrus (STG) bilaterally, and in the anterior STG in the left hemisphere. Importantly, the magnitude of RS was modulated by repetition probability in the posterior and middle STG. These results reveal the predictive processing of word stress in the STG areas and raise the possibility that words stress processing is related to the dorsal "where" auditory stream.

Neural correlates of intonation and lexical tone in tonal and non-tonal language speakers

Intonation, the modulation of pitch in speech, is a crucial aspect of language that is processed in right‐hemispheric regions, beyond the classical left‐hemispheric language system. Whether or not this notion generalises across languages remains, however, unclear. Particularly, tonal languages are an interesting test case because of the dual linguistic function of pitch that conveys lexical meaning in form of tone, in addition to intonation. To date, only few studies have explored how intonation is processed in tonal languages, how this compares to tone and between tonal and non‐tonal language speakers. The present fMRI study addressed these questions by testing Mandarin and German speakers with Mandarin material. Both groups categorised mono‐syllabic Mandarin words in terms of intonation, tone, and voice gender. Systematic comparisons of brain activity of the two groups between the three tasks showed large cross‐linguistic commonalities in the neural processing of intonation in left fronto‐parietal, right frontal, and bilateral cingulo‐opercular regions. These areas are associated with general phonological, specific prosodic, and controlled categorical decision‐making processes, respectively. Tone processing overlapped with intonation processing in left fronto‐parietal areas, in both groups, but evoked additional activity in bilateral temporo‐parietal semantic regions and subcortical areas in Mandarin speakers only. Together, these findings confirm cross‐linguistic commonalities in the neural implementation of intonation processing but dissociations for semantic processing of tone only in tonal language speakers.

Neural architectures of music - Insights from acquired amusia

The ability to perceive and produce music is a quintessential element of human life, present in all known cultures. Modern functional neuroimaging has revealed that music listening activates a large-scale bilateral network of cortical and subcortical regions in the healthy brain. Even the most accurate structural studies do not reveal which brain areas are critical and causally linked to music processing. Such questions may be answered by analysing the effects of focal brain lesions in patients´ ability to perceive music. In this sense, acquired amusia after stroke provides a unique opportunity to investigate the neural architectures crucial for normal music processing. Based on the first large-scale longitudinal studies on stroke-induced amusia using modern multi-modal magnetic resonance imaging (MRI) techniques, such as advanced lesion-symptom mapping, grey and white matter morphometry, tractography and functional connectivity, we discuss neural structures critical for music processing, consider music processing in light of the dual-stream model in the right hemisphere, and propose a neural model for acquired amusia.