Age-related sex differences in language lateralization: A magnetoencephalography study in children

Effect of Age and Gender on Categorical Perception of Vocal Emotion Under Tonal Language Background

PURPOSE

Categorical perception (CP) manifests in various aspects of human cognition. While there is mounting evidence for CP in facial emotions, CP in vocal emotions remains understudied. The current study attempted to test whether individuals with a tonal language background perceive vocal emotions categorically and to examine how factors such as gender and age influence the plasticity of these perceptual categories.

METHOD

This study examined the identification and discrimination performance of 24 Mandarin-speaking children (14 boys and 10 girls) and 32 adults (16 males and 16 females) when they were presented with three vocal emotion continua. Speech stimuli in each continuum consisted of 11 resynthesized Mandarin disyllabic words.

RESULTS

CP phenomena were detected when Mandarin participants perceived vocal emotions. We further found the modulating effect of age and gender in vocal emotion categorization.

CONCLUSIONS

Our results demonstrate for the first time that a categorical strategy is used by Mandarin speakers when perceiving vocal emotions. Furthermore, our findings reveal that the categorization ability of vocal emotions follows a prolonged course of development and the maturation patterns differ across genders. This study opens a promising line of research for investigating how sensory features are mapped to higher order perception and provides implications for our understanding of clinical populations characterized by altered emotional processing.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.27204057.

Predicting cerebellar mutism syndrome in children using lesion map combined with clinical features

OBJECTIVE

This study aimed to develop a predictive model for cerebellar mutism syndrome (CMS) in pediatric patients with posterior fossa tumors, integrating lesion-symptom mapping (LSM) data with clinical factors, and to assess the model's performance.

METHODS

A cohort of pediatric patients diagnosed with posterior fossa tumors and undergoing surgery at Beijing Children's Hospital from July 2013 to December 2023 was analyzed. Clinical variables gender, age at surgery, tumor characteristics, hydrocephalus, surgical route and pathology were collected. LSM was used to link tumor locations with CMS outcomes. Lasso regression and logistic regression were employed for feature selection and model construction, respectively. Model performance was assessed using area under the curve (AUC) and accuracy metrics.

RESULTS

The study included 197 patients in total, with CMS rates consistent across training, validation, and prospective groups. Significant associations were found between CMS and gender, tumor type, hydrocephalus, paraventricular edema, surgical route, and pathology. A predictive model combining voxel location data from LSM with clinical factors achieved high predictive performance (C-index: training 0.956, validation 0.933, prospective 0.892). Gender, pathology, and voxel location were identified as key predictors for CMS.

CONCLUSION

The study established an effective predictive model for CMS in pediatric posterior fossa tumor patients, leveraging LSM data and clinical factors. The model's accuracy and robustness suggest its potential utility in clinical practice for early CMS risk assessment and intervention planning.

Maturation of auditory cortex neural responses during infancy and toddlerhood

The infant auditory system rapidly matures across the first years of life, with a primary goal of obtaining ever-more-accurate real-time representations of the external world. Our understanding of how left and right auditory cortex neural processes develop during infancy, however, is meager, with few studies having the statistical power to detect potential hemisphere and sex differences in primary/secondary auditory cortex maturation. Using infant magnetoencephalography (MEG) and a cross-sectional study design, left and right auditory cortex P2m responses to pure tones were examined in 114 typically developing infants and toddlers (66 males, 2 to 24 months). Non-linear maturation of P2m latency was observed, with P2m latencies decreasing rapidly as a function of age during the first year of life, followed by slower changes between 12 and 24 months. Whereas in younger infants auditory tones were encoded more slowly in the left than right hemisphere, similar left and right P2m latencies were observed by ∼21 months of age due to faster maturation rate in the left than right hemisphere. No sex differences in the maturation of the P2m responses were observed. Finally, an earlier left than right hemisphere P2m latency predicted better language performance in older infants (12 to 24 months). Findings indicate the need to consider hemisphere when examining the maturation of auditory cortex neural activity in infants and toddlers and show that the pattern of left-right hemisphere P2m maturation is associated with language performance.

MEG language mapping using a novel automatic ECD algorithm in comparison with MNE, dSPM, and DICS beamformer

Introduction

The single equivalent current dipole (sECD) is the standard clinical procedure for presurgical language mapping in epilepsy using magnetoencephalography (MEG). However, the sECD approach has not been widely used in clinical assessments, mainly because it requires subjective judgements in selecting several critical parameters. To address this limitation, we developed an automatic sECD algorithm (AsECDa) for language mapping.

Methods

The localization accuracy of the AsECDa was evaluated using synthetic MEG data. Subsequently, the reliability and efficiency of AsECDa were compared to three other common source localization methods using MEG data recorded during two sessions of a receptive language task in 21 epilepsy patients. These methods include minimum norm estimation (MNE), dynamic statistical parametric mapping (dSPM), and dynamic imaging of coherent sources (DICS) beamformer.

Results

For the synthetic single dipole MEG data with a typical signal-to-noise ratio, the average localization error of AsECDa was less than 2 mm for simulated superficial and deep dipoles. For the patient data, AsECDa showed better test-retest reliability (TRR) of the language laterality index (LI) than MNE, dSPM, and DICS beamformer. Specifically, the LI calculated with AsECDa revealed excellent TRR between the two MEG sessions across all patients (Cor = 0.80), while the LI for MNE, dSPM, DICS-event-related desynchronization (ERD) in the alpha band, and DICS-ERD in the low beta band ranged lower (Cor = 0.71, 0.64, 0.54, and 0.48, respectively). Furthermore, AsECDa identified 38% of patients with atypical language lateralization (i.e., right lateralization or bilateral), compared to 73%, 68%, 55%, and 50% identified by DICS-ERD in the low beta band, DICS-ERD in the alpha band, MNE, and dSPM, respectively. Compared to other methods, AsECDa's results were more consistent with previous studies that reported atypical language lateralization in 20-30% of epilepsy patients.

Discussion

Our study suggests that AsECDa is a promising approach for presurgical language mapping, and its fully automated nature makes it easy to implement and reliable for clinical evaluations.

Task‐related functional neuroimaging contribution to sex/gender differences in cognition and emotion during development

Recent research has shown that sex/gender (s/g) influences on cognitive functions and related brain anatomy, functional responses, and connectivity are less clear than previously assumed, and most studies investigated adult population. In this mini-review, we summarize research progress in the study of s/g differences in the human brain function as investigated by neuroimaging methods adopting a developmental perspective. In particular, we review original studies published from 2000 to 2021 investigating s/g differences in task-related brain functional activation and connectivity in healthy children and adolescents. We summarize results about studies in the domains of language, visuospatial ability, social cognition, and executive functions. Overall, a clear relation between cognition and brain activation or connectivity pattern is far from being established and the few coherent results should be considered exploratory, despite in some cases, brain function seems to present specific patterns in comparison with what reported in adults. Moreover, future studies should address methodological limitations, such as fragmentation of tasks, lack of control for confounding variables, and lack of longitudinal designs to study developmental trajectories.

Male Predisposition in Cerebellar Mutism Syndrome: a Cohort Study

The aim of this study was to explore the association between sex and cerebellar mutism syndrome and to examine other potential risk factors. This ambispective cohort study examined 218 pediatric patients (132 boys) with a posterior fossa tumor who underwent tumor resection from July 2013 to March 2021. The patients' demographics and tumor characteristics were examined and statistically analyzed to explore the associations among the variables. Multivariable and subgroup analyses were conducted to validate the independent risk factors for cerebellar mutism syndrome (CMS). The male and female patients did not differ significantly in terms of age, tumor size, tumor location, tumor consistency, VP shunt placement before resection, extent of resection, or surgeon, as well as with respect to the presence of hydrocephalus or paraventricular edema. The overall incidence of CMS was 32.6%. The incidence of CMS was significantly higher in male patients than that in female patients (41.7% vs. 18.6%; P = 0.001). In the multivariable analysis, male sex (adjusted odds ratio [OR], 3.27; P = 0.001), solid tumor consistency (adjusted OR, 5.61; P = 0.001), midline location (adjusted OR, 3.78; P = 0.004), and hydrocephalus (adjusted OR, 2.56; P = 0.047) were independent risk factors for the CMS. Chi-square analysis revealed that solid tumor consistency and midline location were associated with medulloblastoma (P < 0.001). Male patients had a higher risk of developing CMS after a posterior fossa tumor resection. Midline location, solid tumor consistency, and hydrocephalus were independent risk factors for CMS.

The beauty of diversity in cognitive neuroscience: The case of sex-related effects in language production networks

Over the past few decades, several studies have focused on potential sex-related differences in the trajectories of language development and functioning. From a behavioral point of view, the available literature shows controversial results: differences between males and females in language production tasks may not always be detectable and, even when they are, are potentially biased by sociological and educational confounding factors. The problem regarding potential sex-related differences in language production has also been investigated at the neural level, again with controversial results. The current minireview focuses on studies assessing sex-related differences in the neural networks of language production. After providing a theoretical framework of language production, it is shown that the few available investigations have provided mixed results. The major reasons for discrepant findings are discussed with theoretical and methodological implications for future studies.

Hand Preference in Adults’ Referential Gestures during Storytelling: Testing for Effects of Bilingualism, Language Ability, Sex and Age

Previous studies have shown that gestures are mediated by the left hemisphere. The primary purpose of this study was to test whether most gestures are also asymmetrical, i.e., produced with the right hand. We also tested four predictors of the degree of right-hand gesture use: bilingualism, language ability, sex, and age. These factors have been related to differences in the degree of language lateralization. English monolinguals, French–English bilinguals, and French monolinguals watched a cartoon and told the story back. For the gestures they produced while speaking, we calculated the percentage produced with the right hand. As predicted, the majority of gestures were right-handed (60%). Bilingualism, language ability, and age were not significantly related to hand choice in either English or French. In English, males tended to produce more right-handed gestures than females. These results raise doubts as to whether hand preference in gestures reflects speech lateralization. We discuss possible alternative explanations for a right-hand preference.

Contributions of electrophysiology for identifying cortical language systems in patients with epilepsy

A crucial element of the surgical treatment of medically refractory epilepsy is to delineate cortical areas that must be spared in order to avoid clinically relevant neurological and neuropsychological deficits postoperatively. For each patient, this typically necessitates determining the language lateralization between hemispheres and language localization within hemisphere. Understanding cortical language systems is complicated by two primary challenges: the extent of the neural tissue involved and the substantial variability across individuals, especially in pathological populations. We review the contributions made through the study of electrophysiological activity to address these challenges. These contributions are based on the techniques of magnetoencephalography (MEG), intracerebral recordings, electrical-cortical stimulation (ECS), and the electrovideo analyses of seizures and their semiology. We highlight why no single modality alone is adequate to identify cortical language systems and suggest avenues for improving current practice.

Sex Differences in White Matter Pathways Related to Language Ability

Evidence from functional imaging studies points to a role for gender in language ability. However, recent studies suggest that sex differences in the neural basis of language are still unclear, reflecting a complex interaction between sex and language ability. We used diffusion weighted magnetic resonance imaging and global probabilistic tractography to investigate white matter (WM) pathways between 32 male and 35 age- and IQ-matched female adult participants in relation to their verbal abilities. Males showed higher fractional anisotropy (FA) in the left anterior thalamic radiations (ATR), right cingulum-angular bundle, right corticospinal tract, bilateral superior longitudinal fasciculus-temporal terminations, bilateral uncinate fasciculus (UNC), and corpus callosum-forceps minor when compared with the female group. In contrast, females showed higher radial diffusivity (RD) in the left ATR and left UNC when compared to the male group. The relationship between WM metrics and verbal ability also differed across the two groups: a negative correlation between verbal comprehension index (VCI) and FA as well as axial diffusivity (AD) in left cingulum-cingulate gyrus (CCG) supracallosal bundle in males but not in females; a negative correlation between verbal IQ (VIQ) and FA in the right corticospinal tract (CST), and a positive correlation between VCI and RD in corpus callosum-forceps minor in the female but not in the male group. A direct comparison of these correlation coefficients yielded significant differences between the groups for the VCI-AD and VIQ -FA associations. The findings may reflect sex differences in WM related to language ability.

Sex differences in early communication development: behavioral and neurobiological indicators of more vulnerable communication system development in boys

Perhaps due to different roles they have had in social groups during evolution, men and women differ in their verbal abilities. These differences are also (if not even more) present in children, both in the course of typical and pathological development. Beside the fact that girls have a well-documented advantage in early language development, almost all developmental disorders primarily affecting communication, speech, and language skills are more frequent in boys. The sex-related difference in the prevalence of these disorders is especially pronounced in autism spectrum disorder (1 girl for each 4-5 boys is affected). The aim of this review is to present the sex differences in typical communication and language development and in the prevalence of communication-related neurodevelopmental disorders. Also, a special focus is put on data from the field of neuroscience that might provide insight into the neurobiological mechanisms that can add to the understanding of this phenomenon. We argue that the functional organization of the female brain gives women an inherent advantage in the acquisition of communication and language system over men.

Sex differences in early communication development: behavioral and neurobiological indicators of more vulnerable communication system development in boys

Perhaps due to different roles they have had in social groups during evolution, men and women differ in their verbal abilities. These differences are also (if not even more) present in children, both in the course of typical and pathological development. Beside the fact that girls have a well-documented advantage in early language development, almost all developmental disorders primarily affecting communication, speech, and language skills are more frequent in boys. The sex-related difference in the prevalence of these disorders is especially pronounced in autism spectrum disorder (1 girl for each 4-5 boys is affected). The aim of this review is to present the sex differences in typical communication and language development and in the prevalence of communication-related neurodevelopmental disorders. Also, a special focus is put on data from the field of neuroscience that might provide insight into the neurobiological mechanisms that can add to the understanding of this phenomenon. We argue that the functional organization of the female brain gives women an inherent advantage in the acquisition of communication and language system over men.

Machine learning for MEG during speech tasks

We consider whether a deep neural network trained with raw MEG data can be used to predict the age of children performing a verb-generation task, a monosyllable speech-elicitation task, and a multi-syllabic speech-elicitation task. Furthermore, we argue that the network makes predictions on the grounds of differences in speech development. Previous work has explored taking 'deep' neural networks (DNNs) designed for, or trained with, images to classify encephalographic recordings with some success, but this does little to acknowledge the structure of these data. Simple neural networks have been used extensively to classify data expressed as features, but require extensive feature engineering and pre-processing. We present novel DNNs trained using raw magnetoencephalography (MEG) and electroencephalography (EEG) recordings that mimic the feature-engineering pipeline. We highlight criteria the networks use, including relative weighting of channels and preferred spectro-temporal characteristics of re-weighted channels. Our data feature 92 subjects aged 4-18, recorded using a 151-channel MEG system. Our proposed model scores over 95% mean cross-validation accuracy distinguishing above and below 10 years of age in single trials of un-seen subjects, and can classify publicly available EEG with state-of-the-art accuracy.

Tracing the structural origins of atypical language representation: consequences of prenatal mirror-imaged brain asymmetries in a dizygotic twin couple

We investigated the predictive value of prenatal superior temporal sulcus (STS) depth asymmetry in a special case of a female dizygotic twin that showed inverted prenatal asymmetry of this structure. For this purpose, we performed a follow-up investigation in this former fetus at the age of seven, where we assessed the functional language lateralization using task-based and resting-state functional magnetic resonance imaging (fMRI). As control group we employed her twin brother, who showed a typical folding pattern prenatally, as well as a complementary set of four age-matched children that had fetal MRI of their brains and typical STS depth asymmetry. We could show that the twin with the atypical fetal asymmetry of the STS also showed significantly differing rightward language lateralization in the frontal and temporal lobes. Additionally, resting-state data suggest a stronger connectivity between inferior frontal gyri in this case. The twin showed normal cognitive development. This result gives a first glimpse into the STS' atypical asymmetry being a very early morphological marker for later language lateralization.

A systematic literature review of sex differences in childhood language and brain development

The extent of sex differences in childhood language development is unclear. We conducted a systematic literature review synthesizing results from studies examining sex differences in brain structure and function relevant to language development during childhood. We searched PubMed and Scopus databases, and this returned a total of 46 published studies meeting criteria for inclusion that directly examined sex differences in brain development relevant to language function in children. The results indicate that: (a) sex differences in brain structure or function do not necessarily lead to differences in language task performance; (b) evidence for sex differences in brain and language development are limited; (c) when present, sex differences often interact with a variety of factors such as age and task. Overall, the magnitude of sexual dimorphism of brain developmental trajectories associated with language is not as significant as previously thought. Sex differences were found, however, in studies employing tighter age ranges. This suggests that sex differences may be more prominent during certain developmental stages but are negligible in other stages, likely due to different rates of maturation between the sexes. More research is needed to improve our understanding of how sex differences may arise due to the influence of sex hormones and developmental stages, and how these differences may lead to differences in various language task performance. These studies are expected to provide normative information that may be used in studies examining neurodevelopmental disorders that frequently affect more males than females, and also often affect language development.

fMRI connectivity of expressive language in young children and adolescents

Studies of language representation in development have shown a bilateral distributed pattern of activation that becomes increasingly left-lateralized and focal from young childhood to adulthood. However, the level by which canonical and extra-canonical regions, including subcortical and cerebellar regions, contribute to language during development has not been well-characterized. In this study, we employed fMRI connectivity analyses (fcMRI) to characterize the distributed network supporting expressive language in a group of young children (age 4-6) and adolescents (age 16-18). We conducted an fcMRI analysis using seed-to-voxel and seed-to-ROI (region of interest) strategies to investigate interactions of left pars triangularis with other brain areas. The analyses showed significant interhemispheric connectivity in young children, with a minimal connectivity of the left pars triangularis to subcortical and cerebellar regions. In contrast, adolescents showed significant connectivity between the left IFG seed and left perisylvian cortex, left caudate and putamen, and regions of the right cerebellum. Importantly, fcMRI analyses indicated significant differences between groups at 3 anatomical clusters, including left IFG, left supramarginal gyrus, and right cerebellar crura, suggesting a role in the functional development of language.

Alcoholism and sexual dimorphism in the middle longitudinal fascicle: a pilot study

Alcoholism can lead to a complex mixture of cognitive and emotional deficits associated with abnormalities in fronto-cortico-striatal-limbic brain circuitries. Given the broad variety of neurobehavioral symptoms, one would also expect alterations of postrolandic neocortical systems. Thus, we used diffusion tensor imaging (DTI) to study the integrity of the middle longitudinal fascicle (MdLF), a major postrolandic association white matter tract that extends from the superior temporal gyrus to the parietal and occipital lobes, in individuals with a history of chronic alcohol abuse. DTI data were acquired on a 3 Tesla scanner in 30 abstinent alcoholics (AL; 9 men) and 25 nonalcoholic controls (NC; 8 men). The MdLF was determined using DTI-based tractography. Volume of the tract, fractional anisotropy (FA), radial (RD), and axial (AD) diffusivity, were compared between AL and NC, with sex and hemispheric laterality as independent variables. The association of DTI measures with neuropsychological performance was evaluated. Men showed bilateral reduction of MdLF volume and abnormal diffusion measurements of the left MdLF. Analyses also indicated that the left MdLF diffusion measurements in AL men were negatively associated with Verbal IQ and verbal fluency test scores. Abstinent alcoholic men display macrostructural abnormalities in the MdLF bilaterally, indicating an overall white matter deficit. Additionally, microstructural deficits of the left MdLF suggest more specific alterations associated with verbal skills in men.

Sex differences in lateralization of semantic verbal fluency in temporal lobe epilepsy

When differences exist, women tend to outperform men on measures of verbal fluency, possibly due to greater bilateral language representation. Patients with temporal lobe epilepsy (TLE) have a higher rate of atypical cortical language representation than the general population, making them a population of interest for the study of language. For the current study, 78 TLE patients (51% male, 51% left temporal focus) underwent pre-surgical neuropsychological evaluations. Retrospective data analyses investigated the impact of seizure laterality and sex on letter and semantic verbal fluency. Results indicated an interaction between sex and laterality for semantic, but not letter, verbal fluency. Males with left TLE exhibited significantly worse semantic fluency than males with right TLE, whereas females' semantic fluency did not differ by seizure focus. These data indicate that females with TLE may indeed engage in more bilateral hemispheric processing of semantic verbal fluency, whereas males may be more reliant on left temporal cortical function for this task.