Contribution of the Cerebellum and the Basal Ganglia to Language Production: Speech, Word Fluency, and Sentence Construction-Evidence from Pathology

Exploring the utility of process scores in elucidating the role of cognitive and affective factors that influence verbal fluency performance in Parkinson's disease

OBJECTIVES

Cognitive and affective factors have been implicated in verbal fluency (VF) performance in Parkinson's disease (PD). This exploratory study aimed to investigate the relationships between cognitive and affective variables on traditional ("core") and "process" (error and interval) scores of VF and elucidate unique information these scores may provide regarding mechanisms underlying VF.

METHODS

Sixty-two PD patients without dementia completed clinical neuropsychological examinations consisting of attention, processing speed, language, executive functioning, visuospatial, memory, and mood measures. Hierarchical regression and negative binomial regression analyses were used to evaluate relationships between outcome and predictor variables.

RESULTS

Generativity results revealed that processing speed and working memory explained up to 34% of the variance of total letter fluency responses (p = <.001) and processing speed explained 24% of the variance for total semantic fluency (p = .003). For category switching generativity, only age predicted 20% of the variance (p = .01). Two executive functioning measures were negatively associated with error production over the duration (b = -.055, p = .028; b = -.062, p = .004) and final 45-second interval (b = -.072, p = .003; b = -.044, p = .033) of the category switching task. In the initial 15-second task interval, a positive predictive relationship between error production and indifference apathy (b = .616, p = .044) was demonstrated.

CONCLUSIONS

Findings demonstrate the potential utility of "process" scores in detecting subtle cognitive impairment in Parkinson's disease patients without dementia and tentatively evidence the role of indifference apathy in task initiation.

Clinical characteristics of post-stroke basal ganglia aphasia and the study of language-related white matter tracts based on diffusion spectrum imaging

BACKGROUND

Stroke often damages the basal ganglia, leading to atypical and transient aphasia, indicating that post-stroke basal ganglia aphasia (PSBGA) may be related to different anatomical structural damage and functional remodeling rehabilitation mechanisms. The basal ganglia contain dense white matter tracts (WMTs). Hence, damage to the functional tract may be an essential anatomical structural basis for the development of PSBGA.

METHODS

We first analyzed the clinical characteristics of PSBGA in 28 patients and 15 healthy controls (HCs) using the Western Aphasia Battery and neuropsychological test batteries. Moreover, we investigated white matter injury during the acute stage using diffusion magnetic resonance imaging scans for differential tractography. Finally, we used multiple regression models in correlation tractography to analyze the relationship between various language functions and quantitative anisotropy (QA) of WMTs.

RESULTS

Compared with HCs, patients with PSBGA showed lower scores for fluency, comprehension (auditory word recognition and sequential commands), naming (object naming and word fluency), reading comprehension of sentences, Mini-Mental State Examination, and Montreal Cognitive Assessment, along with increased scores in Hamilton Anxiety Scale-17 and Hamilton Depression Scale-17 within 7 days after stroke onset (P < 0.05). Differential tractography revealed that patients with PSBGA had damaged fibers, including in the body fibers of the corpus callosum, left cingulum bundles, left parietal aslant tracts, bilateral superior longitudinal fasciculus II, bilateral thalamic radiation tracts, left fornix, corpus callosum tapetum, and forceps major, compared with HCs (FDR < 0.02). Correlation tractography highlighted that better comprehension was correlated with a higher QA of the left inferior fronto-occipital fasciculus (IFOF), corpus callosum forceps minor, and left extreme capsule (FDR < 0.0083). Naming was positively associated with the QA of the left IFOF, forceps minor, left arcuate fasciculus, and uncinate fasciculus (UF) (FDR < 0.0083). Word fluency of naming was also positively associated with the QA of the forceps minor, left IFOF, and thalamic radiation tracts (FDR < 0.0083). Furthermore, reading was positively correlated with the QA of the forceps minor, left IFOF, and UF (FDR < 0.0083).

CONCLUSION

PSBGA is primarily characterized by significantly impaired word fluency of naming and preserved repetition abilities, as well as emotional and cognitive dysfunction. Damaged limbic pathways, dorsally located tracts in the left hemisphere, and left basal ganglia pathways are involved in PSBGA pathogenesis. The results of connectometry analysis further refine the current functional localization model of higher-order neural networks associated with language functions.

The volume and structural covariance network of thalamic nuclei in patients with Wilson's disease: an investigation of the association with neurological impairment

OBJECTIVE

This study aimed to examine the volumes of thalamic nuclei and the intrinsic thalamic network in patients with Wilson's disease (WDs), and to explore the correlation between these volumes and the severity of neurological symptoms.

METHODS

A total of 61 WDs and 33 healthy controls (HCs) were included in the study. The volumes of 25 bilateral thalamic nuclei were measured using structural imaging analysis with Freesurfer, and the intrinsic thalamic network was evaluated through structural covariance network (SCN) analysis.

RESULTS

The results indicated that multiple thalamic nuclei were smaller in WDs compared to HCs, including mediodorsal medial magnocellular (MDm), anterior ventral (AV), central median (CeM), centromedian (CM), lateral geniculate (LGN), limitans-suprageniculate (L-Sg), reuniens-medial ventral (MV), paracentral (Pc), parafascicular (Pf), paratenial (Pt), pulvinar anterior (PuA), pulvinar inferior (PuI), pulvinar medial (PuM), ventral anterior (VA), ventral anterior magnocellular (VAmc), ventral lateral anterior (VLa), ventral lateral posterior (VLp), ventromedial (VM), ventral posterolateral (VPL), and right middle dorsal intralaminar (MDI). The study also found a negative correlation between the UWDRS scores and the volume of the right MDm. The intrinsic thalamic network analysis showed abnormal topological properties in WDs, including increased mean local efficiency, modularity, normalized clustering coefficient, small-world index, and characteristic path length, and a corresponding decrease in mean node betweenness centrality. WDs with cerebral involvement had a lower modularity compared to HCs.

CONCLUSIONS

The findings suggest that the majority of thalamic nuclei in WDs exhibit significant volume reduction, and the atrophy of the right MDm is closely related to the severity of neurological symptoms. The intrinsic thalamic network in WDs demonstrated abnormal topological properties, indicating a close relationship with neurological impairment.

Proceedings of the first global meeting of the Posterior Fossa Society: state of the art in cerebellar mutism syndrome

PURPOSE

The Posterior Fossa Society, an international multidisciplinary group, hosted its first global meeting designed to share the current state of the evidence across the multidisciplinary elements of pediatric post-operative cerebellar mutism syndrome (pCMS). The agenda included keynote talks from world-leading speakers, compelling abstract presentations and engaging discussions led by members of the PFS special interest groups.

METHODS

This paper is a synopsis of the first global meeting, a 3-day program held in Liverpool, England, UK, in September 2022.

RESULTS

Topics included nosology, patient and family experience, cerebellar modulation of cognition, and cerebellar cognitive affective syndrome. In addition, updates from large-scale studies were shared as well as abstracts across neuroradiology, neurosurgery, diagnosis/scoring, ataxia, and rehabilitation.

CONCLUSIONS

Based on data-driven evidence and discussions, each special interest group created research priorities to target before the second global meeting, in the spring of 2024.

Neurodevelopmental trajectories of cerebellar grey matter associated with verbal abilities in males with autism spectrum disorder

Autism spectrum disorder (ASD) is a neurodevelopmental condition frequently associated with structural cerebellar abnormalities. Whether cerebellar grey matter volumes (GMV) are linked to verbal impairments remains controversial. Here, the association between cerebellar GMV and verbal abilities in ASD was examined across the lifespan. Lobular segmentation of the cerebellum was performed on structural MRI scans from the ABIDE I dataset in male individuals with ASD (N=144, age: 8.5-64.0 years) and neurotypical controls (N=188; age: 8.0-56.2 years). Stepwise linear mixed effects modeling including group (ASD vs. neurotypical controls), lobule-wise GMV, and age was performed to identify cerebellar lobules which best predicted verbal abilities as measured by verbal IQ (VIQ). An age-specific association between VIQ and GMV of bilateral Crus II was found in ASD relative to neurotypical controls. In children with ASD, higher VIQ was associated with larger GMV of left Crus II but smaller GMV of right Crus II. By contrast, in adults with ASD, higher VIQ was associated with smaller GMV of left Crus II and larger GMV of right Crus II. These findings indicate that relative to the contralateral hemisphere, an initial reliance on the language-nonspecific left cerebellar hemisphere is offset by more typical right-lateralization in adulthood.

The role of cerebellum in learned vocal communication in adult songbirds

Injury, tumors, ischemia, and lesions in the cerebellum show the involvement of this region in human speech. The association of the cerebellum with learned birdsong has only been identified recently. Cerebellar dysfunction in young songbirds causes learning disabilities, but its role in adult songbirds has not been established. The aim of this study was to investigate the role of the deep cerebellar nuclei (DCN) in adult birdsong. We created bilateral excitotoxic lesions in the DCN of adult male zebra finches (Taeniopygia guttata) and recorded their songs for up to 4 months. Using magnetic resonance imaging (MRI) and immunohistochemistry, we validated the lesion efficacy. We found that the song duration significantly increased from 14 weeks post-op; the increase in duration was caused by a greater number of introductory notes as well as a greater number of syllables sung after the introductory notes. On the other hand, the motif duration decreased from 8 weeks after DCN lesions were induced, which was due to faster singing of syllables, not changes in inter-syllable interval length. DCN lesions also caused a decrease in the fundamental frequency of syllables. In summary, we showed that DCN lesions influence the temporal and acoustic features of birdsong. These results suggest that the cerebellum influences singing in adult songbirds.

Dynamics of striatal action selection and reinforcement learning

Spiny projection neurons (SPNs) in dorsal striatum are often proposed as a locus of reinforcement learning in the basal ganglia. Here, we identify and resolve a fundamental inconsistency between striatal reinforcement learning models and known SPN synaptic plasticity rules. Direct-pathway (dSPN) and indirect-pathway (iSPN) neurons, which promote and suppress actions, respectively, exhibit synaptic plasticity that reinforces activity associated with elevated or suppressed dopamine release. We show that iSPN plasticity prevents successful learning, as it reinforces activity patterns associated with negative outcomes. However, this pathological behavior is reversed if functionally opponent dSPNs and iSPNs, which promote and suppress the current behavior, are simultaneously activated by efferent input following action selection. This prediction is supported by striatal recordings and contrasts with prior models of SPN representations. In our model, learning and action selection signals can be multiplexed without interference, enabling learning algorithms beyond those of standard temporal difference models.

Diffusion tensor imaging-based multi-fiber tracking reconstructions can regionally differentiate phonetic versus prosodic subtypes of progressive apraxia of speech

Two subtypes of progressive apraxia of speech (PAOS) have been recognized: phonetic PAOS (PAOS_ph) where speech output is dominated by distorted sound substitutions and prosodic PAOS (PAOS_pr) which is dominated by segmented speech. We investigate whether these PAOS subtypes have different white matter microstructural abnormalities measured by diffusion tensor tractography. Thirty-three patients with PAOS (21 PAOS_ph and 12 PAOS_pr) and 19 healthy controls were recruited by the Neurodegenerative Research Group (NRG) and underwent diffusion MRI. Using a whole-brain tractography approach, fractional anisotropy (FA) and mean diffusivity (MD) were extracted for cortico-cortical, cortico-subcortical, cortical-projection, and cerebello-cortical white matter tracts. A hierarchical linear model was applied to assess tract-level FA and MD across groups. Both PAOS_ph and PAOS_pr showed degeneration of cortico-cortical, cortico-subcortical, cortical-projection, and cerebello-cortical white matter tracts compared to controls. However, degeneration of the body of corpus callosum, superior thalamic radiation, and superior cerebellar peduncle was greater in PAOS_pr compared to PAOS_ph, and degeneration of the inferior segment of the superior longitudinal fasciculus (SLF) was greater in PAOS_ph compared to PAOS_pr. Worse parkinsonism correlated with greater degeneration of cortico-cortical and cortico-subcortical tracts in PAOS_ph. Apraxia of speech articulatory error score correlated with degeneration of the superior cerebellar peduncle tracts in PAOS_pr. Phonetic and prosodic PAOS involve the compromise of a similar network of tracts, although there are connectivity differences between types. Whereas clinical parameters are the current gold standard to distinguish PAOS subtypes, our results allege the use of DTI-based tractography as a supplementary method to investigate such variants.

Cerebellar-Induced Aphasia After Stroke: Evidence for the "Linguistic Cerebellum"

The cerebellum is traditionally known to subserve motor functions. However, for several decades, the concept of the "cerebellar cognitive affective syndrome" has evolved. Studies in healthy participants and patients have confirmed the cerebellar role in language. The exact involvement of the cerebellum regarding cerebellar aphasia remains uncertain. We included 43 cerebellar stroke patients who were tested at 3 months post-onset with the Boston Naming Test (BNT), the Token Test (TT), and the Diagnostic Instrument for Mild Aphasia (DIMA). Lesion side (left/right) and volume (cm3) were investigated. Patients significantly deviated on the following: BNT (p<0.001), TT (p<0.05), DIMA subtests: sentences repetition (p=0.001), semantic odd-picture-out (p<0.05), sentence completion (p<0.05) without an effect of lesion location (left/right) or volume (cm3) (p>0.05). Our clinical study confirms a non-lateralized cerebellar aphasia post-stroke, characterized by impairments in word retrieval, phonology, semantics, and syntax resembling cerebral-induced aphasia. The integral cerebellum appears to interact with eloquent cortico-subcortical language areas.

The Impact of Demographic and Clinical Factors on the Quality of Life in Patients with Neurodegenerative Cerebellar Ataxias

In neurodegenerative cerebellar ataxias, not only ataxia but also extra-cerebellar signs have a significant impact on patients' health related to quality of life (HRQoL). The aim of this study was to evaluate the various aspects of HRQoL and predictors of QoL in patients with neurodegenerative cerebellar ataxias. We included a total of 107 patients with cerebellar degenerative ataxia. Patients filled out the validated Serbian version of the SF-36 used for the assessment of HRQoL. All patients were clinically evaluated using SARA, INAS, and neuropsychological tests to assess their global cognitive status and different psychiatric scales. The most frequent types of neurodegenerative cerebellar ataxias were autosomal dominant ataxias (38.3%) and sporadic ataxias (32.7%). Mean age at diagnosis was 35.3 ± 16.23 years, and disease duration was on average 12.1 ± 9.91 years. Mean total SF-36 score was 50.63 ± 20.50. Hierarchical regression analysis showed that in the case of the PHC score, the most significant predictors are the patient's actual age, severity of ataxia, and ACE total score. For MHC, the Hamilton depression score was the most important predictor. Our study has shown that HRQoL measured by SF-36 in patients with neurodegenerative cerebellar disorders is strongly influenced by impaired mobility and depression.

Systematic Review and Meta-analysis of Language Symptoms due to Cerebellar Injury

To date, cerebellar contribution to language is well established via clinical and neuroimaging studies. However, the particular functional role of the cerebellum in language remains to be clarified. In this study, we present the first systematic review of the diverse language symptoms in spoken language after cerebellar lesion that were reported in case studies for the last 30 years (18 clinical cases from 13 papers), and meta-analysis using cluster analysis with bootstrap and symptom co-occurrence analysis. Seven clusters of patients with similar language symptoms after cerebellar lesions were found. Co-occurrence analysis revealed pairs of symptoms that tend to be comorbid. Our results imply that the "linguistic cerebellum" has a multiform contribution to language function. The most possible mechanism of such contribution is the cerebellar reciprocal connectivity with supratentorial brain regions, where the cerebellar level of the language network has a general modulation function and the supratentorial level is more functionally specified. Based on cerebellar connectivity with supratentorial components of the language network, the "linguistic cerebellum" might be further functionally segregated.

Neurobiological and pathophysiological concepts of Christfried Jakob (1866-1956) on language and aphasia: An English translation of two communications [1910,1932] and a modern perspective

The aim of the present article is to preserve, in English translation, two historical communications on aphasia and the pathophysiology of language by the neurobiologist Christfried Jakob (1866-1956) of Buenos Aires, and to place them in a modern perspective. The morphofunctional basis of human language and its pathology occupied Jakob's mind over three decades. His synthetic conclusions were based on the neuropathological examination of dozens of aphasic cases from the Hospital de Las Mercedes and the National Women's Psychiatric Hospital between 1906 and 1936. Special mention is made of the role of the cerebellum, the thalamus, and their connections with the cerebral cortex, and the language network. Current research and imaging studies support and elaborate that which Jacob presented so many years ago; many of his analyses and ideas are informative and remain relevant today.

Association of cerebellar volume with cognitive and motor function in adults with congenital heart disease

INTRODUCTION

Patients with congenital heart disease (CHD) are at risk for cognitive and motor function impairments, brain injury, and smaller total brain volumes. The specific vulnerability of the cerebellum and its role in cognitive and motor functions in adults with congenital heart disease is not well defined.

METHODS

Forty-three patients with CHD and 53 controls between 18 and 32 years underwent brain magnetic resonance imaging and cognitive, executive (EF), and motor function assessment. Cerebellar volumes were obtained using EasyMeasure and SUIT Toolbox. Associations between cerebellar volumes and cognitive and motor function were calculated using linear models.

RESULTS

General cognitive and pure motor functions were lower in patients compared to controls (P < 0.05). Executive functions were within the normal range. While total cerebellar volumes and the anterior lobes were similar in patients and controls (P > 0.1), the posterior cerebellar lobe was smaller in patients with more complex CHD (P = 0.006). Smaller posterior cerebellar gray matter was not associated with cognitive functions. Smaller anterior cerebellar gray matter was not significantly related to motor functions (P > 0.1).

CONCLUSION

In adults with CHD, cerebellar volume was largely unimpaired. Patients with more complex CHD may be vulnerable to changes in the posterior cerebellar gray matter. We found no significant contribution of cerebellar gray matter to cognitive and motor impairments. More advanced imaging techniques are necessary to clarify the contribution of the cerebellum to cognitive and motor functions.

Ferdinando Rossi Lecture: the Cerebellar Cognitive Affective Syndrome-Implications and Future Directions

The notion that the cerebellum is devoted exclusively to motor control has been replaced by a more sophisticated understanding of its role in neurological function, one that includes cognition and emotion. Early clinical reports, as well as physiological and behavioral studies in animal models, raised the possibility of a nonmotor role for the cerebellum. Anatomical studies demonstrate cerebellar connectivity with the distributed neural circuits linked with autonomic, sensorimotor, vestibular, associative and limbic/paralimbic brain areas. Identification of the cerebellar cognitive affective syndrome in adults and children underscored the clinical relevance of the role of the cerebellum in cognition and emotion. It opened new avenues of investigation into higher order deficits that accompany the ataxias and other cerebellar diseases, as well as the contribution of cerebellar dysfunction to neuropsychiatric and neurocognitive disorders. Brain imaging studies demonstrate the complexity of cerebellar functional topography, revealing a double representation of the sensorimotor cerebellum in the anterior lobe and lobule VIII and a triple cognitive representation in the cerebellar posterior lobe, as well as representation in the cerebellum of the intrinsic connectivity networks identified in the cerebral hemispheres. This paradigm shift in thinking about the cerebellum has been advanced by the theories of dysmetria of thought and the universal cerebellar transform, harmonizing the dual anatomic realities of homogeneously repeating cerebellar cortical microcircuitry set against the heterogeneous and topographically arranged cerebellar connections with extracerebellar structures. This new appreciation of the cerebellar incorporation into circuits that subserve cognition and emotion enables deeper understanding and improved care of our patients with cerebellar ataxias and novel cerebellar-based approaches to therapy in neuropsychiatry.

Analyses of correct responses and errors on measures of verbal fluency among Parkinson's disease and essential tremor patients

Objective: Parkinson's disease (PD) and essential tremor (ET) involve neuroanatomical circuitry that impact frontal lobe functioning, via the striatum and cerebellum, respectively. The aim of this exploratory study was to investigate quantitative and qualitative performance between and within these groups on measures of verbal fluency. Method: Sixty-three PD and 53 ET patients completed neuropsychological testing. Linear regression models with robust variance estimation compared verbal fluency performance between groups related to correct responses and errors. Paired t-tests investigated within group error rates. Results: PD patients gave more correct responses for phonological (β ̂   =5.3, p=.01) and category fluency (β ̂   =4.1, p=.01) than ET patients; however, when processing speed was added as a covariate, this attenuated performance on both measures and only phonological fluency remained significant (β ̂   =4.0, p=.04). There were no statistical differences in error scores between groups. Error rates within groups suggested that PD patients had higher error rates in total errors and perseveration errors on phonological fluency (M = 2.6, p=.00; M = 1.6, p=.00) and higher total errors and set-loss error rates on category switching (M = 5.1, p<.001; M = 4.1, p<.001). ET patients had higher error rate with relation to total errors and set-loss errors on phonological fluency (M = 2.5, p=.00; M = 1.5, p=.02) and category switching (M = 3.9, p=,00; M = 3.9, p<.001). Conclusions: PD patients performed better than ET patients on phonological fluency. PD patients appear to make more perseveration errors on phonological fluency, while ET patients made more set-loss errors. Implications for frontal lobe dysfunction and clinical impact are discussed.

Computational analysis on verbal fluency reveals heterogeneity in subjective language interests and brain structure

Language is an essential higher cognitive function in humans and is often affected by psychiatric and neurological disorders. Objective measures like the verbal fluency test are often used to determine language dysfunction. Recent applications of computational approaches broaden insights into language-related functions. In addition, individuals diagnosed with a psychiatric or neurological disorder also often report subjective difficulties in language-related functions. Therefore, we investigated the association between objective and subjective measures of language functioning, on the one hand, and inter-individual structural variations in language-related brain areas, on the other hand. We performed a Latent Semantic analysis (LSA) on a semantic verbal fluency task in 101 healthy adult participants. To investigate if these objective measures are associated with a subjective one, we examined assessed subjective natural tendency of interest in language-related activity with a study-specific questionnaire. Lastly, a voxel-based brain morphometry (VBM) was conducted to reveal associations between objective (LSA) measures and structural changes in language-related brain areas. We found a positive correlation between the LSA measure cosine similarity and the subjective interest in language. Furthermore, we found that higher cosine similarity corresponds to higher gray matter volume in the right cerebellum. The results suggest that people with higher interests in language access semantic knowledge in a more organized way exhibited by higher cosine similarity and have larger grey matter volume in the right cerebellum, when compared to people with lower interests. In conclusion, we demonstrate that there is inter-individual diverseness of accessing the semantic knowledge space and that it is associated with subjective language interests as well as structural differences in the right cerebellum.

Cerebro-cerebellar networks facilitate learning through feedback decoupling

Behavioural feedback is critical for learning in the cerebral cortex. However, such feedback is often not readily available. How the cerebral cortex learns efficiently despite the sparse nature of feedback remains unclear. Inspired by recent deep learning algorithms, we introduce a systems-level computational model of cerebro-cerebellar interactions. In this model a cerebral recurrent network receives feedback predictions from a cerebellar network, thereby decoupling learning in cerebral networks from future feedback. When trained in a simple sensorimotor task the model shows faster learning and reduced dysmetria-like behaviours, in line with the widely observed functional impact of the cerebellum. Next, we demonstrate that these results generalise to more complex motor and cognitive tasks. Finally, the model makes several experimentally testable predictions regarding cerebro-cerebellar task-specific representations over learning, task-specific benefits of cerebellar predictions and the differential impact of cerebellar and inferior olive lesions. Overall, our work offers a theoretical framework of cerebro-cerebellar networks as feedback decoupling machines.

Disembodiment and Language in Schizophrenia: An Integrated Psychopathological and Evolutionary Perspective

Different hypotheses have flourished to explain the evolutionary paradox of schizophrenia. In this contribution, we sought to illustrate how, in the schizophrenia spectrum, the concept of embodiment may underpin the phylogenetic and developmental pathways linking sensorimotor processes, the origin of human language, and the construction of a basic sense of the self. In particular, according to an embodied model of language, we suggest that the reuse of basic sensorimotor loops for language, while enabling the development of fully symbolic thought, has pushed the human brain close to the threshold of a severe disruption of self-embodiment processes, which are at the core of schizophrenia psychopathology. We adopted an inter-disciplinary approach (psychopathology, neuroscience, developmental biology) within an evolutionary framework, to gain an integrated, multi-perspectival model on the origin of schizophrenia vulnerability. A maladaptive over-expression of evolutionary-developmental trajectories toward language at the expense of embodiment processes would have led to the evolutionary "trade-off" of a hyper-symbolic activity to the detriment of a disembodied self. Therefore, schizophrenia psychopathology might be the cost of long-term co-evolutive interactions between brain and language.

Delving into the Genetic Causes of Language Impairment in a Case of Partial Deletion of NRXN1

Introduction

Copy-number variations (CNVs) impacting on small DNA stretches and associated with language deficits provide a unique window to the role played by specific genes in language function.

Methods

We report in detail on the cognitive, language, and genetic features of a girl bearing a small deletion (0.186 Mb) in the 2p16.3 region, arr[hg19] 2p16.3(50761778_50947729)×1, affecting exons 3-7 of NRXN1, a neurexin-coding gene previously related to schizophrenia, autism (ASD), attention deficit hyperactivity disorder (ADHD), mood disorder, and intellectual disability (ID).

Results

The proband exhibits many of the features commonly found in subjects with deletions of NRXN1, like ASD-like traits (including ritualized behaviors, disordered sensory aspects, social disturbances, and impaired theory of mind), ADHD symptoms, moderate ID, and impaired speech and language. Regarding this latter aspect, we observed altered speech production, underdeveloped phonological awareness, minimal syntax, serious shortage of active vocabulary, impaired receptive language, and inappropriate pragmatic behavior (including lack of metapragmatic awareness and communicative use of gaze). Microarray analyses point to the dysregulation of several genes important for language function in the girl compared to her healthy parents.

Discussion

Although some basic cognitive deficit - such as the impairment of executive function - might contribute to the language problems exhibited by the proband, molecular evidence suggests that they might result, to a great extent, from the abnormal expression of genes directly related to language.

Association of Developmental Language Disorder With Comorbid Developmental Conditions Using Algorithmic Phenotyping

IMPORTANCE

Developmental language disorder (DLD) is a common (with up to 7% prevalence) yet underdiagnosed childhood disorder whose underlying biological profile and comorbidities are not fully understood, especially at the population level.

OBJECTIVE

To identify clinically relevant conditions that co-occur with DLD at the population level.

DESIGN, SETTING, AND PARTICIPANTS

This case-control study used an electronic health record (EHR)-based population-level approach to compare the prevalence of comorbid health phenotypes between DLD cases and matched controls. These cases were identified using the Automated Phenotyping Tool for Identifying Developmental Language Disorder algorithm of the Vanderbilt University Medical Center EHR, and a phenome enrichment analysis was used to identify comorbidities. An independent sample was selected from the Geisinger Health System EHR to test the replication of the phenome enrichment using the same phenotyping and analysis pipeline. Data from the Vanderbilt EHR were accessed between March 2019 and October 2020, while data from the Geisinger EHR were accessed between January and March 2022.

MAIN OUTCOMES AND MEASURES

Common and rare comorbidities of DLD at the population level were identified using EHRs and a phecode-based enrichment analysis.

RESULTS

Comorbidity analysis was conducted for 5273 DLD cases (mean [SD] age, 16.8 [7.2] years; 3748 males [71.1%]) and 26 353 matched controls (mean [SD] age, 14.6 [5.5] years; 18 729 males [71.1%]). Relevant phenotypes associated with DLD were found, including learning disorder, delayed milestones, disorders of the acoustic nerve, conduct disorders, attention-deficit/hyperactivity disorder, lack of coordination, and other motor deficits. Several other health phenotypes not previously associated with DLD were identified, such as dermatitis, conjunctivitis, and weight and nutrition, representing a new window into the clinical complexity of DLD.

CONCLUSIONS AND RELEVANCE

This study found both rare and common comorbidities of DLD. Comorbidity profiles may be leveraged to identify risk of additional health challenges, beyond language impairment, among children with DLD.

1H-magnetic resonance spectroscopy and its role in predicting neurodevelopmental impairment in preterm neonates: A systematic review

To assess the diagnostic utility of proton (1H) magnetic resonance spectroscopy in early diagnosis of neurodevelopmental impairment in preterm newborns. Systematic review performed in compliance with the PRISMA statements. Eligible articles were searched in MEDLINE, Scopus, and ISI Web of Science databases using the following medical subject headings and terms: "magnetic resonance spectroscopy," "infant," and "newborn." Studies of any design published until 20 December 2021 and fulfilling the following criteria were selected: (1) studies including newborns with gestational age at birth <37 weeks which underwent at least one 1H-MRS scan within 52 weeks' postmenstrual age and neurodevelopmental assessment within 4 years of age; (2) studies in which preterm newborns with congenital infections, genetic disorders, and brain congenital anomalies were clearly excluded. Data regarding the relationship between metabolite ratios in basal ganglia, thalamus, and white matter, and neurodevelopment were analysed. The quality assessment of included studies was performed according to the criteria from the QUADAS-2. N-acetylaspartate (NAA)/choline (Cho) was the most studied metabolite ratio. Lower NAA/Cho ratio in basal ganglia and thalamus was associated with adverse motor, cognitive, and language outcomes, and worse global neurodevelopment. Lower NAA/Cho ratio in white matter was associated with cognitive impairment. However, some associations came from single studies or were discordant among studies. The quality of included studies was low. 1H-MRS could be a promising tool for early diagnosis of neurodevelopmental impairment. However, further studies of good quality are needed to define the relationship between metabolite ratios and neurodevelopment.

Quantitative susceptibility mapping of basal ganglia iron is associated with cognitive and motor functions that distinguish spinocerebellar ataxia type 6 and type 3

Background

In spinocerebellar ataxia type 3 (SCA3), volume loss has been reported in the basal ganglia, an iron-rich brain region, but iron content has not been examined. Recent studies have reported that patients with SCA6 have markedly decreased iron content in the cerebellar dentate, coupled with severe volume loss. Changing brain iron levels can disrupt cognitive and motor functions, yet this has not been examined in the SCAs, a disease in which iron-rich regions are affected.

Methods

In the present study, we used quantitative susceptibility mapping (QSM) to measure tissue magnetic susceptibility (indicating iron concentration), structural volume, and normalized susceptibility mass (indicating iron content) in the cerebellar dentate and basal ganglia in people with SCA3 (n = 10) and SCA6 (n = 6) and healthy controls (n = 9). Data were acquired using a 7T Philips MRI scanner. Supplemental measures assessed motor, cognitive, and mood domains.

Results

Putamen volume was lower in both SCA groups relative to controls, replicating prior findings. Dentate susceptibility mass and volume in SCA6 was lower than in SCA3 or controls, also replicating prior findings. The novel finding was that higher basal ganglia susceptibility mass in SCA6 correlated with lower cognitive performance and greater motor impairment, an association that was not observed in SCA3. Cerebellar dentate susceptibility mass, however, had the opposite relationship with cognition and motor function in SCA6, suggesting that, as dentate iron is depleted, it relocated to the basal ganglia, which contributed to cognitive and motor decline. By contrast, basal ganglia volume loss, rather than iron content, appeared to drive changes in motor function in SCA3.

Conclusion

The associations of higher basal ganglia iron with lower motor and cognitive function in SCA6 but not in SCA3 suggest the potential for using brain iron deposition profiles beyond the cerebellar dentate to assess disease states within the cerebellar ataxias. Moreover, the role of the basal ganglia deserves greater attention as a contributor to pathologic and phenotypic changes associated with SCA.

Subcortical Aphasia

PURPOSE OF REVIEW

Subcortical structures have long been thought to play a role in language processing. Increasingly spirited debates on language studies, arising from as early as the nineteenth century, grew remarkably sophisticated as the years pass. In the context of non-thalamic aphasia, a few theoretical frameworks have been laid out. The disconnection hypothesis postulates that basal ganglia insults result in aphasia due to a rupture of connectivity between Broca and Wernicke's areas. A second viewpoint conjectures that the basal ganglia would more directly partake in language processing, and a third stream proclaims that aphasia would stem from cortical deafferentation. On the other hand, thalamic aphasia is more predominantly deemed as a resultant of diaschisis. This article reviews the above topics with recent findings on deep brain stimulation, neurophysiology, and aphasiology.

RECENT FINDINGS

The more recent approach conceptualizes non-thalamic aphasias as the offspring of unpredictable cortical hypoperfusion. Regarding the thalamus, there is mounting evidence now pointing to leading contributions of the pulvinar/lateral posterior nucleus and the anterior/ventral anterior thalamus to language disturbances. While the former appears to relate to lexical-semantic indiscrimination, the latter seems to bring about a severe breakdown in word selection and/or spontaneous top-down lexical-semantic operations. The characterization of subcortical aphasias and the role of the basal ganglia and thalamus in language processing continues to pose a challenge. Neuroimaging studies have pointed a path forward, and we believe that more recent methods such as tractography and connectivity studies will significantly expand our knowledge in this particular area of aphasiology.

Multi-model mapping of phonemic fluency

The voluntary generation of non-overlearned responses is usually assessed with phonemic fluency. Like most frontal tasks, it draws upon different complex processes and systems whose precise nature is still incompletely understood. Many claimed aspects regarding the pattern of phonemic fluency performance and its underlying anatomy remain controversial. Major limitations of past investigations include small sample size, scant analysis of phonemic output and methodologically insufficient lesion analysis approaches. We investigated a large number of patients with focal unilateral right or left frontal (n = 110) or posterior (n = 100) or subcortical (n = 65) lesions imaged with magnetic resonance or computed tomography and compared their performance on the number of overall responses, words produced over time, extremely infrequent/unknown words and inappropriate words generated. We also employed, for the first time parcel-based lesion-symptom mapping, tract-wise statistical analysis as well as Bayesian multi-variate analysis based on meta-analytically defined functional region of interest, including their interactions. We found that left frontal damage was associated with greater impairment than right frontal or posterior damage on overall fluency performance, suggesting that phonemic fluency shows specificity to frontal lesions. We also found that subcorticals, similar to frontals, performed significantly worse than posteriors on overall performance suggesting that subcortical regions are also involved. However, only frontal effects were found for words produced over time, extremely infrequent/unknown and inappropriate words. Parcel-based lesion-symptom mapping analysis found that worse fluency performance was associated with damage to the posterior segment of the left frontal middle and superior gyrus, the left dorsal anterior cingulate gyrus and caudate nucleus. Tract-wise statistical analysis revealed that disconnections of left frontal tracts are critical. Bayesian multi-variate models of lesions and disconnectome maps implicated left middle and inferior frontal and left dorsomedial frontal regions. Our study suggests that a set of well localized left frontal areas together with subcortical regions and several left frontal tracts are critical for word generation. We speculate that a left lateralized network exists. It involves medial, frontal regions supporting the process of 'energization', which sustains activation for the duration of the task and middle and inferior frontal regions concerned with 'selection', required due to the competition produced by associated stored words, respectively. The methodology adopted represents a promising and empirically robust approach in furthering our understanding of the neurocognitive architecture underpinning executive processes.

Social Cognition in Patients With Cerebellar Neurodegenerative Disorders

Objective

Cerebellar neurodegenerative disorders (CDs) are a heterogeneous group of disorders. It is known that the cerebellum plays a role not only in motor, but also in cognitive and social cognitive functions. The aim of this study was to investigate social cognition in patients with different CDs.

Materials and Methods

Social cognition was examined in 34 patients, 12 with spinocerebellar ataxia type 1 (SCA1), 6 with spinocerebellar ataxia type 2 (SCA2), and 16 with idiopathic late onset cerebellar ataxia (ILOCA). All patients were clinically evaluated using the Scale for the Rating and Assessment of Ataxia. In addition, 34 age, sex, and education-matched healthy control (HC) subjects were similarly analyzed. Social cognition was studied using two tests: the Faux Pas Recognition Test and the Reading the Mind in the Eyes Test (RMET). An appropriate array of neuropsychological tests was used to assess the global cognitive status as well as the frontal functions and mood.

Results

CD patients achieved significantly worse results on both tests of social cognition compared to the HCs. The SCA1 + 2 group achieved the poorest results on the Faux Pas Recognition Test and exhibited poor performance on all cognitive tests, but was only significantly worse compared to the ILOCA group on the Free and Cued Selective Reminding Test (FCSRT) – recognition. The patients in the SCA1 + 2 and ILOCA groups obtained similar scores on RMET. In the SCA1 + 2 group the findings significantly correlated with clinical parameters of disease severity and duration and executive functions (EFs), and with mood and executive functions in the ILOCA group. In the SCA group EFs appeared as the only significant predictor of RMET achievement. The Boston Naming Test (BTN) was a significant predictor of the CD patients’ achievement on RMET, while the BTN, the Trail Making Test Part A and FCSRT – Delayed free recall predicted their performance on the Faux Pas Recognition Test.

Conclusion

Patients with CD have social cognitive impairments as demonstrated by the Faux Pas Test and the RMET test results. The SCA1 and 2 patients exhibited a more pronounced impairment compared with the ILOCA patients. The independent cognitive predictors of social cognition impairment were EFs and language.

Lesion loci of impaired affective prosody: A systematic review of evidence from stroke

Affective prosody, or the changes in rate, rhythm, pitch, and loudness that convey emotion, has long been implicated as a function of the right hemisphere (RH), yet there is a dearth of literature identifying the specific neural regions associated with its processing. The current systematic review aimed to evaluate the evidence on affective prosody localization in the RH. One hundred and ninety articles from 1970 to February 2020 investigating affective prosody comprehension and production in patients with focal brain damage were identified via database searches. Eleven articles met inclusion criteria, passed quality reviews, and were analyzed for affective prosody localization. Acute, subacute, and chronic lesions demonstrated similar profile characteristics. Localized right antero-superior (i.e., dorsal stream) regions contributed to affective prosody production impairments, whereas damage to more postero-lateral (i.e., ventral stream) regions resulted in affective prosody comprehension deficits. This review provides support that distinct RH regions are vital for affective prosody comprehension and production, aligning with literature reporting RH activation for affective prosody processing in healthy adults as well. The impact of study design on resulting interpretations is discussed.

The Effect of Focal Damage to the Right Medial Posterior Cerebellum on Word and Sentence Comprehension and Production

Functional imaging studies of neurologically intact adults have demonstrated that the right posterior cerebellum is activated during verb generation, semantic processing, sentence processing, and verbal fluency. Studies of patients with cerebellar damage converge to show that the cerebellum supports sentence processing and verbal fluency. However, to date there are no patient studies that investigated the specific importance of the right posterior cerebellum in language processing, because: (i) case studies presented patients with lesions affecting the anterior cerebellum (with or without damage to the posterior cerebellum), and (ii) group studies combined patients with lesions to different cerebellar regions, without specifically reporting the effects of right posterior cerebellar damage. Here we investigated whether damage to the right posterior cerebellum is critical for sentence processing and verbal fluency in four patients with focal stroke damage to different parts of the right posterior cerebellum (all involving Crus II, and lobules VII and VIII). We examined detailed lesion location by going beyond common anatomical definitions of cerebellar anatomy (i.e., according to lobules or vascular territory), and employed a recently proposed functional parcellation of the cerebellum. All four patients experienced language difficulties that persisted for at least a month after stroke but three performed in the normal range within a year. In contrast, one patient with more damage to lobule IX than the other patients had profound long-lasting impairments in the comprehension and repetition of sentences, and the production of spoken sentences during picture description. Spoken and written word comprehension and visual recognition memory were also impaired, however, verbal fluency was within the normal range, together with object naming, visual perception and verbal short-term memory. This is the first study to show that focal damage to the right posterior cerebellum leads to language difficulties after stroke; and that processing impairments persisted in the case with most damage to lobule IX. We discuss these results in relation to current theories of cerebellar contribution to language processing. Overall, our study highlights the need for longitudinal studies of language function in patients with focal damage to different cerebellar regions, with functional imaging to understand the mechanisms that support recovery.