Word retrieval in amyotrophic lateral sclerosis: a functional magnetic resonance imaging study

Frequency and Early Predictors of Cognitive Deterioration in Amyotrophic Lateral Sclerosis: A Longitudinal Population-Based Study

OBJECTIVE

The objective is to evaluate cognitive and behavioral progression and identify early predictors of these changes in a cohort of amyotrophic lateral sclerosis (ALS) patients.

METHODS

A total of 161 ALS patients were tested at diagnosis (T0), and 107 were re-tested after 1 year (T1) using cognitive/behavioral tests. All patients underwent whole-genome sequencing, and 46 patients (ALS-normal cognition [CN]) underwent [18F]Fluorodeoxyglucose positron emission tomography.

RESULTS

Of the 161 patients, 107 were re-rested at T1; non-retested patients included 10 with frontotemporal dementia and 44 who were either non-testable or deceased. At T0, 67 patients (62.6%) were classified as ALS-CN, whereas 40 (38.4%) showed some degree of cognitive/behavioral impairment. Eighteen ALS-CN patients (26.9%) experienced cognitive decline at T1. Phenoconverters had lower baseline scores in letter fluency (Letter Fluency Test [FAS]) (p < 0.001), Edinburgh Cognitive and Behavioral ALS Screen (ECAS) verbal fluency score (p = 0.017). Both tests were independently predictive of phenoconversion in binary logistic regression models, with optimal cut-off scores of 28.75 and 14.2, with good sensitivity and specificity. Other predictors included older age, lower education, and ALS-related genetic variants. Phenoconverters were hypometabolic in the left temporal lobe. Thirteen (32.5%) of the 40 patients with cognitive impairment at T0 worsened by T1, with FAS (p = 0.02) and the ECAS verbal fluency score (p = 0.023) predicting further decline.

INTERPRETATION

Approximately 30% of ALS patients experienced cognitive/behavioral decline within the first year after diagnosis. FAS and ECAS verbal fluency were predictive of cognitive phenoconversion. Our findings highlight the importance of early detection of at-risk individuals and the need for longitudinal cognitive assessments to monitor disease progression. ANN NEUROL 2025;97:1122-1133.

New developments in imaging in ALS

Neuroimaging in ALS has contributed considerable academic insights in recent years demonstrating genotype-specific topological changes decades before phenoconversion and characterising longitudinal propagation patterns in specific phenotypes. It has elucidated the radiological underpinnings of specific clinical phenomena such as pseudobulbar affect, apathy, behavioural change, spasticity, and language deficits. Academic concepts such as sexual dimorphism, motor reserve, cognitive reserve, adaptive changes, connectivity-based propagation, pathological stages, and compensatory mechanisms have also been evaluated by imaging. The underpinnings of extra-motor manifestations such as cerebellar, sensory, extrapyramidal and cognitive symptoms have been studied by purpose-designed imaging protocols. Clustering approaches have been implemented to uncover radiologically distinct disease subtypes and machine-learning models have been piloted to accurately classify individual patients into relevant diagnostic, phenotypic, and prognostic categories. Prediction models have been developed for survival in symptomatic patients and phenoconversion in asymptomatic mutation carriers. A range of novel imaging modalities have been implemented and 7 Tesla MRI platforms are increasingly being used in ALS studies. Non-ALS MND conditions, such as PLS, SBMA, and SMA, are now also being increasingly studied by quantitative neuroimaging approaches. A unifying theme of recent imaging papers is the departure from describing focal brain changes to focusing on dynamic structural and functional connectivity alterations. Progressive cortico-cortical, cortico-basal, cortico-cerebellar, cortico-bulbar, and cortico-spinal disconnection has been consistently demonstrated by recent studies and recognised as the primary driver of clinical decline. These studies have led the reconceptualisation of ALS as a "network" or "circuitry disease".

Adaptation and Validation of Version B of the Edinburgh Cognitive and Behavioural ALS Screen for the Portuguese Population

OBJECTIVE

This study aims to adapt and provide psychometric support for the validation of version B of the Edinburgh Cognitive and Behavioural ALS Screen (ECAS) for the Portuguese population, addressing the need for consistent cognitive evaluations in amyotrophic lateral sclerosis (ALS). A second culturally adapted ECAS screen facilitates the accurate characterization of ALS progression, mitigates learning effects, and supports tailored care management.

METHODS

The adaptation process included forward-backward translation, cultural adaptation, and cognitive debriefing on a prospective sample of 193 ALS patients and 106 controls. A multiple regression analysis identified predictors relevant for establishing ECAS cut-off scores. Psychometric evaluations, including reliability assessments and tests of convergent, construct, and criterion validity, were conducted. Additionally, version A's psychometric properties were reevaluated with complementary analyses and a larger sample.

RESULTS

Version B demonstrated good internal consistency with Cronbach's alpha of 0.802, comparable to the previously established version A. Moderate inter-item correlations further supported reliability, reflecting internal coherence. Equivalence testing between the Portuguese versions supported convergent validity, confirming version B's alignment with version A's theoretical framework. Exploratory factor analysis provided preliminary support for construct validity, and receiver operating characteristic analyses established cut-off values for both versions, revealing moderate sensitivity with a tendency toward false negatives, and higher specificity.

CONCLUSIONS

This study provided evidence for the cultural suitability, reliability, and validity of the Portuguese ECAS B. As evidence supports the equivalence of the Portuguese ECAS versions, they can be used for flexible screenings and applied with the calculated cut-off values to enhance diagnostic accuracy.

Mild cognitive impairment in amyotrophic lateral sclerosis: current view

Amyotrophic lateral sclerosis (ALS) is a fatal multi-system neurodegenerative disorder with no effective treatment or cure. Although primarily characterized by motor degeneration, cognitive dysfunction is an important non-motor symptom that has a negative impact on patient and caregiver burden. Mild cognitive deficits are present in a subgroup of non-demented patients with ALS, often preceding motor symptoms. Detailed neuropsychological assessments reveal deficits in a variety of cognitive domains, including those of verbal fluency and retrieval, language, executive function, attention and verbal memory. Mild cognitive impairment (MCI), a risk factor for developing dementia, affects between 10% and over 50% of ALS patients. Neuroimaging revealed atrophy of frontal and temporal cortices, disordered white matter Integrity, volume reduction in amygdala and thalamus, hypometabolism in the frontal and superior temporal gyrus and anterior insula. Neuronal loss in non-motor brain areas, associated with TDP-43 deposition, one of the morphological hallmarks of ALS, is linked to functional disruption of frontostriatal and frontotemporo-limbic connectivities as markers for cognitive deficits in ALS, the pathogenesis of which is still poorly understood. Early diagnosis by increased cerebrospinal fluid or serum levels of neurofilament light/heavy chain or glial fibrillary acidic protein awaits confirmation for MCI in ALS. These fluid biomarkers and early detection of brain connectivity signatures before structural changes will be helpful not only in establishing early premature diagnosis but also in clarifying the pathophysiological mechanisms of MCI in ALS, which might serve as novel targets for prohibition/delay and future adequate treatment of this debilitating disorder.

Sensory Dysfunction in ALS and Other Motor Neuron Diseases: Clinical Relevance, Histopathology, Neurophysiology, and Insights from Neuroimaging

Background: The clinical profiles of MNDs are dominated by inexorable motor decline, but subclinical proprioceptive, nociceptive and somatosensory deficits may also exacerbate mobility, dexterity, and bulbar function. While extra-motor pathology and frontotemporal involvement are widely recognised in motor neuron diseases (MNDs), reports of sensory involvement are conflicting. The potential contribution of sensory deficits to clinical disability is not firmly established and the spectrum of sensory manifestations is poorly characterised. Methods: A systematic review was conducted to examine the clinical, neuroimaging, electrophysiology and neuropathology evidence for sensory dysfunction in MND phenotypes. Results: In ALS, paraesthesia, pain, proprioceptive deficits and taste alterations are sporadically reported and there is also compelling electrophysiological, histological and imaging evidence of sensory network alterations. Gait impairment, impaired dexterity, and poor balance in ALS are likely to be multifactorial, with extrapyramidal, cerebellar, proprioceptive and vestibular deficits at play. Human imaging studies and animal models also confirm dorsal column-medial lemniscus pathway involvement as part of the disease process. Sensory symptoms are relatively common in spinal and bulbar muscular atrophy (SBMA) and Hereditary Spastic Paraplegia (HSP), but are inconsistently reported in primary lateral sclerosis (PLS) and in post-poliomyelitis syndrome (PPS). Conclusions: Establishing the prevalence and nature of sensory dysfunction across the spectrum of MNDs has a dual clinical and academic relevance. From a clinical perspective, subtle sensory deficits are likely to impact the disability profile and care needs of patients with MND. From an academic standpoint, sensory networks may be ideally suited to evaluate propagation patterns and the involvement of subcortical grey matter structures. Our review suggests that sensory dysfunction is an important albeit under-recognised facet of MND.

Impairments of inhibitory neurons in amyotrophic lateral sclerosis and frontotemporal dementia

Amyotrophic lateral sclerosis and frontotemporal dementia are two fatal neurodegenerative disorders. They are part of a pathophysiological continuum, displaying clinical, neuropathological, and genetic overlaps. There is compelling evidence that neuronal circuit dysfunction is an early feature of both diseases. Impaired neuronal excitability, imbalanced excitatory and inhibitory influences, and altered functional connectivity have been reported. These phenomena are likely due to combined alterations in the various cellular components involved in the functioning of neuronal networks. This review focuses on one of these cellular components: inhibitory neurons. We assess the evidence for inhibitory neuron impairments in amyotrophic lateral sclerosis and frontotemporal dementia, as well as the mechanisms leading to the loss of inhibition. We also discuss the contributions of these alterations to symptoms, and the potential therapeutic strategies for targeting inhibitory neuron deficits.

Metabolite alterations in the left dorsolateral prefrontal cortex and its association with cognitive assessments in amyotrophic lateral sclerosis: A longitudinal magnetic resonance spectroscopy study

OBJECTIVE

To characterize the longitudinal metabolite profile of the left dorsolateral prefrontal cortex (DLPFC) in amyotrophic lateral sclerosis (ALS) using magnetic resonance spectroscopy (MRS) and to examine its correlation with cognitive assessments.

METHODS

Thirteen patients at baseline and ten at follow-up, along with 14 age-, sex-, and handedness-matched healthy controls (HCs), were recruited. Three Tesla with a 64-channel coil, Point-RESolved Spectroscopy (PRESS) sequence (TR=1500 ms and TE=140 ms) was used. Metabolites in the left DLPFC were quantified using LCModel. Cognitive performance and functional impairment were assessed using the Edinburgh Cognitive and Behavioral ALS Screen (ECAS) and Revised ALS Functional Rating Scale (ALSFRS-R), respectively. Group comparisons were adjusted for multiple comparisons (p < 0.05, Bonferroni correction). The links between the brain metabolites and cognitive function were investigated using relevant correlation tests (Pearson's or Spearman's).

RESULTS

Our analysis revealed a significant difference in the choline-to-creatine ratio (tCho/tCr) among the three groups. Baseline ALS patients showed a higher tCho/tCr ratio than HCs (p = 0.033, Bonferroni-corrected). Interestingly, the total N-acetyl aspartate (tNAA)/tCr ratio, a marker of neuronal health, was strongly positively correlated with visuospatial cognitive scores at baseline and follow-up. Furthermore, at follow-up, tNAA/tCr was positively correlated with the total scores and specific sub-scores on the ECAS, encompassing both ALS-specific and non-specific cognitive domains. At follow-up, positive correlations emerged between tNAA/tCr and the total language and executive function scores.

CONCLUSIONS

Metabolite alterations and correlations with cognition were observed in the left DLPFC of ALS patients, supporting extra-motor involvement and its association with cognitive decline.

Verbal and nonverbal fluency in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a multi-system disorder that commonly affects cognition and behaviour. Verbal fluency impairments are consistently reported in ALS patients, and we aimed to investigate whether this deficit extends beyond the verbal domain. We further aimed to determine whether deficits are underpinned by a primary intrinsic response generation impairment (i.e., a global reduction across tasks), potentially related to apathy, or an inability to maintain responding over time (i.e., a 'drop off' pattern). Twenty-two ALS patients and 21 demographically-matched controls completed verbal and nonverbal fluency tasks (phonemic/semantic word fluency, design fluency, gesture fluency and ideational fluency), requiring the generation of responses over a specified time period. Fluency performance was analysed in terms of the overall number of novel items produced, as well as the number of items produced in the first 'initiation' and the remaining 'maintenance' time periods. ALS patients' overall performance was not globally reduced across tasks. Patients were impaired only on meaningful gesture fluency, which requires the generation of gestures that communicate meaning (e.g., waving). On phonemic fluency, ALS patients showed a 'drop off' pattern of performance, where they had difficulty maintaining responding over time, but this pattern was not evident on the other fluency tasks. Apathy did not appear to be related to fluency performance. The selective meaningful gesture fluency deficit, in the context of preserved meaningless gesture fluency, highlights that the retrieval of action knowledge may be weakened in early ALS.

Neuropsychological impairment in amyotrophic lateral sclerosis-frontotemporal spectrum disorder

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease with a rapid course, characterized by motor neuron dysfunction, leading to progressive disability and death. This Review, which is aimed at neurologists, psychologists and other health professionals who follow evidence-based practice relating to ALS and frontotemporal dementia (FTD), examines the neuropsychological evidence that has driven the reconceptualization of ALS as a spectrum disorder ranging from a pure motor phenotype to ALS-FTD. It focuses on changes in cognition and behaviour, which vary in severity across the spectrum: around 50% individuals with ALS are within the normal range, 15% meet the criteria for ALS-FTD, and the remaining 35% are in the mid-spectrum range with milder and more focal impairments. The cognitive impairments include deficits in verbal fluency, executive functions, social cognition and language, and apathy is the most prevalent behavioural change. The pattern and severity of cognitive and behavioural change predicts underlying regional cerebral dysfunction from brain imaging and post-mortem pathology. Our increased recognition of cognition and behaviour as part of the ALS phenotype has led to the development and standardization of assessment tools, which have been incorporated into research and clinical care. Measuring change over the course of the disease is vital for clinical trials, and neuropsychology is proving to be a biomarker for the earliest preclinical changes.

The Spectrum of Cognitive Dysfunction in Amyotrophic Lateral Sclerosis: An Update

Cognitive dysfunction is an important non-motor symptom in amyotrophic lateral sclerosis (ALS) that has a negative impact on survival and caregiver burden. It shows a wide spectrum ranging from subjective cognitive decline to frontotemporal dementia (FTD) and covers various cognitive domains, mainly executive/attention, language and verbal memory deficits. The frequency of cognitive impairment across the different ALS phenotypes ranges from 30% to 75%, with up to 45% fulfilling the criteria of FTD. Significant genetic, clinical, and pathological heterogeneity reflects deficits in various cognitive domains. Modern neuroimaging studies revealed frontotemporal degeneration and widespread involvement of limbic and white matter systems, with hypometabolism of the relevant areas. Morphological substrates are frontotemporal and hippocampal atrophy with synaptic loss, associated with TDP-43 and other co-pathologies, including tau deposition. Widespread functional disruptions of motor and extramotor networks, as well as of frontoparietal, frontostriatal and other connectivities, are markers for cognitive deficits in ALS. Cognitive reserve may moderate the effect of brain damage but is not protective against cognitive decline. The natural history of cognitive dysfunction in ALS and its relationship to FTD are not fully understood, although there is an overlap between the ALS variants and ALS-related frontotemporal syndromes, suggesting a differential vulnerability of motor and non-motor networks. An assessment of risks or the early detection of brain connectivity signatures before structural changes may be helpful in investigating the pathophysiological mechanisms of cognitive impairment in ALS, which might even serve as novel targets for effective disease-modifying therapies.

MRI biomarkers for memory-related impairment in amyotrophic lateral sclerosis: a systematic review

Introduction: Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder associated with cognitive and behavioral impairments and motor symptoms. Magnetic resonance imaging (MRI) biomarkers have been investigated as potential tools for detecting and monitoring memory-related impairment in ALS. Our objective was to examine the importance of identifying MRI biomarkers for memory-related impairment in ALS, motor neuron disease (MND), and ALS frontotemporal dementia (FTD) (ALS-FTD) patients. Methods: PubMed and Scopus databases were searched. Keywords covering magnetic resonance imaging, ALS, MND, and memory impairments were searched. There were a total of 25 studies included in our work here. Results: The structural MRI (sMRI) studies reported gray matter (GM) atrophy in the regions associated with memory processing, such as the hippocampus and parahippocampal gyrus (PhG), in ALS patients. The diffusion tensor imaging (DTI) studies showed white matter (WM) alterations in the corticospinal tract (CST) and other tracts that are related to motor and extra-motor functions, and these alterations were associated with memory and executive function impairments in ALS. The functional MRI (fMRI) studies also demonstrated an altered activation in the prefrontal cortex, limbic system, and other brain regions involved in memory and emotional processing in ALS patients. Conclusion: MRI biomarkers show promise in uncovering the neural mechanisms of memory-related impairment in ALS. Nonetheless, addressing challenges such as sample sizes, imaging protocols, and longitudinal studies is crucial for future research. Ultimately, MRI biomarkers have the potential to be a tool for detecting and monitoring memory-related impairments in ALS.

Longitudinal grey matter and metabolic contributions to cognitive changes in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis is characterized by rapidly evolving cognitive and brain impairments. While previous work revealed structural and functional alterations associated with cognitive decline in patients suffering from amyotrophic lateral sclerosis, the relationships between anatomo-functional changes and both disease's progression and the evolution of cognitive performance remain largely unexplored. Here, we took advantage of repeated multi-modal acquisitions in patients with amyotrophic lateral sclerosis over 1 year to assess the longitudinal sequence of grey matter atrophy, glucose metabolism and cognitive changes. Results revealed metabolic and structural changes over frontal, thalamic and temporal regions. Both cortical hypermetabolism and hypometabolism (right temporal gyrus and right angular gyrus, respectively) were associated with cognitive performance and thalamic hypometabolism during the follow-up testing session. Furthermore, the inferior frontal gyrus atrophy mediated the relation between early hypometabolism in this region and the subsequent decline of the theory of mind abilities. Marked volume loss was associated with larger hypometabolism and impaired cognitive performance. To our knowledge, this is the first study to longitudinally examine both grey matter volume and metabolic alteration patterns in patients with amyotrophic lateral sclerosis, over a mean follow-up time of 1 year. We identify how changes of the inferior frontal gyrus critically underly later cognitive performance, shedding new light on its high prognostic significance for amyotrophic lateral sclerosis-related changes. These results have important implications for our understanding of structural and functional changes associated with amyotrophic lateral sclerosis and how they underly cognitive impairments.

Cognitive reserve protects ALS-typical cognitive domains: A longitudinal study

BACKGROUND AND OBJECTIVES

To determine whether cognitive reserve (CR) as measured by verbal intelligence quotient, educational length, and achievement protects amyotrophic lateral sclerosis (ALS) patients' verbal fluency, executive functioning, and memory against brain volume loss over a period of 12 months.

METHODS

This cohort study was completed between 2013 and 2016 with a follow-up duration of 12 months. ALS patients were recruited from two specialist out-patient clinics in Rostock and Magdeburg in Germany. Participants underwent cognitive testing and magnetic resonance imaging both at baseline and again after 12 months. The cognitive domains assessed included verbal memory in addition to executive functions such as verbal fluency, working memory, shifting and selective attention.

RESULTS

Thirty-eight ALS patients took part; 25 patients had no cognitive impairment (ALSni), and 13 were cognitively impaired (ALSci). On average, patients lost 294 mm3 in their superior frontal gyri, 225 mm3 in their orbitofrontal gyri, and 15.97 mm3 in their hippocampi over 12 months. There was strong evidence that CR protected letter fluency from further decline (Bayes factor [BF] >10) and moderate evidence that it supported learning effects in letter flexibility (BF >3). However, there is a lack of evidence supporting the notion that working memory, shifting, selective attention or verbal memory (BF = 1) are protected.

DISCUSSION

As CR is easily determined and protects ALS-specific cognitive domains over time, it should be regarded as a valuable predictive marker.

Regulating Phase Transition in Neurodegenerative Diseases by Nuclear Import Receptors

RNA-binding proteins (RBPs) with a low-complexity prion-like domain (PLD) can undergo aberrant phase transitions and have been implicated in neurodegenerative diseases such as ALS and FTD. Several nuclear RBPs mislocalize to cytoplasmic inclusions in disease conditions. Impairment in nucleocytoplasmic transport is another major event observed in ageing and in neurodegenerative disorders. Nuclear import receptors (NIRs) regulate the nucleocytoplasmic transport of different RBPs bearing a nuclear localization signal by restoring their nuclear localization. NIRs can also specifically dissolve or prevent the aggregation and liquid–liquid phase separation of wild-type or disease-linked mutant RBPs, due to their chaperoning activity. This review focuses on the LLPS of intrinsically disordered proteins and the role of NIRs in regulating LLPS in neurodegeneration. This review also discusses the implication of NIRs as therapeutic agents in neurogenerative diseases.

Functional alterations in large-scale resting-state networks of amyotrophic lateral sclerosis: A multi-site study across Canada and the United States

Amyotrophic lateral sclerosis (ALS) is a multisystem neurodegenerative disorder characterized by progressive degeneration of upper motor neurons and lower motor neurons, and frontotemporal regions resulting in impaired bulbar, limb, and cognitive function. Magnetic resonance imaging studies have reported cortical and subcortical brain involvement in the pathophysiology of ALS. The present study investigates the functional integrity of resting-state networks (RSNs) and their importance in ALS. Intra- and inter-network resting-state functional connectivity (Rs-FC) was examined using an independent component analysis approach in a large multi-center cohort. A total of 235 subjects (120 ALS patients; 115 healthy controls (HC) were recruited across North America through the Canadian ALS Neuroimaging Consortium (CALSNIC). Intra-network and inter-network Rs-FC was evaluated by the FSL-MELODIC and FSLNets software packages. As compared to HC, ALS patients displayed higher intra-network Rs-FC in the sensorimotor, default mode, right and left fronto-parietal, and orbitofrontal RSNs, and in previously undescribed networks including auditory, dorsal attention, basal ganglia, medial temporal, ventral streams, and cerebellum which negatively correlated with disease severity. Furthermore, ALS patients displayed higher inter-network Rs-FC between the orbitofrontal and basal ganglia RSNs which negatively correlated with cognitive impairment. In summary, in ALS there is an increase in intra- and inter-network functional connectivity of RSNs underpinning both motor and cognitive impairment. Moreover, the large multi-center CALSNIC dataset permitted the exploration of RSNs in unprecedented detail, revealing previously undescribed network involvement in ALS.

NLRP3 inflammasome as a key molecular target underlying cognitive resilience in amyotrophic lateral sclerosis

Up to 50% of amyotrophic lateral sclerosis patients present with cognitive deficits in addition to motor dysfunction, but the molecular mechanisms underlying diverse clinical and pathological presentations remain poorly understood. There is therefore an unmet need to identify molecular drivers of cognitive dysfunction to enable better therapeutic targeting and prognostication. To address this, we employed a non-biased approach to identify molecular targets using a deeply phenotyped, clinically stratified cohort of cognitively affected and unaffected brain regions from three brain regions of 13 amyotrophic lateral sclerosis patients with the same cognitive screening test performed during life. Using NanoString molecular barcoding as a sensitive mRNA sequencing technique on post-mortem tissue, we profiled a data-driven panel of 770 genes using the Neuropathology Panel, followed by region and cell type-specific validation using BaseScope in situ hybridisation and immunohistochemistry. We identified 50 significantly dysregulated genes that are distinct between cognitively affected and unaffected brain regions. Using BaseScope in situ hybridisation, we also demonstrate that macromolecular complex regulation, notably NLRP3 inflammasome modulation, is a potential, therapeutically targetable, pathological correlate of cognitive resilience in ALS. © 2021 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd on behalf of The Pathological Society of Great Britain and Ireland.

VoxelHop: Successive Subspace Learning for ALS Disease Classification Using Structural MRI

Deep learning has great potential for accurate detection and classification of diseases with medical imaging data, but the performance is often limited by the number of training datasets and memory requirements. In addition, many deep learning models are considered a "black-box," thereby often limiting their adoption in clinical applications. To address this, we present a successive subspace learning model, termed VoxelHop, for accurate classification of Amyotrophic Lateral Sclerosis (ALS) using T2-weighted structural MRI data. Compared with popular convolutional neural network (CNN) architectures, VoxelHop has modular and transparent structures with fewer parameters without any backpropagation, so it is well-suited to small dataset size and 3D imaging data. Our VoxelHop has four key components, including (1) sequential expansion of near-to-far neighborhood for multi-channel 3D data; (2) subspace approximation for unsupervised dimension reduction; (3) label-assisted regression for supervised dimension reduction; and (4) concatenation of features and classification between controls and patients. Our experimental results demonstrate that our framework using a total of 20 controls and 26 patients achieves an accuracy of 93.48 % and an AUC score of 0.9394 in differentiating patients from controls, even with a relatively small number of datasets, showing its robustness and effectiveness. Our thorough evaluations also show its validity and superiority to the state-of-the-art 3D CNN classification approaches. Our framework can easily be generalized to other classification tasks using different imaging modalities.

Cortical activation and functional connectivity during the verbal fluency task for adolescent-onset depression: A multi-channel NIRS study

OBJECTIVE

Depression disorder is accompanied by cognitive impairments. However, there is limited research focused on cognitive impairments and their neurological mechanism in adolescents with depression. The purpose of the current study is to illustrate the differences in brain activity patterns between depressed adolescents and healthy controls (HCs).

METHOD

A total of 72 adolescents with depression, as well as 74 HCs, were recruited. We utilized functional near-infrared spectroscopy (fNIRS) to monitor the concentrations of oxyhemoglobin (Oxy-Hb) in the brains of participants while they performed the verbal fluency task (VFT) to examine cognitive impairment in adolescents with depression.

RESULTS

Our study demonstrated that adolescents with depression had significantly less cortical activation in the hemodynamic responses of Oxy-Hb at channels mainly located in the prefrontal cortex (PFC) than HCs during the 60-s task period (false discovery rate (FDR)-corrected p < 0.05). The mean channel-to-channel connectivity was 0.400 for HCs (SD = 0.149) and 0.303 (SD = 0.138) for adolescents with depression, and the HC group had a higher mean channel-to-channel connectivity strength than the depression group (t = -15.586, p < 0.001). For the patient group, we found significant negative correlations between HAMD scores and mean Oxy-Hb changes in Channel 38 (r = -0.33, p < 0.01), Channel 39 (r = -0.34, p < 0.01), Channel 41 (r = -0.25, p < 0.05), Channel 42 (r = -0.28, p < 0.05), and Channel 44 (r = -0.27, p < 0.05), and these channels were mainly located in areas with little difference between groups.

CONCLUSIONS

Our study provides neurological evidence about the executive function (EF) in depressed adolescents. Adolescents with depression exhibited an abnormal activation pattern and decreased task-related functional connectivity compared to HCs. The changed Oxy-Hb concentration of PFC during VFT was not sensitive to depression symptoms.

Site-specific mitochondrial dysfunction in neurodegeneration

Mitochondria are essential for neuronal survival and mitochondrial dysfunction is a hallmark of neurodegeneration. The loss in mitochondrial energy production, oxidative stress, and changes in calcium handling are associated with neurodegenerative diseases; however, different sites and types of mitochondrial dysfunction are linked to distinct neuropathologies. Understanding the causal or correlative relationship between changes in mitochondria and neuropathology will lead to new therapeutic strategies. Here, we summarize the evidence of site-specific mitochondrial dysfunction and mitochondrial-related clinical trials for neurodegenerative diseases. We further discuss potential therapeutic approaches, such as mitochondrial transplantation, restoration of mitochondrial function, and pharmacological alleviation of mitochondrial dysfunction.

Patterns of Language Impairment in Early Amyotrophic Lateral Sclerosis

Objective

To investigate the incidence and nature of language change and its relationship to executive dysfunction in a population-based incident amyotrophic lateral sclerosis (ALS) sample, with the hypothesis that patterns of frontotemporal involvement in early ALS extend beyond areas of executive control to regions associated with language processing.

Methods

One hundred seventeen population-based incident ALS cases without dementia and 100 controls matched by age, sex, and education were included in the study. A detailed assessment of language processing including lexical processing, word spelling, word reading, word naming, semantic processing, and syntactic/grammatical processing was undertaken. Executive domains of phonemic verbal fluency, working memory, problem-solving, cognitive flexibility, and social cognition were also evaluated.

Results

Language processing was impaired in this incident cohort of individuals with ALS, with deficits in the domains of word naming, orthographic processing, and syntactic/grammatical processing. Conversely, phonological lexical processing and semantic processing were spared. Although executive dysfunction accounted in part for impairments in grammatical and orthographic lexical processing, word spelling, reading, and naming, primary language deficits were also present.

Conclusions

Language impairment is characteristic of ALS at early stages of the disease and can develop independently of executive dysfunction, reflecting selective patterns of frontotemporal involvement at disease onset. Language change is therefore an important component of the frontotemporal syndrome associated with ALS.

Frontotemporal Pathology in Motor Neuron Disease Phenotypes: Insights From Neuroimaging

Frontotemporal involvement has been extensively investigated in amyotrophic lateral sclerosis (ALS) but remains relatively poorly characterized in other motor neuron disease (MND) phenotypes such as primary lateral sclerosis (PLS), progressive muscular atrophy (PMA), spinal muscular atrophy (SMA), spinal bulbar muscular atrophy (SBMA), post poliomyelitis syndrome (PPS), and hereditary spastic paraplegia (HSP). This review focuses on insights from structural, metabolic, and functional neuroimaging studies that have advanced our understanding of extra-motor disease burden in these phenotypes. The imaging literature is limited in the majority of these conditions and frontotemporal involvement has been primarily evaluated by neuropsychology and post mortem studies. Existing imaging studies reveal that frontotemporal degeneration can be readily detected in ALS and PLS, varying degree of frontotemporal pathology may be captured in PMA, SBMA, and HSP, SMA exhibits cerebral involvement without regional predilection, and there is limited evidence for cerebral changes in PPS. Our review confirms the heterogeneity extra-motor pathology across the spectrum of MNDs and highlights the role of neuroimaging in characterizing anatomical patterns of disease burden in vivo. Despite the contribution of neuroimaging to MND research, sample size limitations, inclusion bias, attrition rates in longitudinal studies, and methodological constraints need to be carefully considered. Frontotemporal involvement is a quintessential clinical facet of MND which has important implications for screening practices, individualized management strategies, participation in clinical trials, caregiver burden, and resource allocation. The academic relevance of imaging frontotemporal pathology in MND spans from the identification of genetic variants, through the ascertainment of presymptomatic changes to the design of future epidemiology studies.

Non-Motor Symptoms of Amyotrophic Lateral Sclerosis: A Multi-Faceted Disorder

Amyotrophic Lateral Sclerosis (ALS) is a fatal neurodegenerative disease characterized by progressive degeneration of motor pathways. A growing body of evidence from recent years suggests that ALS results in a wide range of non-motor symptoms as well, which can have a significant impact on patients' quality of life. These symptoms could also, in turn, provide useful information as biomarkers for disease progression, and can shed insight on ALS mechanisms. Here we aim to review a wide range of non-motor symptoms of ALS, with emphasis on their importance to research and clinical treatment of patients.

Does embodied cognition allow a better management of neurological diseases? A review on the link between cognitive language processing and motor function

Embodied cognition (EC) refers to the interplay occurring in thinking among individual's sensorimotor capacities (i.e., the ability of the body to respond to its senses with movement), the body itself, and the environment. The aim of the present narrative review is to provide an overall understanding of whether and how motor training could lead to language recovery, consistently with EC theories (action-perception cycle, mirror neuron systems -MNS-, and embodied semantics). We therefore reviewed the works dealing with EC in terms of the link between language processing, mirror neuron system (MNS), and motor function, evaluating the potential clinical implications for better managing neurological deficits. Connections between body and mind were found, as body states influence cognitive functions, such as perception and reasoning, as well as language processing, especially in neurological disorders. In fact, abnormalities in "embodied language" were found in movement disorders and neurodegenerative diseases, negatively affecting patients' rehabilitation outcomes. Understanding the link between language processing and motor outcomes is fundamental in the rehabilitation field, given that EC can be targeted to improve patients' functional recovery and quality of life.

Structural and functional underpinnings of precentral abnormalities in amyotrophic lateral sclerosis

BACKGROUND AND PURPOSE

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder characterized by the loss of both upper and lower motor neurons. Studies using various magnetic resonance imaging (MRI) analytical approaches have consistently identified significant precentral abnormalities in ALS, whereas their structural and functional underpinnings remain poorly understood.

METHODS

Using cortical thickness, fractional anisotropy (FA), and effective connectivity, we performed a multimodal MRI study to examine the structural and functional alterations associated with precentral abnormalities in patients with ALS (n = 60) compared with healthy controls (n = 60).

RESULTS

Cortical thickness analysis revealed significant cortical thinning in the right precentral gyrus (PCG), superior frontal gyrus, and superior temporal gyrus in patients with ALS. Tractwise white matter microstructure analyses revealed decreased FA in the tracts connected to the PCG cluster in patients with ALS involving the right corticospinal tract and the middle posterior body of the corpus callosum. Additionally, the cortical thickness of the PCG cluster was found to be positively correlated with FA of the tracts connected to the PCG cluster, suggesting that these two structural features are tightly coupled. Using spectral dynamic causal modelling, effective connectivity analysis among the three regions with cortical thinning revealed decreased self-inhibitory influence in the PCG cluster in patients with ALS, which might be an endophenotypic manifestation of an imbalance in inhibitory and excitatory neurotransmitters in this region.

CONCLUSIONS

The present data shed new light on the structural and functional underpinnings of precentral abnormalities in ALS.

A novel hypothesis on metal dyshomeostasis and mitochondrial dysfunction in amyotrophic lateral sclerosis: Potential pathogenetic mechanism and therapeutic implications

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder characterized by motor dysfunctions resulting from the loss of upper (UMNs) and lower (LMNs) motor neurons. While ALS symptoms are coincidental with pathological changes in LMNs and UMNs, the causal relationship between the two is unclear. For example, research on the extra-motor symptoms associated with this condition suggests that an imbalance of metals, including copper, zinc, iron, and manganese, is initially induced in the sensory ganglia due to a malfunction of metal binding proteins and transporters. It is proposed that the resultant metal dyshomeostasis may promote mitochondrial dysfunction in the satellite glial cells of these sensory ganglia, causing sensory neuron disturbances and sensory symptoms. Sensory neuron hyperactivation can result in LMN impairments, while metal dyshomeostasis in spinal cord and brain stem parenchyma induces mitochondrial dysfunction in LMNs and UMNs. These events could prompt intracellular calcium dyshomeostasis, pathological TDP-43 formation, and reactive microglia with neuroinflammation, which in turn activate the apoptosis signaling pathways within the LMNs and UMNs. Our model suggests that the degeneration of LMNs and UMNs is incidental to the metal-induced changes in the spinal cord and brain stem. Over time psychiatric symptoms may appear as the metal dyshomeostasis and mitochondrial dysfunction affect other brain regions, including the reticular formation, hippocampus, and prefrontal cortex. It is proposed that metal dyshomeostasis in combination with mitochondrial dysfunction could be the underlying mechanism responsible for the initiation and progression of the pathological changes associated with both the motor and extra-motor symptoms of ALS.

Progression of brain functional connectivity and frontal cognitive dysfunction in ALS

OBJECTIVE

To investigate the progression of resting-state functional connectivity (rs-FC) changes in patients with amyotrophic lateral sclerosis (ALS) and their relationship with frontal cognitive alterations.

METHODS

This is a multicentre, observational and longitudinal study. At baseline and after six months, 25 ALS patients underwent 3D T1-weighted MRI, resting-state functional MRI (rs-fMRI), and the computerized Test of Attentional Performance (TAP). Using independent component analysis, rs-FC changes of brain networks involving connections to frontal lobes and their relationship with baseline cognitive scores and cognitive changes over time were assessed. With a seed-based approach, rs-FC longitudinal changes of the middle frontal gyrus (MFG) were also explored.

RESULTS

After six months, ALS patients showed an increased rs-FC of the left anterior cingulate, left middle frontal gyrus (MFG) and left superior frontal gyrus within the frontostriatal network, and of the left MFG, left supramarginal gyrus and right angular gyrus within the left frontoparietal network. Within the frontostriatal network, a worse baseline performance at TAP divided attention task was associated with an increased rs-FC over time in the left MFG and a worse baseline performance at the category fluency index was related with increased rs-FC over time in the left frontal superior gyrus. After six months, the seed-based rs-FC analysis of the MFG with the whole brain showed decreased rs-FC of the right MFG with frontoparietal regions in patients compared to controls.

CONCLUSIONS

Rs-FC changes in ALS patients progressed over time within the frontostriatal and the frontoparietal networks and are related to frontal-executive dysfunction. The MFG seems a potential core region in the framework of a frontoparietal functional breakdown, which is typical of frontotemporal lobar degeneration. These findings offer new potential markers for monitoring extra-motor progression in ALS.

The spectrum of language impairments in amyotrophic lateral sclerosis

Language disorders are increasingly recognised in Amyotrophic lateral sclerosis (ALS), supporting the view of ALS as a multi-system disorder, impacting cognitive and motor function. However, the language impairments are heterogeneous and recent focus has been on determining the language profile across the ALS spectrum with little focus on spontaneous speech. The current study systematically investigated a wide range of language abilities in an unselected ALS sample (N = 22), including spontaneous speech. We analysed the ALS patients' performance as a group, compared to age-, education- and IQ-matched healthy controls (N = 21), and as a case series to identify dementia and specific language profiles. The ALS group was impaired on measures of spontaneous speech, word fluency and action naming. By contrast, object naming, semantic memory (object and actions), sentence comprehension and repetition (word and sentences) were comparable to healthy controls. In line with recent suggestions, our ALS patients' action naming (but not action semantic) deficit does not support the notion that action processing may be selectively impaired in ALS. The case series demonstrated that 14% of patients had probable dementia, 31% showed significant cognitive and/or language impairment and 55% were unimpaired, consistent with the spectrum of cognitive and language impairments reported in the literature. In addition, 36% of ALS patients produced significantly fewer words per minute on a spontaneous speech task than the control group, with this difference remaining when the ALS patients with frontotemporal dementia were excluded from the analysis. This pattern was observed across the ALS spectrum and in both limb and bulbar onset patients. The pattern of performance observed in the present study suggests that spontaneous speech is reduced across the ALS spectrum even in those with intact core language abilities.

Cognitive and behavioural impairment in amyotrophic lateral sclerosis

PURPOSE OF REVIEW

The current review provides an up to date overview of the nature and progression of the cognitive and behavioural impairment in amyotrophic lateral sclerosis (ALS). Understanding these symptoms has implications for the management of the disease and the design of clinical trials, in addition to the support of patient and caregiver regarding mental capacity and end of life decision-making.

RECENT FINDINGS

Cognitive and behavioural change in ALS are best characterized as the consequence of extensive network dysfunction. 35-45% of ALS patients present with mild-moderate cognitive impairment and comorbid dementia occurs in approximately 14% of patients, the majority of these meeting diagnostic criteria for frontotemporal dementia (FTD). Cognitive change in ALS manifests most commonly as executive dysfunction and language impairment. Behavioural change in the form of apathy, disinhibition, loss of sympathy and empathy, stereotyped behaviours and dietary changes occur.

SUMMARY

Cognitive and behavioural impairment is an important feature of ALS, and reflects broad network dysfunction of frontostriatal and frontotemporal systems. Cognition and behaviour should be assessed early in the diagnostic process, and data driven approaches should be developed to enable reliable quantitative outcome assessment suitable for clinical trials.

The Relationship between Selected Demographic Factors and Speech Organ Dysfunction in Sporadic ALS Patients

Background and objectives: Speech disorders are observed in 30% of newly diagnosed sporadic amyotrophic lateral sclerosis (ALS) patients. Characterized by a dynamic course, dysfunction of articulation has not so far been well understood. The aim of this study was to analyze the influence of demographic factors (sex, age, duration of the disease) and concomitant diseases (degenerative spine disease, depression, hypertension, hypothyroidism, hyperthyroidism, and allergy) on the functioning of speech organs in ALS patients. Materials and Methods: The study group consisted of 65 patients with sporadic ALS. Patients were examined for articulatory functions by means of the Frenchay Dysarthria Assessment (FDA). Results: 68% of the study sample had spinal disorders. Logistic regression analysis showed that a decline in the functioning of lips, soft palate, length of phonation, and voice loudness was more common among men. Patients diagnosed with degenerative spine disease more often suffered from respiratory disorders, while younger patients (<60 years of age) significantly more often had the impairment of the sentence and spontaneous speech functions. Conclusions: The male gender in patients with ALS is associated with an increased risk of deterioration of the phonation length function. Patients under 60 years of age are associated with more often pronouncing sentences disorders and spontaneous speech disorders.

Cortical thinning trajectories across disease stages and cognitive impairment in amyotrophic lateral sclerosis

BACKGROUND

Cortical neuron degenerative process underlying upper motor neuron involvement in amyotrophic lateral sclerosis (ALS) spreads to extra-motor regions as disease progresses. This is associated with cognitive and behavioural worsening in more severe disease stages. However, the clinical variability of ALS patients might reflect different cortical involvement in extra-motor areas.

OBJECTIVES

To investigate cortical thinning across disease stages in ALS patients accounting for their cognitive/behavioural impairment.

METHODS

Thirty-six ALS patients (17 with cognitive/behavioural impairment, ALSimp) and 26 healthy controls underwent structural 3T magnetic resonance imaging. Cortical thickness was measured with a region-wise approach. The King's Clinical Staging System was used to determine disease stages. The Jonckheere-Terpstra test tested for trends in cortical thinning and cognitive involvement across disease stages.

RESULTS

Significant trends toward cortical atrophy across disease stages were found in bilateral frontal and cingular cortex, left temporal gyrus and right occipital gyrus of ALS patients, consistently with cognitive impairment in phonemic fluency, language, verbal episodic memory and social cognition. Sub-group analyses revealed that ALSimp had specific thinning in the right fronto-temporal insular cortex related to more pronounced cognitive involvement.

CONCLUSION

Looking at ALS patients irrespective of their cognitive phenotype, motor and extra-motor cortical involvement is consistent with neuropathological studies of disease dissemination. Segregating patients according to their cognitive status, a distinctive trajectory of cortical thinning emerged for ALSimp patients, suggesting a specific course distinct to that of the classic ALS phenotype.

Longitudinal changes in resting state networks in early presymptomatic carriers of C9orf72 expansions

Previous cross-sectional imaging studies found differences in brain structure and in resting state networks between presymptomatic carriers of mutations in C9orf72 (C9+) and healthy controls. We carried out a prospective longitudinal study of clinical and resting state functional imaging in a cohort of 15 presymptomatic C9+ carriers to determine whether differences in resting state connectivity prior to developing symptoms reflect static developmental differences or ongoing low-grade degenerative changes. Presymptomatic C9+ carriers were scanned at baseline with follow-up scanning at 6- and 18-months and compared to a cohort of 14 healthy controls scanned longitudinally. Resting state networks associated with manifest disease were visualized by comparing 27 symptomatic C9+ carriers to 34 healthy controls. Motor, salience, thalamic, and speech production networks were visualized using a seed-based analysis. Neurofilament light chain was measured in serum obtained at the time of the scans. Neither clinical measures of motor, cognitive, and behavioral function nor neurofilament levels changed over follow-up in presymptomatic C9+ carriers. In thalamic networks, there was a reduction in connectivity in presymptomatic carriers at all timepoints with a constant difference compared to healthy controls. In contrast, precuneus/posterior cingulate regions exhibited declining functional connectivity compared to controls over the 18-month follow-up, particularly in motor networks. These were regions that also exhibited reduced functional connectivity in symptomatic C9+ carriers. Reduced connectivity over time also occurred in small regions of frontal and temporal cortex within salience and thalamic networks in presymptomatic C9+ carriers. A few areas of increased connectivity occurred, including cortex near the motor seed and within the speech production network. Overall, changes in functional connectivity over time favor the explanation of ongoing low-grade alterations in presymptomatic C9+ carriers in most networks, with the exception of thalamic networks where functional connectivity reductions were stable over time. The loss of connectivity to parietal cortex regions in several different networks may be a distinct feature of C9orf72-related degeneration. Longitudinal studies of carriers who phenoconvert will be important to determine the prognostic significance of presymptomatic functional connectivity alterations.

Intrusion errors during verbal fluency task in amyotrophic lateral sclerosis

BACKGROUND

Numerous studies have noted the presence of a dysexecutive component of the ALS-FTD. The most widely replicated result refers to the significantly reduced verbal fluency of ALS patients when compared to healthy people. As ALS patients have motor alterations that interfere with production, qualitative studies have the advantage of being independent of the degree of motor disability and revealing patients' cognitive state. This study examined the production differences between 42 ALS patients who presented with different degrees of dementia and motor impairment and 42 healthy people. Production processes were studied by extending the administration time of a letter fluency task to 2 minutes for the phonemic verbal fluency (PVF) and semantic verbal fluency (SVF) categories. This ensured that the qualitative aspects of verbal fluency were addressed, paying special attention to the new perseverations and intrusions, as well as any clinical correlates that may exist.

RESULTS

The ALS patients produced a significantly lower number of responses in PVF (p = .017) and SVF (p = .008). The rest of the indicators for frontal lobe alteration also suggested the existence of a dysfunction. The most remarkable results were the number of intrusions on the PVF task, which was much higher in the ALS group (p = .002). However, the number of perseverations did not differ significantly.

CONCLUSIONS

This study highlights the value of intrusions in addressing cognitive deterioration in ALS patients. This deterioration seems to be independent of the degree of motor impairment and of behavioural alterations. Therefore, the value of the intromissions on the verbal fluency task was highlighted as an indicator of a new cognitive alteration, which can be easily evaluated, even retrospectively.

Congenital Oral Masses: An Anatomic Approach to Diagnosis

Although congenital oral masses are rare, they are readily detectable during fetal US screening. Most congenital oral masses are benign, but some may cause mechanical airway obstruction, resulting in poor outcomes at delivery. The radiologist's ability to describe these abnormalities and their physiologic sequelae accurately can have a substantial effect on perinatal treatment. Furthermore, despite being rare, congenital oral lesions encountered at screening and at follow up fetal MRI provide the opportunity to make a specific diagnosis by following a simple anatomic approach. This article describes an anatomic algorithm as the framework for accurate diagnosis of congenital oral lesions. The imaging appearance of the most common congenital oral cavity neoplasms is outlined, including vascular anomalies, epulides, choristomas, congenital lingual thyroid anomalies, lingual hamartomas, and epignathi, and other conditions that mimic these at US. Also reviewed are perinatal management of masses that affect the fetal airway and the imaging features key to optimizing delivery outcomes. Online supplemental material is available for this article. ^©RSNA, 2019.

Spectroscopic markers of neurodegeneration in the mesial prefrontal cortex predict survival in ALS

Background and objective: N-acetylaspartate (NAA) and myo-inositol (mIns) are spectroscopic markers of neuronal integrity and astrogliosis, respectively. We performed a survival analysis to determine the prognostic value of the NAA/mIns metabolite ratio in ALS after a period of two and five years. Methods: Twenty-four patients with ALS (two with ALS-FTD) were recruited to participate in a high-field MR spectroscopy study of the mesial prefrontal cortex. Univariate and multivariate Cox proportional hazards analyses were used to assess NAA/mIns as a predictor of survival alongside other demographic and clinical measures. Census dates were set at two and five years after the time of MR scan for each patient. Survival curves were calculated using the Kaplan-Meier method. Results: After a five-year observation period, 19 patients had died and five were still alive. Median survival time from date of scan was 1.95 years. Univariate and multivariate Cox analysis showed NAA/mIns to be a significant independent predictor of survival at two years after scanning, but not at five years. Conclusion: Cerebral degeneration in the mesial prefrontal cortex as detected by the NAA/mIns metabolite ratio is predictive of survival in ALS in a time-dependent manner.

Executive, language and fluency dysfunction are markers of localised TDP-43 cerebral pathology in non-demented ALS

OBJECTIVE

Approximately 35% of patients with amyotrophic lateral sclerosis (ALS) exhibit mild cognitive deficits in executive functions, language and fluency, without dementia. The precise pathology of these extramotor symptoms has remained unknown. This study aimed to determine the pathological correlate of cognitive impairment in patients with non-demented ALS.

METHODS

In-depth neuropathological analysis of 27 patients with non-demented ALS who had undergone cognitive testing (Edinburgh Cognitive and Behaviour ALS Screen (ECAS)) during life. Analysis involved assessing 43 kDa Tar-DNA binding protein (TDP-43) accumulation in brain regions specifically involved in executive functions, language functions and verbal fluency to ascertain whether functional deficits would relate to a specific regional distribution of pathology.

RESULTS

All patients with cognitive impairment had TDP-43 pathology in extramotor brain regions (positive predictive value of 100%). The ECAS also predicted TDP-43 pathology with 100% specificity in brain regions associated with executive, language and fluency domains. We also detected a subgroup with no cognitive dysfunction, despite having substantial TDP-43 pathology, so called mismatch cases.

CONCLUSIONS

Cognitive impairment as detected by the ECAS is a valid predictor of TDP-43 pathology in non-demented ALS. The profile of mild cognitive deficits specifically predicts regional cerebral involvement. These findings highlight the utility of the ECAS in accurately assessing the pathological burden of disease.

An exploration of neural dynamics of motor imagery for people with amyotrophic lateral sclerosis

OBJECTIVE

Studies of the neuropathological effects of amyotrophic lateral sclerosis (ALS) on the underlying motor system have investigated abnormalities in the magnitude and timing of the event-related desynchronization (ERD) and synchronization (ERS) during motor execution (ME). However, the spatio-spectral-temporal dynamics of these sensorimotor oscillations during motor imagery (MI) have not been fully explored for these patients. This study explores the neural dynamics of sensorimotor oscillations for ALS patients during MI by quantifying ERD/ERS features in frequency, time, and space.

APPROACH

Electroencephalogram (EEG) data were recorded from six patients with ALS and 11 age-matched healthy controls (HC) while performing a MI task. ERD/ERS features were extracted using wavelet-based time-frequency analysis and compared between the two groups to quantify the abnormal neural dynamics of ALS in terms of both time and frequency. Topographic correlation analysis was conducted to compare the localization of MI activity between groups and to identify subject-specific frequencies in the µ and β frequency bands.

MAIN RESULTS

Overall, reduced and delayed ERD was observed for ALS patients, particularly during right-hand MI. ERD features were also correlated with ALS clinical scores, specifically disease duration, bulbar, and cognitive functions.

SIGNIFICANCE

The analyses in this study quantify abnormalities in the magnitude and timing of sensorimotor oscillations for ALS patients during MI tasks. Our findings reveal notable differences between MI and existing results on ME in ALS. The observed alterations are speculated to reflect disruptions in the underlying cortical networks involved in MI functions. Quantifying the neural dynamics of MI plays an important role in the study of EEG-based cortical markers for ALS.

Structural Connectivity Alterations in Amyotrophic Lateral Sclerosis: A Graph Theory Based Imaging Study

Background

Amyotrophic lateral sclerosis (ALS) is a relentlessly progressive neurodegenerative disorder. Diffusion magnetic resonance imagining (MRI) studies have consistently showed widespread alterations in both motor and non-motor brain regions. However, connectomics and graph theory based approaches have shown inconsistent results. Hub-centered lesion patterns and their impact on local and large-scale brain networks remain to be established. The objective of this work is to characterize topological properties of structural brain connectivity in ALS using an array of local, global and hub-based network metrics.

Materials and Methods

Magnetic resonance imagining data were acquired from 25 patients with ALS and 26 age-matched healthy controls. Structural network graphs were constructed from diffusion tensor MRI. Network-based statistics (NBS) and graph theory metrics were used to compare structural networks without a priori regions of interest.

Results

Patients with ALS exhibited global network alterations with decreased global efficiency (Eglob) (p = 0.03) and a trend of reduced whole brain mean degree (p = 0.05) compared to controls. Six nodes showed significantly decreased mean degree in ALS: left postcentral gyrus, left interparietal and transverse parietal sulcus, left calcarine sulcus, left occipital temporal medial and lingual sulcus, right precentral gyrus and right frontal inferior sulcus (p < 0.01). Hub distribution was comparable between the two groups. There was no selective hub vulnerability or topological reorganization centered on these regions as the hub disruption index (κ) was not significant for the relevant metrics (degree, local efficiency and betweenness centrality). Using NBS, we identified an impaired motor subnetwork of 11 nodes and 10 edges centered on the precentral and the paracentral nodes (p < 0.01). Significant clinical correlations were identified between degree in the frontal area and the disease progression rate of ALS patients (p < 0.01).

Conclusion

Our study provides evidence that alterations of structural connectivity in ALS are primarily driven by node degree and white matter tract degeneration within an extended network around the precentral and the paracentral areas without hub-centered reorganization.

The Edinburgh cognitive and behavioral amyotrophic lateral sclerosis screen (ECAS): sensitivity in differentiating between ALS and Alzheimer's disease in a Greek population

Objectives: (1) Adapt the ECAS into Greek, validate it in ALS patients and compare with the ALS-CBS. (2) Determine the sensitivity and specificity of ECAS in the differentiation between AD and non-demented ALS patients as compared with the ACE-III and mini-ACE. Methods: ALS patients (n = 28) were recruited and AD patients (n = 26) were matched in age, sex, and education with ALS patients (n = 24). The normative data were derived from a random sample of controls (n = 52). Bayes correlation analysis was conducted to examine convergent validity. Bayes t-test was performed to assess between groups' differences. Receiver operating characteristics (ROC) curve analyses and area under the curve (AUC) were implemented to appraise the sensitivity and specificity in the differentiation between the AD and non-demented ALS patients. Results: The ECAS and its sub-scores in addition to the behavior interview demonstrated robust correlations with the ALS-CBS. Impairment in language and verbal fluency were the most prominent deficits in the ALS patients. The most frequently reported change was apathy. The ROC analysis demonstrated that the ECAS-ALS nonspecific score (comprising memory and visuospatial domains) is the most sensitive and specific in differentiating the AD from ALS patients. The other measures expressed high sensitivity, yet a poor specificity. Conclusions: The ECAS is a multi-purpose screening tool. The ECAS-ALS specific appraises the whole spectrum of the highly prevalent cognitive impairments in ALS. The ECAS-ALS nonspecific (memory and visuospatial) is a sensitive score to detect AD related deficits and is able to differentiate the AD from the non-demented ALS patients better than the ACE-III and mini-ACE.

Patterned functional network disruption in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease primarily affecting motor function, with additional evidence of extensive nonmotor involvement. Despite increasing recognition of the disease as a multisystem network disorder characterised by impaired connectivity, the precise neuroelectric characteristics of impaired cortical communication remain to be fully elucidated. Here, we characterise changes in functional connectivity using beamformer source analysis on resting‐state electroencephalography recordings from 74 ALS patients and 47 age‐matched healthy controls. Spatiospectral characteristics of network changes in the ALS patient group were quantified by spectral power, amplitude envelope correlation (co‐modulation) and imaginary coherence (synchrony). We show patterns of decreased spectral power in the occipital and temporal (δ‐ to β‐band), lateral/orbitofrontal (δ‐ to θ‐band) and sensorimotor (β‐band) regions of the brain in patients with ALS. Furthermore, we show increased co‐modulation of neural oscillations in the central and posterior (δ‐, θ‐ and γ_l‐band) and frontal (δ‐ and γ_l‐band) regions, as well as decreased synchrony in the temporal and frontal (δ‐ to β‐band) and sensorimotor (β‐band) regions. Factorisation of these complex connectivity patterns reveals a distinct disruption of both motor and nonmotor networks. The observed changes in connectivity correlated with structural MRI changes, functional motor scores and cognitive scores. Characteristic patterned changes of cortical function in ALS signify widespread disease‐associated network disruption, pointing to extensive dysfunction of both motor and cognitive networks. These statistically robust findings, that correlate with clinical scores, provide a strong rationale for further development as biomarkers of network disruption for future clinical trials.

SQSTM1/p62: A Potential Target for Neurodegenerative Disease

Neurodegenerative diseases, characterized by a progressive loss of brain function, affect the lives of millions of individuals worldwide. The complexity of the brain poses a challenge for scientists trying to map the biochemical and physiological pathways to identify areas of pathological errors. Brain samples of patients with neurodegenerative diseases have been shown to contain large amounts of misfolded and abnormally aggregated proteins, resulting in dysfunction in certain brain centers. Removal of these abnormal molecules is essential in maintaining protein homeostasis and overall neuronal health. Macroautophagy is a major route by which cells achieve this. Administration of certain autophagy-enhancing compounds has been shown to provide therapeutic effects for individuals with neurodegenerative conditions. SQSTM1/p62 is a scaffold protein closely involved in the macroautophagy process. p62 functions to anchor the ubiquitinated proteins to the autophagosome membrane, promoting degradation of unwanted molecules. Modulators targeting p62 to induce autophagy and promote its protective pathways for aggregate protein clearance have high potential in the treatment of these conditions. Additionally, causal relationships have been found between errors in regulation of SQSTM1/p62 and the development of a variety of neurodegenerative disorders, including Alzheimer's, Parkinson's, Huntington's, amyotrophic lateral sclerosis, and frontotemporal lobar degeneration. Furthermore, SQSTM1/p62 also serves as a signaling hub for multiple pathways associated with neurodegeneration, providing a potential therapeutic target in the treatment of neurodegenerative diseases. However, rational design of a p62-oriented autophagy modulator that can balance the negative and positive functions of multiple domains in p62 requires further efforts in the exploration of the protein structure and pathological basis.

Spinal Cord Imaging in Amyotrophic Lateral Sclerosis: Historical Concepts-Novel Techniques

Amyotrophic lateral sclerosis (ALS) is the most common adult onset motor neuron disease with no effective disease modifying therapies at present. Spinal cord degeneration is a hallmark feature of ALS, highlighted in the earliest descriptions of the disease by Lockhart Clarke and Jean-Martin Charcot. The anterior horns and corticospinal tracts are invariably affected in ALS, but up to recently it has been notoriously challenging to detect and characterize spinal pathology in vivo. With recent technological advances, spinal imaging now offers unique opportunities to appraise lower motor neuron degeneration, sensory involvement, metabolic alterations, and interneuron pathology in ALS. Quantitative spinal imaging in ALS has now been used in cross-sectional and longitudinal study designs, applied to presymptomatic mutation carriers, and utilized in machine learning applications. Despite its enormous clinical and academic potential, a number of physiological, technological, and methodological challenges limit the routine use of computational spinal imaging in ALS. In this review, we provide a comprehensive overview of emerging spinal cord imaging methods and discuss their advantages, drawbacks, and biomarker potential in clinical applications, clinical trial settings, monitoring, and prognostic roles.

Biomarkers in Motor Neuron Disease: A State of the Art Review

Motor neuron disease can be viewed as an umbrella term describing a heterogeneous group of conditions, all of which are relentlessly progressive and ultimately fatal. The average life expectancy is 2 years, but with a broad range of months to decades. Biomarker research deepens disease understanding through exploration of pathophysiological mechanisms which, in turn, highlights targets for novel therapies. It also allows differentiation of the disease population into sub-groups, which serves two general purposes: (a) provides clinicians with information to better guide their patients in terms of disease progression, and (b) guides clinical trial design so that an intervention may be shown to be effective if population variation is controlled for. Biomarkers also have the potential to provide monitoring during clinical trials to ensure target engagement. This review highlights biomarkers that have emerged from the fields of systemic measurements including biochemistry (blood, cerebrospinal fluid, and urine analysis); imaging and electrophysiology, and gives examples of how a combinatorial approach may yield the best results. We emphasize the importance of systematic sample collection and analysis, and the need to correlate biomarker findings with detailed phenotype and genotype data.

Pathological Crying and Laughing in Motor Neuron Disease: Pathobiology, Screening, Intervention

Pathological crying and laughing (PCL) has significant quality-of-life implications in amyotrophic lateral sclerosis (ALS); it can provoke restrictive life-style modifications and lead to social isolation. Despite its high prevalence and quality of life implications, it remains surprisingly understudied. Divergent pathophysiological models have been proposed, centered on corticobulbar tract degeneration, prefrontal cortex pathology, sensory deafferentation, and impaired cerebellar gate-control mechanisms. Quantitative MRI techniques and symptom-specific clinical instruments offer unprecedented opportunities to elucidate the anatomical underpinnings of PCL pathogenesis. Emerging neuroimaging studies of ALS support the role of cortico-pontine-cerebellar network dysfunction in context-inappropriate emotional responses. The characterization of PCL-associated pathophysiological processes is indispensable for the development of effective pharmacological therapies.

Functional reorganization during cognitive function tasks in patients with amyotrophic lateral sclerosis

Cognitive deficits, especially in the domains of social cognition and executive function including verbal fluency, are common in amyotrophic lateral sclerosis (ALS) patients. There is yet sparse understanding of pathogenesis of the underlying, possibly adaptive, cortical patterns. To address this issue, 65 patients with ALS and 33 age-, gender- and education-matched healthy controls were tested on cognitive and behavioral deficits with the Edinburgh Cognitive and Behavioural ALS Screen (ECAS). Using functional magnetic resonance imaging (fMRI), cortical activity during social cognition and executive function tasks (theory of mind, verbal fluency, alternation) adapted from the ECAS was determined in a 3 Tesla scanner. Compared to healthy controls, ALS patients performed worse in the ECAS overall (p < 0.001) and in all of its subdomains (p < 0.02), except memory. Imaging revealed altered cortical activation during all tasks, with patients consistently showing a hyperactivation in relevant brain areas compared to healthy controls. Additionally, cognitively high performing ALS patients consistently exhibited more activation in frontal brain areas than low performing patients and behaviorally unimpaired patients presented with more neuronal activity in orbitofrontal areas than behaviorally impaired patients. In conclusion, hyperactivation in fMRI cognitive tasks seems to represent an early adaptive process to overcome neuronal cell loss in relevant brain areas. The hereby presented cortical pattern change might suggest that, once this loss passes a critical threshold and no cortical buffering is possible, clinical representation of cognitive and behavioral impairment evolves. Future studies might shed light on the pattern of cortical pattern change in the course of ALS.

Regional Dynamics of the Resting Brain in Amyotrophic Lateral Sclerosis Using Fractional Amplitude of Low-Frequency Fluctuations and Regional Homogeneity Analyses

Resting-state functional magnetic resonance imaging has been playing an important role in the study of amyotrophic lateral sclerosis (ALS). Although functional connectivity is widely studied, the patterns of spontaneous neural activity of the resting brain are important mechanisms that have been used recently to study a variety of conditions but remain less explored in ALS. Here we have used fractional amplitude of low-frequency fluctuation (fALFF) and regional homogeneity (ReHo) to study the regional dynamics of the resting brain of nondemented ALS patients compared with healthy controls. As expected, we found the sensorimotor network with changes in fALFF and ReHo, and also found the default mode network (DMN), frontoparietal network (FPN), and salience network (SN) altered and the cerebellum, although no structural changes between ALS patients and controls were reported in the regions with fALFF and ReHo changes. We show an altered pattern in the spontaneous low-frequency oscillations that is not confined to the motor areas and reveal a more widespread involvement of nonmotor regions, including those responsible for cognition.