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.
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
regions of interest.
Patients with ALS exhibited global network alterations with decreased global efficiency (Eglob) (
= 0.03) and a trend of reduced whole brain mean degree (
= 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 (
< 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 (
< 0.01). Significant clinical correlations were identified between degree in the frontal area and the disease progression rate of ALS patients (
< 0.01).
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.
Background and purpose
Coronavirus disease 2019 (COVID‐19) is now known to cause neurological complications in both the central and the peripheral nervous system. Two new cases of typical neuralgic ...amyotrophy or Parsonage–Turner (PT) syndrome following coronavirus 2 infection (SARS‐CoV‐2) are reported here with explicit electrophysiological and imaging pathological features, underlining the possible association between COVID‐19 and PT syndrome.
Case reports
Case 1 was a 45‐year‐old schoolteacher presenting with acute pain in the right shoulder a few days after SARS‐CoV‐2 infection, with shoulder abduction and elbow flexion weakness. Needle electromyography showed a decrease in motor unit recruitment in the biceps brachii, and plexus magnetic resonance imaging (MRI) revealed a hyperintense signal involving the right C6 root and the superior truncus of the brachial plexus. Case 2 was a 21‐year‐old man hospitalized for dyspnea secondary to SARS‐CoV‐2 infection. Ten days after symptom onset, he presented right shoulder pain with difficulty in raising his right arm, revealing an isolated deficit of the serratus major muscle with a right scapula winging. Electrophysiological evaluation exhibited an isolated involvement of the long thoracic nerve with a neurogenic recruitment pattern in the serratus major muscle. Plexus MRI displayed a thickening and hyperintense signal involving the right long thoracic nerve.
Discussion
Parsonage–Turner syndrome triggered by SARS‐CoV‐2 seems to present clinical, electrophysiological and MRI characteristics similar to classic para‐infectious PT syndrome, including the time frame between viral infection and neurological symptom onset.
Conclusion
SARS‐CoV‐2 might be a new infectious trigger of PT syndrome.
Two acute painful shoulder weakness cases in coronavirus disease 2019 patients are presented, in favor of Parsonage–Turner (PT) syndrome secondary to coronavirus 2 infection (SARS‐CoV‐2). Analyzing our two cases, PT syndrome triggered by SARS‐CoV‐2 seems to present electrophysiological and magnetic resonance imaging characteristics similar to classical PT syndrome, including the time frame between viral infection and neurological symptom onset.
Background and Aim
Recreational use of nitrous oxide (N2O) has been associated with the development of severe nitrous oxide‐induced neuropathy (N2On). Follow‐up of these patients poses challenges, ...and their clinical progression remains largely unknown. The identification of prognostic factors is made difficult by the lack of standardized longitudinal assessments in most studies. The objective was to document the course of neuropathy through systematic follow‐up assessments in N2On patients to identify prognostic factors for persistent disability after 6 months.
Methods
We gathered demographic, clinical, biological, and electrophysiological data from N2On patients hospitalized in the Referral center in Marseille, both at baseline and during a standardized follow‐up assessment at 6 months.
Results
We retrospectively included 26 N2On patients (mean age 22.6 ± 4.4). Significant improvements were observed in all main clinical scores including Rankin, ONLS, and MRC testing (p < .01). Electrophysiological studies (EDX) revealed a predominantly motor neuropathy with marked reduction in CMAP in the lower limbs at baseline, and no significant improvement in motor parameters (p = .543). Rankin score at 6 months correlated with the initial weekly N2O consumption (r = .43, p = .03) and the CMAP sum score in the lower limbs at the first EDX (r = −.47, p = .02). Patients with and without myelitis showed similar Rankin and ONLS score after 6 months.
Interpretation
The clinical course generally improved favorably at 6 months with notable amelioration in the primary disability scores, sensory deficits, and ataxia. However, distal motor impairment associated with peripheral neuropathy persisted, with distal axonal loss emerging as the main prognostic factor for long‐term disability in these young patients.
Background and purposeCoronavirus disease 2019 (COVID-19) is now known to cause neurological complications in both the central and the peripheral nervous system. Two new cases of typical neuralgic ...amyotrophy or Parsonage–Turner (PT) syndrome following coronavirus 2 infection (SARS-CoV-2) are reported here with explicit electrophysiological and imaging pathological features, underlining the possible association between COVID-19 and PT syndrome.Case reportsCase 1 was a 45-year-old schoolteacher presenting with acute pain in the right shoulder a few days after SARS-CoV-2 infection, with shoulder abduction and elbow flexion weakness. Needle electromyography showed a decrease in motor unit recruitment in the biceps brachii, and plexus magnetic resonance imaging (MRI) revealed a hyperintense signal involving the right C6 root and the superior truncus of the brachial plexus. Case 2 was a 21-year-old man hospitalized for dyspnea secondary to SARS-CoV-2 infection. Ten days after symptom onset, he presented right shoulder pain with difficulty in raising his right arm, revealing an isolated deficit of the serratus major muscle with a right scapula winging. Electrophysiological evaluation exhibited an isolated involvement of the long thoracic nerve with a neurogenic recruitment pattern in the serratus major muscle. Plexus MRI displayed a thickening and hyperintense signal involving the right long thoracic nerve.DiscussionParsonage–Turner syndrome triggered by SARS-CoV-2 seems to present clinical, electrophysiological and MRI characteristics similar to classic para-infectious PT syndrome, including the time frame between viral infection and neurological symptom onset.ConclusionSARS-CoV-2 might be a new infectious trigger of PT syndrome.
Intramuscular fat fraction (FF) assessed using quantitative MRI (qMRI) has emerged as one of the few responsive outcome measures in CMT1A suitable for future clinical trials. This study aimed to ...identify the relevance of multiple qMRI biomarkers for tracking longitudinal changes in CMT1A and to assess correlations between MRI metrics and clinical parameters.
qMRI was performed in CMT1A patients at 2 time points, a year apart, and various metrics were extracted from 3-dimensional volumes of interest at thigh and leg levels. A semiautomated segmentation technique was used, enabling the analysis of central slices and a larger 3D muscle volume. Metrics included proton density (PD), magnetization transfer ratio (MTR), and intramuscular FF. The sciatic and tibial nerves were also assessed. Disease severity was gauged using Charcot Marie Tooth Neurologic Score (CMTNSv2), Charcot Marie Tooth Examination Score, Overall Neuropathy Limitation Scale scores, and Medical Research Council (MRC) muscle strength.
Twenty-four patients were included. FF significantly rose in the 3D volume at both thigh (+1.04% ± 2.19%,
= 0.041) and leg (+1.36% ± 1.87%,
= 0.045) levels. The 3D analyses unveiled a length-dependent gradient in FF, ranging from 22.61% ± 10.17% to 26.17% ± 10.79% at the leg level. There was noticeable variance in longitudinal changes between muscles: +3.17% ± 6.86% (
= 0.028) in the tibialis anterior compared with 0.37% ± 4.97% (
= 0.893) in the gastrocnemius medialis. MTR across the entire thigh volume showed a significant decline between the 2 time points -2.75 ± 6.58 (
= 0.049), whereas no significant differences were noted for the 3D muscle volume and PD. No longitudinal changes were observed in any nerve metric. Potent correlations were identified between FF and primary clinical measures: CMTNSv2 (ρ = 0.656;
= 0.001) and MRC in the lower limbs (ρ = -0.877;
< 0.001).
Our results further support that qMRI is a promising tool for following up longitudinal changes in CMT1A patients, FF being the paramount MRI metric for both thigh and leg regions. It is crucial to scrutinize the postimaging data extraction methods considering that annual changes are minimal (around +1.5%). Given the varied FF distribution, the existence of a length-dependent gradient, and the differential fatty involution across muscles, 3D volume analysis appeared more suitable than single slice analysis.
Objective
The objective of this study is to evaluate the frequency and characteristics of facial involvement in inclusion body myositis (IBM) patients and to compare it to the one previously ...described in facioscapulohumeral dystrophy (FSHD) patients.
Methods
Thirty-two IBM patients were included and compared to 29 controls and 39 FSHD patients. All participants were recorded in a video as they performed a series of seven facial tasks. Five raters independently assessed facial weakness using both a qualitative evaluation and a semi-quantitative facial weakness score (FWS).
Results
IBM patients had higher FWS than controls (7.89 ± 7.56 vs 1.06 ± 0.88,
p
< 0.001). Twenty IBM patients (63%) had a facial weakness with a FWS above the maximum value for controls. All facial tasks were significantly more impaired in IBM patients compared to controls (
p
< 0.001), task 2 evaluating orbiculari oculi muscle weakness being the most affected. IBM patients with facial weakness reported more swallowing troubles than IBM patients without facial weakness (
p
= 0.03). FSHD patients displayed higher FWS than IBM patients (12.16 ± 8.37 vs 7.89 ± 7.56,
p
= 0.01) with more pronounced facial asymmetry (
p
= 0.01). FWS inter-rater ICC was 0.775.
Conclusion
This study enabled us to estimate the frequency of facial impairment in IBM in more than half of patients, to detail its characteristics and to compare them with those of FSHD patients. The standardized, semi-quantitative FWS is an interesting diagnostic help in IBM as it appeared more sensitive than qualitative evaluation to detect mild facial weakness.
Les complications neurologiques secondaires à la consommation de protoxyde d’azote (N2O) sont de plus en plus fréquentes ces dernières années et associent des tableaux de neuropathies et/ou de ...myélopathies.
L’objectif de cette étude était d’établir les caractéristiques des patients présentant une myélopathie ou une neuropathie et de déterminer les mécanismes sous-jacents entraînant l’un ou l’autre de ces cadres nosologiques.
Dans cette étude observationnelle prospective, nous avons réalisé un ENMG et une IRM médullaire pour chaque patient hospitalisé pour un tableau neurologique secondaire à une consommation de N2O. Les patients ont été classés en neuromyélopathie (NM), myélopathie isolée (M) ou neuropathie isolée (N). La durée, la quantité de consommation, les scores cliniques, les paramètres biologiques, ainsi que les données électrophysiologiques (notamment les amplitudes motrices) et IRM (nombre de niveaux atteints) ont été recueillis.
Au total, 61 patients ont été inclus (45 % MN ; 34 % M ; 21 % N). En analyse multivariée, le risque de myélopathie était associé avec la quantité de consommation de N2O (p<0,05). L’étendue de la myélopathie était corrélée au nombre de N2O consommés (p<0,005). Le risque de neuropathie était associé à la durée de consommation (p<0,005). L’amplitude motrice des nerfs fibulaire et tibial était corrélée à la durée de consommation (p<0,05) (Tableau 1).
La quantité et la durée de consommation de N2O semble affecter la topographie de l’atteinte du système nerveux. L’atteinte médullaire semble dépendante de la quantité, et l’atteinte périphérique de la durée de consommation du N2O. L’inhibition massive de la B12 par le N2O semble être le mécanisme sous-tendant la myélopathie, et la répétition d’une hypoxie relative par inhalation de N2O pourrait expliquer celui de la neuropathie.
Cette étude observationnelle apporte les premiers résultats permettant d’appréhender les mécanismes physiopathologiques sous-jacents à l’une ou l’autre des atteintes neurologiques induites par la consommation aiguë ou chronique de protoxyde d’azote.
La fraction graisseuse intramusculaire (Fat Fraction=FF), évaluée par IRM quantitative (IRMq), a été identifiéé comme l’un des rares biomarqueurs suceptibles de montrer une évolution significative ...chez les patients CMT1A sur 1 an.
Identifier les biomarqueurs d’IRMq les plus sensibles aux changements longitudinaux chez les patients CMT1A, et évaluer leurs corrélations avec les principaux paramètres cliniques.
Vingt-deux patients CMT1A ont réalisé une IRMq des membres inférieurs à un an d’intervalle, afin d’analyser au niveau de la cuisse et de la jambe les biomarqueurs suivants : la densité de protons (PD), le transfert de magnétisation (MTR), le volume musculaire 3D et la FF. Les paramètres des nerfs fibulaire et tibial ont également été étudiés. La sévérité de la maladie a été mesurée à l’aide du testing MRC et des scores CMTNSv2, CMTES et ONLS.
Il existait une augmentation significative de la FF à la cuisse (+1,04±2,19 %, p=0,041) et à la jambe (+1,36±1,87 %, p=0,045) avec une hétérogénéité importante entre les différents muscles : +3,17±6,86 % (p=0,028) dans le tibial antérieur comparé à +0,37±4,97 % dans le gastrocnémien médial. Le MTR global de la cuisse montrait une diminution significative : −2,75±6,58 (p=0,049). Il existait d’importantes corrélations entre la FF et les scores cliniques : CMTNSv2 (rho=0,656 ; p=0,001) et MRC (rho=−0,877 ; p<0,001).
La FF reste le biomarqueur le plus sensible sur 1 an alors qu’aucune différence significative n’a été enregistrée pour le volume musculaire 3D, la DP et l’analyse des nerfs. Au vu des faibles variations retrouvées (+1,5 %), le développement de méthodes standardisées et précises d’extraction des données quantitatives est indispensable, et l’apport de l’intelligence artificielle dans ce domaine sera déterminant.
Cette étude confirme l’intérêt de l’IRMq pour évaluer des changements précoces chez les patients CMT1A. Ces biomarqueurs sensibles sur une courte période seront des outils d’évaluation importants en vue des futurs essais thérapeutiques dans cette pathologie.
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