Publications by authors named "Jean Christophe Ouallet"

Background And Objectives: Progressive multifocal leukoencephalopathy (PML) is a severe neurologic disease resulting from JC virus reactivation in immunocompromised patients. Certain multiple sclerosis (MS) disease-modifying therapies (DMTs) are associated with PML risk, such as natalizumab and, more rarely, sphingosine-1-phosphate receptor modulators (S1P-RMs). Although natalizumab-associated PML is well documented, information on S1P-RM-associated PML is limited.

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Background: The gynaecological care of women with Multiple Sclerosis has received little attention; most reports focussed on pregnancy or sexuality. The objective of the present study was to evaluate if gynaecological follow-up for women of reproductive age with Multiple Sclerosis was adequate.

Methods: We performed a cross-sectional study on a large cohort of women with Multiple Sclerosis aged 18-40 years.

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Background And Objectives: Progressive multifocal leukoencephalopathy (PML) is a disabling neurologic disorder resulting from the infection of the CNS by JC polyomavirus in immunocompromised individuals. For the last 2 decades, increasing use of immunotherapies leads to iatrogenic PML. Iatrogenic PML is often associated with signs of inflammation at onset (inflammatory PML) and/or after treatment withdrawal immune reconstitution inflammatory syndrome (PML-IRIS).

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Objective: To determine whether adult cases of Chronic Lymphocytic Inflammation with Pontine Perivascular Enhancement Responsive to Steroids (CLIPPERS) may be related to familial hemophagocytic lymphohistiocytosis (HLH) causes, we have screened patients with adult-onset CLIPPERS for mutations in primary HLH-associated genes.

Methods: In our cohort of 36 patients fulfilling the criteria for probable or definite CLIPPERS according to the CLIPPERS-2017 criteria, we conducted a first study on 12 patients who consented to genetic testing. In these 12 patients, systemic HLH criteria were searched, and genetic analysis of 8 genes involved in primary HLH was performed.

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Introduction: Familial Mediterranean fever (FMF) is the most frequent monogenic autoinflammatory disorder; and leads to the uncontrolled production of interleukin (IL)-1β. Multiple sclerosis (MS) is an inflammatory disease of the central nervous system; and its development seems to be partly correlated with IL-1β levels. It is hypothesized that FMF could be associated with MS.

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Importance: Risk factors associated with the severity of coronavirus disease 2019 (COVID-19) in patients with multiple sclerosis (MS) are unknown. Disease-modifying therapies (DMTs) may modify the risk of developing a severe COVID-19 infection, beside identified risk factors such as age and comorbidities.

Objective: To describe the clinical characteristics and outcomes in patients with MS and COVID-19 and identify factors associated with COVID-19 severity.

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Introduction: No randomized controlled clinical trial of therapeutic plasma exchanges (TPE) has yet been performed for moderate-to-severe relapses of multiple sclerosis (MS).

Objective: To compare TPE to sham-TPE in patients with a recent steroid-resistant moderate-to-severe MS relapse.

Methods: Patients presenting with an MS relapse of less than 2 months without improvement and 15 days after a course of steroids were randomized.

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Article Synopsis
  • The study investigated emotional disorders in relapsing-remitting multiple sclerosis (RRMS) patients undergoing IFN-β treatment over 24 months, focusing on emotional control and related factors like fatigue, irritability, depression, and anxiety.
  • Out of 79 patients recruited, 70 were analyzed, revealing that while emotional control scores remained stable, younger age, male sex, and antidepressant use were linked to higher emotional control issues.
  • Overall, the study suggests that although no significant emotional disorders related to IFN-β were found in these patients, it's important to monitor for potential severe mood disorders and suicidality.
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The ideal treatment for multiple sclerosis (MS) would target both the neuroinflammatory component of the disease (peripheral and central) and its neurodegenerative component, via modulation of a ubiquitous and pleiotropic common target. Sphingosine-1-phosphate (S1P), a product of sphingosine metabolism, regulates many biological functions (including cell proliferation and survival, cell migration, the immune response and cardiovascular function) via five subtypes of receptor. These receptors are expressed in all types of brain cells where they modulate a number of processes involved in neuronal plasticity, including myelination, neurogenesis and neuroprotection.

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Article Synopsis
  • This study investigates very late-onset inflammatory demyelinating events (VLO-IDE) in patients over 70 years old, focusing on their clinical, biological, and radiological characteristics.
  • Conducted as a retrospective multicenter study, it involved 25 patients, predominantly female (F:M ratio 2.1:1), who often experienced severe spinal cord deficits and extensive lesions.
  • Results show that conditions like multiple sclerosis and neuromyelitis optica spectrum disorders are common, with a significant presence of severe motor impairment and active inflammatory lesions in this elderly population.
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Background: Cerebellar and cognitive dysfunction can occur early in clinically isolated syndrome (CIS). Eye tracking is a reliable tool for the evaluation of both subtle cerebellar symptoms and cognitive impairment.

Objectives: To investigate the early cognitive profile using neuropsychological and ocular motor (OM) testing in CIS with and without cerebellar dysfunction with OM testing compared to healthy subjects (HS).

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Background: The posterior cerebellar lobules seem to be the anatomical substrate of cognitive cerebellar processes, but their microstructural alterations in multiple sclerosis (MS) remain unclear.

Objectives: To correlate diffusion metrics in lobules VI to VIIIb in persons with clinically isolated syndrome (PwCIS) and in cognitively impaired persons with MS (CIPwMS) with their cognitive performances.

Methods: Sixty-nine patients (37 PwCIS, 32 CIPwMS) and 36 matched healthy subjects (HS) underwent 3T magnetic resonance imaging, including 3D T1-weighted and diffusion tensor imaging (DTI).

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Background: Therapeutic options are limited in secondary progressive multiple sclerosis (SPMS). Open-label studies suggested efficacy of monthly IV cyclophosphamide (CPM) without induction for delaying progression but no randomized trial was conducted so far.

Objective: To compare CPM to methylprednisolone (MP) in SPMS.

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Background: Cerebellar damage has been implicated in information processing speed (IPS) impairment associated with multiple sclerosis (MS) that might result from functional disconnection in the frontocerebellar loop. Structural alterations in individual posterior lobules, in which cognitive functioning seems preponderant, are still unknown. Our aim was to investigate the impact of grey matter (GM) volume alterations in lobules VI to VIIIb on IPS in persons with clinically isolated syndrome (PwCIS), MS (PwMS) and healthy subjects (HS).

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Background: Depressive mood and other emotional symptoms are common in multiple sclerosis (MS). The patient-reported outcome version of the "Echelle d'Humeur Dépressive" (EHD-PRO) aims to differentiate between two dimensions of depressive mood in people living with MS (PwMS).

Objectives: First, to compare EHD-PRO assessment and its two dimensions, lack of emotional control and emotional blunting, between a large sample of healthy controls (HCs) and two samples of PwMS, relapsing-remitting MS (RRMS) and primary progressive MS (PPMS); and second, to analyse the relationships between EHD-PRO scores with neurological disability, cognitive function, fatigue and health-related quality of life (HR-QOL).

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Neuromyelitis optica (NMO) is a life-threatening disease without any validated treatment strategy. Recent retrospective studies suggested the efficacy of B cell depletion without any distinction between first-line or rescue therapy. To assess whether rituximab as first-line therapy in NMO could efficiently control the occurrence of relapses.

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Background: Patients with multiple sclerosis who have poor adherence to treatment have a higher risk of relapse than adherent patients. This study assessed adherence to, and effectiveness and convenience of, treatment with subcutaneous (sc) interferon (IFN) β-1a (Rebif®, Merck Serono SA) 44 or 22 μg three times weekly in patients with relapsing multiple sclerosis (RMS) using the RebiSmart® electronic, multidose, autoinjector for 1 year.

Study Design: European, multicentre, observational study among neurologists: inclusion criteria included RMS, Expanded Disability Status Scale score ≤ 6, sc IFN β-1a administered by RebiSmart for ≤ 6 weeks.

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Background: The independent prognostic value of cerebrospinal fluid analysis in multiple sclerosis is not established.

Objective: To determine the prognostic value of intrathecal synthesis in a cohort of patients with relapsing-onset MS taking into consideration demographic and imaging parameters.

Methods: In this prospective cohort study conducted from 1993 to 2013, we analyzed the time to confirmed disability (persistent above 6 months) and irreversible disability (persistent for the entire disease course) of two disability milestones, Expanded Disability Status Scale score ≥ 4 or 6, and the time to secondary progressive onset in 579 patients with relapsing-onset multiple sclerosis.

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Article Synopsis
  • Inherited white matter diseases, previously thought to mainly affect infants, are increasingly recognized in adults, prompting researchers to study their prevalence and diagnostic effectiveness in adults over 16 years old.
  • The study analyzed brain MRIs of 154 adult patients, finding distinct groups of leukoencephalopathies and achieving a diagnosis in 64% of cases.
  • Key findings included the identification of specific genetic disorders, such as CADASIL and EIF2B-related disorders, highlighting the value of systematic diagnostic approaches in adult-onset cases.
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The association between cognitive impairment, health-related quality of life (HRQoL) and vocational status has been studied in recent years in cross-sectional studies in multiple sclerosis (MS), but longitudinal data are still lacking. This study assesses this association in a sample of 65 newly diagnosed MS patients followed longitudinally. Each patient underwent a standardised clinical assessment, cognitive tests and the HRQoL SEP-59 questionnaire six months after the MS diagnosis (baseline) and seven years later (y7).

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