Meningiomas arise from arachnoidal cap cells of the meninges, constituting the most common type o... more Meningiomas arise from arachnoidal cap cells of the meninges, constituting the most common type of central nervous system tumors, and are considered benign tumors in most cases. Their incidence increases with age, and they mainly affect females, constituting 25-46% of primary spinal tumors. Spinal meningiomas could be detected incidentally or be unraveled by various neurological symptoms (e.g., back pain, sphincter dysfunction, sensorimotor deficits). The gold standard diagnostic modality for spinal meningiomas is Magnetic resonance imaging (MRI) which permits their classification into four categories based on their radiological appearance. According to the World Health Organization (WHO) classification, the majority of spinal meningiomas are grade 1. Nevertheless, they can be of higher grade (grades 2 and 3) with atypical or malignant histology and a more aggressive course. To date, surgery is the best treatment where the big majority of meningiomas can be cured. Advances in surgic...
Autoimmune brainstem encephalitis (BSE) is a rare neurological condition with a wide range of und... more Autoimmune brainstem encephalitis (BSE) is a rare neurological condition with a wide range of underlying etiologies. It can be subdivided into two broad groups: a primary inflammatory disease of the central nervous system (CNS) or a brainstem disorder secondary to systemic diseases where the CNS is only one of many affected organs. Symptoms range from mild to life-threatening manifestations. Most cases respond well to immunotherapy. Therefore, broad and in-depth knowledge of the various inflammatory disorders that target the brainstem is essential for guiding the diagnostic approach and assisting in early initiation of appropriate therapy. We herein report on a case of BSE and provide an overview of the various causes of autoimmune BSE with an emphasis on the clinical manifestations and diagnostic approach.
Following the great success of the first series of the Special Issue “Brain Stimulation and Neuro... more Following the great success of the first series of the Special Issue “Brain Stimulation and Neuroplasticity” [...]
BackgroundTarlov or perineural cysts are dilations of nerve roots resulting from a pathologically... more BackgroundTarlov or perineural cysts are dilations of nerve roots resulting from a pathologically increased cerebrospinal fluid pressure. Although it is very common in the general population, most of these cysts remain asymptomatic. In some cases, they can evolve and exert pressure on neural elements, independently from their initial size.Case reportIn this paper, we describe the case of a 33-year-old female known to have asymptomatic multiple and large radicular and pelvic Tarlov cysts. One cyst located in the right pelvic space progressed acutely after delivery, inducing a painful sciatica without neurological deficit. The intracystic bleeding can be a direct consequence of the delivery, leading to an acute and mechanical local compression of the right S1 root. A CT-guided puncture and aspiration allowed a complete recovery. This case report was completed by a review of the literature of these rare intracystic Tarlov bleedings.ConclusionsIntracystic hemorrhage is a rare complicati...
Fatigue is the most commonly reported symptom in patients with multiple sclerosis (MS). It is a w... more Fatigue is the most commonly reported symptom in patients with multiple sclerosis (MS). It is a worrisome, frequent, and debilitating manifestation that could occur at any time during the course of MS and in all its subtypes. It could engender professional, familial, and socioeconomic consequences and could severely compromise the patients' quality of life. Clinically, the symptom exhibits motor, cognitive, and psychosocial facets. It is also important to differentiate between perceived or subjective self-reported fatigue and fatigability which is an objective measure of decrement in the performance of cognitive or motor tasks. The pathophysiology of MS fatigue is complex, and its management remains a challenge, despite the existing body of literature on this matter. Hence, unraveling its neural mechanisms and developing treatment options that target the latter might constitute a promising field to explore. A PubMed/Medline/Scopus search was conducted to perform this review whic...
Electrical or magnetic stimulation methods for brain or nerve modulation have been widely known f... more Electrical or magnetic stimulation methods for brain or nerve modulation have been widely known for centuries, beginning with the Atlantic torpedo fish for the treatment of headaches in ancient Greece, followed by Luigi Galvani’s experiments with frog legs in baroque Italy, and leading to the interventional use of brain stimulation methods across Europe in the 19th century [...]
The objective of the different types of treatments for a spinal metastasis is to provide the best... more The objective of the different types of treatments for a spinal metastasis is to provide the best oncological and functional result with the least aggressive side effects. Initially created in 2010 to help clinicians in the management of vertebral metastases, the Spine Instability Neoplastic Score (SINS) has quickly found its place in the decision making and the treatment of patients with metastatic spinal disease. Here we conduct a review of the literature describing the different changes that occurred with the SINS score in the last ten years. After a brief presentation of the spinal metastases’ distribution, with or without spinal cord compression, we present the utility of SINS in the radiological diagnosis and extension of the disease, in addition to its limits, especially for scores ranging between 7 and 12. We take this opportunity to expose the latest advances in surgery and radiotherapy concerning spinal metastases, as well as in palliative care and pain control. We also di...
Annals of Clinical and Translational Neurology, 2021
We evaluated the effect of DMTs on Covid‐19 severity in patients with MS, with a pooled‐analysis ... more We evaluated the effect of DMTs on Covid‐19 severity in patients with MS, with a pooled‐analysis of two large cohorts from Italy and France. The association of baseline characteristics and DMTs with Covid‐19 severity was assessed by multivariate ordinal‐logistic models and pooled by a fixed‐effect meta‐analysis. 1066 patients with MS from Italy and 721 from France were included. In the multivariate model, anti‐CD20 therapies were significantly associated (OR = 2.05, 95%CI = 1.39–3.02, p < 0.001) with Covid‐19 severity, whereas interferon indicated a decreased risk (OR = 0.42, 95%CI = 0.18–0.99, p = 0.047). This pooled‐analysis confirms an increased risk of severe Covid‐19 in patients on anti‐CD20 therapies and supports the protective role of interferon.
Objectives: Alexithymia is a multicomponent personality construct that could occur in up to 53% o... more Objectives: Alexithymia is a multicomponent personality construct that could occur in up to 53% of patients with multiple sclerosis (MS), with recent works proposing higher rates of alexithymia in progressive MS. Among the available models of alexithymia, some propose a deficient interhemispheric communication and an aberrant GABAergic transmission at its origin. However, no single study has addressed the underlying mechanism of alexithymia in MS. The aim of this work was to assess the relationship between GABAergic neurotransmission and alexithymia in progressive MS by means of transcranial magnetic stimulation (TMS). Methods: Twelve patients with high alexithymia and fifteen patients with low alexithymia were included based on Toronto Alexithymia Scale (TAS). Sociodemographic, clinical and neuropsychological data were recorded. The following corticospinal excitability measures were obtained: resting motor threshold, cortical silent period (CSP which reflects cortical GABAergic function), and interhemispheric inhibition (i.e., GABAergic function mediated by interhemispheric fibers). Results: No significant group differences were observed regarding sociodemographic, clinical or neuropsychological variables. Patients with high alexithymia scores exhibited shorter CSP than those with low alexithymia scores (81.87 ± 45.72 ms vs. 145.27 ± 77.26 ms, respectively, p<0.05). A significant inverse correlation was also found between TAS scores and CSP duration (r=-0.59, p<0.05). Conclusion: This study offers insights into the neurophysiological mechanisms of alexithymia in MS. Reduced GABAergic transmission, as reflected by short CSP, seems to be associated with alexithymia in this population. Future studies would benefit from a more comprehensive evaluation of cortical and interhemispheric mechanisms in MS patients with alexithymia.
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. Distributed under a Creative Commons Attribution-NonCommercial| 4.0 International License
Journal of clinical neuroscience : official journal of the Neurosurgical Society of Australasia, 2018
Patients with multiple sclerosis (MS) commonly suffer from fatigue, a multidimensional symptom wi... more Patients with multiple sclerosis (MS) commonly suffer from fatigue, a multidimensional symptom with physical, cognitive and psychosocial components that can drastically alter the quality of life. Despite its debilitating nature, the current treatment options are limited by their modest efficacy and numerous side effects. Cognitive behavioral therapies (CBT) have been applied in MS patients and might be of help in relieving fatigue. This constitutes the main objective of the current review. Computerized databases (Medline/PubMed, Scopus) were consulted till January 2018, and a research was conducted according to PRISMA guidelines in order to identify original research articles published at any time in English and French languages on cognitive behavioral therapies and MS fatigue as a primary outcome. The following key terms were used: ('multiple sclerosis' OR 'MS') AND ('fatigue') AND ('cognitive behavioral therapy' OR 'CBT' OR 'cognitive th...
Tremor is frequently described in patients with multiple sclerosis (MS) but remains poorly charac... more Tremor is frequently described in patients with multiple sclerosis (MS) but remains poorly characterized using neurophysiological techniques. Accelerometric (ACC) and electromyographic (EMG) recordings were performed in 26 MS patients complaining of clumsiness, associated (n = 16) or not associated (n = 10) with visible tremor. Seventeen healthy subjects with physiological tremor (PT) and eight patients with essential tremor (ET) served as controls. Signals were analyzed using non-linear Empirical Mode Decomposition (EMD) and related Hilbert-Huang Transform (HHT), compared to the standard linear spectral analysis using Fast Fourier Transform (FFT). The presence of cerebellar signs and motor deficit was assessed on clinical examination. Using FFT, tremor was found in all patients with ET and 12% of subjects with PT, but in none of the MS patients, even in the presence of visible tremor. In contrast, EMD-HHT analysis of ACC-EMG coupling showed common frequency peaks characterizing tremor related to a central generator in 62.5% of MS patients with visible tremor, 40% of MS patients without visible tremor, 29% of subjects with PT, and all patients with ET. In EMD-HHT analysis, tremor characteristics were similar in subjects with PT and MS patients, regardless of the presence of a visible tremor, but these characteristics clearly differed in patients with ET. A visible tremor in MS patients was associated with more frequent cerebellar signs and less motor deficit at the upper limb. The low-frequency tremor observed in MS patients could therefore originate in lesions of the brainstem (midbrain) or cerebellothalamic circuits, or may correspond to an enhanced PT, partly favored by cerebellar dysfunction and being more visible during movement execution in the absence of concomitant motor deficit.
Fatigue is a frequent and debilitating symptom in patients with multiple sclerosis (MS). Its clas... more Fatigue is a frequent and debilitating symptom in patients with multiple sclerosis (MS). Its classical treatments are still faced with limited benefits and numerous side effects. Hence, we aimed to evaluate the effects of transcranial direct current stimulation (tDCS), a noninvasive brain stimulation technique, on such a challenging symptom. Our secondary outcomes included the assessment of tDCS impact on mood and attentional performance. Ten fatigued MS patients were enrolled in a double-blind, sham-controlled, and cross-over study. Each patient randomly received three anodal tDCS blocks: active stimulation over the left dorsolateral prefrontal cortex (DLPFC), active stimulation over the right posterior parietal cortex (PPC), and sham stimulation over either cortical site. Both cortical targets are key components in the MS fatigue networks. The blocks consisted of five consecutive daily sessions and were held apart by a washout interval of three weeks. Only active left DLPFC stimulation significantly ameliorated fatigue. Mood improvement was exclusively obtained following active right PPC stimulation. Neither intervention had effects on attention. Our study supports the role of anodal tDCS over the left prefrontal in treating MS fatigue. The lack of tDCS effects on attention might be related to the heterogeneity of the studied cohort, the relatively small sample size, the protocol design and duration. Modifying these variables and coupling tDCS with neuroimaging might improve the clinical outcomes and enhance our understanding of the tDCS mechanism of actions.
Le cortex cerebral est la cible qui a ete la plus recemment evaluee pour le traitement des douleu... more Le cortex cerebral est la cible qui a ete la plus recemment evaluee pour le traitement des douleurs neuropathiques par neuromodulation. Au debut des annees 1990, les premiers succes de la stimulation epidurale du cortex moteur implantee chirurgicalement (EMCS) ont ete publies. Quelques annees plus tard a ete developpee la stimulation magnetique transcrânienne repetitive (rTMS), une technique de stimulation non invasive. Puis la stimulation electrique transcrânienne a courant continu (tDCS) a ete proposee. Pour toutes ces approches de neuromodulation corticale, invasives ou non-invasives, la principale cible etudiee et validee a ete le cortex moteur (gyrus precentral), mais d’autres cibles corticales sont en cours d’evaluation, comme le cortex prefrontal dorsolateral. Les mecanismes d’action de ces techniques presentent certaines similitudes, en particulier entre l’EMCS et la rTMS, mais aussi des differences qui pourraient justifier des indications et des applications specifiques, en particulier entre la rTMS et la tDCS. Il est donc important de connaitre les principes de ces techniques et de realiser une evaluation rigoureuse des resultats obtenus, afin d’eviter tout effet de mode. Differents types de syndromes douloureux, notamment la douleur neuropathique chronique refractaire, peuvent etre significativement ameliores par l’implantation d’un stimulateur cortical (EMCS) ou la repetition de seances quotidiennes de rTMS a haute frequence (5 a 20 Hz) ou de tDCS anodique, notamment pour des douleurs lateralisees, si la stimulation est appliquee sur le cortex moteur controlateral a la douleur. Cependant, les strategies therapeutiques de stimulation corticale restent a optimiser, notamment sur le plan de la conception des electrodes de stimulation epidurale, le ciblage de la rTMS ou le montage des electrodes de tDCS. Ceci devrait permettre de reduire le taux encore eleve de patients non-repondeurs, qui ne beneficient pas d’effets cliniquement pertinents de l’application de ces techniques.
Background: Repetitive transcranial magnetic stimulation (rTMS) can relieve neuropathic pain when... more Background: Repetitive transcranial magnetic stimulation (rTMS) can relieve neuropathic pain when applied at high frequency (HF: 5-20 Hz) over the primary motor cortex (M1), contralateral to pain side. In most studies, rTMS is delivered over the hand motor hot spot (hMHS), whatever pain location. Navigation systems have been developed to guide rTMS targeting, but their value to improve rTMS efficacy remains to be demonstrated. Objective: To compare the analgesic efficacy of HF-rTMS targeting the hMHS (non-navigated procedure) or the M1 representation of the pain region (navigated procedure). Methods: The analgesic effect of a single session of 10 Hz-rTMS of M1 was assessed in 66 patients with neuropathic pain of various causes and locations, according to three conditions: sham or active non-navigated rTMS of the hMHS and active navigated rTMS of the pain region. Results: Pain was relieved by both active rTMS conditions, and not by sham. Pain location influenced the results: upper or lower limb pain was significantly relieved, but not facial or hemibody pain. Pain relief lasted 1 week only after navigated rTMS, compared to sham. Conclusion: Navigation may improve HF-rTMS efficacy in patients with limb pain, whereas targeting remains to be optimized for more diffuse or facial pain. What does this study add?: To produce analgesic effects, HF-rTMS should be applied over the precentral cortex contralaterally to the painful side. Although the hMHS is the target normally chosen for stimulation, the optimal target has not been defined yet. Neuronavigational methods have been recently developed; they allow the integration of MRI data and are thought to improve rTMS efficacy.
Aim of the study.-To characterize the motor command of the soft palate muscles using a magnetic s... more Aim of the study.-To characterize the motor command of the soft palate muscles using a magnetic stimulation technique. Material and methods.-Motor evoked potentials (MEPs) were recorded in 10 right-handed and 5 left-handed subjects at the midline of the palate or on the right or left hemipalate to peripheral and cortical magnetic stimulation. Results.-Mean palatal MEP amplitude ranged from 0.06 to 0.26 mV to peripheral stimulation and from 0.36 to 1.09 mV to cortical stimulation. In hemipalate recordings, MEPs to peripheral stimulation had greater amplitude when recorded ipsilaterally to the stimulation side, whereas MEPs to cortical stimulation were symmetrical. In midline recordings, right-handed subjects showed greater palatal MEP amplitude to right (rather than left) peripheral stimulation and to left (rather than right) cortical stimulation. Mean palatal MEP latency ranged from 4.0 to 4.1 ms to peripheral stimulation and from 9.0 to 10.2 ms to cortical stimulation; mean central conduction time ranged from 4.9 to 6.2 ms. Conclusion.-Palatal MEPs were easily and reliably obtained, including selective responses in each hemipalate. A bilateral cortical command of the palate is supported by our results, with a possible predominant motor drive from the left hemisphere in right-handed subjects.
Meningiomas arise from arachnoidal cap cells of the meninges, constituting the most common type o... more Meningiomas arise from arachnoidal cap cells of the meninges, constituting the most common type of central nervous system tumors, and are considered benign tumors in most cases. Their incidence increases with age, and they mainly affect females, constituting 25-46% of primary spinal tumors. Spinal meningiomas could be detected incidentally or be unraveled by various neurological symptoms (e.g., back pain, sphincter dysfunction, sensorimotor deficits). The gold standard diagnostic modality for spinal meningiomas is Magnetic resonance imaging (MRI) which permits their classification into four categories based on their radiological appearance. According to the World Health Organization (WHO) classification, the majority of spinal meningiomas are grade 1. Nevertheless, they can be of higher grade (grades 2 and 3) with atypical or malignant histology and a more aggressive course. To date, surgery is the best treatment where the big majority of meningiomas can be cured. Advances in surgic...
Autoimmune brainstem encephalitis (BSE) is a rare neurological condition with a wide range of und... more Autoimmune brainstem encephalitis (BSE) is a rare neurological condition with a wide range of underlying etiologies. It can be subdivided into two broad groups: a primary inflammatory disease of the central nervous system (CNS) or a brainstem disorder secondary to systemic diseases where the CNS is only one of many affected organs. Symptoms range from mild to life-threatening manifestations. Most cases respond well to immunotherapy. Therefore, broad and in-depth knowledge of the various inflammatory disorders that target the brainstem is essential for guiding the diagnostic approach and assisting in early initiation of appropriate therapy. We herein report on a case of BSE and provide an overview of the various causes of autoimmune BSE with an emphasis on the clinical manifestations and diagnostic approach.
Following the great success of the first series of the Special Issue “Brain Stimulation and Neuro... more Following the great success of the first series of the Special Issue “Brain Stimulation and Neuroplasticity” [...]
BackgroundTarlov or perineural cysts are dilations of nerve roots resulting from a pathologically... more BackgroundTarlov or perineural cysts are dilations of nerve roots resulting from a pathologically increased cerebrospinal fluid pressure. Although it is very common in the general population, most of these cysts remain asymptomatic. In some cases, they can evolve and exert pressure on neural elements, independently from their initial size.Case reportIn this paper, we describe the case of a 33-year-old female known to have asymptomatic multiple and large radicular and pelvic Tarlov cysts. One cyst located in the right pelvic space progressed acutely after delivery, inducing a painful sciatica without neurological deficit. The intracystic bleeding can be a direct consequence of the delivery, leading to an acute and mechanical local compression of the right S1 root. A CT-guided puncture and aspiration allowed a complete recovery. This case report was completed by a review of the literature of these rare intracystic Tarlov bleedings.ConclusionsIntracystic hemorrhage is a rare complicati...
Fatigue is the most commonly reported symptom in patients with multiple sclerosis (MS). It is a w... more Fatigue is the most commonly reported symptom in patients with multiple sclerosis (MS). It is a worrisome, frequent, and debilitating manifestation that could occur at any time during the course of MS and in all its subtypes. It could engender professional, familial, and socioeconomic consequences and could severely compromise the patients' quality of life. Clinically, the symptom exhibits motor, cognitive, and psychosocial facets. It is also important to differentiate between perceived or subjective self-reported fatigue and fatigability which is an objective measure of decrement in the performance of cognitive or motor tasks. The pathophysiology of MS fatigue is complex, and its management remains a challenge, despite the existing body of literature on this matter. Hence, unraveling its neural mechanisms and developing treatment options that target the latter might constitute a promising field to explore. A PubMed/Medline/Scopus search was conducted to perform this review whic...
Electrical or magnetic stimulation methods for brain or nerve modulation have been widely known f... more Electrical or magnetic stimulation methods for brain or nerve modulation have been widely known for centuries, beginning with the Atlantic torpedo fish for the treatment of headaches in ancient Greece, followed by Luigi Galvani’s experiments with frog legs in baroque Italy, and leading to the interventional use of brain stimulation methods across Europe in the 19th century [...]
The objective of the different types of treatments for a spinal metastasis is to provide the best... more The objective of the different types of treatments for a spinal metastasis is to provide the best oncological and functional result with the least aggressive side effects. Initially created in 2010 to help clinicians in the management of vertebral metastases, the Spine Instability Neoplastic Score (SINS) has quickly found its place in the decision making and the treatment of patients with metastatic spinal disease. Here we conduct a review of the literature describing the different changes that occurred with the SINS score in the last ten years. After a brief presentation of the spinal metastases’ distribution, with or without spinal cord compression, we present the utility of SINS in the radiological diagnosis and extension of the disease, in addition to its limits, especially for scores ranging between 7 and 12. We take this opportunity to expose the latest advances in surgery and radiotherapy concerning spinal metastases, as well as in palliative care and pain control. We also di...
Annals of Clinical and Translational Neurology, 2021
We evaluated the effect of DMTs on Covid‐19 severity in patients with MS, with a pooled‐analysis ... more We evaluated the effect of DMTs on Covid‐19 severity in patients with MS, with a pooled‐analysis of two large cohorts from Italy and France. The association of baseline characteristics and DMTs with Covid‐19 severity was assessed by multivariate ordinal‐logistic models and pooled by a fixed‐effect meta‐analysis. 1066 patients with MS from Italy and 721 from France were included. In the multivariate model, anti‐CD20 therapies were significantly associated (OR = 2.05, 95%CI = 1.39–3.02, p < 0.001) with Covid‐19 severity, whereas interferon indicated a decreased risk (OR = 0.42, 95%CI = 0.18–0.99, p = 0.047). This pooled‐analysis confirms an increased risk of severe Covid‐19 in patients on anti‐CD20 therapies and supports the protective role of interferon.
Objectives: Alexithymia is a multicomponent personality construct that could occur in up to 53% o... more Objectives: Alexithymia is a multicomponent personality construct that could occur in up to 53% of patients with multiple sclerosis (MS), with recent works proposing higher rates of alexithymia in progressive MS. Among the available models of alexithymia, some propose a deficient interhemispheric communication and an aberrant GABAergic transmission at its origin. However, no single study has addressed the underlying mechanism of alexithymia in MS. The aim of this work was to assess the relationship between GABAergic neurotransmission and alexithymia in progressive MS by means of transcranial magnetic stimulation (TMS). Methods: Twelve patients with high alexithymia and fifteen patients with low alexithymia were included based on Toronto Alexithymia Scale (TAS). Sociodemographic, clinical and neuropsychological data were recorded. The following corticospinal excitability measures were obtained: resting motor threshold, cortical silent period (CSP which reflects cortical GABAergic function), and interhemispheric inhibition (i.e., GABAergic function mediated by interhemispheric fibers). Results: No significant group differences were observed regarding sociodemographic, clinical or neuropsychological variables. Patients with high alexithymia scores exhibited shorter CSP than those with low alexithymia scores (81.87 ± 45.72 ms vs. 145.27 ± 77.26 ms, respectively, p<0.05). A significant inverse correlation was also found between TAS scores and CSP duration (r=-0.59, p<0.05). Conclusion: This study offers insights into the neurophysiological mechanisms of alexithymia in MS. Reduced GABAergic transmission, as reflected by short CSP, seems to be associated with alexithymia in this population. Future studies would benefit from a more comprehensive evaluation of cortical and interhemispheric mechanisms in MS patients with alexithymia.
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. Distributed under a Creative Commons Attribution-NonCommercial| 4.0 International License
Journal of clinical neuroscience : official journal of the Neurosurgical Society of Australasia, 2018
Patients with multiple sclerosis (MS) commonly suffer from fatigue, a multidimensional symptom wi... more Patients with multiple sclerosis (MS) commonly suffer from fatigue, a multidimensional symptom with physical, cognitive and psychosocial components that can drastically alter the quality of life. Despite its debilitating nature, the current treatment options are limited by their modest efficacy and numerous side effects. Cognitive behavioral therapies (CBT) have been applied in MS patients and might be of help in relieving fatigue. This constitutes the main objective of the current review. Computerized databases (Medline/PubMed, Scopus) were consulted till January 2018, and a research was conducted according to PRISMA guidelines in order to identify original research articles published at any time in English and French languages on cognitive behavioral therapies and MS fatigue as a primary outcome. The following key terms were used: ('multiple sclerosis' OR 'MS') AND ('fatigue') AND ('cognitive behavioral therapy' OR 'CBT' OR 'cognitive th...
Tremor is frequently described in patients with multiple sclerosis (MS) but remains poorly charac... more Tremor is frequently described in patients with multiple sclerosis (MS) but remains poorly characterized using neurophysiological techniques. Accelerometric (ACC) and electromyographic (EMG) recordings were performed in 26 MS patients complaining of clumsiness, associated (n = 16) or not associated (n = 10) with visible tremor. Seventeen healthy subjects with physiological tremor (PT) and eight patients with essential tremor (ET) served as controls. Signals were analyzed using non-linear Empirical Mode Decomposition (EMD) and related Hilbert-Huang Transform (HHT), compared to the standard linear spectral analysis using Fast Fourier Transform (FFT). The presence of cerebellar signs and motor deficit was assessed on clinical examination. Using FFT, tremor was found in all patients with ET and 12% of subjects with PT, but in none of the MS patients, even in the presence of visible tremor. In contrast, EMD-HHT analysis of ACC-EMG coupling showed common frequency peaks characterizing tremor related to a central generator in 62.5% of MS patients with visible tremor, 40% of MS patients without visible tremor, 29% of subjects with PT, and all patients with ET. In EMD-HHT analysis, tremor characteristics were similar in subjects with PT and MS patients, regardless of the presence of a visible tremor, but these characteristics clearly differed in patients with ET. A visible tremor in MS patients was associated with more frequent cerebellar signs and less motor deficit at the upper limb. The low-frequency tremor observed in MS patients could therefore originate in lesions of the brainstem (midbrain) or cerebellothalamic circuits, or may correspond to an enhanced PT, partly favored by cerebellar dysfunction and being more visible during movement execution in the absence of concomitant motor deficit.
Fatigue is a frequent and debilitating symptom in patients with multiple sclerosis (MS). Its clas... more Fatigue is a frequent and debilitating symptom in patients with multiple sclerosis (MS). Its classical treatments are still faced with limited benefits and numerous side effects. Hence, we aimed to evaluate the effects of transcranial direct current stimulation (tDCS), a noninvasive brain stimulation technique, on such a challenging symptom. Our secondary outcomes included the assessment of tDCS impact on mood and attentional performance. Ten fatigued MS patients were enrolled in a double-blind, sham-controlled, and cross-over study. Each patient randomly received three anodal tDCS blocks: active stimulation over the left dorsolateral prefrontal cortex (DLPFC), active stimulation over the right posterior parietal cortex (PPC), and sham stimulation over either cortical site. Both cortical targets are key components in the MS fatigue networks. The blocks consisted of five consecutive daily sessions and were held apart by a washout interval of three weeks. Only active left DLPFC stimulation significantly ameliorated fatigue. Mood improvement was exclusively obtained following active right PPC stimulation. Neither intervention had effects on attention. Our study supports the role of anodal tDCS over the left prefrontal in treating MS fatigue. The lack of tDCS effects on attention might be related to the heterogeneity of the studied cohort, the relatively small sample size, the protocol design and duration. Modifying these variables and coupling tDCS with neuroimaging might improve the clinical outcomes and enhance our understanding of the tDCS mechanism of actions.
Le cortex cerebral est la cible qui a ete la plus recemment evaluee pour le traitement des douleu... more Le cortex cerebral est la cible qui a ete la plus recemment evaluee pour le traitement des douleurs neuropathiques par neuromodulation. Au debut des annees 1990, les premiers succes de la stimulation epidurale du cortex moteur implantee chirurgicalement (EMCS) ont ete publies. Quelques annees plus tard a ete developpee la stimulation magnetique transcrânienne repetitive (rTMS), une technique de stimulation non invasive. Puis la stimulation electrique transcrânienne a courant continu (tDCS) a ete proposee. Pour toutes ces approches de neuromodulation corticale, invasives ou non-invasives, la principale cible etudiee et validee a ete le cortex moteur (gyrus precentral), mais d’autres cibles corticales sont en cours d’evaluation, comme le cortex prefrontal dorsolateral. Les mecanismes d’action de ces techniques presentent certaines similitudes, en particulier entre l’EMCS et la rTMS, mais aussi des differences qui pourraient justifier des indications et des applications specifiques, en particulier entre la rTMS et la tDCS. Il est donc important de connaitre les principes de ces techniques et de realiser une evaluation rigoureuse des resultats obtenus, afin d’eviter tout effet de mode. Differents types de syndromes douloureux, notamment la douleur neuropathique chronique refractaire, peuvent etre significativement ameliores par l’implantation d’un stimulateur cortical (EMCS) ou la repetition de seances quotidiennes de rTMS a haute frequence (5 a 20 Hz) ou de tDCS anodique, notamment pour des douleurs lateralisees, si la stimulation est appliquee sur le cortex moteur controlateral a la douleur. Cependant, les strategies therapeutiques de stimulation corticale restent a optimiser, notamment sur le plan de la conception des electrodes de stimulation epidurale, le ciblage de la rTMS ou le montage des electrodes de tDCS. Ceci devrait permettre de reduire le taux encore eleve de patients non-repondeurs, qui ne beneficient pas d’effets cliniquement pertinents de l’application de ces techniques.
Background: Repetitive transcranial magnetic stimulation (rTMS) can relieve neuropathic pain when... more Background: Repetitive transcranial magnetic stimulation (rTMS) can relieve neuropathic pain when applied at high frequency (HF: 5-20 Hz) over the primary motor cortex (M1), contralateral to pain side. In most studies, rTMS is delivered over the hand motor hot spot (hMHS), whatever pain location. Navigation systems have been developed to guide rTMS targeting, but their value to improve rTMS efficacy remains to be demonstrated. Objective: To compare the analgesic efficacy of HF-rTMS targeting the hMHS (non-navigated procedure) or the M1 representation of the pain region (navigated procedure). Methods: The analgesic effect of a single session of 10 Hz-rTMS of M1 was assessed in 66 patients with neuropathic pain of various causes and locations, according to three conditions: sham or active non-navigated rTMS of the hMHS and active navigated rTMS of the pain region. Results: Pain was relieved by both active rTMS conditions, and not by sham. Pain location influenced the results: upper or lower limb pain was significantly relieved, but not facial or hemibody pain. Pain relief lasted 1 week only after navigated rTMS, compared to sham. Conclusion: Navigation may improve HF-rTMS efficacy in patients with limb pain, whereas targeting remains to be optimized for more diffuse or facial pain. What does this study add?: To produce analgesic effects, HF-rTMS should be applied over the precentral cortex contralaterally to the painful side. Although the hMHS is the target normally chosen for stimulation, the optimal target has not been defined yet. Neuronavigational methods have been recently developed; they allow the integration of MRI data and are thought to improve rTMS efficacy.
Aim of the study.-To characterize the motor command of the soft palate muscles using a magnetic s... more Aim of the study.-To characterize the motor command of the soft palate muscles using a magnetic stimulation technique. Material and methods.-Motor evoked potentials (MEPs) were recorded in 10 right-handed and 5 left-handed subjects at the midline of the palate or on the right or left hemipalate to peripheral and cortical magnetic stimulation. Results.-Mean palatal MEP amplitude ranged from 0.06 to 0.26 mV to peripheral stimulation and from 0.36 to 1.09 mV to cortical stimulation. In hemipalate recordings, MEPs to peripheral stimulation had greater amplitude when recorded ipsilaterally to the stimulation side, whereas MEPs to cortical stimulation were symmetrical. In midline recordings, right-handed subjects showed greater palatal MEP amplitude to right (rather than left) peripheral stimulation and to left (rather than right) cortical stimulation. Mean palatal MEP latency ranged from 4.0 to 4.1 ms to peripheral stimulation and from 9.0 to 10.2 ms to cortical stimulation; mean central conduction time ranged from 4.9 to 6.2 ms. Conclusion.-Palatal MEPs were easily and reliably obtained, including selective responses in each hemipalate. A bilateral cortical command of the palate is supported by our results, with a possible predominant motor drive from the left hemisphere in right-handed subjects.
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Papers by Samar Ayache