Cortico-juxtacortical involvement increases risk of epileptic seizures in multiple sclerosis

Association Between Neurodegenerative Diseases and an Increased Risk of Epilepsy Based on Single Nucleotide Polymorphisms: A Mendelian Randomization Study

Epilepsy is a common neurological disorder characterized by transient brain dysfunction, attributed to a multitude of factors. The purpose of this study is to explore whether neurodegenerative diseases, specifically Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), and multiple sclerosis (MS), have a causal effect on epilepsy. Mendelian randomization (MR) methods were used to analyze the causal association between neurodegenerative diseases (AD, PD, ALS, and MS) and epilepsy based on single nucleotide polymorphisms from genome-wide association studies, including inverse-variance weighted, weighted median, MR-Egger, and weighted mode methods. The reliability and stability of the MR analysis results were assessed by the MR-Egger intercept, MR-PRESSO, and heterogeneity tests. Forty-three SNPs were selected for the MR analysis of MS and epilepsy. The inverse-variance weighted method showed a significant causal association between MS and increased risk of epilepsy (odds ratio 1.046; 95% confidence interval 1.001-1.093; P = 0.043). However, AD (P = 0.986), PD (P = 0.894), and ALS (P = 0.533) were not causally associated with epilepsy. Sensitivity analysis showed that the results were robust. The MR study confirmed the causal relationship between genetically predicted MS and epilepsy but did not support the causal relationship between genetically predicted AD, PD, and ALS on epilepsy.

Incidence and determinants of seizures in multiple sclerosis: a meta-analysis of randomised clinical trials

BACKGROUND

Seizures are reported to be more prevalent in individuals with multiple sclerosis (MS) compared with the general population. Existing data predominantly originate from population-based studies, which introduce variability in methodologies and are vulnerable to selection and reporting biases.

METHODS

This meta-analysis aims to assess the incidence of seizures in patients participating in randomised clinical trials and to identify potential contributing factors. Data were extracted from 60 articles published from 1993 to 2022. The pooled effect size, representing the incidence rate of seizure events, was estimated using a random-effect model. Metaregression was employed to explore factors influencing the pooled effect size.

RESULTS

The meta-analysis included data from 53 535 patients and 120 seizure events in a median follow-up of 2 years. The pooled incidence rate of seizures was 68.0 per 100 000 patient-years, significantly higher than the general population rate of 34.6. Generalised tonic-clonic seizures were the most common type reported, although there was a high risk of misclassification for focal seizures with secondary generalisation. Disease progression, longer disease duration, higher disability levels and lower brain volume were associated with a higher incidence of seizures. Particularly, sphingosine-1-phosphate receptor (S1PR) modulators exhibited a 2.45-fold increased risk of seizures compared with placebo or comparators, with a risk difference of 20.5 events per 100 000 patient-years.

CONCLUSIONS

Patients with MS face a nearly twofold higher seizure risk compared with the general population. This risk appears to be associated not only with disease burden but also with S1PR modulators. Our findings underscore epilepsy as a significant comorbidity in MS and emphasise the necessity for further research into its triggers, preventive measures and treatment strategies.

Clinical characteristics, course and prognosis of Multiple Sclerosis patients with epilepsy. A case control study: MS and epilepsy

BACKGROUND AND PURPOSE

Although more common than in the general population, seizures are an atypical manifestation of multiple sclerosis (MS) and their pathophysiology is not well understood. This study aims to examine the prevalence, clinical characteristics, brain imaging findings and course of epilepsy, presenting in patients with MS.

METHODS

Observational retrospective study of MS patients evaluated at a single MS reference center in Buenos Aires, Argentina, between 2011 and 2022, focusing on those who developed epilepsy (EMS). Clinical, demographic, and prognostic factors were evaluated and compared to a control group of non-epileptic MS patients (NEMS). To analyze specific epilepsy characteristics, a second control group of patients with non-lesional focal epilepsy (FNLE) was also included.

RESULTS

Twenty-five patients (18 women), were diagnosed with epilepsy, corresponding to a prevalence of 1.95%. Comparison of brain imaging characteristics between EMS and NEMS patients showed brain atrophy (32% vs 6.1%, p<0.01), as well as cortical (26% vs 4%, p=0.03) and juxtacortical lesions (84% vs 55%, p=0.05), were more frequent in EMS patients. However, after multivariate analysis, cortical atrophy was the only variable linked to a significant increase in risk of epilepsy (OR 24, 95%CI=2.3-200, p<0.01). No significant differences in clinical characteristics, disease activity, disability levels, response to disease modified treatment (DMT) or lack of DMT efficacy were observed between MS patients with or without epilepsy. Most patients received anti-seizure medication (ASM), and seizure control was better in EMS than in FNLE patients (92% vs 58%, p=0.022) with no differences found in drug resistance. We did not find predictors of seizure recurrence in the population studied.

CONCLUSION

We observed a lower prevalence of epilepsy in this group of MS patients, compared to other reported cohorts. Although epilepsy seems to have a benign course in MS patients, cortical atrophy appears to be an important contributor to the development of secondary epilepsy in MS patients. Further investigations will be necessary to identify risk factors or biomarkers predicting increased epilepsy risk in MS.

Epilepsy and demyelination: Towards a bidirectional relationship

Demyelination stands out as a prominent feature in individuals with specific types of epilepsy. Concurrently, individuals with demyelinating diseases, such as multiple sclerosis (MS) are at a greater risk of developing epilepsy compared to non-MS individuals. These bidirectional connections raise the question of whether both pathological conditions share common pathogenic mechanisms. This review focuses on the reciprocal relationship between epilepsy and demyelination diseases. We commence with an overview of the neurological basis of epilepsy and demyelination diseases, followed by an exploration of how our comprehension of these two disorders has evolved in tandem. Additionally, we discuss the potential pathogenic mechanisms contributing to the interactive relationship between these two diseases. A more nuanced understanding of the interplay between epilepsy and demyelination diseases has the potential to unveiling the molecular intricacies of their pathological relationships, paving the way for innovative directions in future clinical management and treatment strategies for these diseases.

Multiple sclerosis and seizures: A retrospective observational study in a multiple sclerosis autoimmunity center of excellence

PURPOSE

The prevalence of epilepsy in patients with multiple sclerosis (MS) is three to six times the prevalence in the general population. Mechanisms resulting in increased seizure risk are not fully understood. Our objective is to characterize patients with MS and epilepsy regarding timing of diagnoses, MS and seizure (SZ) type, EEG findings suggesting cortical dysfunction, frequency of status epilepticus (SE), and seizure freedom.

METHODS

This was a single center retrospective study. Cases were obtained via DataDirect via the University of Michigan electronic medical record from January 1, 2006 through October, 12, 2016. The University of Michigan Health System is a large academic institute with a tertiary referral center and an Autoimmunity Center of Excellence. Patients were included if chart listed one or more of the top 62 epilepsy, and one or more of the top 2 MS, most frequently entered ICD9 and ICD10 codes. Patients with alternative epilepsy etiology were excluded. 74 of 361 patients were included. We collected information regarding demographics, MS and SZ type, age at diagnosis, imaging, EEG, seizure freedom, medications, and SE.

RESULTS

We found a high percentage of patients with SE. Most patients with imaging had multiple lesions at seizure onset. 27/54 of patients with EEG data showed electrographic evidence of cortical dysfunction. 6/8 of EEGs in PPMS showed features consistent with cortical dysfunction, followed by 9/17 in SPMS and 11/23 in RRMS. 7/8 of patients with PPMS showed EEG evidence of temporal lobe dysfunction.

CONCLUSION

Time of seizure onset relative to MS diagnosis varied with MS type suggesting distinct pathophysiology. EEG results correspond with reports of increased cortical damage and temporal dysfunction in PPMS, but are unique as a functional modality (EEG) as indicator of gray matter dysfunction. EEG findings differed in RRMS and progressive MS suggesting possibility of supportive diagnostic marker. Our data suggests higher risk of SE in progressive MS and diminished rate of seizure freedom for MS patients with SE. We conclude that early treatment with antiseizure medication would be beneficial for MS patients with SE and with progressive MS forms and SZ, in agreement with previous studies.

Association between multiple sclerosis and epilepsy: A systematic review and meta-analysis

BACKGROUND

Seizures in people with multiple sclerosis (MS) are reported; however, the risk of epilepsy in adults with MS remains poorly defined.

METHODS

We performed a systematic review and meta-analysis to evaluate the incidence and prevalence of epilepsy in adults (≥ 18 years) with MS compared to those without. We searched MEDLINE and EMBASE from inception to July 1, 2022 to include observational studies that reported the prevalence or incidence of epilepsy in adults with MS and a comparator group, consisting of adults without MS or the general population. We used the Newcastle Ottawa Scale to evaluate quality of the included studies. We performed random-effects meta-analyses to determine the prevalence and incidence of epilepsy in adults with MS compared to the non-MS group.

RESULTS

We identified 17 studies consisting of 192,850 adults with MS, across nine countries. Most studies were of moderate quality as they did not specify the MS type or type of seizures. Compared to a comparison group, both the prevalence (pooled OR 2.04; 95% confidence interval 1.59-2.63, I² = 95.4, n = 12) and the incidence of epilepsy (pooled RR 3.34; 3.17-3.52, I² = 4.6%, n = 6) was higher in people with MS. Heterogeneity in estimates was not explained by additional analyses.

CONCLUSIONS

MS is an independent risk factor for both incident and prevalent epilepsy, suggesting variation in grey matter involvement over the disease course. Longitudinal studies are required to help identify patient and disease characteristics associated with epilepsy.

Multiple Sclerosis and Autoimmune Comorbidities

Multiple sclerosis (MS) is a chronic inflammatory and neurodegenerative disease of the central nervous system characterized by broad inter- and intraindividual heterogeneity and different prognoses. Multisystem comorbidities are frequent features in people with MS (PwMS) and can affect treatment choices, quality of life, disability and mortality. In this scenario, autoimmune comorbidities play a cardinal role for several reasons, such as the implication on MS pathogenesis, diagnostic delay, disease activity, disability progression, brain atrophy, and treatment choice. However, the impact of an autoimmune comorbid condition on MS is not fully elucidated. This review aims to summarize the currently available data on the incidence and prevalence of autoimmune diseases in PwMS, the possible effect of this association on clinical and neuroradiological MS course and its impact on treatment choice.

Temporal trends of epilepsy in multiple sclerosis

OBJECTIVES

Epilepsy is associated with advanced multiple sclerosis (MS). We aimed to investigate whether the incidence of epilepsy in MS has been affected by the introduction of disease-modifying treatments (DMT) for MS.

MATERIALS AND METHODS

This retrospective study included 14,557 patients from the Swedish MS register with MS onset between 1991 and 2018. Incident diagnoses of epilepsy or any seizure were identified through cross-linkage with the National Patient Register. Next, yearly prevalence of epilepsy as well as 5- and 10 years incidence of epilepsy or any seizure for consecutive years of MS onset were estimated, the latter with Kaplan-Meier analysis. Cox regression was used to adjust the association between the year of MS onset and incidence of epilepsy for baseline variables.

RESULTS

Prevalence of epilepsy in the MS cohort increased from 0.34% in 1991 to 2.54% in 2018 (yearly odds: 1.26 [1.22, 1.29]). The 5 years incidence rate of epilepsy, ranging from 0.4% (95% CI 0.008-0.79%) to 1.3% (95% CI 0.71-1.89%), and the 10 years incidence rate of epilepsy, ranging from 1.1% (95% CI 0.31-1.88%) to 2.6% (95% CI 1.22-3.97%) showed no significant trends (p = .147 and p = .418, respectively). Similarly, no significant trends were found for the incidences of any seizure. The incidence trends of epilepsy remained not significant after adjusting for sex, MS onset type (relapsing or progressive onset), or age at MS onset.

CONCLUSIONS

Our findings do not support the hypothesis that the introduction of novel DMT for MS has reduced the incidence of epilepsy among MS patients.

Seizures and epilepsy in multiple sclerosis, aquaporin 4 antibody-positive neuromyelitis optica spectrum disorder and myelin oligodendrocyte glycoprotein antibody-associated disease

Seizure is one of the manifestations of central nervous system (CNS) inflammatory demyelinating diseases, which mainly include multiple sclerosis (MS), aquaporin 4 antibody-positive neuromyelitis optica spectrum disorder (AQP4-NMOSD) and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD). "Acute symptomatic seizures secondary to MS / AQP4-NMOSD / MOGAD" occur in the acute phase of the diseases, and are more frequent in MOGAD. In contrast, recurrent non-provoked seizures, mainly attributed to "autoimmune-associated epilepsy", occur in the non-acute phase of the diseases. Seizures in MS / AQP4-NMOSD / MOGAD mostly have a focal-onset. MS patients with concomitant systemic infections, an earlier onset and a higher disease activity are more likely to have seizures, whereas factors such as higher MS severity, the presence of status epilepticus and cortical damage indicate a greater risk of developing epilepsy. In MOGAD, cerebral cortical encephalitis, acute disseminated encephalomyelitis (ADEM)-like phenotypes (predominately ADEM and multiphasic disseminated encephalomyelitis) indicate a higher seizure risk. Multiple relapses with ADEM-like phenotypes predict epilepsy in pediatrics with MOGAD. Pathophysiologically, acute symptomatic seizures in MS are associated with neuronal hyperexcitability secondary to inflammation and demyelination. Chronic epilepsy in MS is largely due to gliosis, neuronal dysfunction and synaptic abnormalities. The mainstay of treatment for seizures secondary to MS / AQP4-NMOSD / MOGAD include immunotherapy along with antiseizure medications. This critical review discusses the most-updated evidence on epidemiology, clinical correlates, and inflammatory mechanisms underlying seizures and epilepsy in MS / AQP4-NMOSD / MOGAD. Treatment cautions including drug-drug interactions and the impact of treatments on the other are outlined. We also highlight pitfalls and challenges in managing such patients and future research perspectives to address unsolved questions.

Severity of Epilepsy and Response to Antiseizure Medications in Individuals with Multiple Sclerosis: Analysis of a Real-World Dataset

Background and objectives:

Epilepsy is an important comorbidity that affects outcomes for people with multiple sclerosis (MS). However, it is unclear if seizure severity among individuals with coexistence of multiple sclerosis and epilepsy (MS+E) is higher than in those with other focal epilepsies. Our goal was to compare the overall severity of epilepsy in individuals with MS+E versus those with focal epilepsy without MS (E-MS) as defined by seizure-related healthcare utilization, frequency and duration of status epilepticus, and frequency of antiseizure medication (ASM) regimen changes.

Methods:

In this hypothesis-generating study, we analyzed a U.S. commercial nationwide de-identified claims dataset with > 86 million individuals between 1/1/2008 and 8/31/2019. Using validated algorithms, we identified adults with E-MS and those with MS+E. We compared the number and length of seizure-related hospital admissions, the number of claims and unique days with claims for status epilepticus, and the rates of ASM regimen changes between the MS+E and the E-MS groups.

Results:

During the study period, 66,708 individuals with E-MS and 537 with MS+E had ≥ 2 years of coverage after their initial diagnosis of epilepsy. There was no difference between the MS+E and E-MS groups in the percentage of individuals admitted for seizures and/or status epilepticus. However, MS+E with seizure-related admissions had more admissions and longer hospital stays than those with E-MS. MS+E who experienced status epilepticus had more unique days with status epilepticus claims compared to E-MS. MS+E were more likely to have ASM regimen changes in Year 2 after the initial diagnosis of epilepsy and had more ASM changes during Year 2 compared to E-MS. Among individuals with MS+E, there were no differences in our measures of seizure severity for those treated with sodium channel blockers/modulators versus other ASM classes.

Discussion:

This study supports the notion that individuals with MS+E can have more severe epilepsy than those with E-MS. Seizure severity among individuals with MS+E treated with sodium-channel blockers/modulators versus other ASM classes shows no significant differences.

Classification of evidence:

This study provides Class III evidence that individuals with MS+E can have more severe epilepsy than those with E-MS.

The Cross Talk between Underlying Mechanisms of Multiple Sclerosis and Epilepsy May Provide New Insights for More Efficient Therapies

Despite the significant differences in pathological background of neurodegenerative diseases, epileptic seizures are a comorbidity in many disorders such as Huntington disease (HD), Alzheimer's disease (AD), and multiple sclerosis (MS). Regarding the last one, specifically, it has been shown that the risk of developing epilepsy is three to six times higher in patients with MS compared to the general population. In this context, understanding the pathological processes underlying this connection will allow for the targeting of the common and shared pathological pathways involved in both conditions, which may provide a new avenue in the management of neurological disorders. This review provides an outlook of what is known so far about the bidirectional association between epilepsy and MS.

Prevalence of Seizure/Epilepsy in Patients with Multiple Sclerosis: A Systematic Review and Meta-Analysis

Background

Seizure and epilepsy are among the initial symptoms of multiple sclerosis (MS), yet different prevalence rates are reported for them in the previous studies. The goal of this systematic review is to estimate the pooled prevalence of seizure and epilepsy in patients with MS.

Methods

We searched PubMed, Scopus, EMBASE, Web of Science, google scholar, and gray literature including references from identified studies and conference abstracts published up to October 2019. The search strategy included the MeSH terms and text words as ((Epilepsies OR Seizure Disorder OR Seizure Disorders OR Awakening Epilepsy OR Epilepsy, Awakening OR Epilepsy, Cryptogenic OR Cryptogenic Epilepsies OR Cryptogenic Epilepsy OR Epilepsies, Cryptogenic OR epilepsy OR seizure) AND (Multiple Sclerosis OR Sclerosis, Multiple) OR Sclerosis, Disseminated) OR Disseminated Sclerosis) OR MS (Multiple Sclerosis)) OR Multiple Sclerosis, Acute Fulminating).

Results

The literature review resulted in 4860 articles; 2593 articles remained after eliminating the duplicates. For the final analysis, 39 articles were included, 9 of which were conference abstracts. The pooled prevalence of seizure in MS cases was 2%, 95% confidence interval (CI)(1%-3%) (I² = 91.8%, P < 0.001). The pooled prevalence of epilepsy in MS cases was 3%, 95% CI (2%-4%) (I2 = 92.9%, P < 0.001). The pooled prevalence of epilepsy in Asia, Europe, and America was 6%, 3%, and 3%, respectively. The level of heterogeneity decreased after subgroup analysis in Asian and American subgroups. Meta-regression analysis showed continent is not a source of heterogeneity (coefficient = -0.007, P = 0.6).

Conclusions

The result of this systematic review shows that the pooled prevalence of seizure and epilepsy among MS patients is 2% and 3%, respectively.

The prevalence of epileptic seizures in multiple sclerosis in a large tertiary hospital in Australia

Rationale

To determine the prevalence of epileptic seizures in multiple sclerosis (MS) at an Australian tertiary hospital and to define their clinical features.

Methods

We retrospectively analysed adult patients at the Royal Melbourne Hospital electronically identified to have ICD codes for MS and seizures and/or epilepsy between 1996 to 2019, utilising paper and electronic-based records.

Results

Of the 2,125 MS patients identified, 16 (0.75%) experienced epileptic seizures during a mean follow-up period of 12.9 years. Median age of MS diagnosis (SD) was 38 (9.3) years. Four patients had relapsing remitting MS (25%), 10 secondary progressive MS (63.5%), and 2 primary progressive MS (12.5%). More than two-thirds of patients had seizure onset following the diagnosis of MS, and the majority of these had advanced disease (approximate EDSS >6) at the time of seizure onset. Focal onset-seizures occurred in 87.5% of patients with seizures.

Conclusion

The estimated prevalence of seizures in our cohort was lower than in previous studies (0.75 vs 2-4%). In most cases, seizures occurred after the diagnosis of MS in the context of advanced disease. Further studies are required to determine if MS disease modifying treatments reduce the risk of seizures in this cohort.

Astrocyte Glutamate Uptake and Water Homeostasis Are Dysregulated in the Hippocampus of Multiple Sclerosis Patients With Seizures

While seizure disorders are more prevalent among multiple sclerosis (MS) patients than the population overall and prognosticate earlier death & disability, their etiology remains unclear. Translational data indicate perturbed expression of astrocytic molecules contributing to homeostatic neuronal excitability, including water channels (AQP4) and synaptic glutamate transporters (EAAT2), in a mouse model of MS with seizures (MS+S). However, astrocytes in MS+S have not been examined. To assess the translational relevance of astrocyte dysfunction observed in a mouse model of MS+S, demyelinated lesion burden, astrogliosis, and astrocytic biomarkers (AQP4/EAAT2/ connexin-CX43) were evaluated by immunohistochemistry in postmortem hippocampi from MS & MS+S donors. Lesion burden was comparable in MS & MS+S cohorts, but astrogliosis was elevated in MS+S CA1 with a concomitant decrease in EAAT2 signal intensity. AQP4 signal declined in MS+S CA1 & CA3 with a loss of perivascular AQP4 in CA1. CX43 expression was increased in CA3. Together, these data suggest that hippocampal astrocytes from MS+S patients display regional differences in expression of molecules associated with glutamate buffering and water homeostasis that could exacerbate neuronal hyperexcitability. Importantly, mislocalization of CA1 perivascular AQP4 seen in MS+S is analogous to epileptic hippocampi without a history of MS, suggesting convergent pathophysiology. Furthermore, as neuropathology was concentrated in MS+S CA1, future study is warranted to determine the pathophysiology driving regional differences in glial function in the context of seizures during demyelinating disease.

Subcortical lesions due to cobalamin deficiency: an unusual MRI lesion pattern

We present a 44-year-old male patient with new onset of right focal epilepsy and bilateral hand hypesthesia. Cerebral MRI showed bilateral T2w/DWI hyperintense subcortical lesions in the cingulate gyrus, insula, and amygdala, whereas spinal MRI revealed a cervical posterior column lesion, corresponding to subacute combined degeneration. Laboratory workup revealed a cobalamin deficiency due to type A gastritis, and no evidence of antibodies associated with limbic encephalitis. After sufficient cobalamin substitution, the cerebral and spinal lesions gradually regressed. Our case represents a unique cerebral subcortical MRI lesion pattern in a patient with epilepsy and cobalamin deficiency. Thus, the latter represents an important differential diagnosis for autoimmune encephalitis.

Management of seizures in patients with multiple sclerosis; an Iranian consensus

PURPOSE

Cooccurrence of a seizure in a patient with multiple sclerosis (MS) may complicate the management process. Questions, which may complicate the management process of a patient with MS and seizure, include "how should we approach to the patient", "how should we treat the patient", "how should we modify the patient's MS treatment strategy", etc. METHODS: We searched the electronic database PubMed on March 30, 2018 for articles in English that included the following search terms: "epilepsy" AND "multiple sclerosis" or "seizure" AND "multiple sclerosis" since 2013, to obtain the best recent relevant scientific evidence on the topic. A working group of 6 epilepsy and 5 MS experts took part in two consensus workshops in Tehran, Iran, in 2018. The final consensus manuscript was prepared and approved by all participants.

RESULTS

The search with words "seizure" and "multiple sclerosis" yielded 121 entries; 10 were relevant to the topic. The search with words "epilepsy" and "multiple sclerosis" yielded 400 entries; 7 were relevant to the topic. We reviewed these 17 articles and also some other references, derived from these articles or relevant to the topic, for the purpose of our review.

CONCLUSION

Cooccurrence of a seizure in a patient with MS may complicate the management process. In this review, we tried to provide answers to the frequently asked questions, considering the best available scientific evidence and expert opinion.

Patients With Epileptic Seizures and Multiple Sclerosis in a Multiple Sclerosis Center in Southern Germany Between 2003-2015

Background: So far, many studies have shown that the risk of developing seizures and epilepsy is higher among patients with multiple sclerosis (MS) than in the general population. However, the causal link between these two diseases is still unclear. In addition, it is not clearly understood whether and to what extent the manifestation of seizures and epilepsy in patients with MS affects the clinical course and the long-term prognosis of the disease. We aimed to retrospectively identify and describe patients with MS and with seizures and epilepsy which were seen at the Department of Neurology of the University of Regensburg in Germany between the years 2003-2015. Methods: With the help of the electronic documentation system of hospital admitted patients followed by scrutinizing medical records of patients with MS for evidence of seizures and epilepsy, we identified patients with MS and seizures or epilepsy. Results: We identified 22 individuals (1.74%) out of 1,267 patients with MS with seizures or epilepsy. 18 of these 22 individuals met criteria for epilepsy (1.42%). Nine MS patients (40.9%) suffered from relapsing-remitting MS (RRMS) whereas 11 MS patients (50.0%) showed a secondary progressive disease course (SPMS). Five of those (45.5%) converted from RRMS to SPMS before they acquired epilepsy. None of the identified patients with MS and seizures or epilepsy suffered from primary progressive MS (PPMS). Moreover, two MS patients (9.1%) had a history of seizures before MS onset. Seizures were of focal onset in 17 patients with MS (77.3%). Fourteen out of these 17 MS patients presented with focal to bilateral tonic-clonic seizures (82.4%). Five MS patients (22.7%) showed tonic clonic seizures of unknown onset. Status epilepticus was reported in three patients with MS (13%), for one patient the data was inconclusive. Conclusion: The occurrence of seizures and epilepsy was higher than in the general population, suggesting a causal relationship between both diseases. In most cases, seizures occurred after the first manifestation of MS. The high frequency of focal seizures supports the concept of cerebral lesions in patients with MS playing an important role in precipitation of seizures and epilepsy.

Epilepsy and associated mortality in patients with multiple sclerosis

BACKGROUND AND PURPOSE

We aimed to determine the prevalence of epilepsy in patients with multiple sclerosis (MS) at diagnosis, the risk of developing epilepsy after the diagnosis of MS and the relative risk of mortality associated with epilepsy.

METHODS

We used the UK Clinical Practice Research Data-link to identify 2526 patients with incident MS and 9980 age-, sex- and index year-matched non-MS controls from 1997 to 2006. Logistic regression was used to estimate odds ratios [95% confidence interval (CI)] for epilepsy and Cox regression was used to estimate hazard ratios (HRs) (95% CI) for epilepsy and mortality.

RESULTS

Patients with incident MS were on average 45 years old and 70.9% were female. At diagnosis, the prevalence of epilepsy in patients with MS was 1.30% compared with 0.57% in non-MS controls. At diagnosis, MS was associated with an adjusted odds ratio (95% CI) of 2.11 (1.36-3.27) for pre-existing epilepsy. Among epilepsy-free patients, the cumulative probabilities of developing epilepsy, first recorded within 10 years of the index date, were 2.77% for patients with MS and 0.90% for controls. MS was associated with an adjusted HR (95% CI) of 6.01 (2.94-12.29) for epilepsy. Among patients with MS, epilepsy was associated with an HR (95% CI) of 2.23 (1.02-4.84) for all-cause mortality.

CONCLUSIONS

This population-based study found an increased prevalence of epilepsy in patients with MS at diagnosis when compared with non-MS controls and the risk of developing epilepsy was also higher following the MS diagnosis. Patients with MS with epilepsy had a higher risk of mortality compared with those without.

A case of epilepsy in multiple sclerosis: Three-dimensional double inversion recovery sequences revealed cortical dysplasia

In epileptic patients with multiple sclerosis (MS), cortical lesions have been suggested to cause seizures. In brain magnetic resonance imaging (MRI), double inversion recovery (DIR) sequences are generally used to evaluate MS cortical disease burden. We present the case of a woman, diagnosed with MS, suffering from drug-resistant partial seizures initially attributed to MS. The patient underwent many MRI exams, but only by means of high-resolution three-dimensional DIR sequences was a focal cortical dysplasia discovered. The MRI findings and FDG-PET/CT supported the diagnosis. This case recommends the use of DIR sequences both in patients with suspect epileptogenic lesions not detected with routine MRI protocols and in epileptic patient with MS, before ascribing seizures to MS.

Chronic demyelination-induced seizures

Multiple sclerosis (MS) patients are three to six times more likely to develop epilepsy compared to the rest of the population. Seizures are more common in patients with early onset or progressive forms of the disease and prognosticate rapid progression to disability and death. Gray matter atrophy, hippocampal lesions, interneuron loss, and elevated juxtacortical lesion burden have been identified in MS patients with seizures; however, translational studies aimed at elucidating the pathophysiological processes underlying MS epileptogenesis are limited. Here, we report that cuprizone-mediated chronically demyelinated (9-12weeks) mice exhibit marked changes to dorsal hippocampal electroencephalography (EEG) and evidence of overt seizure activity. Immunohistochemical (IHC) analyses within the hippocampal CA1 region revealed extensive demyelination, loss of parvalbumin (PV⁺) interneurons, widespread gliosis, and changes in aquaporin-4 (AQP4) expression. Our results suggest that chronically demyelinated mice are a valuable model with which we may begin to understand the mechanisms underlying demyelination-induced seizures.

Temporal lobe cortical pathology and inhibitory GABA interneuron cell loss are associated with seizures in multiple sclerosis

BACKGROUND

Seizures are recognised in multiple sclerosis (MS), but their true incidence and the mechanism by which they are associated with MS is unclear.

OBJECTIVE

The objective of this paper is to determine the lifetime frequency of seizures in the United Kingdom MS Tissue Bank (UKMSTB) population and any pathological features associated with seizures.

METHODS

We evaluated 255 individuals from the UKMSTB. A subset underwent analysis of cortical thickness, grey matter lesion (GML) (type and number) and cortical neuronal numbers (total and GABAergic).

RESULTS

A total of 37/255 patients had seizures (14.5% lifetime incidence); in 47% they were associated with concurrent infection. In those with seizures, death and wheelchair use occurred earlier and in 59% seizures developed after 15 years of disease. Seizures were associated with Type 1 GMLs and reduced cortical thickness in the middle temporal gyrus. Localised selective GABAergic interneuron loss in layers IV and VI was related to GMLs but was not explained by the presence of inflammation or by mitochondrial dysfunction within Type I GMLs.

CONCLUSION

We confirm that seizure frequency rises in MS. Type I GMLs in the temporal lobe underlie a loss of inhibitory interneurons in cortical layers IV and VI and these changes could together with concurrent infection enhance susceptibility to seizures.

A systematic review of the incidence and prevalence of comorbidity in multiple sclerosis: overview

Background:

Comorbidity is an area of increasing interest in multiple sclerosis (MS).

Objective:

The objective of this review is to estimate the incidence and prevalence of comorbidity in people with MS and assess the quality of included studies.

Methods:

We searched the PubMed, SCOPUS, EMBASE and Web of Knowledge databases, conference proceedings, and reference lists of retrieved articles. Two reviewers independently screened abstracts. One reviewer abstracted data using a standardized form and the abstraction was verified by a second reviewer. We assessed study quality using a standardized approach. We quantitatively assessed population-based studies using the I² statistic, and conducted random-effects meta-analyses.

Results:

We included 249 articles. Study designs were variable with respect to source populations, case definitions, methods of ascertainment and approaches to reporting findings. Prevalence was reported more frequently than incidence; estimates for prevalence and incidence varied substantially for all conditions. Heterogeneity was high.

Conclusion:

This review highlights substantial gaps in the epidemiological knowledge of comorbidity in MS worldwide. Little is known about comorbidity in Central or South America, Asia or Africa. Findings in North America and Europe are inconsistent. Future studies should report age-, sex- and ethnicity-specific estimates of incidence and prevalence, and standardize findings to a common population.

A systematic review of the incidence and prevalence of sleep disorders and seizure disorders in multiple sclerosis

Background:

Several studies have suggested that comorbid neurologic disorders are more common than expected in multiple sclerosis (MS).

Objective:

To estimate the incidence and prevalence of comorbid seizure disorders and sleep disorders in persons with MS and to evaluate the quality of studies included.

Methods:

The PUBMED, EMBASE, Web of Knowledge, and SCOPUS databases, conference proceedings, and reference lists of retrieved articles were searched. Two reviewers independently screened abstracts to identify relevant articles, followed by full-text review of selected articles. We assessed included studies qualitatively and quantitatively (I² statistic), and conducted meta-analyses among population-based studies.

Results:

We reviewed 32 studies regarding seizure disorders. Among population-based studies the incidence of seizure disorders was 2.28% (95% CI: 1.11–3.44%), while the prevalence was 3.09% (95% CI: 2.01–4.16%). For sleep disorders we evaluated 18 studies; none were population-based. The prevalence ranged from 0–1.6% for narcolepsy, 14.4–57.5% for restless legs syndrome, 2.22–3.2% for REM behavior disorder, and 7.14–58.1% for obstructive sleep apnea.

Conclusion:

This review suggests that seizure disorders and sleep disorders are common in MS, but highlights gaps in the epidemiological knowledge of these conditions in MS worldwide. Other than central-western Europe and North America, most regions are understudied.

Multiple sclerosis and seizures: incidence and prevalence over 40 years

OBJECTIVES

The prevalence of multiple sclerosis (MS) is increasing worldwide. Epileptic seizures are more common in MS patients than in the general population. The aim of this study was to investigate changes in the prevalence and incidence of MS in a well-defined population over several decades and estimate the occurrence of epilepsy in the same cohort.

MATERIALS AND METHODS

Patients diagnosed with MS in the County of Vestfold, Norway in the period of 1983-2003 were identified. Point prevalence for MS and epilepsy was calculated for January 1, 2003. The average annual incidence rates were calculated in five-year periods from 1983 to 2002. These numbers were compared to previously published figures of prevalence from 1963 and incidence from 1953.

RESULTS

On prevalence day, we identified 364 patients diagnosed with MS living in Vestfold. Thus, the prevalence increased from 61.6/100,000 in 1963 to 166.8/100,000 in 2003. In the period 1983-2002, the annual incidence fluctuated between 4.2 and 7.3/100,000/year (mean 4.5, 95% CI 3.6 - 5.5). In 2003, the portion of MS patients with epileptic seizures was 7.4%, compared to 2.9% in 1963.

CONCLUSIONS

During the 40 years follow-up of this population, the incidence of MS was stable, while the prevalence of MS and the share of MS patients with epileptic seizures increased. Compared to the general population, the risk of having active epilepsy was increased fourfold. We assume that this is a consequence of an increased survival in MS patients.