Different pain phenotypes are associated with anti-Caspr2 autoantibodies

Autoantibodies against contactin-associated protein 2 (Caspr2) not only induce limbic autoimmune encephalitis but are also associated with pain conditions. Here, we analyzed clinical data on pain in a large cohort of patients included into the German Network for Research in Autoimmune Encephalitis. Out of 102 patients in our cohort, pain was a frequent symptom (36% of all patients), often severe (63.6% of the patients with pain) and/or even the major symptom (55.6% of the patients with pain). Pain phenotypes differed between patients. Cluster analysis revealed two major phenotypes including mostly distal-symmetric burning pain and widespread pain with myalgia and cramps. Almost all patients had IgG4 autoantibodies and some additional IgG1, 2, and/or 3 autoantibodies, but IgG subclasses, titers, and presence or absence of intrathecal synthesis were not associated with the occurrence of pain. However, certain pre-existing risk factors for chronic pain like diabetes mellitus, peripheral neuropathy, or preexisting chronic back pain tended to occur more frequently in patients with anti-Caspr2 autoantibodies and pain. Our data show that pain is a relevant symptom in patients with anti-Caspr2 autoantibodies and support the idea of decreased algesic thresholds leading to pain. Testing for anti-Caspr2 autoantibodies needs to be considered in patients with various pain phenotypes.

Amygdala and cortical gamma-band responses to emotional faces are modulated by attention to valence

The amygdala might support an attentional bias for emotional faces. However, whether and how selective attention toward a specific valence modulates this bias is not fully understood. Likewise, it is unclear whether amygdala and cortical signals respond to emotion and attention in a similar way. We recorded gamma-band activity (GBA, > 30 Hz) intracranially in the amygdalae of 11 patients with epilepsy and collected scalp recordings from 19 healthy participants. We presented angry, neutral, and happy faces randomly, and we denoted one valence as the target. Participants detected happy targets most quickly and accurately. In the amygdala, during attention to negative faces, low gamma-band activity (LGBA, < 90 Hz) increased for angry compared with happy faces from 160 ms. From 220 ms onward, amygdala high gamma-band activity (HGBA, > 90 Hz) was higher for angry and neutral faces than for happy ones. Monitoring neutral faces increased amygdala HGBA for emotions compared with neutral faces from 40 ms. Expressions were not differentiated in GBA while monitoring positive faces. On the scalp, only threat monitoring resulted in expression differentiation. Here, posterior LGBA was increased selectively for angry targets from 60 ms. The data show that GBA differentiation of emotional expressions is modulated by attention to valence: Top-down-controlled threat vigilance coordinates widespread GBA in favor of angry faces. Stimulus-driven emotion differentiation in amygdala GBA occurs during a neutral attentional focus. These findings align with a multi-pathway model of emotion processing and specify the role of GBA in this process.

Rehabilitation in patients with newly diagnosed epilepsy: A controlled, 1-year follow-up study on a specialized inpatient rehabilitation program

OBJECTIVES

To evaluate the efficacy of a specialized inpatient rehabilitation program in patients with newly diagnosed epilepsy (NDE), who had been referred within 1 year after diagnosis.

METHODS

We performed an open, prospective, controlled study comparing a 1-year follow-up assessment of patients with NDE after completing a rehabilitation program at an epilepsy center (rehabilitation group) with a control group of patients with similar epilepsy duration, but without rehabilitation in the first year after diagnosis. Primary outcome measures comprised emotional adaptation to epilepsy, depression and anxiety; and secondary outcome measures were overall quality of life (QoL), overall health, perceived restrictions because of epilepsy, level of information about epilepsy, and employment status.

RESULTS

Comparison of the admission data of 74 rehabilitation group patients (mean age and SD 47.7 ± 13.0 years) with the pre-rehabilitation assessment of 56 control patients (45.5 ± 12.1 years) revealed no significant differences concerning sociodemographic and health data. Comparison of the follow-up assessment of the rehabilitation group and the pre-rehabilitation assessment of the control group showed significantly better values for the rehabilitation group on emotional adaptation to epilepsy (p = .003), overall QoL (p = .006) and overall health (p = .011), perceived restrictions because of epilepsy, and subjective level of information about epilepsy (both p's < .001). There were no statistically significant differences concerning depression and anxiety or employment status (all p's > .50). One year after rehabilitation, patients in the rehabilitation group were more often seizure-free and less often on sickness absence than control group patients (both p's < .001).

SIGNIFICANCE

Since reduced QoL shortly after diagnosis of NDE is associated with seizure recurrence, an early identification of patients with a greater need for support seems important. This epilepsy-related rehabilitation program showed lasting effects on several aspects of adaptation to epilepsy and QoL.

Ethosuximide lowers lamotrigine serum concentrations: Evidence for a clinically relevant interaction

We investigated the effect of comedication with ethosuximide (ESM) on lamotrigine (LTG) blood levels. Based on observations from clinical practice, we hypothesized that ESM reduces the LTG serum concentration. We additionally evaluated this effect in the presence of concomitant valproic acid (VPA). We retrospectively analyzed samples of inpatients from our department who had been treated with a combination of ESM and LTG between 2017 and 2021. We additionally used data on LTG serum concentrations from a previously published cohort from our center. Generalized estimation equations (GEEs) were used for statistical analyses. We included 523 samples from 209 patients. GEE analyses showed that LTG trough serum concentrations were significantly lower in samples with ESM comedication and significantly higher in samples with concomitant VPA. The effect of ESM was moderated by patients' age; in children and adolescents, LTG serum concentrations were 37% lower than in samples without ESM, whereas in adults, LTG serum concentrations were 14% lower. The effect we found in our data is relevant to daily clinical practice, if patients are not seizure-free despite typical daily LTG dosage, or if they develop side effects during ESM withdrawal. It should be considered especially in children and adolescents.

Outcome of Epilepsy Surgery in MRI-Negative Patients Without Histopathologic Abnormalities in the Resected Tissue

BACKGROUND AND OBJECTIVE

Patients with presumed nonlesional focal epilepsy-based on either MRI or histopathologic findings-have a lower success rate of epilepsy surgery compared with lesional patients. In this study, we aimed to characterize a large group of patients with focal epilepsy who underwent epilepsy surgery despite a normal MRI and had no lesion on histopathology. Determinants of their postoperative seizure outcomes were further studied.

METHODS

We designed an observational multicenter cohort study of MRI-negative and histopathology-negative patients who were derived from the European Epilepsy Brain Bank and underwent epilepsy surgery between 2000 and 2012 in 34 epilepsy surgery centers within Europe. We collected data on clinical characteristics, presurgical assessment, including genetic testing, surgery characteristics, postoperative outcome, and treatment regimen.

RESULTS

Of the 217 included patients, 40% were seizure-free (Engel I) 2 years after surgery and one-third of patients remained seizure-free after 5 years. Temporal lobe surgery (adjusted odds ratio [AOR]: 2.62; 95% CI 1.19-5.76), shorter epilepsy duration (AOR for duration: 0.94; 95% CI 0.89-0.99), and completely normal histopathologic findings-versus nonspecific reactive gliosis-(AOR: 4.69; 95% CI 1.79-11.27) were significantly associated with favorable seizure outcome at 2 years after surgery. Of patients who underwent invasive monitoring, only 35% reached seizure freedom at 2 years. Patients with parietal lobe resections had lowest seizure freedom rates (12.5%). Among temporal lobe surgery patients, there was a trend toward favorable outcome if hippocampectomy was part of the resection strategy (OR: 2.94; 95% CI 0.98-8.80). Genetic testing was only sporadically performed.

DISCUSSION

This study shows that seizure freedom can be reached in 40% of nonlesional patients with both normal MRI and histopathology findings. In particular, nonlesional temporal lobe epilepsy should be regarded as a relatively favorable group, with almost half of patients achieving seizure freedom at 2 years after surgery-even more if the hippocampus is resected-compared with only 1 in 5 nonlesional patients who underwent extratemporal surgery. Patients with an electroclinically identified focus, who are nonlesional, will be a promising group for advanced molecular-genetic analysis of brain tissue specimens to identify new brain somatic epilepsy genes or epilepsy-associated molecular pathways.

Defining benchmark outcomes for mesial temporal lobe epilepsy surgery: A global multicenter analysis of 1119 cases

OBJECTIVE

Benchmarking has been proposed to reflect surgical quality and represents the highest standard reference values for desirable results. We sought to determine benchmark outcomes in patients after surgery for drug-resistant mesial temporal lobe epilepsy (MTLE).

METHODS

This retrospective multicenter study included patients who underwent MTLE surgery at 19 expert centers on five continents. Benchmarks were defined for 15 endpoints covering surgery and epilepsy outcome at discharge, 1 year after surgery, and the last available follow-up. Patients were risk-stratified by applying outcome-relevant comorbidities, and benchmarks were calculated for low-risk ("benchmark") cases. Respective measures were derived from the median value at each center, and the 75th percentile was considered the benchmark cutoff.

RESULTS

A total of 1119 patients with a mean age (range) of 36.7 (1-74) years and a male-to-female ratio of 1:1.1 were included. Most patients (59.2%) underwent anterior temporal lobe resection with amygdalohippocampectomy. The overall rate of complications or neurological deficits was 14.4%, with no in-hospital death. After risk stratification, 377 (33.7%) benchmark cases of 1119 patients were identified, representing 13.6%-72.9% of cases per center and leaving 742 patients in the high-risk cohort. Benchmark cutoffs for any complication, clinically apparent stroke, and reoperation rate at discharge were ≤24.6%, ≤.5%, and ≤3.9%, respectively. A favorable seizure outcome (defined as International League Against Epilepsy class I and II) was reached in 83.6% at 1 year and 79.0% at the last follow-up in benchmark cases, leading to benchmark cutoffs of ≥75.2% (1-year follow-up) and ≥69.5% (mean follow-up of 39.0 months).

SIGNIFICANCE

This study presents internationally applicable benchmark outcomes for the efficacy and safety of MTLE surgery. It may allow for comparison between centers, patient registries, and novel surgical and interventional techniques.

MRI evidence for material-specific encoding deficits and mesial-temporal alterations in presurgical frontal lobe epilepsy patients

OBJECTIVE

Neuroimaging studies reveal frontal lobe (FL) contributions to memory encoding. Accordingly, memory impairments are documented in frontal lobe epilepsy (FLE). Still, little is known about the structural or functional correlates of such impairments. Particularly, material specificity of functional changes in cerebral activity during memory encoding in FLE is unclear.

METHODS

We compared 24 FLE patients (15 right-sided) undergoing presurgical evaluation with 30 healthy controls on a memory fMRI-paradigm of learning scenes, faces, and words followed by an out-of-scanner recognition task as well as regarding their mesial temporal lobe (mTL) volumes. We also addressed effects of FLE lateralization and performance level (normal vs. low).

RESULTS

FLE patients had poorer memory performance and larger left hippocampal volumes than controls. Volume increase seemed, however, irrelevant or even dysfunctional for memory performance. Further, functional changes in FLE patients were right-sided for scenes and faces and bilateral for words. In detail, during face encoding, FLE patients had, regardless of their performance level, decreased mTL activation, while during scene and word encoding only low performing FLE patients had decreased mTL along with decreased FL activation. Intact verbal memory performance was associated with higher right frontal activation in FLE patients but not in controls.

SIGNIFICANCE

Pharmacoresistant FLE has a distinct functional and structural impact on the mTL. Effects vary with the encoded material and patients' performance levels. Thus, in addition to the direct effect of the FL, memory impairment in FLE is presumably to a large part due to functional mTL changes triggered by disrupted FL networks.

PLAIN LANGUAGE SUMMARY

Frontal lobe epilepsy (FLE) patients may suffer from memory impairment. Therefore, we asked patients to perform a memory task while their brain was scanned by MRI in order to investigate possible changes in brain activation during learning. FLE patients showed changes in brain activation during learning and also structural changes in the mesial temporal lobe, which is a brain region especially relevant for learning but not the origin of the seizures in FLE. We conclude that FLE leads to widespread changes that contribute to FLE patients' memory impairment.

German questionnaires assessing quality of life and psycho-social status in people with epilepsy: Reliable change and intercorrelations

OBJECTIVES

People with epilepsy (PWE) not only suffer from seizures but also from various psycho-social issues containing facets such as social functioning, anxiety, depression or stigmatization, and consequently quality of life. (1) Assessing reliable change of these issues is crucial to evaluate their course and potential treatment effects. As most psycho-social self-report questionnaires have been validated in separate samples, their clinical-socio-demographic differences may limit the comparability and generalizability of the scales' internal consistency, which is important for the reliable change index (RCI). Using a co-normalized approach, we provide the internal consistency and RCIs for a large set of questionnaires targeting quality of life (QOLIE-31-P), depressive symptoms (NDDI-E), anxiety (GAD-7), seizure severity (LSSS), subjective antiseizure medication adverse events (LAEP), stigma, epilepsy-related fear, and restrictions in daily life (PESOS), and subjective cognition (FLei). As for some German versions of these measures, psychometric data is still missing, we also add important information for the German language area. (2) In addition, knowledge about intercorrelations of these constructs is needed to shape questionnaire usage and treatment approaches. We thus investigate associations of these scales and compare weighted and unweighted subscales of the QOLIE-31-P.

METHODS

In our prospective study, 202 adult in-patients of the Epilepsy-Center Berlin-Brandenburg with a reliable diagnosis of epilepsy filled out a set of self-report questionnaires between 03/2018 and 03/2021. We calculated Cronbach's α, RCIs, and bivariate intercorrelations and compared the respective correlations of weighted and unweighted scales of the QOLIE-31-P.

RESULTS

For most of the scales, good to excellent internal consistency was identified. Furthermore, we found intercorrelations in the expected directions with strong links between scales assessing similar constructs (e.g., QOLIE-31-P Cognition and FLei), but weak relationships between measures for different constructs (e.g., QOLIE-31-P Seizure worry and FLei). The QOLIE-31-P Total score was highly correlated with most of the other scales. Some differences regarding their correlational patterns for weighted and unweighted QOLIE-31-P scales were identified.

CONCLUSIONS

Psycho-social constructs share a large amount of common variance, but still can be separated from each other. The QOLIE-31-P Total score represents an adequate measure of general psycho-social burden.

Glial Fibrillary Acidic Protein Autoimmunity After Aseptic Meningitis: A Report of 2 Cases

OBJECTIVES

We describe 2 patients with glial fibrillary acidic protein (GFAP) autoimmunity secondary to aseptic viral meningitis or meningoencephalomyelitis.

METHODS

This study involved a retrospective chart review.

RESULTS

Two female patients, 45 and 55 years of age, developed aseptic meningoencephalomyelitis or meningitis; in one patient, it was likely caused by herpes simplex virus 2. The patients were recovering from the infectious condition when they, 51 and 5 days after onset, had new symptoms with detection of GFAP antibodies in the CSF; CSF and serum samples from the initial lumbar punctures had been negative for GFAP antibodies. Both patients recovered with steroid treatment (in one case, plus rituximab; in the other, plus azathioprine) including resolution of MRI and CSF abnormalities.

DISCUSSION

These 2 patients had GFAP autoimmunity secondary to viral meningoencephalomyelitis or meningitis. This suggests that GFAP astrocytopathy might not always be a primary disease entity; it may follow another brain injury that triggers this autoimmune response.

Deep histopathology genotype-phenotype analysis of focal cortical dysplasia type II differentiates between the GATOR1-altered autophagocytic subtype IIa and MTOR-altered migration deficient subtype IIb

Focal cortical dysplasia type II (FCDII) is the most common cause of drug-resistant focal epilepsy in children. Herein, we performed a deep histopathology-based genotype-phenotype analysis to further elucidate the clinico-pathological and genetic presentation of FCDIIa compared to FCDIIb. Seventeen individuals with histopathologically confirmed diagnosis of FCD ILAE Type II and a pathogenic variant detected in brain derived DNA whole-exome sequencing or mTOR gene panel sequencing were included in this study. Clinical data were directly available from each contributing centre. Histopathological analyses were performed from formalin-fixed, paraffin-embedded tissue samples using haematoxylin-eosin and immunohistochemistry for NF-SMI32, NeuN, pS6, p62, and vimentin. Ten individuals carried loss-of-function variants in the GATOR1 complex encoding genes DEPDC5 (n = 7) and NPRL3 (n = 3), or gain-of-function variants in MTOR (n = 7). Whereas individuals with GATOR1 variants only presented with FCDIIa, i.e., lack of balloon cells, individuals with MTOR variants presented with both histopathology subtypes, FCDIIa and FCDIIb. Interestingly, 50% of GATOR1-positive cases showed a unique and predominantly vacuolizing phenotype with p62 immunofluorescent aggregates in autophagosomes. All cases with GATOR1 alterations had neurosurgery in the frontal lobe and the majority was confined to the cortical ribbon not affecting the white matter. This pattern was reflected by subtle or negative MRI findings in seven individuals with GATOR1 variants. Nonetheless, all individuals were seizure-free after surgery except four individuals carrying a DEPDC5 variant. We describe a yet underrecognized genotype-phenotype correlation of GATOR1 variants with FCDIIa in the frontal lobe. These lesions were histopathologically characterized by abnormally vacuolizing cells suggestive of an autophagy-altered phenotype. In contrast, individuals with FCDIIb and brain somatic MTOR variants showed larger lesions on MRI including the white matter, suggesting compromised neural cell migration.

What is autoimmune encephalitis-associated epilepsy? Proposal of a practical definition

Seizures resulting from cerebral autoimmunity are either acutely symptomatic in the context of autoimmune encephalitis (AIE) with neural surface antibodies, or they are indicative of an enduring predisposition to seizures, that is, epilepsy. Here, we propose a practical definition for autoimmune encephalitis-associated epilepsy (AEAE): Seizures associated with antibodies against glutamic acid decarboxylase, paraneoplastic syndromes, or Rasmussen encephalitis are classified as AEAE. AEAE secondary to AIE with antibodies against the N-methyl-D-aspartate receptor, leucine-rich glioma inactivated protein 1, contactin-associated protein-2, or γ-aminobutyric acid-B receptor can be diagnosed if the following criteria are met: seizures persist for at least 2 years after immunotherapy initiation; no signs of encephalitis on magnetic resonance imaging and no fluorodeoxyglucose positron emission tomography hypermetabolism; normal cerebrospinal fluid cell count; and a substantial decrease in antibody titers. This classification corresponds to different disease mechanisms. While AIE results from the pathogenic effects of neural antibodies, AEAE is probably the consequence of encephalitis-related tissue damage and thereby mainly structurally mediated. The distinction between AIE and AEAE also has practical consequences: In AIE, immunotherapy is usually highly beneficial, whereas anti-seizure medication has little effect. In AEAE, immunotherapy is less promising and the usual anti-seizure interventions are preferable. In addition, the diagnosis of AEAE has social consequences in terms of driving and professional limitations.

Assessment of self-stigma in epilepsy: Validation of the German version Epilepsy Self-Stigma Scale (ESSS-G)

OBJECTIVE

Self-stigma is the internalization of unfavorable public perceptions, which people with epilepsy (PWE) frequently experience. PWE with strong self-stigma have low self-esteem and are less likely to engage in treatment behavior. The Epilepsy Self-Stigma Scale (ESSS) has been developed and validated in Japan. We translated the ESSS into German for this study to examine its reliability and validity.

METHODS

We created the German version of ESSS (ESSS-G) based on the original Japanese version. From May to October 2022, we recruited out- and inpatients from Bethel Epilepsy Centre, University Hospital for Epileptology, for psychometric evaluation. Inclusion criteria were an age of ≥18 years, sufficient reading and speaking skills in German, and the ability to comprehend the German questionnaires. Participants also completed the Rosenberg Self-Esteem Scale (RSES), Neurological Disorders Depression Inventory for Epilepsy (NDDI-E), Generalized Anxiety Disorder 7 (GAD-7), Epilepsy Knowledge Scale, and items on "overall quality of life (QOL)" and "overall health" (items from QOLIE-31).

RESULTS

One hundred twenty-eight of 146 patients asked to participate granted informed consent and completed the study questionnaire (87.7% response rate). 115 cases were analyzed since 13 did not match the inclusion criteria. The analysis revealed a single factor explaining 49.2% of the total variance. All factor loadings were >0.40, and the reliability was high (Cronbach's α = 0.80). Higher ESSS total scores were associated with higher anxiety (GAD-7, r = 0.54, P < 0.001) and depression (NDDI-E, r = 0.45, P < 0.001), lower self-esteem (RSES, r = -0.41, P < 0.001), overall QOL (r = -0.40, P < 0.001), and overall health (r = -0.35, P < 0.001), but not with knowledge about epilepsy (r = 0.03, P = 0.770). In Germany, females, younger individuals, patients with earlier seizure onset, and those with generalized epilepsy had significantly higher self-stigma.

SIGNIFICANCE

The German version of the ESSS proved reliable and valid. It allows to evaluate the efficacy of treatment strategies in lowering self-stigma and conducting intercultural comparisons of epilepsy self-stigma.

Investigation of the presence of specific neural antibodies in dogs with epilepsy or dyskinesia using murine and human assays

BACKGROUND

Autoimmune mechanisms represent a novel category for causes of seizures and epilepsies in humans, and LGI1-antibody associated limbic encephalitis occurs in cats.

HYPOTHESIS/OBJECTIVES

To investigate the presence of neural antibodies in dogs with epilepsy or dyskinesia of unknown cause using human and murine assays modified for use in dogs.

ANIMALS

Fifty-eight dogs with epilepsy of unknown cause or suspected dyskinesia and 57 control dogs.

METHODS

Serum and CSF samples were collected prospectively as part of the diagnostic work-up. Clinical data including onset and seizure/episode type were retrieved from the medical records. Screening for neural antibodies was done with cell-based assays transfected with human genes for typical autoimmune encephalitis antigens and tissue-based immunofluorescence assays on mouse hippocampus slices in serum and CSF samples from affected dogs and controls. The commercial human und murine assays were modified with canine-specific secondary antibody. Positive controls were from human samples.

RESULTS

The commercial assays used in this study did not provide unequivocal evidence for presence of neural antibodies in dogs including one dog with histopathologically proven limbic encephalitis. Low titer IgLON5 antibodies were present in serum from one dog from the epilepsy/dyskinesia group and in one dog from the control group.

CONCLUSION AND CLINICAL IMPORTANCE

Specific neural antibodies were not detected using mouse and human target antigens in dogs with epilepsy and dyskinesia of unknown origin. These findings emphasize the need for canine-specific assays and the importance of control groups.

Hemispherotomy in Children: A Retrospective Analysis of 152 Surgeries in a Single Center and Predictors for Long-Term Seizure Outcome

OBJECTIVE

Completeness as a predictor of seizure freedom is broadly accepted in epilepsy surgery. We focused on the requirements for a complete hemispherotomy and hypothesized that the disconnection of the insula contributes to a favorable postoperative seizure outcome. We analyzed surgical and non-surgical predictors influencing long-term seizure outcome before and after a modification of our hemispherotomy technique.

METHODS

We retrospectively studied surgical procedures, electro-clinical parameters, MRI results, and follow-up data in all children who had undergone hemispherotomy between 2001 and 2018 at our institution. We used logistic regression models to analyze the influence of different factors on seizure outcome.

RESULTS

152 patients were eligible for seizure outcome analysis only. Of these, 140 cases had complete follow-up data for ≥24 months and provide the basis for the following results. The median age at surgery was 4.3 years (range 0.3-17.9 years). Complete disconnection (including the insular tissue) was achieved in 63.6% (89/140). At two-year follow-up, seizure freedom (Engel class IA) was observed in 34.8% (8/23) with incomplete insular disconnection while this was achieved in 88.8% (79/89) with complete surgical disconnection (p<0.001, OR=10.41). In the latter group (N=89), a potentially epileptogenic contralateral MRI lesion was the strongest predictor for postoperative seizure recurrence (OR=22.20).

SIGNIFICANCE

Complete surgical disconnection is the most important predictor of seizure freedom following hemispherotomy and requires disconnection of the insular tissue at the basal ganglia level. Even if the hemispherotomy is performed completely surgically, a potentially epileptogenic contralateral lesion on preoperative MRI significantly reduces the chances of postoperative seizure freedom.

Temporal lobe epilepsy with GAD antibodies: neurons killed by T cells not by complement membrane attack complex

Temporal lobe epilepsy (TLE) is one of the syndromes linked to antibodies against glutamic acid decarboxylase (GAD). It has been questioned whether 'limbic encephalitis with GAD antibodies' is a meaningful diagnostic entity. The immunopathogenesis of GAD-TLE has remained enigmatic. Improvement of immunological treatability is an urgent clinical concern. We retrospectively assessed the clinical, MRI and CSF course as well as brain tissue of 15 adult patients with GAD-TLE who underwent temporal lobe surgery. Brain tissue was studied by means of immunohistochemistry, multiplex fluorescent microscopy and transcriptomic analysis for inflammatory mediators and neuronal degeneration. In 10 patients, there was a period of mediotemporal swelling and T2 signal increase; in nine cases this occurred within the first 6 years after symptom onset. This resulted in unilateral or bilateral hippocampal sclerosis; three cases developed hippocampal sclerosis within the first 2 years. All CSF studies done within the first year (n = 6) revealed intrathecal synthesis of immunoglobulin G. Temporal lobe surgeries were done after a median disease duration of 9 years (range 3 weeks to 60 years). Only two patients became seizure-free. Brain parenchyma collected during surgery in the first 6 years revealed high numbers of plasma cells but no signs of antibody-mediated tissue damage. Even more dense was the infiltration by CD8+ cytotoxic T lymphocytes (CTLs) that were seen to locally proliferate. Further, a portion of these cells revealed an antigen-specific resident memory T cell phenotype. Finally, CTLs with cytotoxic granzyme B+ granules were also seen in microglial nodules and attached to neurons, suggesting a CTL-mediated destruction of these cells. With longer disease duration, the density of all lymphocytes decreased. Whole transcriptome analysis in early/active cases (but not in late/inactive stages) revealed 'T cell immunity' and 'Regulation of immune processes' as the largest overrepresented clusters. To a lesser extent, pathways associated with B cells and neuronal degeneration also showed increased representation. Surgically treated patients with GAD-TLE go through an early active inflammatory, 'encephalitic' stage (≤6 years) with CTL-mediated, antigen-driven neuronal loss and antibody-producing plasma cells but without signs of complement-mediated cell death. Subsequently, patients enter an apparently immunologically inactive or low-active stage with ongoing seizures, probably caused by the structural damage to the temporal lobe. 'Limbic encephalitis' with GAD antibodies should be subsumed under GAD-TLE. The early tissue damage explains why immunotherapy does not usually lead to freedom from seizures.

What neuropathology teaches us about autoimmune encephalitides, autoimmune epilepsies, and encephalomyelitides

Delineation of the autoimmune encephalitides with antibodies against neural surface antigens (anti-N-Methyl-D-aspartate, anti-leucine-rich glioma-inactivated protein 1, and others), autoimmune-associated epilepsies (Rasmussen encephalitis, paraneoplastic encephalitides, temporal lobe epilepsy with antibodies against glutamic acid decarboxylase), and encephalomyelitides with glial antibodies (neuromyelitis optica spectrum disorder, myelin oligodendrocyte glycoprotein antibody disease) has been a major advance in neurology. But how do these inflammatory diseases "work"? What kind of interaction between elements of the immune system and brain cells leads to these conditions? The only direct way of answering these questions is to investigate affected brain tissue by neuropathological techniques. They provide morphological and, in part, temporal information on the elements and localization of the disease process. Molecular techniques broaden and support these data. Brain tissue becomes available through autopsies and brain biopsies, obtained for diagnostic or therapeutic interventions. The limitations of neuropathological pathogenic research are discussed. Finally, representative neuropathological findings in autoimmune encephalitides and related conditions are summarized.

Ganglioglioma with adverse clinical outcome and atypical histopathological features were defined by alterations in PTPN11/KRAS/NF1 and other RAS-/MAP-Kinase pathway genes

Exome-wide sequencing studies recently described PTPN11 as a novel brain somatic epilepsy gene. In contrast, germline mutations of PTPN11 are known to cause Noonan syndrome, a multisystem disorder characterized by abnormal facial features, developmental delay, and sporadically, also brain tumors. Herein, we performed a deep phenotype-genotype analysis of a comprehensive series of ganglioglioma (GG) with brain somatic alterations of the PTPN11/KRAS/NF1 genes compared to GG with common MAP-Kinase signaling pathway alterations, i.e., BRAFV600E. Seventy-two GG were submitted to whole exome sequencing and genotyping and 84 low grade epilepsy associated tumors (LEAT) to DNA-methylation analysis. In 28 tumours, both analyses were available from the same sample. Clinical data were retrieved from hospital files including disease onset, age at surgery, brain localization, and seizure outcome. A comprehensive histopathology staining panel was available in all cases. We identified eight GG with PTPN11 alterations, copy number variant (CNV) gains of chromosome 12, and the commonality of additional CNV gains in NF1, KRAS, FGFR4 and RHEB, as well as BRAFV600E alterations. Histopathology revealed an atypical glio-neuronal phenotype with subarachnoidal tumor spread and large, pleomorphic, and multinuclear cellular features. Only three out of eight patients with GG and PTPN11/KRAS/NF1 alterations were free of disabling-seizures 2 years after surgery (38% had Engel I). This was remarkably different from our series of GG with only BRAFV600E mutations (85% had Engel I). Unsupervised cluster analysis of DNA methylation arrays separated these tumours from well-established LEAT categories. Our data point to a subgroup of GG with cellular atypia in glial and neuronal cell components, adverse postsurgical outcome, and genetically characterized by complex alterations in PTPN11 and other RAS-/MAP-Kinase and/or mTOR signaling pathways. These findings need prospective validation in clinical practice as they argue for an adaptation of the WHO grading system in developmental, glio-neuronal tumors associated with early onset focal epilepsy.

Hemodynamic correlates of emotion regulation in frontal lobe epilepsy patients and healthy participants

The ability to regulate emotions is indispensable for maintaining psychological health. It heavily relies on frontal lobe functions which are disrupted in frontal lobe epilepsy. Accordingly, emotional dysregulation and use of maladaptive emotion regulation strategies have been reported in frontal lobe epilepsy patients. Therefore, it is of clinical and scientific interest to investigate emotion regulation in frontal lobe epilepsy. We studied neural correlates of upregulating and downregulating emotions toward aversive pictures through reappraisal in 18 frontal lobe epilepsy patients and 17 healthy controls using functional magnetic resonance imaging. Patients tended to report more difficulties with impulse control than controls. On the neural level, patients had diminished activity during upregulation in distributed left-sided regions, including ventrolateral and dorsomedial prefrontal cortex, angular gyrus and anterior temporal gyrus. Patients also showed less activity than controls in the left precuneus for upregulation compared to downregulation. Unlike controls, they displayed no task-related activity changes in the left amygdala, whereas the right amygdala showed task-related modulations in both groups. Upregulation-related activity changes in the left inferior frontal gyrus, insula, orbitofrontal cortex, anterior and posterior cingulate cortex, and precuneus were correlated with questionnaire data on habitual emotion regulation. Our results show that structural or functional impairments in the frontal lobes disrupt neural mechanisms underlying emotion regulation through reappraisal throughout the brain, including posterior regions involved in semantic control. Findings on the amygdala as a major target of emotion regulation are in line with the view that specifically the left amygdala is connected with semantic processing networks.

How patients' psycho-social profiles contribute to decision-making in epilepsy surgery: A prospective study

OBJECTIVE

Identifying factors associated with surgical decision-making is important to understand reasons for underutilization of epilepsy surgery. Neurologists' recommendations for surgery and patients' acceptance of these recommendations depend on clinical epilepsy variables, for example, lateralization and localization of seizure onset zones. Moreover, previous research shows associations with demographic factors, for example, age and sex. Here, we investigate the relevance of patients' psycho-social profile for surgical decision-making.

METHODS

We prospectively studied 296 patients from two large German epilepsy centers. Multiple logistic regression analyses were used to investigate variables linked to neurologists' recommendations for and patients' acceptance of surgery or intracranial video-electroencephalographic monitoring. Patients' psycho-social profiles were assessed via self-reports and controlled for various clinical-demographic variables. Model selection was performed using the Akaike information criterion.

RESULTS

As expected, models for neurologists' surgery recommendations primarily revealed clinical factors such as lateralization and localization of the seizure onset zone, load with antiseizure medication (ASM), and site of the epilepsy-center. For this outcome, employment was the only relevant psycho-social aspect (odds ratio [OR] = .38, 95% confidence interval [CI] = .13-1.11). In contrast, three of the five relevant predictors for patients' acceptance were psycho-social. Higher odds were found for those with more subjective ASM adverse events (OR = 1.04, 95% CI = .99-1.00), more subjective seizure severity (OR = 1.12, 95% CI = 1.01-1.24), and lower subjective cognitive impairment (OR = .98, 95% CI = .96-1.00).

SIGNIFICANCE

We demonstrated the relevance of the patients' psycho-social profile for decision-making in epilepsy surgery, particularly for patients' decisions. Thus, in addition to clinical-demographic variables, patients' individual psycho-social characteristics add to the understanding of surgical decision-making. From a clinical perspective, this calls for individually tailored counseling to assist patients in finding the optimal treatment option.

Distinct movement disorders in contactin-associated-protein-like-2 antibody-associated autoimmune encephalitis

Autoimmune encephalitis can be classified into antibody-defined subtypes, which can manifest with immunotherapy-responsive movement disorders sometimes mimicking non-inflammatory aetiologies. In the elderly, anti-LGI1 and contactin associated protein like 2 (CASPR2) antibody-associated diseases compose a relevant fraction of autoimmune encephalitis. Patients with LGI1 autoantibodies are known to present with limbic encephalitis and additionally faciobrachial dystonic seizures may occur. However, the clinical spectrum of CASPR2 autoantibody-associated disorders is more diverse including limbic encephalitis, Morvan's syndrome, peripheral nerve hyperexcitability syndrome, ataxia, pain and sleep disorders. Reports on unusual, sometimes isolated and immunotherapy-responsive movement disorders in CASPR2 autoantibody-associated syndromes have caused substantial concern regarding necessity of autoantibody testing in patients with movement disorders. Therefore, we aimed to systematically assess their prevalence and manifestation in patients with CASPR2 autoimmunity. This international, retrospective cohort study included patients with CASPR2 autoimmunity from participating expert centres in Europe. Patients with ataxia and/or movement disorders were analysed in detail using questionnaires and video recordings. We recruited a comparator group with anti-LGI1 encephalitis from the GENERATE network. Characteristics were compared according to serostatus. We identified 164 patients with CASPR2 autoantibodies. Of these, 149 (90.8%) had only CASPR2 and 15 (9.1%) both CASPR2 and LGI1 autoantibodies. Compared to 105 patients with LGI1 encephalitis, patients with CASPR2 autoantibodies more often had movement disorders and/or ataxia (35.6 versus 3.8%; P < 0.001). This was evident in all subgroups: ataxia 22.6 versus 0.0%, myoclonus 14.6 versus 0.0%, tremor 11.0 versus 1.9%, or combinations thereof 9.8 versus 0.0% (all P < 0.001). The small group of patients double-positive for LGI1/CASPR2 autoantibodies (15/164) significantly more frequently had myoclonus, tremor, 'mixed movement disorders', Morvan's syndrome and underlying tumours. We observed distinct movement disorders in CASPR2 autoimmunity (14.6%): episodic ataxia (6.7%), paroxysmal orthostatic segmental myoclonus of the legs (3.7%) and continuous segmental spinal myoclonus (4.3%). These occurred together with further associated symptoms or signs suggestive of CASPR2 autoimmunity. However, 2/164 patients (1.2%) had isolated segmental spinal myoclonus. Movement disorders and ataxia are highly prevalent in CASPR2 autoimmunity. Paroxysmal orthostatic segmental myoclonus of the legs is a novel albeit rare manifestation. Further distinct movement disorders include isolated and combined segmental spinal myoclonus and autoimmune episodic ataxia.

Clinical Features, Neuropathology, and Surgical Outcome in Patients With Refractory Epilepsy and Brain Somatic Variants in the SLC35A2 Gene

BACKGROUND AND OBJECTIVES

The SLC35A2 gene, located at chromosome Xp11.23, encodes for a uridine diphosphate-galactose transporter. We describe clinical, genetic, neuroimaging, EEG, and histopathologic findings and assess possible predictors of postoperative seizure and cognitive outcome in 47 patients with refractory epilepsy and brain somatic SLC35A2 gene variants.

METHODS

This is a retrospective multicenter study where we performed a descriptive analysis and classical hypothesis testing. We included the variables of interest significantly associated with the outcomes in the generalized linear models.

RESULTS

Two main phenotypes were associated with brain somatic SLC35A2 variants: (1) early epileptic encephalopathy (EE, 39 patients) with epileptic spasms as the predominant seizure type and moderate to severe intellectual disability and (2) drug-resistant focal epilepsy (DR-FE, 8 patients) associated with normal/borderline cognitive function and specific neuropsychological deficits. Brain MRI was abnormal in all patients with EE and in 50% of those with DR-FE. Histopathology review identified mild malformation of cortical development with oligodendroglial hyperplasia in epilepsy in 44/47 patients and was inconclusive in 3. The 47 patients harbored 42 distinct mosaic SLC35A2 variants, including 14 (33.3%) missense, 13 (30.9%) frameshift, 10 (23.8%) nonsense, 4 (9.5%) in-frame deletions/duplications, and 1 (2.4%) splicing variant. Variant allele frequencies (VAFs) ranged from 1.4% to 52.6% (mean VAF: 17.3 ± 13.5). At last follow-up (35.5 ± 21.5 months), 30 patients (63.8%) were in Engel Class I, of which 26 (55.3%) were in Class IA. Cognitive performances remained unchanged in most patients after surgery. Regression analyses showed that the probability of achieving both Engel Class IA and Class I outcomes, adjusted by age at seizure onset, was lower when the duration of epilepsy increased and higher when postoperative EEG was normal or improved. Lower brain VAF was associated with improved postoperative cognitive outcome in the analysis of associations, but this finding was not confirmed in regression analyses.

DISCUSSION

Brain somatic SLC35A2 gene variants are associated with 2 main clinical phenotypes, EE and DR-FE, and a histopathologic diagnosis of MOGHE. Additional studies will be needed to delineate any possible correlation between specific genetic variants, mutational load in the epileptogenic tissue, and surgical outcomes.

GluN2B inhibition rescues impaired potentiation and epileptogenicity at associational-commissural CA3 synapses in a model of anti-NMDAR encephalitis

Anti-N-methyl-d-aspartate receptor (anti-NMDAR) encephalitis is an autoimmune epilepsy associated with memory deficits. Research has demonstrated that anti-NMDAR inhibit long-term potentiation, and, at the same time, lead to disinhibition in the form of epileptiform afterpotentials in the potentiated state. While both effects may give rise to the key symptoms of the disease, the molecular basis of being simultaneously inhibitory and disinhibitory is difficult to explain. Here, we explored a possible involvement of the GluN2B subunit. To this aim, we injected cerebrospinal fluid from anti-NMDAR encephalitis patients into the rat hippocampus and prepared brain slices for in vitro field potential recordings. Associational-commissural-fiber-CA3 synapses from anti-NMDAR-treated animals showed increased field potential amplitudes with concomitantly enhanced paired-pulse ratios as compared to control tissue. GluN2B inhibition by Ro25-6981 mimicked these effects in controls but had no effect in anti-NMDAR tissues indicating a presynaptic and occluding effect of anti-NMDAR. We then induced potentiation of associational-commissural-fiber-CA3 synapses, and confirmed that slices from anti-NMDAR-treated animals showed reduced potentiation and pronounced epileptiform afterpotentials. Intriguingly, both effects were absent when Ro25-6981 was added in vitro before inducing potentiation. These results indicate that GluN2B-containing NMDARs, partially expressed presynaptically, show differential sensitivity to anti-NMDAR, and that altered GluN2B function is particularly apparent in the potentiated state rather than under baseline conditions. Since GluN2B inhibition rescued the effects of anti-NMDAR in the potentiated state, this opens the possibility that at least a subgroup of patients could benefit from a GluN2B antagonist.

A retrospective non-interventional study evaluating the pharmacokinetic interactions between cenobamate and clobazam

Cenobamate is an antiseizure medication (ASM) approved for the treatment of partial-onset seizures in adults. As both an inductor and an inhibitor of hepatic enzymes, cenobamate affects the metabolism of other ASMs, among which is clobazam. To our knowledge, the extent of interaction between cenobamate and clobazam and its clinical significance have not been studied yet. In this retrospective study we assessed serum concentrations of clobazam and N-desmethylclobazam (NCLB)in five patients before and after co-medication with cenobamate and calculated the percentage increase in concentration-to-dose ratio (CDR) of both. We were able to demonstrate that the addition of cenobamate resulted in an increase in serum concentration and consequently in CDR of NCLB in all patients. However this occurred in variable degrees: NCLB concentration showed an increase of 1208 μg/L (CDR145%) in one patient and between 1691 μ/L (CDR 819%) and 3995 μ/L (CDR 1852%) in the other four. This resulted in fatigue, which improved after dose reduction of CLB. Therefore, it is to be concluded that concomitant administration of cenobamate and clobazam can lead to a substantial increase in serum concentrations of NCLB. This can have a positive therapeutic effect on one hand; however, on the other hand, this can lead to unwanted fatigue.

Have attitudes toward epilepsy improved in Germany over the last 50 years?

OBJECTIVE

In Germany, six previous representative surveys on attitudes toward epilepsy (AE) have been conducted between 1967 and 2008 using the four original Caveness questions (CQs) from 1949 to 1980. The aims of this study were (1) to investigate changes in AE over the time span of 50 years, including the current survey in 2018 (2) to investigate the first-time emotional reactions measured with the Scales of Attitudes toward People with Epilepsy (SAPE) (3) to identify predictors of AE.

METHODS

A representative face-to-face survey with CQ, in addition with the SAPE scales of Social Distance, Stereotypes, Personal Concerns, and Emotional Reactions was carried out in Germany in 2018. One thousand and twenty-six persons who ever had heard of epilepsy participated. Respondents who answered "don't know" in the CQs were subsequently asked to answer only yes/no. The analysis of trends from 1967 to 2018 was based on the pooled data of the surveys. The four CQs in the 2018 survey were included in the SAPE item pool and an exploratory principal axis factor analysis was performed. General linear models were performed to identify predictors.

RESULTS

For all four CQs, the trend of improved AE was significant over the past 50 years. In the 2018 survey, excluding the "don't know" answer option increased the proportion of negative responses for contact of one's own children with a person with epilepsy (PWE) from 6.9% to 11.4% and for the marriage of one's own children with a PWE from 13.9% to 23.8%. When encountering a PWE, 30.1% would feel insecure or uncomfortable and nearly 60% were concerned that the PWE might be injured in case of a seizure. Knowing what to do in case of a seizure, knowing that seizures can be treated successfully, personal contact with a PWE along with younger age, and higher education were found to be the strongest predictors for positive AE identified by multivariate analyses. Exploratory principal axis factor analysis revealed that three of the four CQs items loaded > 0.30 at the factors of Social Distance and Stereotypes of SAPE but none on the factors measuring emotional reactions.

SIGNIFICANCE

AE measured by CQs have markedly improved in Germany over the last 50 years. Germany is to our knowledge the only country with such a long-term trend investigation in AE. Negative AE may be underestimated by survey questions with "don't know" answer option. Emotional aspects of attitudes are underexposed resp. neglected in the CQs, which are used worldwide for measuring AE. Additional tools like SAPE can close this gap. The identified predictors may help to derive interventions against negative AE.

Efficacy of a specialized inpatient rehabilitation program in patients with early versus chronic epilepsy

OBJECTIVE

To evaluate the efficacy of a specialized inpatient rehabilitation program in patients with early in comparison with chronic epilepsy.

METHODS

We performed a prospective, open pre/post study using a parallel group design. Patients with early epilepsy (EE, treatment with anti-seizure medication [ASM] ≤ 1 year) or with chronic epilepsy (CE, ASM treatment > 5 years) completed questionnaires at the time of their admission to the rehabilitation program and at discharge. Outcome measures comprised scales from the PESOS questionnaire (PErformance, SOciodemographic aspects, Subjective estimation; e.g., emotional adaptation to epilepsy) as well as screening instruments for depression (Neurological Disorders Depression Inventory for Epilepsy, NDDI-E) and anxiety (Generalized Anxiety Disorder Scale, GAD-7). Linear mixed models (LMMs) were used to determine the effects of the program in the total group and to compare the effects between patients with EE and CE.

RESULTS

The analyses included 79 patients with EE and 157 patients with CE. Baseline comparisons revealed differences in disease-related and sociodemographic variables (e.g., patients with EE were older, those with CE had a higher seizure frequency and a higher rate of unemployment; all p < .01). LMMs showed significant improvements in emotional adaptation to epilepsy, depression, anxiety, overall quality of life and overall health as well as in perceived overall restrictions because of epilepsy and the subjective level of information about epilepsy (all p < .001). Despite the different duration of epilepsy, baseline levels as well as improvements did not differ between patients with EE and CE (all p > .05) except for the perceived level of information, which was significantly lower in patients with EE at admission and improved to a higher extent in this group (both p < .001).

CONCLUSION

Both patients with EE and patients with CE who are referred to a specialized comprehensive rehabilitation program benefit from the participation in this program with respect to emotional adaptation to epilepsy, aspects of quality of life, and level of information about epilepsy.

Seizure Semiology in Antibody-Associated Autoimmune Encephalitis

BACKGROUND AND OBJECTIVES

To assess seizure characteristics in antibody (ab)-associated autoimmune encephalitis (ab + AE) with the 3 most prevalent abs against N-methyl-d-aspartate receptor (NMDAR), leucine-rich glioma-inactivated protein 1 (LGI1), and glutamic acid decarboxylase (GAD).

METHODS

Multicenter nationwide prospective cohort study of the German Network for Research in Autoimmune Encephalitis.

RESULTS

Three hundred twenty patients with ab + AE were eligible for analysis: 190 NMDAR+, 89 LGI1+, and 41 GAD+. Seizures were present in 113 (60%) NMDAR+, 69 (78%) LGI1+, and 26 (65%) GAD+ patients and as leading symptoms for diagnosis in 53 (28%) NMDAR+, 47 (53%) LGI+, and 20 (49%) GAD+ patients. Bilateral tonic-clonic seizures occurred with almost equal frequency in NMDAR+ (38/51, 75%) and GAD+ (14/20, 70%) patients, while being less common in LGI1+ patients (27/59, 46%). Focal seizures occurred less frequently in NMDAR+ (67/113; 59%) than in LGI1+ (54/69, 78%) or in GAD+ patients (23/26; 88%). An aura with déjà-vu phenomenon was nearly specific in GAD+ patients (16/20, 80%). Faciobrachial dystonic seizures (FBDS) were uniquely observed in LGI1+ patients (17/59, 29%). Status epilepticus was reported in one-third of NMDAR+ patients, but only rarely in the 2 other groups. The occurrence of seizures was associated with higher disease severity only in NMDAR+ patients.

DISCUSSION

Seizures are a frequent and diagnostically relevant symptom of ab + AE. Whereas NMDAR+ patients had few localizing semiological features, semiology in LGI1+ and GAD+ patients pointed toward a predominant temporal seizure onset. FBDS are pathognomonic for LGI1 + AE. Status epilepticus seems to be more frequent in NMDAR + AE.

The genomic landscape across 474 surgically accessible epileptogenic human brain lesions

Understanding the exact molecular mechanisms involved in the etiology of epileptogenic pathologies with or without tumor activity is essential for improving treatment of drug-resistant focal epilepsy. Here, we characterize the landscape of somatic genetic variants in resected brain specimens from 474 individuals with drug-resistant focal epilepsy using deep whole-exome sequencing (>350×) and whole-genome genotyping. Across the exome, we observe a greater number of somatic single-nucleotide variants (SNV) in low-grade epilepsy-associated tumors (LEAT; 7.92 ± 5.65 SNV) than in brain tissue from malformations of cortical development (MCD; 6.11 ± 4 SNV) or hippocampal sclerosis (HS; 5.1 ± 3.04 SNV). Tumor tissues also had the largest number of likely pathogenic variant carrying cells. LEAT had the highest proportion of samples with one or more somatic copy number variants (CNV; 24.7%), followed by MCD (5.4%) and HS (4.1%). Recurring somatic whole chromosome duplications affecting Chromosome 7 (16.8%), chromosome 5 (10.9%), and chromosome 20 (9.9%) were observed among LEAT. For germline variant-associated MCD genes such as TSC2, DEPDC5, and PTEN, germline SNV were frequently identified within large loss of heterozygosity regions, supporting the recently proposed 'second hit' disease mechanism in these genes. We detect somatic variants in twelve established lesional epilepsy genes and demonstrate exome-wide statistical support for three of these in the etiology of LEAT (e.g., BRAF) and MCD (e.g., SLC35A2 and MTOR). We also identify novel significant associations for PTPN11 with LEAT and NRAS Q61 mutated protein with a complex MCD characterized by polymicrogyria and nodular heterotopia. The variants identified in NRAS are known from cancer studies to lead to hyperactivation of NRAS, which can be targeted pharmacologically. We identify large recurrent 1q21-q44 duplication including AKT3 in association with focal cortical dysplasia type 2a with hyaline astrocytic inclusions, another rare and possibly under-recognized brain lesion. The clinical genetic analyses showed that the numbers of somatic SNV across the exome and the fraction of affected cells were positively correlated with the age at seizure onset and surgery in individuals with LEAT. In summary, our comprehensive genetic screen sheds light on the genome-scale landscape of genetic variants in epileptic brain lesions, informs the design of gene panels for clinical diagnostic screening, and guides future directions for clinical implementation of epilepsy surgery genetics.

Distinct interacting cortical networks for stimulus-response and repetition-suppression

Non-invasive studies consider the initial neural stimulus response (SR) and repetition suppression (RS) - the decreased response to repeated sensory stimuli - as engaging the same neurons. That is, RS is a suppression of the SR. We challenge this conjecture using electrocorticographic (ECoG) recordings with high spatial resolution in ten patients listening to task-irrelevant trains of auditory stimuli. SR and RS were indexed by high-frequency activity (HFA) across temporal, parietal, and frontal cortices. HFASR and HFARS were temporally and spatially distinct, with HFARS emerging later than HFASR and showing only a limited spatial intersection with HFASR: most HFASR sites did not demonstrate HFARS, and HFARS was found where no HFASR could be recorded. β activity was enhanced in HFARS compared to HFASR cortical sites. θ activity was enhanced in HFASR compared to HFARS sites. Furthermore, HFASR sites propagated information to HFARS sites via transient θ:β phase-phase coupling. In contrast to predictive coding (PC) accounts our results indicate that HFASR and HFARS are functionally linked but have minimal spatial overlap. HFASR might enable stable and rapid perception of environmental stimuli across extended temporal intervals. In contrast HFARS might support efficient generation of an internal model based on stimulus history.

Face processing and efficient recognition of facial expressions are impaired following right but not left anteromedial temporal lobe resections: Behavioral and fMRI evidence

Anteromedial temporal lobe structures seem to support processing of faces and facial expressions. However, differential effects of unilateral left or right temporal lobe resections (TLR) on face processing, recognition of facial expressions, and on BOLD response to faces in intact brain areas are not yet fully understood. Therefore, we compared 39 patients with unilateral TLR (18 left, 21 right) and 20 healthy controls regarding recognition of facial identity and emotional facial expressions as well as BOLD response to fearful and neutral faces. We found impaired recognition of facial identity following right TLR, which was paralleled by reduced BOLD response to faces irrespective of expression in the right fusiform and lingual gyrus in postsurgical fMRI. Right TLR patients also exhibited subtle impairments of emotion recognition as they needed higher intensity of facial expressions for correct responses in a morphing task. Accuracy of emotion recognition and subjective appraisals of facial expressions did not differ between groups. There was no specific reduction of BOLD response to fearful versus neutral faces in either patient group. Our results underline the specific role of the right anteromedial temporal lobe in processing of faces and facial expressions by showing changes in face processing following right TLR in behavioral as well as imaging data.

Emotion and attention in face processing: Complementary evidence from surface event-related potentials and intracranial amygdala recordings

Face processing is biased by emotional and voluntarily directed attention, both of which modulate processing in distributed cortical areas. The amygdala is assumed to contribute to an attentional bias for emotional faces, although its interaction with directed attention awaits further clarification. Here, we studied the interaction of emotion and attention during face processing via scalp EEG potentials of healthy participants and intracranial EEG (iEEG) recordings of the right amygdala in one patient. Three randomized blocks consisting of angry, neutral, and happy facial expressions were presented, and one expression was denoted as the target category in each block. Happy targets were detected fastest and most accurately both in the group study and by the iEEG patient. Occipital scalp potentials revealed emotion differentiation for happy faces in the early posterior negativity (EPN) around 300 ms after stimulus onset regardless of the target condition. A similar response to happy faces occurred in the amygdala only for happy targets. On the scalp, a late positive potential (LPP, around 600 ms) enhancement for targets occurred for all target conditions alike. A simultaneous late signal in the amygdala was largest for emotional targets. No late signal enhancements were found for neutral targets in the amygdala. Cortical modulations, by contrast, showed both attention-independent effects of emotion and emotion-independent effects of attention. These results demonstrate an attention-dependence of amygdala activity during the processing of facial expressions and partly independent cortical mechanisms.

Case Report: Anti-GABAA Receptor Encephalitis in a Dog

Autoantibodies against neurotransmitter receptors detected in cerebrospinal fluid (CSF) and serum are increasingly recognized in people with human autoimmune encephalitis causing severe neurological deficits, such as seizures and behavioral abnormalities. This case report describes the first encephalitis associated with antibodies against the γ-aminobutyric acid-A receptor (GABA_AR) in a dog. A young male intact Cavalier King Charles Spaniel was presented with recent onset of initial multiple generalized tonic-clonic seizures progressing into a status epilepticus. Interictally, he showed alternating stupor and hyperexcitability, ataxia, pleurothotonus and circling behavior to the left side. Magnetic resonance imaging (MRI) of the brain showed breed-specific anatomical abnormalities. Standard CSF analysis was unremarkable. Despite treatment with multiple antiseizure medications (ASMs) seizures and behavior abnormalities sustained. Immunotherapy with dexamethasone was started on the fifth day after disease manifestation. This led to rapid improvement of clinical signs. An extensive antibody search in CSF and serum demonstrated a neuropil staining pattern on a tissue-based assay compatible with GABA_AR antibodies. The diagnosis was confirmed by binding of serum and CSF antibodies to GABA_AR transfected Human Embryonic Kidney cells. The serum titer was 1:320, the CSF titer 1:2. At the control visit 4.5 weeks after start of immunotherapy, the dog was clinically normal. The GABA_AR antibody titer in serum had strongly decreased. The antibodies were no longer detectable in CSF. Based on clinical presentation and testing for GABA_AR binding antibodies, this describes the first veterinary patient with an anti-GABA_AR encephalitis with a good outcome following ASM and corticosteroid treatment.

Attitudes toward epilepsy assessed by the SAPE questionnaire in Germany - Comparison of its psychometric properties and results in a web-based vs. face-to-face survey

OBJECTIVE

The aims of this study were (1) to investigate psychometric properties of a new questionnaire (SAPE, Scales of the Attitudes toward People with Epilepsy) that assesses attitudes toward people with epilepsy (PWE) (2) to compare the effects of mode of survey administration (web-based vs. face-to-face) on attitudes, and (3) to identify predictors of attitudes.

METHODS

A face-to-face and a web-based survey were performed in Germany. Weighting factors were used to achieve representative samples of the German population. Reliability and validity of the 6 scales of the SAPE (social distance, stereotypes, personal concerns, and emotional reactions differentiated by fear, anger, and pity) were evaluated and compared for both surveys. Epilepsy knowledge was also assessed. General linear models were performed to investigate predictors of attitudes toward PWE including the type of survey.

RESULTS

In total, 1001 participants of the web-based survey and 1026 participants of face-to-face survey were included. Psychometric analyses indicated satisfactory reliability and validity of the scales and differed only slightly between modes of survey. In both surveys, fears and concerns were more pronounced than stereotypes and social distance. However, mean values of two scales were slightly or moderately higher in the face-to-face survey indicating more negative attitudes toward PWE (p < 0.001). Fewer participants of the face-to-face survey reported personal experience with PWE, claiming to know what to do in case of a seizure and claiming to know that seizures can be treated successfully (p < 0.001). These variables proved to be important predictors of positive attitudes toward PWE, besides demographic factors (e.g. age < 65, female gender). When controlling for them, the differences remained significant only for the scales Social Distance (moderately) and Fear (slightly).

SIGNIFICANCE

In total, psychometric analyses show that web-based surveys using the SAPE may be an alternative to face-to-face surveys to assess attitudes toward PWE. This applies also to the scales Social Distance and Emotional Reactions that allow comparisons with other diseases, e.g. psychiatric disorders. Most scales differ only slightly between survey modes, except social distance. This indicates that single components of attitudes toward PWE may be dependent on the mode of survey or different characteristics of respondents.

Epilepsy Surgery in Extratemporal vs Temporal Lobe Epilepsy: Changes in Surgical Volumes and Seizure Outcome Between 1990 and 2017

Objective:

Seizure outcome after extratemporal lobe epilepsy (exTLE) surgery has often been poorer than after temporal lobe epilepsy (TLE) surgery, but recent improvements in diagnostics and surgery may have changed this. Our aim was to analyze the changes in presurgical and surgical volumes and seizure outcome two years after surgery for patients with exTLE compared to those with TLE.

Methods:

We performed a retrospective, single-center cohort study including patients from the Bethel presurgical-surgical-postsurgical database from 1990 to 2017. We used logistic regression to analyze factors influencing the odds for surgery and the odds for seizure freedom after surgery.

Results:

We included 3822 patients with presurgical evaluation, 2404 of whom had subsequently undergone surgery. The proportion of exTLE patients in presurgical evaluation increased from 41% between 1990-1993 to 64% in 2014-2017. The odds for surgery decreased over time (2003-2011: OR=0.50 [95%CI 0.36-0.70]; 2012-2017: OR=0.24 [CI 0.17-0.35]; reference: 1990-2002), and patients with exTLE had lower odds for surgery than TLE patients, but this difference diminished over time (exTLE vs. TLE 1990-2002: OR=0.14 [CI 0.09-0.20]; 2003-2011: OR=0.32 [CI 0.24-0.44]; 2012-2017: OR=0.46 [CI 0.34-0.63]). Etiology, the side of the epileptogenic lesion and invasive recordings additionally influenced the odds for surgery. The most frequent reasons for not undergoing surgery were the missing identification of a circumscribed epileptogenic zone or an unacceptable risk of postsurgical deficits in exTLE patients and the patient’s decision in TLE patients. Compared to TLE patients, the odds for seizure freedom after surgery started lower for patients with exTLE in earlier years, but increased (≤2 lobes 1990-2002: OR=0.47 [CI 0.33-0.68]; 2003-2011: OR=0.62 [CI 0.44-0.87]; 2012-2017: OR=0.78 [CI 0.53-1.15]; ≥3 lobes 1990-2002: OR=0.37 [CI 0.22-0.62]; 2003-2011: OR=0.73 [CI 0.43-1.23]; 2012-2017: OR=1.46 [CI 0.91-2.42]). Etiology, age at surgery and invasive recordings were further predictors for the odds for seizure freedom.

Conclusion:

Over the past 28 years, the success of resective surgery for patients with exTLE has improved. At the same time, the number of exTLE patients being evaluated for surgery increased as well as their odds for undergoing surgery.

Effects of left and right medial temporal lobe resections on hemodynamic correlates of negative and neutral scene processing

Enhanced visual cortex activation by negative compared to neutral stimuli is often attributed to modulating feedback from the amygdala, but evidence from lesion studies is scarce, particularly regarding differential effects of left and right amygdala lesions. Therefore, we compared visual cortex activation by negative and neutral complex scenes in an event‐related fMRI study between 40 patients with unilateral temporal lobe resection (TLR; 19 left [lTLR], 21 right [rTLR]), including the amygdala, and 20 healthy controls. We found preserved hemodynamic emotion modulation of visual cortex in rTLR patients and only subtle reductions in lTLR patients. In contrast, rTLR patients showed a significant decrease in visual cortex activation irrespective of picture content. In line with this, healthy controls showed small emotional modulation of the left amygdala only, while their right amygdala was activated equally by negative and neutral pictures. Correlations of activation in amygdala and visual cortex were observed for both negative and neutral pictures in the controls. In both patient groups, this relationship was attenuated ipsilateral to the TLR. Our results support the notion of reentrant mechanisms between amygdala and visual cortex and suggest laterality differences in their emotion‐specificity. While right medial temporal lobe structures including the amygdala seem to influence visual processing in general, the left medial temporal lobe appears to contribute specifically to emotion processing. Still, effects of left TLR on visual emotion processing were relatively subtle. Therefore, hemodynamic correlates of visual emotion processing are likely supported by a distributed cerebral network, challenging an amygdalocentric view of emotion processing.

A genome-wide association study in autoimmune neurological syndromes with anti-GAD65 autoantibodies

Autoimmune neurological syndromes (AINS) with autoantibodies against the 65 kDa isoform of the glutamic acid decarboxylase (GAD65) present with limbic encephalitis, including temporal lobe seizures or epilepsy, cerebellitis with ataxia, and stiff-person-syndrome or overlap forms. Anti-GAD65 autoantibodies are also detected in autoimmune diabetes mellitus, which has a strong genetic susceptibility conferred by human leukocyte antigen (HLA) and non-HLA genomic regions. We investigated the genetic predisposition in patients with anti-GAD65 AINS. We performed a genome-wide association study (GWAS) and an association analysis of the HLA region in a large German cohort of 1214 individuals. These included 167 patients with anti-GAD65 AINS, recruited by the German Network for Research on Autoimmune Encephalitis (GENERATE), and 1047 individuals without neurological or endocrine disease as population-based controls. Predictions of protein expression changes based on GWAS findings were further explored and validated in the CSF proteome of a virtually independent cohort of 10 patients with GAD65-AINS and 10 controls. Our GWAS identified 16 genome-wide significant (P < 5 × 10-8) loci for the susceptibility to anti-GAD65 AINS. The top variant, rs2535288 [P = 4.42 × 10-16, odds ratio (OR) = 0.26, 95% confidence interval (CI) = 0.187-0.358], localized to an intergenic segment in the middle of the HLA class I region. The great majority of variants in these loci (>90%) mapped to non-coding regions of the genome. Over 40% of the variants have known regulatory functions on the expression of 48 genes in disease relevant cells and tissues, mainly CD4+ T cells and the cerebral cortex. The annotation of epigenomic marks suggested specificity for neural and immune cells. A network analysis of the implicated protein-coding genes highlighted the role of protein kinase C beta (PRKCB) and identified an enrichment of numerous biological pathways participating in immunity and neural function. Analysis of the classical HLA alleles and haplotypes showed no genome-wide significant associations. The strongest associations were found for the DQA1*03:01-DQB1*03:02-DRB1*04:01HLA haplotype (P = 4.39 × 10-4, OR = 2.5, 95%CI = 1.499-4.157) and DRB1*04:01 allele (P = 8.3 × 10-5, OR = 2.4, 95%CI = 1.548-3.682) identified in our cohort. As predicted, the CSF proteome showed differential levels of five proteins (HLA-A/B, C4A, ATG4D and NEO1) of expression quantitative trait loci genes from our GWAS in the CSF proteome of anti-GAD65 AINS. These findings suggest a strong genetic predisposition with direct functional implications for immunity and neural function in anti-GAD65 AINS, mainly conferred by genomic regions outside the classical HLA alleles.

Right medial temporal lobe structures particularly impact early stages of affective picture processing

Human vision prioritizes emotional stimuli. This is reflected in stronger electrocortical activation in response to emotional than neutral stimuli, measurable on the surface of the head. Feedback projections from brain structures deep within the medial temporal lobes (mTLs), in particular the amygdala, are thought to give rise to this phenomenon, although causal evidence is rare. Given the many pathways involved in visual processing, the influence of mTL structures could be restricted to specific time windows. Therefore, we delineate the temporal dynamics of the impact of right mTL structures on affective picture processing, investigating event-related potentials (ERPs) in 19 patients (10 female) with right mTL resections and 19 individually matched healthy participants, while they viewed negative and neutral scenes. Groups differed significantly at early- and mid-latency processing stages. Patients with right mTL resection, unlike controls, showed no (P1: 90-140 ms) or marginal (N1: 170-220 ms) emotion modulation. At mid-latency (early posterior negativity: 220-370 ms), emotion modulation over the ipsi-resectional right hemisphere was smaller in patients than in controls, but groups did not differ over the left hemisphere. During late parietal positivities (400-650 ms and 650-900 ms), both groups had similar emotion modulation. Our results demonstrate that right mTL structures attenuate particularly early processing of affectively negative scenes. This is theoretically consistent with an initial amygdala-dependent feedforward sweep in visual emotion processing whose absence is successively compensated. Findings specify the impact of right mTL structures on emotional picture processing and highlight the value of time-resolved measures in affective neuroscience.

Hypochondroplasia and temporal lobe epilepsy - A series of 4 cases

Hypochondroplasia is a skeletal dysplasia syndrome with an autosomal dominant inheritance. It may be associated with temporal lobe epilepsy. We present a series of four patients (two female, two male) with hypochondroplasia who presented at our center with drug refractory epilepsy. Clinical details and EEG and MRI findings led to a diagnosis of temporal lobe epilepsy in all four cases. The MRI findings indicate the epilepsy in hypochondroplasia may be associated with bilateral temporal lobe dysgenesis.

Limbic encephalitis

Limbic encephalitis (LE) is a clinical syndrome defined by subacutely evolving limbic signs and symptoms with structural and functional evidence of mediotemporal damage in the absence of a better explanation than an autoimmune (or paraneoplastic) cause. There are features common to all forms of LE. In recent years, antibody(ab)-defined subtypes have been established. They are distinct regarding underlying pathophysiologic processes, clinical and magnetic resonance imaging courses, cerebrospinal fluid signatures, treatment responsivity, and likelihood of a chronic course. With immunotherapy, LE with abs against surface antigens has a better outcome than LE with abs to intracellular antigens. Diagnostic and treatment challenges are, on the one hand, to avoid overlooking and undertreatment and, on the other hand, to avoid overdiagnoses and overtreatment. LE can be conceptualized as a model disease for the consequences of new onset mediotemporal damage by different mechanisms in adult life. It may be studied as an example of mediotemporal epileptogenesis.

DNA methylation-based classification of malformations of cortical development in the human brain

Malformations of cortical development (MCD) comprise a broad spectrum of structural brain lesions frequently associated with epilepsy. Disease definition and diagnosis remain challenging and are often prone to arbitrary judgment. Molecular classification of histopathological entities may help rationalize the diagnostic process. We present a retrospective, multi-center analysis of genome-wide DNA methylation from human brain specimens obtained from epilepsy surgery using EPIC 850 K BeadChip arrays. A total of 308 samples were included in the study. In the reference cohort, 239 formalin-fixed and paraffin-embedded (FFPE) tissue samples were histopathologically classified as MCD, including 12 major subtype pathologies. They were compared to 15 FFPE samples from surgical non-MCD cortices and 11 FFPE samples from post-mortem non-epilepsy controls. We applied three different statistical approaches to decipher the DNA methylation pattern of histopathological MCD entities, i.e., pairwise comparison, machine learning, and deep learning algorithms. Our deep learning model, which represented a shallow neuronal network, achieved the highest level of accuracy. A test cohort of 43 independent surgical samples from different epilepsy centers was used to test the precision of our DNA methylation-based MCD classifier. All samples from the test cohort were accurately assigned to their disease classes by the algorithm. These data demonstrate DNA methylation-based MCD classification suitability across major histopathological entities amenable to epilepsy surgery and age groups and will help establish an integrated diagnostic classification scheme for epilepsy-associated MCD.

Enhancing Safety in Epilepsy Surgery (EASINESS): Study Protocol for a Retrospective, Multicenter, Open Registry

Introduction: Optimizing patient safety and quality improvement is increasingly important in surgery. Benchmarks and clinical quality registries are being developed to assess the best achievable results for several surgical procedures and reduce unwarranted variation between different centers. However, there is no clinical database from international centers for establishing standardized reference values of patients undergoing surgery for mesial temporal lobe epilepsy.

Design: The Enhancing Safety in Epilepsy Surgery (EASINESS) study is a retrospectively conducted, multicenter, open registry. All patients undergoing mesial temporal lobe epilepsy surgery in participating centers between January 2015 and December 2019 are included in this study. The patient characteristics, preoperative diagnostic tools, surgical data, postoperative complications, and long-term seizure outcomes are recorded.

Outcomes: The collected data will be used for establishing standardized reference values (“benchmarks”) for this type of surgical procedure. The primary endpoints include seizure outcomes according to the International League Against Epilepsy (ILAE) classification and defined postoperative complications.

Discussion: The EASINESS will define robust and standardized outcome references after amygdalohippocampectomy for temporal lobe epilepsy. After the successful definition of benchmarks from an international cohort of renowned centers, these data will serve as reference values for the evaluation of novel surgical techniques and comparisons among centers for future clinical trials.

Clinical trial registration: This study is indexed at clinicaltrials.gov (NT 04952298).

De novo aphasic status epilepticus: Finally making the diagnosis by long-term EEG

Aphasic status epilepticus (SE) is a rare manifestation of non-convulsive SE (NCSE) and may occasionally be under-recognized. We report a 69-year-old male patient with a pre-existing left parietal oligodendroglioma WHO III after two resections and radio-chemotherapy. The patient was left with some word finding difficulties but had no history of overt seizures. He developed aphasic NCSE, which was only detected by long-term electroencephalography (EEG) monitoring. The 24-hour EEG revealed paroxysmal rhythmic theta-delta activity in left posterior regions that propagated to left temporo-parietal areas. Rhythmic activity appeared every 15-30 min and lasted for 10-110 s. Aphasia was continuously present with superimposed short-lasting clinical deteriorations during the day. Magnetic resonance imaging showed peri-ictal edema on diffusion-weighted images in the insula and fronto-parietal cortex, which supported the diagnosis of SE. NCSE persisted for seven months. The patient recovered upon addition of intravenous phenytoin. One should not only consider aphasic SE when language impairment is episodic, but also when there are prolonged manifestations, especially when the typical differential diagnoses have been excluded. Intravenous therapy may be required to terminate NCSE. With this report, we would like to draw attention to aphasic SE as a rare phenomenon that may be difficult to diagnose and delay management in clinical practice.

Rasmussen encephalitis: Predisposing factors and their potential role in unilaterality

OBJECTIVE

Rasmussen encephalitis (RE) is a progressive and destructive inflammatory disease of one hemisphere. Its cause is unknown. We investigated comorbidity and laterality factors that might predispose to RE.

METHODS

We retrospectively compared the histories of 160 RE patients to those with genetic generalized epilepsy (n = 154) and those with focal cortical dysplasia Type II (FCD II; n = 148).

RESULTS

The median/mean age at symptom onset in RE was 7/10 years (range = 1-53 years), and 58.1% of the patients were female. The female sex predominated in RE patients, with age > 7 years at disease manifestation. The left hemisphere was affected in 65.6%. Perinatal complications (preterm birth, twin pregnancies, early acquired brain lesions) were more frequent in RE than in control patients. Ipsilateral facial autoimmune conditions (scleroderma en coup de sabre, uveitis, or chorioretinitis) were only observed in RE patients (6.9%). Onset of RE was more frequently associated with fever than that of FCD II. In 33.1% of RE patients, ≥1 potential risk factor was found. Interestingly, 11.9% of patients had one-sided early brain lesions or facial autoimmune lesions ipsilateral to subsequent RE; none had such a lesion contralaterally.

SIGNIFICANCE

Perinatal complications and facial autoimmune conditions may act as predisposing factors for RE. Fever might trigger RE manifestation. Further genetic or infectious contributors may be identified in the future. Single or combined hits may be required to elicit or facilitate the start of the disease. Ipsilateral early comorbid lesions or facial autoimmune processes might in part explain the enigmatic unilaterality of RE.

Development and Validation of Prediction Models for Developmental and Intellectual Outcome Following Pediatric Epilepsy Surgery

BACKGROUND AND OBJECTIVES

To (1) identify predictors of postoperative intelligence and developmental quotients (IQ/DQ) and (2) develop and validate clinically applicable IQ/DQ prediction models.

METHODS

We retrospectively analyzed neuropsychological outcomes and their possible determinants for children treated in Bethel and Utrecht since 1990. We performed separate analyses for patients with IQ and those with only DQ available. We developed prediction models based on presurgical determinants to predict dichotomized levels of performance (IQ≥85, IQ≥70, DQ≥50).

RESULTS

IQ/DQ data before and two years after surgery were available for 492 patients (IQ n=365, DQ n=127). At a cutoff-level ±10 points, the chance of improvement was considerably higher than the chance of deterioration (IQ 37.3% vs. 6.6% and DQ 31.5% vs. 15.0%, respectively). Presurgical IQ/DQ was the strongest predictor of postoperative cognition (IQ r=0.85, p<.001, DQ: r=0.57, p<.001).Two IQ models were developed in the Bethel cohort (n=258) and externally validated in the Utrecht cohort (n=102). For DQ, we developed the model in the Bethel cohort and used 10-fold cross-validation. Models allowed good prediction at all three cutoff-levels (correct classification for IQ≥85=86%, IQ≥70=91%, DQ≥50=76%). External validation of the IQ models showed high accuracy (IQ≥85: 0.82, CI 0.75-0.91, IQ≥70: 0.84, CI 0.77-0.92) and excellent discrimination (ROC curves IQ≥85: AUC 0.90, CI 0.84-0.96; IQ≥70: AUC 0.92, CI 0.87-0.97).

DISCUSSION

After epilepsy surgery in children, the risk of cognitive deterioration is very low. Presurgical development has a strong impact on the postoperative trajectory. The presented models can improve presurgical counseling of patients and parents by reliably predicting cognitive outcomes.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that for children undergoing epilepsy surgery presurgical IQ/DQ was the strongest predictor of postoperative cognition.

Transient Global Amnesia (TGA): Younger Age and Absence of Cerebral Microangiopathy Are Potentially Predisposing Factors for TGA Recurrence

Background: Transient global amnesia (TGA) is defined by an acute memory disturbance of unclear etiology for a period of less than 24 h. TGA occurs as a single event in most cases. Prevalence rates of recurrent TGA vary widely from 5.4 to 27.1%. This retrospective study aimed to determine predictors for TGA recurrence.

Methods: Cardiovascular risk profile and magnetic resonance imaging (MRI) of 340 hospitalized TGA patients between 2011 and 2020 were retrospectively analyzed. The median follow-up period amounted to 4.5 ± 2.7 years. Comparisons were made between TGA patients with and without subsequent recurrence.

Results: TGA patients with subsequent recurrence were significantly younger (recurrent vs. single episode, 63.6 ± 8.6 years vs. 67.3 ± 10.5 years, p = 0.032) and showed a lower degree of cerebral microangiopathy compared to TGA patients without recurrence. The mean latency to recurrence was 3.0 years ± 2.1 years after the first episode. In a subgroup analysis, patients with at least five years of follow-up (N = 160, median follow-up period 7.0 ± 1.4 years) had a recurrence rate of 11.3%. A 24.5% risk of subsequent TGA recurrence in the following five years was determined for TGA patients up to 70 years of age without microangiopathic changes on MRI (Fazekas' score 0).

Conclusion: Younger TGA patients without significant microangiopathy do have an increased recurrence risk. In turn, pre-existing cerebrovascular pathology, in the form of chronic hypertension and cerebral microangiopathy, seems to counteract TGA recurrence.

Relative Source Power: A novel method for localizing epileptiform EEG discharges

OBJECTIVE

To validate relative source power (RSP) imaging of extratemporal interictal epileptiform discharges (IEDs).

METHODS

The accuracy of RSP was validated in a cohort of patients with extratemporal focal epilepsy and a confined epileptogenic lesion (<19 cm³) using distance to the lesion, concordance with resected area and postoperative outcome. Performance was compared with three conventional methods: voltage maps, equivalent current dipole and a distributed source model.

RESULTS

Thirty-three of 41 consecutive patients (80%) had IED averages suitable for analysis. While the peak negativity in voltage maps localized above the epileptogenic lesion only in 18 cases, RSP-maps matched in 29 cases (88%, p < 0.0026). Source localization showed a median distance of 9.8 mm from the lesion. Source-regions with 20 mm radius included 98% of all source-to-lesion distances. In the 21 surgical cases, outcome showed a sensitivity of 82.35% and specificity of 50% without significant differences between the three source imaging methods.

CONCLUSIONS

RSP-maps provide a rapid, intuitive and more accurate source estimation than voltage maps. At sublobar level, RSP localizes with an accuracy similar to conventional methods and results of previous studies.

SIGNIFICANCE

The definition of a source region with 20 mm radius helps in guiding further exploration in extratemporal focal epilepsy.

MOG antibody-associated encephalitis secondary to Covid-19: case report

BACKGROUND

While Covid-19 predominantly affects the respiratory system, neurological manifestations including encephalitis occur in some patients, possibly affecting the course and outcome of the disease. Here, we describe a unique case of a young man with Covid-19 and transient MOG-positive encephalitis, with a benign course.

CASE PRESENTATION

A 22-year-old male, with PCR confirmed Covid-19 infection was admitted because of persistent headache. The clinical examination was normal. Neuropsychological testing revealed distinct executive deficits. Brain MRI and cerebrospinal fluid (CSF) analysis were suggestive for encephalitis. Further laboratory examination revealed a serum MOG antibody titre. The headache improved with analgetic treatment and i.v. methylprednisolone. Consequently, the MOG antibody titer decreased and MRI lesions were resolving. The patient made a full recovery, with no signs of deterioration over the following months.

CONCLUSIONS

Covid-19 manifestations in the CNS include encephalitis with variable course and prognosis. This case highlights a possible association between inflammation due to COVID-19 and transient secondary autoimmunity with transient MOG antibodies and atypical clinical presentation.

Clinical characteristics and postoperative seizure outcome in patients with mild malformation of cortical development and oligodendroglial hyperplasia

OBJECTIVE

We describe for the first time clinical characteristics in a series of 20 pre-surgically investigated patients with mild malformation of cortical development with oligodendroglial hyperplasia (MOGHE) who were operated on in our epilepsy center. We aimed to better diagnose this entity and help surgical planning.

METHODS

Data on 20 patients with histologically confirmed MOGHE were retrospectively evaluated as to age at epilepsy onset and operation, seizure semiology, magnetic resonance imaging (MRI) localization, electroencephalography (EEG) patterns, extent of the operative resection, and postoperative seizure outcome.

RESULTS

Epilepsy began mainly in early childhood; however, symptoms did not manifest until adolescence or adulthood in 30% of patients. All patients had pathologic MRI findings. In 45% of patients the lesion was initially overlooked. Most commonly, the lesion was seen in the frontal lobe. Seizure semiology was characterized as follows: (1) epileptic spasms at epilepsy onset were common and (2) nocturnal hyperkinetic seizures during the course of the disease were rare. EEG always showed frequent interictal epileptic discharges. Two peculiar patterns were observed: (1) during sleep stage I-II, sub-continuous repetitive (0.5-1.5/s) unilateral plump spike/polyspike slow waves were seen and (2) during wakefulness, unilateral paroxysms of 2-2.5/s spike-wave complexes occurred. In total, 60% of patients were seizure-free 1 year postoperatively. Postoperative seizure outcome was positively correlated with the extent of resection, age at epilepsy onset, and age at operation. Postoperative long-term outcomes remained stable in patients undergoing larger operations.

SIGNIFICANCE

MRI, EEG, and semiology already contribute to the diagnosis of probable MOGHE preoperatively. Because postoperative seizure outcomes depend on the extent of the resection, prior knowledge of a probable MOGHE helps to plan the resection and balance the risks and benefits of such an intervention. In patients undergoing larger operations, epilepsy surgery achieved good postoperative results; the first long-term outcome data were stable in these patients.

[Women with epilepsy before and during pregnancy: a case series of outpatient counseling in a tertiary epilepsy center]

BACKGROUND

Data of large pregnancy registries have improved the recommendations for women with epilepsy before pregnancy. Monotherapy containing antiepileptic drugs with a low malformation rate (lamotrigine or levetiracetam) is recommended as well as preconceptional folic acid supplementation, while valproic acid should be avoided. The practicability of these recommendations remains controversial.

METHODS

Retrospective case series of 160 women with epilepsy over a period of 5 years who were advised in our outpatient department before and during pregnancy.

RESULTS

Only 18.9% of women presented with valproic acid. Even without valproic acid, complications or emergency admissions rarely occurred under specialist supervision. In our case series, lamotrigine proved to be less effective and less controllable than other drugs during pregnancy. Levetiracetam also has a low malformation rate, but showed a better effect on seizure outcome during pregnancy than lamotrigine. Only 12% of women who wanted to have children took folic acid.

CONCLUSION

This case series comes from a tertiary center; the referred women were mainly accompanied by neurologists with special expertise in epileptology. In this group valproate could be avoided in most cases. Lamotrigine is probably less effective due to the drop in blood levels during pregnancy. Levetiracetam seems to be a good alternative, working well against focal and generalized seizures. Folic acid may be taken later than recommended.

Reading and the visual word form area (VWFA) - Management and clinical experience at one epilepsy surgery center

OBJECTIVE

Presurgical evaluation has no established routine to assess reading competence and to identify essential "not to resect" reading areas. Functional models describe a visual word form area (VWFA) located in the midfusiform gyrus in the dominant ventral occipito-temporal cortex (vOTC) as essential for reading. We demonstrate the relevance and feasibility of invasive VWFA-mapping.

METHODS

Four patients with epilepsy received invasive VWFA-mapping via left temporo-basal strip-electrodes. Co-registration of the results and additional data from the literature led to the definition of a region of interest (ROI) for a retrospective assessment of postoperative reading deficits by a standardized telephone-interview in patients with resections in this ROI between 2004 and 2018.

RESULTS

Electrical cortical stimulation disturbed whole word recognition and reading in four patients with structural epilepsy. Stimulation results showed distribution in the basal temporal lobe (dorsal mesencephalon to preoccipital notch). We identified 34 patients with resections in the ROI of the dominant hemisphere. Of these, 15 (44.1%) showed a postoperative reading deficit with a mean duration of 18.2 months (+/-32.4, 0.5-122). Six patients suffered from letter-by-letter (LBL) reading. Two patients had permanent LBL reading after resection in the ROI.

SIGNIFICANCE

We present evidence on the functional relevance of the vOTC for reading by (1) extra-operative cortical stimulation of the VWFA and by (2) a retrospective case study of reading deficits in patients operated in this area. Reading assessments and data concerning essential reading structures should be included in the presurgical evaluation of patients with lesions in the left vOTC.