Abstracts

Rationale:

This study aimed to investigate high-frequency oscillations (HFOs) in a diverse neonatal EEG dataset, hypothesizing their high prevalence in severe neonatal epilepsy and scarcity in cases of acute provoked seizures.

Methods:

Neonates were selected from a population-based EEG database with various diagnoses, including neonatal-onset epilepsy, chronic brain disease, acute stroke, perinatal hypoxic ischemic encephalopathy (HIE), acute brain infection, or no neurological diagnoses. After excluding artifacts, 82 EEGs were analyzed, with 18 containing ictal data and 80 containing interictal data. Sleep stages, seizures, and HFOs were manually marked, and outcomes were assessed from medical records. The certainty of HFO findings was also scored.

Results:

HFOs were detected in 23 neonates (28%). Among the 18 neonates with ictal data, 10 exhibited ictal HFOs (median rate 0.53/min, range 0.07 – 6.41/min), while among the 80 with nonictal data, 18 showed nonictal HFOs (median rate 0.17/min, range 0.01 – 20.99/min). Certainty of the HFO finding was rated certain in 13 cases. Significant differences were observed in nonictal HFO occurrence and rate among different diagnostic groups (when considering certain HFOs), being highest in neonates with neonatal-onset developmental and epileptic encephalopathy (DEE). Nonictal HFO occurrence and rate were also associated with later development of infantile-onset DEE (p < 0.05), except in HIE neonates. In contrast, ictal HFOs were not associated with the etiological group or the development of later epilepsy, being common in neonates with acute provoked seizures.

Conclusions:

Neonatal nonictal HFOs seem rare but are associated with severe early-onset epilepsy, while ictal HFOs are relatively common in neonates with acute provoked seizures and are not associated with epilepsy. A comprehensive understanding of HFOs’ predictive value in epilepsy requires further investigation, including follow-up EEGs beyond the neonatal period.

Rationale:

FINCA is a neurodevelopmental and multiorgan disease (OMIM 618278) caused by recessive variants in the NHLRC2 gene encoding a protein with undefined function (Uusimaa J et al. 2018). Our knockout and knockin mice showed the essential role of NHLRC2 in embryonic development, and revealed altered proteins associated with endo- and autolysosomal pathways, and RNA homeostasis (Hiltunen AE et al. 2020, 2022). Since our initial report in 2018, thirty-three patients have been described worldwide including our novel FINCA patients (Tallgren A et al. 2023 and this abstract)

Methods:

We collected clinical and laboratory data on five FINCA patients identified by whole exome sequencing revealing biallelic NHLRC2 variants. We studied NHLRC2 expression in human brain autopsy samples, and immune response of FINCA mice by serum cytokine analysis post lipopolysaccharide injection. T-cell populations, activation, and cytokine production of FINCA mouse splenocytes were analyzed by flow cytometry.

Results:

All the FINCA patients presented with neurodevelopmental disorder, recurrent infections, and macrocytic anemia. Patients with infantile-onset phenotype with decreased immunoglobin levels died due to multiorgan failure, while the eldest 61-year-old patient presented with epileptic encephalopathy. Autopsy samples revealed widespread NHLRC2 expression in the brain at a lower intensity in patients compared to control. FINCA mice and their splenocytes revealed compromised immune response.

Conclusions:

Our data expand the clinical spectrum of FINCA disease including Fibrosis, Infection susceptibility, Immunodeficiency, Intellectual disability, Neurodevelopmental disorder, Neurodegeneration, Chronic Anemia, and Cerebral Angiomatosis. The pathogenic NHLRC2 variants lead to defective immune response as one of the primary manifestations of FINCA disease.

Rationale:

Recessive LAMC3 mutations are recognized behind epilepsies with cortical malformations characterized by polymicrogyria and pachygyria. Our objective is to describe the clinical picture of four patients with previously undescribed LAMC3 mutation.

Methods:

All epilepsy patients treated in Kuopio Epilepsy Center are offered a possibility to participate in a scientific study investigating biomarkers in epilepsy. Currently we are re-evaluating patients with developmental and/or epileptic encephalopathies. If the etiology of epilepsy remains unknown in the clinical setting, we are performing Whole Exome Sequencing to recognize the genetic causes.

Results:

Among our study population we recognized three patients with similar homozygous LAMC3 (c.1866del, p.(Phe623Serfs*10)) frameshift mutations and one patient with a compound heterozygous mutation where the same frameshift mutation was combined with an intronic LAMC3 c.4231-12C>G mutation. All these patients have severe epilepsy with either bilateral agyria-pachygyria or bilateral polymicrogyria. Cortical malformations involve the occipital lobes in all these patients. Epilepsy phenotype is variable as two of our patients have developmental and epileptic encephalopathy with epileptic spasms progressing to Lennox Gastaut syndrome and intellectual disability. The other two patients have focal epilepsy without marked cognitive deficit. LAMC3 (c.1866del, p.(Phe623Serfs*10)) frameshift mutation is enriched in the Finnish population.

Conclusions:

Only a few patients with epilepsy caused by recessive LAMC3 mutations have been described in the literature. The mutations discovered in our patients have not previously been published. Clinical phenotype appears to be more varied than previously assumed. Patients with a milder phenotype and normal cognition have probably remained unrecognized.

Rationale:

Infantile spasm syndrome (ISs, West syndrome) is an infantile epilepsy syndrome, which is defined by typical seizures called infantile spasms, typical EEG abnormalities and developmental arrest or retardation. The etiologies of the syndrome are very variable, including genetic, structural, or metabolic abnormalities, for example. In third of the cases, the etiology remains unknown. Recognizing the symptoms especially in an early state can be difficult which may lead to delays in diagnosis and treatment. The outcome of the syndrome depends much on the etiology and early beginning of an appropriate treatment, and on the response to treatment. A poor response to treatment or delay in beginning of the treatment may lead to more severe developmental arrest, intellectual retardation, and evolution of the epilepsy syndrome.

Methods:

The aim of this study was to investigate the evolution of the clinical symptoms and functional ability of ISs patients from beginning of the symptoms to adulthood. In addition, the aim of the review of the literature was to evaluate the development of the diagnostic methods during last years, and to evaluate whether recent development has influenced to the outcome of the patients. The sample of this study was 25 patients with ISs diagnosis born in 1993-2006 in Kuopio University Hospital area. Their patient records, brain imaging results, and genetic diagnostic records were investigated, and based on these the long-term outcome and evolution of the syndrome were evaluated up till year 2022.

Results:

A third of the patients were dead during the follow-up time. Four of five of the patients alive were completely or partly dependent on outside care, and only one of these five was independent in functional ability. One half of the patients had recovered seizure-free, another half had still a difficult to treat epilepsy, and some patients had developed another epilepsy syndrome, typically Lennox-Gastaut. Genetic and structural abnormalities were the main factors explaining the etiology among the symptomatic patients. The best response to treatment and the best outcome were among the patients who had unknown etiology, and to whom the treatment had begun in time.

Conclusions:

The outcome of infantile spasm syndrome has improved somewhat during recent years, due to development of diagnostic methods, better recognition of the symptoms, and a systematic diagnostics and treatment. Still, the mortality is high even in long term and in most patients the epilepsy remains active through life. Due to the development of genetic diagnostics, in future the etiologies can be defined more specifically and more targeted individual treatment can be developed.

Rationale:

The Lennox-Gastaut syndrome (LGS) is rare and severe form of epilepsy, which usually begins in childhood. Natural course of the syndrome and effective treatment are still poorly understood. The aim of the study was to elucidate the natural course and prognosis of the LGS.

Methods:

25 patients with LGS were identified from the Kuopio Epilepsy Center epilepsy biomarker research database. Their epilepsy syndrome were reassessed according to the new ILAE diagnostic criteria and natural history was identified from the medical record for a mean follow-up period of 14,7 years (range 1,5-25 years).

Results:

After the reassessment 18 out of these 25 patients were verified to fulfill the current diagnostic criteria of LGS. Three patients had tuberosis sclerosis, 2 Down syndrome, 3 other genetic etiology. 4 patients had had infantile spasm syndrome preceding LGS. 10 (56%) patients were not able to walk and used wheel-chair. The most effective treatments were valproate and vagal nerve stimulator. During the evolution the EEG slow spike-and-wave features, frequency of atonic seizures and the overall seizure frequency decreased. Age of onset of seizures, etiology of the syndrome and comorbidities correlated to the outcome.

Conclusions:

Our results emphasize the importance of re-evaluation of diagnosis to ensure the right diagnose. Diagnostics of Lennox-Gastaut syndrome is challenging and therefore the diagnostic criterion should be clear. Current criteria are not always suitable for adult patients due to the evolution of the syndrome. Correct diagnosis is important for targeted treatment correctly and best quality of life of the patient.

Rationale:

Fenfluramine is approved for the treatment of seizures associated with Lennox-Gastaut syndrome (LGS) in patients ≥2y in the US, UK, and Europe. The seizure-free days percentage in fenfluramine-treated LGS patients in a randomized controlled trial (RCT) and its open-label extension (OLE) was evaluated post-hoc.

Methods:

RCT: Patients (2-35y) were randomized to fenfluramine 0.2 or 0.7mg/kg/day (max: 26mg/day), or placebo following 4-week baseline. Titration and maintenance (T+M) were 2 and 12 weeks, respectively. OLE: Patients initiated 0.2mg/kg/day fenfluramine (1 month). Thereafter, doses (0.5mg/kg/day) were titrated based on effectiveness/tolerability. Seizure-free days percentage for fall-associated seizures, including generalized tonic-clonic seizures (GTCS), and all countable (motor) seizures was calculated using pretreatment RCT baseline vs T+M and Month 2 to end-of-study.

Results:

RCT: Mean change from baseline to T+M in seizure-free days percentage for placebo (n=87), 0.2 (n=89), and 0.7mg/kg/day (n=87) was: 4.5, 8.2, and 11.3 for fall-associated seizures; 0.6, 4.4, and 5.4 for GTCS; 4.1, 8.0, and 7.5 for countable seizures. The ratio for mean change in percentage of seizure days in 0.7mg/kg/day vs placebo was 2.5. OLE: Mean change from baseline in seizure-free days percentage for 0.5mg/kg/day (n=60) was: 9.7, 12.3, and 15.0 for fall-associated seizures; 1.1, 6.1, and 6.7 for GTCS; 7.7, 9.8, 12.5 for countable seizures.

Conclusions:

The seizure-free days percentage increased for all analyzed seizures which may improve quality of life for patients/caregivers. GTCS is the highest risk factor for sudden unexpected death in epilepsy; increasing GTCS-free days may improve outcomes.

Rationale:

International treatment guidance is lacking for prolonged seizures (PS) and seizure clusters (SC). We previously reported consensus recommendations on definitions of different PS and SC types, and terminology for treatments to prevent progression to more severe types/seizure emergency: rapid and early seizure termination (REST) to terminate an ongoing seizure; acute cluster treatment (ACT) to prevent the next/further seizures in a cluster. Here we present consensus statements regarding which patients could benefit from intervention and the ideal outpatient-treatment timing. Methods: An expert working group (12 European/American paediatric /adult epileptologists, neurologists, pharmacologists) used modified-Delphi approach to develop and anonymously vote on recommendations (consensus: ≥75% voting ‘Agree’/‘Strongly agree’). Results: Consensus was reached on which patients with specific seizure types should be offered REST-medication and/or ACT, and advice to patients/caregivers regarding outpatient-treatment timing. All experts agreed that all patients with PS experience should be offered REST-medication, and all with SC experience should be offered ACT. When prescribing REST-medication and/or ACT, seizure-action plans should be agreed in consultation with patients/caregivers. All agreed that for patients whose main seizure pattern is SC, REST-medication and/or ACT should be considered at first seizure-onset; 11/12 agreed that patients with PS history and recognisable onset pattern should administer REST-medication as early as possible.

Conclusions:

High agreement levels were reached on which patients with specific seizure types could benefit from REST-medication and ACT, and advice to patients/caregivers regarding outpatient-treatment timing. These recommendations will provide clearer guidance to clinicians, patients, and caregivers, and help establish REST as new PS-management paradigm.

Stereo-EEG (sEEG) is a part of neurophysiological investigation necessary for defining the seizure onset zone (SOZ). Defining SOZ is currently the gold standard for estimating the EZ, but its resection does not always lead to seizure freedom. Hence, new markers for the EZ are urgently needed. High-frequency activity, and fast ripples (FR) in particular, recorded with depth electrodes during sEEG are a potential biomarker for EZ. Another essential part of SEEG monitoring is intracranial direct electrical stimulation (iDES). It affects FR and the results of stimulation may harbor new information about EZ. The study was carried out on clinical data of patients who underwent sEEG monitoring at Helsinki University Hospital in 2018-2022. The patients were implanted with depth electrodes and up to 80-110 channels per patient were recorded. The channels were stimulated in an orderly fashion with bipolar stimulation. The sleep and stimulation sEEG data were analysed in MATLAB software with in-house-developed scripts used in previous studies. Five minute long periods of pre- and post-stimulus recordings were used for analysis. Collected data was analysed using linear mixed models with averaging the FR pre- to post-stimulus rate changes, sleep FR rates and binomial SOZ variable across electrodes and using SOZ as an outcome variable. Sleep FR rate, but not the FR rate change between pre- and post-stimulus period, was statistically significant according to the model. That allows us to dismiss the accumulative effect of stimulation and consider the changes happening during the electrical stimulation not affected on a larger time-scale.

Rationale:

Hemispherotomy refers to epilepsy surgery techniques in which the hemisphere with unilateral multilobar pathology is disconnected from the healthy side in patients with severe epilepsy. Despite previous studies highlighting its efficacy in leading to seizure freedom, there are limited evidence on complication rates for vertical parasagittal hemispherotomy (VPH) and the impact of incomplete disconnection on long-term seizure freedom. This study aims to identify prevalent VPH complications and the typical sites of possible incomplete disconnection.

Methods:

We performed a retrospective evaluation on all patients that had undergone VPH during 1991-2022 at our institution. All available postoperative MRIs (31/48, 64.6%) were reviewed (AK). Before 2010, postoperative MRI was only performed if seizures recurred. Two-year follow-up data was available for 45 patients, and six-month data for 3.

Results:

Primary VPH led to seizure freedom in 71% of the patients. The mean number of antiseizure medications decreased by 51%. Surgical complications occurred in 14 patients (29%); 4 cases were classified as transient and resolved during follow-up without surgical intervention. Non-transient complications included 8 cases of hydrocephalus requiring surgical treatment, 1 shunted subdural hygroma, and 1 cerebrospinal fluid leakage from the wound. Residual connections were present in 17 patients (36% of the total cohort), primarily in the temporomesial region. 8 patients remained seizure-free despite visible residual connection. Acquired etiology (OR 46.28, p = 0.010) correlated positively with seizure freedom.

Conclusions:

VPH is a challenging surgical technique but also a highly effective treatment for drug resistant epilepsy. Incomplete disconnection does not necessarily preclude seizure freedom.

Rationale:

The brain’s perivascular space (PVS) is vital for clearing metabolic waste and abnormal proteins from the interstitial space. Brain diseases can lead to PVS dilatation.

Methods:

A retrospective analysis included 1024 epileptic patients and 138 non-CNS disease patients, each undergoing 3 Tesla MRI. Thin-sliced T2WI and 3D-T1WI images were used to identify dilated perivascular spaces (PVS)

Results:

Epileptic patients had a higher prevalence of dilated perivascular spaces (PVS) (13% vs 29%, p<0.001). Among the 319 of 1024 epileptic cases who had undergone follow-up MRI, PVS remained unchanged in 312 (97.8%) cases during a mean interval of 3.4 ± 2.5 years. Punctate white matter hyperintensity (WMH) was present in 478 of 1024 (46.7%) epileptic patients. In the adult epileptic cases, the dilated PVS group had a significantly higher incidence of punctate WMH (72.3% vs. 56.9%, p=0.002) compared to the nondilated PVS group. Higher Fazekas score (OR 1.299 95% CI 1.024-1.646, p=0.031), presence of punctate WMH (OR 1.540 95% CI 1.125-2.108, p=0.007), and male epileptic patients (OR 1.385 95% CI 1.029-1.865, p=0.032) were independently associated with dilated PVS.

Conclusions:

Enhanced PVS visibility is linked to epilepsy, with dilated PVS likely appearing before the initial seizure and showing minimal changes over the disease course. A high occurrence of cerebral WMH suggests small vessel damage, even in young epileptic patients. Early intervention is crucial to prevent subsequent cerebral vascular damage, thereby reducing the risk of long-term cognitive impairment.

Rationale:

Positive misdiagnoses of epilepsy are not uncommon and can be very harmful to the patient. “Overreading” abnormalities in the electroencephalogram (EEG) often plays a part in the false diagnosis. With better training in EEG reading, some of the misdiagnoses could be avoided.

Methods:

EpiCurrents is a JavaScript library for displaying electrophysiological studies in a web browser. It is modular in design and capable of supporting multiple study types (including EEG and MEG) in different file formats (including EDF). The user interface can be made interactive and to emulate professional EEG software. Python scripts and parts of the Python MNE library can be utilized for signal analysis, for example to calculate and display voltage maps of individual EEG waveforms. The library supports machine learning models in ONNX format, making it also suitable for teaching AI-assisted EEG reading. In addition to neurophysiological studies, support for radiological imaging studies is under consideration.

Results:

The EEGonline project by the Neurological Association of South Africa and University of Cape Town is planning to incorporate EpiCurrents as a part of their EEG learning web platform.

Conclusions:

EpiCurrents is developed as open-source software and is free for anyone to use and adapt to suit their needs. It runs entirely in the end-user’s web browser and doesn’t require any special web server software. The project is supported by the International Federation of Clinical Neurophysiology.

Rationale:

Progressive myoclonic epilepsy type 1 (EPM1) is a neurodegenerative disease with onset from six to 16 years, stimulus-sensitive myoclonus, and generalized tonic-clonic epileptic seizures. EPM1 is caused by biallelic alterations in the cystatin B (CSTB) gene. Despite a progressive course, the phenotype severity varies from patient to patient. Our research aims to uncover the role apolipoprotein E (apoE) gene has in modifying phenotypic diversity in EPM1.

Methods:

As part of our large EPM1 study, apoE genotypes were determined for 68 genetically verified EPM1 patients homozygous for the expansion mutation in the CSTB gene (36 males, 32 females). The mean disease duration at the study visit was 24 years (range 4-44 years). The Unified Myoclonus Rating Scale (UMRS), neuropsychological assessments, and clinical data were stratified by apoE genotypes to explore potential correlations with EPM1 severity.

Results:

ApoE genotypes in our study population predominantly featured ε3/ε3 (n=38), along with occurrences of 17 ε3/ε4, eight ε2/ε3, four ε4/ε4, and one ε2/ε2. The mean onset age of EPM1 was 10 years (range 5-20 years). No significant difference between apoE allele groups were observed for the UMRS (p=0.29), Verbal Intelligence Quotient (p=0.26), Performance Intelligence Quotient (p=0.38), onset age (p=0.17), and apoE genotypes. Subsequent analyses will be performed to further explore phenotypic variability.

Conclusions:

No significant association between apoE genotypes and the phenotype variations were found. The current study only explored cross-sectional phenotypic data, whereas in the future we aim to provide more natural history data of EPM1 and correlate long-term deep phenotypic data with further genetic analyses.

Rationale:

Progressive myoclonic epilepsy type 1 (EPM1) is an autosomal recessive disorder caused by mutations in the cystatin B (CSTB) gene and is also known as Unverricht Lundborg Disease (ULD). Affected individuals have tonic-clonic seizures, stimulus-sensitive and action-activated myoclonus, myoclonus during sleep, and dysarthria. CSTB functions as an intracellular thiol protease inhibitor. Also, it plays a key role in brain development and regulates mitochondrial function, apoptosis, cell migration, and differentiation. Recent studies have shown that EPM1 patients and EPM1 knockout mice have GABAergic neuron impairment. Our study investigates the role of CSTB in regulating GABAergic neuron functions in patient-derived cells.

Methods:

Induced pluripotent stem cells (iPSCs) were generated from EPM1 patients’ dermal fibroblasts and differentiated to GABAergic neurons by forced expression of Ascl1 and Dlx2. Validation of cell identity has been performed with quantitative PCR and immunocytochemistry-based methods including western blot and flow cytometry.

Results:

CSTB expression is significantly reduced in the patient iPSCs when compared to control cells. Preliminary data suggests alterations in mitochondrial function, decreased proliferation and an increased tendency to undergo apoptosis in mutant cells. In addition, reduced GABAergic marker expression is detected in the patient neurons after differentiation.

Conclusions:

The patient derived neurons recapitulate features seen in EPM1 patients and provide a tool to study the role of GABAergic neurons in EPM1 disease progression.

Rationale:

Epilepsy surgery is a successful treatment option for patients with medically refractory focal epilepsy. We present a protocol, which is a part of multidisciplinary project, aiming to establish connection between preoperative clinical phenotype analyses of epilepsy surgery candidates and comprehensive analyses encompassing systematic, molecular, functional, histological, and morphological aspects, conducted on resected tissue.

Methods:

All the patients who give their informed consent and are evaluated preoperatively before epilepsy surgery at Kuopio Epilepsy Center are recruited to our large Epilepsy Biomarker Study. Optimal surgical candidates are identified by clinical positive prognostic factors of epilepsy surgery and robust evidence for epileptogenic zones (EZ) delineation. Standard epilepsy surgery evaluation includes neurological, neuroimaging, neurophysiological, neuropsychological, and more often also genetic assessments.

Results:

We have started efforts to structure the clinical data in the hospital with StellarQ neuroplatform especially regarding etiology and functional capacity of the patient. Electronical seizure calendar (dates of seizures by seizure types) and antiseizure medication (drugs and doses) are integrated and displayed on one screen. In our biomarker study standard clinical data modalities, genetics and standard preoperative assessments are transferred into multidisciplinary REDCap-database and other research databases, containing electroencephalography (EEG) and magnetic resonance imaging (MRI) data. These deep phenotypic data will be then correlated with preoperative experimental MRI sequences and advanced multidisciplinary analyses of the resected tissue.

Conclusions:

Combining multidisciplinary clinical preoperative workup with postoperative histological, and imaging findings, might assist to gain comprehensive understanding of EZ localization especially in non-lesional focal epilepsy and improve our understanding of the pathophysiology of focal epilepsy.

Rationale:

Epilepsy remains a profound health challenge globally, impacting a significant proportion of the population. Despite advancements in medical interventions, a subset of focal epilepsy cases proves refractory to pharmacological treatments, necessitating surgical intervention. The accurate identification of epileptogenic tissue stands as a determinant for the success of surgical procedures and the subsequent achievement of a seizure-free life for patients.

Methods:

This study presents an investigational 3T MRI protocol for assessing individuals undergoing epilepsy surgery as a part of multiscale epilepsy project in Kuopio University Hospital (KUH) in collaboration with University of Eastern Finland (UEF). The protocol encompasses anatomical T1-weighted images, magnetic resonance encephalography (MREG) for tracking brain pulsations, Relaxation along Fictitious Field (RAFF4) for myelin content mapping, multidimensional MRI (MD-MRI) for detailed microstructure imaging, and resting-state functional MRI.

Results:

Protocol has been approved by the authorities and implemented on a 3T Siemens MRI scanner at KUH. Data has been gathered from nine patients with written consent, with additional measurements planned for patients and a control group. The preprocessing pipeline has been established at the UEF.

Conclusions:

This protocol not only demonstrates its feasibility within the clinical settings but also unfolds new perspectives for predicting epileptogenic tissue. By combining novel imaging techniques, it emerges as a promising tool in advancing our understanding of epilepsy and refining surgical strategies for enhanced patient outcomes. The ongoing expansion of data collection and the forthcoming inclusion of a control group underscore the potential impact of this research on the broader landscape of epilepsy management.

Rationale:

In this project, we developed a sample handling pipeline for multiscale assessment of epileptogenic tissue to identify novel therapeutic targets, and to improve diagnosis and stratification of patients for anti-seizure medication and surgical treatment.

Methods:

Patients with drug-resistant focal epilepsy, with different etiologies, are recruited at the Kuopio Epilepsy Center. On the day before the resective surgery, patients undergo magnetic resonance imaging (MRI) with investigational pulse sequences. During the surgery, the epileptogenic zone is resected, and the entire tissue is placed under oxygenation on ice-cold artificial cerebrospinal fluid-solution. The resected tissue is immediately transported to a research laboratory where it is sliced by a neuropathologist to extract tissue for standard diagnostics and subsequent research. Tissue microstructure, cellular heterogeneity and electrophysiological properties of the resected epileptic tissue is studied using two adjacent slices provided for research.

Results:

The developed multimodal and multicenter pipeline offers the opportunity to test emerging in vivo and ex vivo imaging techniques in combination with cutting-edge technologies from the same samples. We optimized the conditions for preserving the resected tissue alive for electrophysiological measurements. The final goal is to rebuild a 3D anatomical model of the resected tissue based on volume reconstruction of the histological sections and ex vivo MRI to provide voxel-to-voxel correspondence for upcoming predictive modeling.

Conclusions:

Our approach introduces a novel pipeline to elucidate the factors that contribute to formation of epileptogenic tissue at structural, functional, and molecular levels, offering valuable insights to guide the diagnosis and subsequent treatment of patients with epilepsy.

Rationale:

Epilepsy is one of the most severe neurological disorders, affecting 50 million adults and children around the world. Despite the available antiseizure medications, around 30% of patients are resistant to therapy. One option for patients with drug-resistant focal epilepsy is the surgical resection of the epileptogenic zone.

Methods:

We have established a pipeline for acute slice preparation from brain biopsies obtained from patients with drug-resistant epilepsy and their subsequent study using state-of-the-art electrophysiological method (whole cell patch clamp).

Results:

By this approach, we evaluated, in a layer and cell subtype-specific manner, neuronal properties in human epileptogenic brain biopsies in the temporal cortex and hippocampus. By patch-clamp measurements we show that under the long-term application of 4-aminopyridine (100M) the excitatory and inhibitory neurons of the cortex and hippocampus exhibit the features of epileptic tissue: the appearance of giant depolarizing currents, synchronization and increased number of action potentials. Thereby we established an ex vivo human model of epileptic seizures.

Conclusion:

With this approach, we are able to evaluate patient specific changes in neuronal operational properties and to test different selective receptor modulators to reduce epileptiform activity ex vivo.

Rationale:

Histopathological features associated with temporal lobe epilepsy (TLE) are routinely assessed by a neuropathologist who visually classifies structural etiology such as hippocampal sclerosis (HS). In this work, we aim to advance histopathological assessments by introducing new tissue markers and employing quantitative analyses, providing a deeper understanding of the underlying etiology.

Methods:

We include resected tissue from patients who underwent anterior temporal lobectomy as a treatment for focal drug resistant TLE. After ex vivo magnetic resonance imaging (MRI), the tissue is processed for histology. Nissl staining is used for overall cytoarchitectonics and myelin for myeloarchitectonics. Immunostaining is performed to detect changes in neuronal morphology and glial cells as markers of inflammation. After digitalization, stained sections will be quantified for cell and myelin density, sole analysis or structure tensor from individual cortical layers and hippocampal subfields.

Results:

In the sclerotic hippocampi the decreased staining intensity of the myelinated fibers were associated with neuronal loss observed with Nissl staining. Our next steps are to systematically quantify the findings and analyze the cortical samples which showed negligible structural alterations in the clinical histopathology analysis.

Conclusions:

Performing quantitative analyses and incorporating novel histological markers into neuropathological assessments are crucial steps in characterizing the structural alterations associated with TLE, aiming to enhance treatment outcomes. Also, in this project, the validation of MRI findings by systematic histopathological can give us a detailed understanding of the tissue microstructure seen in MRI.

Rationale:

Reliable detection of epileptogenic zone (EZ) improves the chance of post-operative seizure freedom in patients with drug-resistant epilepsy. The multi-scale and multi-modal attributions can contribute to our understanding of seizure initiation, propagation, and EZ visibility in pre-operative MRI. Here we report the first steps towards characterizing signature patterns in human epileptogenic tissues by geometric matching of ultrahigh resolution histology and ex vivo MRI from a resected hippocampal tissue.

Methods:

A patient with focal cortical dysplasia was admitted for amygdalohippocampectomy at Kuopio University Hospital. A specimen from hippocampal tissue was scanned on a Bruker 11.7T MR system using a T1w sequence at 55µm3 and cut into 20µm thick coronal sections. Forty-one sections with an effective spacing of 120µm, stained with Nissl to visualize the overall cytoarchitecture, were scanned at 0.1369 µm/pixel. Reconstruction pipeline included sub-sampling of histology images, semi-automated mask creation at 10.95µm, automated alignment through cell bodies stacking, affine registration to ex vivo T1ws through iterated 2D-3D linear and nonlinear transformations, and optical balancing of the MRI-based 3D reconstructed histology volume.

Results:

The runtime for reconstruction pipeline that utilized Bio-Formats, MINC-Toolkit v2, Pearl and C libraries from BigBrain2 pipeline was 3.5 hours on a single CPU. Our volumetric reconstruction of histology at 10.95 µm was remarkable for achieving continuous anatomical microstructures such as the dentate gyrus.

Conclusions:

We developed a pipeline for co-registration and 3D reconstruction of the hippocampus from patients with drug-resistant epilepsy. The unified 3D volume will serve as the reference shape for multi-modal, voxel-based information matching.

Rationale:

Magnetic resonance imaging (MRI) is key for diagnostic of drug-resistant epilepsy patients. However, conventional analysis methods lack specificity to distinguish histopathological changes. Multidimensional diffusion-relaxation correlation MRI (MDDR-MRI) offers a novel analysis framework to disentangle sub-voxel information, providing specificity on cellular changes. In this work, we characterize the diffusion and relaxation properties given by MDDR-MRI at high resolution from two resected hippocampi of focal drug-resistant epilepsy patient.

Methods:

Two patients with focal drug-resistant epilepsy underwent anterior temporal lobectomy, then, we scanned a fraction of the resected hippocampi at isometric 150 µm3 voxel size. We obtained the parameters distributions derived from MDDR-MRI analysis (Diso, DΔ2, R1, R2 and Δω/2πDiso) and performed an analysis on the CA1 and granule cell layer (gcl). According to pathology findings, one hippocampus showed no apparent abnormalities, while the other displayed signs of sclerosis. The MDDR-MRI results were compared with Nissl staining from the same tissue.

Results:

We found that Diso and R1 are higher in the non-sclerotic hippocampus for both CA1 and gcl regions. Meanwhile, DΔ2, R2 and Δω/2πDiso were higher in the sclerotic hippocampus in CA1 and gcl. In Nissl staining we observed a decrease of density in the gcl in the sclerotic hippocampus as well as a reduced cell size in CA1 compared to the non-sclerotic.

Conclusions:

The characterization of the multiple parameters derived from MDDR-MRI on ex vivo resected tissue at ultra-high resolution offers new opportunities to increase specificity during diagnosis and follow-up of drug-resistant epilepsy patients.

Rationale:

Temporal lobe resections from patients with epilepsy provide large amounts of living tissue from the cortex, hippocampus and amygdala. Cultures of these samples over extended period of time as organotypic slice cultures (OCs) can enable measurement of tissue electrophysiological properties over time and a platform for testing different therapeutic approaches. Moreover, OCs can enable investigation of neuronal operational properties using various viral vectors and optogenetic tools.

Methods:

The OCs were cultured as described by Bak et al. 2023 with small modifications. The tissue was sectioned into 250µm slices and cultured on 6-well plate inserts. During the first hours they were stabilized in cell culture media with a cocktail of cytokines, and later transferred to human cerebrospinal fluid. Electrophysiological activity was recorded using a microelectrode array (MEA) system (MultiChannel Systems) and induced with perfusion of 1mM 4-aminopyridine (4-AP) to block voltage-sensitive K+ channels or 200µM N-methyl-D-aspartate to activate NMDA receptors. Adeno-associated virus vectors were used to quantify the viable neurons and specific neuronal types.

Results:

Preliminary analysis showed that after 14 days of culture the slices were viable and exhibited spontaneous firing as well as increased activity upon 4-AP stimulation. Further analysis is needed to verify their seizure-like characteristics.

Conclusions:

The OCs from epilepsy resections have been implemented in our lab successfully. The slices remain alive and electrophysiologically active for at least 14 days. Further examinations with viral vectors and other stimulants are needed to dissect the nature of the signals and make it a robust model of epilepsy.

Rationale:

One third of operated epilepsy patients continue experiencing seizures at long-term follow-up, which indicates the need for a new personalized approach to the treatment. It is known that endocannabinoid systems act as a natural anticonvulsant in in vivo epilepsy models. Therefore, the endocannabinoid enhancement by AKU-005, inhibiting both FAAH and MAGL endocannabinoids degrading enzymes, shows a promising therapeutical application for addressing abnormal neuronal activity and neuroinflammation in the epileptogenic areas.

Methods:

Mice and human epileptic cortex endocannabinoid system was profiled by activity-based protein profiling and mass spectrometry. 4-aminopyridine (4-AP) induced seizure-like activity was recorded in cortical slices by calcium imaging and microelectrode array (MEA). Additionally, the AKU-005 was tested both as acute and prophylactic treatment during MEA recordings.

Results:

Human cortex showed higher MAGL activity over FAAH and comparable levels of the main endocannabinoids. AKU-005 inhibited both enzymes in human cortex, while its specifically inhibited MAGL in mouse cortex. While no basal abnormal network activity was observed, AKU-005 inhibited 4-AP induced hyperexcitability in cultured mice cortical neurons. AKU-005 acute and prophylactic treatment effect on both spiking and local field potential seizure-like network activity was shown in the mice and human cerebral cortex.

Conclusions:

The endocannabinoids degrading enzymes play a role in modulating seizure-like activity in the mouse cortical neurons, and mouse and human cortical slices. AKU-005, as a dual MAGL/FAAH inhibitor, emerges as a promising antiseizure medication, highlighting its potential in ameliorating network hyperexcitability during epileptic seizures.

Rationale:

Epilepsy consists of a heterogeneous group of different neurobiological conditions that significantly increase the risk for epileptic seizures. Comprehensive neurobiological and conceptual basis of epilepsy is still unknown. Oligodendrocytes are one of the main groups of glia-cells in nervous system that are less studied in epilepsy. Identifying new areas of neurobiology that take part in epilepsy could lead to improvements in understanding epilepsy.

Methods:

Systematic literature review was conducted on carefully selected topics on oligodendrocytes with identified new developments, including inhibitory interneuron myelination, satellite oligodendrocytes and oligodendrocyte-inhibitory interneuron interactions in development. A further literature review was conducted to evaluate research on oligodendrocyte involvement in epilepsy. Moreover, utilization of the selected oligodendrocyte subtopics in epilepsy research was assessed.

Results:

Epilepsy search revealed broad unspecific involvement of oligodendrocytes and myelination in wide range epilepsy etiologies. Most recent developments in oligodendrocyte research have not yet been utilized in epilepsy research. Significant proportion of the cortical myelination is found from inhibitory interneuron axons, especially fast-spiking parvalbumin interneurons are myelinated. Satellite oligodendrocytes could have different subtypes and be involved in electrophysiological activity of neurons.

Conclusions:

Identified oligodendrocyte subareas have not been utilized in epilepsy research even tough there is evidence on oligodendrocyte involvement in epilepsy. Oligodendrocyte subareas should be independently studied in greater detail, and most importantly all these new details should be utilized in future epilepsy research

Rationale:

A surge of interest in health and social sciences has been devoted to the study of patients’ involvement in academic research. The literature on ‘patient and public involvement’ (PPI), and other participatory approaches, outline a development in which democratic, inclusive, and ethical relationships in healthcare and health research will replace hierarchical relationships in which patients may be treated as objects rather than subjects. However, a good number of challenges have also been pointed out in relation to PPI, especially concerning the negative effects of problematic power relations.

Methods:

Thematic interviews (n=17) with health and social science researchers included their reflections on their own understanding of PPI, and the current themes and developments concerning PPI in health research more broadly.

Results:

Interpretations on PPI clustered around three themes, each of which included a specific understanding of researcher-patient relationships. The experimenting theme highlighted the potential of change in hierarchical researcher-patient relationships. The practicing theme outlined template-based but flexible relationships, and the walking and wondering theme focused dialogical researcher-patient relationships. Overall, the results illustrate the changing power relations between researchers and patients, ranging from ‘power over’ and ‘power to’ towards ‘power with’.

Conclusions:

Instead of providing evidence that the adoption of PPI would lead to the disappearance of power relations between researchers and patients, our results indicate how power relations change along with the various interpretations of PPI.

Rationale:

Purpose of the research is access to justice and realization of the rights of people with epilepsy. There are 60 000 people living with epilepsy in Finland. People with epilepsy have a lot of problems with realization of legal rights and access to justice. According to the WHO (2022), although the social effects vary from country to country, the stigma and discrimination that surround epilepsy worldwide are often more difficult to overcome than the epileptic seizures themselves. People with epilepsy have legal problems in many areas of life like education, employment, insurance, driving, and typically they meet discrimination.

Methods:

Quantitative survey & qualitative interviews. In the end of year 2022 our research team conducted a survey of realization of the rights for the people with epilepsy (n=237). In the year 2023 we have also conducted interviews (n=38)

Results:

According to the results people with epilepsy have the most problems with healthcare, working life, housing, family and mistreatment. People with epilepsy experience prejudice in all areas of life like in work and study, services both in public sector and private sector, in hobbies and everyday life and also in close relationship. Epilepsy and seizures, stigma, discrimination, legal problems, and quality of life of people with epilepsy are connected to each other.

Conclusions:

More information and communication about epilepsy is needed in society. The work of patient organizations plays a major role in this work. Services of public sector must also be developed.

Rationale:

The Finnish Epilepsy Association (FEA) is a non-profit organisation that provides psychosocial support for people with epilepsy and family members in need. The goal is that individuals contacting our services receive the information and support they need for their daily lives.

Methods:

FEA supports people through phone, chat, email, and social media. FEA professionals systematically categorise contacts according to the discussed topics. In 2023, 768 people contacted FEA’s support channels.

Results:

The majority (47%) of contacts were related to services provided by FEA, such as peer support, courses, and events. Many (34%) wanted to discuss crises, fears, and insecurity caused by epilepsy, as well as treatment pathways and social services. Life changes and evolving epilepsy symptoms require ongoing support, even when time has passed since diagnosis. Issues related to mobility during a driving ban due to epilepsy raised problems in daily life (7%), namely access to work in places without public transport. Other topics (12%) included e.g. concerns about safe housing and employment. According to FEA’s professionals’ assessment, 86% (N=768) of individuals received support for their daily lives through support channels. A sample of contacts (N=78) also assessed the received support. The majority (78%) reported feeling supported, 17% were unsure, and 5% noticed no change.

Conclusions:

FEA’s services complement public services and provide support that no other entity offers to those affected by epilepsy and their families. These services address needs that fall outside the scope of statutory services and are an essential part of effective care in the Finnish epilepsy care pathway.

Rationale:

Infantile seizures cause great concern for both doctors and parents. In addition to modern neuroimaging and genetics, clinical tools helpful in predicting the course of the disease are needed. We prospectively studied epilepsy syndromes with onset before the age 12 months and looked for predictors of outcome by age 24 months.

Methods:

From February 2017 through May 2019, we recruited all eligible infants diagnosed with epilepsy. Data on drug response, electroclinical and etiological studies were gathered prospectively. Structured neurological examination (Hammersmith Infantile Neurological examination [HINE] and Griffiths scales) was given at predetermined intervals until age 24 months when neurocognitive evaluation was performed.

Results:

Included were 60 infants (27 female). The incidence of epilepsy was 131 (95% confidence interval 99-172)/100 000. Epilepsy syndrome was identified in 80% and etiology in 58% of infants. Self-limited infantile epilepsy was the second most common syndrome after infantile epileptic spasms syndrome. PRTT2 was the most common monogenic cause. At age 24 months, 37% of the infants had drug-resistant epilepsy (DRE) and half global developmental delay (GDD). Abnormal first HINE was the most significant predictor of GDD. DRE was associated with structural etiology and GDD. Those with normal first HINE and drug responsiveness had favorable outcome, irrespective if etiology was identified.

Conclusions:

Our results support a high incidence of self-limited epilepsy of infancy and PRRT2 as the genetic cause in the first year of life. Notwithstanding the advances in etiological discovery, we were drawn ‘back to basics’ as standardized neurological examination proved the most valuable tool in prognostication.

Rationale:

Northern epilepsy, epilepsy progressive with mental retardation (EPMR) belongs to neuronal ceroid lipofuscinoses (NCLs), which are a group of lysosomal storage diseases. Characteristics of NCL pathology are autofluorescent aggregates in the central nervous system. EPMR is a late-infantile-onset disease in which patients develop normally until age 5–10 years, when they first present with general tonic–clonic seizures followed by progressive cognitive impairment, resulting in moderate cognitive impairment by adulthood. EPMR is caused by R24G amino acid substitution in CLN8 and belongs to the Finnish Disease Heritage. CLN8 deficiency has been studied traditionally using the motor neuron degeneration (mnd) mouse originating from spontaneous frame shift variant in Cln8. Although mnd mice recapitulate many classic features of NCLs, the phenotype does not fully correspond to those in patients, suggesting that the variant type has a significant impact on the disease progression.

Methods:

We have generated the first CLN8 R24G KI mouse model using CRISPR/Cas9. Preliminary analysis of the mice has been conducted using histopathological, behavioral, and electrophysiological phenotyping.

Results:

CLN8 R24G mice present progressive, intraneural accumulation of autofluorescent material in several regions of the brain and retina. Neuroinflammation markers show clear positive signals already before behavioral changes, which include mild motor impairment and spontaneous seizures.

Conclusions:

CLN8 R24G recapitulates the geno- and phenotype of EMPR more precisely than the mnd mice. We hypothesize that our mouse model will open new possibilities to develop and test targeted treatment options for EPMR and, more broadly, to early-onset neurodegeneration associated with epileptic seizures.

Rationale:

Neuropsychological impairments are common in children with drug-resistant epilepsy. It has been proposed that epilepsy surgery may alleviate these impairments; however, findings from prior studies have not been consistent.

Methods:

We performed a retrospective cohort study of 500 children (248 females) who had undergone epilepsy surgery and neuropsychological assessment. We extracted patient information and neuropsychological functioning – measured using IQ tests and tests of academic attainment – and investigated changes in functioning using regression analyses.

Results:

Children showed declines in all domains of neuropsychological functioning in the time leading up to surgery (all p-values<0.001). At the time of presurgical evaluation, most children (46-60%) scored one or more standard deviations below the mean (0.128). However, children who became seizure-free through surgery showed higher postoperative neuropsychological performance. These children continued to demonstrate improvements in neuropsychological functioning over the course of their long-term follow-up. Children who had discontinued antiseizure medication (ASM) at one-year follow-up showed an eight-to-13-point advantage in postoperative Working Memory, Processing Speed, and Numeracy, and greater improvements in Verbal IQ, Working Memory, Reading, and Spelling (all p-values<0.034) over the postoperative period compared to children who were seizure-free and still receiving ASMs.

Conclusions:

Epilepsy surgery may not only halt but reverse neuropsychological decline in children with drug-resistant epilepsy. To halt this decline as soon as possible, children with focal epilepsy should be considered for epilepsy surgery as early as possible after diagnosis.

Rationale:

Hippocampal excisions obtained during surgical epilepsy treatment can provide valuable information on the underlying electrophysiological mechanisms of the disease and the function of the human hippocampus in general. However, monitoring the network-wide electrophysiological activity of these samples is hindered by most available tools being designed for rodent models in size. We tackled this by creating a microelectrode array (MEA) entitled Hippo-MEA, where the electrode layout is compatible with the dimensions of the adult human hippocampus.

Methods:

The Hippo-MEA has 60 electrodes (⌀ 60 µm) spread out to an area of 5.6 mm x 5.6 mm (electrode pitch 800 µm) and is compatible with 60-electrode headstages from Multichannel Systems (Reutlingen, Germany). The sample chamber is big enough to encompass a whole hippocampal slice. 300 µm thick acute hippocampal slices were obtained from patients undergoing surgery to treat drug-resistant temporal lobe epilepsy. Activity in the slices was induced by perfusing them with the potassium channel blocker 4-aminopyridine (1 mM).

Results:

Preliminary analysis (3 slices from 3 patients) shows that Hippo-MEA detects extracellular action potentials (5 % of electrodes) and local field potentials (gamma-frequency oscillations on 13 % of electrodes). The electrodes were spread wide enough to record different regions of the hippocampus (CA1-4, dentate gyrus).

Conclusions:

The Hippo-MEA is made compatible with a commercially available and widely used headstage and detects electrical activity throughout large samples such as the human hippocampus. The data can potentially be incorporated with ex vivo MRI and histology data voxel-to-voxel to create a multimodal 3D model.