5. Local Somatostatin of the Brain, an Agent in the Genesis of Focal Epilepsy?

2015 ◽  
pp. 30-31
Author(s):  
E. Elomaa ◽  
R. Lehtovaara ◽  
G. Johansson ◽  
L. Kukkola
Keyword(s):  
Focal Epilepsy ◽  
The Brain

Classification of seizures and epilepsy

2019 ◽  
pp. 935-944
Author(s):  
Andrew McEvoy ◽  
Tim Wehner ◽  
Victoria Wykes
Keyword(s):  
Focal Epilepsy ◽  
Focal Cortical Dysplasia ◽  
Hippocampal Sclerosis ◽  
Epileptic Seizures ◽  
Recurrence Risk ◽  
Medical Emergency ◽  
Unprovoked Seizure ◽  
Generalized Seizures ◽  
The Brain

Epileptic seizures are transient neurologic alterations due to abnormal excessive or synchronous neuronal cerebral activity. They may cause subjective symptoms (aura), and objective autonomic, behavioural, or cognitive alterations in any combination. Focal seizures are initially generated in one circumscribed area in the brain, whereas generalized seizures involve bihemispheric neuronal networks from the seizure onset. Epilepsy is a brain disease defined by the occurrence of two unprovoked seizures more than 24 h apart or one unprovoked seizure with underlying pathological or genetic factors resulting in a similar recurrence risk. Focal epilepsy syndromes are best classified by aetiology or anatomical area of origin. A seizure that does not self-terminate results in status epilepticus, and constitutes a medical emergency that requires immediate treatment. Focal cortical dysplasia and hippocampal sclerosis are the commonest aetiologies of epilepsy amenable to surgical treatment and are reviewed here. The limbic pathway may be involved in seizure propagation, and the anatomy is described.

scholarly journals P.048 Characterization of somatic mutations in mTOR pathway genes in focal cortical dysplasias

2019 ◽  
Vol 46 (s1) ◽  
pp. S26-S27
Author(s):  
E Krochmalnek ◽  
A Accogli ◽  
J St-Onge ◽  
N Addour ◽  
R Dudley ◽  
...  
Keyword(s):  
Somatic Mutations ◽  
Focal Epilepsy ◽  
Mtor Pathway ◽  
High Yield ◽  
Structural Abnormalities ◽  
Causal Variants ◽  
Cortical Dysplasias ◽  
Custom Panel ◽  
The Brain

Background: Focal cortical dysplasias (FCDs) are congenital structural abnormalities of the brain, and represent the most common cause of medication-resistant focal epilepsy in children and adults. Recent studies have shown that somatic mutations (i.e. mutations arising in the embryo) in mTOR pathway genes underlie some FCD cases. Specific therapies targeting the mTOR pathway are available. However, testing for somatic mTOR pathway mutations in FCD tissue is not performed on a clinical basis, and the contribution of such mutations to the pathogenesis of FCD remains unknown. Aim: To investigate the feasibility of screening for somatic mutations in resected FCD tissue and determine the proportion and spatial distribution of FCDs which are due to low-level somatic mTOR pathway mutations. Methods: We performed ultra-deep sequencing of 13 mTOR pathway genes using a custom HaloPlexHS target enrichment kit (Agilent Technologies) in 16 resected histologically-confirmed FCD specimens. Results: We identified causal variants in 62.5% (10/16) of patients at an alternate allele frequency of 0.75–33.7%. The spatial mutation frequency correlated with the FCD lesion’s size and severity. Conclusions: Screening FCD tissue using a custom panel results in a high yield, and should be considered clinically given the important potential implications regarding surgical resection, medical management and genetic counselling.

scholarly journals Drug-resistant focal epilepsy in children is associated with increased modal controllability of the whole brain and epileptogenic regions

2021 ◽  
Author(s):  
Kiran Seunarine ◽  
Xiaosong He ◽  
Martin Tisdall ◽  
Christopher Clark ◽  
Danielle S Bassett ◽  
...  
Keyword(s):  
Diffusion Mri ◽  
Focal Epilepsy ◽  
Brain Network ◽  
Structure And Function ◽  
Network Control ◽  
Drug Resistant ◽  
Drug Resistant Epilepsy ◽  
And Function ◽  
The Brain ◽  
Disease Understanding

Network control theory provides a framework by which neurophysiological dynamics of the brain can be modelled as a function of the structural connectome constructed from diffusion MRI. Average controllability describes the ability of a region to drive the brain to easy-to-reach neurophysiological states whilst modal controllability describes the ability of a region to drive the brain to difficult-to-reach states. In this study, we identify increases in mean average and modal controllability in children with drug-resistant epilepsy compared to healthy controls. Using simulations, we purport that these changes may be a result of increased thalamocortical connectivity. At the node level, we demonstrate decreased modal controllability in the thalamus and posterior cingulate regions. In those undergoing resective surgery, we also demonstrate increased modal controllability of the resected parcels, a finding specific to patients who were rendered seizure free following surgery. Changes in controllability are a manifestation of brain network dysfunction in epilepsy and may be a useful construct to understand the pathophysiology of this archetypical network disease. Understanding the mechanisms underlying these controllability changes may also facilitate the design of network-focussed interventions that seek to normalise network structure and function.

Long-term brain network reorganization predicts responsive neurostimulation outcomes for focal epilepsy

2021 ◽  
Vol 13 (608) ◽  
pp. eabf6588
Author(s):  
Ankit N. Khambhati ◽  
Alia Shafi ◽  
Vikram R. Rao ◽  
Edward F. Chang
Keyword(s):  
Therapeutic Response ◽  
Focal Epilepsy ◽  
Therapeutic Benefit ◽  
Brain Network ◽  
First Year ◽  
Seizure Reduction ◽  
Neural Recordings ◽  
Brain Network Reorganization ◽  
The Brain

Responsive neurostimulation (RNS) devices, able to detect imminent seizures and to rapidly deliver electrical stimulation to the brain, are effective in reducing seizures in some patients with focal epilepsy. However, therapeutic response to RNS is often slow, is highly variable, and defies prognostication based on clinical factors. A prevailing view holds that RNS efficacy is primarily mediated by acute seizure termination; yet, stimulations greatly outnumber seizures and occur mostly in the interictal state, suggesting chronic modulation of brain networks that generate seizures. Here, using years-long intracranial neural recordings collected during RNS therapy, we found that patients with the greatest therapeutic benefit undergo progressive, frequency-dependent reorganization of interictal functional connectivity. The extent of this reorganization scales directly with seizure reduction and emerges within the first year of RNS treatment, enabling potential early prediction of therapeutic response. Our findings reveal a mechanism for RNS that involves network plasticity and may inform development of next-generation devices for epilepsy.

The birth of experimental neurosurgery: Wilder Penfield at Montreal’s Royal Victoria Hospital, 1928–1934

2021 ◽  
pp. 1-8
Author(s):  
Richard Leblanc
Keyword(s):  
Royal Victoria Hospital ◽  
Focal Epilepsy ◽  
Spinal Nerve ◽  
Scientific Discipline ◽  
Posttraumatic Epilepsy ◽  
Health And Disease ◽  
Function Relationship ◽  
Del Rio ◽  
Relationship Of ◽  
The Brain

Wilder Penfield is well known as the founder of the Montreal Neurological Institute (MNI), the site of his most important contributions to the investigation and treatment of epilepsy and to our understanding of the structure-function relationship of the brain. The seeds of the MNI were sown 6 years before its opening in 1934, when Penfield accepted the position of head of the Subdepartment of Neurosurgery at McGill University’s Royal Victoria Hospital (RVH). Penfield took this position because of the facilities made available to him to pursue the neuropathological research that he had undertaken with Pío del Río Hortega in Madrid, and to continue his investigation into the nature and treatment of posttraumatic epilepsy that he began with Otfrid Foerster in Breslau. Penfield and his first neurosurgical research fellows Joseph Evans, Jerzy Choróbski, Nathan Norcross, Theodore Erickson, Isadore Tarlov, and Arne Torkildsen studied the substrate of focal epilepsy, the innervation of cortical arteries, the function of the diencephalon, the microscopic structure of spinal nerve roots, and the ventricular system in health and disease. In his 6 years at the RVH, Penfield and his fellows effected a paradigm shift that saw neurosurgery pass from empirical practice to scientific discipline.

076 The expanding clinical phenotype of NMDAR encephalitis

2018 ◽  
Vol 89 (6) ◽  
pp. A31.1-A31
Author(s):  
Jessica Qiu ◽  
Jacob Helou ◽  
Nicholas Urriola ◽  
Miriam Welgampola ◽  
John Parratt ◽  
...  
Keyword(s):  
Psychiatric Symptoms ◽  
Focal Epilepsy ◽  
Insular Cortex ◽  
Ovarian Teratoma ◽  
Downbeat Nystagmus ◽  
Progressive Dementia ◽  
Epilepsia Partialis Continua ◽  
Truncal Ataxia ◽  
The Right ◽  
The Brain

IntroductionThe classic phenotype of anti-N-methyl-d-aspartate receptor (NMDA-R) encephalitis is a constellation of prodromal psychiatric symptoms, seizures, movement disorder and progressive autonomic dysfunction, frequently associated with ovarian teratoma. We describe four cases illustrating the expanding phenotype of NMDA-R encephalitis. We present two cases from two tertiary hospitalsCase 1 A 31 year old woman presented with focal onset seizures. She developed epilepsia partialis continua. CSF and serum NMDA-R antibodies were detected and PET of the brain showed bi-frontal hyper-metabolism. The seizures resolved with immunotherapy.Case 2 A 26 year old woman presented with vomiting and dysequilibrium. She was found to have torsional downbeat nystagmus with otherwise normal eye movements and vestibulo-ocular reflexes. She developed bilateral appendicular and truncal ataxia, head bobbing and ocular flutter. PET demonstrated diffuse cerebellar hyper-metabolism. CSF NMDA-R antibodies were detected and an ovarian teratoma was identified.Case 3 A 67 year old right-handed woman was treated for HSV encephalitis. MRI of the brain demonstrated typical changes in the right anteromedial temporal lobe, inferior frontal lobe and insular cortex. Five months later, she deteriorated with progressive cognitive dysfunction and prominent orofacial dyskinesia. Initially both CSF and serum were negative for NMDAR antibodies, but repeat CSF and serum were positive.Case 4 A 61 year old woman presented with progressive cognitive impairment over eight months initially characterised by difficulty with calculations and making mistakes at work but subsequent severe impairment of language, executive function and memory and the development of facile and disinhibited behaviour. PET demonstrated mesial bi-temporal hyopo-metabolism and NMDA-R antibodies were detected in serum. She recovered with immunotherapy.ConclusionNMDA-R encephalitis should be considered in various neurological presentations including explosive onset focal epilepsy, rapidly progressive dementia, post HSV encephalitis and rhombencephalitis. Early detection is important given the frequent response to immunotherapy.

scholarly journals Changes in subjective experience elicited by direct stimulation of the human orbitofrontal cortex

Neurology ◽  
2018 ◽  
Vol 91 (16) ◽  
pp. e1519-e1527 ◽  
Author(s):  
Kieran C. R. Fox ◽  
Jennifer Yih ◽  
Omri Raccah ◽  
Shrita L. Pendekanti ◽  
Lauren E. Limbach ◽  
...  
Keyword(s):  
Orbitofrontal Cortex ◽  
Subjective Experience ◽  
Focal Epilepsy ◽  
Causal Link ◽  
Direct Stimulation ◽  
Sensory Experiences ◽  
Neurosurgical Patients ◽  
Intracranial Electrodes ◽  
The Brain ◽  
Stimulation Of

ObjectiveWe applied direct cortical stimulation (DCS) to the orbitofrontal cortex (OFC) in neurosurgical patients implanted with intracranial electrodes to probe, with high anatomic precision, the causal link between the OFC and human subjective experience.MethodsWe administered 272 instances of DCS at 172 OFC sites in 22 patients with intractable focal epilepsy (from 2011 to 2017), none of whom had seizures originating from the OFC.ResultsOur observations revealed a rich variety of affective, olfactory, gustatory, and somatosensory changes in the subjective domain. Elicited experiences were largely neutral or negatively valenced (e.g., aversive smells and tastes, sadness, and anger). Evidence was found for preferential left lateralization of negatively valenced experiences and strong right lateralization of neutral effects. Moreover, most of the elicited effects were observed after stimulation of OFC tissue around the transverse orbital sulcus, and none were seen in the most anterior aspects of the OFC.ConclusionsOur study yielded 3 central findings: first, a dissociation between the “silent” anterior and nonsilent middle/posterior OFC where stimulation clearly elicits changes in subjective experience; second, evidence that the OFC might play a causal role in integrating affect and multimodal sensory experiences; and third, clear evidence for left lateralization of negatively valenced effects. Our findings provide important information for clinicians treating OFC injury or planning OFC resection and scientists seeking to understand the brain basis for the integration of sensation, cognition, and affect.

COMPUTATIONAL MODELING OF TRANSCRANIAL DIRECT CURRENT STIMULATION IN THE CHILD BRAIN: IMPLICATIONS FOR THE TREATMENT OF REFRACTORY CHILDHOOD FOCAL EPILEPSY

2014 ◽  
Vol 24 (02) ◽  
pp. 1430006 ◽  
Author(s):  
MARTA PARAZZINI ◽  
SERENA FIOCCHI ◽  
ILARIA LIORNI ◽  
ALBERTO PRIORI ◽  
PAOLO RAVAZZANI
Keyword(s):  
Electric Field ◽  
Computational Modeling ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Focal Epilepsy ◽  
Brain Area ◽  
Epileptiform Activity ◽  
Brain Regions ◽  
Direct Current Stimulation ◽  
The Brain

Transcranial direct current stimulation (tDCS) was recently proposed for the treatment of epilepsy. However, the electrode arrangement for this case is debated. This paper analyzes the influence of the position of the anodal electrode on the electric field in the brain. The simulation shows that moving the anode from scalp to shoulder does influence the electric field not only in the cortex, but also in deeper brain regions. The electric field decreases dramatically in the brain area without epileptiform activity.

scholarly journals Critical slowing as a biomarker for seizure susceptibility

2019 ◽  
Author(s):  
Matias I. Maturana ◽  
Christian Meisel ◽  
Katrina Dell ◽  
Philippa J. Karoly ◽  
Wendyl D’Souza ◽  
...  
Keyword(s):  
Focal Epilepsy ◽  
Warning Signal ◽  
Theoretical Models ◽  
Critical Transitions ◽  
Epileptiform Discharges ◽  
Brain Signals ◽  
Change State ◽  
Intracranial Electroencephalography ◽  
The Brain

AbstractThe human brain has the capacity to rapidly change state, and in epilepsy these state changes can be catastrophic, resulting in loss of consciousness, injury and even death. Theoretical interpretations considering the brain as a dynamical system would suggest that prior to a seizure recorded brain signals may exhibit critical slowing, a warning signal preceding many critical transitions in dynamical systems. Using long-term intracranial electroencephalography (iEEG) recordings from fourteen patients with focal epilepsy, we found key signatures of critical slowing prior to seizures. Signals related to a critically slowing process fluctuated over temporally long scales (hours to days), longer than would be detectable in standard clinical evaluation settings. Seizure risk was associated with a combination of these signals together with epileptiform discharges. These results provide strong validation of theoretical models and demonstrate that critical slowing is a reliable indicator that could be used in seizure forecasting algorithms.

scholarly journals EXPERIENCE OF THE MANAGEMENT OF PATIENTS WITH ONCOGENIC EPILEPSIA

2017 ◽  
Vol 22 (6) ◽  
pp. 316-321
Author(s):  
Diana V. Dmitrenko ◽  
N. A Shnayder ◽  
Yu. A Dykhno ◽  
A. I Dmitrenko ◽  
I. G Strotskaya
Keyword(s):  
Primary Care Physicians ◽  
High Field ◽  
Focal Epilepsy ◽  
Epileptic Seizures ◽  
Time Interval ◽  
Common Symptom ◽  
Childbearing Age ◽  
High Field Mri ◽  
Postoperative Changes ◽  
The Brain

Epileptic seizures are a common symptom in brain tumor patients. The aim of the study: to investigate the features of oncogenic epilepsy in women of the fertile age. Material and methods. The study included 352 women aged of from 15 to 49 years, suffering from epilepsy. The examination consisted of an EEG and a high-field MRI investigation of the brain (1.5 Tc) with a scan interval of 1-2 mm. Results and discussion. Epilepsy against the background of volumetric brain formations was found in 15/139 (10.8%) patients with symptomatic focal epilepsy. The age of a debut of oncogenic epilepsy ranged from 2 to 38 years, the median was 14 years. Astrocytomas, found in 40% of cases, prevailed in the etiology of volumetric formations. A considerable time interval between the epileptic seizure debut and the high-field MRI examination was noted to result in the diagnosis of volumetric brain formation: median was 10.5 [2; 15] years. In the clinical picture of epilepsy there were dominated simple and complex focal seizures. Secondary-generalized tonic-clonic seizures were stopped in 60% of cases. The pharmacoinduced remission of oncogenic epilepsy was achieved in 3/15 (20%) cases. Conclusion. The low alertness of primary care physicians in terms of diagnosis of neuroncology in women of childbearing age was noted. The therapy of symptomatic oncogenic epilepsy was characterized by certain difficulties, caused by the growth of volume formation and/or gross cicatricial postoperative changes in the brain substance.

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