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Susanne Fauser,
Charles Essang,
Dirk Matthias Altenmüller,
Anke Staack,
Bernhard J Steinhoff,
Karl Strobl,
Thomas Bast,
Susanne Schubert-Bast,
Soroush Doostkam,
Josef Zentner,
Andreas Schulze-Bonhage
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ABSTRACT: PURPOSE: The new International League Against Epilepsy (ILAE) classification for focal cortical dysplasia (FCD) differentiates between patients with isolated FCD (type 1) and FCD with an associated hippocampal sclerosis (HS) (type 3a). In contrast to the former FCD classification by Palmini, which considered only histologic features, the novel ILAE classification also relies on magnetic resonance imaging (MRI) findings and presumed pathogenesis. We investigated in a cohort of 100 patients with exclusively temporal FCD if the new subdivision of FCD is reflected in clinical characteristics. METHODS: Thirty-one patients with FCD type 1 and 50 patients with FCD type 3a in the temporal lobe were included. In all patients MRI and histology of the FCD were available. Both patient groups were compared to 19 patients with temporal FCD type 2 with clearly different histologic appearance. KEY FINDINGS: Patients with FCD type 1 and type 3a presented with similar clinical features in many respects. In univariate analyses, no statistically significant differences were found as to age at epilepsy onset (p = 0.07) and epilepsy surgery (p = 0.14), a normal appearing neocortical temporal lobe (p = 0.08) or diagnosis of FCD by visual inspection of MRI (p = 0.08), preoperative seizure frequency (p = 0.06), and the predominance of an epigastric aura (p = 0.08). The postoperative outcome was nearly identical 1 year (p = 0.8) and 2 (p = 0.8), 3 (p = 0.8), 5 (p = 0.7), and 8 (p = 1.0) years postoperatively. Only febrile seizures (p = 0.025) and an aura (p = 0.03) were significantly more frequently reported in patients with FCD type 3a. Similar results were obtained from a multivariate logistic regression analysis. Patients with FCD type 2 were more different: Compared to FCD type 3a, age at epilepsy surgery was significantly lower (p = 0.004) and auras (p = 0.005) were significantly less frequently reported. Epigastric auras (p = 0.04) and febrile seizures (p = 0.025) occurred significantly less frequently in patients with FCD type 2 without HS compared to FCD type 3a. The diagnosis of an FCD was significantly more frequently made (p = 0.03) by visual inspection of the MRI compared to FCD type 1. SIGNIFICANCE: Clinical features did not allow to clear separation of temporal FCD types 1 and 3a. Statistically significant differences were seen in a history of febrile seizures and the occurrence of auras more common in FCD type 3a. However, FCD type 2 in the same localization but with different histology presented with further differences such as more frequent FCD diagnosis by visual inspection of MRI, earlier operation, and less frequent epigastric auras.
Epilepsia 03/2013; · 3.96 Impact Factor
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Anke M Staack,
Anne-Sophie Wendling,
Julia Scholly,
Ilona Wisniewski,
Christoph Kurth,
Josef Saar,
Karin Mathews,
Frédéric Bodin, Susanne Fauser,
Dirk-Matthias Altenmüller,
Thomas M Freiman,
Andreas Schulze-Bonhage,
Josef Zentner,
Gerhard Reinshagen,
Bernhard J Steinhoff
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ABSTRACT: PURPOSE: Resective epilepsy surgery is the recommended treatment for a well-defined group of patients with drug-resistant epilepsy. Long-term outcome studies are an appropriate quality control to assess the value of elective surgical procedures ethically and economically. This paper reports the long-term post-surgical follow-up of adult patients of the Kork Epilepsy Centre. METHOD: Data collection was performed by means of a questionnaire to obtain updated information about postsurgical outcome, frequency and postsurgical seizure semiology in case of relapse, postsurgical use of antiepileptic drugs, social issues and satisfaction rates. We classified seizure outcome according to the ILAE surgery outcome scale (OC 1-OC 6). RESULTS: Outcome data of 340 adult patients were obtained. Mean post-operative follow-up was 6.7 years (range 1.0-21.6 years). Seizure remission was 67% if comprising patients with postoperative auras only (OC 1+OC 2). Sixty-two per cent of patients were completely seizure free. The majority of patients (78%) underwent temporal lobe resections. Sixty-four per cent of these and 52% of the patients with extra-temporal resections became completely seizure-free (OC 1). Only 34% of the patients with negative MRI achieved complete seizure-freedom. CONCLUSION: In line with others our huge cohort sample that covers decades of experience with epilepsy surgery revealed satisfying long-term outcome results. Best results were obtained in lesional temporal lobe epilepsy, least favourable results in MRI-negative epilepsy.
Seizure 02/2013; · 1.80 Impact Factor
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ABSTRACT: Approximately one third of epilepsy patients are not adequately treatable by antiepileptic medication. Curative resective epilepsy surgery can be performed in only a subgroup of these pharmacoresistent patients in whom the epileptogenic focus is localizable and does not overlap with eloquent brain areas. To the remaining patients (with bilateral or multiple epileptogenic foci, with epilepsy onset in eloquent areas, or with no identifiable epileptogenic focus) palliative epilepsy surgery can be offered if they suffer from disabling seizures. Standard palliative procedures currently comprise corpus callosotomy, multiple subpial transections, and vagus nerve stimulation. New approaches such as focus distant deep brain stimulation or direct stimulation of the hippocampus have gained the most interest. Feasibility studies, small pilot studies, and, recently, larger multicenter trials showed that direct brain stimulation shall be considered a potential helpful procedure in the field of palliative surgery. Moreover, with the increasing use of stereo-EEG in invasive video-EEG monitoring, stereo-EEG-guided thermocoagulation has the potential for a promising new treatment option in patients not amenable to resective epilepsy surgery. There is no general consensus on which palliative procedure is most effective in patients with difficult-to-treat epilepsy syndromes. The decision must be based on individual factors of a given patient. This review summarizes experience with palliative approaches collected in adult and pediatric patient series over the past decades and may help to thoroughly balance beneficial effects and risks of each procedure.
Advances and technical standards in neurosurgery 01/2012; 39:165-94.
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ABSTRACT: Characterization of seizure semiology in patients with hypothalamic hamartoma (HH) based on video-electroencephalography (EEG) monitoring (VEM).
We retrospectively analyzed seizure semiology of 31 patients (20 male, mean age 23.5 years) who underwent VEM at the University Hospitals Freiburg or Heidelberg, Germany. Inclusion criteria were magnetic resonance evidence of an HH, no prior surgical or radiosurgical treatment, and at least two video-documented seizures. A total of 263 seizures were included (mean number of seizures/patient 8.5, range 2-10). To analyze age-dependent changes in seizure semiology, patients were grouped into "children" (3-11 years, n = 5), "adolescents" (12-17 years, n = 4), and "adults" (≥18 years, n = 22).
According to patient history, gelastic seizures had occurred in all patients, in 74% as the initial seizure type at epilepsy onset. In VEM, epileptic laughter varied from facial grinning to intense contractions of the diaphragm and body shaking. Unilateral motor signs were seen ipsi- and contralaterally to the HH. Tonic seizures were frequent and did not depend on the state of vigilance. Children, in contrast to adults and adolescents, did not show secondarily generalized tonic-clonic seizures, the gelastic component was the dominating and initial semiologic element, and seizures were significantly shorter.
Seizure semiology is highly variable and age dependent. This may reflect network modulations with different propagation of ictal activity and/or secondary epileptogenesis. Detailed knowledge about such changes may contribute to both earlier recognition of seizures during childhood and better assignment of seizure types to a hypothalamic origin.
Epilepsia 10/2010; 51(10):2116-23. · 3.96 Impact Factor
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ABSTRACT: Focal cortical dysplasia (FCD) type II is an important cause of drug-resistant epilepsy. Clinical presentation is variable, and depends on age of onset of seizures and the location and size of lesion. As FCD type II cannot be diagnosed with certainty in the clinic, in vivo identification by use of MRI is important. Diagnosis will have a major effect on management of this pathology as it should prompt referral for specialist assessment. Drug treatment commonly proves ineffective, whereas appropriate surgical treatment can be curative in many cases. The dramatic cellular anomalies of FCD seen at histopathology indicate a widespread pattern of molecular disruption underpinning the structural disorganisation of the cortex. The cause for FCD has not been firmly established, and there are no explanations for its potent intrinsic ability to cause seizures. There seem to be both neurodevelopmental abnormalities and possible premature neurodegeneration in FCD. Understanding the coordination of the abnormal processes in FCD type II might help to promote improved detection in vivo, direct treatment strategies, and perhaps help explain the development, differentiation, and loss of brain cells, with broad implications for the epilepsies and other neurological disorders.
The Lancet Neurology 10/2009; 8(9):830-43. · 23.46 Impact Factor
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Susanne Fauser,
Sanjay M Sisodiya,
Lillian Martinian,
Maria Thom,
Christoph Gumbinger,
Hans-Jürgen Huppertz,
Claudia Hader,
Karl Strobl,
Bernhard J Steinhoff,
Marco Prinz,
Josef Zentner,
Andreas Schulze-Bonhage
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ABSTRACT: This study describes the existence and the clinical and electrophysiological features of multi-focal cortical dysplasia in epilepsy patients. Five patients with intractable focal epilepsy are reported. All patients underwent invasive presurgical video-electroencephalography monitoring. Localization of dysplastic areas was based on high-resolution magnetic resonance scanning, surface and intracranial electroencephalography. Four patients underwent epilepsy surgery. Histological findings in focal cortical dysplasia (FCD) were classified according to Palmini. In addition, genetic examinations were performed in order to assess possible mutations in the genes for tuberous sclerosis complex. In four patients, FCDs were located in the same hemisphere. One case presented with bilateral FCDs. In three patients seizures arose from two separate dysplastic areas and in one patient, one lesion showed only interictal activity. In one further patient, seizures started exclusively from the hippocampus. In two of three patients with removal of the FCDs, the histological subtype was identical (Palmini type 2) and in one patient, histology differed between the lesions. All operated patients became seizure-free. In patients with FCD type 2, germ-line mutations in the tuberous sclerosis complex genes were not detectable. Dysplastic brain regions may not be restricted to a single brain region. Areas of FCD can have different degrees of epileptogenicity, ranging from electrographic silence to interictal epileptic discharges and initial involvement in seizure generation. Based on genetic analysis and clinical features, multi-FCD in this patient series was not likely to be related to tuberous sclerosis.
Brain 07/2009; 132(Pt 8):2079-90. · 9.46 Impact Factor
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ABSTRACT: Focal cortical dysplasia (FCD) is a common cause of pharmacoresistant human epilepsy. FCD has frequently been discussed as a "forme fruste" of tuberous sclerosis complex (TSC) because of the radiologic and histologic resemblance of dysplastic areas to tubers in TSC. Mutations or a germ-line predisposition in terms of increased polymorphisms in the TSC genes have been presumed to influence the pathogenesis of FCD. A detailed genotype-phenotype analysis of these patients has not been performed so far.
In this study, 33 patients with FCD (among them 23 with FCD type 2 and 4 patients with multifocal FCD) were investigated (1) clinically as to dermatologic manifestations, retinal hamartoma, cardial rhabdomyoma, and renal angiomyolipoma, and (2) genetically by considering lesional brain tissue and blood using single strand conformation polymorphism (SSCP) electrophoresis and sequencing of the TSC1 and TSC2 genes.
In the clinical examinations, no subtle features of TSC could be detected in this large group of patients with FCD, pointing to the fact that this is a different patient group without clinical overlap. Several sequence alterations were found in the TSC1 and TSC2 genes in both lesional brain tissue and blood of FCD patients, however, in similar frequencies to that of the normal population. Moreover, most of these sequence alterations were silent.
This study shows that FCD-even multifocal FCD-is not caused by mutations in the TSC genes and seems not to be promoted by polymorphisms in the TSC genes. Therefore, FCD cannot be regarded as a "forme fruste" of TSC.
Epilepsia 02/2009; 50(6):1396-408. · 3.96 Impact Factor
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ABSTRACT: Latencies between seizure onset, propagation of ictal activity, and initial clinical symptoms and signs are critically important for the successful implementation of detection-based intervention systems in the treatment of epilepsy. This study analyzes intracranial EEG-recordings for temporal characteristics of ictal spread and its dependence on focus localization.
Intracerebral EEG recordings of 215 seizures from 43 patients with pharmacoresistant focal epilepsy were evaluated based on site of first propagation, latencies between EEG seizure onset, early propagation, and clinical seizure onset. Seizure onset was mesial temporal in 15 patients, neocortical temporal in 15 patients, and frontal in 13 patients.
Periods during which ictal activity remained confined to the seizure onset area showed significant differences between the patient groups. Median latencies between electrographic seizure onset and early propagation were significantly longer for patients with mesial temporal (5 s in seizure-based analysis/10 s in patient-based analysis) as compared to neocortical temporal (3 s/5 s) and frontal seizure focus (1 s/2 s; p < 0.01). Concordantly, median latencies to onset of clinical symptomatology were significantly longer for patients with mesial temporal (17 s/19 s) as compared to neocortical temporal (11 s/17 s) and frontal seizure focus (4 s in seizure-based analysis and 6 s in patient-based analysis; p < 0.01).
The speed of propagation of ictal activity and the latencies until initial clinical seizure symptoms differ significantly depending on focus localization. Extended spread often occurred within the time window during which current detection systems operate. This suggests that inclusion criteria of patients suitable for testing the efficacy of detection-based seizure intervention strategies should be based on focus localization and patient-individual propagation patterns.
Epilepsia 04/2008; 49(9):1594-601. · 3.96 Impact Factor
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ABSTRACT: Interictal activity from epileptic foci may have remote effects as demonstrable by assessing brain perfusion, metabolism and excitability. So far, the effect of surgical removal of the epileptic focus on cortical networks has only rarely been addressed. This study aims at an assessment of changes in intracortical inhibition and excitability in patients undergoing successful epilepsy surgery. Twenty-two patients (12 females, 10 males, mean age 37.8 years) with identical pre- and postsurgical antiepileptic medication were investigated using focal transcranial magnetic stimulation. Motor thresholds (MT), contralateral cortical silent periods (CSP) and amplitudes of motor evoked potentials (MEP) using paired pulse paradigms were investigated both, at the focal and non-focal hemisphere before and at least 3 months after successful epilepsy surgery. The postsurgical mean MT when stimulating at the focal hemisphere was significantly higher than at the non-focal hemisphere (p=0.01). Postsurgically, the mean duration of the CSP at 120% and at 150% of MT of the non-focal hemisphere was significantly shorter than presurgically (p=0.04), and the mean MEP amplitude following paired-pulse stimulation with an interstimulus interval of 10 ms of the non-focal hemisphere was significantly lower than presurgically (p=0.03). In summary, both parameters representing inhibition and facilitation changed following epilepsy surgery; effects were statistically significant on the non-focal hemisphere. Transcranial magnetic stimulation thus gave evidence of remote effects of an epileptic focus and its surgical removal. Extended changes in excitability due to the presence or absence of an epileptic focus may be related to widespread functional impairments in patients with focal epilepsy.
Epilepsy Research 04/2008; 79(1):55-62. · 2.29 Impact Factor
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ABSTRACT: Source localization using single current dipoles estimates equivalent centers of the spiking gray matter. The extent of the active cortex, however, is difficult to assess from scalp EEG because of the unknown individual volume conduction. The spatial scatter of dipole localizations of single spikes has been proposed as a measure of extent. Single spike localization, however, is strongly dependent on the signal-to-noise ratio (SNR), that is, the ratio of spike and background EEG amplitudes. On the other hand, averaging of all spikes yields only the localization of equivalent centers of activity. We investigated the influence of SNR and multiple subaverages on the estimation of spatial extent by comparing the localization scatter of 100 single spikes in 27 spike types of 25 epilepsy patients with 1000 different subaverages computed by random sampling and bootstrapping. Averaging increased SNR and therefore allowed for localization not only at the spike peak but also during spike onset when less cortex is active. In several subjects with known cortical lesions, the single spike scatter considerably exceeded the lesion. Single dipole scatter was highly correlated with SNR (r = -0.83, P < 0.0001) and was greatly reduced when analyzing multiple subaverages of 10, 25, 50, and 100 spikes. Thus, we found a dominant role of the SNR on the estimated extent and improvement by scatterplots based on the dipole localization of randomly sampled subaverages.
Journal of Clinical Neurophysiology 01/2007; 23(6):487-97. · 1.45 Impact Factor
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Susanne Fauser,
Hans-Juergen Huppertz,
Thomas Bast,
Karl Strobl,
Georgios Pantazis,
Dirk-Matthias Altenmueller,
Bertram Feil,
Sabine Rona,
Christoph Kurth,
Dietz Rating,
Rudolf Korinthenberg,
Bernhard J Steinhoff,
Benedikt Volk,
Andreas Schulze-Bonhage
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ABSTRACT: Focal cortical dysplasias (FCDs) are increasingly diagnosed as a cause of symptomatic focal epilepsy in paediatric and adult patients. However, little is known about the clinical characteristics of epilepsy in these patients. In order to elucidate the clinical characteristics of their epilepsy, 120 pharmacoresistant patients including children and adults with histologically proven FCD were studied retrospectively. Age at seizure onset was analysed in the total group and compared between subgroups with different localization and different histological subtypes of FCD. The role of febrile seizures with respect to dual pathology was investigated. Seizure semiology was analysed focusing on initial seizure type and change of seizure semiology during the course of disease. Finally, transient responsiveness to antiepileptic drug therapy was studied. In the majority of patients, epilepsy began in the first 5 years of life. However, onset of epilepsy could also occur in the second or third decade until the age of 60. Age at epilepsy onset was not significantly different between temporal, extratemporal and multilobar localization of FCD. Patients without cytoarchitectural abnormalities (mild malformations of cortical development, FCD 1a according to Palmini) had significantly later epilepsy onset (P= 0.001) compared with patients with cytoarchitectural abnormalities (FCD 1b, 2a and 2b according to Palmini). In patients with additional hippocampal sclerosis (dual pathology) febrile seizures were significantly more frequently reported (P = 0.02) than in patients without dual pathology. Moreover, patients with dual pathology and febrile seizures significantly more frequently presented with severe hippocampal sclerosis (Wyler Grade 3-4) as compared with patients with dual pathology in the absence of febrile seizures (P = 0.03). First observed seizures were mainly tonic or generalized tonic-clonic. A change of seizure semiology seemed to be age-dependent and occurred between the age of >1 and 14 years. About 15.8% of the patients presented with status epilepticus during the course of disease. About 17% of the patients showed transient responsiveness (> or =1 year seizure freedom) to antiepileptic drug therapy either after initial therapy (50%) or later in the course of epilepsy (50%). Patients with FCD represent a heterogeneous group. Different age at epilepsy onset and transient responsiveness to antiepileptic drugs in approximately 17% of patients may reflect different dynamics in epileptogenicity of the underlying FCD. Dual pathology may be associated with different pathomechanisms in patients with and without febrile seizures.
Brain 07/2006; 129(Pt 7):1907-16. · 9.46 Impact Factor
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ABSTRACT: Hippocampal sclerosis is often associated with macroscopic or microscopic dysplasia in the temporal neocortex (TN). The relevance of such a dual pathology with regard to epileptogenesis is unclear. This study investigates the role of both pathologies in the generation of ictal and interictal activity. Ictal (113 seizures) and interictal data from invasive EEG recordings with simultaneous depth electrodes in the hippocampus and subdural electrodes over the TN were analysed retrospectively in 12 patients with variable degrees of hippocampal sclerosis and different types of histologically confirmed temporal cortical dysplasia [all male, age at epilepsy onset <1-29 years (mean 9.6 years), age when invasive recordings were performed 6-50 years (mean 28.2 years)]. Of the seizures 41.3% arose from the amygdala/hippocampus complex (AHC), 34.7% from the TN, 22% were simultaneously recorded from AHC and TN (indeterminate seizure onset), and 2% from other regions. In three patients, seizure onset was recorded only from the AHC. In patients with severe hippocampal sclerosis only 12% of the seizures arose from the TN, whereas in patients with mild hippocampal sclerosis 58% arose from the TN. The type of cortical dysplasia, however, did not predict seizure onset in the AHC or TN. Propagation time from the TN to the AHC tended to be shorter (mean 7.4 s) than vice versa (mean 13.7 s). The most common initial ictal patterns in the AHC were rhythmic beta activity (<25 Hz) and repetitive sharp waves, and in the TN were fast activity (>25 Hz) and repetitive sharp waves. The interictal patterns over the TN were similar to those seen over extratemporal focal cortical dysplasias. Simultaneous recordings from the hippocampus and the TN strongly suggest that dysplastic tissue in the TN is often epileptogenic. The quantitative contribution of the hippocampus to seizure generation corresponded with the degree of hippocampal pathology, whereas different subtypes of cortical dysplasia did not affect its relative contribution to seizure generation and even mild forms of dysplasia were epileptogenic.
Brain 01/2006; 129(Pt 1):82-95. · 9.46 Impact Factor
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Susanne Fauser,
Andreas Schulze-Bonhage,
Juergen Honegger,
Hans Carmona,
Hans-Juergen Huppertz,
Georgios Pantazis,
Sabine Rona,
Thomas Bast,
Karl Strobl,
Bernhard J Steinhoff,
Rudolf Korinthenberg,
Dietz Rating,
Benedikt Volk,
Josef Zentner
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ABSTRACT: The purpose of this study was to assess whether the histological subtype of focal cortical dysplasia and dual pathology affect surgical outcome in patients with medically intractable epilepsy due to focal cortical dysplasia (FCD). We retrospectively analysed the outcome of 67 patients from 2 to 66 years of age at follow-up periods of 6 to 48 months after epilepsy surgery. Histological subtypes were classified according to Palmini and included a few cases with mild histological abnormalities corresponding to the definition of mild malformations of cortical development. The seizure outcome was classified according to Engel and evaluated at the last follow-up visit as well as at follow-up periods of 12 and 24 months after surgery. The outcome in patients with FCD and additional hippocampal pathology (dual pathology) was analysed separately. Distribution of histological subtypes differed in temporal and extratemporal localization, with a significantly higher extratemporal prevalence of FCD type 2. There was a tendency towards better postsurgical outcome related to the last follow-up visit in patients with more subtle abnormalities classified as mild malformations of cortical development (mMCD) (63% Engel Ia), FCD type 1a (67% Engel Ia) and FCD type 1b (55% Engel Ia) compared with patients with FCD type 2a (43% Engel Ia) and FCD type 2b (Taylor type) (50% Engel Ia). Considering the outcome at follow-up periods over 12 and 24 months, complete seizure-freedom was achieved significantly more often in patients with FCD type 1 and mMCD than with FCD type 2, and seizure reduction by less than 75% (Engel IV) occurred in more patients with FCD type 2a compared with the other subgroups. This tendency was seen in the whole patient group and in the extratemporal subgroup. Patients with dual pathology almost always had temporal lobe epilepsy; the outcome in this patient group was generally favourable (66% complete seizure-freedom at the last follow-up visit). The outcome remained almost constant with longer periods of follow-up. We conclude that patients with FCD type 1 and mMCD had a better outcome compared with those with more severe forms of cortical dysplasia. A higher incidence of FCD type 1 in temporal localization did not allow the effects of histological subtype and localization to be separated. A subanalysis of extratemporal FCDs, however, revealed a similar tendency for a better outcome with FCD type 1, suggesting that the histological subtype itself seems to be at least a relevant cofactor influencing postsurgical outcome.
Brain 12/2004; 127(Pt 11):2406-18. · 9.46 Impact Factor
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ABSTRACT: Balloon cells are histopathological hallmarks of various cortical malformations, i.e., focal cortical dysplasia (Taylor's type, FCD IIb), hemimegalencephaly (HME) or cortical tubers (tuberous sclerosis, TSC). Whether this intriguing cell type results from similar pathogenetic pathways remains to be shown. Here, we analyzed the immunohistochemical distribution pattern of the CD34 epitope in surgical specimens from 34 patients with FCD IIb, compared to that of 6 patients with TSC and 3 patients with HME. In normal brain, CD34 occurs only transiently during neurulation, but cannot be detected in mature neuroectodermal cell progenies. In contrast, 58% of our patients showed CD34 immunoreactivity within a subpopulation of balloon cells. Interestingly, CD34-positive balloon cells were confined to the white matter, but never observed in neocortical layers. Furthermore, balloon cells expressing neurofilament protein were also restricted to white matter, whereas GFAP-positive balloon cells were observed either in white or gray matter location. Clinical characteristics did not significantly differ between patients with CD34-positive versus CD34-negative lesions. No significant correlation was found between CD34 expression and genetic alterations of the TSC1 gene, which is affected in many FCD and TSC patients and which plays a role in the regulation of cell size. Further studies are warranted to clarify the restricted expression of CD34 in balloon cells of the white matter.
Acta Neuropathologica 11/2004; 108(4):272-8. · 9.32 Impact Factor
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ABSTRACT: Based on experimental data from animal studies different theories regarding the size of an epileptic focus have been postulated which range from single pacemaker cells to extended neuronal networks. We report a case which gives further information about the size of a human epileptic focus which can trigger manifest epileptic seizures. We report a 22-year-old man with medically refractory temporal lobe epilepsy. This patient suffered from brief complex partial seizures and frequent epigastric auras. To differentiate a mesiotemporal from a temporolateral seizure origin the patient was implanted with a 10 contact depth electrode from a posterior approach into the right hippocampus, and additional temporobasal/temporolateral subdural strip electrodes. Depth recordings revealed an electrographic status with continuous rhythmic sharp wave activity (1 Hz), the field of which was confined to a diameter of less than 1 cm in the anterior hippocampus, whereas temporobasal subdural strip electrodes did not display this activity. Periodically, spread of this activity occurred to the amygdala, to the posterior part of the hippocampus, and less often to the temporobasal cortex. Most seizure patterns remained subclinical, few of them became symptomatic as partial seizures. This case demonstrates that a hippocampal epileptic focus causing electrographic focal status epilepticus may be limited to a volume of less than 1 cm in diameter. This observation is discussed with regard to implantation strategies and to possible superselective resective or modulatory approaches in the treatment of such limited epileptogenic areas.
Clinical Neurophysiology 11/2004; 115(10):2274-9. · 3.41 Impact Factor
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ABSTRACT: Postictal coughing has so far been reported to indicate a temporal origin of focal epilepsy. A trend towards non-dominant hemisphere lateralization and mesial temporal localization has been suggested. However, postictal coughing has also been reported in a few patients with extratemporal epilepsies. We have retrospectively evaluated the localizing and lateralizing value of ictal/postictal coughing in 197 patients with temporal and extratemporal epilepsy who received presurgical video-EEG long-term recordings from 1999 to 2001. There was no statistical significant difference in percentage of coughing patients in both groups. However, only patients belonging to the temporal group presented with coughing as a regular element of seizure semiology (simple partial and complex partial seizures) whereas in the extratemporal group coughing occurred more sporadically. Within the temporal group a statistically significant tendency to left-sided seizure onset and a statistically not significant preponderance of mesial seizure onset was observed. Additional vegetative signs were observed only in about half of the patients. These results suggest that coughing occurs in both temporal and extratemporal lobe epilepsy and may only be indicative of temporal lobe seizure onset if representing a regular semiologic element. Coughing may be due to two different mechanisms, one dependent and the other independent from additional vegetative symptoms.
Seizure 10/2004; 13(6):403-10. · 1.80 Impact Factor
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ABSTRACT: Simultaneous interictal EEG and magnetoencephalography (MEG) recordings were used for noninvasive analysis of epileptogenicity in focal cortical dysplasia (FCD). The results of two different approach methods (multiple source analysis of averaged spikes and single dipole peak localization of single spikes) were compared with pre- and postoperative anatomic magnetic resonance imaging (MRI).
We studied nine children and adolescents (age, 3.5-15.9 years) with localization-related epilepsy and FCD diagnosis based on MRI. Five patients underwent epilepsy surgery, two of them after long-term recording with subdural grid electrodes, and one after intraoperative electrocorticography.
The 122-channel whole-head MEGs and 33-channel EEGs were recorded simultaneously for 25 to 40 min. Interictal spikes were identified visually and used as templates to search for similar spatiotemporal spike patterns throughout the recording. With the BESA program, similar spikes (r > 0.85) were detected, averaged, high-pass filtered (5 Hz) to enhance spike onset, and subjected to multiple spatiotemporal source analysis with a multishell spherical head model. Peak activity from single spikes was modeled by single dipoles for the same subset of spikes. Source localization was visualized by superposition on T1-weighted MRI and compared with the lesion identified in T1- and T2-weighted MRI. In the five cases undergoing epilepsy surgery, the results were correlated with invasive recordings, postoperative MRI, and outcome.
In all cases, the analysis of averaged spikes showed a localization of onset- and peak-related sources within the visible lesion for both EEG and MEG. Of the single spikes, 128 (45%; total 284) were localizable at the peak in MEG, and 170 (60%) in EEG. Of these, 91% localized within the lesion with MEG, and 93.5% with EEG. In three of five patients operated on, the resected area included the onset zones of averaged EEG and MEG spike activity. These patients had excellent postoperative outcome, whereas the others did not become seizure free.
Consistent MEG and EEG spike localization in the lesional zone confirmed the hypothesis of intrinsic epileptogenicity in FCD.
Epilepsia 07/2004; 45(6):621-31. · 3.96 Impact Factor
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ABSTRACT: Focal cortical dysplasia (FCD), a frequent cause of partial epilepsy, is often associated with blurring of the gray-white matter junction in magnetic resonance images (MRI). To improve the recognition and delineation of FCD we developed a novel voxel-based image post-processing method for enhanced visualization of blurred gray-white matter junctions.
Using standard algorithms of statistical parametric mapping software (SPM99) a T1-weighted MRI volume data set is normalized and segmented. The distribution of gray and white matter is analyzed on a voxelwise basis and compared with a normal database. Based on this analysis, a three-dimensional feature map is created which highlights brain areas with blurred gray-white matter transition. This method was applied to the MRI data of 25 epilepsy patients with histologically proven FCD.
In 18/25 patients the new feature maps clearly showed that the dysplastic lesions were accompanied by blurring of the gray-white matter junction. Combined with a formerly published method of voxel-based 3D MRI analysis, 21/25 FCD lesions were shown to be associated with either blurring or abnormal extension of gray matter beyond the normal cortical ribbon, including four cases with lesions not or incompletely recognized on conventional MRI.
The MRI post-processing presented here improves the visualization of FCD and may increase the diagnostic yield of MRI. Thereby, it provides a valuable additional diagnostic tool in the presurgical evaluation of epilepsy patients.
Epilepsy Research 67(1-2):35-50. · 2.29 Impact Factor
