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Hippocampal Sclerosis (hippocampal + sclerosis)

Distribution by Scientific Domains

Medical Sciences	98%

Distribution within Medical Sciences

Neurology	88%
Pathology	10%

Selected Abstracts

Hippocampal Malformations Do Not Necessarily Evolve into Hippocampal Sclerosis

EPILEPSIA, Issue 6 2005
Arjune Sen
Summary:,Purpose: Hippocampal malformations have been proposed to underlie or evolve into hippocampal sclerosis, a common cause of refractory partial epilepsy. We report two patients with chronic epilepsy and developmental abnormalities of the hippocampus and cortex. We seek to address, in patients with recurrent convulsive seizures over many decades, whether hippocampal malformations necessarily progress to hippocampal sclerosis. Methods: The first patient died at age 76 years and had experienced convulsive seizures for 43 years. The second patient, aged 64 years at death, had experienced convulsive seizures for 49 years. The brains were processed routinely. Immunohistochemistry for dynorphin and neuropeptide Y was performed. Results: The first case exhibited bilateral perisylvian polymicrogyria. Both hippocampi demonstrated abnormal convolution in the CA1 subfield and subiculum. In the second case, periventricular heterotopia was found in the wall of the right lateral ventricle. The right hippocampus was abnormally oriented with excessive convolutions of the pyramidal cell layer between CA1 and the subiculum. In neither patient did the hippocampi exhibit neuronal loss. Furthermore, dynorphin immunohistochemistry revealed no reactivity in the molecular layers, and staining with neuropeptide Y confirmed normal numbers of hilar interneurons. Conclusions: These two cases demonstrate histologically that, even in long-standing epilepsy, malformations of the hippocampus do not necessarily develop into hippocampal sclerosis. [source]

Correlation between 1H MRS and Memory before and after Surgery in Mesial Temporal Lobe Epilepsy with Hippocampal Sclerosis

EPILEPSIA, Issue 6 2004
Lütfü Hano
Summary: Purpose: Proton magnetic resonance spectroscopy (1H MRS), which can demonstrate neuronal loss and gliosis, may be used as a sensitive tool for lateralization of temporal lobe epilepsy (TLE). Although the correlation between the memory functions and 1H MRS has been investigated, its predictive value after surgery has not been studied previously. This study evaluated memory and 1H MRS values of medically intractable patients with mesial TLE and hippocampal sclerosis (MTLE-HS) before and after selective amygdalohippocampectomy (SAH). Methods: Twenty-two patients underwent memory tests and 1H MRS investigation before and 6 months after SAH and were compared with nine control subjects. Results: The 1H MRS scores were found to be significantly low on the pathological side of the patients. Both right-sided 1H MRS of right TLE and left-sided 1H MRS values of left TLE patients were correlated only with verbal memory scores. Statistical analysis did not reveal any significance for nonverbal memory scores for both TLE groups on either side, which showed no significant correlation between material specificity and 1H MRS findings. Conversely, regression analyses demonstrated that high right- and low left-sided 1H MRS values obtained before surgery may predict a decline in verbal learning scores after surgery. Conclusions:1H MRS can be considered as a useful tool to determine the lateralization in patients with MTLE-HS before the surgery. Although only a weak relation exists between the MRS values and memory scores, presurgical MRS scores may be predictive for a possible deterioration in verbal memory after surgery. However, further studies with higher numbers of cases are needed for confirmation of the results. [source]

Neocortical Temporal FDG-PET Hypometabolism Correlates with Temporal Lobe Atrophy in Hippocampal Sclerosis Associated with Microscopic Cortical Dysplasia

EPILEPSIA, Issue 4 2003
Beate Diehl
Summary: ,Purpose: Medically intractable temporal lobe epilepsy (TLE) due to hippocampal sclerosis (HS), with or without cortical dysplasia (CD), is associated with atrophy of the hippocampal formation and regional fluorodeoxyglucose positron-emission tomography (FDG-PET) hypometabolism. The relation between areas of functional and structural abnormalities is not well understood. We investigate the relation between FDG-PET metabolism and temporal lobe (TL) and hippocampal atrophy in patients with histologically proven isolated HS and HS associated with CD. Methods: Twenty-three patients underwent en bloc resection of the mesial and anterolateral neocortical structures. Ten patients were diagnosed with isolated HS; 13 patients had associated microscopic CD. Temporal lobe volumes (TLVs) and hippocampal volumes were measured. Magnetic resonance imaging (MRI) and PET were co-registered, and regions of interest (ROIs) determined as gray matter of the mesial, lateral, and anterior temporal lobe. Results: All patients (HS with or without CD) had significant ipsilateral PET hypometabolism in all three regions studied (p < 0.0001). In patients with isolated HS, the most prominent hypometabolism was in the anterior and mesial temporal lobe, whereas in dual pathology, it was in the lateral temporal lobe. TLVs and hippocampal volumes were significantly smaller on the epileptogenic side (p < 0.05). The PET asymmetries ipsilateral/contralateral to the epileptogenic zone and TLV asymmetries correlated significantly for the anterior and lateral temporal lobes (p < 0.05) in the HS+CD group, but not in the isolated HS group. Mesial temporal hypometabolism was not significantly different between the two groups. Conclusions: Temporal neocortical microscopic CD with concurrent HS is associated with more prominent lateral temporal metabolic dysfunction compared with isolated HS in TL atrophy. Further studies are needed to confirm these findings and correlate the PET hypometabolic patterns with outcome data in patients operated on for HS with or without CD. [source]

Stroke in the developing brain and intractable epilepsy: effect of timing on hippocampal sclerosis

DEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 9 2003
Waney Squier FRCP FRC Path
A detailed study was made of the pathology of specimens removed by hemispherectomy for the treatment of intractable epilepsy in children with unilateral middle cerebral artery stroke. Neuropathological criteria were used to differentiate strokes that occurred in early intrauterine development (before 28 weeks gestational age) from those occurring in the last trimester, at birth, or after birth: 19 children had early strokes and 21 late. There was no difference in seizure history or occurrence of febrile convulsions in these two groups. Hippocampal tissue was available in 20 patients; pathology in the hippocampus, remote from the infarcted area, showed a marked difference between early-onset and late-onset groups. Hippocampal sclerosis was uncommon in children with early-onset strokes but developed in most of the children whose strokes were of later origin. However, hippocampal sclerosis was more closely related to a clinical history of a late initial precipitating insult irrespective of infarct timing. These findings demonstrate the changing vulnerability of the developing brain and show that hippocampal pathology is more closely related to the timing of an insult than seizure history or the occurrence of febrile convulsions. [source]

Role of cortical dysplasia in epileptogenesis following prolonged febrile seizure

EPILEPSIA, Issue 9 2010
Kyung-Il Park
Summary Purpose:, Hippocampal sclerosis, characterized by prominent neuronal loss and reactive gliosis, is the most common pathology in human temporal lobe epilepsy (TLE). Although prolonged febrile convulsion (FC) is a risk factor of TLE, it is not clear whether FC provokes hippocampal sclerosis and subsequent TLE. Given that underlying brain lesions, such as cortical dysplasia (CD), in the immature brain predispose patients to FC, CD may link FC and TLE. However, the role of CD in epileptogenesis after FC is also unclear. Here, we investigated whether inborn CD increases the risk of later epilepsy induced by prolonged FC using a rat model. Methods:, Experimental CD was induced by in utero exposure of methylazoxymethanol (MAM). Rat pups from MAM-treated or control rats were then subjected to prolonged FC. We examined morphologic changes in the hippocampi with respect to neuronal loss, reactive gliosis, and synaptogenesis, and evaluated spontaneous recurrent seizures (SRS) by long-term video-EEG (electroencephalography). Results:, The MAM+FC group had a significantly lower hippocampal neuronal density in the CA1 and dentate hilus than other control groups. A robust increase in glial cells and synaptic reorganization was also detected in the MAM+FC groups. Furthermore, later SRS occurred in all rats in the MAM+FC group and in 50% and 25% of the rats in the FC-only and MAM-only group, respectively. The frequency and total duration of SRS was highest in the MAM+FC group. Discussion:, Our results suggest that preexisting CD in the immature brain augments the proepileptogenic effects of prolonged FC, leading to TLE. [source]

Specific Epileptic Syndromes Are Rare Even in Tertiary Epilepsy Centers: A Patient-oriented Approach to Epilepsy Classification

EPILEPSIA, Issue 3 2004
Christoph Kellinghaus
Summary: Purpose: To assess the practicability and reliability of a five-dimensional patient-oriented epilepsy classification and to compare it with the International League Against Epilepsy (ILAE) classification of epilepsy and epileptic syndromes. The dimensions consist of the epileptogenic zone, semiologic seizure type(s), etiology, related medical conditions, and seizure frequency. Methods: The 185 epilepsy patients (94 adults, 91 children, aged 18 years or younger) were randomly selected from the database of a tertiary epilepsy center and the general neurological department of a metropolitan hospital (28 adults). The charts were reviewed independently by two investigators and classified according to both the ILAE and the patient-oriented classification. Interrater reliability was assessed, and a final consensus among all investigators was established. Results: Only four (4%) adults and 19 (21%) children were diagnosed with a specific epilepsy syndrome of the ILAE classification. All other patients were in unspecific categories. The patient-oriented classification revealed that 64 adults and 56 children had focal epilepsy. In an additional 34 adults and 45 children, the epileptogenic zone could be localized to a certain brain region, and in 14 adults and five children, the epileptogenic zone could be lateralized. Fourteen adults and 21 children had generalized epilepsy. In 16 adults and 14 children, it remained unclear whether the epilepsy was focal or generalized. Generalized simple motor seizures were found in 66 adults and 52 children, representing the most frequent seizure type. Etiology could be determined in 40 adults and 45 children. Hippocampal sclerosis was the most frequent etiology in adults (10%), and cortical dysplasia (9%), in children. Seven adults and 31 children had at least daily seizures. Seventeen adults and 26 children had rare or no seizures at their last documented contact. The most frequent related medical conditions were psychiatric disorders and mental retardation. Interrater agreement was high (kappa values of 0.8 to 0.9) for both the patient-oriented and the ILAE classification. Conclusions: Specific epilepsy syndromes included in the current ILAE classification are rare even in a tertiary epilepsy center. Most patients are included in unspecific categories that provide only incomplete information. In contrast, all of the patients could be classified by the five-dimensional patient-oriented classification, providing all essential information for the management of the patients with a high degree of interrater reliability. [source]

Magnetic Resonance Imaging Follow-up of Progressive Hippocampal Changes in a Mouse Model of Mesial Temporal Lobe Epilepsy

EPILEPSIA, Issue 6 2000
Viviane Bouilleret
Summary: Purpose: Hippocampal sclerosis (HS) is the most frequent lesion found in mesial temporal lobe epilepsy (mTLE). MR imaging is considered to be the most sensitive and specific method to detect HS. Despite extensive studies performed on humans and except in a recent study, the morphologic pattern of HS is usually analyzed when the disease has already fully developed, thus not allowing any insight into the mapping of the progressive morphologic changes inducing the development of mTLE. We have recently characterized a model of mTLE that reproduces the unilateral pattern of HS, induced by intrahippocampal injection of low doses of kainate (KA) in mice. Methods: In this study, we monitored the temporal evolution of the development of HS in this model of mTLE by using T2 -weighted sequence, T2 -relaxation time measurements, and T1 -weighted spin-echo technique after injection of gadolinium, from 1 h to 120 days after KA injection. Results: HS induced by intrahippocampal KA injection occurred in two phases. First, we observed a transient hyperintense T2 -weighted signal in the cortex above the injected hippocampus, most likely indicative of vasogenic edema partly due to the neurotoxic effect of KA. The concomitant increase in the T2 signal in the injected hippocampus and ipsilateral amygdala likely reflects the phase of cytotoxic edema occurring probably in relation to the excitotoxic consequences of both KA and seizure activity. Second, from 15 days on, a persistent unilateral increased T2 signal was detected in the hippocampus, which most probably reflects gliosis. Conclusions: Our findings indicate that longitudinal follow-up would permit a better understanding of the mechanisms underlying the constitution of HS in humans and eventually development of prevention strategies. [source]

Hippocampal sclerosis is a progressive disorder: A longitudinal volumetric MRI study

ANNALS OF NEUROLOGY, Issue 3 2003
Darren Fuerst PhD
Twelve patients with refractory temporal lobe epilepsy and unilateral hippocampal sclerosis had repeat volumetric magnetic resonance imaging scans after a mean of 3.4 years to determine whether progressive hippocampal volume loss occurred. Seizure-free patients showed no change in hippocampal volume. Patients with continuing seizures had a decline in ipsilateral hippocampal volume that correlated with seizure frequency. Patients with medically refractory temporal lobe epilepsy and unilateral hippocampal sclerosis have progressive hippocampal atrophy. Ann Neurol 2003;53:413,416 [source]

Parenchymal lesions in pharmacoresistant temporal lobe epilepsy: dual and multiple pathology

ACTA NEUROLOGICA SCANDINAVICA, Issue 3 2005
S. H. Eriksson
Objectives,,, Dual pathology is reported in 5,30% of temporal lobe resections performed in pharmacoresistant epilepsy. Dual pathology may be of importance for surgical planning and also for the understanding of the pathogenesis of epilepsy. We describe the frequency of dual or multiple pathology, i.e. more than one histopathological diagnosis, in adults with temporal lobe resections. Material and Methods,,, Surgical specimens from 33 consecutive patients with resections including mesial as well as neocortical temporal structures were reviewed. All histopathological findings were recorded. Post-mortem specimens from 11 control subjects were also reviewed. Results,,, Dual or multiple pathology was found in almost half of the epilepsy patients (48%). Hippocampal sclerosis was found in 25 patients (76%), malformations of cortical development in 15 (46%), of which 12 (36%) were microdysgenesis, and low-grade tumours in seven (21%). Apart from mild gliosis, there were no histopathological changes in the control specimens. Conclusion,,, Dual or multiple pathology was a common finding in this group of adults with temporal lobe resections. In order to increase our understanding of how aetiological factors may combine in the development of seizures, we consider it relevant and important to report all histopathological findings in epilepsy surgery series. [source]

Stroke in the developing brain and intractable epilepsy: effect of timing on hippocampal sclerosis

Reliability of patterns of hippocampal sclerosis as predictors of postsurgical outcome

EPILEPSIA, Issue 9 2010
Maria Thom
Summary Purpose:, Around one-third of patients undergoing temporal lobe surgery for the treatment of intractable temporal lobe epilepsy with hippocampal sclerosis (HS) fail to become seizure-free. Identifying reliable predictors of poor surgical outcome would be helpful in management. Atypical patterns of HS may be associated with poorer outcomes. Our aim was to identify atypical HS cases from a large surgical series and to correlate pathology with clinical and outcome data. Methods:, Quantitative neuropathologic evaluation on 165 hippocampal surgical specimens and 21 control hippocampi was carried out on NeuN-stained sections. Neuronal densities (NDs) were measured in CA4, CA3, CA2, and CA1 subfields. The severity of granule cell dispersion (GCD) was assessed. Results:, Comparison with control ND values identified the following patterns based on the severity and distribution of neuronal loss: classical HS (CHS; n = 60) and total HS (THS; n = 39). Atypical patterns were present in 30% of cases, including end-folium sclerosis (EFS; n = 5), CA1 predominant pattern (CA1p; n = 9), and indeterminate HS (IHS, n = 35). No HS was noted in 17 cases. Poorest outcomes were noted for no-HS, and CA1p groups with 33,44% International League Against Epilepsy (ILAE) class I at up to 2 years follow-up compared to 69% for CHS (p < 0.05). GCD associated with HS type (p < 0.01), but not with outcome. Conclusions:, These findings support the identification and delineation of atypical patterns of HS using quantitative methods. Atypical patterns may represent distinct clinicopathologic subtypes and may have predictive value following epilepsy surgery. [source]

Role of cortical dysplasia in epileptogenesis following prolonged febrile seizure

Clinical features of seizures associated with parahippocampal/inferior temporal lesions compared to those with hippocampal sclerosis

EPILEPSIA, Issue 9 2010
Laura Mirandola
Summary Temporal lobe epilepsy (TLE) is not a unitary electroclinical imaging syndrome. We asked if seizures arising from the parahippocampal-inferior temporal (PIT) region differ from those associated with hippocampal sclerosis (HS). The electroclinical features of 22 patients with HS and 14 patients with lesions in the PIT region who underwent epilepsy surgery and were seizure free for at least 2 years postoperatively were analyzed retrospectively. Patients with PIT lesions had a higher frequency of hypermotor and bilateral features and a lower frequency of behavioral arrest at the onset of seizure compared to cases with HS, suggesting that TLE originating in the PIT area can mimic frontal lobe epilepsy or contralateral mesial TLE. [source]

Epilepsy with dual pathology: Surgical treatment of cortical dysplasia accompanied by hippocampal sclerosis

EPILEPSIA, Issue 8 2010
Dong W. Kim
Summary Purpose:, The presence of two or more epileptogenic pathologies in patients with epilepsy is often observed, and the coexistence of focal cortical dysplasia (FCD) with hippocampal sclerosis (HS) is one of the most frequent clinical presentations. Although surgical resection has been an important treatment for patients with refractory epilepsy associated with FCD, there are few studies on the surgical treatment of FCD accompanied by HS, and treatment by resection of both neocortical dysplastic tissue and hippocampus is still controversial. Methods:, We retrospectively recruited epilepsy patients who had undergone surgical treatment for refractory epilepsy with the pathologic diagnosis of FCD and the radiologic evidence of HS. We evaluated the prognostic roles of clinical factors, various diagnostic modalities, surgical procedures, and the severity of pathology. Results:, A total of 40 patients were included, and only 35.0% of patients became seizure free. Complete resection of the epileptogenic area (p = 0.02), and the presence of dysmorphic neurons or balloon cells on histopathology (p = 0.01) were associated with favorable surgical outcomes. Patients who underwent hippocampal resection were more likely to have a favorable surgical outcome (p = 0.02). Conclusions:, We show that patients with complete resection of epileptogenic area, the presence of dysmorphic neurons or balloon cells on histopathology, or resection of hippocampus have a higher chance of a favorable surgical outcome. We believe that this observation is useful in planning of surgical procedures and predicting the prognoses of individual patients with FCD patients accompanied by HS. [source]

Involvement of the thalamocortical network in TLE with and without mesiotemporal sclerosis

EPILEPSIA, Issue 8 2010
Susanne G. Mueller
Summary Purpose:, The thalamus plays an important role in seizure propagation in temporal lobe epilepsy (TLE). This study investigated how structural abnormalities in the focus, ipsilateral thalamus and extrafocal cortical structures relate to each other in TLE with mesiotemporal sclerosis (TLE-MTS) and without hippocampal sclerosis (TLE-no). Methods:, T1 and high-resolution T2 images were acquired on a 4T magnet in 29 controls, 15 TLE-MTS cases, and 14 TLE-no. Thalamus volumes were obtained by warping a labeled atlas onto each subject's brain. Deformation-based morphometry was used to identify regions of thalamic volume loss and FreeSurfer for cortical thickness measurements. CA1 volumes were obtained from high-resolution T2 images. Multiple regression analysis and correlation analyses for voxel- and vertex-based analyses were performed in SPM2 and FreeSurfer. Results:, TLE-MTS had bilateral volume loss in the anterior thalamus, which was correlated with CA1 volume and cortical thinning in the mesiotemporal lobe. TLE-no had less severe volume loss in the dorsal lateral nucleus, which was correlated with thinning in the mesiotemporal region but not with extratemporal thinning. Discussion:, The findings suggest that seizure propagation from the presumed epileptogenic focus or regions close to it into the thalamus occurs in TLE-MTS and TLE-no and results in circumscribed neuronal loss in the thalamus. However, seizure spread beyond the thalamus seems not to be responsible for the extensive extratemporal cortical abnormalities in TLE. [source]

Surgery for temporal lobe epilepsy associated with mesial temporal sclerosis in the older patient: A long-term follow-up

EPILEPSIA, Issue 6 2010
Michael Murphy
Summary Purpose:, To assess the outcomes from temporal lobectomy for hippocampal sclerosis in patients 50 years or older. Controversy exists as to the suitability of older patients for epilepsy surgery, with most of the previous studies demonstrating a correlation between increasing age and poor outcome. However, the inclusion of temporal lobe epilepsy of multiple etiologies has confounded many previous studies of this age group. Methods:, Twenty-one patients aged 50 years or older (mean 54.9 years) at the time of surgery were included in the study group. All patients had a pathologic diagnosis of hippocampal sclerosis. A retrospective analysis was performed comparing seizure outcomes following a standardized anterior temporal lobectomy with those from 103 patients younger than 50 (mean age 34.7 years) operated upon over the same time period. The mean follow-up period for the study was 9.57 years. Results:, Twenty of the 21 patients in the older group (95.2%) had a satisfactory seizure outcome (Engel classes I and II) compared with 90.3% of the younger patients. There was no statistically significant difference in the outcomes between the two groups (p = 0.719). Across both groups of patients combined, there was no significant difference between the mean age in the patients with a satisfactory seizure outcome compared to those with an unsatisfactory outcome (38.3 vs. 34.7 years, p = 0.213). Discussion:, Patients 50 years or older with intractable seizures from hippocampal sclerosis have seizure outcomes following temporal lobectomy that are comparable to young patients over the long term. Older patients should not be denied treatment on the basis of age. [source]

Hippocampal volume assessment in temporal lobe epilepsy: How good is automated segmentation?

EPILEPSIA, Issue 12 2009
Heath R. Pardoe
Summary Purpose:, Quantitative measurement of hippocampal volume using structural magnetic resonance imaging (MRI) is a valuable tool for detection and lateralization of mesial temporal lobe epilepsy with hippocampal sclerosis (mTLE). We compare two automated hippocampal volume methodologies and manual hippocampal volumetry to determine which technique is most sensitive for the detection of hippocampal atrophy in mTLE. Methods:, We acquired a three-dimensional (3D) volumetric sequence in 10 patients with left-lateralized mTLE and 10 age-matched controls. Hippocampal volumes were measured manually, and using the software packages Freesurfer and FSL-FIRST. The sensitivities of the techniques were compared by determining the effect size for average volume reduction in patients with mTLE compared to controls. The volumes and spatial overlap of the automated and manual segmentations were also compared. Results:, Significant volume reduction in affected hippocampi in mTLE compared to controls was detected by manual hippocampal volume measurement (p < 0.01, effect size 33.2%), Freesurfer (p < 0.01, effect size 20.8%), and FSL-FIRST (p < 0.01, effect size 13.6%) after correction for brain volume. Freesurfer correlated reasonably (r = 0.74, p << 0.01) with this manual segmentation and FSL-FIRST relatively poorly (r = 0.47, p << 0.01). The spatial overlap between manual and automated segmentation was reduced in affected hippocampi, suggesting the accuracy of automated segmentation is reduced in pathologic brains. Discussion:, Expert manual hippocampal volumetry is more sensitive than both automated methods for the detection of hippocampal atrophy associated with mTLE. In our study Freesurfer was the most sensitive to hippocampal atrophy in mTLE and could be used if expert manual segmentation is not available. [source]

Extent of initial injury determines language lateralization in mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS)

EPILEPSIA, Issue 10 2009
Chaturbhuj Rathore
Summary Purpose:, To assess the prevalence and attributes of atypical language lateralization (ALL) in patients with left mesial temporal lobe epilepsy associated with hippocampal sclerosis (MTLE-HS). Methods:, We recruited consecutive patients with left MTLE-HS, who had undergone resective surgery and had pathologically proven HS. Based on the Wada test, language lateralization was classified into typical (left hemispheric) or atypical (right hemispheric or codominant). We assessed the attributes of patients with ALL using univariate and multivariate analyses. Results:, Of 124 patients with left MTLE-HS, 23 (18.5%) had ALL. ALL occurred more frequently in patients with severe initial precipitating injury (IPI), early onset of epilepsy, and a short latent period between IPI and onset of habitual seizures. ALL was more common in patients with bitemporal and extratemporal interictal epileptiform discharges (IEDs) on electroencephalogram (EEG) and extratemporal changes on magnetic resonance imaging (MRI). On multivariate analyses, the age at onset of habitual seizures <6 years, atypical IPI, nonunilateral temporal IEDs, and extratemporal MRI abnormalities independently predicted ALL. The likelihood of ALL was very low (,1%) when all of these four risk factors were absent, whereas it was very high (>95%), if any three or all four of them were present. Conclusions:, ALL occurs in one-fifth of patients with left MTLE-HS. ALL is more frequent in those with structural or functional extrahippocampal involvement and early onset of epilepsy interrupting the development of normal language networks. Because ALL is uncommon in those with damage/dysfunction restricted to the hippocampus, the hippocampus itself may have only a limited role in determining language lateralization. [source]

Subfield atrophy pattern in temporal lobe epilepsy with and without mesial sclerosis detected by high-resolution MRI at 4 Tesla: Preliminary results

EPILEPSIA, Issue 6 2009
Susanne G. Mueller
Summary Purpose:, High-resolution magnetic resonance imaging (MRI) at 4 Tesla depicts details of the internal structure of the hippocampus not visible at 1.5 Tesla, and so allows for in vivo parcellation of different hippocampal subfields. The aim of this study was to test if distinct subfield atrophy patterns can be detected in temporal lobe epilepsy (TLE) with mesial temporal sclerosis (TLE-MTS) and without (TLE-no) hippocampal sclerosis. Methods:, High-resolution T2 -weighted hippocampal images were acquired in 34 controls: 15 TLE-MTS and 18 TLE-no. Entorhinal cortex (ERC), subiculum (SUB), CA1, CA2, and CA3, and dentate (CA3&DG) volumes were determined using a manual parcellation scheme. Results:, TLE-MTS had significantly smaller ipsilateral CA1, CA2, CA3&DG, and total hippocampal volume than controls or TLE-no. Mean ipsilateral CA1 and CA3&DG z-scores were significantly lower than ipsilateral CA2, ERC, and SUB z-scores. There were no significant differences between the various subfield or hippocampal z-scores on either the ipsi- or the contralateral side in TLE-no. Using a z-score ,,2.0 to identify severe volume loss, the following atrophy patterns were found in TLE-MTS: CA1 atrophy, CA3&DG atrophy, CA1 and CA3&DG atrophy, and global hippocampal atrophy. Significant subfield atrophy was found in three TLE-no: contralateral SUB atrophy, bilateral CA3&DG atrophy, and ipsilateral ERC and SUB atrophy. Discussion:, Using a manual parcellation scheme on 4 Tesla high-resolution MRI, we found the characteristic ipsilateral CA1 and CA3&DG atrophy described in TLE-MTS. Seventeen percent of the TLE-no had subfield atrophy despite normal total hippocampal volume. These findings indicate that high-resolution MRI and subfield volumetry provide superior information compared to standard hippocampal volumetry. [source]

Spontaneous periictal leaving behavior: A potential lateralizing sign in mesial temporal lobe epilepsy

EPILEPSIA, Issue 6 2009
Liri Jin
Summary Purpose:, Seizure-related spontaneous leaving behavior (LB) is an uncommonly reported phenomenon. The aim of this study was to determine its frequency, clinical significance, and especially its lateralizing value. Methods:, We analyzed retrospectively the spontaneous periictal LB occurring in complex partial seizures (CPS) of 138 patients with medically refractory mesial temporal lobe epilepsy (MTLE) with excellent postoperative seizure outcome and pathologic finding of hippocampal sclerosis. The relation of LB occurring in different phases of CPS to the side of resection was investigated. Results:, The overall frequency of periictal LB was 8.3% of 517 CPS and 25.2% of 123 patients. Among the 12 patients with ictal LB, 9 patients had epileptogenic focus ipsilateral to language dominant side, whereas the remaining 3 had seizure onset in the nondominant side. Conversely, 8 of 11 patients with postictal LB had foci in the nondominant side, and only three patients' seizures originated in the dominant side. Therefore, it was more likely for patients with left MTLE to show ictal LB and for those with right foci to display postictal LB (p = 0.03). Conclusions:, LB may represent a potential lateralizing sign. When LB occurs ictally, it may indicate seizure onset in the dominant temporal lobe, and LB occurring postictally indicates nondominant side seizure onset in patients with MTLE. [source]

Differential effects of temporal pole resection with amygdalohippocampectomy versus selective amygdalohippocampectomy on material-specific memory in patients with mesial temporal lobe epilepsy

EPILEPSIA, Issue 1 2008
Christoph Helmstaedter
Summary Purpose: In the surgical treatment of mesial temporal lobe epilepsy, there is converging evidence that individually tailored or selective approaches have a favorable cognitive outcome compared to standard resections. There is, however, also evidence that due to collateral damage, selective surgery can be less selective than suggested. As part of a prospective transregional research project the present study evaluated the outcome in memory and nonmemory functions, following two selective approaches: a combined temporal pole resection with amygdalohippocampectomy (TPR+) and transsylvian selective amygdalohippocampectomy (SAH). Methods: One year after surgery, cognitive outcomes of postoperatively seizure-free patients with mesial TLE and hippocampal sclerosis, who underwent either TPR+ (N = 35) or SAH (N = 62) in two German epilepsy centers (Bonn/Berlin), were compared. Results: Repeated measurement MANOVA and separate post hoc testing indicated a double dissociation of verbal/figural memory outcome as dependent on side and type of surgery. Verbal memory outcome was worse after left-sided operation, but especially for SAH, whereas figural memory outcome was worse after right-sided operation, preferentially for TPR+. Attention improved independent of side or type of surgery, and language functions showed some improvement after right-sided surgeries. Discussion: The results indicate a differential effect of left/right SAH versus TPR+ on material-specific memory insofar as transsylvian SAH appears to be favorable in right and TPR+ in left MTLE. The different outcomes are discussed in terms of a different surgical affection of the temporal pole and stem, and different roles of these structures for verbal and figural memory. [source]

Electrical Stimulation of the Hippocampal Epileptic Foci for Seizure Control: A Double-Blind, Long-Term Follow-Up Study

EPILEPSIA, Issue 10 2007
Ana Luisa Velasco
Summary:,Purpose: Our aim was to evaluate the safety and efficacy of electrical stimulation of the hippocampus in a long-term follow-up study, as well as its impact on memory performance in the treatment of patients with refractory mesial temporal lobe epilepsy. Methods: Nine patients were included. All had refractory partial complex seizures, some with secondary generalizations. All patients had a 3-month-baseline-seizure count, after which they underwent bilateral hippocampal diagnostic electrode implantation to establish focus laterality and location. Three patients had bilateral, and six, unilateral foci. Diagnostic electrodes were explanted and definitive Medtronic electrodes were implanted directed into the hippocampal foci. Position was confirmed with MRI and afterwards, the deep brain stimulation system internalized. Patients signed the informed consent approved by the Hospital's Ethics Committee and began a double-blind stimulation protocol. Patients attended a medical appointment every 3 months for seizure diary collection, deep brain stimulation system checkup, and neuropsychological testing. Results: Follow-up ranged from 18 months to 7 years. Patients were divided in two groups: five had normal MRIs and seizure reduction of >95%, while four had hippocampal sclerosis and seizure reduction of 50,70%. No patient had neuropsychological deterioration, nor did any patient show side effects. Three patients were explanted after 2 years due to skin erosion in the trajectory of the system. Conclusions: Electrical stimulation of the hippocampus provides a nonlesional method that improves seizure outcome without memory deterioration in patients with hippocampal epileptic foci. [source]

Long-term Prognosis and Psychosocial Outcomes after Surgery for MTLE

EPILEPSIA, Issue 12 2006
Sophie Dupont
Summary:,Purpose: To assess the seizure-freedom rates and self-perceived psychosocial changes associated with the long-term outcome of epilepsy surgery in patients with refractory medial temporal lobe epilepsy associated with hippocampal sclerosis. Methods: A standard questionnaire was given to 183 patients who underwent surgery between 1988 and 2004, and 110 were completed. Results: The mean duration of follow-up after surgery was 7 years, with a maximum of 17 years. The probability that patients were seizure-free after surgery was dependent on the definition of the seizure freedom. For the patients who were seizure-free since surgery (Engel's class Ia), the probability was 97.6% at 1 year after surgery, 85.2% at 2 years after surgery, 59.5% at 5 years after surgery, and 42.6% at 10 years after surgery. For the patients who still experienced rare disabling seizures after surgery but were seizure-free at least 1 year before the time of assessment, the probability was of 97.6% at 1 year after surgery, 95% at 2 years after surgery, 82.8% at 5 years after surgery, and 71.1% at 10 years after surgery. The psychosocial long-term outcome, as measured by indices of driving, employment, familial and social relationships, and marital status, was similar to the psychosocial short-term outcome. It did not depend on seizure freedom or on follow-up time interval and was not influenced statistically by seizure frequency in cases of persisting seizures. Most but not all patients noticed a substantial overall improvement in their psychosocial condition; 48% drove (increased by 7%), 47% improved (14% worsened) in their employment status, and 68% improved (5% worsened) in their familial and social relationships. Overall, 91% of patients were satisfied with the surgery, and 92% did not regret their decision. Conclusions: The results of this study suggest that temporal lobe surgery has real long-term benefits. Two specific conclusions emerge: (a) the long-term rates of freedom from seizure depend on how seizure freedom is defined, and (b) the psychosocial long-term outcome does not change dramatically over years and does not depend on seizure freedom. [source]

Decreased Dopamine D2/D3-Receptor Binding in Temporal Lobe Epilepsy: An [18F]Fallypride PET Study

EPILEPSIA, Issue 8 2006
Konrad J. Werhahn
Summary:,Purpose: Although animal data are suggestive, evidence for an alteration of the extrastriatal dopaminergic system in human focal epilepsy is missing. Methods: To quantify D2/D3-receptor density, we studied seven patients with temporal lobe epilepsy (TLE) and nine age-matched controls with positron emission tomography (PET) by using the high-affinity dopamine D2/D3-receptor ligand [18F]Fallypride ([18F]FP) suitable for imaging extrastriatal binding. TLE was defined by interictal and ictal video-EEG, magnetic resonance imaging (MRI), and [18F]fluorodeoxyglucose ([18F]FDG)-PET and was due to hippocampal sclerosis (HS), based on histology in all patients. Primary analysis was based on regions of interest (ROIs) defined on individual MRIs. For each patient, binding potential (BP) was calculated by using the simplified reference tissue model, and the epileptogenic was compared with the unaffected hemisphere in each ROI. To confirm the results, an additional voxel-based group analysis was performed by using statistical parametric mapping. Results: Compared with controls, [18F]FP BP was significantly decreased in the epileptogenic temporal lobe in all patients. On ROI analysis, this reduction was evident in areas surrounding the seizure-onset zone at the pole (,34.2%) and lateral aspects (,32.9%) of the temporal lobe. Although the hippocampus [18F]FDG uptake (,8.1%) and hippocampal MR volume (,35.1%) were significantly reduced, no significant decrease of [18F]FP BP was found. Reduction of [18F]FP BP did not correlate with hippocampal atrophy. Conclusions: D2/D3-receptor binding is reduced at the pole and in lateral aspects of the epileptogenic temporal lobe in patients with mesial TLE and HS. This area might correspond to "the irritative zone," indicating that D2/D3 receptors might play a specific role in the pathophysiology of mesial TLE. [source]

Ictal Brain Hyperperfusion Contralateral to Seizure Onset: The SPECT Mirror Image

EPILEPSIA, Issue 1 2006
Gilles Huberfeld
Summary:,Purpose: Ictal single-photon emission computed tomography (SPECT) may help localize the seizure-onset zone (SOZ) by detecting changes in regional cerebral blood flow induced by epileptic discharges. This imaging method also reveals hyperperfusions in areas of seizure propagation, including the hemisphere contralateral to the SOZ. We have studied the occurrence, the topography, and the clinical value of such contralateral ictal hyperperfusion areas (HPAs). Methods: We examined data from presurgical evaluations of 36 consecutive patients with pharmacoresistant partial epilepsy of various localizations. Ictal and interictal SPECT examinations were made with 99mTc-ECD, and the scans were processed for coregistration, normalization, subtraction, and merging with MRI images. Results: Contralateral HPAs were observed in 72% of the patients: 50% of mesiotemporal epilepsy cases with hippocampal sclerosis, 85.7% of the other mesiotemporal epilepsies, 85.7% of neocortical lateral temporal epilepsies, and 87.5% of extratemporal epilepsies. Contralateral HPAs were usually symmetrical to the SOZ, forming a mirror image, observed in 57.1% of the patients. They could be slightly asymmetrical in mesiotemporal epilepsies, perhaps because of the particular anatomic pathways linking temporal lobes. In neocortical epilepsies, they were located in the cortex homotopic to the SOZ. Conclusions: We show that the symmetrical nature of the mirror image usually does not disturb SPECT interpretation. It can confirm the location of the SOZ (11 patients) and even occasionally improve the precision of its definition (nine patients) by restraining several potential SOZ-related HPAs to a single one or by permitting a restricted localization of the SOZ in a large HPA. [source]

Prognostic Factors for the Surgery for Mesial Temporal Lobe Epilepsy: Longitudinal Analysis

EPILEPSIA, Issue 8 2005
Sang-Wuk Jeong
Summary:,Purpose: Determining long-term prognostic factors of surgery for mesial temporal lobe epilepsy (MTLE) is important for identifying ideal candidates and predicting the prognosis for individual patients. We tried to identify the prognostic factors of anterior temporal lobectomy (ATL) for MTLE with longitudinal multivariate analysis. Methods: Two hundred twenty-seven patients with MTLE were included in this study. The primary outcome variable was patient status 1,5 years after surgery: seizure free, or not. Clinical characteristics and recent diagnostic modalities were considered as prognostic factors. Univariate and standard multiple logistic-regression analysis for outcome at 1 and 5 years after surgery and the generalized estimation equation (GEE) model for longitudinal multiple logistic regression of the 5-year follow-up period were used. Results: The seizure-free rate at 1 year was 81.1% and decreased to 75.2% at 5 years after surgery. By the univariate or standard multiple logistic-regression analysis, age at surgery or hippocampal sclerosis on magnetic resonance imaging (MRI) ipsilateral to surgery was significant for the postsurgical outcome. However, the longitudinal analysis by the GEE model revealed that younger age at surgery [odds ratio (OR), 0.59; 95% confidence interval (CI), 0.43,0.81], absence of secondarily generalized tonic,clonic seizure (2°GTCS; OR, 0.45; 95% CI, 0.26,0.79), and hippocampal sclerosis on MRI (OR, 2.44; 95% CI, 1.11,5.26) were significant predictors of a good surgical outcome. Conclusions: Age at surgery, presence of 2°GTCS, and hippocampal sclerosis on MRI are independent prognostic factors for ATL in MTLE. These findings suggest that MTLE is a progressive disorder, and surgical outcome is better when early ATL is performed. [source]

Hippocampal Malformations Do Not Necessarily Evolve into Hippocampal Sclerosis

Correlation between 1H MRS and Memory before and after Surgery in Mesial Temporal Lobe Epilepsy with Hippocampal Sclerosis

Seizure Outcome after Temporal Lobectomy in Temporal Lobe Cortical Dysplasia

EPILEPSIA, Issue 11 2003
Teeradej Srikijvilaikul
Summary:,Purpose: To identify the temporal lobe cortical dysplasia (CD) histopathology classification subtype and determine the seizure outcome of patients who underwent temporal lobectomy with coincident CD. Methods: We reviewed the data of 28 patients with temporal lobe epilepsy who underwent surgery with pathologically verified CD at our institution from 1990 to 2000. The seizure outcome was assessed at a minimum of 1 year after surgery according to Engel's classification. Results: Of 28 patients who underwent surgery, nine (32.1%) had isolated CD, and 19 (67.9%) had CD and hippocampal sclerosis (CD&HS). Twenty-six (92.9%) patients had histopathology subtype Ia (architectural abnormalities). Twenty (71.4%) patients were seizure free (Engel class I). Favorable seizure outcome (Engel class I, II) was achieved in 26 (92.9%) patients. No difference in seizure outcome was noted between patients with CD and CD&HS. Conclusions: The most common histopathologic subtype in patients with temporal lobe CD is type Ia (architectural abnormalities). Temporal lobectomy in temporal lobe epilepsy patients with CD can achieve favorable seizure outcome. [source]

Neocortical Temporal FDG-PET Hypometabolism Correlates with Temporal Lobe Atrophy in Hippocampal Sclerosis Associated with Microscopic Cortical Dysplasia