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Medial Temporal Lobe Epilepsy (medial + temporal_lobe_epilepsy)

Distribution by Scientific Domains

Medical Sciences	71%

Selected Abstracts

T2-Weighted and T2 Relaxometry Images in Patients with Medial Temporal Lobe Epilepsy

JOURNAL OF NEUROIMAGING, Issue 3 2006
Ana Carolina Coan MD
ABSTRACT Purpose. Quantification of increased T2-weighted MRI signal that is associated with hippocampal sclerosis (HS) can be performed through (1) mean of hippocampal signal in single-echo T2 MRI and (2) hippocampal T2 relaxometry. It is not clear whether these two techniques are equivalent. In this study, we compare the hippocampal signal, detected by single-echo T2 quantification and by T2 relaxometry, in patients with medial temporal lobe epilepsy (MTLE). Methods. We studied magnetic resonance images from 50 MTLE patients and 15 healthy subjects. We compared the quantification of a T2 signal from single echo images to T2 relaxometry, both obtained from a manually traced region of interest (ROI) in coronal slices involving the whole hippocampus. Repeated measures ANOVA was used to evaluate the differences in the distribution of the Z -scores from single-echo T2 quantification and T2 relaxometry within subjects. Results. We observed a significant difference between the measurements obtained from single-echo T2 quantification and T2 relaxometry (P < .001). Measurements from head, body, and tail of the hippocampus were different (P=.04), with a significant interaction between anatomic location and type of measurement used (P= .008). Post hoc paired comparisons revealed that T2 relaxometry yielded greater Z -scores for the body (P= .002) and tail (P < .0001). Conclusions. For each subject with MTLE, T2 relaxometry was able to detect a higher signal in the body and tail of the hippocampus compared to single-echo T2. This is a possible indicator that T2 relaxometry is more sensitive in detecting T2 abnormalities within the body and tail of the hippocampus in patients with MTLE. [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]

Epileptogenicity of Supratentorial Medullary Venous Malformation

EPILEPSIA, Issue 2 2006
Takato Morioka
Summary:,Purpose: The purpose of this study was to evaluate the epileptogenicity of supratentorial medullary venous malformation (MVM). Special consideration was given to any associations with intracerebral hemorrhage with or without other vascular malformations, including cavernous angioma (CA). Methods: In total, 10 patients with angiographically or histologically verified MVMs were examined. The patients were divided into two groups with or without intracerebral hemorrhage, and their clinical, neuroradiologic, and interictal and ictal EEG findings were reviewed retrospectively. Results: Although three of five patients in the nonhemorrhagic group had epilepsy, no topographic concordance was found between the MVM location and the EEG focus. On the contrary, in four of five patients in the hemorrhagic group, epilepsy developed, and topographic concordance between the hemorrhagic MVM location and the EEG focus was noted. One patient with a hemorrhagic MVM and an associated CA in the hippocampus had electroclinical pictures of intractable medial temporal lobe epilepsy on this side. Conclusions: Although a supratentorial MVM itself is not epileptogenic, the development of an intracerebral hemorrhage may cause epilepsy. In particular, an associated CA may be highly epileptogenic. [source]

Functional MRI Predicts Memory Performance after Right Mesiotemporal Epilepsy Surgery

EPILEPSIA, Issue 2 2005
Jozsef Janszky
Summary:,Purpose: Anterior temporal lobe resection (ATR) is a treatment option in drug-resistant epilepsy. An important risk of ATR is loss of memory because mesiotemporal structures contribute substantially to memory function. We investigated whether memory-activated functional MRI (fMRI) can predict postoperative memory loss after anterior temporal lobectomy in right-sided medial temporal lobe epilepsy (MTLE). Methods: We included 16 patients (10 women) aged 16,54 years. The mean age at epilepsy onset was 12.5 years (range, 1,26 years). The patients' mean Wechsler IQ score was 95.2 (range, 62,125). The activation condition of fMRI consisted of retrieval from long-term memory induced by self-paced performance of an imaginative walk. All but one patient had left-sided speech dominance according to speech-activated fMRI. Outside the scanner, we evaluated the pre- and postoperative visual memory retention by using Rey Visual Design Learning Test. Results: We found a correlation between the preoperative asymmetry index of memory- fMRI and the change between pre- and postsurgical measures of memory retention. Reduced activation of the mesiotemporal region ipsilateral to the epileptogenic region correlated with a favorable memory outcome after right-sided ATR. Conclusions: In light of the postoperative results, the theoretical implication of our study is that fMRI based on a simple introspective retrieval task measures memory functions. The main clinical implication of our study is that memory- fMRI might replace the invasive Wada test in MTLE by using a simple fMRI paradigm. Predictive power, however, will be studied in larger patient samples. Other studies are required for left-sided MTLE and neocortical epilepsies to assess the clinical usefulness of memory- fMRI. [source]

Amygdala damage affects event-related potentials for fearful faces at specific time windows

HUMAN BRAIN MAPPING, Issue 7 2010
Pia Rotshtein
Abstract The amygdala is known to influence processing of threat-related stimuli in distant brain regions, including visual cortex. The time-course of these distant influences is unknown, although this information is important for resolving debates over likely pathways mediating an apparent rapidity in emotional processing. To address this, we recorded event-related potentials (ERPs) to seen fearful face expressions, in preoperative patients with medial temporal lobe epilepsy who had varying degrees of amygdala pathology, plus healthy volunteers. We found that amygdala damage diminished ERPs for fearful versus neutral faces within the P1 time-range, ,100,150 ms, and for a later component at ,500,600 ms. Individual severity of amygdala damage determined the magnitude of both these effects, consistent with a causal amygdala role. By contrast, amygdala damage did not affect explicit perception of fearful expressions nor a distinct emotional ERP effect at 150,250 ms. These results demonstrate two distinct time-points at which the amygdala influences fear processing. The data also demonstrate that while not all aspects of expression processing are disrupted by amygdala damage, there is a crucial impact on an early P1 component. These findings are consistent with the existence of multiple processing stages or routes for fearful faces that vary in their dependence on amygdala function. Hum Brain Mapp, 2010. © 2009 Wiley-Liss, Inc. [source]

Decreased basal fMRI functional connectivity in epileptogenic networks and contralateral compensatory mechanisms

HUMAN BRAIN MAPPING, Issue 5 2009
Gaelle Bettus
Abstract A better understanding of interstructure relationship sustaining drug-resistant epileptogenic networks is crucial for surgical perspective and to better understand the consequences of epileptic processes on cognitive functions. We used resting-state fMRI to study basal functional connectivity within temporal lobes in medial temporal lobe epilepsy (MTLE) during interictal period. Two hundred consecutive single-shot GE-EPI acquisitions were acquired in 37 right-handed subjects (26 controls, eight patients presenting with left and three patients with right MTLE). For each hemisphere, normalized correlation coefficients were computed between pairs of time-course signals extracted from five regions involved in MTLE epileptogenic networks (Brodmann area 38, amygdala, entorhinal cortex (EC), anterior hippocampus (AntHip), and posterior hippocampus (PostHip)). In controls, an asymmetry was present with a global higher connectivity in the left temporal lobe. Relative to controls, the left MTLE group showed disruption of the left EC-AntHip link, and a trend of decreased connectivity of the left AntHip-PostHip link. In contrast, a trend of increased connectivity of the right AntHip-PostHip link was observed and was positively correlated to memory performance. At the individual level, seven out of the eight left MTLE patients showed decreased or disrupted functional connectivity. In this group, four patients with left TLE showed increased basal functional connectivity restricted to the right temporal lobe spared by seizures onset. A reverse pattern was observed at the individual level for patients with right TLE. This is the first demonstration of decreased basal functional connectivity within epileptogenic networks with concomitant contralateral increased connectivity possibly reflecting compensatory mechanisms. Hum Brain Mapp 2009. © 2008 Wiley-Liss, Inc. [source]