Temporal Lobe

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John S. Duncan - One of the best experts on this subject based on the ideXlab platform.

  • Left Temporal Lobe language network connectivity in Temporal Lobe epilepsy
    Brain, 2018
    Co-Authors: Karin Trimmel, Andre Van Graan, Lorenzo Caciagli, A. Haag, Matthias J. Koepp, Pamela J. Thompson, John S. Duncan
    Abstract:

    Impairment of naming function is a critical problem for Temporal Lobe epilepsy patients, yet the neural correlates of the disruption of Temporal Lobe language networks are poorly understood. Using functional MRI, we investigated the activation and task-related functional connectivity of left Temporal Lobe language networks and their relation to clinical naming performance and disease characteristics. We studied 59 adult patients with Temporal Lobe epilepsy (35 left Temporal Lobe epilepsy) and 32 healthy controls with auditory and visual naming functional MRI tasks. Time series of activation maxima in the left posterior inferior Temporal Lobe were extracted to create a psychophysiological interaction regressor for subsequent seed-based whole-brain task-related functional connectivity analyses. Correlational analyses were performed to assess the association of functional MRI activation and functional connectivity with clinical naming scores, age of onset of epilepsy, and duration of epilepsy. Auditory naming elicited activation in the left posterior inferior Temporal gyrus and visual naming in the left fusiform gyrus across all groups. Activations in the left inferior Temporal gyrus, left thalamus and left supplementary motor region during auditory naming as well as left fusiform activations during picture naming correlated with better clinical naming performance. Functional connectivity analyses indicated coupling of left posterior inferior Temporal regions to bilateral anterior and posterior Temporal Lobe regions and the bilateral inferior precentral gyrus as well as contralateral occipital cortex. Stronger functional connectivity was associated with better clinical naming performance in all groups. In patients with left Temporal Lobe epilepsy only, functional connectivity increased with later age of onset of epilepsy and shorter disease duration. This suggests that onset of seizures early in life and prolonged disease duration lead to disrupted recruitment of Temporal Lobe networks ipsilateral to the seizure focus, which might account for naming deficits in Temporal Lobe epilepsy.

  • Imaging memory in Temporal Lobe epilepsy: predicting the effects of Temporal Lobe resection
    Brain, 2010
    Co-Authors: Silvia B. Bonelli, Matthias J. Koepp, Pamela J. Thompson, R Powell, Mahinda Yogarajah, Rebecca S. Samson, Mark R. Symms, John S. Duncan
    Abstract:

    Functional magnetic resonance imaging can demonstrate the functional anatomy of cognitive processes. In patients with refractory Temporal Lobe epilepsy, evaluation of preoperative verbal and visual memory function is important as anterior Temporal Lobe resections may result in material specific memory impairment, typically verbal memory decline following left and visual memory decline after right anterior Temporal Lobe resection. This study aimed to investigate reorganization of memory functions in Temporal Lobe epilepsy and to determine whether preoperative memory functional magnetic resonance imaging may predict memory changes following anterior Temporal Lobe resection. We studied 72 patients with unilateral medial Temporal Lobe epilepsy (41 left) and 20 healthy controls. A functional magnetic resonance imaging memory encoding paradigm for pictures, words and faces was used testing verbal and visual memory in a single scanning session on a 3T magnetic resonance imaging scanner. Fifty-four patients subsequently underwent left (29) or right (25) anterior Temporal Lobe resection. Verbal and design learning were assessed before and 4 months after surgery. Event-related functional magnetic resonance imaging analysis revealed that in left Temporal Lobe epilepsy, greater left hippocampal activation for word encoding correlated with better verbal memory. In right Temporal Lobe epilepsy, greater right hippocampal activation for face encoding correlated with better visual memory. In left Temporal Lobe epilepsy, greater left than right anterior hippocampal activation on word encoding correlated with greater verbal memory decline after left anterior Temporal Lobe resection, while greater left than right posterior hippocampal activation correlated with better postoperative verbal memory outcome. In right Temporal Lobe epilepsy, greater right than left anterior hippocampal functional magnetic resonance imaging activation on face encoding predicted greater visual memory decline after right anterior Temporal Lobe resection, while greater right than left posterior hippocampal activation correlated with better visual memory outcome. Stepwise linear regression identified asymmetry of activation for encoding words and faces in the ipsilateral anterior medial Temporal Lobe as strongest predictors for postoperative verbal and visual memory decline. Activation asymmetry, language lateralization and performance on preoperative neuropsychological tests predicted clinically significant verbal memory decline in all patients who underwent left anterior Temporal Lobe resection, but were less able to predict visual memory decline after right anterior Temporal Lobe resection. Preoperative memory functional magnetic resonance imaging was the strongest predictor of verbal and visual memory decline following anterior Temporal Lobe resection. Preoperatively, verbal and visual memory function utilized the damaged, ipsilateral hippocampus and also the contralateral hippocampus. Memory function in the ipsilateral posterior hippocampus may contribute to better preservation of memory after surgery.

  • Temporal Lobe sclerosis associated with hippocampal sclerosis in Temporal Lobe epilepsy: neuropathological features.
    Journal of Neuropathology and Experimental Neurology, 2009
    Co-Authors: Maria Thom, John S. Duncan, Sofia H Eriksson, Lillian Martinian, Luis O. Caboclo, Andrew W. Mcevoy, Sanjay M. Sisodiya
    Abstract:

    Widespread changes involving neocortical and mesial Temporal Lobe structures can be present in patients with Temporal Lobe epilepsy and hippocampal sclerosis. The incidence, pathology, and clinical significance of neocortical Temporal Lobe sclerosis (TLS) are not well characterized. We identified TLS in 30 of 272 surgically treated cases of hippocampal sclerosis. Temporal Lobe sclerosis was defined by variable reduction of neurons from cortical layers II/III and laminar gliosis; it was typically accompanied by additional architectural abnormalities of layer II, that is, abnormal neuronal orientation and aggregation. Quantitative analysis including tessellation methods for the distribution of layer II neurons supported these observations. In 40% of cases, there was a gradient of TLS with more severe involvement toward the Temporal pole, possibly signifying involvement of hippocampal projection pathways. There was a history of a febrile seizure as an initial precipitating injury in 73% of patients with TLS compared with 36% without TLS; no other clinical differences between TLS and non-TLS cases were identified. Temporal Lobe sclerosis was not evident preoperatively by neuroimaging. No obvious effect of TLS on seizure outcome was noted after Temporal Lobe resection; 73% became seizure-free at 2-year follow-up. In conclusion, approximately 11% of surgically treated hippocampal sclerosis is accompanied by TLS. Temporal Lobe sclerosis is likely an acquired process with accompanying reorganizational dysplasia and an extension of mesial Temporal sclerosis rather than a separate pathological entity.

  • Proton MR spectroscopy of metabolite concentrations in Temporal Lobe epilepsy and effect of Temporal Lobe resection.
    Epilepsy Research, 2009
    Co-Authors: Robert J Simister, Mary A Mclean, Gareth J Barker, John S. Duncan
    Abstract:

    Summary Purpose To use proton Magnetic Resonance Spectroscopy (MRS) to measure in vivo Temporal Lobe GABA and glutamate plus glutamine (GLX) concentrations in patients with Temporal Lobe epilepsy (TLE) attributable to unilateral hippocampal sclerosis (HS) before and following anterior Temporal Lobe resection (ATLR). Methods We obtained quantitative short echo time MRS in both Temporal Lobes of 15 controls and 16 patients with TLE and HS, and repeat spectra in 10 patients after ATLR. We measured the concentrations of N-acetyl aspartate + N-acetyl aspartyl-glutamate (NAAt), creatine plus phosphocreatine (Cr), and glutamate + glutamine (GLX) using a metabolite-nulled sequence designed to minimize macromolecule artifact. GABA concentrations were measured using a previously described double quantum filter. Results In patients with TLE, NAAt/Cr was reduced in ipsilateral and contralateral Temporal Lobes. No significant variation in GLX/Cr or GABA+/Cr was evident in any group although GABA+/Cr was highest in the ipsilateral Temporal Lobe in TLE. After ATLR there was a trend to normalization of NAAt/Cr in the contralateral Temporal Lobe but no change in individual metabolite concentrations, GLX/Cr or GABA+/Cr compared to pre-surgery levels. Discussion Temporal Lobe epilepsy was associated with bilateral reduction in NAAt/Cr but not significant abnormality in GABA+/Cr or GLX/Cr. Normalization of NAAt/Cr in the contralateral Temporal Lobe was seen following successful ATLR.

  • Proton MR spectroscopy of metabolite concentrations in Temporal Lobe epilepsy and effect of Temporal Lobe resection.
    Epilepsy research, 2008
    Co-Authors: Robert J Simister, Mary A Mclean, Gareth J Barker, John S. Duncan
    Abstract:

    To use proton Magnetic Resonance Spectroscopy (MRS) to measure in vivo Temporal Lobe GABA and glutamate plus glutamine (GLX) concentrations in patients with Temporal Lobe epilepsy (TLE) attributable to unilateral hippocampal sclerosis (HS) before and following anterior Temporal Lobe resection (ATLR). We obtained quantitative short echo time MRS in both Temporal Lobes of 15 controls and 16 patients with TLE and HS, and repeat spectra in 10 patients after ATLR. We measured the concentrations of N-acetyl aspartate+N-acetyl aspartyl-glutamate (NAAt), creatine plus phosphocreatine (Cr), and glutamate+glutamine (GLX) using a metabolite-nulled sequence designed to minimize macromolecule artifact. GABA concentrations were measured using a previously described double quantum filter. In patients with TLE, NAAt/Cr was reduced in ipsilateral and contralateral Temporal Lobes. No significant variation in GLX/Cr or GABA+/Cr was evident in any group although GABA+/Cr was highest in the ipsilateral Temporal Lobe in TLE. After ATLR there was a trend to normalization of NAAt/Cr in the contralateral Temporal Lobe but no change in individual metabolite concentrations, GLX/Cr or GABA+/Cr compared to pre-surgery levels. Temporal Lobe epilepsy was associated with bilateral reduction in NAAt/Cr but not significant abnormality in GABA+/Cr or GLX/Cr. Normalization of NAAt/Cr in the contralateral Temporal Lobe was seen following successful ATLR.

Margitta Seeck - One of the best experts on this subject based on the ideXlab platform.

  • Trajectories of brain remodeling in Temporal Lobe epilepsy
    Journal of Neurology, 2019
    Co-Authors: Elisabeth Roggenhofer, Margitta Seeck, Emiliano Santarnecchi, Sandrine Muller, Ferath Kherif, Roland Wiest, Bogdan Draganski
    Abstract:

    Temporal Lobe epilepsy has been usually associated with progressive brain atrophy due to neuronal cell loss. However, recent animal models demonstrated a dual effect of epileptic seizures with initial enhancement of hippocampal neurogenesis followed by abnormal astrocyte proliferation and neurogenesis depletion in the chronic stage. Our aim was to test for the hypothesized bidirectional pattern of epilepsy-associated brain remodeling in the context of the presence and absence of mesial Temporal Lobe sclerosis. We acquired MRIs from a large cohort of mesial Temporal Lobe epilepsy patients with or without hippocampus sclerosis on radiological examination. The statistical analysis tested explicitly for common and differential brain patterns between the two patients’ cohorts and healthy controls within the computational anatomy framework of voxel-based morphometry. The main effect of disease was associated with continuous hippocampus volume loss ipsilateral to the seizure onset zone in both Temporal Lobe epilepsy cohorts. The post hoc simple effects tests demonstrated bilateral hippocampus volume increase in the early epilepsy stages in patients without hippocampus sclerosis. Early age of onset and longer disease duration correlated with volume decrease in the ipsilateral hippocampus. Our findings of seizure-induced hippocampal remodeling are associated with specific patterns of mesial Temporal Lobe atrophy that are modulated by individual clinical phenotype features. Directionality of hippocampus volume changes strongly depends on the chronicity of disease. Specific anatomy differences represent a snapshot within a progressive continuum of seizure-induced structural remodeling.

  • Contralateral medial Temporal Lobe damage in right but not left Temporal Lobe epilepsy: a (1)H magnetic resonance spectroscopy study.
    Journal of Neurology Neurosurgery and Psychiatry, 2003
    Co-Authors: Frederic Zubler, Margitta Seeck, Theodor Landis, F Henry, F Lazeyras
    Abstract:

    Background: Proton magnetic resonance spectroscopy (MRS) of the hippocampus is useful in lateralising the epileptic focus in Temporal Lobe epilepsy for subsequent surgical resection. Previous studies have reported abnormal contralateral MRS values in up to 50% of the patients. Objective: To identify the contributing factors to contralateral damage, as determined by MRS, and its extension in patients with Temporal Lobe epilepsy. Methods: Single voxel MRS was carried out in the hippocampus and lateral Temporal neocortex of both hemispheres in 13 patients with left Temporal Lobe epilepsy (LTLE) and 16 patients with right Temporal Lobe epilepsy (RTLE). All patients had mesial Temporal Lobe epilepsy with hippocampal sclerosis. Controls were 21 healthy volunteers of comparable age. Results: Consistent with previous studies, the NAA/(Cho+Cr) ratio was abnormally low in the hippocampus ipsilateral to the focus (p < 0.0001), and there were lower values in both patient groups in the ipsilateral Temporal neocortex (p < 0.0001). Patients with RTLE had left hippocampal MRS anomalies (p = 0.0018), whereas the right hippocampus seemed to be undamaged in LTLE patients. Conclusions: Unilateral mesial Temporal Lobe epilepsy is associated with widespread metabolic abnormalities which involve contralateral mesial and neocortical Temporal Lobe structures. These abnormalities appear to be more pronounced in patients with RTLE.

Yi Shi - One of the best experts on this subject based on the ideXlab platform.

  • Diagnosis and surgical treatment of Temporal Lobe epilepsy.
    Chinese Medical Journal, 2001
    Co-Authors: Xiang Gao, Jiang C, Yi Shi
    Abstract:

    OBJECTIVE To discuss the diagnosis and surgical treatment of Temporal Lobe epilepsy. METHODS From 1996 to 1998, 36 patients presenting with medically intractable Temporal Lobe epilepsy were identified by EEG and MR, including volumetric MR, for hippocampal formation. Among them, 16 patients underwent anterior Temporal Lobectomy, while 20 patients accepted selective amygdalohippocampectomy. The results of surgical operation and follow-up are analyzed. RESULTS With respect to seizure outcome, all patients benefited from surgery. The surgical results were satisfactory in 24 cases, notable in 11 cases, and good in 1 case, and there were no complications. CONCLUSION MR is beneficial for the localization of epileptic foci. Surgery is an effective method for the treatment of Temporal Lobe epilepsy; selective amygdalohippocampectomy is the first choice for medial Temporal Lobe epilepsy. The transzygmatic-Temporal Lobe base approach presented in this study improved the safety of the surgery.

  • Diagnosis and surgical treatment of Temporal Lobe epilepsy
    Chinese journal of surgery, 2000
    Co-Authors: Xiang Gao, Jiang C, Yi Shi
    Abstract:

    OBJECTIVE To discuss the diagnosis and surgical treatment of Temporal Lobe epilepsy. METHODS From 1995 to 1998, 30 patients with intractable mesial Temporal Lobe epilepsy were identified by EEG and MR. Among them, 15 patients underwent anterior Temporal Lobectomy, while another 15 patients accepted selective amygdalahippocampectomy. The results of operation and follow-up were analyzed. RESULTS As to seizure outcome, all patients were benefited from surgery. Surgical result was satisfactory in 18 patients, notable in 11, and good in 1. There was no complication. CONCLUSIONS MR is beneficial for the localization of epileptic foci. Operation is an effective way for the treatment of Temporal Lobe epilepsy. Selective amygdalohippocampus is the first choice for medial Temporal Lobe epilepsy. Transzygmatic-Temporal Lobe base approach improves the safety of operation.

Robert J Simister - One of the best experts on this subject based on the ideXlab platform.

  • Proton MR spectroscopy of metabolite concentrations in Temporal Lobe epilepsy and effect of Temporal Lobe resection.
    Epilepsy Research, 2009
    Co-Authors: Robert J Simister, Mary A Mclean, Gareth J Barker, John S. Duncan
    Abstract:

    Summary Purpose To use proton Magnetic Resonance Spectroscopy (MRS) to measure in vivo Temporal Lobe GABA and glutamate plus glutamine (GLX) concentrations in patients with Temporal Lobe epilepsy (TLE) attributable to unilateral hippocampal sclerosis (HS) before and following anterior Temporal Lobe resection (ATLR). Methods We obtained quantitative short echo time MRS in both Temporal Lobes of 15 controls and 16 patients with TLE and HS, and repeat spectra in 10 patients after ATLR. We measured the concentrations of N-acetyl aspartate + N-acetyl aspartyl-glutamate (NAAt), creatine plus phosphocreatine (Cr), and glutamate + glutamine (GLX) using a metabolite-nulled sequence designed to minimize macromolecule artifact. GABA concentrations were measured using a previously described double quantum filter. Results In patients with TLE, NAAt/Cr was reduced in ipsilateral and contralateral Temporal Lobes. No significant variation in GLX/Cr or GABA+/Cr was evident in any group although GABA+/Cr was highest in the ipsilateral Temporal Lobe in TLE. After ATLR there was a trend to normalization of NAAt/Cr in the contralateral Temporal Lobe but no change in individual metabolite concentrations, GLX/Cr or GABA+/Cr compared to pre-surgery levels. Discussion Temporal Lobe epilepsy was associated with bilateral reduction in NAAt/Cr but not significant abnormality in GABA+/Cr or GLX/Cr. Normalization of NAAt/Cr in the contralateral Temporal Lobe was seen following successful ATLR.

  • Proton MR spectroscopy of metabolite concentrations in Temporal Lobe epilepsy and effect of Temporal Lobe resection.
    Epilepsy research, 2008
    Co-Authors: Robert J Simister, Mary A Mclean, Gareth J Barker, John S. Duncan
    Abstract:

    To use proton Magnetic Resonance Spectroscopy (MRS) to measure in vivo Temporal Lobe GABA and glutamate plus glutamine (GLX) concentrations in patients with Temporal Lobe epilepsy (TLE) attributable to unilateral hippocampal sclerosis (HS) before and following anterior Temporal Lobe resection (ATLR). We obtained quantitative short echo time MRS in both Temporal Lobes of 15 controls and 16 patients with TLE and HS, and repeat spectra in 10 patients after ATLR. We measured the concentrations of N-acetyl aspartate+N-acetyl aspartyl-glutamate (NAAt), creatine plus phosphocreatine (Cr), and glutamate+glutamine (GLX) using a metabolite-nulled sequence designed to minimize macromolecule artifact. GABA concentrations were measured using a previously described double quantum filter. In patients with TLE, NAAt/Cr was reduced in ipsilateral and contralateral Temporal Lobes. No significant variation in GLX/Cr or GABA+/Cr was evident in any group although GABA+/Cr was highest in the ipsilateral Temporal Lobe in TLE. After ATLR there was a trend to normalization of NAAt/Cr in the contralateral Temporal Lobe but no change in individual metabolite concentrations, GLX/Cr or GABA+/Cr compared to pre-surgery levels. Temporal Lobe epilepsy was associated with bilateral reduction in NAAt/Cr but not significant abnormality in GABA+/Cr or GLX/Cr. Normalization of NAAt/Cr in the contralateral Temporal Lobe was seen following successful ATLR.

Fernando Cendes - One of the best experts on this subject based on the ideXlab platform.

  • Does resection of the medial Temporal Lobe improve the outcome of Temporal Lobe epilepsy surgery
    Epilepsia, 2007
    Co-Authors: Leonardo Bonilha, Chris Rorden, Clarissa L. Yasuda, Helder Tedeschi, Evandro De Oliveira, Fernando Cendes
    Abstract:

    Summary: Purpose: Surgical removal of the hippocampus is the standard of care of patients with drug-resistant medial Temporal Lobe epilepsy (MTLE). The procedure carries a success rate of ∼75%, but the reasons that some patients fail to achieve seizure control after surgery remain inexplicable. The question of whether the resection of medial Temporal Lobe structures in addition to the hippocampus would influence the surgical outcome in patients with MTLE was examined. Methods: We conducted voxel-based statistical analyses of postoperative high-resolution MRI of MTLE patients who underwent anteromedial Temporal resection. We applied a cost function transformation of the resection maps for each patient to a common set of spatial coordinates, and we analyzed the contribution of histologically distinct segments of the medial Temporal Lobe cortex to the surgical outcome. We also performed a voxel-wise mapping of surgical outcome to the Temporal Lobe. Results: We observed that the extent of hippocampal removal was associated with better outcomes. However, when the resection of the hippocampus was combined with the resection of the medial Temporal Lobe, specifically the entorhinal cortex, a greater likelihood of higher seizure control after surgery was found. Conclusions: Based on this finding, it is possible that the efficiency of the surgical treatment of MTLE can be improved by adjusting the procedure to include the resection of the entorhinal cortex, in addition to the resection of the hippocampus.

  • Medial Temporal Lobe atrophy in patients with refractory Temporal Lobe epilepsy.
    Journal of Neurology Neurosurgery and Psychiatry, 2003
    Co-Authors: Leonardo Bonilha, Eliane Kobayashi, Chris Rorden, Fernando Cendes
    Abstract:

    Objective: The objective of this study was to assess the volumes of medial Temporal Lobe structures using high resolution magnetic resonance images from patients with chronic refractory medial Temporal Lobe epilepsy (MTLE). Methods: We studied 30 healthy subjects, and 25 patients with drug refractory MTLE and unilateral hippocampal atrophy (HA). We used T1 magnetic resonance images with 1 mm isotropic voxels, and applied a field non-homogeneity correction and a linear stereotaxic transformation into a standard space. The structures of interest are the entorhinal cortex, perirhinal cortex, parahippocampal cortex, temporopolar cortex, hippocampus, and amygdala. Structures were identified by visual examination of the coronal, sagittal, and axial planes. The threshold of statistical significance was set to p