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At least 19 recordsLinked to original sources
PubMed2005

The effect of risperidone on metabolite measures in the frontal lobe, temporal lobe, and thalamus in schizophrenic patients. A proton magnetic resonance spectroscopy (1H MRS).

OBJECTIVE: The aim of the study was the evaluation of risperidone effect on metabolite measures in the frontal lobe, temporal lobe and thalamus in schizophrenic patients on the basis of proton magnetic resonance spectroscopy ( (1)H MRS). METHODS: A group of 14 patients with the diagnosis of schizophrenia, according to DSM-IV, were examined in the study. The patients were examined twice, once after a period of at least 7 days without neuroleptics and for the second time at least 4 weeks after stable risperidone doses. RESULTS: The significant differences in the metabolite levels before and after the treatment were observed only in thalamus: an increase in myoinositol (mI) and N-acetylaspartate (NAA) levels. Positive symptoms before the treatment correlated positively with NAA level in the frontal lobes and negatively in the temporal lobes. Negative symptoms before the treatment correlated positively with Glx (a common signal for GABA, glutamine and glutamate) level in the temporal lobes. CONCLUSION: Our results seem to confirm the influence of risperidone on the brain metabolism, specifically in the region of thalamus.

Adult↗
PubMed2005

Microdialysis of the lateral and medial temporal lobe during temporal lobe epilepsy surgery.

BACKGROUND: This study was undertaken to establish whether, in temporal lobe epilepsy (TLE), there are relative differences between the lateral and ipsilateral medial temporal lobe in the extracellular levels of 3 of the human brain's major neuroactive amino acids. METHODS: Seven generally anesthetized patients with TLE undergoing anatomically standardized resective surgery had at operation microdialysis catheters inserted within the middle temporal gyrus (ie, lateral temporal lobe) and anterior hippocampus (ie, medial temporal lobe). Surface electrocorticography (ECoG) recordings were also obtained. Samples of 10-minute dialysate were quantified for glutamate, aspartate, and gamma-aminobutyric acid (GABA) using high-performance liquid chromatography; corresponding ECoG data were assessed for epileptiform activity. Where available, resection tissue was subjected to histopathological analysis. RESULTS: The ratio of mean "sample 3" dialysate levels of glutamate, aspartate, and GABA was approximately 20:2:1, respectively, in both the minimally epileptiform lateral (n = 7) and medial (n = 5) temporal lobe; between the 2 sets of samples, these levels were not significantly different (P > 0.05 for each amino acid studied). From the vigorously epileptiform medial temporal lobe of 2 patients, sample 3 dialysate levels of the excitatory amino acids glutamate and aspartate were found in considerably greater concentrations (between 15- and 37-fold) with correspondingly less dramatic increases of the inhibitory amino acid GABA (more than 11- and 13-fold). Laterally resected tissue (obtained in 3 cases) did not demonstrate significant cortical or subcortical abnormalities; medial resection tissue from all patients demonstrated, in varying degrees, hippocampal sclerosis. CONCLUSIONS: In the absence of significant tissue hyperexcitability, despite known differences in local cellular and/or histopathological architecture, the extracellular relationship among glutamate, aspartate, and GABA is not dissimilar in both the lateral and ipsilateral medial temporal lobe of TLE patients. Considerable disparity in dialysate levels recovered (eg, from the vigorously epileptiform medial temporal lobe) may be related to the functional (ie, hyperexcitable) status of the sampled tissue.

Action Potentials↗
PubMed1998

Morphometric analysis of the temporal lobe in temporal lobe epilepsy.

PURPOSE: Using high-resolution magnetic resonance imaging (MRI), we examined the temporal neocortex and the underlying white matter in patients with unilateral temporal lobe epilepsy (TLE) and in control subjects. METHODS: The images of 27 patients and 42 control subjects were registered into stereotaxic space, corrected for image intensity inhomogeneity, and automatically segmented into gray matter, white matter, and cerebrospinal fluid (CSF) over a predetermined extent of the temporal lobe. The surface between the gray matter and CSF was extracted, indices of curvature (IOC) of the surface were calculated, and a frequency histogram of the IOC was obtained. RESULTS: There was significant bilateral reduction in the total volume of the temporal lobe and in the volume of gray matter. White matter volume was significantly reduced only in the temporal lobe ipsilateral to the seizure focus. There were significant changes in the position and amplitude of peaks in the frequency histogram of the IOC. CONCLUSIONS: The volume of gray matter was negatively correlated with duration of epilepsy, suggesting that neocortical changes may be a consequence of seizures. Changes in the frequency histogram of the IOC suggested an additional alteration in the surface morphology of the temporal lobe in TLE, possibly related to sulcal widening.

Adolescent↗
PubMed2003

Evidence of neuronal injury outside the medial temporal lobe in temporal lobe epilepsy: N-acetylaspartate concentration reductions detected with multisection proton MR spectroscopic imaging--initial experience.

PURPOSE: To determine whether magnetic resonance (MR) spectroscopic imaging reveals metabolic changes, especially decreased N-acetylaspartate (NAA) concentrations outside the medial temporal lobe in patients with mesial temporal lobe epilepsy (TLE), consistent with neuropathologic findings of extratemporal neuronal impairment. MATERIALS AND METHODS: Eleven patients with mesial TLE and 13 control subjects were examined with multisection MR spectroscopic imaging. Three MR spectroscopic imaging sections were acquired. Thirteen brain regions in each hemisphere and the midbrain were analyzed in each patient, and the NAA to creatine-phosphocreatine (Cr) plus choline-containing compounds (Ch) (NAA/[Cr + Ch]) ratios were determined. In addition, hemispheric and whole-brain values were calculated and statistically analyzed. RESULTS: The NAA/(Cr + Ch) ratio in the ipsilateral hippocampus was significantly reduced, compared with that in the contralateral hippocampus (P <.002) and compared with that in control subjects (P <.03), confirming findings in previous studies. In patients, whole-brain NAA/(Cr + Ch) ratio outside the hippocampus was significantly lower than that in control subjects (P <.002). For the ipsilateral hemisphere in patients, NAA/(Cr + Ch) ratio was significantly lower than that in control subjects (P <.0002). Comparisons between individual brain regions revealed trends toward lower NAA/(Cr + Ch) ratios in many areas of the ipsilateral and, to a lesser extent, the contralateral hemisphere outside the hippocampus and temporal lobe, suggesting diffuse impairment. CONCLUSION: Results suggest that repeated seizure activity damages neurons outside of the seizure focus.

Adult↗
PubMed1996

[Relationship between anatomic lesions of the temporal lobe and temporal lobe epilepsy].

A structural lesion of the brain is a frequent finding in intractable partial epileptic patients. We analyse anatomo-electro-clinical characteristics of 58 patients in which MR showed a lesion inside the temporal lobe. They are 29 males and 29 females with a mean age at surgery of 23.5 +/- 10.7 years (2.6-45.9). The mean epilepsy duration is of 13.4 +/- 8 years (1.3-35.5), with a mean seizure frequency of 28.7 +/- 43.6 per month, with a great inter-individual variability (from 3 per month to 15 a day). The minimum follow-up is 3.5 years. A video-EEG monitoring was performed in 21 cases, while a stereo-EEG investigation was judged mandatory in 26. On the basis of anatomo-electro-clinical correlations and of the results of presurgical investigations, the epileptogenic area was proved to be temporal in 49 cases, temporal but controlateral to the lesion in 1, and at least bilobar in 8 patients.

Adolescent↗
PubMed2001

Extrahippocampal temporal lobe atrophy in temporal lobe epilepsy and mesial temporal sclerosis.

Visual inspection and volumetric analysis of MRIs allow mesial temporal sclerosis (MTS) to be reliably identified in patients with temporal lobe epilepsy. The presence of unilateral MTS ipsilateral to the side of habitual seizure onset is an indicator for the prognosis of good outcome after temporal lobe resection. There is evidence to suggest that widespread temporal lobe pathology, leading to atrophy, may be associated with MTS and such abnormal tissue may play an important role in epileptogenesis. We have analysed quantitatively the volumes of the mesial and lateral temporal lobe substructures in MRIs from 62 patients with intractable mesial temporal lobe epilepsy and in 20 normal controls. We found significant atrophy in these structures in patients, ranging from 8.3 to 18.4% compared with controls. The degree of atrophy in the extrahippocampal structures correlated with the degree of hippocampal atrophy, suggesting that a common process may be responsible. There was no correlation between the degree of atrophy in the extrahippocampal structures and the duration of epilepsy, a history of febrile convulsions or of generalized seizures. These findings suggest that there may be widespread pathological abnormalities in the temporal lobe associated with MTS. The importance of extrahippocampal atrophy to surgical outcome and whether it occurs in temporal lobe epilepsy not associated with MTS remain to be investigated.

Adult↗
PubMed1993

Anatomic temporal lobe resections for temporal lobe epilepsy.

Temporal lobe epilepsy is not a single clinicopathologic entity but a group of syndromes requiring different surgical solutions. Anatomic resections planned for the treatment of these syndromes are aimed at pathologic substrates minimizing ablation of normal tissue. Most of these procedures involve mesial and lateral temporal resections. The syndrome of mesial temporal sclerosis should be treated with resection aimed at hippocampus and the PHG, including entorhinal cortex, and at part of the amygdala. Improvement in diagnostic methods and refinement of anatomic surgical procedures that maximize resection of hippocampus resulted in excellent outcome in the treatment of patients with this syndrome. Mass lesions in patients with intractable seizures should be resected with some surrounding margins, but additional clinical studies will be required to determine the role of anatomic resections, including hippocampectomy, in the treatment of these patients. Extrahippocampal temporal lobe epilepsy is the most difficult to evaluate and treat. Tailored individualized resections based on acute or chronic EEG recordings may be required until and if discrete anatomically based syndromes can be identified in this patient population.

Epilepsy, Temporal Lobe↗
PubMed1996

Double dissociations of memory and executive functions in working memory tasks following frontal lobe excisions, temporal lobe excisions or amygdalo-hippocampectomy in man.

Thirty-two neurosurgical patients with unilateral or bilateral frontal lobe excisions, 41 patients with unilateral temporal lobe lesions and 19 patients who had undergone unilateral amygdalo-hippocampectomy were compared with matched controls on a computerized test of spatial working memory. A significant deficit was observed in the frontal lobe group, even at the least challenging level of task difficulty and this impairment was found to relate to the inefficient use of a particular searching strategy shown to improve performance on this task. In contrast, deficits in the temporal lobe group and the amygdalo-hippocampectomy group were only observed at the most difficult level of the task and in neither group could the deficit be related to the inefficient use of any particular searching strategy. In a follow-up study, the three patient groups were compared on analogous computerized tests of visual and verbal working memory. No deficits were observed in the frontal lobe group. By comparison, both the temporal lobe patients and the amygdalo-hippocampectomy group were significantly impaired in the visual working memory condition but not in the verbal working memory condition. These deficits were clearly evident at all levels of task difficulty and were not related to any particular searching strategy. The data are discussed in terms of the relative contributions of "executive' and "mnemonic' mechanisms to the contrasting, material dependent deficits observed in the frontal and temporal lobe groups.

Adult↗
PubMed1997

Changes in regional cerebral blood flow beyond the temporal lobe in unilateral temporal lobe epilepsy.

PURPOSE: Single photon emission computed tomography (SPECT) is widely used to evaluate functional abnormalities during the epileptic event. Changes in regional cerebral blood flow (rCBF) are well defined in patients with temporal lobe epilepsy (TLE) undergoing surgical resection. Nonetheless, the interpretation of ictal abnormalities in CBF beyond the temporal lobes has not been carefully addressed. METHODS: We assessed 4 patients with pathologically proven unilateral TLE who had significant ipsilateral frontal hypoperfusion in ictal studies with no other abnormalities but chronic epilepsy accounting for such findings. Patients were assessed as candidates for surgery by interictal EEG, neuropsychological studies, brain magnetic resonance imaging, scalp electrode video-EEG monitoring, and ictal SPECT. RESULTS: Characteristic hyperperfusion was evident over the temporal lobe ipsilateral to the EEG focus, with significant hypoperfusion over the frontal region in 3 patients. In patient 4, frontal hypoperfusion was not statistically significant. CONCLUSIONS: SPECT demonstrated relative rCBF changes beyond the epileptogenic zone in unilateral TLE. Our findings provide further insight into the pathophysiological changes underlying this condition.

Adult↗
PubMed1991

Extra-dimensional versus intra-dimensional set shifting performance following frontal lobe excisions, temporal lobe excisions or amygdalo-hippocampectomy in man.

Attentional "set" shifting was assessed in a group of 20 neurosurgical patients with localized excisions of the frontal lobes, a group of 20 patients with unilateral temporal lobe lesions and a group of 11 patients who had undergone amygdalo-hippocampus removal. These three patient groups were compared with groups of both young (age-matched) and elderly normal control volunteers on a computerized test of visual discrimination learning involving both an intra- and an extra-dimensional shift. The frontal lobe group were selectively impaired in their ability to shift response set to a previously irrelevant dimension but not to shift attention to new exemplars of a previously relevant dimension. A similar pattern was observed in the elderly group of normal control volunteers. By comparison, both the temporal lobe patients and the amygdalo-hippocampectomy patients were unimpaired in their ability to perform either shift, although both groups had significantly prolonged selection latencies at the extra-dimensional shift stage of the task. These data are compared to previous findings from patients with idiopathic Parkinson's disease and are discussed in terms of a specific attentional set shifting deficit following frontal lobe damage.

Adult↗
PubMed2006

[How do the temporal lobes communicate in medial temporal lobe seizures?].

INTRODUCTION: Spatial and temporal patterns of the spread of partial epileptic seizures depend on the site from which they originate. Characterising seizure propagation patterns may help to better define the seizure focus. In medial temporal lobe epilepsies, seizure propagation to the contralateral temporal lobe is especially studied. STATE OF THE ART: Intracranial EEG records permit more precise definition of patterns of contralateral propagation in medial temporal lobe epilepsies. Several pathways have been implicated, sometimes differently in distinct studies, in propagation to the contralateral temporal lobe: the three commissures (the corpus callosum, the ventral hippocampal commissure and the anterior commissure, which link the temporal lobes) and an indirect circuit via the frontal lobes. Delays measured for contralateral propagation of a seizure of temporo-limbic origin vary significantly around a mean value of about 30 seconds. This slow spread may depend in part on the relatively small size of human commissural projections from the amygdalo-hippocampal formation, which largely originate in the presubiculum. However, a larger commissural projection pathway originates in the paralimbic medial temporal lobe and electrical stimulation of the anterior perirhinal cortex can induce contralateral epileptic discharges with delays as short as 100 ms (Adam et al., 2004). Thus, seizure activity emerging from anterior paralimbic regions can propagate rapidly to the contralateral medial temporal lobe via the anterior commissure. PERSPECTIVES: While the propagation of medial temporal lobe seizures is still debated, further studies are merited since the extent and speed of spread governs the electro-clinical semiology of seizures and our ability to identify their initiation site. CONCLUSIONS: We review anatomical (Demeter et al., 1990) and neurophysiological (Wilson et al., 1990) data for a dual inter-temporal propagation of medial temporal lobe seizures at different speeds and via different pathways.

Brain Mapping↗
PubMed1995

Developmental abnormalities of the medial temporal lobe in patients with temporal lobe epilepsy.

PURPOSE: To evaluate MR temporal lobe malformations and their frequency in patients with temporal lobe epilepsy. METHODS: Two hundred twenty-two consecutive adult patients with temporal lobe epilepsy of varying severity were investigated with 1.0-T or 1.5-T MR units using three-dimensional T1-weighted acquisition protocol. RESULTS: Sixteen patients (7.2%) presented with malformations of the temporal lobe. Four patterns of malformations were encountered: (a) heterotopia (n = 1), lining the temporal horn of the lateral ventricle; (b) focal neocortical dysgenesis (n = 6), which consisted of cortical thickening, poor gray/white matter demarcation, abnormal gyration (n = 5), or limited schizencephaly (n = 1); (c) hippocampal malformations (n = 5), which presented as abnormal hippocampal formation associated with a cyst (n = 2), isolated malformation of the subiculum (n = 1), or bilateral hippocampal malformation (n = 2) consisting of an abnormal shape and a misplaced fimbria; (d) complex malformations of the temporal lobe, combining categories a, b, and c (n = 4). The age at onset, severity of the disease, and occurrence of generalized tonicoclonic seizures were not significantly different between patients with malformations and the entire population of patients with temporal lobe epilepsy. CONCLUSION: MR analysis of temporal lobe malformations allowed a precise determination of the extent of the malformations and the presence or absence of associated hippocampal disease, all of which are of great help in the preoperative evaluation of patients with intractable epilepsy.

Adolescent↗
PubMed1995

Hippocampal MRI volumetrics and temporal lobe substrates in medial temporal lobe epilepsy.

Forty-nine consecutive patients undergoing anteromedial temporal lobe resection for medically intractable temporal lobe seizures, and averaging 2 yr (range 6 mo to 4 yr) postoperative follow-up, were selected for a retrospective study. This study correlated magnetic resonance imaging (MRI) derived hippocampal volumetrics, preoperative demographics, postoperative seizure control, and tissue analysis, including hippocampal CA (cornu ammonis) field neuronal, and glial cell counts, and immunohistochemistry (IHC) evidence for dentate sprouting and reorganization. These measures were compared in hippocampi with or without an adjacent presumptive epileptogenic temporal lobe mass. Mesial temporal sclerosis (MTS) was defined as > 50% neuronal cell loss averaged across all CA fields with NPY (neuropeptide-y) and somatostatin reorganization. These patients may or may not include granule cell sprouting as determined by dynorphin staining. Patients were divided into two groups based on CA field neuronal cell counts, one averaging > 50% cell loss and one averaging < 50% cell loss. For the MTS group (N = 38), 89% had significant volumetric atrophy of the ipsilateral hippocampus, 74% had dentate reorganization, and complete seizure control was seen in 76% of these patients. In one subgroup of the < 50% cell loss group, patients with medial temporal lobe epilepsy caused by a mass in the medial temporal lobe (mass group) (N = 6), 33% demonstrated significant volumetric atrophy of the hippocampus ipsilateral to the mass, 0% had dentate sprouting, and seizures were completely controlled in 67%. For the second subgroup of the < 50% cell loss group, patients without mass lesions (N = 5) who were classified as the paradoxical medial temporal lobe epilepsy group (paradoxical group), 20% had ipsilateral hippocampal atrophy, 0% had dentate reorganization, and complete seizure control was seen in 60% of these patients. In conclusion, for the MTS group, hippocampal atrophy proven by MRI volumetrics was highly predictive of significant neuronal cell loss and an excellent indicator of success. However, in patients who had a foreign mass, hippocampal atrophy was not necessarily indicative of significant neuronal cell loss and MRI volumetrics was not a factor in the determination of a successful outcome. Furthermore, patients without mass lesions who have normal volumetrics but demonstrate hippocampal disease through invasive electrode monitoring, are likely to have paradoxical medial temporal lobe epilepsy, seizures beginning at a later age, and a lower, but not insignificant, success rate than the classical mesial temporal sclerosis group.

Adolescent↗
PubMed1978

[The inscisural porencephaly of the temporal lobe and the "temporal lobe agenesis syndrome" (author's transl)].

Clinical, radiological and pathomorphological investigations on five cases offering the patterns of the so-called temporal lobe agenesis syndrome (Robinson) have shown that this is not always originally malformative, but may be due to vascular processes in the sense of porencephalic defects, with all their pathomorphological features. We think that compression of the vein of Rosenthal by inscisural hippocampal herniation is the most probable aetiological mechanism. Earle, Baldwin and Penfield also described large temporal defects in connexion with their impressive demonstration of the inscisural herniation of the hippocampal gyrus at birth. We propose to use the name of--inscisural porencephaly--for this state.

Adolescent↗
PubMed1999

Temporal lobe epilepsy, temporal lobectomy, and major depression.

Sixty-two patients with medically intractable complex partial seizures who had either surgical or no surgical intervention were followed up at a mean of 10.9 years after surgery or initial evaluation. Of the 49 surgical patients, 45% had a life-time history of depression, versus 15% of the 13 patients in the nonsurgical comparison group. In the surgical group, 77% had prior history of depression; of these, 47% experienced no further episodes after surgery. Depression occurred de novo after lobectomy in 5 surgical patients (approximately 10%), 4 developing depression within 1 year. Presurgical presence of depressive episodes predicted continued postoperative depressive episodes. The significantly higher depression rate in patients with temporal lobe seizure foci suggests limbic system dysfunction in the increased risk for depression. Postsurgical resolution of episodes in almost 50% of these patients supports the tenet that depression per se is not a contraindication for surgery in patients with intractable seizures.

Adult↗
PubMed2002

Mesial temporal lobe epilepsy with lateral temporal lobe abnormalities in magnetoencephalography and glucose metabolism.

Magnetoencephalography (MEG) and positron emission tomography (PET) revealed abnormal findings in the lateral temporal lobe of a 22 year old female with mesial temporal lobe epilepsy. Electroencephalography identified the epileptogenic focus in the left mesial temporal lobe and standard anterior temporal lobectomy resulted in a good surgical outcome. These discrepancies can be explained by the presence of anatomical and functional pathways between the mesial and lateral temporal structures, or pathophysiological abnormalities in both the mesial and lateral temporal lobes. Careful evaluation is necessary for analysis of MEG and PET findings in patients with temporal lobe epilepsy.

Adult↗
PubMed1997

Intra-individual differences between technetium-99m-HMPAO and technetium-99m-ECD in the normal medial temporal lobe.

UNLABELLED: Regional distributions of 99mTc-hexamethyl propyleneamine oxime (99mTc-HMPAO) and 99mTc-ethyl cysteinate dimer (99mTc-ECD) were compared in the normal brain. METHODS: Six paid, healthy volunteers (mean age 26 yr) had high-resolution neuroperfusion SPECT using both 99mTc-HMPAO and 99mTc-ECD on separate days. RESULTS: Regional distribution of the two tracers differed. Technetium-99m-HMPAO accumulated more in the thalamus, frontal lobe, temporal lobe and cerebellum than 99mTc-ECD, which accumulated more in the occipital and parietal lobes. There was a considerable difference in the accumulation of the two tracers in the medial temporal lobe. The percent accumulations of 99mTc-HMPAO and 99mTc-ECD in the medial temporal lobe compared with the mean global cerebral cortical accumulation were 93.9% +/- 2.4% and 83.1% +/- 4.1% (mean +/- s.d.), respectively. CONCLUSION: The results suggest that 99mTc-HMPAO and 99mTc-ECD require specific and separate criteria for diagnosing temporal lobe pathologies, such as dementia and temporal lobe epilepsy.

Adult↗