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PubMed2004

A dissociation between implicit and explicit verbal memory in left temporal lobe epilepsy.

PURPOSE: Temporal lobe epilepsy patients are well known to present deficits on explicit verbal memory procedures (e.g., recall, recognition). The integrity of implicit memory procedures in these patients is not established. Previous studies in this area used implicit memory measures contaminated by the effects of explicit memory. METHODS: We examined the integrity of verbal implicit and explicit memory in left temporal lobe epilepsy (LTLE) patients and hypothesized that a clear dissociation in performance would be found with a relative preservation of implicit memory. TLE patients (n = 15) and age- and education-matched healthy normal patients (n = 15) were shown a 40-word study list, followed by a test phase requiring completion of word stems based on the study words or new/unseen words. Experimental conditions involved instructions to provide either the old (study) words or novel/nonlist words when completing the stem. Measures of automaticity and recollection provided uncontaminated indices of implicit and explicit memory, respectively. RESULTS: The data showed a significant difference (p < 0.001) between the patients (Recollection, 0.12; SD, 0.18) and controls (0.50, SD, 0.15) on the measure of explicit memory. In contrast, the patients (Automaticity, 0.51; SD, 0.11) and controls (0.45, SD, 0.18) performed similarly on the implicit memory measure, with patient scores clearly at normative levels based on other Process Dissociation Procedure data. CONCLUSIONS: The data demonstrate the integrity of implicit memory in LTLE patients. Finding a dissociation between the two forms of verbal memory in LTLE patients provides evidence that they rely on different neuroanatomic systems.

Adolescent↗
PubMed1996

MRI-guided flumazenil- and FDG-PET in temporal lobe epilepsy.

In temporal lobe epilepsy (TLE) patients without lesions, major hippocampal sclerosis, or atrophy on magnetic resonance imaging (MRI), the localizing power of [11C]flumazenil (FMZ) and 2-[18F]fluoro-2-deoxy-D-glucose (FDG) was compared using high-resolution positron emission tomography (PET) studies and individually coregistered MRI scans. Following complete clinical, neuropsychological, and electrophysiological evaluation, benzodiazepine receptor density was assessed using the FMZ equilibrium method. Thirty minutes later, interictal FDG-PET was performed under resting conditions. PET images were matched to three-dimensionally coregistered, T1-weighted MRI. Each temporal lobe (TL) was divided into 12 volumes of interest. The regional FMZ data were normalized with respect to average cortical values. For each patient the right-left asymmetries of rCMRGlc and normalized FMZ data were calculated. In 7 to 10 patients, mesial TL structures showed reduced FMZ binding, with a decrease by at least 10% in the affected TL. Reductions of 10% or more of rCMRGlc usually were more widespread than FMZ reductions and often involved lateral temporal cortex. The regions of most pronounced disturbances are not necessarily identical in both methods. Three patients had a complex correspondence of lateralization with PET, neuropsychological, and EEG data. In 4 patients, lateralization was less clear from EEG or neuropsychological results but was still consistent with lateralization by PET. In 3 of 10 patients, however, major discrepancies were found. These data suggest that the combination of neuropsychological testing, EEG, and MRI-guided FMZ- and FDG-PET will help to select patients with clearly defined epileptogenic foci especially in mesial TLE. Even in cases without MRI lesions, TL epileptic foci can be lateralized with consistency across the methods; FMZ-PET shows the pathologic focus more circumscribed than FDG-PET.

Adult↗
PubMed1993

Histochemical marker of human catecholamine neurons in ganglion cells and processes of a temporal lobe ganglioglioma.

A temporal lobe ganglioglioma was surgically removed from an 8-year-old boy who had developed temporal lobe paroxysmal convulsions. The present study describes staining reactions of the ganglioglioma tissue with histochemical methods designed to demonstrate the protein bodies, which are markers of catecholamine neurons in humans. Brookes' procedure for basic proteins and rhodamine B for lipids showed identical staining of the following: (1) spherical inclusion bodies in the neoplastic neurons, (2) large eosinophilic globules in the dilated neuronal processes, and (3) the protein bodies in the neurons of human locus ceruleus and sympathetic ganglion. We conclude that the catecholamine neurons of the ganglioglioma possess the same marker of aminergic identity as normal catecholamine neurons in humans. Thus, this marker could be used as an additional diagnostic tool for the identification of this type of tumor.

Biomarkers, Tumor↗
PubMed1996

Temporal lobe epilepsy caused by mesial temporal sclerosis and temporal neocortical lesions. A clinical and electroencephalographic study of 46 pathologically proven cases.

This study aims to determine whether there are important clinico-electrical differences between patients with temporal lobe epilepsy (TLE) secondary to mesial temporal sclerosis (MTS) and those with TLE secondary to a discrete temporal neocortical lesion (NL). The case histories, interictal EEG, seizure semiology, ictal EEG and postoperative outcome of 46 pathologically proven patients (31 MTS and 15 NL) were compared. A history of febrile convulsions (FC) was more common in MTS patients (58% versus 26%, P < 0.05), as was a history of a significant cerebral event at < 4 years of age (22% versus 0%, P < 0.05). There were no statistically significant differences in the incidence or nature of auras. No statistically significant differences between the groups were found in the interictal-EEG. With ictal semiology dystonic posturing occurred more frequently in MTS patients (mean 52% versus 26%, P < 0.05). Facial grimacing/ twitching occurred earlier in the seizures of NL patients (median 19 s versus 35 s, P < 0.05). There was an increased frequency of fast rhythmic sharp waves (> 4 Hz) in the ictal-EEG of MTS patients (mean 81% versus 60%, P = 0.05). The patients with NL developed bilateral ictal EEG changes more often (mean 55% versus 26%, P < 0.05) and more rapidly (mean 23 s versus 74 s, P < 0.005). The onset of ictal EEG seizure activity was bilateral more often in patients with NL (20% versus 4%, P < 0.005). There were no significant differences between the two groups for any of the video-EEG features, in terms of whether or not the feature occurred at least once in an individual patients. There was a tendency for MTS patients to have a higher seizure-free postsurgical outcome (87% versus 60%, P = 0.057). However, all the NL patients who were not free of seizures had had an incomplete lesion resection. We conclude that there are a number of clinico-electrical differences between patients with mesial TLE (MTLE) and patients with neocortical TLE (NCTLE), but that none of these are sufficient to allow a distinction to be made in an individual patient.

Adolescent↗
PubMedDate not supplied

[Defects in the visual field in resective surgery for temporal lobe epilepsy].

INTRODUCTION: Temporal lobe resection is the most used procedure in epilepsy surgery. Visual field defects after resection are frequent. AIM. We try to detect the frequency and severity of visual field defect after anterior temporal lobectomy (ATL) and to study the functional consequences. PATIENTS AND METHODS: We studied 30 patients with refractory temporal lobe epilepsy (15 men, 12 51 years, m= 32.9), in which ATL was performed (11 right, 19 left). The neocortical and hippocampal resection was variable. Visual field was studied with computerized campimetry type Humphrey. Our survey was filled to study the campimetric consequence, seizures incidence, quality of life and surgery satisfaction. RESULTS: Some campimetric disturb was found in 27 patients (90 %), superior or minor homonimus quadantapnosia in 18 (60 %), major one 8 and homonimus hemianopsia in one. Incongruent defects appeared in 19. The bigger neocortical and hippocampal resection was, the bigger defect, with exceptions. Only patient with a hemianopsia was conscious the deficit. 20 patients (66.6 %) were seizures free in the last year. 28 had better quality of life and 29 (96.6 %) would have chosen surgery again. CONCLUSION: Visual field defects after ATL, although frequent, have little functional consequences and in quality of life. The quality of life is better when seizures stopped. After ATL patients are very glad with their decision.

Adolescent↗
PubMed2004

The medial temporal lobe.

The medial temporal lobe includes a system of anatomically related structures that are essential for declarative memory (conscious memory for facts and events). The system consists of the hippocampal region (CA fields, dentate gyrus, and subicular complex) and the adjacent perirhinal, entorhinal, and parahippocampal cortices. Here, we review findings from humans, monkeys, and rodents that illuminate the function of these structures. Our analysis draws on studies of human memory impairment and animal models of memory impairment, as well as neurophysiological and neuroimaging data, to show that this system (a) is principally concerned with memory, (b) operates with neocortex to establish and maintain long-term memory, and (c) ultimately, through a process of consolidation, becomes independent of long-term memory, though questions remain about the role of perirhinal and parahippocampal cortices in this process and about spatial memory in rodents. Data from neurophysiology, neuroimaging, and neuroanatomy point to a division of labor within the medial temporal lobe. However, the available data do not support simple dichotomies between the functions of the hippocampus and the adjacent medial temporal cortex, such as associative versus nonassociative memory, episodic versus semantic memory, and recollection versus familiarity.

Animals↗
PubMed1982

Neuroendocrine dysfunction in temporal lobe epilepsy.

Since medial temporal lobe structures are involved in the modulation of endocrine function and temporal lobe epileptics commonly show personality changes that resemble endocrine disorders, the existence of neuroendocrine dysfunction in temporal lobe epileptics was investigated by comparing the response of serum luteinizing hormone levels with intravenous luteinizing hormone-releasing hormone infusion in patients and normal controls. Five of seven consecutive patients had response curves that fell almost entirely outside of the normal control range, and all seven had either baseline or peak values that were outside of the normal range. These findings suggest that hypothalamic-pituitary control of gonadotropin secretion may be altered among patients with temporal lobe epilepsy.

Adult↗
PubMed1999

An angiographically occult arteriovenous malformation in the medial parietal lobe presenting as seizures of medial temporal lobe origin.

We present an unusual case of a patient who was diagnosed with temporal lobe epilepsy and whose seizures were reduced markedly after excision of an angiographically occult arteriovenous malformation (AVM) located in the left medial parietal lobe. A 38-year-old man had complex partial seizures characterized by motionless staring with oroalimentary and behavioral automatisms since the age of 15 years. Magnetic resonance imaging (MRI) demonstrated a small lesion extending from the left posterior cingulate gyrus to the precuneus. There was no MRI evidence of mesial temporal sclerosis. Intracranial EEG recordings showed ictal onset from the left medial parietal lobe propagating to the medial temporal lobes. Clinical signs appeared when these discharges reached the temporal lobes. After excision of the lesion (which was histologically confirmed as an AVM), together with the marginal cortex, seizures were reduced significantly. Careful diagnostic evaluation of lesions such as the this one may reveal an epileptogenic lesion (zone) far from the region where scalp ictal discharges seem to arise. In our case, we hypothesize that false localization was due to propagation of ictal discharges from the parietal focus through the limbic system.

Adult↗
PubMed2004

Abnormal behavior in children with temporal lobe epilepsy and ganglioglioma.

Temporal lobe epilepsy in childhood is characterized by great clinical, electroencephalographic, and etiological diversity. The prognosis after temporal lobe epilepsy surgery in childhood is usually good, with most patients achieving complete seizure control. However, in some children behavior deteriorates postoperatively. We report two girls (2 and 6 years of age) with refractory seizures due to temporal lobe ganglioglioma. They exhibited aggression and hyperactivity since the beginning of their epilepsy. In both patients, behavioral disturbances worsened postoperatively, despite complete seizure control. Patients and parents should be advised about possible behavioral disturbances after epilepsy surgery, especially in the presence of a temporal lobe developmental tumor, even when seizure control is achieved postoperatively.

Anticonvulsants↗
PubMed2000

Psychiatric aspects of temporal lobe epilepsy before and after anterior temporal lobectomy.

OBJECTIVES: Psychopathology has been reported to be prevalent both before and after surgical treatment for medically intractable temporal lobe epilepsy. Individual patients were evaluated prospectively to assess the effect of anterior temporal lobectomy (ATL) on prevalence and severity of psychiatric disease. METHODS: Psychiatric status was assessed in a consecutive series of epilepsy patients before and 6 months after ATL using a structured psychiatric interview, psychiatric rating scales, and self report mood measures. RESULTS: A DSM-III-R axis I diagnosis was present in 65% of patients before and after surgery. The most common diagnoses were depression, anxiety, and organic mood/personality disorders. There was a trend for major psychiatric diagnoses to be more common in patients with right compared to left temporal lobe seizure focus, both before and after surgery. The apparent stability in the overall rate of psychiatric dysfunction concealed onset of new psychiatric problems in 31% of patients in the months shortly after surgery, and resolution of psychiatric diagnoses in 15% of patients. In the group as a whole, the severity of psychiatric symptoms was lower at 6 months postsurgery than before temporal lobectomy. CONCLUSIONS: The overall prevalence of psychiatric dysfunction was comparably high before and after ATL, but individual changes in psychiatric status and changes in severity of symptoms occurred in many patients in the 6 months after surgery.

Adult↗
PubMed1997

Medial temporal lobe atrophy in memory disorders.

Medial temporal lobe atrophy determined by temporal lobe oriented computed tomography (CT), 1 year before death, is strongly associated with histopathologically confirmed Alzheimer's disease (AD). The aim of this study was to assess the diagnostic accuracy of medial temporal lobe measurement for the diagnosis of AD in patients referred to a memory disorders clinic, especially those at an early stage of the disease. CT oriented to the temporal lobe was performed in 333 subjects aged 41-93 years consecutively recruited in a Memory Disorders Clinic: 124 had probable AD, Mini Mental State score (MMS) = 17 (8); 50 possible AD [MMS = 21 (5)]; and 119 patients had miscellaneous memory disorders [MMS = 22 (7): frontotemporal lobe dementia, subcortical dementia, cortical Lewy body disease, vascular dementia, Korsakoff syndrome, focal atrophy, etc.]. There were also 19 anxious/depressed patients [MMS = 29 (1)] with normal performance on memory tests, and 21 controls. The minimum width of the medial temporal lobe was measured. The best cut-off to distinguish AD patients from non-AD patients was 11.5 mm, in agreement with data in the literature. At this threshold, 84% of probable AD patients had a positive test and 90% of controls and anxious/depressed patients had a negative test. For the diagnosis of probable AD, sensitivity of the measurement was 0.81, specificity 0.95, predictive positive value 0.99, predictive negative value 0.45, and diagnostic accuracy 0.83. The test was positive in half the possible AD patients, and half those with miscellaneous memory disorders. It was negative in all anxious/depressed patients. Therefore, temporal lobe oriented CT might be a valuable tool for assessment of medial temporal lobe atrophy in AD routine practice.

Adult↗
PubMed2006

Can intraoperative electrocorticography patterns predict surgical outcome in patients with temporal lobe epilepsy secondary to unilateral mesial temporal sclerosis?

INTRODUCTION: Intraoperative electrocorticography (ECoG) can be performed in cases of temporal lobe epilepsy due to hippocampal sclerosis (TLE-HS). However, its significance and correlation with surgical outcome are still controversial. OBJECTIVES: To analyze the electrophysiological characteristics of temporal lobe structures during ECoG of patients with TLE-HS, with emphasis on the comparison between pre- and post-resection recordings and surgical outcome. PATIENTS AND METHODS: Seventeen patients with refractory TLE-HS submitted to corticoamigdalohipocampectomy were included in the study. Clinical variables included age at the onset, duration of epilepsy and seizure outcome. The post-operative follow-up ranged from 24 to 36 months. According to outcome subjects were divided in two subgroups: (A) individuals free of seizures (Engel 1A), and (B) individuals not-free of seizures (Engel 1B-IV). Four patterns of ECoG findings were identified: isolated discharges; high frequency spikes (HFS); continuous discharges; combination of isolated discharges and HFS. According to predominant topography ECoG was classified as mediobasal, lateral (or neocortical), mediobasal and lateral. RESULTS: The progressive removal of the temporal pole and the hippocampus was associated with significant decrease of neocortical spikes. No correlation between clinical variables and seizure outcome was observed. Patients who only had isolated spikes on intraoperative ECoG presented a statistical trend for excellent surgical control. Patients who presented temporal pole blurring on MRI also had better post-surgical seizure outcome. CONCLUSIONS: This study showed that out of diverse clinical and laboratory variables, only isolated discharges on intraoperative ECoG and temporal pole blurring on MRI predicted excellent post-surgical seizure outcome. However, other studies with larger number of patients are still necessary to confirm these findings.

Adult↗
PubMed2003

[Qualitative and quantitative MRI findings in temporal lobe epilepsy].

PURPOSE: Mesial temporal sclerosis is the most common pathological finding in temporal lobe epilepsy (TLE). Accurate identification and localization of this pathology before surgery is obligatory for a good prognosis after the operation. In this study we compared the results of qualitative and quantitative MR findings of the hippocampus in TLE. MATERIALS AND METHODS: The study group consisted of 42 patients with the definitive diagnosis of temporal lobe complex partial seizure and 42 control subjects. Extrahippocampal lesions had been detected in 10 patients. Qualitative evaluation was performed by T2-weighted FSE, fast FLAIR, T1-weighted fast IR sequences on coronal plane. We also performed volumetric measurements of the hippocampus in 32 patients with TLE and compared the results with those of the control group. The mesial temporal lobes were investigated with SVS-proton MR spectroscopy using a PRESS sequence with an echo time of 135 milliseconds and T2 relaxation values. RESULTS: Hippocampal pathology was detected on paracoronal plane at T1-weighted fast IR (84%), T2-weighted FSE (60%) and fast FLAIR (88%) images. On comparing the hippocampal volumes of the patient and control groups, the hippocampal of the control group were found to be significantly larger (p < 0.05). Considering the right-left volume differences, 28 patients (88%) were found to have unilateral hippocampal atrophy. The most consistent MR spectroscopic parameter for definite lateralization was the NAA/Cho + Cr ratio (100%). Accurate epileptic focus lateralizations were made in 27 subjects (84%) by using hippocampal T2 relaxation time, and in 12 subjects (33%) by using temporal white matter T2 relaxation time. CONCLUSION: MR imaging is highly sensitive in detecting and locating abnormalities in the temporal lobe and hippocampus in patients with TLE. Implementation of FLAIR and T1 IR sequences in the routine MR examination of patients with TLE is recommended. With adequate asymmetry index, NAA/Cho + Cr ratio is sensitive in predicting the side of involvement in patients with TLE. For medically intractable TLE patients MRS is a very important guiding tool prior to surgery.

Adolescent↗
PubMed2003

Extratemporal quantitative MR volumetrics and neuropsychological status in temporal lobe epilepsy.

Neuropsychological studies of temporal lobe epilepsy have focused heavily on the nature and extent of memory dysfunction and its relationship to the neuropathological status of the hippocampus and related mesial temporal lobe structures. In this study, we examined whole brain and lobar quantitative MRI volumes and comprehensive neuropsychological performance in 58 patients with temporal lobe epilepsy and 62 healthy controls in order to determine (1) the nature and degree of extratemporal structural abnormalities in localization-related temporal lobe epilepsy: (2) the nature and degree of cognitive abnormalities outside of anterograde memory function; and (3) the relationship of volumetric abnormalities to neuropsychological status. Temporal lobe epilepsy patients exhibited significant reduction in the volume of adjusted (age, gender, height) total cerebral tissue (-5.8%), more evident in white (-9.8%) compared to gray matter (-3.0%) tissue volumes. Significant volumetric reductions were evident across frontal, temporal and parietal but not occipital lobe regions. Subarachnoid but not total ventricular CSF was significantly increased in epilepsy patients. Neuropsychological abnormality was generalized in nature, consistent with the generalized nature of the morphometric abnormalities, and reductions in cerebral tissue volumes were directly associated with poorer cognitive performance. In summary, patients with temporal lobe epilepsy exhibited clinically significant structural and functional abnormalities that extended outside the epileptogenic temporal lobe. The degree to which these structural and cognitive abnormalities are due to factors that cause the epilepsy, as opposed to reflecting the consequences of chronic epilepsy (e.g., duration and severity of epilepsy), remain to be determined.

Adolescent↗
PubMed2005

Progression in temporal lobe epilepsy: differential atrophy in mesial temporal structures.

OBJECTIVE: To determine the relationship between hippocampal, amygdalar, and entorhinal cortex atrophy and duration of epilepsy, presence of secondary generalized seizures, and prolonged childhood febrile convulsions in patients with pharmacologically intractable temporal lobe epilepsy (TLE). METHODS: Volumetric MRI of the hippocampus, amygdala, and entorhinal cortex were performed in 86 consecutive patients with TLE and 44 age- and sex-matched healthy control subjects. Linear regression analysis was used to explore the relation between the volumetric measurements and the clinical parameters. RESULTS: In simple regressions, duration of epilepsy but not age at seizure onset was related to hippocampal (r2 = 0.19, p < 0.001), entorhinal cortex (r2 = 0.11, p = 0.002), and amygdalar (r2 = 0.15, p < 0.001) atrophy ipsilateral to the seizure focus. Prediction of the regression function to time of onset of recurrent seizures (time = 0) resulted in a y intercept of < 0 for the hippocampus and the entorhinal cortex but was not different from 0 for the amygdala. Patients with a positive history of febrile convulsions had smaller hippocampal volumes ipsilateral to the seizure (p < 0.001). No relationship was found between febrile convulsions and entorhinal cortex and amygdalar volumes or between secondary generalization of seizures and any mesial temporal volume. CONCLUSION: Progressive volume loss in the mesial temporal lobe in relation to duration of epilepsy is not limited to the hippocampus but affects the entorhinal cortex and the amygdala.

Adolescent↗
PubMed1989

Temporal lobe syncope: clinical variants.

Temporal lobe syncope (TLS) is a term coined by Landolt. Characteristically, the patient has psychomotor and drop attacks, and the interictal electroencephalogram (EEG) shows temporal lobe epileptic abnormalities. TLS is synonymous with type III complex partial seizures (CPSs) in the Delgado Escueta classification. Several variants of TLS can be recognized including atonic akinetic, simple akinetic, atonic, atonic-tonic complex (automatisms), sexual seizures, stress-induced convulsions, and gelastic atonic seizures. TLS must be distinguished from drop attacks of vertebrobasilar insufficiency and associated EEG abnormalities, and from hereditary tachyarrhythmias mimicking stress-induced convulsions. Epileptic falls and drop attacks are discarded by ictal EEG recordings. Recognition of TLS variants is important in the prospective evaluation of the surgical treatment of epilepsy given the past conflicting reports on the differential outcome of surgically treated CPSs. TLS is an attractive clinical term, easy to remember, and with pathophysiologic relevance to the clinician confronting the patient with a history of syncope and whose EEG discloses temporal lobe paroxysmal activity. The detailed ictal electrophysiology of TLS is unknown.

Adult↗