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PubMed2004

Memory relationships between MRI volumes and resting PET metabolism of medial temporal lobe structures.

Prior studies of temporal lobe epilepsy (TLE) patients showed that MRI volumes and resting PET scan measures of temporal lobe structures were related to memory. Weintrob and colleagues [Ann. Neurol. 2002;51:442-7] reported that PET glucose uptake in the left perirhinal cortex predicted verbal paired associate (PA) learning, whereas MRI volume of the left hippocampus did not. We investigated whether MRI volumes could account for memory functioning if both PET and volumes were from the same region in 18 TLE patients. Volumes and glucose uptake of the hippocampus and parahippocampal gyrus (PHG) were compared with WMS-III performance. Significant correlations were observed between hippocampal volumes and PA and Logical Memory (LM) Percent Retention, but not between memory and PHG volumes or any PET measures. Multiple regression revealed that hippocampal volumes, but not PHG volumes or PET, significantly predicted PA and LM retention scores. These findings suggest that hippocampal volumes provide unique information regarding memory.

Adolescent↗

PubMed2001

Interictal 99mTc-HMPAO SPECT in temporal lobe epilepsy: relation to clinical variables.

PURPOSE: Factors affecting blood flow observed by interictal single-photon emission computed tomography (SPECT) images in temporal lobe epilepsy (TLE) have not been systematically studied or consistently demonstrated. We evaluated interictal SPECT results with respect to many clinical variables in a large population of TLE patients, all of whom underwent temporal lobectomy. METHODS: Interictal 99mTc-HMPAO SPECT scans from 61 TLE patients were obtained before an anterior temporal lobectomy. SPECT was analyzed using a region of interest analysis (ROI) in the cerebellum, anterior temporal lobe, lateral temporal lobe, mesial temporal lobe, whole temporal lobe, and inferior frontal lobe. Asymmetry indices (AIs) were calculated. Correlative analysis of AIs and clinical variables was performed. RESULTS: The AIs from TLE patients differed significantly from those of controls in the anterior temporal (p < 0.01), lateral temporal (p < 0.001), and whole temporal (p < 0.01) regions. No consistent overall correlation between the AIs and clinical variables existed. In right TLE (RTLE) only, AIs in the lateral and whole temporal lobe were positively correlated with age of onset (r = 0.470, p < 0.05; r = 0.548, p < 0.01, respectively). Similarly, in RTLE only, duration of epilepsy was negatively correlated with the anterior (r = -0.395, p < 0.05) and mesial (r = -0.45, p < 0.05) temporal lobe AI. No correlations were found between clinical variables and AIs in left TLE (LTLE) patients. CONCLUSIONS: Significant correlation of age at onset and duration of epilepsy with AIs in RTLE but not LTLE suggests physiologic processes may be determined in part by laterality of TLE. Clinical applications are problematic.

Adult↗

PubMed2001

Differential neuropsychological patterns of frontal- and temporal-lobe dysfunction in patients with schizophrenia.

The frontal and temporal lobes have been implicated as pathogenic sites for schizophrenia, although there is a marked heterogeneity of brain function and structure between individual patients. It is currently unclear whether some patients with schizophrenia exhibit primarily frontal lobe dysfunction, while others exhibit primarily temporal-lobe dysfunction. The current investigation examined this issue in a preliminary way by using neurocognitive tests to discriminate test performances of patients with schizophrenia from patients without schizophrenia who had definitive neurological evidence of either frontal- or temporal-lobe dysfunction. Of the patients with schizophrenia, 20.7% were classified as having a frontal lobe dysfunction profile, while 19.3% had a temporal lobe dysfunction profile. Results further clarify neurobiological heterogeneity in schizophrenia by demonstrating that a substantial number of patients with schizophrenia exhibit either primarily frontal- or temporal-lobe dysfunction. Results may partially explain the inadequacy of neurobiological models for schizophrenia that do not consider these differential patterns of dysfunction.

Adult↗

PubMed1993

The neuropathology of temporal lobe epilepsy.

Complex partial epilepsy arising in the temporal lobe has been associated with several types of pathologic lesions including Ammon's horn sclerosis, malformations, neoplasms, and inflammatory scars from infarcts or infection. These lesions are usually situated at various sites in the medial temporal lobe, so that one of the enigmas of attempting to understand the pathogenesis of TLE pertains to the clinical manifestation of a single epileptic disorder which is associated with dissimilar lesions at dissimilar sites. Recent demonstrations of an alteration in temporal lobe anatomy, i.e. malformations of the normal circuitry of the temporal lobe and foci of microdysgenesis, have given rise to the hypothesis that insults which occur during a critical period of brain development could alter the connections within the hippocampus and predispose it to increased excitability and seizurogenesis. Such a hypothesis forces us to reconsider TLE in reference to risk factors which may act as "teratogens" and produce these malformations. These malformations may range from a subtle alteration in the neurotransmitters of the dentate gyrus to large areas of cortical dysplasia or the hamartomatous neoplasms seen in TLE. A reevaluation of the neuroanatomical disruptions created by the various lesions may allow us to define a minimal optimal surgical resection for each lesion; or, the definitions of neurotransmitter deficits may lead to alternative pharmacologic therapies. As neuropathologists we have the exciting opportunity to participate in the definition of the neuropathology of temporal lobe epilepsy.

Animals↗

PubMed2004

Cerebral autoregulation improves in epilepsy patients after temporal lobe surgery.

Patients with temporal lobe epilepsy (TLE) often show increased cardiovascular sympathetic modulation during the interictal period, that decreases after epilepsy surgery. In this study, we evaluated whether temporal lobectomy changes autonomic modulation of cerebral blood flow velocity (CBFV) and cerebral autoregulation. We studied 16 TLE patients 3-4 months before and after surgery. We monitored heart rate (HR), blood pressure (BP), respiration, transcutaneous oxygen saturation (sat-O(2)), end-expiratory carbon dioxide partial pressure (pCO(2)) and middle cerebral artery CBFV. Spectral analysis was used to determine sympathetic and parasympathetic modulation of HR, BP and CBFV as powers of signal oscillations in the low frequency (LF) ranges from 0.04-0.15Hz (LF-power) and in the high frequency ranges from (HF) 0.15-0.5Hz (HF-power). LF-transfer function gain and phase shift between BP and CBFV were calculated as parameters of cerebral autoregulation. After surgery, HR, BP(mean), CBFV(mean), respiration, sat-O(2), pCO(2) and HF powers remained unchanged. LF-powers of HR, BP, CBFV and LF-transfer function gain had decreased while the phase angle had increased (p<0.05). The reduction of LF powers and LF-gain and the higher phase angle showed reduced sympathetic modulation and improved cerebral autoregulation. The enhanced cerebrovascular stability after surgery may improve autonomic balance in epilepsy patients.

Adult↗

PubMed2005

Temporal lobe epilepsy in children: overview of clinical semiology.

Temporal lobe epilepsy in children has been less well studied compared to that seen in adults. Whereas hippocampal sclerosis is the most common etiology for the adult temporal lobe epilepsy syndromes, tumors and malformations of cortical development are more commonly seen in children. Differences in seizure semiology are also apparent. Temporal lobe epilepsy in very young infants may exhibit prominent motor manifestations reminiscent of extra-temporal seizures. These motor manifestations however decrease with increasing age and are less abundant in adults. Automatisms, which are commonly seen in temporal lobe epilepsy in all age groups, are simple at a younger age and become increasingly more complex and discrete with age. Several case studies, illustrated on the video are included in this review. They highlight the differences in temporal lobe seizure semiology between children and adults. [Published with video sequences].

Adolescent↗

PubMed2000

Neuronal dysfunction in children with newly diagnosed temporal lobe epilepsy.

We sought to determine whether neuronal dysfunction throughout the temporal lobes of children with temporal lobe epilepsy (TLE) is already as severe at the time of diagnosis as it is in patients with long-standing intractable TLE (INT-TLE). Proton magnetic resonance spectroscopic imaging was used to measure N-acetylaspartate/creatine (NAA/Cr) ratios in the temporal lobes of five consecutive children with newly diagnosed TLE (ND-TLE), five with INT-TLE, and 30 normal control subjects. The median age of those with ND-TLE and those with INT-TLE did not significantly differ (P = 0.92). All five patients with ND-TLE had bilateral reductions in the NAA/Cr ratio. Two of the five patients with INT-TLE had bilateral reductions in the NAA/Cr ratio; three had unilateral reductions in the NAA/Cr ratio. In the three patients with lesions the NAA/Cr ratio decrease extended outside these lesions. No significant differences were detected in any temporal lobe region between the ND-TLE and INT-TLE groups. The severity of the neuronal dysfunction in the children with ND-TLE was at least as severe as in those with INT-TLE and was not restricted to one temporal lobe, implying that the neuronal abnormalities observed in patients with TLE occur before the clinical manifestations.

Adolescent↗

PubMed2001

Impact of depressed mood on neuropsychological status in temporal lobe epilepsy.

OBJECTIVES: Depression is a common psychiatric complication of temporal lobe epilepsy. This study examined the effect of depressed mood on neuropsychological performance among patients with chronic temporal lobe epilepsy. METHODS: Seventy consecutive surgery candidates for medication resistant complex partial seizures of unilateral temporal lobe origin were assessed for psychiatric symptoms and underwent comprehensive neuropsychological assessment. RESULTS: Standardised psychiatric interview disclosed that 34% of the patient sample exhibited significant depression. Controlling for seizure frequency, patients with comorbid depression at the time of neuropsychological assessment exhibited significantly poorer performance on measures of intelligence, language, visuoperceptual ability, memory, and executive function. Within lateralised temporal lobe epilepsy groups, the adverse effects of depression on cognitive function were greater in patients with left temporal lobe compared with those with right temporal lobe epilepsy. In addition, depression seemed to be underrecognised and undertreated as none of the patients with epilepsy and comorbid depression were treated for their psychiatric condition at the time of admission for monitoring. CONCLUSIONS: Depression, a common psychiatric comorbidity among patients with chronic temporal lobe epilepsy, seems to be undertreated and to have adverse effects on cognitive functioning.

Adult↗

PubMed1993

Hippocampal sclerosis in children with intractable temporal lobe epilepsy: detection with MR imaging.

OBJECTIVE: Hippocampal sclerosis is the most common lesion associated with temporal lobe epilepsy. Temporal lobectomy is effective for the control of medically refractory seizures in these patients. Before the advent of MR imaging, hippocampal sclerosis was rarely diagnosed preoperatively. The purpose of this study was to determine the frequency of hippocampal sclerosis in children with intractable temporal lobe epilepsy and the accuracy and reliability with which hippocampal sclerosis can be diagnosed on the basis of MR findings in children. MATERIALS AND METHODS: We reviewed the MR images of 53 children (mean age, 10 years) with medically refractory temporal lobe epilepsy. The MR images were reviewed blindly and independently by two radiologists on two occasions, and were classified as showing hippocampal sclerosis, other lesions, or no abnormality. Hippocampal sclerosis was diagnosed when evidence of hippocampal atrophy was present or hippocampal signal intensity was abnormal without evidence of a mass lesion. RESULTS: MR images showed hippocampal sclerosis in 30 children (57%), other lesions in 10 (19%) (tumors in eight, cavernous angioma in one, and ectopic gray matter in one), and no abnormality in 13 (24%) (intraobserver agreement: kappa = 0.77 and 0.84, interobserver agreement: kappa = 0.76). MR lateralization was concordant with ictal EEG in 36 (92%) of 39 children. Hippocampal sclerosis was bilateral in one child and associated with extrahippocampal lesions in nine. Hippocampal sclerosis was detected on MR images of 11 (85%) of 13 children with pathologic confirmation of hippocampal sclerosis. Beneficial results were seen in 26 (90%) of 29 children who had temporal lobectomy. CONCLUSION: Hippocampal sclerosis is the most common lesion in children with intractable temporal lobe epilepsy, and it can be detected reliably and accurately on MR images. We suspect that hippocampal sclerosis is underdiagnosed in children, possibly leading to postponement of surgery in children with refractory seizures.

Adolescent↗

PubMed1993

Subtemporal amygdalohippocampectomy for treating medically intractable temporal lobe epilepsy.

A SUBTEMPORAL AMYGDALOHIPPOCAMPECTOMY technique has been developed for mesial temporal lobe epilepsy. The conventional subtemporal approach has been modified to diminish temporal lobe retraction and the risk of damage to the temporal lobe. In the new technique, the surgeons' position has moved from above to below and the approach has been changed from anterolateral to posterolateral, thereby avoiding the voluminous and steeply inclined anterior temporal lobe. By this modified approach, it was unnecessary to remove the roof of the external auditory meatus and it was estimated that both the retraction pressure and the extent of temporal lobe retraction were reduced. To date, surgeons using this approach have operated on four patients with temporal lobe epilepsy whose epileptic foci were in the mesial temporal structure; the inferior temporal gyrus, the temporal tip, the vein of Labbé, and the ventral bridging veins were preserved. After surgery, two patients became completely free of seizures and the other two showed over 90% reduction in seizure frequency without neurological sequelae. Postoperative visual field examination revealed full visual fields without quadrantanopsia. This approach can preserve the temporal stem and lateral temporal lobe, it can be used to remove as much of the posterior hippocampus as necessary, and it can be extended to conventional lobectomy if it is indicated.

Adult↗

PubMed1996

Age at illness onset and left temporal lobe length in males with schizophrenia.

Post-mortem data suggest that in schizophrenia, temporal lobe length may be associated with age at illness onset. We used sagittal magnetic resonance images standardly acquired in reference to a coronal pilot image to obtain linear measurements of the left hemisphere in 38 male schizophrenic patients early in the course of their illness and 21 matched normal controls. In addition to temporal lobe and anterior temporal lobe (anterior to the anterior commissure) lengths, measurements of maximal brain and skull lengths were also obtained. The data show that differences in temporal lobe length between patients and normal controls are primarily due to significant differences between the groups in the global measures of brain and skull lengths. However, within the patient group, a significant association between temporal lobe length and age at onset of psychosis was observed. The same association was observed when the anterior part of the temporal lobe was measured separately. These associations remained significant after controlling for multiple variables such as subject height and brain and skull lengths. Further statistical evaluations showed that the temporal lobe was significantly shorter among the subgroup of schizophrenics whose illness began before the age of 23. The data suggest that temporal lobe length may be a useful variable for investigating the biological heterogeneity of schizophrenia and highlight important technical issues regarding current efforts to measure the volumes of temporal lobe structures.

Adult↗

PubMed1982

Psychological status related to surgical control of temporal lobe seizures.

Patients who underwent temporal lobe surgery with diagnosis aided by stereoelectroencephalography (SEEG) were evaluated psychosocially before surgery and at one month and one year after surgery. Patients who were not operated on but who also had been evaluated by SEEG served as controls. These patients were evaluated at time periods comparable to those of the operated cases. At one year after surgery, patients whose seizures had been relieved had improved in Degree of Dependency, Work Performance, and Non-Family Relationships. Patients whose seizures were not controlled by surgery and nonoperated patients did not show any significant change in psychosocial measurements one year postoperatively. Psychosocial improvements were seen regardless of the side of the brain operated. While patients whose seizure were reduced experienced memory deficits of the type associated with side of the temporal lobe resection, the data suggested that there was improvement in intellectual score and, in the case of right-sided surgery patients, memory functions associated with the contralateral, intact hemisphere.

Adolescent↗

PubMed2004

[Place of surgery in the treatment of adult temporal lobe epilepsy].

Surgery for temporal lobe epilepsy has made significant progress during the past twenty years: in addition to traditional factors (frequency of partial seizures and relative resistance to medical treatment), the possibilities offered by MRI in a large number of cases to detect the responsible lesion (hippocampal sclerosis in the majority of cases) has led to an increase in the use of surgical methods. Furthermore, other examinations (EEG-video, SPECT Depth-electrode recording) now permit precise localization of the epileptic focus. Surgical techniques have likewise been considerably modified: in parallel to classical temporal lobectomy, new surgical methods offer more restricted resection of the lateral cortex. The results are, on the whole, quite satisfactory, as three-quarters of patients can be considered cured or greatly improved. The length of post-operative follow-up does not seem to influence the quality of the results, as observed by the end of the second year.

Electroencephalography↗

PubMedDate not supplied

Temporal lobe epilepsy caused by choroid plexus papilloma in the temporal horn.

Choroid plexus papilloma (CPP) arising in the temporal horn is rare in adult population, and to the best of our knowledge, there has been no report of such a case with temporal lobe epilepsy (TLE). The authors describe a unique case of a 27-year-old woman who was diagnosed as TLE and was found to have a CPP in the temporal horn. Choroid plexus papilloma of the temporal horn, even though rare, can be found in adult population and be causally related to temporal lobe epilepsy.

Adult↗

PubMed1997

"Cavernous sinus EEG": a new method for the preoperative evaluation of temporal lobe epilepsy.

PURPOSE: In presurgical evaluation of temporal lobe epilepsy (TLE), invasive methods are necessary if results of various noninvasive methods are not sufficiently convergent enough to identify the epileptogenic area accurately. To detect the epileptiform discharges originating specifically from the mesial temporal lobe, we applied the cavernous sinus catheterization technique. METHODS: We placed Seeker Lite-10 guide wire electrodes into bilateral cavernous sinus through the internal jugular veins to record EEG (cavernous sinus EEG) in 6 patients with intractable TLE. Scalp EEG was simultaneously recorded in all 6 and electrocorticogram (ECoG) was also recorded in 4. RESULTS: The cavernous sinus EEG demonstrated clear epileptiform discharges, sometimes even when they were absent on the simultaneously recorded scalp EEG. The epileptiform discharges recorded from the cavernous sinus electrodes were specifically associated with those in the mesial temporal region on ECoG. Ictal EEG pattern originating from mesial temporal lobe was also clearly documented on the cavernous sinus EEG. CONCLUSIONS: This new, semi-invasive method of identifying epileptogenic areas can detect the epileptiform discharges specifically arising from the mesial temporal lobe; it is as useful as or complements the invasive techniques such as foramen ovale or depth recording.

Adolescent↗

PubMed1991

Developmental anterobasal temporal encephalocele and temporal lobe epilepsy.

The authors describe the association between an antero-basal temporal lobe encephalocele and medically intractable temporal lobe epilepsy in three patients treated successfully by surgery. Two men and one woman, aged 26 to 37 years (mean 31 years), had onset of complex automatism and generalized seizures in their second and fourth decades (mean age 22.7 years). They had been epileptic for 6 to 14 years (mean 8.3 years) before surgery. Preoperative electroencephalograms localized ictal epileptic activity to the left mesial temporal lobe in all cases, and neuropsychological testing revealed dominant temporal lobe dysfunction. Magnetic resonance (MR) imaging demonstrated an anteromedial basal temporal encephalocele extending into the pterygopalatine fossa through a bone defect at the base of the greater sphenoid wing in the region of the foramen rotundum and pterygoid process, a discrete center of embryonal chondrification. At surgery, the encephaloceles were found in front of the uncus, and an area of gliosis extended from the encephalocele to the amygdalohippocampal region. All patients have been seizure-free following anterior temporal resection and amygdalohippocampectomy including the encephalocele. These three cases delineate a condition of disordered embryogenesis wherein a developmental anterobasal temporal encephalocele acts as the substrate for temporal lobe epilepsy. This lesion may be diagnosed preoperatively with MR imaging and should be considered in the differential diagnosis of late-onset temporal lobe epilepsy.

Adult↗

PubMed2000

Temporal lobe epilepsy: when are invasive recordings needed?

Temporal lobe epilepsy (TLE) is the most common type of medically intractable partial epilepsy amenable to surgery. In the majority of cases, the underlying pathology in temporal lobe epilepsy is mesial temporal sclerosis (MTS). Whereas historically invasive recordings were required for most epilepsy surgeries, indications have dramatically changed since the introduction of high-resolution MRI, which uncovers structural lesions in a high percentage of cases. No invasive recordings are required to perform a temporal lobectomy in patients with intractable epilepsy who have structural imaging suggesting unilateral MTS and concordant interictal and ictal surface EEG recordings, functional imaging, and clinical findings. Invasive testing is needed if there is evidence of bitemporal MTS on structural imaging and/or electrophysiologically, and additional information from functional imaging, neuropsychology, and the intracarotid amobarbital (Wada) test also does not help to lateralize the epileptogenic zone. Depth electrodes can be particularly helpful in this setting. However, no surgery is indicated, even without invasive recordings, if bitemporal-independent seizures are recorded by surface EEG and all additional testing is inconclusive. Other etiologies of TLE such as a tumor, vascular malformation, encephalomalacia, or congenital developmental abnormality account for about 30% of all patients who undergo epilepsy surgery. Epilepsy surgery is indicated after limited electrophysiologic investigations if neuroimaging and electrophysiology converge. However, approaches for resection in lesional temporal lobe epilepsy vary among centers. Completeness of resection is crucial and invasive recordings may be needed to guide the resection by mapping eloquent cortex and/or to determine the extent of the non-MRI-visible epileptogenic area. Specific approaches for the different pathologies are discussed because there is evidence that the relationship between the lesions visible on MRI and the epileptogenic zone varies among lesions of different pathologies, and therefore variable surgical strategies must be applied.

Adolescent↗

PubMed1990

Fields of origin and pathways of the interhemispheric commissures in the temporal lobe of macaques.

The interhemispheric connections of the cortical areas of the temporal lobe and some neighboring regions were investigated in monkeys (Macaca mulatta and Macaca fascicularis) by anterograde autoradiographic tracing, following injection of radioactively labeled amino acids. The results revealed that the interhemispheric projections of the temporal lobe course through three interhemispheric commissures on their way to the opposite hemisphere. The anterior commissure receives fibers from virtually the entire temporal lobe, including the temporal pole, superior and inferior temporal gyri, and parahippocampal gyrus. Moreover, area 13 of the orbitofrontal cortex, the frontal and temporal subdivisions of the prepiriform cortex, and the cortical and deep nuclei of the amygdala also contribute fibers to the anterior commissure. The heaviest projections arise in the rostral third of the temporal isocortex. These projections become progressively lighter from more caudal regions. By contrast, the corpus callosum receives fibers from the caudal two-thirds of the temporal lobe, including the temporal pole, superior and inferior temporal gyri, and parahippocampal gyrus. The heaviest projections arise in the caudal third of the temporal lobe and cross primarily in the caudal third of the corpus callosum, including the splenium. Progressively lighter projections arise more rostrally. Fibers from proisocortical and isocortical areas of the posterior parahippocampal gyrus cross in the ventralmost part of the splenium (inferior forceps), whereas cortical areas lateral to the occipitotemporal sulcus give rise to fibers that cross in the caudal part of the body of the corpus callosum and dorsal splenium. The dorsal hippocampal commissure receives fibers exclusively from the parahippocampal gyrus. The fibers of the corpus callosum, hippocampal commissure, and, to a lesser extent, the anterior commissure are intimately associated with the ventricular system as they course through the white matter of the temporal lobe. The fields of origin of the anterior commissure and corpus callosum overlap extensively over the caudal two-thirds of the temporal lobe. The posterior parahippocampal gyrus is unique in that it gives rise to fibers that cross in all three commissures.

Amygdala↗