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PubMed1996

Temporal lobe arteriovenous malformations: surgical management and outcome.

BACKGROUND: Temporal lobe arteriovenous malformations (AVMs) represent a subgroup of intracranial AVMs with particular characteristics and management issues. METHODS: We performed a retrospective analysis of 24 consecutive patients with temporal lobe AVMs treated with surgical excision. Factors such as location, size, arterial feeders, venous drainage, and clinical follow-up were recorded for each. Results were compared with those of 132 patients with nontemporal lobe AVMs surgically treated over the same time period. RESULTS: Sixteen of the temporal AVMs were located in the convexity, six in the mesotemporal region, and two were predominantly intraventricular. The mode of presentation was seizure in 11 patients, hemorrhage in 7, headache in 4, and 2 were asymptomatic. Patients with convexity AVMs more commonly presented with seizures, whereas patients with mesotemporal or intraventricular AVMs were more likely to present with hemorrhage. One patient with subarachnoid hemorrhage from a basilar artery aneurysm died. Postoperatively, 2 patients (8.3%) had a new hemiparesis and dysphasia, 1 (4%) had a new dysphasia and hemianopsia, and 3 others (13%) were left with an isolated superior quadrant field deficit. Lasting surgical morbidity other than isolated field deficit was 13% for patients with temporal AVMs and 15% for those with nontemporal AVMs. CONCLUSIONS: Temporal lobe AVMs may be successfully resected using a direct microsurgical approach with limited morbidity and excellent prognosis for recovery. Most of the deficits relating to AVM hemorrhage and those of the immediate postoperative period improved significantly over the subsequent few months.

Adolescent↗

PubMed1983

Ictal tachycardia during temporal lobe seizures.

A seldom-recognized accompaniment of temporal lobe seizures is tachycardia. This phenomenon was observed in 12 consecutive patients in whom spontaneous seizures were recorded with simultaneous electroencephalographic, electrocardiographic, and videotape monitoring; this finding indicates with a 99% confidence level that this phenomenon may occur in at least 64% of temporal lobe seizures. The autonomic influences responsible for ictal tachycardia during temporal lobe seizures may be inconsequential in patients without cardiac disease but can have serious consequences in patients with cardiac disease.

Aged↗

PubMed1997

Results of surgical treatment in temporal lobe epilepsy with chronic psychosis.

The combination of psychosis and refractory temporal lobe epilepsy is not rare. However, patients with chronic interictal psychosis and refractory epilepsy are rejected from many epilepsy surgery programmes purely on psychiatric grounds. It is often assumed that disturbed behaviour will prevent adequate preoperative evaluation or that the patients are unable to provide informed consent for preoperative investigations and for surgery. The observation that the psychosis usually does not improve after operation and fears of an exacerbation of psychosis with post-surgical seizure remission, analogous to 'forced normalization', are further deterrents to surgery in these patients. We describe five patients with the dual diagnoses of medically intractable temporal lobe epilepsy and chronic psychosis who underwent temporal lobe resection. The patients were able to provide informed consent and were easily managed during preoperative investigation. Seizure outcome has been excellent in all. Neither temporal lobe resection nor remission of seizures influenced the nature or evolution of the psychosis. Subjectively the patients functioned better in activities of daily living and freedom from seizures improved integration into psychiatric treatment facilities. With appropriate psychiatric intervention, patients with chronic psychosis and refractory epilepsy can participate in presurgical investigation successfully, and can undergo surgery uneventfully.

Adult↗

PubMed2001

Absence of sleep spindles in human medial and basal temporal lobes.

All-night recordings from subdural electrocorticographic (ECoG) electrodes on the human medial and basal temporal lobes were analysed to examine spindling activities during sleep. Subjects were three males and three females who were candidates for neurosurgical treatments of partial epilepsy. Subdural electrodes were attached to the medial and basal temporal lobe cortices, allowing ECoG and electroencephalogram from the scalp vertex (Cz EEG) to be recorded simultaneously during all night sleep. In one case, subdural electrodes were attached also on the parietal lobe. Fast Fourier transformation (FFT) analyses were performed on the ECoG and Cz EEG signals. No organized sleep spindles or sigma band (12-16 Hz) peaks in FFT power spectra were observed from the medial or basal temporal lobes of the non-epileptogenic hemispheres during non-rapid eye movement (NREM) sleep. In a case with parietal electrodes, organized spindle bursts were observed in parietal signals synchronized with Cz spindles. Although delta band (0.3-3 Hz) power from both the medial and basal temporal lobes fluctuated across each night as expected, sigma activity changed little. However, 14 Hz oscillatory bursts were observed in the medial basal temporal lobe of epileptogenic hemisphere in two cases and bilaterally in one case during not only NREM sleep but rapid eye movement (REM) sleep and wakefulness. From the present study we conclude that sleep spindle activities are absent in the medial and basal temporal lobes. Fourteen Hz oscillatory bursts observed from the medial or basal temporal lobe in some cases were not considered to be sleep spindles since they also appeared during REM sleep and wakefulness. These waveforms could have originated due to epileptic pathology, since they frequently appeared in epileptic regions.

Adult↗

PubMed1998

Failure of standard magnetic resonance imaging in patients with refractory temporal lobe epilepsy.

OBJECTIVE: To compare the sensitivity of standard magnetic resonance imaging (MRI) scans done outside an epilepsy center with that of special protocol MRI scans done at an epilepsy center in delineating relevant lesions of the temporal lobe. SUBJECTS: Eighty-four consecutive patients who had temporal lobe resections for refractory temporal lobe epilepsy between January 1, 1993, and February 1, 1996. DESIGN: The reports of findings on standard MRI scans done outside an epilepsy center were compared with the findings of special protocol MRI scans done with 1.5-mm T1-weighted coronal and 3-mm T2-weighted coronal images (no gaps) on a 1.5-T system. Both sets of MRI findings were compared with findings on histologic examination of the resected tissue. RESULTS: Of the 84 patients, 51 had standard MRI scans done outside an epilepsy center; of these, there were 34 patients with normal results, 10 with tumors, 2 with vascular malformations, 2 with hippocampal atrophy, 2 with unclassified abnormalities, and 1 with cortical malformation. In 32 of the 34 patients with normal results of an MRI scan done outside an epilepsy center, abnormalities were found on our special protocol MRI scans. These included hippocampal atrophy in 27 patients, tumors in 2, and cortical malformations in 1. Additionally, all 17 of the abnormalities detected on the standard MRI scans done outside the epilepsy center were identified on our special protocol MRI scans. Important pathologic abnormalities of the temporal lobe were identified in 16 (35%) of the 46 patients with standard MRI scans done outside an epilepsy center and in 44 (96%) with our special protocol MRI scans. In the 29 patients for whom adequate surgical specimens were available and results of standard MRI scans were normal, our special protocol MRI scans showed the abnormality in 27 (93%). CONCLUSIONS: Conventional neuroimaging studies are inadequate for diagnosing hippocampal sclerosis although they fairly readily detect low-grade tumors and vascular malformations. Magnetic resonance imaging scans for the evaluation of patients with refractory temporal lobe epilepsy should be done with a special temporal lobe protocol and read by physicians experienced with the findings in hippocampal sclerosis. Health care dollars are wasted on neuroimaging done for refractory temporal lobe epilepsy outside epilepsy centers.

Atrophy↗

PubMed2002

The neurodevelopmental impact of childhood-onset temporal lobe epilepsy on brain structure and function.

PURPOSE: To characterize the neurodevelopmental correlates of childhood-onset temporal lobe epilepsy on brain structure and cognition compared with late-onset chronic temporal lobe epilepsy and healthy controls. METHODS: Healthy controls (n = 62) and patients with early (n = 37) versus late (n = 16) age at onset of temporal lobe epilepsy were compared with high-resolution quantitative magnetic resonance imaging (MRI) volumetrics and comprehensive neuropsychological assessment. RESULTS: Patients with childhood-onset temporal lobe epilepsy (mean onset age, 7.8 years) exhibited widespread compromise in neuropsychological performance and substantial reduction in brain tissue volumes extending to extratemporal regions compared with healthy controls and late-onset temporal lobe epilepsy patients (mean onset age, 23.3 years). Most evident was reduced total white-matter volume among the childhood-onset patients. Reduction in brain tissue volume, especially total white-matter volume, was associated with significantly poorer cognitive status, attesting to the clinical significance of the volumetric abnormalities. CONCLUSIONS: Childhood-onset temporal lobe epilepsy appears to be associated with an adverse neurodevelopmental impact on brain structure and cognition that appears generalized in nature and especially evident in white-matter tissue volume.

Adolescent↗

PubMed1993

The cortical topography of temporal lobe hypometabolism in early Alzheimer's disease.

Alzheimer's disease (AD) is characterized by a pathological process with specific predilection for association neocortex and the mesial temporal lobes. Recently developed high-resolution positron emission tomographs (PET) are able to quantitate regional cerebral metabolic rates for glucose (rCMRglc) in these brain regions and map the distribution of the metabolic consequences of Alzheimer pathology. In order to evaluate the relative involvement of mesial and neocortical temporal lobe brain regions in AD, we studied 22 AD patients, 11 of whom were mildly demented and 11 of whom were moderately demented in comparison to 8 age-matched control subjects. We used a PET instrument with 2.6 mm in-plane resolution and quantitated rCMRglc in anterior, middle, and posterior temporal neocortex, visual association cortex, primary visual cortex, and mesial temporal cortex. Although the moderately demented AD patients showed significantly lower metabolic rates than controls in visual association cortex and all temporal lobe regions except right anterior temporal neocortex, the mildly demented patients were different from the controls in only middle temporal neocortex. Considerable variability was found in the relative involvement of mesial temporal lobes and temporal neocortex in the AD patients, however, as shown by greater variance of a ratio of mesial temporal lobe rCMRglc to temporal neocortical rCMRglc (MES/NEO ratio) in the AD patients than the controls. A series of stepwise multiple regressions showed that this ratio was related to patient cognitive symptomatology, with more severely memory-impaired patients showing lower MES/NEO ratios, while patients with visuospatial disturbances showed higher MES/NEO ratios. In addition, the only biological variable that was related to this ratio was patient age, with older patients showing lower MES/NEO ratios. These results indicate that mesial temporal lobe structures are not invariably the earliest nor the most severely metabolically involved brain regions in AD and that the relative involvement of the mesial and neocortical temporal lobe is related to the patient's cognitive symptoms and age.

Aged↗

PubMed2001

The hippocampal contribution to verbal fluency in patients with temporal lobe epilepsy.

We report the effects of hippocampal and non-hippocampal temporal-lobe dysfunction on verbal fluency performance. Quantitative aspects of semantic and phonemic fluency performance were examined in 46 patients with right- or left-temporal-lobe epilepsy and 20 healthy controls. A pattern of fewer words generated on semantic rather than phonemic fluency tasks was found among patients with damage to hippocampal structures. This pattern was not obtained in patients with non-hippocampal temporal-lobe damage, suggesting that the hippocampus plays a crucial role in semantic fluency performance. An interesting lateralization effect was obtained. Among patients with left temporal-lobe involvement, fluency performance was impaired regardless of whether the hippocampus was involved. In contrast, among patients with right temporal-lobe involvement, fluency performance was impaired only when the hippocampus was involved.

Adult↗

PubMed2000

Wisconsin Card Sorting performance in patients with temporal lobe epilepsy: clinical and neuroanatomical correlates.

PURPOSE: A sizable proportion of patients with temporal lobe epilepsy (TLE) display impairments on tests of executive function. Previous studies have suggested several factors that may explain such performance, including the presence of hippocampal sclerosis, electrophysiological disruption to extratemporal regions, and early age of seizure onset. However, no clear determinants have been found that consistently explain such executive dysfunction. The present study investigated the contribution of several clinical variables and temporal lobe neuroanatomic features to performance on the Wisconsin Card Sorting Test (WCST) in a series of patients with TLE. METHODS: Eighty-nine patients with lateralized TLE (47 left, 42 right) were examined. Seventy-two patients from this series underwent anterior temporal lobectomy (ATL). Regression analysis was used to examine the effects of age, education, age at seizure onset, seizure duration, seizure laterality, history of secondary generalized seizures, and MRI-based volumes of the right and left hippocampi on preoperative WCST performance (number of categories completed, perseverative errors). Further univariate analyses examined whether the presence of bilateral hippocampal sclerosis, mesial temporal lobe abnormalities beyond the hippocampus, or temporal neocortical abnormalities affected preoperative WCST performance. In addition, we examined whether becoming seizure free after ATL affected change in WCST performance. RESULTS: Overall regression analysis was not significant. However, an examination of individual partial correlations revealed that patients with a history of secondary generalized seizures performed more poorly on the preoperative WCST than did patients without such history. In addition, patients who were seizure free after ATL did not exhibit better WCST outcome than patients who did not become seizure free. The presence of bilateral hippocampal sclerosis, extrahippocampal mesial temporal atrophy, or temporal neocortical lesions did not affect WCST performance. CONCLUSIONS: These results indicate that the presence of temporal lobe structural abnormalities do not significantly affect executive function as measured by the WCST. The present study does suggests that the critical determinants of WCST performance in patients with TLE lie outside the temporal lobe and likely relate to metabolic disruption to frontostriatal neural network systems.

Adult↗

PubMed2004

Face and facial expression memory in temporal lobe epilepsy patients: preliminary results.

Right temporal lobe structures are involved in face and facial expression processing and in mnestic functions. Face and facial expression memory was investigated in 15 patients with left (LTLE) and 18 patients with right (RTLE) temporal lobe epilepsy as well as 13 healthy controls. Pairs of pictures combining four faces and four emotions had to be matched according to face identity or facial expression. In the memory tasks, the two pictures of a pair were divided by a memory interval of 2000 milliseconds, whereas in the perception tasks (control condition) both pictures were presented simultaneously. RTLE patients had significantly lower scores than healthy controls in face memory. LTLE patients had significantly lower scores than healthy controls in face and facial expression memory. The data confirm impaired face memory in RTLE patients and show that LTLE patients display deficits in face as well as in facial expression memory. Results are discussed according to functional reorganization, memory strategies, perception performance, naming problems, and group characteristics.

Adult↗

PubMed2004

"Tangential" resection of medial temporal lobe arteriovenous malformations with the orbitozygomatic approach.

OBJECTIVE: Arteriovenous malformations (AVMs) of the medial temporal lobe are usually resected through subtemporal-transcortical approaches that provide a trajectory that is perpendicular to the plane of the AVM. The pterional approach is sometimes used for AVMs in the uncus and amygdala, but it is not recommended for AVMs in the hippocampal region because it provides a "tangential" approach with limited access to posterior feeding arteries and draining veins. The orbitozygomatic approach enhances exposure along this tangential trajectory and was used in a consecutive series of 10 patients to determine its advantages. METHODS: During a 5.7-year period, 43 patients underwent resection of temporal lobe AVMs, 10 of which were located in the medial temporal lobe (amygdala and uncus [Region A] or hippocampus, parahippocampus, and fusiform gyrus [Region B]). AVMs were evenly distributed by region and by hemispheric dominance and included two Spetzler-Martin Grade IV lesions. An orbitozygomatic approach was used in all cases. RESULTS: Complete resection was accomplished in nine patients, and one patient underwent multimodality management with postoperative stereotactic radiosurgery. Good outcomes (Rankin outcome score <or=2) were observed in all patients, and six patients were improved neurologically at late follow-up (mean, 1.3 yr). No permanent language deficits were produced by this approach. CONCLUSION: The orbitozygomatic approach maximizes the exposure of the tangential approach to medial temporal lobe AVMs and has advantages over traditional lateral approaches. It provides early access to critical feeding arteries from the anterior choroidal artery, posterior cerebral artery, and posterior communicating artery; it minimizes temporal lobe retraction and risk to the vein of Labbé; and it avoids transcortical incisions or lobectomy that might impact language and memory function. For these reasons, it may be the optimal approach for small- and medium-sized compact AVMs in the dominant medial temporal lobe.

Adolescent↗

PubMed1993

Neuropsychological correlates of MRI temporal lobe abnormalities in schizophrenia.

OBJECTIVE: The authors evaluated the neuropsychological correlates of temporal lobe abnormalities in schizophrenic patients. METHOD: Fifteen schizophrenic patients underwent assessment of memory, by the Wechsler Memory Scale--Revised, and abstraction/categorization, by the similarities subtest of the Wechsler Adult Intelligence Scale--Revised and the Wisconsin Card Sorting Test. Neuropsychological tests of motor and constructional functions were used as control tasks. The patients also underwent magnetic resonance imaging (MRI) studies in which new neuroimaging techniques were used to derive measurements of volume and three-dimensional surface renderings of temporal lobe structures. RESULTS: Spearman rank-order correlations indicated significant associations between poor scores on tests of verbal memory, abstraction, and categorization and reduced volume in temporal lobe structures, including the parahippocampal gyrus and posterior superior temporal gyrus (left and right). By contrast, performance on tests of visual memory and on control tasks was not correlated with MRI temporal lobe abnormalities. CONCLUSIONS: These findings suggest a significant but modest relation between reduced volume in specific temporal lobe regions and neuropsychological deficits in abstraction, categorization, and verbal memory, all of which may reflect a dysfunctional semantic system in schizophrenia.

Adult↗

PubMed2004

[Surgical treatment of medically intractable temporal lobe epilepsy--fundamental technique and tips for implantation of intracranial electrodes and tailored temporal lobectomy].

We report a tailored temporal lobectomy for surgical treatment of medically intractable temporal lobe epilepsy. Surgery was conducted on 30 patients with temporal lobe epilepsy, 15 of whom required intracranial electrode placement. A precise skin incision had to be designed when subdural electrodes were placed, taking into consideration the electrodes' size and where they should be placed. Drawing of the Sylvian line and Rolandic line using Taylor's method on the patient's scalp provided useful information to determine the place of craniotomy. Fundamental surgical techniques and tips are described, including how to open the inferior horn after minimal removal of the lateral temporal cortex, and the introduction of a newly developed needle electrode combined with the ring type for recording electrocorticography from the exposed hippocampal surface. Twenty-three patients with mesial temporal epilepsy were treated surgically and the surgical results of 20 patients followed-up for more than one year (mean 44 months)were analyzed. Eighteen patients (90%)were seizure free (Engel class I), and 2 patients were categorized as having a significant seizure reduction (class III). Despite the good surgical results to date, further follow-up is needed to evaluate the long-term surgical effects.

Amygdala↗

PubMed1999

Hippocampal involvement in spatial and working memory: a structural MRI analysis of patients with unilateral mesial temporal lobe sclerosis.

Forty-seven patients with unilateral temporal lobe epilepsy (TLE) were investigated on the Nine-Box Maze. The task was designed to compare working memory and spatial mapping theories of the functions of the hippocampus and provide measures of spatial, object, working, and reference memory. The results extended our previous findings in a larger group of patients. Spatial memory deficits across both working and reference memory conditions were found in patients with a right epileptogenic focus. There was no evidence of an object working memory deficit, but a nonlateralized impairment in object reference memory was revealed, which is consistent with our previous findings. The pattern of results was confirmed in a subgroup of 33 patients with unilateral atrophy localized to the hippocampus and parahippocampal gyrus, as verified by volumetric analysis of magnetic resonance images. In addition spatial memory errors significantly correlated with volumetric measures of mesial temporal lobe structures and not with measures of the remaining temporal cortex. In contrast, object reference memory errors correlated with volumetric measures of the temporal cortex and not with mesial temporal lobe structures. These findings support a specialized role for the right hippocampal region in spatial memory.

Adult↗

PubMed1997

Separate neural bases of two fundamental memory processes in the human medial temporal lobe.

The participation of medial temporal-lobe structures in memory performance was examined by functional magnetic resonance imaging of local blood oxygenation level-dependent signals. Signals were measured during encoding into memory complex scenes or line drawings and during retrieval from memory of previously studied line drawings or words. Encoding tasks yielded increased signals for unfamiliar information in a posterior medial-temporal region that were focused in the parahippocampal cortex. Retrieval tasks yielded increased signals for successfully remembered information in an anterior medial-temporal region that were focused in the subiculum. These results indicate that separate components of the human medial temporal-lobe memory system are active during distinct memory processes.

Adult↗

PubMed2000

Vascular steal model of human temporal lobe epileptogenicity: the relationship between electrocorticographic interhemispheric propagation time and cerebral blood flow.

Human temporal lobe epileptogenicity (i.e. seizure frequency) depends on epileptic and non-epileptic cerebral blood flow (CBF). Increasing non-epileptic cortical CBF is associated with reduction in epileptic cortical CBF. Seizure frequency increases logarithmically with non-epileptic cortical CBF increase and epileptic cortical CBF reduction. A model of human temporal lobe epileptogenicity is derived from the mathematical equivalence to the logarithmic function of seizure frequency of (a) epileptic and non-epileptic CBF differential and (b) electrocorticographic (ECoG) interhemispheric propagation time (IHPT). The vascular steal model of human temporal lobe epileptogenicity suggests that a small CBF redistribution from non-epileptic to epileptic cortex should produce substantial reduction in temporal lobe seizure frequency in association with prolongation of IHPT. The equivalence of these CBF and ECoG parameters to the logarithmic function of seizure frequency suggests that the interhemispheric temporal lobe perfusion gradient and ECoG propagation time may be involved in the fundamental perturbation responsible for human temporal lobe epileptogenicity.

Arteriovenous Malformations↗

PubMed1997

Heinrich Klüver and the temporal lobe syndrome.

Heinrich Klüver and Paul Bucy described a constellation of symptoms in monkeys following large resections of the temporal lobe that they termed the "temporal lobe syndrome"; now commonly referred to as the Klüver-Bucy syndrome. The aim of this paper is threefold: (1) to review Heinrich Kluver's behavioral studies on monkeys that led up to his temporal lobe experiments with Paul Bucy; (2) to understand why Brown and Schäfer dismissed the behavioral changes in temporal lobe monkeys they had observed fifty years prior to the studies of Klüver and Bucy; and (3) to show that Klüver's phenomenologically motivated conceptual paradigm helped to unify both neuropsychological and neuroanatomical theories regarding the visual and emotive functions of the non-human primate temporal lobe.

Animals↗

PubMedDate not supplied

Neuropsychological assessment of an 8-year-old child following excision of a right temporal lobe oligodendroglioma.

A case of right temporal lobe oligodendroglioma in an 8-year-old female is reported. This case is unusual, because of the rarity of this type of tumour in children, because it was accompanied by seizure activity which is atypical, and because it highlights the difficulties in diagnosis. Prior to diagnosis, the background had included normal early development, followed by gradual development of partial complex seizures with poor response to medication in the absence of clear findings on EEG or CT. Considered to have been present prior to 1 year of age, the tumour was purported to be the aetiological base for seizure activity, which ceased after surgical excision. Post-surgical difficulties with academic progress and behaviour resulted in referral for neuropsychological evaluation, which revealed lowered overall cognitive functioning with deficits in processing speed, abstract verbal reasoning, concept formation, visual perception, visual reasoning, scanning, attention, memory, academic attainment and learning, and clerical motor speed. Behavioural functioning revealed impairment in social skills, irritability, impulsivity, and mood changes. The relative contributions of medication (adverse reaction and toxicity), long term seizure activity, early age of onset, and presence/excision of tumour are difficult to ascertain specifically. Findings appear consistent with those of right temporal lobe brain injury.

Brain Neoplasms↗