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MR in temporal lobe epilepsy: analysis with pathologic confirmation.

PURPOSE: We evaluated the MR findings in patients with temporal lobe epilepsy to determine the predictive value of MR imaging in assessing patient outcome. METHODS: MR studies from 186 of 274 consecutive patients who underwent temporal lobectomy for intractable epilepsy were reviewed retrospectively. Images were interpreted by an experienced neuroradiologist, who was blinded to the side of seizure activity and to pathologic findings. RESULTS: MR imaging exhibited 93% sensitivity and 83% specificity in detecting hippocampal/amygdalar abnormalities (n = 121), and 97% sensitivity and 97% specificity in detecting abnormalities in the rest of the temporal lobe (n = 60). Abnormal high signal of the hippocampus on T2-weighted images had a sensitivity of 93% and specificity of 74% in predicting mesial temporal sclerosis (n = 115). The presence of hippocampal atrophy on MR correlated with the duration of seizures. Sensitivity and specificity of MR imaging in detecting temporal lobe tumors (n = 42) were 83% and 97%, respectively, based on abnormal signal and mass effect. After surgery, 63% of patients were seizure free and 28% had a significant reduction of seizure frequency at an average of 24 months (range, 12 to 78 months) after surgery. Patients with a single lesion in the anterior temporal lobe or hippocampus/amygdala had a better outcome than patients with multiple lesions (n = 22). Interrater agreement varied from 0.4 to 0.93, with best agreement for tumors or abnormal hippocampal signal on T2-weighted images. CONCLUSION: MR imaging is highly sensitive in detecting and locating abnormalities in the temporal lobe and the hippocampus/amygdala in patients with temporal lobe epilepsy. Hippocampal atrophy appears to correspond to the duration of seizure disorder.

Adult↗

[Temporal lobe damage as pitfalls at subtemporal transtentorial approach (author's transl)].

It is essential to make a proper approach to the lesion site and retract brain, thereby securing an adequate field of vision, upon performing operations on patients for lesions of deep temporal lobe and tentorium. Although subtemporal transtentorial approaches to tumors in the tentorium, pyramis and cerebellopontine angle have been described by a number of workers, further studies have to be made on temporal lobe damage as a pitfall since only a few reports have been published to date. We have therefore examined the possible factors which are responsible for temporal lobe damage and brain swelling in six cases in which subtemporal transtentorial approaches were made. We have encountered two cases of meningioma of the pyramis and tentorium growing in the middle and posterior fossa, one case each of acoustic neurinoma and trigeminal neurinoma located in the middle and posterior fossa, one case of aneurysm at a marginal branch of the superior cerebellar artery and one case of arteriovenous malformation of the deep temporal lobe. Temporal lobe damage was observed in two of these cases during operation and in post-operative CT scans. Although no particular symptoms were noted, CT scan revealed temporal lobe damage in one case. One of the main factors responsible for temporal lobe damage is cutting major veins, namely inferior cerebral vein, transverse sinus, etc. However, no damage was resulted from cutting superior petrosal sinus. Intermittent release of the brain retractor and repeated use of hyperosmotic solution including ventricular drainage are recommended for preventing temporal lobe damage.

Adolescent↗

Ictal urinary urge indicates seizure onset in the nondominant temporal lobe.

The authors describe six patients with medically refractory temporal lobe epilepsy whose seizures were characterized by an aura of ictal urinary urge. All seizures originated in the nondominant temporal lobe as evidenced from interictal spikes, ictal EEG, and MRI. Ictal SPECT, which was obtained in two patients, showed a hyperperfusion of the insular cortex, indicating a critical role of the insula for the generation of this symptom. Ictal urinary urge represents a new lateralizing sign indicating a seizure onset in the nondominant temporal lobe.

Adolescent↗

Correlation of severity of FDG-PET hypometabolism and interictal regional delta slowing in temporal lobe epilepsy.

PURPOSE: We investigated the association of severity of hypometabolism detected by positron emission tomography (PET) with [(18)F]fluorodeoxyglucose (FDG) and persistence of interictal EEG focal slowing in patients with refractory temporal lobe epilepsy. METHODS: Eighty temporal lobes of 40 consecutive patients with intractable temporal lobe epilepsy (mean age, 43.5 years) were studied. All patients underwent video-EEG monitoring, magnetic resonance imaging (MRI), and FDG-PET. Patients with either normal MRI or with unilateral mesial temporal sclerosis, but no other structural abnormality, were included. Interictal EEG delta slowing was graded as none, infrequent (one episode or less/hour), intermediate (more than one episode/hour), or continuous. PET hypometabolism was graded as none, mild, moderate, or severe. RESULTS: The severity of temporal lobe hypometabolism with PET was significantly correlated with the amount of delta activity in the interictal EEG, independent of MRI findings (Spearman r = 0.46; p < 0.0005). CONCLUSIONS: This observation suggests related underlying pathophysiologic mechanisms for metabolic and electrical dysfunction in temporal lobe epilepsy.

Adult↗

[Prognostic factor for medical control for seizures in patients with radiologic evidence for mesial temporal lobe sclerosis].

INTRODUCTION: Patients with mesial temporal lobe sclerosis (MTS) usually have suffered a brain insult during early childhood, a febrile convulsion in most cases. Complex partial seizures start after a seizure free period of variable duration. These complex partial seizures have an stereotypic semiology. Often, these seizure are not controlled with medical therapy, previous studies shows a rate of control not superior of 30%. AIM. To know the prognosis for medical control of patients with MTS and to find related factors. PATIENTS AND METHODS: The clinical characteristics of 51 patients with temporal lobe epilepsy and radiologic evidence of MTS (hippocampus atrophy or increased signal on T2 or Flair magnetic resonance sequences). RESULTS: 51 patients, of them 17 (34%) were men. 17 (34%) presented right MTS, 30 (60%) left MTS and 2 (4.3%) bilateral MTS. 16 patients (34.8%) referred autonomic aura, 14 (27.5%) psychic aura, 4 (7.8%) dysphasia and 13 (25.5%) no aura, in 2 (3.9%) aura were mixed: autonomic psychic. The aura was associated to the lesion laterality (p= 0.023) and to the reference of some antecedent of cerebral aggression during early childhood (p= 0.011). Concerning to the seizure control, 15 patients (29.2%) were seizure free in the last 6 month and 36 (70.6%) remaining uncontrolled. The associated factors to the medical control were the age of onset (p= 0.024) and the duration of the epilepsy (p= 0.018). CONCLUSIONS: Around 29% of patients with MTS can be controlled with medical therapy. Seizure control is related with later age of onset and short duration of the epilepsy

Adult↗

Rhythmic ictal nonclonic hand (RINCH) motions: a distinct contralateral sign in temporal lobe epilepsy.

PURPOSE: To describe a new ictal sign in temporal lobe seizures-rhythmic ictal nonclonic hand (RINCH) motions and to determine its lateralizing significance and other ictal manifestations associated with it. METHODS: We identified 15 patients with temporal lobe epilepsy who demonstrated RINCH motions and reviewed video-EEG recordings of all their seizures. We analyzed the epilepsy characteristics and all clinical features of recorded seizures, with particular attention to RINCH motions. RESULTS: RINCH motions were unilateral, rhythmic, nonclonic, nontremor hand motions. RINCH motions were usually followed by posturing, sometimes with some overlap. They involved the hand contralateral to the temporal lobe of seizure onset in 14 of 15 patients. CONCLUSIONS: RINCH motions are a distinct ictal sign that could be considered a specific type of automatism. They appear to be a lateralizing contralateral sign and are associated with dystonic posturing in temporal lobe epilepsy.

Adult↗

Neuronal activity in the human medial temporal lobe during recognition memory.

Human medial temporal lobe neuronal activity and event-related potentials were recorded during the following behaviours: contextual recognition of words and faces, semantic discrimination of nonwords from words, and discrimination of stimulus classes based on perceptual attributes. Three distinct classes of behavioural correlates of unit activity were demonstrated by visual inspection of peristimulus histograms and by nonparametric statistics: (1) neuronal excitation during a keypress related to the subject's choice; (2) specific and nonspecific excitation to words; (3) excitation or inhibition to rare stimuli in a sensory discrimination task. Responses specifically to familiar (as opposed to unfamiliar) words or faces, or to tasks requiring recent memory per se were never seen. Keypress excitation was relatively common (32/76 units) and occurred regardless of whether the keypress target was a repeated or nonrepeated word, or the task required recent or remote semantic memory. In a more complex recognition task utilizing two responses and an imperative cue for the patient's response, units with prior keypress excitation failed to generate the response. This suggests that keypress excitation is not strictly tied either to response choice or to generation. The onset latencies and temporal relationship to event-related potentials of the nonspecific and specific excitation to words and the excitation to rare stimuli suggest that they represent contextual encoding of stimuli. Similar evidence suggests that the inhibition to rare stimuli represents inhibitory processes terminating contextual encoding. Thus human medial temporal lobe neurons seem to contribute information during successive stages of a cognitive stimulus-response task: contextual encoding, closure and response-selection.

Action Potentials↗

Medial temporal lobe atrophy and memory dysfunction as predictors for dementia in subjects with mild cognitive impairment.

To determine whether the medial temporal lobe is atrophic in subjects with mild cognitive impairment, and whether atrophy of this structure is a better predictor of dementia than memory dysfunction. Forty-five noninstitutionalized subjects aged 65-85 years were randomly selected from a population based study to obtain a sample with Alzheimer's disease (AD; n = 7), and a clinically nondemented sample (n = 38). Twenty of the latter subjects displayed some cognitive impairment and fulfilled CAMDEX criteria for "minimal dementia." Coronal T1-weighted magnetic resonance imaging was used to visualize the medial temporal lobe. The volume of the parahippocampal gyrus and hippocampus was measured, and medial temporal lobe atrophy was assessed qualitatively. The memory subscore from the CAMCOG was used as a measure of memory functioning. The follow-up period was 3 years. Nine subjects who were diagnosed as being minimally demented at baseline met the criteria for AD during follow-up. At baseline the volume of the parahippocampal gyrus of these subjects was smaller than that of the other subjects with minimal dementia. The memory score was the best predictor of clinical outcome. All medial temporal lobe measures increased the accuracy of prediction compared with only the memory score, by reducing the number of false-negative classifications of dementia. Severe medial temporal lobe atrophy is present even in some subjects with mild cognitive impairment and is an indicator of subsequent AD. The absence of medial temporal lobe atrophy, however, does not exclude the development of dementia. In the majority of subjects memory impairment was a better predictor of dementia than atrophy of the medial temporal lobe. The combination of the two increased predictive accuracy. Nondemented subjects with severe atrophy of the medial temporal lobe could be enrolled in drug trials aimed at slowing the progression of AD.

Aged↗

Cognitive function of patients with nasopharyngeal carcinoma with and without temporal lobe radionecrosis.

BACKGROUND: Radiotherapy is the primary treatment for nasopharyngeal carcinoma, and temporal lobe necrosis is observed in about 7% of patients after radiotherapy. Although some studies reported that these patients demonstrated cognitive impairment after radiotherapy, it is still unclear if the cognitive deficits are related to the radiation exposure or the radiation-induced necrosis. OBJECTIVE: To compare the cognitive function of patients with and without temporal lobe necrosis after radiotherapy for nasopharyngeal carcinoma. METHODS: A comprehensive neuropsychological battery was administered to 53 patients with nasopharyngeal carcinoma who had completed their radiotherapy at least 1 year previously. As evidenced by magnetic resonance imaging, 31 patients developed necrosis after treatment. Thirty-one age- and education-matched individuals were recruited as normal control subjects. RESULTS: Whereas the performance of patients without temporal lobe necrosis was similar to that of normal control subjects, patients with temporal lobe necrosis demonstrated significant impairment on tests of verbal (P<.001) and visual memory (range, P<.001 to P =.03), language (range, P<.001 to P =.01), motor ability (P =.02), planning (P =.02), cognitive ability (P =.007), and abstract thinking (range, P =.009 to P =.04). However, the performance of patients with necrosis on tests of general intelligence (range, P =.08 to P =.15), attention (range, P =.06 to P =.55), and visual abilities (range, P =.06 to P =.47) was not significantly different from that of normal control subjects and patients without necrosis. CONCLUSIONS: Radiotherapy for nasopharyngeal carcinoma seemed to have adverse but insignificant effects on the cognitive functions of the patients. However, for patients who developed temporal lobe necrosis after radiotherapy, memory, language, motor ability, and executive functions were significantly impaired, although their general intelligence remained relatively intact.

Cognition Disorders↗

Dissociable medial temporal lobe contributions to social memory.

Medial temporal lobe structures such as the hippocampus have been shown to play a critical role in mnemonic processes, with additional recruitment of the amygdala when memories contain emotional content. Thus far, studies that have examined the relationship between amygdala activity and memory have typically relied on emotional content of the kind that is rarely encountered in day-to-day interactions. The present event-related functional magnetic resonance imaging study investigates whether amygdala activity supports emotional memory during the more subtle social interactions that punctuate everyday life. Across four training sessions, subjects learned common first names for unfamiliar faces in the presence or absence of additional contextual information that was positive, negative, and neutral in valence (e.g., "Emily helps the homeless," "Bob is a deadbeat dad," "Eric likes carrots"). During scanning, subjects performed a yes/no recognition memory test on studied and novel faces. Results revealed a functional dissociation within the medial temporal lobe. Whereas a region within the right hippocampus responded strongly to all faces that had been paired with a description, regardless of its valence, activity in the right amygdala was uniquely sensitive to faces that had been previously associated with emotional descriptions (negative and positive > neutral). This pattern of activity in the amygdala was preserved even when the emotional contexts associated with faces could not be explicitly retrieved, suggesting a role for the amygdala in providing a nonspecific arousal indicator in response to viewing individuals with emotionally colored pasts.

Adolescent↗

Patterns of temporal lobe atrophy in semantic dementia and Alzheimer's disease.

Volumetric magnetic resonance imaging analyses of 30 subjects were undertaken to quantify the global and temporal lobe atrophy in semantic dementia and Alzheimer's disease. Three groups of 10 subjects were studied: semantic dementia patients, Alzheimer's disease patients, and control subjects. The temporal lobe structures measured were the amygdala, hippocampus, entorhinal cortex, parahippocampal gyrus, fusiform gyrus, and superior, middle, and inferior temporal gyri. Semantic dementia and Alzheimer's disease groups did not differ significantly on global atrophy measures. In semantic dementia, there was asymmetrical temporal lobe atrophy, with greater left-sided damage. There was an anteroposterior gradient in the distribution of temporal lobe atrophy, with more marked atrophy anteriorly. All left anterior temporal lobe structures were affected in semantic dementia, with the entorhinal cortex, amygdala, middle and inferior temporal gyri, and fusiform gyrus the most severely damaged. Asymmetrical, predominantly anterior hippocampal atrophy was also present. In Alzheimer's disease, there was symmetrical atrophy of the entorhinal cortex, hippocampus, and amygdala, with no evidence of an anteroposterior gradient in the distribution of temporal lobe or hippocampal atrophy. These data demonstrate that there is a marked difference in the distribution of temporal lobe atrophy in semantic dementia and Alzheimer's disease. In addition, the pattern of atrophy in semantic dementia suggests that semantic memory is subserved by anterior temporal lobe structures, within which the middle and inferior temporal gyri may play a key role.

Aged↗

Temporal lobe involvement in Japanese encephalitis: problems in differential diagnosis.

BACKGROUND AND PURPOSE: On MR imaging and CT, Japanese encephalitis (JE) shows lesions in the thalami, substantia nigra, basal ganglia, cerebral cortex, cerebellum, brain stem, and white matter, whereas temporal lobe involvement is characteristically seen in Herpes simplex encephalitis (HSE). Temporal lobe involvement in JE may cause problems in differentiating it from HSE. We undertook this study to show the temporal lobe involvement pattern in JE and highlight differentiating features from temporal lobe involvement in HSE. METHODS: Sixty-two patients with JE underwent CT or MR imaging or both. MR imaging was done in 53 and CT in 53. The diagnosis of JE was confirmed by cerebrospinal fluid (CSF) IgM enzyme-linked immunosorbent assay. RESULTS: Eleven (17.7%) patients showed temporal lobe involvement with abnormal MR imaging in all. All the patients showed hippocampal involvement. Two patients showed extension of lesions into the amygdala and uncus with insular involvement in 1. The rest of the temporal lobe was spared. All patients had thalamic and substantia nigra involvement with basal ganglia involvement in 7. Six of 9 CT scans were abnormal and the temporal lesions were seen in 2. CONCLUSIONS: The temporal lobe involvement pattern is fairly characteristic and mostly involves the hippocampus, usually sparing the rest of the temporal lobe. This and the concurrent involvement of the thalami, substantia nigra (SN), and basal ganglia allow differentiation from HSE. However, if the temporal lobe involvement is more severe, laboratory tests may be the only way to differentiate it from HSE, and it may be prudent to start antiviral therapy in the interim period.

Adolescent↗

Normal sonographic findings of the infant temporal lobe in coronal sections.

Coronal sonograms of the temporal lobe of the infant brain were obtained using a real time sector scanner with a 5.0 MHz transducer probe. The precise normal anatomy in the coronal sections was determined by correlating with corresponding brain specimens. It was revealed that the spatial arrangement of structures in the medial part of the temporal lobe, i.e. the hippocampal formation and the inferior horn, varied in the three different planes. In the plane through the anterior part of the temporal lobe, these structures were seen as a horizontal lamellar configuration, whereas in the plane through the middle part these structures were depicted as a typical interfolded arrangement. However, the hippocampal formation was barely visible in the plane through the posterior part.

Brain↗

Absence of normal activation of the left anterior fusiform gyrus during naming in left temporal lobe epilepsy.

Patients with left temporal lobe epilepsy (TLE) often have impaired naming. We studied 13 patients with left TLE and 10 healthy control subjects with [(15)O]H2O PET during visual confrontation naming. Statistical mapping detected multiple regions of significant cerebral blood flow increases within individuals. The left fusiform gyrus was activated in nine healthy subjects, but only in two patients with TLE (a significant difference, p < 0.001). Other activation sites were more variable in healthy subjects and those with TLE. Impaired naming ability may be associated with a lack of increased cerebral blood flow in the left fusiform gyrus in TLE.

Adolescent↗

Treatment of temporal lobe epilepsy.

Initial management of patients with temporal lobe epilepsy is with antiepileptic drugs, but these control seizures in only half the patients. Patients refractory to drugs should be evaluated for resective surgery. That evaluation requires identification of a focus of onset of seizures, as well as establishing that the focus is in an area of the brain that can be removed with a low risk of new neurologic deficits. Techniques used in that evaluation, including electroencephalography, imaging, recording form intracranial electrodes, use of the intracarotid amobarbitol perfusion test, and the role of specialized studies such as positron emission tomography, are reviewed, along with the correlation of the findings on that evaluation to the control of seizures after surgery. The different surgical techniques for temporal lobe resections are also reviewed, along with the risks of surgery, particularly to recent memory, and the changes in quality of life following surgery.

Anticonvulsants↗

Verbal memory in left temporal lobe epilepsy: evidence for task-related localization.

We explored the hypothesis that components of verbal memory are subserved by separate temporal lobe structures in patients with temporal lobe structures in patients with temporal lobe epilepsy [correction]. Uptake of 18F-fluorodeoxyglucose (FDG) measured by positron emission tomography, hippocampal volume, and memory for arbitrarily and semantically related verbal paired associates were examined in 27 patients with left temporary lobe epilepsy. Scores from memory tests performed outside the scanner were regressed against normalized resting FDG uptake at each voxel. Significant regression was seen in the left perirhinal cortex (Talaraich coordinates x, y, z: -29, 10, -34; p < 0.05) for arbitrarily related word pairs. For semantically related paired associates, significant regression was present in the left inferior temporal gyrus (x, y, z: -48, -18, -24; p < 0.05). In subsequent analyses, mean FDG uptake within a spherical region of interest centered on the perirhinal peak predicted performance on both tasks. Mean FDG uptake in a region of interest centered on the inferior temporal peak made an additional, independent contribution to memory for semantically related pairs. Hippocampal volumes did not explain any additional variance in memory scores. Our findings indicate that heterogeneity in the left temporal lobe structures mediating verbal memory function, and support the view that the perirhinal cortex is an important mnemonic substrate.

Adolescent↗

Temporal-lobe epilepsy: comparison of CT and MR imaging.

In 50 patients with temporal-lobe epilepsy, CT and MR findings were compared. Axial CT scans were obtained before and after administration of contrast material. Coronal MR imaging was carried out with two spin-echo (SE) sequences with a repetition time of 1600 msec and echo times of 35 or 70 msec (SE 1600/35, SE 1600/70). A focal lesion was detected by CT in 12 cases and by MR in 16 cases. If discrete attenuation or signal abnormalities are also taken into account, CT provided a positive finding in 13 cases and MR imaging in 20 cases. With the exception of a small calcification, all the lesions revealed on the CT scans were also detected on the MR images. Among the examinations assessable for temporal-lobe asymmetry, signs of a unilateral reduction in temporal-lobe size were seen on two of 35 CT scans and on 15 of 38 MR images. In three patients who had temporal-lobe resection, a subsequent comparison was made between CT, MR imaging, and pathology. Histologically proven glial reactions that could not be detected on CT were demonstrated as high-signal-intensity lesions on the SE 1600/70 image. We conclude that MR scanning, with its higher sensitivity, superior image quality, and ability of multiplanar imaging, should be the imaging technique of choice in the diagnosis of temporal-lobe epilepsy.

Adolescent↗

Limbic encephalitis not associated with neoplasm as a cause of temporal lobe epilepsy.

OBJECTIVE: To describe four patients with temporal lobe epilepsy with limbic encephalitis unrelated to neoplasm. METHODS: The authors performed a retrospective evaluation of patient data obtained during presurgical evaluation, with additional CSF analyses, serum analyses, and histopathologic investigations. RESULTS: The patients shared the following clinical features: onset of the disease in young adulthood with subacute onset or exacerbation of frequent intractable temporal lobe seizures, verbal and visual memory deficits, and affective abnormalities. MRI showed variably extended areas of increased T2 signal in limbic structures and adjacent areas. In the histopathologic investigation, chronic inflammation was observed without evidence of a viral origin. There was no evidence of an underlying malignancy. CONCLUSIONS: Nonparaneoplastic limbic encephalitis should be included in the differential diagnosis of adult patients with temporal lobe epilepsy.

Adult↗