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PubMed1994

MRI and brain spect findings in patients with unilateral temporal lobe epilepsy and normal CT scan.

26 patients with temporal lobe epilepsy clinically documented by several abnormal interictal surface EEGs with typical unitemporal epileptiform activity and a normal CT scan were studied. Interictal 99mTC HMPAO brain SPECT and MRI were performed in all subjects. Abnormalities were shown in 61.5% of MRI (n = 16) and 65.4% of SPECT (n = 17). Hippocampal atrophy associated to a high signal on T2-weighted MRI slices suggesting mesial temporal sclerosis was the main finding (n = 12; 75% of abnormal MRI). MRI correlated well to surface EEG in 50% (n = 13). There was also a good correlation between MRI and SPECT in 30.7% (n = 8). SPECT and EEG were in agreement in 57.7% (n = 15). MRI, SPECT and EEG were congruent in 26.9% (n = 7). These results support the usefulness of interictal brain SPECT and MRI in detecting lateralized abnormalities in temporal lobe epilepsy. On the other hand, in two cases, interictal SPECT correlated poorly with surface EEG. This functional method should not be used isolately in the detection of temporal lobe foci. MRI is more useful than CT as a neuroimaging technique in temporal lobe epilepsy. It may detect small structural lesions and mesial temporal lobe sclerosis which are not easily seen with traditional CT scanning.

Adolescent↗

PubMed1994

[Lateralization of the epileptogenic area by magnetic resonance imaging in temporal lobe epilepsy].

We studied 5 patients with medically refractory temporal lobe epilepsy using special methods of MRI, in order to localize the epileptogenic area. Coronal sequences were obtained with 5 mm sections from the posterior margin of the brainstem to the base of the frontal lobe using: "Inversion recovery T1" (TR = 2500 msec, TE = 26 msec, T1 = 600 msec) to analyse loss of internal structure and atrophy of the hippocampus, and morphology of the temporal lobe; and Spin-echo T2w (TR = 250 msec, TE = 120 msec) looking for abnormal high intensity signal. In two cases with left focal EEG the MRI showed atrophy, loss of internal structure and abnormal high intensity signal in the hippocampus, and atrophy of the anterior temporal lobe, ipsilaterally. One case with independent bilateral foci at the EEG showed atrophy, loss of internal structure and abnormal high intensity signal in the right hippocampus. Other case with right focal EEG showed bilateral atrophy of the anterior temporal lobes. Another case was normal. We conclude that this methodology can facilitate the surgical indication in temporal lobe epilepsy.

Adult↗

PubMed1990

Differential sensitivity to context in diencephalic and temporal lobe amnesia.

This study compares diencephalic and temporal lobe amnesics on a memory task in which the encoding of temporal context is essential for accurate performance. On trial 1 subjects were shown four pictures and asked to discriminate them from distractors one minute later. On the three subsequent trials the same procedure was used except that items previously used as distractors became targets and vice versa. The results showed that both groups performed close to ceiling on trial 1. On trials 2, 3, and 4, however, the diencephalic group showed poorer accuracy than the temporal lobe group. These results indicate that the diencephalic amnesics have greater difficulty encoding distinctive contexts across trials 2, 3, and 4 than do the temporal lobe group. Explanations of this difference are discussed briefly.

Alcohol Amnestic Disorder↗

PubMed2000

Interictal EEG and ictal scalp EEG propagation are highly predictive of surgical outcome in mesial temporal lobe epilepsy.

PURPOSE: Surgical outcome in patients with mesial temporal lobe sclerosis (MTS) is worse than that in patients with temporal lobe activity (TLE) with tumors. Previous studies of the ictal EEG focused on ictal EEG onset in scalp EEG or ictal EEG propagation in invasive recordings. Ictal EEG propagation with scalp electrodes has not been reported. METHODS: Ictal scalp EEG propagation patterns were studied in 347 seizures of 58 patients with MTS or nonlesional TLE. Interictal epileptiform discharges (IEDs) and the presence of unilateral mesial temporal lobe atrophy in magnetic resonance imaging (MRI) also were studied in these 58 patients. Forty-nine patients were operated on (minimal follow-up of 1 year). RESULTS: Postoperatively, seizure-free outcome was seen in (a) 82.8% of patients with regionalized EEG seizure without contralateral propagation, but in only 45.5% of patients with contralateral propagation (p = 0.007); (b) 84.6% of patients with 100% IED lateralized to one temporal lobe, but in only 52.2% with <100% unitemporal IED (p = 0.015); (c) 88.9% with 100% unitemporal IED and regionalized ictal EEG combined, 73.7% with one of both variables, and only 33.3% with <100% ipsitemporal IED combined with contralateral ictal EEG propagation (p = 0.007). CONCLUSIONS: Switch of lateralization or bitemporal asynchrony in the ictal scalp EEG and bitemporal IED are most probably an index of bitemporal epileptogenicity in MTS and are associated with a worse outcome.

Adolescent↗

PubMed2002

Pre- and postoperative verbal memory in pediatric patients with temporal lobe epilepsy.

Outcome studies concerning memory after pediatric temporal lobe surgery in the treatment of epilepsy are rare and have not yielded consistent results. In the present study, 55 children and adolescents with temporal lobe epilepsy (TLE; 26 left, 29 right, 6-17 years) performed a verbal memory test before and 3 as well as 12 months after different types of temporal lobe resections (anterior lobectomy, amygdalo-hippocampectomy (AH), lesionectomy (LX)). Groups did not significantly differ before surgery. Three months after surgery, the left resected group showed a decline in learning and delayed recall, and performed significantly lower than the right resected group. Recoveries were evident 1 year after surgery. The postoperative memory declines were associated with a left-sided resection and a higher preoperative performance. Comparisons on the different resection types suggest a special risk in patients undergoing a left-sided AH. In summary, our results indicate a functional association of verbal memory functions with the left temporal lobe similar to findings in adult patients. Declines after left-sided temporal resections seem to be reversible at least for part of the children, perhaps due to the greater plasticity of the immature brain.

Adolescent↗

PubMed1989

[Thrombosed AVM presenting temporal lobe epilepsy].

A rare case of thrombosed AVM presenting temporal lobe epilepsy is reported. A 27-year old man was admitted to our hospital because of a 7-year history of temporal lobe epilepsy. He had also suffered from generalized seizure since he was 6 years old. No neurological deficit was disclosed. CT scan demonstrated a small calcified mass lesion in the left temporal lobe which was not enhanced by contrast study. Skull X - P and cerebral angiography were normal. Low intensity area on T1-weighted MR image corresponded to the high density area on CT scan. T2-weighted MR image demonstrated that peripheral low intensity area was more prominent and extensive. Conventional EEG showed focal spike discharges from the left fronto-central lead, and subdural EEG recordings showed intermittent spike discharges from the medial side of the left temporal lobe. A 5 cm temporal lobectomy was performed and a thick fibrous mass adjacent to the hippocampoamygdala complex was removed. Histopathological examination demonstrated a thrombosed AVM surrounded by gliotic neural tissue.

Adult↗

PubMed1994

Volumetric MRI assessment of temporal lobe structures in schizophrenia.

This magnetic resonance imaging (MRI) study was designed to investigate whether patients with schizophrenia have focal or lateralized deficits in the volumes of temporal lobe structures. Estimated volumes of the temporal lobes, hippocampi, superior temporal gyri, lateral ventricles, third ventricle, temporal horns of the lateral ventricles, and a frontal-parietal reference area (FPRA) were quantified for each hemisphere. The schizophrenic group had less gray matter (GM) in the temporal lobes and the FPRA relative to controls. Ventricular volumes were significantly larger in the schizophrenic group, as was cerebrospinal fluid (CSF) volume for temporal lobe sulci. No significant differences in hippocampal volumes emerged between groups. The magnitude of GM deficit was not greater in the temporal lobes relative to the FPRA. These results confirm the presence of bilateral GM volume deficits of the temporal lobes in schizophrenia but do not support the hypothesis that structural changes preferentially affect the temporal lobes or the left cerebral hemisphere.

Adult↗

PubMed1998

Reduction in temporal N-acetylaspartate and creatine (or choline) ratio in temporal lobe epilepsy: does this 1H-magnetic resonance spectroscopy finding mean poor seizure control?

BACKGROUND: Proton magnetic resonance spectroscopy (1H-MRS) is a potentially useful tool in the in vivo investigation of brain metabolites in intractable temporal lobe epilepsy (TLE). Focal N-acetylaspartate (NAA) reductions have been correlated with mesial temporal sclerosis (MTS) in surgically resected epileptogenic foci. OBJECTIVE: To evaluate the abnormalities in the metabolites NAA, creatine+ phosphocreatine (Cr), and choline containing compounds (Cho) in the temporal lobe of medically refractory patients with temporal lobe epilepsy, seizure free patients with temporal lobe epilepsy, and normal controls. PATIENTS AND METHODS: Ten refractory patients, 12 seizure free patients with temporal lobe epilepsy, and 10 age matched normal controls were studied by 1H-magnetic resonance spectroscopy. All patients had consistently unilateral temporal EEG abnormalities and a normal brain MRI. Proton MR spectra were obtained from an 8 ml volume in the medial temporal lobes in patients with temporal lobe epilepsy (ipsilateral to EEG foci) and the normal controls. The signals measured were expressed in terms of NAA/Cr, NAA/Cho, and Cho/Cr. RESULTS: When compared with seizure free patients with temporal lobe epilepsy and normal controls, the 10 refractory patients with temporal lobe epilepsy had a lower mean (SEM) NAA/Cr ratio (1.65 (0.53) v 2.62 (0.60), and 2.66 (0.73); p<0.002 and p<0.006) and a lower mean NAA/Cho ratio (1.59 (0.79) v 2.83 (1.33) and 2.58 (0.67); p<0.02 and p<0.007). Furthermore, the two patients showing the lowest NAA/Cr ratios (1.47 and 1.73) in the seizure free group had had a past period of poor seizure control. CONCLUSIONS: There were reduced temporal NAA/Cr and NAA/Cho ratios, suggesting neuronal loss or damage, associated with past or present poor seizure control in the patients with temporal lobe epilepsy, but it does not exclude the possibility of a future complete seizure control (seizure free patients with temporal lobe epilepsy at the time of 1H-MRS). This study warrants further 1H-MRS investigation with a larger series of patients with temporal lobe epilepsy.

Adolescent↗

PubMed1994

Schizophrenia and temporal lobe epilepsy. A neuropsychological analysis.

BACKGROUND: Recent neuroimaging studies have reported structural abnormalities of mesial temporal lobe structures in schizophrenia. This study compared the neuropsychological performance of patients with schizophrenia with patients with either left or right temporal lobe epilepsy to determine if lateralized, developmental temporal lobe dysfunction provides a model of the cognitive impairments observed in schizophrenia. METHODS: A total 66 patients with schizophrenia and 101 patients with medically intractable focal temporal lobe epilepsy (48 left temporal, 53 right temporal) received a comprehensive neuropsychological battery. RESULTS: The three groups did not differ on age, years of education, or Full-Scale IQ. However, clear differences were noted in performance profiles. Patients with schizophrenia scored significantly higher than either epilepsy group on a measure of word reading thought to reflect premorbid competence. Patients with schizophrenia demonstrated greater attentional impairment and motor slowing than either epilepsy group. The patients with schizophrenia had superior semantic knowledge and verbal memory compared with the left temporal lobe group. On the Wisconsin Card Sorting Test the patients with schizophrenia obtained significantly fewer categories than either temporal lobe group, but were not significantly more perseverative. CONCLUSIONS: Data suggest lateralized temporal lobe dysfunction does not provide an adequate model of the cognitive impairments seen in schizophrenia. The disorders seem to follow different developmental paths: In early-onset epilepsy, the acquisition of cognitive skills and academic knowledge is compromised, while in schizophrenia cognitive functions are lost. Extratemporal pathologic features, most likely of the frontal lobe, are implicated in the cognitive dysfunction of schizophrenia.

Adult↗

PubMed1998

Characteristics and treatment of temporal lobe epilepsy with a history of complicated febrile convulsion.

This study aimed to examine the close correlation between complicated febrile convulsions (CFC) and medial temporal lobe epilepsy and to delineate characteristics of temporal lobe epilepsy with CFC. Patients with temporal lobe epilepsy were divided into those with a prior episode of CFC (n=52), those with febrile convulsions other than CFC, and those without either (n=345). Clinical constellations, neuroimaging, drug resistance, and effects of temporal lobectomy of the three groups were compared. A close association between CFC and temporal lobe epilepsy was confirmed. The salient features of temporal lobe epilepsy with CFC were early age at onset of habitual seizures (about 10 years), the predominance of autonomic auras, and a high incidence of MRI evidence of unilateral medial temporal sclerosis. Patients with temporal lobe epilepsy with prior CFC had an excellent outcome after surgery, by contrast with an unfavourable response to drug therapy. The surgical results were discouraging in patients with temporal lobe epilepsy without history of any febrile convulsions and without solid brain tumours. These results indicate surgical intervention as the choice of therapy in a substantial number of patients with temporal lobe epilepsy with a history of CFC.

Adult↗

PubMed1999

A comparison of egocentric and allocentric spatial memory in medial temporal lobe and Korsakoff amnesics.

Two patients with medial temporal lobe damage, seven Korsakoff amnesics and fourteen healthy control subjects were tested on three conditions of a spatial memory test ('short delay', 'allocentric' and 'egocentric'). The task required subjects to recall the position of a single spot of light presented on a board after various delays. The 'short delay' condition tested memory over very short, unfilled intervals. The other two conditions used longer, filled delays. The allocentric condition required subjects to move to a different place around the board before recalling the position of the light. In the egocentric condition stimuli were presented in darkness, which eliminated allocentric cues. The Korsakoff amnesics were impaired at all delays of the short delay tasks, suggesting poor encoding. On the allocentric and egocentric tasks the Korsakoff amnesics showed a comparable impairment in the two conditions, which worsened with delay. This accelerated forgetting suggested that the Korsakoff amnesics also had impaired memory for allocentric and egocentric information. The patients with medial temporal lobe damage were unimpaired in the 'short delay' condition suggesting intact encoding and short-term memory of spatial information. However, they were impaired in the allocentric condition and showed accelerated loss of allocentric spatial information. In the egocentric condition, while the performance of one patient was impaired, the performance of the other was as good as controls. This result suggests that, in contrast to allocentric spatial memory, which is sensitive to medial temporal lobe damage, an intact medial temporal lobe need not be necessary for successful performance on an egocentric spatial memory task.

Aged↗

PubMed1994

Contribution of the right temporal lobe to musical timbre discrimination.

Patients with unilateral temporal lobe excisions and normal control subjects were tested in timbre discrimination tasks in which the stimuli differed by either the number of harmonics (a spectral cue) or by the duration of the rise and fall times (a time cue). Patients with right temporal lobe lesions exhibited a significant deficit in discriminating both spectral and time information, in comparison to patients with left temporal lobe lesions and normal control subjects. This finding suggests that musical timbre perception, examined in a psychoacoustic sense, depends on neural systems found within the right temporal lobe.

Acoustic Stimulation↗

PubMed2001

Diagnosis and surgical treatment of temporal lobe epilepsy.

OBJECTIVE: To discuss the diagnosis and surgical treatment of temporal lobe epilepsy. METHODS: From 1996 to 1998, 36 patients presenting with medically intractable temporal lobe epilepsy were identified by EEG and MR, including volumetric MR, for hippocampal formation. Among them, 16 patients underwent anterior temporal lobectomy, while 20 patients accepted selective amygdalohippocampectomy. The results of surgical operation and follow-up are analyzed. RESULTS: With respect to seizure outcome, all patients benefited from surgery. The surgical results were satisfactory in 24 cases, notable in 11 cases, and good in 1 case, and there were no complications. CONCLUSION: MR is beneficial for the localization of epileptic foci. Surgery is an effective method for the treatment of temporal lobe epilepsy; selective amygdalohippocampectomy is the first choice for medial temporal lobe epilepsy. The transzygmatic-temporal lobe base approach presented in this study improved the safety of the surgery.

Adolescent↗

PubMed2005

Cerebral perfusion changes in mesial temporal lobe epilepsy: SPM analysis of ictal and interictal SPECT.

We examined cerebral perfusion changes in mesial temporal lobe epilepsy (mTLE) by the statistical parametric mapping of brain single photon emission computed tomography (SPECT) images of 38 mTLE patients and 19 normal controls. Ictal and interictal SPECTs were compared with control SPECTs by independent t test, and ictal and interictal SPECTs by paired t test. We evaluated the number of heterotopic neurons in temporal lobe white matter, white matter changes of the anterior temporal lobe (WCAT) and ictal hyperperfusion of the temporal stem (IHTS). Left mTLE showed interictal hypoperfusion in the ipsilateral hippocampus, bilateral thalami, and paracentral lobules. Right mTLE showed hypoperfusion in bilateral hippocampi, contralateral insula, bilateral thalami, and paracentral lobules. Both mTLEs showed ictal hyperperfusion in bilateral temporal lobes with ipsilateral predominance, and in the anterior frontal white matter bilaterally. By paired t test, ictal hyperperfusion was found in the ipsilateral temporal lobe, temporal stem, hippocampus, thalamus, putamen, insula, and bilateral precentral gyri, whereas ictal hypoperfusion was found in bilateral frontal poles and middle frontal gyri. Fifteen patients showed WCAT and 19 showed IHTS, a weak correlation was observed between WCAT and IHTS (r = 0.377, P = 0.02). WCAT was found to correlate with an early seizure onset age. In 35 patients, heterotopic neurons were found in the white matter of the resected temporal lobe, but the number of heterotopic neurons did not correlate with WCAT or IHTS. In summary, the cerebral perfusion patterns of mTLE suggest interictal hypofunction and ictal activation of the cortico-thalamo-hippocampal-insular network and ictal hypoperfusion of the anterior frontal cortex.

Adolescent↗

PubMed2001

Magnetic resonance spectroscopy and histopathological findings in temporal lobe epilepsy.

PURPOSE: In some patients with temporal lobe epilepsy, histopathological evaluation of resected brain tissue after surgical treatment may reveal several features indicative of discrete cortical malformations. We sought to determine whether these histopathological features were accompanied by hippocampal changes detectable preoperatively by proton magnetic resonance (MR) spectroscopy and to evaluate their relationship with postoperative outcome. METHODS: In 25 consecutive temporal lobe epilepsy patients who were scheduled for surgical treatment, MR spectroscopy was performed, and resected brain tissue was analyzed histopathologically for the presence of discrete cortical malformations (e.g., microdysgenesis). Outcome was assessed in all patients with an average postoperative period of 26 months. RESULTS: In 13 patients, we found subtle, histopathologically detectable signs of cortical malformation: 6 of them with concomitant hippocampal sclerosis (dual pathology) and 7 without. The latter subgroup had a worse surgical outcome and showed enhanced bilateral and/or contralateral pathological changes in the hippocampal formation when investigated by MR spectroscopy. CONCLUSIONS: These data suggest that by showing contralaterally or bilaterally abnormal spectra, MR spectroscopy might be able to indicate pathological changes in subtle developmental disorders that are possibly more widespread over the brain. This observation may improve noninvasive diagnosis in presurgical evaluation and the neurobiological understanding of cortical malformations in pharmacoresistant temporal lobe epilepsy.

Adult↗

PubMed1982

Sequential EEG findings and symptoms in partial seizures of temporal lobe origin.

45 cases of partial seizures of temporal lobe origin undergoing sequential EEG investigation first with routine and then methohexitone activated EEG, 31 supplemented by sphenoidal electrodes, are reported. Methohexitone activated foci from temporal lobes which had previously not displayed temporal spike or sharp wave discharges in 15 (33.3%) cases. In 11 (24.4%) this was the first evidence of the focus in 15 (33.3%) cases. In 11 (24.8%) this was the first evidence of the focus in either temporal lobe and in 4 (8.9%) the focus was contralateral to one already seen in routine EEG. In 3 (6.7%) cases the sphenoidal electrodes were essential for demonstrating the focus. Methohexitone evoked temporal spikes or sharp waves irrespective of the nature of the initial routine EEG which was either normal, had non "epileptic" temporal abnormalities or abnormalities outside the temporal region. 2 X 2 chi 2 tests, comparing the frequency with which a particular symptom was accompanied by an EEG in a sequence with temporal discharges, showed that only in the case of evolution to generalised tonic/clonic seizures (secondary generalization) was the association statistically significant: chi 2 4.28, P less than 0.025. Similar testing of length of history and frequency of attacks against the frequency with which temporal discharges occurred failed to establish a statistically significant association.

Adolescent↗

PubMed2001

In vivo short echo time 1H-magnetic resonance spectroscopic imaging (MRSI) of the temporal lobes.

Two different methodologies for obtaining PRESS-localized magnetic resonance spectroscopic imaging (MRSI) data from the mesial and lateral temporal lobes were investigated. The study used short echo times (30 ms) and long repetition times (3000 ms) to minimize relaxation effects. Inhomogeneity and spectral distortions from the proximity of the temporal bones precluded the attainment of consistently good-quality data from both temporal lobes at once. Even when the right and left temporal lobes were studied separately, distortions often disturbed spectra from the anterior lateral temporal lobe. Quantitative analysis using LCModel was therefore performed only on the posterior lateral temporal lobe, and the posterior, middle, and anterior mesial temporal lobe. No significant left-right differences in metabolite content were found in a series of 10 controls. Significantly higher concentrations of myoinositol and choline were found in the anterior mesial temporal lobe, even when grey matter content was included as a covariate. The concentration of N-acetyl aspartate plus N-acetyl aspartyl glutamate (NAc) was not found to vary significantly along the length of the hippocampus. The previously observed lower anterior ratios of NAA to creatine plus choline (NAA/(Cr + Cho) may instead have been due to higher anterior choline. Large differences in metabolite concentrations were seen between posterior lateral temporal lobe (predominantly subcortical white matter) and the posterior mesial temporal lobe, most notably lower creatine, glutamate/glutamine, and myo-inositol, and higher NAA/(Cr + Cho) in the lateral than mesial temporal lobe. This pattern was similar to that previously seen for grey/white matter differences in the frontal, parietal and occipital regions.

Adult↗

PubMed1998

Short-term and long-term memory in early temporal lobe dysfunction.

Following medial temporal damage, mature humans are impaired in retaining new information over long delays but not short delays. The question of whether a similar dissociation occurs in children was addressed by testing children (ages 7-16) with unilateral temporal lobe epilepsy (TLE) and controls on short- and long-term memory tasks, including a spatial delayed response task (SDR). Early-onset TLE did not affect performance on short delays on SDR, but it did impair performance at the longest delay (60 s), similar to adults with unilateral medial temporal damage. In addition, early-onset TLE affected performance on pattern recall, spatial span, and verbal span with rehearsal interference. No differences were found on story recall or on a response inhibition task.

Age of Onset↗