Spike frequency is dependent on epilepsy duration and seizure frequency in temporal lobe epilepsy.

OBJECTIVES: We wanted to investigate factors that are associated with frequency of interictal epileptiform discharges by investigating 303 patients with temporal lobe epilepsy (TLE). METHODS: We included all patients who consecutively underwent the adult presurgical evaluation program at our center and who had intractable, medial TLE with complex partial seizures due to unilateral medial temporal lobe lesions. The interictal EEG samples were automatically recorded and stored on computer. The location and frequency of interictal epileptiform discharges were assessed by visual analysis of interictal EEG samples of 2-minute duration every hour. RESULTS: There were 303 patients (aged 16-63) who met the inclusion criteria. The median interictal epileptiform discharge frequency was 15 IED/h, the median seizure frequency was 4 seizures/month. According to univariate analyses, we found that age at monitoring, epilepsy duration, and higher seizure frequency were associated with higher interictal epileptiform discharge frequency. In the logistic regression analysis, we found that higher seizure frequency (p < 0.001) and longer epilepsy duration (p = 0.007) were independently associated with higher spike frequency, while the age at monitoring was not. CONCLUSIONS: Seizure frequency and epilepsy duration (years of patient's life with seizure activity) were independently associated with IED frequency, suggesting that IED are modulated by seizures.     

Comparison of electroencephalographic dipoles of interictal spikes from prolonged scalp video-electroencephalography and magnetoencephalographic dipoles from short-term recording in children with extratemporal lobe epilepsy

We retrospectively compared electroencephalographic (EEG) dipoles of interictal spikes from prolonged video-EEG monitoring with magnetoencephalographic dipoles from short-term recording in four children with extratemporal lobe epilepsy. We analyzed both sets of dipoles using individual interictal spikes and single moving dipole modeling and evaluated the profiles of spike appearance, dipole position, and orientation in EEG and magnetoencephalography. We obtained more than 100 magnetoencephalographic spikes in two patients who manifested frequent interictal EEG spikes throughout both day and night but fewer than 40 magnetoencephalographic spikes in two patients who had interictal EEG spikes mainly during sleep. The dipole positions of EEG and magnetoencephalography were in close proximity and included in the surgical resection area. Most of the dipoles between EEG and magnetoencephalography were oriented perpendicularly. A combination of EEG dipole analysis from prolonged video-EEG monitoring and magnetoencephalographic dipole analysis provides complementary information for presurgical evaluation in children with intractable extratemporal lobe epilepsy.     

Is interictal EEG activity a biomarker for mood disorders in temporal lobe epilepsy?

Objective

Psychiatric comorbidities are frequent in temporal lobe epilepsy (TLE), and symptoms of these comorbidities may be related to epilepsy activity. Here we evaluated interictal EEG activity in TLE patients with or without psychiatric comorbidities.

Methods

A cohort study of 78 patients with TLE, with evaluation of wake/sleep interictal scalp EEG. All subjects were submitted to a psychiatric structured clinical interview (SCID) for the diagnosis of lifetime psychiatric comorbidities. Three major diagnostic categories were studied: mood disorders, anxiety disorders, and psychosis. We then evaluated differences in interictal EEG activity between patients with and without these psychiatric comorbidities.

Results

Infrequent EEG interictal spikes, defined as less than one event per minute, were significantly associated with mood disorders in TLE (p = 0.02).

Conclusions

Low intensity seizure disorder has been associated with a decrease in interictal EEG discharges and with an increase in psychiatric symptoms in TLE, a phenomenon known as forced normalization. In our study, we observed a low interictal spike frequency on EEG in TLE patients with mood disorders.

Significance

A low spike index might be a neurophysiological marker for depression in temporal lobe epilepsy.     

Prognostic factors in the surgical treatment of medically intractable epilepsy associated with mesial temporal sclerosis

OBJECTIVES: To assess the prognostic factors determining seizure remission after temporal lobectomy for intractable epilepsy associated with mesial temporal sclerosis (MTS) at pathology. METHODS: The clinical and investigative features of 116 consecutive patients who had temporal lobe surgery for drug-resistant epilepsy and MTS at pathology were assessed using actuarial statistics and logistic regression analysis. RESULTS: At a median follow-up of 63 months the probability of achieving at least a 1-year period of continuous seizure freedom was 67%. Factors contributing to a favourable outcome were interictal EEG localization to the operated lobe and the absence of secondarily generalized seizures. These were also selected in the multivariate analysis, although at lower statistical significance (P=0.08 and 0.09, respectively). Perinatal complications were associated with a significantly worse outcome but overall, complicated febrile convulsions and congruent neuropsychological deficits were not significantly predictive variables. CONCLUSIONS: The present findings may aid in the non-invasive presurgical assessment of patients with intractable TLE and clinical and neuroimaging evidence of MTS.     

Clinical Usefulness of the Dipole Tracing Method for Localizing Interictal Spikes in Partial Epilepsy

Summary: Purpose: To clarify the clinical usefulness of the dipole tracing method in evaluation of interictal EEG spikes in patients with partial epilepsy.
Methods : Eight patients with partial epilepsy were studied. We compared the generator source of interictal spikes detected by the dipole tracing method with the results of magnetic resonance imaging (MRI), interictayictal measurement of cerebral blood flow (CBF) by single photon emission computed tomography (SPECT), interictal measurement of glucose metabolism by positron emission tomography (PET) and invasive electrocorticogram (ECoG).
Results : In 5 patients with mesial temporal lobe epilepsy (TLE), including 3 patients who underwent standard temporal lobectomy, the dipole tracing method showed results consistent with those of other examinations and better correlation with ECoG than with other noninvasive examinations. In a patient with mesial TLE who had defects in the skull due to previous surgery, the dipoles were located more laterally than expected. In a patient with frontal lobe epilepsy (FLE) who was finally proved to have an epileptogenic area in the lateral frontal area, the spike dipoles were identified in the medial side of the frontal lobe.
Conclusions : The dipole tracing method used in the present study is useful for localizing epileptogenic areas in patients with mesial TLE. However, in patients with partial skull defects and in those with FLE, the reliability of this method is still in accuracy of the lobe level.     

Interictal regional delta slowing is an EEG marker of epileptic network in temporal lobe epilepsy

Purpose: Several studies have suggested that interictal regional delta slowing (IRDS) carries a lateralizing and localizing value similar to interictal spikes and is associated with favorable surgical outcomes in patients with temporal lobe epilepsy (TLE). However, whether IRDS reflects structural dysfunction or underlying epileptic activity remains controversial. The objective of this study is to determine the cortical electroencephalography (EEG) correlates of scalp‐recorded IRDS, in so doing, to further understand its clinical and biologic significances. Methods: We examined the cortical EEG substrates of IRDS with electrocorticography (ECoG‐IRDS) and delineated the spatiotemporal relationship between ECoG‐IRDS and both interictal and ictal discharges by recording simultaneously scalp and intracranial EEG in 18 presurgical candidates with TLE. Key Findings: Our results demonstrated that ECoG‐IRDS is typically a mixture of delta/theta slowing and spike‐wave potentials. ECoG‐IRDS was predominantly recorded from basal and anterolateral temporal cortex, occasionally in mesial, posterior temporal, and extratemporal regions. Abundant IRDS was most commonly observed in patients with neocortical temporal lobe epilepsy (NTLE), whereas infrequent to moderate IRDS was usually observed in patients with mesial temporal lobe epilepsy (MTLE). The anatomic distribution of ECoG‐IRDS was highly correlated with the irritative and seizure‐onset zones in 10 patients with NTLE. However, it was poorly correlated with the irritative and seizure‐onset zones in the 8 patients with MTLE. Significance: These findings demonstrate that IRDS is an EEG marker of epileptic network in patients with TLE. Although IRDS and interictal/ictal discharges likely arise from the same neocortical generator in patients with NTLE, IRDS in patients with MTLE may reflect a network disease that involves temporal neocortex.     

Presurgical electroencephalographic patterns and outcome from anterior temporal lobectomy.

We reviewed data from 48 patients after anterior temporal lobe resection for medically intractable epilepsy. All had ictal electro-encephalographic (EEG) evidence of unilateral temporal lobe onset. Depth electrodes were used in 19 patients. Successful surgical outcome correlated significantly with factors that suggested a temporal lobe focus, particularly in the interictal scalp EEG. The most successful outcome occurred in patients with well-localized unilateral interictal temporal spikes (100% improved). The group with well-localized bilateral temporal spikes also did well (76% improved). Patients with extratemporal spread of the interictal spike on scalp EEG, either unilaterally or bilaterally, did less well. Only one third improved, despite extensive extracranial and intracranial monitoring, when indicated. The interictal scalp EEG may be the only EEG necessary for the presurgical evaluation of selected patients with intractable temporal lobe epilepsy.     

Cortical current density reconstruction of interictal epileptiform activity in temporal lobe epilepsy.

OBJECTIVE: To investigate the value of cortical current density (CCD) reconstruction in localizing intracranial generators of interictal epileptiform activity in mesial and lateral temporal lobe epilepsy (TLE). METHODS: Non-linear minimum L(1)-norm CCD reconstruction (with current sources restricted to the individual cortical surface and a realistic boundary element method (BEM) head model) was used to localize and to study the propagation of interictal epileptiform EEG activity in 13 pre-surgical patients with TLE. RESULTS: In all but one patient with mesial temporal lesions, an initial activation maximum corresponding to the ascending part of averaged sharp waves was found in the ipsilateral anterior basolateral temporal lobe, mostly extending up to the affected mesial structures whose resection rendered the patients seizure-free. In all 3 patients with lateral temporal lesions, the activation was initially confined to temporal neocortex immediately adjacent to the epileptogenic lesion. Towards the peak of sharp waves, two patients showed a propagation of interictal activity to anterior and posterior and partly contralateral temporal regions. A conventional EEG analysis based on amplitude maxima or phase reversal would have missed the initial onset zone. CONCLUSIONS: The findings demonstrate that CCD reconstruction can be a valuable additional non-invasive component in the multimodal pre-surgical evaluation of epilepsy patients.     

Spatiotemporal relationship between seizure activity and interictal spikes in temporal lobe epilepsy.

PURPOSE: To analyze the spatio-temporal relationship between seizure propagation and interictal epileptiform discharges (IEDs) in patients with bitemporal epilepsy. METHODS: We investigated 18 adult patients with intractable temporal lobe epilepsy (TLE) who had undergone continuous video-EEG monitoring during presurgical evaluation. Only those patients were selected who had independent IEDs over both temporal lobes. Two authors evaluated the ictal and interictal EEG data independently. RESULTS: We analyzed 52 lateralized seizures of 18 patients. Thirty-one seizures showed ipsilateral seizure spread exclusively, whereas in 21 seizures the contralateral hemisphere was also involved. In lateralized seizures without contralateral propagation, we found that spikes ipsilateral to the seizure onset occurred postictally in a greater ratio than preictally (P<0.001). In lateralized seizures with contralateral propagation, we found no significant changes in the postictal spike distribution. CONCLUSIONS: Our findings showed that the lateralization of IEDs may depend on the brain areas involved by the preceding seizures, suggesting that spikes can be influenced by the seizure activity, and are not independent signs of epileptogenicity.     

Interictal and postictal language testing accurately lateralizes language dominant temporal lobe complex partial seizures

PURPOSE: Noninvasive tests that accurately localize seizure onset provide great value in the presurgical evaluation of patients with intractable epilepsy. This study examined the diagnostic utility of three expressive language disturbances in lateralizing language-dominant (DOM) temporal lobe complex partial seizures: (1) the postictal language delay (PILD; time taken to correctly read a test phrase out loud immediately following seizures); (2) the production of postictal phonemic paraphasic errors (PostPE); and (3) interictal phonemic paraphasic errors (InterPE). METHODS: All 60 subjects underwent inpatient video/EEG monitoring and had surgically confirmed temporal lobe epilepsy (TLE). We determined the presence and number of PostPE and, PILD times (in s) for 212 seizures, and InterPE on the Boston Naming Test (BNT). Each technique's diagnostic usefulness was evaluated via logistic regression and ROC curve analysis. Sensitivity, specificity, positive predictive value and negative predictive values were computed. RESULTS: PILD, PostPE and InterPE production were equally effective and accurate in lateralizing DOM seizure onset. Patients with DOM TLE had a longer PILD and committed more PostPE and InterPE than those with nondominant (NDOM) TLE. Respective sensitivity and specificity values were as follows: PILD (84%, 86%), PostPE (94%, 64%), and InterPE (97%, 86%). No single predictor was significantly better but a combination model yielded enough incremental utility to collectively outperform each separate predictor model. CONCLUSIONS: Interictal language testing is as accurate as postictal language testing in predicting DOM lateralization of TLE. Clinicians should also attend to the quality of errors produced during interictal and postictal language testing.     

Temporal lobe interictal epileptic discharges affect cerebral activity in "default mode" brain regions

A cerebral network comprising precuneus, medial frontal, and temporoparietal cortices is less active both during goal-directed behavior and states of reduced consciousness than during conscious rest. We tested the hypothesis that the interictal epileptic discharges affect activity in these brain regions in patients with temporal lobe epilepsy who have complex partial seizures. At the group level, using electroencephalography-correlated functional magnetic resonance imaging in 19 consecutive patients with focal epilepsy, we found common decreases of resting state activity in 9 patients with temporal lobe epilepsy (TLE) but not in 10 patients with extra-TLE. We infer that the functional consequences of TLE interictal epileptic discharges are different from those in extra-TLE and affect ongoing brain function. Activity increases were detected in the ipsilateral hippocampus in patients with TLE, and in subthalamic, bilateral superior temporal and medial frontal brain regions in patients with extra-TLE, possibly indicating effects of different interictal epileptic discharge propagation.     

Chronic temporal lobe epilepsy: spatial extent and degree of metabolic dysfunction studied with magnetic resonance spectroscopy (MRS)

INTRODUCTION: Proton magnetic resonance spectroscopy ((1)H MRS) has been proposed as a lateralizing method for the presurgical evaluation of patients with medically intractable temporal lobe epilepsy (TLE). Studies have shown correlations between temporal lobe (TL) NAA and seizure frequency, and TL NAA/Cr and the duration of epilepsy in patients with TLE. This latter finding may suggest that progressive neuronal dysfunction may occur in both temporal lobes in patients with TLE, even when the seizures originate in only one temporal lobe. We analyzed our data in an attempt to find a possible correlation between extension of neuronal dysfunction based on NAA measures and duration of epilepsy. METHODS: We studied 45 consecutive patients with the diagnosis of TLE, who were referred for presurgical evaluation. Duration of epilepsy was defined as the interval between the age of seizure onset and the time of the MRS examination. All studies were performed in the inter-ictal state, prior to intracranial monitoring or resection. We performed two-tailed Pearson correlation analysis between ipsilateral NAA/Cr and extension of the abnormality (voxels involved) and the duration of the seizure disorder in years. RESULTS: The average duration of epilepsy in this group was 20 years. No significant correlation was found between duration of epilepsy and mean hippocampal NAA/Cr (r=-.131, p=.390); nor was a correlation found between duration of epilepsy in years or the extent of metabolic lesion (voxels involved) (r=-.264, p=.079). CONCLUSIONS: Hippocampal NAA/Cr does not correlate with duration of epilepsy in TLE. Our findings suggest that cross-sectional group measures of hippocampal neuronal function do not suggest damage progression.     

Temporal lobe epilepsy with sensory aura: interictal glucose hypometabolism

Patients with mesial temporal lobe epilepsy (mTLE) exhibit marked depressions of the regional cerebral glucose metabolism (rCMRGlu) in the mesiotemporal region. We hypothesised that patients with temporal lobe epilepsy (TLE) who have a bilateral somatosensory or acoustic ( = temporolateral/SII-) aura can be differentiated from mTLE by rCMRGlu depressions primarily involving temporo-perisylvian locations. We therefore used this ictal semiology as a clinical criterion to define a subgroup of such patients and measured the rCMRGlu in 16 patients with TLE as evident from interictal and ictal EEG-video monitoring. Clinically, they presented with medically refractory complex partial seizures and were subjected to presurgical evaluation. The pattern of the interictal rCMRGlu in the TLE patients was different from that observed in patients with mTLE and showed significant depressions ipsilateral to the epileptic focus in mesial temporal and lateral temporal regions but spared the thalamus. The neocortical metabolic depressions were spatially more extended in right than in left TLE patients. Magnetic resonance images (MRI) were either normal (n = 5) or revealed unilateral or bilateral hippocampal atrophy/sclerosis (n = 7), or temporal or extratemporal focal cortical dysplasia (n = 4). The selected TLE patients presented here comprise a heterogeneous group showing most pronounced metabolic depressions in the lateral temporal cortex. Thus, our data suggest that non-invasive metabolic imaging can assist in identifying the neocortical symptomatogenic zone in putative temporo-perisylvian lobe epilepsy.     

EEG background delta activity in temporal lobe epilepsy: correlation with volumetric and spectroscopic imaging

PURPOSE: With quantitative electroencephalogram (EEG) and neuroimaging methods, we examined delta activity, atrophy, and neuronal-axonal dysfunction of the cerebral gray and white matter in patients with intractable temporal lobe epilepsy (TLE). Based on evidence that lesions of the white matter result in EEG delta activity, we postulated that background abnormalities in patients with TLE are related to changes of the temporal lobe white matter. METHODS: We measured interictal delta activity in 34 TLE patients and 10 controls. Spike-free and artifact-free EEG samples were selected by visual inspection. A spectral analysis was used to compute the energy in the delta frequency band. We compared the results of the spectral analysis to magnetic resonance imaging- (MRI) based volumes of the temporal lobe white and gray matter, the hippocampus and the amygdala; and N-acetyl aspartate (NAA) in the lateral and posterior temporal lobe by using proton magnetic resonance spectroscopic imaging (1H-MRSI). The degree of correlation between delta activity and the neuroimaging measurements was assessed by using the Pearson correlation coefficient (r). An analysis of variance (ANOVA) was used to examine the influence of the seizure-focus lateralization on the delta activity and the neuroimaging parameters. RESULTS: There was no significant difference in the amount of delta activity in the temporal lobe between the controls and patients. We found no correlation between delta activity and the neuroimaging measures (p>0.05). The ANOVA showed significant differences between the patients and controls for the volume of the gray and white matter of the temporal lobe and for the NAA in the lateral and posterior temporal lobe (p<0.002). CONCLUSIONS: The interictal background delta activity was not explained by reduced volume of the temporal lobe white matter, gray matter, or by abnormalities seen in 1H-MRSI.     

Neuronal Complexity Loss in Interictal EEG Recorded with Foramen Ovale Electrodes Predicts Side of Primary Epileptogenic Area in Temporal Lobe Epilepsy: A Replication Study

Summary: Purpose: To investigate whether a correct lateralization of the primary epileptogenic area by means of neuronal complexity loss analysis can be obtained from interictal EEG recordings using semi-invasive foramen ovale electrodes. In a previous study with recordings from intrahippocampal depth and subdural strip electrodes it was shown that the dynamics of the primary epileptogenic area can be characterized by an increased loss of neuronal complexity in patients with unilateral temporal lobe epilepsy (TLE).
Methods: Neuronal complexity loss analysis was applied. This analysis method is derived from the theory of nonlinear dynamics and provides a topological diagnosis even in cases where no actual seizure activity can be recorded. We examined interictal EEG recorded intracranially from multipolar foramen ovale electrodes in 19 patients with unilateral TLE undergoing presurgical evaluation.
Results: The primary epileptogenic area was correctly lateralized in 16 of the 19 investigated patients. The misclassification of the side of seizure onset in three patients might be attributed to the larger distance between the foramen ovale electrodes and the mesial temporal structures as compared to intrahippocampal depth electrodes.
Conclusions: Our results confirm the previous findings and provide further evidence for the usefulness of nonlinear time-series analysis for the characterization of the spatiotemporal dynamics of the primary epileptogenic area in mesial temporal lobe epilepsy.     

Neuromagnetic recordings in temporal lobe epilepsy.

The introduction of whole-head magnetoencephalography (MEG) systems facilitating simultaneous recording from the entire brain surface has established MEG as a clinically feasible method for the evaluation of patients with temporal lobe epilepsy (TLE). In mesial TLE, two types of MEG spike dipoles could be identified: an anterior vertical and an anterior horizontal dipole. Dipole orientations can be used to attribute spike activity to temporal lobe subcompartments. Whereas the anterior vertical dipole is compatible with epileptic activity in the mediobasal temporal lobe, the anterior horizontal dipole can be explained by epileptic activity of the temporal tip cortex. In nonlesional TLE, medial and lateral vertical dipoles were found which could distinguish between medial and lateral temporal seizure onset zones as evidenced from invasive recordings. In lesional TLE, MEG could clarify the spatial relationship of the structural lesion to the irritative zone. Evaluation of patients with persistent seizures after epilepsy surgery may represent another clinical important application of MEG because magnetic fields are less influenced than electric fields by the prior operation. Simultaneous MEG and invasive EEG recordings indicate that epileptic activity restricted to mesial temporal structures cannot reliably be detected on MEG and that an extended cortical area of at least 6 to 8 cm2 involving also the basal temporal lobe is necessary to produce a reproducible MEG signal. In lateral neocortical TLE MEG seems to be more sensitive than scalp-EEG which further underlines the potential role of MEG for the study of nonlesional TLE. Whole-head MEG therefore can be regarded as a valuable and clinically relevant noninvasive method for the evaluation of patients with TLE.     

Contralateral temporal hypometabolism on positron emission tomography in temporal lobe epilepsy

Introduction — No detailed case studies report lateralised hypometabolism on positron emission tomography (PET) contralateral to the epileptogenic focus in temporal lobe epilepsy (TLE). Material and methods — We performed ¹⁸F fluorodeoxyglucose (FDG) PET in two intractable TLE patients. Results — One had right temporal interictal spikes on electroencephalography (EEG) and a right medial temporal lobe lesion on magnetic resonance imaging (MRI). FDG-PET showed decreased uptake in the left temporal lobe. Right temporal ictal onset, with bilateral interictal epileptiform activity, occurred on intracranial EEG. He is seizure free after right temporal lobectomy and ganglioglioma resection. The second had right temporal lobe interictal and ictal EEG activity. MRI demonstrated right anteriomedial temporal increased T2 signal. Neuropsychology revealed bilateral cognitive dysfunction. FDG-PET showed left anterior temporal and lateral frontal hypometabolism. He is seizure free after right temporal lobectomy. Conclusion — These findings suggest that regional uptake asymmetry on FDG-PET may be give misleading lateralising information in TLE.     

Lack of aura experience correlates with bitemporal dysfunction in mesial temporal lobe epilepsy

The diagnostic value of lack of aura experience in patients with temporal lobe epilepsy (TLE) is unclear. PURPOSE: To evaluate possible factors of bitemporal dysfunction in patients with mesial TLE who did not experience an aura in electroencephalography EEG/video monitoring for epilepsy surgery. METHODS: Ictal scalp EEG propagation patterns of 347 seizures of 58 patients with mesial temporal lobe sclerosis or non-lesional mesial TLE, interictal epileptiform discharges (IED), presence of unilateral mesial temporal lobe sclerosis in visual magnetic resonance imaging (MRI) analysis, prose memory performance, history or not of an aura, and postictal memory or absence of an aura were analyzed. The ictal EEG was categorized as follows. EEG seizure: (a) remaining regionalized, (b) non-lateralized, (c) showing later switch of lateralization or bitemporal asynchronous ictal patterns. RESULTS: Absent aura in monitoring was significantly correlated with absence of unitemporal MRI sclerosis (P=0.004), bitemporal IED (P=0.008), and propagation of the ictal EEG to the contralateral temporal lobe (P=0.001). Other historical data and interictal prose memory performance were not significantly correlated with absent aura. Ten of 11 patients without aura in monitoring also had absent or rare auras in their history. CONCLUSIONS: Lack of aura experience strongly correlates with indicators of bitemporal dysfunction such as bitemporal interictal sharp waves and bitemporal ictal propagation in scalp EEG, and absence of lateralized MRI sclerosis in patients with mesial TLE. The fact that absent auras are not correlated with episodic memory suggests a transient memory deficit, probably because of rapid propagation to the contralateral mesial temporal lobe.     

发作间期PET和MR海马像在难治性颞叶癫癇术前定侧中的应用

目的 探讨发作间期18FDG-PET和MR海马像在难治性颞叶癫(?)（TLE）致(?)源术前定侧中的价值。方法 对17例药物难治性TLE患者术前定侧资料及术后随诊情况进行分析。结果 本组患者中,有12例（71％）患者MR显示海马硬化（HS）,海马萎缩与信号改变常共存,T2加权像和FLAIR序列有利于显示信号的改变。HS侧多提示为致(?)源侧。PET检查均显示有至少一侧颞叶低代谢改变,并常多发或范围弥散。PET与MR的定侧准确率分别是100％（13/13）、77％（10/13）,经x2检验两者间无差异（P>0.05）。结论　18FDG-PET和MR海马像在致(?)源定侧中的作用是互补的,当颞叶低代谢侧与海马硬化侧相一致时手术效果较好。     

Spikes on the postoperative EEG are related to preoperative spike frequency and postoperative seizures

PURPOSE: To investigate the factors which influence the persistence of interictal epileptiform discharges (IED) after epilepsy surgery. METHODS: In this retrospective study we included patients with intractable medial temporal lobe epilepsy (MTLE) who underwent presurgical evaluation including high-resolution MRI and video-EEG monitoring with seizure registration prior to an anterior temporal lobe resection. The postsurgical outcome was assessed by our team 6 months and 2 years after the surgery. RESULTS: One hundred and forty-seven patients fulfilled the inclusion criteria. The mean age of the patients was 31.8 (range 16-59 years). In 22 patients (15%) interictal epileptiform discharges were present on the postoperative routine EEG. We found that both the preoperative spike frequency ( P < 0.001 ) and postoperative seizures ( P = 0.04 ) were independently associated with the presence of IED on the postoperative routine EEG. The preoperative spike frequency was not associated with the postoperative outcome. The extent of resection showed no influence on the presence of postoperative IED. CONCLUSION: We hypothesize that two factors independently influence the presence of postoperative spikes: chronic interictal disturbance (represented as preoperative spike frequency) and the acute (postoperative) seizures. Our study confirmed that persistent postoperative IED had a prognostic value regarding the outcome of the epilepsy surgery.