Navigation-assisted trans-inferotemporal cortex selective amygdalohippocampectomy for mesial temporal lobe epilepsy; preserving the temporal stem

Objective: Selective amygdalohippocampectomy (SAH) can be used to obtain satisfactory seizure control in patients with mesial temporal lobe epilepsy (MTLE). Several SAH procedures have been reported to achieve satisfactory outcomes for seizure control, but none yield fully satisfactory outcomes for memory function. We hypothesized that preserving the temporal stem might play an important role. To preserve the temporal stem, we developed a minimally invasive surgical procedure, ‘neuronavigation-assisted trans-inferotemporal cortex SAH’ (TITC-SAH).

Methods: TITC-SAH was performed in 23 patients with MTLE (MTLE on the language-non-dominant hemisphere, n = 11). The inferior horn of the lateral ventricle was approached via the inferior or middle temporal gyrus along the inferior temporal sulcus under neuronavigation guidance. The hippocampus was dissected in a subpial manner and resected en bloc together with the parahippocampal gyrus. Seizure control at one year and memory function at 6 months postoperatively were evaluated.

Results: One year after TITC-SAH, 20 of the 23 patients were seizure-free (ILAE class 1), 2 were class 2, and 1 was class 3. Verbal memory improved significantly in 13 patients with a diagnosis of hippocampal sclerosis, for whom WMS-R scores were available both pre- and post-operatively. Improvements were seen regardless of whether the SAH was on the language-dominant or non-dominant hemisphere. No major complication was observed.

Conclusion: Navigation-assisted TITC-SAH performed for MTLE offers a simple, minimally invasive procedure that appears to yield excellent outcomes in terms of seizure control and preservation of memory function, because this procedure does not damage the temporal stem. TITC-SAH should be one of the feasible surgical procedures for MTLE.

Abbreviations: SAH: Amygdalohippocampectomy; MTLE: Mesial temporal lobe epilepsy (MTLE); TITC-SAH: Ttrans-inferotemporal cortex SAH; ILAE: International League Against Epilepsy (ILAE); MRI: Magnetic resonance imaging; EEG: Electroencephalography (EEG); FDG-PET: ⁸F-fluorodeoxyglucose (FDG)-positron emission tomography; ECoG: Electrocorticography; MEG: Magnetoencephalography; IMZ-SPECT: N-isopropyl-p(¹²³I)-iodoamphetamine single photon emission computed tomography; WMS-R: Wechsler Memory Scale-Revised.     

Prognostic factors in anterior temporal lobe resections for mesial temporal lobe epilepsy: multivariate analysis

PURPOSE: Even though there have been several studies on the prognostic factors of temporal lobe epilepsy (TLE) after lobectomy, no studies have been performed for homogeneous mesial TLE. Furthermore, most studies on the predictors of outcome of epileptic surgery were based on univariate analyses and did not consider modern epileptic surgery investigation modalities such as brain magnetic resonance imaging (MRI) and positron emission tomography (PET). We attempted to identify the prognostic factors in anterior temporal lobectomy (ATL) for mesial TLE with multivariate analysis. METHODS: Ninety-three patients with mesial TLE (54 men and 39 women, mean age at surgery, 28.3 +/- 8.2 years) were included in the study. The primary outcome variable was the status of patients in the second postoperative year, classified as either seizure free (except aura), or not seizure free. Clinical, electroencephalographic, MRI, PET, Wada test, and pathological data were considered. RESULTS: Seventy-eight (84.0%) patients had remission of seizures. With univariate analysis, age at surgery (p < 0.001), epilepsy duration before surgery (p = 0.04), and ipsilateral hippocampal sclerosis on MRI (p = 0.02) were found to be significant. By using multivariate analysis, age at surgery (p = 0.001) and ipsilateral hippocampal sclerosis on MRI (p = 0.03) were found to be the most significant prognostic factors. CONCLUSIONS: Age at surgery and hippocampal sclerosis are independent prognostic factors for ATL in mesial TLE. These findings suggest that mesial TLE may be a progressive disorder, and surgical outcome is better when early ATL is performed.     

The use of radiosurgery for the treatment of mesial temporal lobe epilepsy and long-term results

Purpose: To determine the efficacy of gamma knife radiosurgery in the treatment of mesial temporal lobe epilepsy due to mesial temporal sclerosis. Methods: Between November 1995 and May 1999, 14 patients underwent radiosurgical entorhinoamygdalohippocampectomy with a marginal dose of 18, 20, or 25 Gy to the 50% isodose following a standard preoperative epilepsy evaluation. Results: One patient was classified as Engel Class Ib, three were Engel Class IIc, one was Engel Class IIIa, and two were Engel Class IVb in a subgroup of seven patients who were unoperated 2 years prior to the last visit and at least 8 years after irradiation (average 116 months). The insufficient effect of irradiation led us to perform epilepsy surgery on another seven patients an average of 63.5 months after radiosurgery. The average follow‐up period was 43.5 months after the operation. Four patients are seizure‐free; one is Engel Class IIb and one is Engel Class IId. One patient cannot be classified due to the short period of follow‐up. The frequency of seizures tended to rise after irradiation in some patients. Collateral edema was observed in nine patients, which started earlier and was more frequent in those irradiated with higher doses. It had a marked expansive character in three cases and clinical signs of intracranial hypertension were present in three cases. We found partial upper lateral quadrant anopia as a permanent side effect in two patients. Repeated psychotic episodes (two patients) and status epilepticus (two patients) were also seen after treatment. No significant memory changes occurred in the group as a whole. Discussion: Radiosurgery with 25, 20, or 18‐Gy marginal dose levels did not lead to seizure control in our patient series, although subsequent epilepsy surgery could stop seizures. Higher doses were associated with the risk of brain edema, intracranial hypertension, and a temporary increase in seizure frequency.     

Gamma knife surgery for mesial temporal lobe epilepsy

PURPOSE: Gamma knife radiosurgery (GK) allows precise and complete destruction of chosen target structures containing healthy and/or pathologic cells, without significant concomitant or late radiation damage to adjacent tissues. All the well-documented radiosurgery of epilepsy cases are epilepsies associated with tumors or arteriovenous malformations (AVMs). Results prompted the idea to test radiosurgery as a new way of treating epilepsy without space-occupying lesions. METHODS: To evaluate this new method, we selected seven patients with drug-resistant "mesial temporal lobe epilepsy" (MTLE).The preoperative evaluation program was the one we usually perform for patients selected for microsurgery of TLE [video-EEG analysis of seizures, foramen ovale electrode recording, magnetic resonance imaging (MRI) positron emission tomography (PET) scan, neuropsychological testing]. In lieu of microsurgery, the amygdalohippocampectomy was performed by using GK radiosurgery. RESULTS: Morphologic (MRI) signs of destruction of the target took place at 9 months after GK surgery. Since the treatment day, the first patient has been seizure free. Seizure improvement came more gradually for the following patients, and complete cessation of seizures occurred around the tenth month (range, 8-15 months). MRI shows that the amygdaloentorhinohippocampal target was selectively injured. No significant side effect (except one case of homologous quadrantanopia) or morbidity and no mortality was observed. The current follow-up is 24-61 months, and all (but one) patients are seizure free. CONCLUSIONS: This initial experience proves clearly the short-to middle-term efficiency and safety of GK for MTLE surgery. These results need further confirmation of long-term efficiency, but the introduction of GK surgery into epilepsy surgery can reduce dramatically its invasiveness and morbidity.     

深部电极引导伽玛刀治疗颞叶内侧癫痫(附21例临床分析)

目的探索深部电极引导伽玛刀治疗颞叶内侧癫痫的方法,初步评价治疗效果。方法治疗21例颞叶内侧癫痫患者,其中男性13例,女性8例,年龄18~59岁,平均34.2岁,病史3~20年,平均13.5年。用无框架立体定向机器人技术进行深部电极植入,并进行深部电极长程视频脑电监测。本组双侧植入5例,单侧植入16例,植入监测时间1~7天,平均监测2.2天。明确致痫灶后,安装头架,行头颅CT扫描定位,然后拔除深部电极,行头颅核磁扫描。对头颅CT与核磁进行融合,明确致痫灶接触电极的位置,进行伽玛刀治疗。治疗剂量:周边剂量8~13 Gy,平均9.8 Gy;中心剂量16~26 Gy,平均18.2 Gy;50%等剂量曲线。结果随访6~36个月,平均15个月,Engel’s效果分级:Ⅰ级2例,Ⅱ级4例,Ⅲ级9例,Ⅳ级6例(Ⅰ~Ⅲ级为治愈及有效)。有效率为71.4%。手术并发症:颅内积气2例,1周后自行吸收。无其他手术并发症。结论颞叶内侧癫痫深部电极探测明确致痫灶后,应用CT及核磁融合技术,在深部电极引导下进行伽玛刀低剂量治疗,初步治疗结果满意。     

Volumetric evidence of bilateral damage in unilateral mesial temporal lobe epilepsy

PURPOSE: We sought to analyze the contralateral volumes of the temporal pole, posterior segment of the temporal lobe, amygdala, hippocampus, and parahippocampal gyrus in patients with temporal lobe epilepsy (TLE) due to histologically proven mesial temporal lobe sclerosis (MTLS), seizure free for >or=4 years of postsurgical follow-up. METHODS: Forty-six (23 male) TLE patients, operated on between 1996 and 2001, with histopathologic diagnosis of MTLS, and a postsurgical follow-up of >or=4 years, had their temporal lobe structures manually segmented, measured, and compared with those of 23 normal volunteers, paired as groups for sex, age, and handedness. RESULTS: The mean volumes of the contralateral temporal pole, hippocampus, and parahippocampal gyrus in TLE patients were significantly lower than those in controls. CONCLUSIONS: MRI volumetric data show that the damage in TLE due to MTS may be more widespread and bilateral, even in patients with unilateral TLE by clinical and neurophysiological criteria. Our results are relevant to the discussion of epileptogenic mechanisms in TLE.     

海绵状血管瘤致颞叶内侧癫痫手术入路选择

目的探讨引起癫痫的颞叶内侧不同部位海绵状血管瘤（cA）的手术入路选择。方法对3例位于颞叶内侧不同部位CA导致癫痫发作的患者,分别采取经侧裂入路、颞上沟入路及颞下回入路手术切除病灶。结果所有病例术中病灶显露满意,均予以完全切除。术后随访4～8个月,3例患者均无癫痫发作。结论对位于颞叶内侧不同部位的CA应根据病灶的部位选择不同手术入路,有利于充分显露并完全切除病灶。     

伽玛刀治疗颞叶内侧癫痫疗效分析(附26例临床分析)

目的探讨伽玛刀治疗颞叶内侧癫痫的方法与疗效。方法2000年9月至2005年1月应用伽玛刀治疗颞叶内侧癫痫患者共26例,病程平均8年（4～42年）。治疗范围包括杏仁核,海马及部分海马旁回,50％等剂量曲线边缘剂量平均19Gy（15～20Gy）。结果随访0．7～5．03年,平均1．13年。26例患者中有10例发作完全消失,发作频率减少在50％以上的患者16例（62％）,在随访时间大于1．5年的9例患者中有6例发作完全消失,发作频率减少在50％以上的患者7例（77．8％）。所有患者中21例复查了核磁共振（MRI）,有14例在术后12个月前后出现局部水肿及血脑屏障破坏。全部病人未见头痛、记忆力下降、视束损伤等并发症。结论初步结果显示伽玛刀治疗颞叶内侧癫痫安全、有效,最终疗效评估仍需大量病例长期随访确定。     

前颞叶切除术或选择性海马杏仁核切除术治疗顽固性内侧颞叶癫痫患者神经心理功能改变的研究

目的 探讨前颞叶切除术(ATL)或选择性海马杏仁核切除术(SAH)治疗顽固性内侧颞叶癫痫(MTLE)患者神经心理功能的改变情况。方法 选择2010年1月-2014年12月来本院接受ATL或SAH治疗的MTLE患者60例; 根据MTLE手术部位分为左颞部MTLE组(n=35)和右颞部MTLE组(n=25); 利用神经心理功能评分系统(DST、VMPT、WMSLM、WMS视觉、BNT、视觉技能、Stroop、WCST、分类、VFT)对患者术前及术后1年神经心理功能进行评分,比较2组患者左右颞部手术前后神经心理测试及手术前后左右颞部神经心理测试差异。结果 60例MTLE患者中35例(58.33%)左颞部MTLE,25例(41.67%)右颞部MTLE; 2组患者在性别、年龄、手术方式、癫痫发作平均年龄、病程、术前WAIS评分方面无显著性差异(P>0.05); 2组患者左右颞部手术前后神经心理测试比较显示,右颞部MTLE组术后在最大学习得分、短时记忆得分、长时记忆得分、第5卡片时间、矫正、转换错误方面与术前比较有显著差异(P<0.05); 左颞部MTLE组术后在合计得分方面与术前比较有显著差异(P<0.05); 2组患者手术前后左右颞部神经心理测试比较显示,左颞部MTLE组在回忆得分、识别得分、短时记忆得分方面显著高于右颞部MTLE组(P<0.05)。结论 尽管ATL或SAH治疗顽固性MTLE患者会引起部分常见的认知副作用,但该手术治疗也可提高患者部分认知功能。     

Prognostic factors for the surgery for mesial temporal lobe epilepsy: longitudinal analysis

PURPOSE: Determining long-term prognostic factors of surgery for mesial temporal lobe epilepsy (MTLE) is important for identifying ideal candidates and predicting the prognosis for individual patients. We tried to identify the prognostic factors of anterior temporal lobectomy (ATL) for MTLE with longitudinal multivariate analysis. METHODS: Two hundred twenty-seven patients with MTLE were included in this study. The primary outcome variable was patient status 1-5 years after surgery: seizure free, or not. Clinical characteristics and recent diagnostic modalities were considered as prognostic factors. Univariate and standard multiple logistic-regression analysis for outcome at 1 and 5 years after surgery and the generalized estimation equation (GEE) model for longitudinal multiple logistic regression of the 5-year follow-up period were used. RESULTS: The seizure-free rate at 1 year was 81.1% and decreased to 75.2% at 5 years after surgery. By the univariate or standard multiple logistic-regression analysis, age at surgery or hippocampal sclerosis on magnetic resonance imaging (MRI) ipsilateral to surgery was significant for the postsurgical outcome. However, the longitudinal analysis by the GEE model revealed that younger age at surgery [odds ratio (OR), 0.59; 95% confidence interval (CI), 0.43-0.81], absence of secondarily generalized tonic-clonic seizure (2 degrees GTCS; OR, 0.45; 95% CI, 0.26-0.79), and hippocampal sclerosis on MRI (OR, 2.44; 95% CI, 1.11-5.26) were significant predictors of a good surgical outcome. CONCLUSIONS: Age at surgery, presence of 2 degrees GTCS, and hippocampal sclerosis on MRI are independent prognostic factors for ATL in MTLE. These findings suggest that MTLE is a progressive disorder, and surgical outcome is better when early ATL is performed.     

Memory in patients with drug-responsive mesial temporal lobe epilepsy and hippocampal sclerosis

PURPOSE: Mesial temporal lobe epilepsy associated with hippocampal sclerosis (MTLE-HS) is the most common of the antiepileptic drug (AED)-resistant seizure syndromes that are remediable mostly with surgery, although a small group of patients have benign prognosis with fewer seizures. Material-specific memory impairment is an important feature in these patients and may be related to both the structural abnormality and the frequent seizures. In this study, we investigated the relation between memory deficit and HS by taking seizure frequency into account. METHODS: The patients were evaluated according to a standard protocol and divided into two groups, considering their response to AEDs: the good-responder group (GRg, n = 18) and the pharmacoresistant group (PRg, n = 95). They were administered a neuropsychological test battery that included verbal and nonverbal memory tests, compared with each other and with a normal control group (n = 29). The responder group was evaluated by the same battery once again (mean, 23 months; SD, 8.25; range, 14-38 months). RESULTS: Both GR and PR patient groups had poorer memory than the normal controls in all memory tests (p < 0.05). However, the comparison of GRg with PRg revealed that only the digit-span test was significantly worse in PRg (p = 0.0061), and no difference was found in any other memory scores. The reevaluation of the GRg showed no significant difference between the first and second evaluation. CONCLUSIONS: We concluded that the memory impairment in patients with MTLE-HS was permanent and might be related to the direct effect of HS itself. Therefore patients with good response to AEDs can be used as a model for investigating the memory problems in patients with MTLE-HS.     

Extent of initial injury determines language lateralization in mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS)

Purpose :  To assess the prevalence and attributes of atypical language lateralization (ALL) in patients with left mesial temporal lobe epilepsy associated with hippocampal sclerosis (MTLE-HS).
Methods :  We recruited consecutive patients with left MTLE-HS, who had undergone resective surgery and had pathologically proven HS. Based on the Wada test, language lateralization was classified into typical (left hemispheric) or atypical (right hemispheric or codominant). We assessed the attributes of patients with ALL using univariate and multivariate analyses.
Results :  Of 124 patients with left MTLE-HS, 23 (18.5%) had ALL. ALL occurred more frequently in patients with severe initial precipitating injury (IPI), early onset of epilepsy, and a short latent period between IPI and onset of habitual seizures. ALL was more common in patients with bitemporal and extratemporal interictal epileptiform discharges (IEDs) on electroencephalogram (EEG) and extratemporal changes on magnetic resonance imaging (MRI). On multivariate analyses, the age at onset of habitual seizures <6 years, atypical IPI, nonunilateral temporal IEDs, and extratemporal MRI abnormalities independently predicted ALL. The likelihood of ALL was very low (∼1%) when all of these four risk factors were absent, whereas it was very high (>95%), if any three or all four of them were present.
Conclusions :  ALL occurs in one-fifth of patients with left MTLE-HS. ALL is more frequent in those with structural or functional extrahippocampal involvement and early onset of epilepsy interrupting the development of normal language networks. Because ALL is uncommon in those with damage/dysfunction restricted to the hippocampus, the hippocampus itself may have only a limited role in determining language lateralization.     

Prognostic factors in patients with mesial temporal lobe epilepsy

Purpose:   To disclose clinical, electrophysiologic, and neuroradiologic factors correlated to prognosis in patients with mesial temporal lobe epilepsy (MTLE).
Methods:   One hundred thirty-six MTLE patients were studied for family history, clinical characteristics, instrumental data [electroencephalography (EEG), video-EEG, neuroimaging], and outcome. The population was divided into drug-resistant (DR: 108 patients, 79.4%) and non–drug-resistant (NDR: 28 patients, 20.6%) groups; all variables were analyzed in the two groups.
Results:   The comparison between the two groups shows a relation between resistance to therapy and febrile seizures (FS) (DR 43.5% vs. NDR 17.8%, p = 0.008), mesial temporal sclerosis (MTS) (DR 64.8% vs. NDR 32.1%, p = 0.0025), early age at seizure onset (DR 23.1% vs. NDR 3.6% p = 0.0160), and epileptiform interictal abnormalities (DR 89.7% vs. NDR 68%, p = 0.010). FS were more frequent in patients with MTS than in patients without (46.28% vs. 26.3%, p = 0.0199). Sixty-nine patients underwent surgery and 85.3% of them had a good outcome.
Conclusion:   MTLE is a heterogeneous syndrome. Establishing the factors responsible for and associated with drug resistance is important for therapeutic purposes, as prompt diagnosis of drug resistance must lead to early surgical management. This study shows that FS, MTS, early age at seizure onset, and epileptiform interictal abnormalities are negative prognostic factors and that FS are related to MTS.     

The influence of seizure frequency on anterograde and remote memory in mesial temporal lobe epilepsy

PurposeSeizure frequency, although considered as an important factor in memory impairment in mesial temporal epilepsy (mTLE), is mostly confounded with other clinical variables, making it unclear to what extent recurrent seizures actually interfere with memory. The present study focuses on the influence of seizure frequency, studied as a main variable, on anterograde and remote memory.MethodsSeventy-one patients with unilateral mTLE were divided into two subgroups, as a function of their seizure frequency (monthly versus weekly seizures). Other seizure-related variables were controlled, namely, lateralisation and type of lesion, age at onset, years of ongoing seizures, etiologic factors, and number of AED. A comprehensive neuropsychological examination, including anterograde memory (verbal and non verbal recognition memory and free recall) tasks together with a large range of tests exploring different domains of remote memory, was carried out.ResultsDespite similar results on IQ, executive functions and attention, the low seizure-frequency group performed significantly better than the high seizure-frequency group on anterograde memory tests. Loss of autobiographical episodes and public-events memory, concomitant with spared personal semantic knowledge, was observed in both patient groups compared with healthy subjects. A worsening effect of high seizure frequency was recorded for autobiographical incidents and news-events memory, but unexpectedly, not for memory for famous people.ConclusionThe study of seizure frequency as the main variable leads us to suggest that high seizure frequency, itself, potentiates the effects of mesial temporal lobe damage on episodic memory deficits.     

颞叶内侧癫痫的两种术式对发作控制的对比分析

目的观察前颞叶切除术和选择性海马、杏仁核切除术对颞叶内侧癫痫的发作控制效果是否有差别。方法 2009年1月至2010年12月在我科行前颞叶切除术的67例颞叶内侧患者为A组;2011年6月至2013年5月在我科行选择性海马、杏仁核切除术的46例颞叶内侧患者为B组;统计分析两组术后1年发作控制为Engel I-II级和Engel III-IV级的人数。结果 A组Engel I-II级56例(83.58%),Engel III-IV级11例(16.42%);B组Engel I-II级40例(86.95%),Engel III-IV级6例(13.05%)。经χ2检验两组术后对MTLE发作的控制率无统计学差异,χ2=0.243,P0.05。结论前颞叶切除术和选择性海马、杏仁核切除术对颞叶内侧癫痫发作都能获得良好的控制,两者疗效无明显差异。     

Spontaneous periictal leaving behavior: A potential lateralizing sign in mesial temporal lobe epilepsy

Purpose:   Seizure-related spontaneous leaving behavior (LB) is an uncommonly reported phenomenon. The aim of this study was to determine its frequency, clinical significance, and especially its lateralizing value.
Methods:   We analyzed retrospectively the spontaneous periictal LB occurring in complex partial seizures (CPS) of 138 patients with medically refractory mesial temporal lobe epilepsy (MTLE) with excellent postoperative seizure outcome and pathologic finding of hippocampal sclerosis. The relation of LB occurring in different phases of CPS to the side of resection was investigated.
Results:   The overall frequency of periictal LB was 8.3% of 517 CPS and 25.2% of 123 patients. Among the 12 patients with ictal LB, 9 patients had epileptogenic focus ipsilateral to language dominant side, whereas the remaining 3 had seizure onset in the nondominant side. Conversely, 8 of 11 patients with postictal LB had foci in the nondominant side, and only three patients' seizures originated in the dominant side. Therefore, it was more likely for patients with left MTLE to show ictal LB and for those with right foci to display postictal LB (p = 0.03).
Conclusions:   LB may represent a potential lateralizing sign. When LB occurs ictally, it may indicate seizure onset in the dominant temporal lobe, and LB occurring postictally indicates nondominant side seizure onset in patients with MTLE.     

难治性颞叶癫(癎)的手术治疗

目的 探讨难治性颞叶癫(癎)的手术疗效.方法 回顾性分析2003年7月至2007年2月我科手术治疗的72例难治性颞叶癫(癎)患者临床资料.结果 按我国谭氏标准,满意:59例;显著改善:2例;良好:3例;效差:2例;无改善:5例;死亡:1例.结论 手术治疗难治性颞叶癫(癎)疗效确切可靠,在有条件的医院可推广.     

Upregulation in astrocytic connexin 43 gap junction levels may exacerbate generalized seizures in mesial temporal lobe epilepsy

Following brain injury, and during the process of neurodegeneration, a reactive astrocytic proliferation occurs. This is accompanied by an increase in the synthesis of neuropeptides, cytokines, growth factors and glial fibrillary acidic protein (GFAP), a cell-specific marker for reactive astrocytes. Astrocytes are extensively coupled by gap junctions of the Cx43 connexin subtype. Several studies have shown that in severe trauma, coupling between astrocytes may add to the spread of the damaged area. In this study we ask whether the astrocytosis which is a feature of other neurodegenerative diseases also occurs in mesial temporal lobe epilepsy (MTLE) and whether it is accompanied by an increase in astrocytic communication through an upregulation of Cx43 gap junction channel proteins. In order to examine the astrocytic response and the expression pattern of Cx43 protein, double immunohistochemical labeling studies were undertaken using antibodies against GFAP and Cx43 applied to human hippocampal tissue resected from patients with MTLE, and to normal human control hippocampal tissue. Immunofluorescent labeling of astrocytes and Cx43 was examined using confocal laser scanning microscopy. The images obtained were quantitatively analysed and reconstructed using three-dimensional volume rendering. The results of this study have established that not only is astrocytosis greater in MTLE-affected tissues than previously suggested, but it is accompanied by a highly significant increase in astrocytic Cx43 protein levels. We hypothesize that this surprisingly large upregulation in Cx43 may exacerbate generalized seizures in the progression of MTLE.     

Predictive value of MRI-identified mesial temporal sclerosis for surgical outcome in temporal lobe epilepsy: an intent-to-treat analysis

PURPOSE: Magnetic resonance imaging (MRI) accurately identifies mesial temporal sclerosis (MTS), but prediction of successful surgical outcome ranges from 62% to 96% in published studies. Prior investigations only used patients who had received anterior temporal lobectomy (ATL), potentially overestimating the predictive value of MRI-identified MTS (MRI-MTS). METHODS: The authors performed an intent-to-treat analysis of 90 consecutive patients assessed for possible ATL, including 13 who did not undergo ATL because of inconclusive intracranial ictal EEG. Four (31%) of these 13 patients had unilateral mesial temporal abnormalities on their MRIs. RESULTS: The positive predictive value of MRI-MTS for seizure cessation decreased from 0.69 to 0.63 after adjustment for these additional false positive results. Four previous studies had revealed a positive predictive value of 0.75 (0.72 after similar adjustment). CONCLUSIONS: The authors conclude that the predictive value of MRI-MTS for outcome from ATL may be overestimated by small retrospective studies of highly selected postoperative patients.