Epilepsy surgery in children with focal cortical dysplasia (FCD): results of long-term seizure outcome

The purpose of this study was to assess the effect of epilepsy surgery on seizure outcome in children and adolescents under 18 years with intractable epilepsy due to focal cortical dysplasia. We analysed clinical data, such as age at seizure onset, epilepsy course, localisation of focus from presurgical evaluation, MRI, tissue pathology and seizure outcome in 68 patients 6 months to 9 years after epilepsy surgery. Seizure outcome was classified according to the Engel classification. Mean age at seizure onset was 7 months, ranging from the first days of life to 7 years. All patients had medically intractable epilepsy. Localisation of the lesion was predominantly extratemporal: posterior (uni- or multilobar) 43 %, frontal without central region 26 %, multilobar involving central area 19 % and temporal in 12 %. MRI signs typically seen in cortical dysplasia (FCD) such as localised blurring of gray-white matter junction was found in 68 %, dysgyria in 62 %, thickening of the cortical ribbon in 46 % and T2 signal elongation of the subcortical white matter in 40 % of the patients' MRI. Age at surgery ranged from 5 months to 16 years; 14 patients were under 2 years when operated on. In 34 patients (6 patients under 3 years) subdural grid electrode evaluation was performed prior to surgery. Pathology revealed focal cortical dysplasia without balloon cells (type I) in 60 %, FCD of the balloon cell subtype (type II) in 40 % of the specimens. Postoperative complications were subdural hygroma in 5 and an increased motor deficit in 2 patients. Up to two years after epilepsy surgery 50 % of the children were seizure free (Engel class I), 10 % Engel class II, 33 % Engel class III and 7 % unchanged (Engel class IV). Long-term seizure outcome (> 3 years post surgery) in 32 patients showed similar results (class I 50 %, class II 19 %, class III 28 %, class IV 3 %). Complete resection of the dysplastic lesion was significantly correlated with favorable seizure outcome, whereas seizure outcome was not significantly different in patients with mild (type I) or balloon cell (type II) FCD. Children operated after 6 years of age had no better outcome than children operated in infancy or at preschool age. Epilepsy surgery resulted in good (class I and II) seizure control in 60 % of children with intractable epilepsy due to focal cortical dysplasia.     

Comparison of MRI features and surgical outcome among the subtypes of focal cortical dysplasia

PurposeFocal cortical dysplasia (FCD) is the most common pathological diagnosis in patients who have undergone surgical treatment for intractable neocortical epilepsy. However, presurgical identification of MRI abnormalities in FCD patients remains difficult, and there are no highly sensitive imaging parameters available that can reliably differentiate among FCD subtypes. The purpose of our study was to investigate the surgical outcome in FCD patients with identifiable MRI abnormalities and to evaluate the prognostic role of the various MRI features and the characteristics of FCD pathology.MethodsWe retrospectively recruited epilepsy patients who had undergone surgical treatment for refractory epilepsy with focal MRI abnormalities and the pathological diagnosis of FCD. We evaluated the surgical outcome according to the pathological subtypes, and studied the prognostic roles of various MRI features. We used recently proposed three-tiered FCD classification system which included FCD type III when FCD occurs in association with other potentially epileptogenic pathologies.ResultsA total of 69 patients were included, and 68.1% of patients became seizure free. Patients with FCD type III had a lower chance for achieving seizure freedom (7/15) than in patients with isolated FCD (FCD types I and II) (40/54, p = 0.044). Cortical thickness and blurring of gray–white matter junction were more common in isolated FCD than in FCD type III, but most MRI features failed to differentiate between FCD types I and II, and only the transmantle sign was specific for FCD type II. We failed to find a prognostic value of specific MRI abnormalities of prognostic value in terms of post-epilepsy surgery outcome in FCD patients.ConclusionsOur study showed that patients with FCD III have poor surgical outcome. Typical MRI features of isolated FCD such as cortical thickness and blurring of gray–white matter junction were less common in FCD type III and only transmantle sign was helpful in differentiating between FCD types I and II.     

Low-grade focal cortical dysplasia is associated with prenatal and perinatal brain injury

Purpose: Prenatal and perinatal adverse events are reported to have a pathogenetic role in focal cortical dysplasia (FCD). However, no data are available regarding the prevalence and significance of this association. A cohort of children with significant prenatal and perinatal brain injury and histologically proven mild malformations of cortical development (mMCD) or FCD was analyzed. Methods: We retrospectively evaluated a surgical series of 200 patients with histologically confirmed mMCD/FCD. Combined historical and radiologic inclusion criteria were used to identify patients with prenatal and perinatal risk factors. Electroclinical, imaging, neuropsychological, surgical, histopathologic, and seizure outcome data were reviewed. Results: Prenatal and perinatal insults including severe prematurity, asphyxia, bleeding, hydrocephalus, and stroke occurred in 12.5% of children with mMCD/FCD (n = 25). Their epilepsy was characterized by early seizure onset, high seizure frequency, and absence of seizure control. Patients with significant prenatal and perinatal risk factors had more abnormal neurologic findings, lower intelligence quotient (IQ) scores, and slower background EEG activity than mMCD/FCD subjects without prenatal or perinatal brain injury. MRI evidence of cortical malformations was identified in 74% of patients. Most patients underwent large multilobar resections or hemispherectomies; 54% were seizure‐free 2 years after surgery. Histologically “milder” forms of cortical malformations (mMCD and FCD type I) were observed most commonly in our series. Conclusions: Surgically remediable low‐grade cortical malformations may occur in children with significant prenatally and perinatally acquired encephalopathies and play an important role in the pathogenesis of their epilepsy. Presurgical detection of dysplastic cortex has important practical consequences for surgical planning.     

A longitudinal study of surgical outcome and its determinants following posterior cortex epilepsy surgery

Purpose:   To investigate the longitudinal seizure outcome and identify potential prognostic indicators following posterior cortex epilepsy (PCE) surgery.
Methods:   We reviewed patients who underwent a parietal, occipital, or parietooccipital resections between 1994 and 2006, using survival analysis and multivariate regression with Cox proportional hazard modeling. A favorable outcome was defined as Engel Class I at last follow-up.
Results:   Fifty-seven patients were identified with a mean follow-up of 3.3 years (range 1–12 years). The estimated chance of seizure freedom (SF) was 73.1% at 6 postoperative months, 68.5% at 1 year, 65.8% at between 2 and 5 years, and 54.8% at 6 years and beyond. Most recurrences (75%) occurred within the first 6 postoperative months. Parietal resections had a worse outcome than occipital or parietooccipital resections (52% SF vs. 89% and 93%, respectively, at 5 years). Independent predictors of recurrence included an epilepsy etiology other than tumor or dysplasia [risk ratio (RR) 2.29], limiting resection to a lesionectomy (RR 2.10), having ipsilateral temporal spiking on preoperative scalp electroencephalography (EEG) (RR 2.06), or any ipsilateral spiking on postoperative EEG (RR 2.70) (Log likelihood-ratio test p < 0.0001). Only 40–50% of patients with a poor outcome predictor were SF at 5 postoperative years as opposed to about 80% otherwise. In surgical failures, recurrent seizure frequency was related directly to baseline seizure frequency and to the presence of ipsilateral spiking on postoperative EEG.
Discussion:   These data highlight favorable long-term outcomes following PCE surgery. Limited surgical resection and diffuse baseline epileptogenicity may be important predictors of seizure recurrence.     

Infantile spasms in tuberous sclerosis complex: prognostic utility of EEG

Purpose:   To assess cognitive and epilepsy outcomes in tuberous sclerosis complex (TSC) patients with a history of infantile spasms (IS), in relation to spasm history, electroencephalography (EEG) characteristics, genetic mutation, and treatment history.
Methods:   The authors conducted a retrospective review of 45 children and adults with TSC and a history of IS. EEG reports from the time of spasms were evaluated for all patients, and EEG tracings were accessible and evaluated for 20 patients.
Results:   Clinical outcome was unfavorable for the majority of patients. However, 33% had experienced at least one year of seizure freedom at follow-up, and 24% of those tested had IQs above 70. Hypsarrhythmia severity scores varied widely, with some EEGs severely hypsarrhythmic and others essentially normal. Lower IQ was significantly associated with higher hypsarrhythmia severity scores on EEG report, the presence of background disorganization on EEG report, the absence of normal sleep patterns on EEG, and a lower degree of treatment success on vigabatrin. A relationship between poor cognitive outcome and poor epilepsy outcome was confirmed. The correlation between poor epilepsy outcome and a greater degree of background disorganization on EEG approached significance, as did the association between subsequent intractable epilepsy and an older age at IS cessation. A greater than expected ratio of TSC2 to TSC1 patients was observed across this IS population.
Discussion:   Early detection and successful treatment portend a more favorable outcome in TSC patients with IS. Although EEG findings in these patients vary, specific characteristics may serve as clinically useful prognostic markers.     

Outcome after corticoamygdalohippocampectomy in patients with refractory temporal lobe epilepsy and mesial temporal sclerosis without preoperative ictal recording

Purpose:   We report on the surgical outcome obtained in patients with refractory temporal lobe epilepsy with mesial temporal sclerosis (MTS) who were evaluated preoperatively without ictal recording and were submitted to corticoamygdalohippocampectomy.
Methods:   Two hundred twelve patients with refractory temporal lobe epilepsy were evaluated by means of clinical history, neurological examination, interictal electroencephalography (EEG), magnetic resonance imaging (MRI), and neuropsychological testing. MRI disclosed unilateral MTS in all patients. All patients were submitted to corticoamygdalohippocampectomy at the side determined by MRI.
Results:   Interictal EEG showed unilateral temporal lobe spiking in 176 patients; in 36 patients, bilateral discharges were found. Mean follow-up time was 2.7  years. One hundred ninety-four patients (92%) were classified as Engel's class I. Eighteen patients (8%) were rated as Engel's class II. Thirty-two out of 36  patients, in whom bilateral discharges were found, were in Engel's class I. Sixty percent of the patients had an improvement in memory function related to the nonoperated temporal lobe. Fifty-nine percent of the patients had a 10-point increase in general IQ postoperatively. Verbal memory decline was noted in three patients. Pathological examination showed MTS in all patients.
Conclusions:   It is possible to adequately select good surgical candidates for temporal lobe resection using MRI and interictal EEG alone. In patients with MRI-defined MTS, we should expect a 90% postoperative remission rate. Cognitive decline was very rarely seen in this patient population. The finding of MTS on MRI is the single most important prognostic factor for good outcome after temporal lobe surgery.     

Outcome after hemispherectomy in hemiplegic adult patients with refractory epilepsy associated with early middle cerebral artery infarcts

Purpose:   To study the outcome after hemispherectomy (HP) in a homogeneous adult patient population with refractory hemispheric epilepsy.
Methods:   Fourteen adult patients submitted to HP were studied. Patients had to be at least 18 years old, and have refractory epilepsy, clearly focal lateralized seizures and unilateral porencephalus consistent with early middle cerebral artery infarct on magnetic resonance imaging (MRI). All patients were submitted to functional hemispherectomy. We analyzed age of seizure onset, age by the time of surgery, gender, seizure type and frequency, interictal and ictal electroencephalography (EEG) findings, MRI and IQ scores preoperatively; seizure frequency, drug regimen, and IQ outcome were studied postoperatively.
Results:   Mean follow-up was 64 months. All patients had frequent daily seizures preoperatively. All patients had unilateral simple partial motor seizures (SPS); 11 patients had secondarily generalized tonic–clonic (GTC) seizures and five patients had complex partial seizures (CPS), preoperatively. All patients had hemiplegia and hemianopsia. Twelve patients had unilateral EEG findings, and in two epileptic discharges were seen exclusively over the apparently normal hemisphere. Twelve patients were seizure-free after surgery and two patients had at least 90% improvement in seizure frequency. Pre- and postoperative mean general IQ was 84 and 88, respectively. Five of the twelve Engel I patients were receiving no drugs at last follow-up. There was no mortality or major morbidity.
Conclusions:   Our results suggest that well-selected adult patients might also get good results after HP. Although good results were obtained in our adult series, the same procedure yielded a much more striking result if performed earlier in life.     

Early Discontinuation of Treatment in Children with Uncomplicated Epilepsy: A Prospective Study with a Model for Prediction of Outcome

Summary: Purpose: The main purpose of the present study was to identify predictor variables with significant influence on seizure outcome after discontinuation of treatment in children with uncomplicated epilepsy and to analyze whether these variables, included in a prognostic model could identify children in whom 1-year treatment would be sufficient.
Methods: Before initiation of treatment in children aged 2–16 years with uncomplicated epilepsy, the duration of treatment was randomized to 1 year (group I) or 3 years (group II). At the end of the allotted period, treatment was discontinued in 161 children who had been seizure free during the previous 6 months. The mean follow-up period after treatment was 5.8 years. Twenty-three predictor variables were analyzed by survival methods regarding their influences on the outcome.
Results: At the latest follow-up check, 60 children (37%) had relapsed. The following predictor variables were selected by multiple regression analysis and constituted a model with a simple scoring system: age at seizure onset; seizure type; generalized, irregular spike-wave activity on EEG after 1 year of treatment; and persistent 3-Hz spike-wave activity after 6 months of treatment in children with absence epilepsy. In group I, the remission rate was 73% in children with high prognostic scores, 10% in children with low scores, and 40% in those with intermediate scores (log-rank test, p = 0.0001).
Conclusions: After 1 year of treatment, our prognostic model identified children in whom treatment could be withdrawn at that time. Our model should be easily applicable in clinical practices and may be of clinical importance in determining the duration of treatment in children with uncomplicated epilepsy.     

Clinical characteristics,pathological features and surgical outcomes of focal cortical dysplasia (FCD) type II: correlation with pathological subtypes

Focal cortical dysplasia (FCD) type II is a major cause of drug-resistant epilepsy. In order to gain insight into the possible correlations between FCD II pathological pattern and different clinical characteristics (including clinical information, imaging characteristics and surgical outcomes), different clinicopathological characteristics in two types of FCD II were analyzed (especially in FCD IIb). The mean age of seizure onset and disease duration of 78 patients was 11.0 and 11.2 years, respectively. Patients with FCD type IIb had earlier seizure onset compared with those with FCD type IIa. Pathological subtype IIb was predominantly in frontal lobe and subtype IIa was predominantly seen in temporal. Type IIb demonstrated significantly more signal abnormalities in fluid attenuated inversion recovery (FLAIR) images and T2 images than Type IIa. The rate of satisfactory seizure outcome was 67.64 % in the FCD IIa group, while relative higher, 88.63 %, in the FCD IIb group. All these characteristics may assist in their earlier diagnosis and improve the predictability of surgical management.     

Focal cortical dysplasias in temporal lobe epilepsy surgery: Challenge in defining unusual variants according to the last ILAE classification

ObjectiveFocal cortical dysplasias (FCDs) represent a common architectural cortical disorder underlying pharmacoresistant focal epilepsy. The recent ILAE classification defines different types of FCDs based on their histopathological features, MRI imaging, and presumed pathogenesis; however, their clinical features and their prognostic significance are still incompletely defined. In addition, the combination of different histopathological abnormalities can represent “unusual” subtypes that can be difficult to classify. The aim of our study was to analyze the incidence and the significance of these “unusual” subtypes of FCDs in drug-resistant mesial temporal lobe epilepsy (MTLE).MethodsWe retrospectively analyzed 133 patients consecutively submitted to tailored anteromesial temporal lobe resection for pharmacoresistant MTLE. Seizure onset, seizure duration, age at surgery, and postoperative seizure outcome were evaluated in relation to the different neuropathological groups defined according to the new ILAE classification.ResultsFocal cortical dysplasias were found in 80 out of 133 patients. Six patients were affected by isolated FCD type I, 12 patients by FCD type II, and 44 patients by FCD type III. Furthermore, we found 18 “atypical” cases (20.5% of all FCD cases and 26.6% of FCDs associated with a principal lesion): 10 cases of associated FCD type II–hippocampal sclerosis (HS) and 8 cases associated with FCD II–epilepsy-associated tumors (EATs).ConclusionOur results indicate that “unusual” subtypes of FCDs, in particular associated FCD type II, are not uncommon findings, suggesting that they deserve a classification recognition. Similarities in seizure outcome and immunohistochemical and molecular evidences, shared by FCD type II + EATs and EATs, suggest a common pathogenic link. The choice to create a specific unifying class or, on the contrary, to also include “associated FCD type II” in the definition of the new unifying class FCD type III should be further discussed.     

Focal Cortical Dysplasias: clinical implication of neuropathological classification systems

Focal Cortical Dysplasias (FCDs) are highly epileptogenic brain lesions and are a frequent cause for drug-resistant focal epilepsies in humans. FCDs present with variable histopathological patterns, including architectural, cytoarchitectural or white matter abnormalities. Pathomechanisms compromising neuroblast proliferation, migration, or differentiation are likely to play a role in the etiology of FCD variants. FCDs were subsumed, therefore, into the broad spectrum of malformations of cortical development. The most frequent subtype comprises FCD Type II, which in general occurs as isolated lesion in extratemporal location and is histopathologically characterized by dysmorphic neurons (Type IIA) and balloon cells (Type IIB). Neuroimaging hallmarks include hyperintense T2-signaling and a “transmantle sign”. Electrophysiological recordings show peculiar interictal spike patterns and complete surgical resection results in favorable seizure control. In contrast, FCD Type I can be identified in young children with severe epilepsy and psychomotor retardation. Parietal, temporal, and occipital lobes may be involved in seizure generation, although neuroimaging often reveals normal contrast intensities. Surgical resection strategies ameliorate seizure frequencies in many children, whereas complete seizure relief can be achieved only in rare cases. According to the currently used FCD classification system, the same histopathological FCD Type I variant can be diagnosed as associated lesion in the large cohort of epilepsy patients with hippocampal sclerosis, low-grade glio-neuronal tumors, vascular malformations, or glial scarring. MRI is often not helpful to detect the dysplastic cortical areas. In addition, there is no specific electrophysiological pattern for an associated dysplastic lesion. Surgical resection of the epileptogenic area results, however, in favorable seizure control. These findings argue for a revised neuropathological classification system that distinguishes isolated versus associated FCD variants to obtain a better correlation with electro-clinical findings and prediction of postsurgical seizure control.     

Clinical characteristics and post-surgical outcomes of focal cortical dysplasia subtypes

We retrospectively studied 105 patients with a focal cortical dysplasia (FCD) diagnosed on pathological examination, and investigated the long term postoperative seizure outcomes, different clinical characteristics of the three FCD subtypes, particularly type I and II, and surgical outcomes for each group. FCD is a common cause of drug-resistant epilepsy, which is divided into three different subtypes according to its involvement at different stages of brain development. Each of these groups may have different characteristics and may even have different surgical outcomes. After treatment, 55% of patients were completely seizure-free, with two significant predictive variables for poorer outcomes: focal MRI findings and electrode implantation. FCD type I had relatively poor surgical outcomes compared to FCD type II and type IIIa. Compared with FCD type I, type II, particularly IIb, had a higher frequency of seizure attacks, predominantly located in the extratemporal lobes, and was more readily detected and diagnosed via focal lesions on MRI and localized electroencephalogram abnormalities. FCD type II patients seem to show better surgical outcomes than FCD type I, but the difference was not significant. Larger cohort studies are needed for further evaluation of the seizure outcomes of different FCD subtypes.     

Role of MRI in patient selection for surgical treatment of intractable epilepsy in infancy

Epilepsy surgery is an effective treatment in selected patients with localization-related intractable epilepsy. The success of epilepsy surgery is in part dependent upon identification of a lesion on MRI. In infants, the surgical epileptogenic substrates include focal cortical dysplasia (FCD), hemimegalencephaly, tuberous sclerosis complex, Sturge Weber syndrome, hypoxic-ischemic or cerebrovascular injury and low-grade tumor. The sensitivity of MRI in identifying the epileptogenic substrate is influenced by the nature of the epileptogenic substrate, MRI technique and expertise of the interpreting physician. The MRI features of some lesions such as FCD may differ in infants compared to children and adults; the white matter adjacent to FCD may demonstrate lower T2 and higher T1 signal in some infants due to premature myelination, while in others, the white matter demonstrates higher T2 or lower T1 signal due to demyelination, dysmyelination or gliosis, similar to children and adults. The appearances of some lesions, such as FCD, may change with time, due to brain maturation or seizure related changes. MRI for patients with localization-related intractable epilepsy should have high-resolution, multiplanar and multisequence. In infants, volumetric T1 and high-resolution T2 imaging are recommended. FLAIR and proton density sequences are less helpful in infants due to lack of myelin in the white matter. The physician interpreting the scan should be familiar with the imaging appearances of epileptogenic substrates and may need to review the scan more than once if a lesion is not seen on initial inspection.     

Which patients become seizure free with antiepileptic drugs? An observational study in 821 patients with epilepsy

Objectives –  Analysis of factors influencing seizure outcome in antiepileptic drug treatment of epilepsy.
Patients and methods –  Retrospective analysis of 500 patients with complete seizure control and 321 patients with refractory epilepsy (mean ages 33.3 and 32.1 years respectively).
Results –  The seizure-free group consisted of 377 patients with symptomatic/cryptogenic epilepsy (SCE; mean seizure control 45 months) and 123 patients with idiopathic generalized epilepsy (IGE; mean seizure control 61 months) ( P  = 0.02). Of the patients with SCE, 35.7% had achieved seizure control with monotherapy (MT), 29.6% with ≥2 AEDs. No single AED was superior in MT. Of the patients with IGE, 35.9% had become seizure free with MT, 15.6% on combination therapy (CT). Valproate MT was more commonly associated with seizure freedom than lamotrigine ( P  < 0.05).
Conclusions –  The results indicate that, in SCE, seizures can be controlled with carefully selected CT more commonly than suggested by previous studies. The seizure prognosis of patients with IGE presenting to a specialist in epilepsy may be worse than previously thought.     

Epilepsy surgery in the first 3 years of life: A Canadian survey

Objective:   To determine the clinical characteristics, surgical challenges, and outcome in children younger than 3 years of age undergoing epilepsy surgery in Canada.
Methods:   Retrospective data on patients younger than age 3 years who underwent epilepsy surgery at multiple centers across Canada from January 1987 to September 2005 were collected and analyzed.
Results:   There were 116 patients from eight centers. Seizure onset was in the first year of life in 82%, and mean age at first surgery was 15.8 months (1–35 months). Second surgeries were done in 27 patients, and a third surgery in 6. Etiologies were malformations of cortical development (57), tumor (22), Sturge-Weber syndrome (19), infarct (8), and other (10). Surgeries comprised 40 hemispheric operations, 33 cortical resections, 35 lesionectomies, 7 temporal lobectomies, and one callosotomy. There was one surgical mortality. The most common surgical complications (151 operations in 116 patients) were infection (17) and aseptic meningitis in 13. Of 107 patients with seizure outcome assessed more than one year postoperatively, 72 (67.3%) were seizure free (Engel I), 15(14%) had >90% improvement (Engel II), 12 had >50% improvement (Engel III), and 8 did not benefit from surgery (Engel IV). Development improved in 55.3% after surgery.
Conclusion:   Epilepsy surgery in children younger than 3 years of age is relatively safe and is effective in controlling seizures. Very young age is not a contraindication to surgery in children with refractory epilepsy, and early surgery may impact development positively.     

The effect of surgery in encephalopathy with electrical status epilepticus during sleep

Purpose: We analyzed clinical and electroencephalography (EEG) outcomes of 13 patients with pharmacoresistant encephalopathy with electrical status epilepticus during sleep (ESES) following epilepsy surgery. Methods: All patients had symptomatic etiology of ESES and preoperative neuropsychological deterioration. Ten patients had daily atypical absences. Clinical outcome was assessed at 6 months and at 2 years after surgery. Clinical and EEG data were reviewed retrospectively. The spike propagation pattern and area and source strength in source montage were analyzed from preoperative and postoperative EEG studies. Key Findings: Preoperative sleep EEG showed electrical status epilepticus during sleep (SES) with one‐way interhemispheric propagation in nine patients and with two‐way interhemispheric propagation in four. The age of the patients at the time of surgery ranged from 3.6–9.9 years. Focal resection (two patients) or hemispherotomy (one patient with postoperative EEG) either terminated SES or restricted the discharge to one region. Either reduced SES propagation area or source strength was found in four of eight callosotomy patients with postoperative EEG. Of patients who had seizures preoperatively, Engel class I–II seizure outcome was observed in two of three children after focal resection or hemispherotomy and in two of eight children after callosotomy. None of these patients with Engel class I–II outcome had SES with two‐way interhemispheric propagation on preoperative EEG. Cognitive deterioration was halted postoperatively in all except one patient. Cognitive catch‐up of more than 10 IQ points was seen in three patients, all of whom had shown a first measured IQ of >75. Significance: Patients with pharmacoresistant ESES based on symptomatic etiology may benefit from resective surgery or corpus callosotomy regarding both seizure outcome and cognitive prognosis.     

Epileptic networks in focal cortical dysplasia revealed using electroencephalography-functional magnetic resonance imaging

Objective:

Surgical treatment of focal epilepsy in patients with focal cortical dysplasia (FCD) is most successful if all epileptogenic tissue is resected. This may not be evident on structural magnetic resonance imaging (MRI), so intracranial electroencephalography (icEEG) is needed to delineate the seizure onset zone (SOZ). EEG‐functional MRI (fMRI) can reveal interictal discharge (IED)‐related hemodynamic changes in the irritative zone (IZ). We assessed the value of EEG‐fMRI in patients with FCD‐associated focal epilepsy by examining the relationship between IED‐related hemodynamic changes, icEEG findings, and postoperative outcome.

Methods:

Twenty‐three patients with FCD‐associated focal epilepsy undergoing presurgical evaluation including icEEG underwent simultaneous EEG‐fMRI at 3T. IED‐related hemodynamic changes were modeled, and results were overlaid on coregistered T1‐weighted MRI scans fused with computed tomography scans showing the intracranial electrodes. IED‐related hemodynamic changes were compared with the SOZ on icEEG and postoperative outcome at 1 year.

Results:

Twelve of 23 patients had IEDs during recording, and 11 of 12 had significant IED‐related hemodynamic changes. The fMRI results were concordant with the SOZ in 5 of 11 patients, all of whom had a solitary SOZ on icEEG. Four of 5 had >50% reduction in seizure frequency following resective surgery. The remaining 6 of 11 patients had widespread or discordant regions of IED‐related fMRI signal change. Five of 6 had either a poor surgical outcome (<50% reduction in seizure frequency) or widespread SOZ precluding surgery.

Interpretation:

Comparison of EEG‐fMRI with icEEG suggests that EEG‐fMRI may provide useful additional information about the SOZ in FCD. Widely distributed discordant regions of IED‐related hemodynamic change appear to be associated with a widespread SOZ and poor postsurgical outcome. ANN NEUROL 2011     

Neuropsychological Findings: Myoclonic Astatic Epilepsy (MAE) and Lennox-Gastaut Syndrome (LGS)

Summary:  Purpose: To identify a specific neuropsychological profile associated with myoclonic astatic epilepsy (MAE) and Lennox-Gastaut syndrome (LGS).
Methods: Seven patients diagnosed with MAE and four patients diagnosed with LGS were selected from patients referred to our Child Neurology Unit. The patients were assessed both clinically (awake, sleep, Holter EEG, seizures frequency, and semiology) and neuropsychologically (IQ, language, attention, visuospatial and visuomotor abilities, and behavior). One representative case of each syndrome is presented here.
Results: The clinical picture of the MAE patient resembled that of an MAE condition associated with transitory epileptic encephalopathy. The neuropsychological findings suggest that electroclinical anomalies can temporarily affect cognitive and behavioral functioning. Early effective antiepileptic drug (AED) treatment was found to improve cognitive outcome. In contrast, LGS was associated with mental retardation, which persisted after seizure control.
Conclusions: At present, it remains difficult to delineate a precise neuropsychological profile associated with MAE and LGS. The cognitive outcome of MAE is variable and depends on the clinical pattern. With regard to LGS, the hypothesis of a genetic predisposition underlying both the epilepsy and the mental retardation is still valid. Alternatively, exposure to subclinical electrophysiological anomalies during a critical period of cerebral development may be responsible for the mental retardation. At the time the clinical manifestations appear, drug treatment, even if effective, would have only limited impact on cognitive outcome. However, early multidisciplinary intervention may help to improve behavior and communicative abilities, enhancing the quality of life of these children and their families.     

Predictors of seizure outcome in newly diagnosed partial epilepsy: memory performance as a prognostic factor.

The epilepsy patients whose seizures will prove to be refractory should be identified as early as possible, and thus the need for new prognostic factors of intractable epilepsy is evident. The aim of the study was to investigate predictors of seizure outcome in a multivariate analysis. Neurological, electroencephalography (EEG) and neuropsychological variables were analyzed as potential predictors of epilepsy. Eighty-nine newly diagnosed adult patients with partial epilepsy were, after a prospective 2-year follow-up period, categorized into one of the two groups: patients with satisfactorily controlled epilepsy, and patients with refractory epilepsy. Six variables predicted 2-year seizure outcome: presence of spike focus in EEG, partial complex or mixed seizure type, remote symptomatic etiology, moderately impaired memory performance in immediate recall and in delayed recognition of the word list, and age at the time of diagnosis. The correct seizure outcome could be predicted with the model in 94% of newly diagnosed epilepsy patients. The presence of verbal memory impairment at the time of the diagnosis of partial epilepsy is a significant predictor of seizure outcome and, together with clinical and EEG variables, it predicts seizure outcome in the majority of the patients. Memory performance as a prognostic factor is of most value in patients with risk of refractory epilepsy and when used in a multidisciplinary setting.     

儿童难治性颞叶癫痫的手术治疗

目的 探讨儿童难治性颞叶癫痫术前评估和手术方法 及影响癫痫预后的因素.方法 回顾性分析2007年7月至2009年2月手术治疗的21例儿童难治性癫痫患者中得到随访的19例临床资料,主要为复杂部分性发作.多数患者有腹部不适等发作先兆和咂嘴等发作时伴随自动动作.MRI扫描15例异常.6例行PET扫描均异常.头皮脑电图示局灶痫性放电7例,多灶痫性放电12例.施行一侧颞前叶+海马、杏仁核切除术15例,一侧颞前叶、海马、杏仁核+部分额叶皮层切除术4例.结果 随访12-30个月,癫痫发作结果 ,Engel Ⅰ级13例;Ⅱ级3例;Ⅲ级1例;Ⅳ级2例.随访期间对4例进行神经心理学评估,2例明显好于术前.无永久性神经缺损并发症.术后切除标本病理诊断结果 为颞叶皮层发育不良和颞叶内侧硬化等.结论 颞叶切除治疗儿童难治性癫痫多数预后良好.该手术安全、并发症少.发作表现、EEG以及神经影像学检查对致痫灶定位相互符合时,预示预后良好.早期手术可能对患儿的神经心理学改善有帮助.