Correlation of language lateralization with resting state hippocampal connectivity in temporal lobe epilepsy patients

Background/aim: The main purpose of this study is to evaluate the resting state hippocampal connectivity with language areas and to correlate them with laterality index calculations on single subject basis, hence to present hippocampal lateralization for language with rs-fMRI. Materials and methods: Task based and rs-fMRI data were gathered from a total of 45 subjects in 3T scanner. BrainVoyager QX, SPM, and CONN softwares were used for data analysis. LI score of each subject was calculated and converted into normalized LI score (nLI). Intrahemispheric rs-connectivity analysis was performed between hippocampus and Broca's regions on both sides. Correlation between these variables was measured with SPSS software. Results: Right-TLE patients were found to have highest whereas left-TLE group were found to have lowest mean LI scores. Regarding hippocampal-lingual networks; left intrahemispheric connectivity values showed strong positive correlation with nLI values in left, right-TLE patients and healthy controls (P = 0.035, 0.014, 0.047). There were no significant correlation between right intrahemispheric connectivity values and nLI scores in all groups. Conclusions: This study seems to depict the existence of resting state hippocampal-lingual functional network which correlates well with lateralization of language function in the left hemisphere in both temporal lobe epilepsy patients and healthy controls.

Evaluation of brain FDG PET images in temporal lobe epilepsy for lateralization of epileptogenic focus using data mining methods

Background/aim: In temporal lobe epilepsy (TLE), brain positron emission tomography (PET) performed with F-18 fluorodeoxyglucose (FDG) is commonly used for lateralization of the epileptogenic temporal lobe. In this study, we aimed to evaluate the success of quantitative analysis of brain FDG PET images using data mining methods in the lateralization of the epileptogenic temporal lobe. Materials and methods: Presurgical interictal brain FDG PET images of 49 adult mesial TLE patients with a minimum of 2 years of postsurgical follow-up and Engel I outcomes were retrospectively analyzed. Asymmetry indices were calculated from PET images from the mesial temporal lobe and its contiguous structures. The J48 and the logistic model tree (LMT) data mining algorithms were used to find classification rules for the lateralization of the epileptogenic temporal lobe. The classification results obtained by these rules were compared with the physicians' visual readings and the findings of single-patient statistical parametric mapping (SPM) analyses in a test set of 18 patients. An additional 5-fold cross-validation was applied to the data to overcome the limitation of a relatively small sample size. Results: In the lateralization of 18 patients in the test set, J48 and LMT methods were successful in 16 (89%) and 17 (94%) patients, respectively. The visual consensus readings were correct in all patients and SPM results were correct in 16 patients. The 5-fold cross- validation method resulted in a mean correct lateralization ratio of 96% (47/49) for the LMT algorithm. This ratio was 88% (43 / 49) for the J48 algorithm. Conclusion: Lateralization of the epileptogenic temporal lobe with data mining methods using regional metabolic asymmetry values obtained from interictal brain FDG PET images in mesial TLE patients is highly accurate. The application of data mining can contribute to the reader in the process of visual evaluation of FDG PET images of the brain.

Effects of vagus nerve stimulation on heart rate variability in children with epilepsy.

PURPOSE: The aim of this study was to evaluate the effects of vagus nerve stimulation (VNS) on heart rate variability (HRV) in children with epilepsy. METHODS: The subgroups of HRV, namely time domain (Standard deviation of NN interval (SDNN), SDNN index, Standard deviation of the averages of NN intervals (SDANN), Root mean square of successive differences (RMMSD), Adjacent NN intervals differing by more than 50 ms in the entire recording divided by the total number of all NN intervals (PNN50), triangular index) and frequency domain (Low-frequency (LF), High-frequency (HF), LF/HF), were investigated in 20 pediatric patients before and after 6 and 12months of VNS treatment during day and night by comparing their data with those of 20 control subjects. In addition, subgroups of age, epilepsy duration and localization, and antiepileptic drugs (AEDs) were also evaluated if they had further effects on basal HRV levels. RESULTS: Increased heart rates (HRs); decreased SDNN, SDANN, RMMSD, and PNN50; and increased LF/HF ratios were identified before VNS therapy (p<0.05). Even though remarkable improvement was seen after 6months of VNS treatment (p<0.05), no further changes were observed in 12-month compared with 6-month levels (p>0.05) in all parameters, still even significantly lower than those of controls (p<0.05). Longer duration of epilepsy and localization of epileptic focus, such as in the temporal lobe, were also found to further contribute to diminished basal HRV levels (p<0.05). CONCLUSION: The cardiovascular system is under deep sympathetic influence in children with epilepsy. Although VNS seems to provide a substantial improvement by achieving increased parasympathetic effects in short-term therapy, the levels were still lower than those of healthy children after either short- or long-term therapy. Therefore, impaired cardiovascular autonomic regulation may be associated with the epileptic process itself as well as with the contribution of some additional factors. Overall, different aspects such as age, epilepsy duration, epileptic focus, seizure frequency, and AEDs should also be considered for their further possible effects on HRV during VNS therapy.

Comparison of ILAE 2010 and semiological seizure classification in children with epilepsy.

OBJECTIVE: The aim of this study was to compare both ILAE 2010 and semiological seizure classification (SSC) in terms of their applicability and utility and to predict epileptogenic zone in children with epilepsy. METHODS: Both ILAE 2010 classification and SSC which is a part of five dimensional classification were applied for a total 138 children by dividing into younger (≤6y/o) and older (>6y/o) age groups over the last two years as retrospectively. After the assessment of the seizures types, epilepsy syndromes, and etiologies; the data were also compared to evaluate if having correlation between epileptogenic zone and seizure subtypes in both ILAE 2010 and SSC. RESULTS: ILAE 2010 indicated that 66.7% of the patients had focal seizures, 15.9% had generalized seizures, and 14.4% had seizures of unknown origin. The SSC revealed that the most frequent seizure type was simple seizures (56.5%), second frequent one was complex motor seizures (46.4%) and dialeptic seizures (39.9%). To predict epileptogenic zone, SSC was found to be more specific than ILAE in terms of the more subgroups of SSC were related to the more subgroups of epileptogenic zone (p<0.05). Furthermore, there was a clear correlation between focal foci and specific seizure types in older ages, while many foci caused to same seizure types and tend to no clear focal foci with generalized onset in younger ages. On the other hand, the relationship between epileptogenic zone and etiology was more remarkable in the five dimensional classification. SIGNIFICANCE: Preference of seizure classification system is unique for each patient and depends on requirements. Therefore, one dimension cannot be sufficient for evaluation the nature of the seizures in some patients. Furthermore, age related evolution of the seizure types should not be ignored due to ongoing maturation state of the brain. ILAE 2010 and SSC have weak and strong points compared to each other. Semiological seizure classification is more informative in terms of identifying the epileptogenic zone which may be important in specific occasions like pre-surgical work up, while ILAE is simple and easier method which can be applied for seizure description and their characteristics in daily practice.

Comparative Lateralizing Ability of Multimodality MRI in Temporal Lobe Epilepsy.

Purpose. The objective is to compare lateralizing ability of three quantitative MR (qMRI) modalities to depict changes of hippocampal architecture with clinical entities in temporal lobe epilepsy. Methods. We evaluated 14 patients with clinical and EEG proven diagnosis of unilateral TLE and 15 healthy volunteers. T1-weighted 3D dataset for volumetry, single-voxel 1H MR spectroscopy (MRS), and diffusion tensor imaging (DTI) were performed for bilateral hippocampi of all subjects. Results. Individual volumetric measurements provided accurate lateralization in 85% of the patients, spectroscopy in 57%, and DTI in 57%. Higher lateralization ratios were acquired combining volumetry-spectroscopy (85%), spectroscopy-DTI (85%), and volumetry-DTI (100%). Significantly decreased NAA/(Cho+Cr) ratios (p = 0.002) and increased FA (p = 0.001) values were obtained in ipsilateral to epileptogenic hippocampus. Duration of epilepsy and FA values showed a significant negative correlation (p = 0.016, r = -0.847). The history of febrile convulsion associated with ipsilateral increased ADC values (p = 0.015, r = 0.851) and reduced NAA/(Cho+Cr) ratios (p = 0.047, r = -761). Conclusion. Volumetry, MRS, and DTI studies provide complementary information of hippocampal pathology. For lateralization of epileptogenic focus and preoperative examination, volumetry-DTI combination may be indicative of diagnostic accuracy.

Ictal kissing: Electroclinical features of an unusual ictal phenomenon.

PURPOSE: The study aimed to describe the electroclinical features of ictal kissing, an unusual behavior that may occur during focal seizures. METHOD: Twenty-five patients collected from four epilepsy centers and previously published reports were reviewed for their demographic, clinical, and electrophysiological features. RESULTS: Sixteen of 25 patients were female. The mean age was 32.9 years (9.9-51 years) and the average age at seizure onset was 14.5 years. All seizures were localized to the temporal lobe (TL) and lateralized to right side in 17 patients, left side in 2 patients, and unclear in 6 patients. A total of 55 ictal video electroencephalograms (EEGs) were analyzed. There were other symptoms such as speaking, spitting, hugging, and oral and upper-extremity automatisms along with different types of ictal kissing behavior during the seizures. The median duration of all seizures was 106.7±73.73s. Kissing occurred at a median time of 71s (1-95s) after the onset of seizure, and ictal epileptiform discharges usually involved TL during kissing episode. CONCLUSION: Ictal kissing is mainly associated with right TL and female gender, although association with left TL may also occurs, possibly related to the circuits involving temporo-insular structures.

Outcomes of resective surgery in children and adolescents with focal lesional epilepsy: The experience of a tertiary epilepsy center.

OBJECTIVE: This study aimed to investigate the efficacy of resective surgery in children with focal lesional epilepsy by evaluating the predictive value of pre- and postsurgical factors in terms of seizure freedom. METHODS: This study included 61 children aged between 2 and 18years who were admitted to the pediatric video-EEG unit for presurgical workup. Each patient was evaluated with a detailed history, video-EEG, neuroimaging, and postsurgical outcomes according to Engel classification to predict postsurgical seizure freedom. All the possible factors including history, etiology, presurgical evaluation, surgical procedures, and postsurgical results were analyzed for their predictive value for postoperative seizure freedom. RESULTS: Of the 61 patients, 75% were diagnosed as having temporal lobe epilepsy (TLE), and 25% were diagnosed with extra-TLE. Two years after the surgery, 78.6% were seizure-free, of which 89% had TLE, and 50% had extra-TLE (p<0.05). Patients were more likely to have a favorable outcome for seizure freedom if they had rare seizure frequency, focal EEG findings, and focal seizures; had a temporal epileptogenic zone; or had TLE and hippocampal sclerosis. On the other hand, patients were more likely to have unfavorable results for seizure freedom if they had younger age of seizure onset, frequent seizures before the surgery, a frontal or multilobar epileptogenic zone, secondarily generalized seizures, extra-TLE with frontal lobe surgery, or focal cortical dysplasia. SIGNIFICANCE: Resective surgery is one of the most effective treatment methods in children with intractable epilepsy. A history of young age of seizure onset, frequent seizures before surgery, secondarily generalized seizures, a multilobar epileptogenic zone, frontal lobe surgery, and focal cortical dysplasia (FCD) are the most important predictive factors indicating that a patient would continue having seizures after surgery. On the other hand, focal seizure semiologies, temporal lobe localization, and hippocampal sclerosis indicate that a patient would have better results in terms of seizure freedom.

Sleep-wake distribution and circadian patterns of epileptic seizures in children.

BACKGROUND: Epilepsy is one of the most common chronic neurologic disorders. Daily periodicity of epileptic seizures has been known for over a century. The diurnal patterns of epileptic seizures have also been observed in studies. AIM: To investigate the sleep/wake cycle, day/night, and 24-h periodicity of various seizure subtypes and seizure onset localizations in children. METHODS: We analyzed the clinical seizures of 170 consecutive epilepsy patients who underwent video-electroencephalography (EEG) monitoring over the last 5 years. Semiology of the seizures was classified according to the semiological seizure classification. Origin of the seizures was defined by the onset of ictal activity on EEG. Seizures were evaluated in terms of occurrence during the day (06:00-18:00 h) or night (18:00-06:00 h), in wakefulness or in sleep, and within a 3-h time interval throughout 24 h. RESULTS: A total of 909 seizures were analyzed. Auras, dialeptic, myoclonic, hypomotor, atonic seizures, and epileptic spasms occurred more frequently in wakefulness; tonic, clonic, and hypermotor seizures occurred more frequently in sleep. Auras, dialeptic, and atonic seizures and epileptic spasms occurred more often during daytime; hypermotor seizures occurred more often at night. Generalized seizures were seen most frequently in wakefulness (between 12:00 and 18:00 h); frontal lobe seizures were seen at night and in sleep (between 24:00 and 03:00 h); temporal lobe seizures were seen in wakefulness (between 06:00 and 09:00 h and between 12:00 and 15:00 h); occipital seizures were seen during daytime and in wakefulness (between 09:00 and 12:00 h and between 15:00 and 18:00 h, respectively); parietal seizures were seen mostly during daytime. CONCLUSIONS: Seizures in children occur in specific circadian patterns and in specific sleep/wake distributions depending on seizure onset location and semiology.

Long term effect of vagus nerve stimulation in pediatric intractable epilepsy: an extended follow-up.

PURPOSE: Over the past two decades, vagus nerve stimulation (VNS) has become an accepted and viable treatment modality for intractable epilepsy both in children and adults. Earlier studies have demonstrated short-term seizure outcomes, usually for up to 5 years; so far, none have reported an extended outcome in children. We aimed to assess long term seizure outcome in children with intractable epilepsy for more than 5 years. METHODS: We identified patients who had VNS implantation for treatment of intractable epilepsy from March 2000 to March 2015 at our Epilepsy Center and collected data including demographic, age at epilepsy onset and VNS implantation, duration of epilepsy, seizure type, number of antiepilepsy drugs (AEDs), and monthly seizure frequency before VNS implantation and at the last clinic visit. Phone surveys were conducted with patients without recent clinic follow-up. RESULTS: Fifty-six patients (aged 4-17 at the time of implant) are the subjects of the study. Seizure reduction of >50 % was achieved in 9.8 % (6th month), 24 % (2nd year), 46.4 % (3rd year), and 54 %(5th year), and overall 35 (62.5 %) of the 56 subjects had a greater than 50 % reduction in seizure frequency at the last follow-up. Eleven patients became seizure free. The results, once obtained, were maintained steadily or even improved over time without any loss of efficacy during the follow-up. The only parameter, significantly related with clinical response, was age at seizure onset. The most frequent adverse events were hoarseness, cough, sore throat, and anorexia, experienced by 13 patients. Two patients had local wound infections and lead to the removal of the stimulator. An improvement in alertness, attention, and psychomotor activity, independent of the efficacy of vagal nerve stimulation, was observed in 8 patients. CONCLUSION: To our knowledge, this is the first pediatric study evaluating seizure outcome over more than 5 years of follow-up, and demonstrates a favorable seizure outcome of >50 % seizure frequency in 62.5 % of patients and seizure freedom in 11 patients. It is well tolerated over an extended period of time.

Surgical outcome in patients with MRI-negative, PET-positive temporal lobe epilepsy.

PURPOSE: The purpose of this study was to determine the long-term surgical outcomes of magnetic resonance imaging (MRI)-negative, fluorodeoxyglucose positron emission tomography (FDG-PET)-positive patients with temporal lobe epilepsy (TLE) and compare them with those of patients with mesial temporal sclerosis (MTS). METHODS: One hundred forty-one patients with TLE who underwent anterior temporal lobectomy were included in the study. The surgical outcomes of 24 patients with unilateral temporal hypometabolism on FDG-PET without an epileptogenic lesion on MRI were compared with that of patients with unilateral temporal hypometabolism on FDG-PET with MTS on MRI (n=117). The outcomes were compared using Engel's classification at 2 years after surgery. Clinical characteristics, unilateral interictal epileptiform discharges (IEDs), histopathological data and operation side were considered as probable prognostic factors. RESULTS: Class I surgical outcomes were similar in MRI-negative patients and the patients with MTS on MRI (seizure-free rate at postoperative 2 years was 79.2% and 82% in the MRI-negative and MTS groups, respectively). In univariate analysis, history of febrile convulsions, presence of unilateral IEDs and left temporal localization were found to be significantly associated with seizure free outcome. Multivariate analysis revealed that independent predictors of a good outcome were history of febrile convulsions and presence of unilateral IEDs. CONCLUSION: Our results suggest that epilepsy surgery outcomes of MRI-negative, PET positive patients are similar to those of patients with MTS. This finding may aid in the selection of best candidates for epilepsy surgery.

An evaluation of lateralizing signs in patients with temporal lobe epilepsy.

Resective epilepsy surgery has been accepted as an effective treatment for patients with medically intractable temporal lobe epilepsy (TLE) to control the seizures and to limit cognitive dysfunction. Complete resection of the epileptic zone, and therefore the success of the surgery, depends on the identification of the seizure focus. Reliable lateralizing semiologic signs, together with other presurgical assessments, are of great importance for an accurate identification of the seizure focus. In this respect, this study evaluated the frequency of semiologic signs in medically intractable temporal lobe epilepsy (TLE) together with the lateralizing values and variations according to the age and gender groups. Two hundred seventy-three seizures of 55 patients of the Adult Epilepsy Monitoring Unit of Gazi University Faculty of Medicine with the diagnosis of medically intractable TLE, whose epileptic foci were detected through noninvasive presurgical procedures and seizures were controlled successfully after anterior temporal lobectomy (ATL), were analyzed retrospectively. Seizure semiologies of the patients were evaluated in terms of lateralizing values, and it was inquired whether age/gender causes any variation. Versive head rotation, unilateral dystonic limb posturing, asymmetric tonic limb posturing, and the combination of unilateral hand automatisms and dystonic posturing were determined as the semiologic signs with the highest lateralizing values (90-100%). While hand automatisms were observed frequently in the group with early seizure-onset age (onset age ≤ 2), asymmetric tonic limb posturing was detected as more frequent in the group with later seizure-onset age (onset age > 2; p < .005). In addition to this, semiologic signs were noted to be different between male and female groups; psychic and autonomic auras and ictal emotional signs were associated with women (p < .005).

Presurgical evaluation of mesial temporal lobe epilepsy with multiple advanced MR techniques at 3T.

BACKGROUND AND PURPOSE: Accurate localization of the epileptogenic zone is essential for successful surgical treatment of mesial temporal lobe epilepsy (MTLE). The aim of this study was to analyze and compare the hippocampal volumetry (HV), MR spectroscopy (MRS), Dynamic susceptibility contrast (DSC) and pulsed arterial spin labeling (pASL) perfusion techniques in a large sample size of refractory MTLE patients. MATERIALS AND METHODS: Forty-two patients with medically refractory MTLE who underwent preoperative evaluation and eleven normal controls were studied. Pathologic and control hippocampi were compared in terms of hippocampal volume, metabolite ratios and relative hippocampal perfusion values. By using cut-off points and asymmetry indexes, percentages of performance indicators for each technique were calculated in groups of MR (+), MR (-) and bilateral MTLE. RESULTS: For all techniques, a statistically significant difference was found between the pathologic and control hippocampus groups (P<0.001). Also, all of them except HV had diagnostic value in groups of MR (-) and bilateral MTLE. CONCLUSION: HV, MRS, DSC and pASL have achieved comparable performance and each of them provides important information about the lateralization of epileptogenic focus. Among those, pASL and MRS may easily be used as an adjunct to conventional MR.

Ictal body turning in focal epilepsy.

Despite the explanations of many lateralization findings, body turning in focal epilepsy has been rarely investigated. One of the aims of this study was to evaluate the role of ictal body turning in the lateralization of focal epilepsies. The records of 263 patients with focal epilepsy (temporal lobe epilepsy (TLE), n=178; extratemporal lobe epilepsy (ETLE), n=85) who underwent prolonged video-EEG monitoring during presurgical epilepsy evaluation were reviewed. Preoperative findings (TLE, n=16; ETLE, n=6) and postoperative outcomes (TLE, n=7) of patients with focal epilepsy with ictal body turning were assessed. For the evaluation of ictal body turning, two definitions were proposed. Nonversive body turning (NVBT) was used to denote at least a 90° nonforced (without tonic or clonic component) rotation of the upper (shoulder) and lower (hip) parts of the body around the body axis for a minimum of 3s. Versive body turning (VBT) was used to denote at least a 90° forced (with tonic or clonic component) rotation of the upper (shoulder) and lower (hip) parts of the body around the body axis for a minimum of 3s. Nonversive body turning was observed in 6% (n=11) of patients with TLE and 2% (n=2) of patients with ETLE. For VBT, these ratios were 5% (n=8) and 7% (n=6) for patients with TLE and ETLE, respectively. Nonversive body turning was frequently oriented to the same side as the epileptogenic zone (EZ) in TLE and ETLE seizures (76% and 80%, respectively). If the amount of NVBT was greater than 180°, then it was 80% to the same side in TLE seizures. Versive body turning was observed in 86% of the TLE seizures, and 55% of the ETLE seizures were found to be contralateral to the EZ. When present with head turning, NVBT ipsilateral to the EZ and VBT contralateral to the EZ were more valuable for lateralization. In TLE seizures, a significant correlation was found between the head turning and body turning onsets and durations. Our study demonstrated that ictal body turning is a rarely observed but reliable lateralization finding in TLE and ETLE seizures, which also probably has the same pathophysiological mechanism as head turning in TLE seizures.

pASL versus DSC perfusion MRI in lateralizing temporal lobe epilepsy.

BACKGROUND: Accurate lateralization of the epileptogenic focus in temporal lobe epilepsy (TLE) is crucial. Pulsed arterial spin labeling (pASL) has the capability of quantifying local relative cerebral blood flow (rCBF) by measuring the inflow of electromagnetically labeled arterial blood into the target area, and can be used in the presurgical workup of refractory TLE. PURPOSE: To evaluate pASL in detecting mesial temporal lobe (mTL) perfusion asymmetry for the lateralization of the epileptogenic focus in patients with refractory TLE and to compare it with dynamic susceptibility contrast enhanced (DSC) magnetic resonance imaging (MRI) technique. MATERIAL AND METHODS: This study was approved by the local ethical committee, and written informed consent was obtained in each patient. Thirty-six patients with medically refractory TLE and 11 healthy volunteer was enrolled in this study. Following brain MRI, pASL and DSC perfusion were performed in all subjects at 3T. rCBF measurements with two different perfusion MRI technique were compared between the patient and healthy volunteers. Lateralization based on perfusion asymmetry index (AI) were also evaluated and compared with clinical lateralization. RESULTS: rCBF ratios measured in healthy volunteers by two different perfusion technique did not show any statistically significant difference. In TLE patients rCBF ratio of the ipsilateral (affected) side was found to be significantly lower than the contralateral (unaffected) side with both technique. The AI in the patient group was 8.86 ± 3.88 with pASL and 8.39 ± 4.06 with DSC. Correlation coefficient between clinical laterality and perfusion AI were 0.86 for pASL and 0.83 for DSC. CONCLUSION: pASL can successfully detect interictal asymmetry in patients with TLE and can readily be combined with routine structural assessment for lateralization, providing an alternative to DSC perfusion.

Surgery for intractable temporal lobe epilepsy: experience of a single institution.

BACKGROUND/AIM: In the treatment of epilepsy, encouraging results have been achieved with surgical treatment, especially for temporal lobe epilepsy (TLE). Drug resistance must be diagnosed as early as possible, because the ensuing seizures can be eliminated surgically via temporal lobe surgery in a high percentage (70%-90%) of patients. In this study we share our experience, in a single institution, of surgical treatment of intractable TLE. MATERIALS AND METHODS: Between March 2006 and November 2010 we performed 127 corticoamygdalohippocampectomy (CAH) procedures. All CAH surgical procedures were done as described by Niemeyer's technique. Resection lengths were 4-4.5 cm from the temporal pole. RESULTS: At the end of 24 months, 79.7% (n = 94) patients were still on antiepileptic medications, with 55 of them on a decreased number or dose of drugs, and 20.3 (n = 24) patients were antiepileptic drug-free. Postoperative Engel's classes were 1, 2, and 3 in 87.2%, 5.08%, and 7.6%, respectively. There was no mortality in follow-up, and dysphasia in 1 patient (0.84%) was the only morbidity. CONCLUSION: In our series we found that the outcome of surgery is associated with careful patient selection, which requires a detailed investigation of the patients. Our final conclusion is that outcome scores are independent of age, pathology, or sex but are dependent on correct patient selection.

Successful surgical treatment of medically refractory epilepsy after chemotherapy in a child with leukemia: a case report.

INTRODUCTION: Mesial temporal sclerosis associated with acute lymphoblastic leukemia has been rarely reported. CASE REPORT: We report a case of a 15-year-old boy with acute lymphoblastic leukemia who developed medically refractory temporal lobe epilepsy in a long time period after chemotherapy, and successfully treated with surgical resection. CONCLUSIONS: To our knowledge, this is the first description of a leukemic child with medically refractory temporal lobe epilepsy who achieved seizure-freedom postoperatively during the long-term follow-up. The clinical history and details of the underlying pathophysiological background and treatment of this complication are discussed in this case report.

The efficacy of vagal nerve stimulation in children with pharmacoresistant epilepsy: practical experience at a Turkish tertiary referral center.

BACKGROUND: Vagus nerve stimulation (VNS) is an effective therapy for pharmacoresistant epilepsy. Nevertheless, information regarding the long-term outcome of VNS in children is limited. AIM: To describe the long-term outcome of VNS in patients with pharmacoresistant epilepsy treated at the Gazi University Medical Faculty Epilepsy Center, Turkey. PATIENTS AND METHODS: The study included 24 patients - all younger than 18 years of age (mean age: 14.31 years). Median age at the time of VNS device implantation was 11 years. Median age at onset of epilepsy was 21 months and median duration of epilepsy was 126 months. All the patients' seizures were intractable with antiepileptic drug treatment and all had been treated with an average of 6+/-2 antiepileptic medications. In all, 12 patients had secondary generalized seizures and 12 had partial seizures. Because this was a retrospective open study, the number of seizures could not be enumerated in most of these cases. RESULTS: The only factor that was associated with seizure reduction was duration of follow-up. Age at seizure onset and age at VNS device implantation were not associated with seizure reduction. The difference in seizure reduction between patients >12 years of age and patients <12 years of age was not significant. Mean percentage of seizure reduction after 6 months-7 years of treatment was, respectively, 22.5% (n=24) (6th month), 32% (n=20) (1st year), 42% (n=16) (2nd year), 50.45% (n=11) (3rd year), 52% (n=10) (4th year), 60% (n=8) (5th year), 61.25% (n=8) (6th year), and 61.6% (n=6) (7th year). The positive effect of VNS persisted throughout the follow-up period. CONCLUSIONS: Although it is an expensive method, VNS is an effective treatment method. This series shows the necessity of long-term follow-up series for understanding the efficacy and advantages of VNS. Prospective, long-term double-blind studies with large samples are needed to confirm the present study's findings.

Inhibitory effect of valproic acid on cytochrome P450 2C9 activity in epilepsy patients.

Drug interactions constitute a major problem in the treatment of epilepsy because drug combinations are so common. Valproic acid is a widely used anticonvulsant drug with a broad therapeutic spectrum. Case reports suggest interaction between valproic acid and other drugs metabolized mainly by cytochrome P450 isoforms. The aim of this study was to evaluate the inhibitory effect of valproic acid on cytochrome P450 2C9 (CYP2C9) activity by using losartan oxidation as a probe in epilepsy patients. Patients were prescribed sodium valproate (mean 200 mg/day for the first week and 400 mg/day in the following period) according to their clinical need. A single oral dose of 25 mg losartan was given to patients before and after the first dose, first week and 4 weeks of valproic acid treatment. Losartan and E3174, the CYP2C9-derived carboxylic acid metabolite of losartan in 8 hr urine were assayed by using high pressure liquid chromatography. Urinary losartan/E3174 ratio did not change significantly on the first day (0.9, 0.3-3.5; median, range), and first week (0.6, 0.2-3.8; median, range), while a significant increase was observed after 4 weeks of valproic acid treatment (1.1, 0.3-5.7; median, range) as compared to that of measured before valproic acid administration (0.6, 0.1-2.1; median, range) (P = 0.039). The degree of inhibition was correlated with the steady-state plasma concentrations of valproic acid (r(2) = 0.70, P = 0.04). The results suggest an inhibitory effect of valproic acid on CYP2C9 enzyme activity in epilepsy patients at steady state. The risk of pharmacokinetic drug-drug interactions should be taken into account during concomitant use of valproic acid and CYP2C9 substrates.

Semiological seizure classification: before and after video-EEG monitoring of seizures.

The study objective was to assess the applicability and reliability of the semiological seizure classification in children with epilepsy in outpatient clinics. Ninety patients (age range, 2-16 years) who experienced clinical seizures during prolonged video-electroencephalogram (EEG) monitoring were evaluated. Semiological seizure classification was performed, first based on history obtained from parents of the patient during outpatient follow-up visits and then based on video EEG-monitoring. Kappa statistics (kappa) were used to evaluate the consistency of the two rounds of semiological seizure classification. Classification based on history yielded the following distribution: simple motor seizures (66.3%), aura (28%), complex motor seizures (15.8%), special seizures (15.8%), dialeptic seizures (9.3%), and autonomic seizures (3.7%). Classification based on video EEG-monitoring yielded a different distribution: simple motor seizures (55.7%), complex motor seizures (26.9%), automotor seizures (26.9%), aura (23%), dialeptic seizures (22.1%), special seizures (9.6%), and autonomic seizures (1.9%). Negative myoclonic seizures (kappa = 1, P = 0.000) and hypermotor seizures (kappa = 0.85, P = 0.000) had excellent consistency; somatosensory aura (kappa = 0.26, P = 0.012) and automotor seizures (kappa = 0.28, P = 0.004) had the lowest consistency. The families or doctors often defined simple motor seizures (decrease of 10.6% from before to after monitoring, kappa = 0.44); the proportion of complex motor seizures changed rather from before to after monitoring (11.1%, kappa = 0.33). Generally, parents can describe seizures quite well. We suggest that semiological seizure classification is a reliable method applicable for everyday use during outpatient visits, especially if seizure semiology is evaluated individually for each component or if the semiological seizure classification is modified or refined for some seizure components (tonic, clonic, versive, conscious, automotor seizures).

Reoperation of a recurrent temporal lobe epilepsy: a technical case report.

BACKGROUND: The indications for the reoperation of a recurrent temporal lobe epilepsy, the risks, and outcome have not been well documented. The invasive video electroencephalogram (EEG) monitoring and magnetic resonance imaging (MRI) techniques can reveal the residual tissues and their epileptogenic activity so that a reoperation decision can be made. CASE DESCRIPTION: A 30-year-old patient who had recurrent temporal lobe epilepsy and had undergone 2 operations at the same temporal region is presented. After both of these operations, approximately 6 months later, seizures relapsed. Postoperative neuroimaging studies showed residual mesiotemporal tissues at the operative site. The invasive video EEG monitoring revealed epileptogenic activity originating from these residual tissues. After all of these investigations, it was thought that a third operation was indicated, and the patient was operated. Postoperative course was uneventful. No postoperative deficit was observed. Pathological examination was reported as hippocampal sclerosis. He is seizure-free at his third postoperative year. CONCLUSIONS: Complete resection of epileptogenic mesiotemporal structures at the first operation can prevent the necessity for reoperation in defined cases. The MRI and invasive video EEG monitoring techniques can reveal the residual tissues and their epileptogenic activity in a recurrent epilepsy case.