Differences between mesial and neocortical magnetic-resonance-imaging-negative temporal lobe epilepsy.

OBJECTIVE: The aim of this study was to assess clinical and electrophysiological differences within a group of patients with magnetic-resonance-imaging-negative temporal lobe epilepsy (MRI-negative TLE) according to seizure onset zone (SOZ) localization in invasive EEG (IEEG). METHODS: According to SOZ localization in IEEG, 20 patients with MRI-negative TLE were divided into either having mesial SOZ-mesial MRI-negative TLE or neocortical SOZ-neocortical MRI-negative TLE. We evaluated for differences between these groups in demographic data, localization of interictal epileptiform discharges (IEDs), and the ictal onset pattern in semiinvasive EEG and in ictal semiology. RESULTS: Thirteen of the 20 patients (65%) had mesial MRI-negative TLE and 7 of the 20 patients (35%) had neocortical MRI-negative TLE. The differences between mesial MRI-negative TLE and neocortical MRI-negative TLE were identified in the distribution of IEDs and in the ictal onset pattern in semiinvasive EEG. The patients with neocortical MRI-negative TLE tended to have more IEDs localized outside the anterotemporal region (p=0.031) and more seizures without clear lateralization of ictal activity (p=0.044). No other differences regarding demographic data, seizure semiology, surgical outcome, or histopathological findings were found. CONCLUSIONS: According to the localization of the SOZ, MRI-negative TLE had two subgroups: mesial MRI-negative TLE and neocortical MRI-negative TLE. The groups could be partially distinguished by an analysis of their noninvasive data (distribution of IEDs and lateralization of ictal activity). This differentiation might have an impact on the surgical approach.

Long-term outcomes in patients after epilepsy surgery failure.

PURPOSE: The primary aim of this study was to analyze the long-term outcomes of patients who were classified as Engel IV one year after resective epilepsy surgery. The secondary objectives were to evaluate the effectiveness of different treatment options and to examine the reasons that the patients did not undergo resective reoperation. METHODS: Our study was designed as a retrospective open-label investigation of the long-term outcomes of 34 patients (12% of all surgically treated patients) who were classified as Engel IV one year after epilepsy surgery. RESULTS: At the last follow-up visit (average of 7.6 ± 4.2 years after surgery), 12 of the 34 examined patients (35.3%) were still classified as Engel IV; 22 of the 34 patients (64.7%) were improved (Engel I-III). Of the 34 patients, 8 (23.5%) achieved an excellent outcome, classified as Engel I, 3 patients (8.8%) were classified as Engel II, and 11 patients (32.4%) as Engel III. The seizure outcome in the patients classified as Engel I was achieved by resective reoperation in 4; by a change in antiepileptic medication in 3 patients; and by vagus nerve stimulation (VNS) in 1 patient. The seizure outcome of Engel II was achieved by a change in antiepileptic medication in all 3 patients. Of the 34 patients, a total of 6 (17.6%) underwent resective reoperation only. The major reasons for this were the absence of a plausible hypothesis for invasive re-evaluation, the risk of postoperative deficit, and multifocal epilepsy in the rest of patients. CONCLUSION: Although the reoperation rate was relatively low in our series, we can achieve better or even excellent seizure outcomes using other procedures in patients for whom resective surgery initially failed.

Ictal and postictal semiology in patients with bilateral temporal lobe epilepsy.

Bilateral temporal lobe epilepsy is characterized by evidence of seizure onset independently in both temporal lobes. The main aim of the present study was to determine whether patients with evidence of independent bilateral temporal lobe epilepsy (biTLE) can be identified noninvasively on the basis of seizure semiology analysis. Thirteen patients with biTLE, as defined by invasive EEG, were matched with 13 patients with unilateral temporal lobe epilepsy (uniTLE). In all 26 patients, the frequency of predefined clusters of ictal and periictal signs were evaluated: ictal motor signs (IMSs), periictal motor signs (PIMSs), periictal vegetative signs (PIVSs), the frequency of early oroalimentary automatisms (EOAs), and the duration of postictal unresponsiveness (PU). Some other noninvasive and clinical data were also evaluated. A lower frequency of IMSs was noted in the group with biTLE (patients = 46.2%, seizures = 20.7%) than in the group with uniTLE (patients = 92.3%, seizures = 61.0%) (p = 0.030; p < 0.001, respectively). The individual IMS average per seizure was significantly lower in the group with biTLE (0.14; range = 0-1.0) than in the group with uniTLE (0.80; range = 0-2.6) (p = 0.003). Postictal unresponsiveness was longer than 5 min in more patients (75.0%) and seizures (42.9%) in the group with biTLE than in the group with uniTLE (patients = 30.8%, seizures = 18.6%) (p = 0.047; p = 0.002). The frequency of EOAs, PIMSs, PIVSs, and other clinical data did not differ significantly. There is a lower frequency of ictal motor signs and longer duration of postictal unresponsiveness in patients with biTLE.

Effect of partial drug withdrawal on the lateralization of interictal epileptiform discharges and its relationship to surgical outcome in patients with hippocampal sclerosis.

OBJECTIVE: To assess changes in the relative lateralization of interictal epileptiform discharges (IEDs) and interictal EEG prognostic value in terms of surgical outcome between periods with full medication (FMP) and reduced medication (RMP) in patients with temporal lobe epilepsy (TLE) associated with hippocampal sclerosis (HS). METHODS: Interictal scalp EEGs of 43 patients were evaluated for the presence of IEDs separately in a waking state (WS) and sleeping state (SS) during FMP and RMP. In each period, patients were categorized as having unitemporal or bitemporal IEDs. Surgical outcome was classified at year 1 after surgery and at last follow-up visit as Engel I or Engel II-IV; and alternatively as completely seizure-free or not seizure-free. RESULTS: There were significant changes in relative IED lateralization between FMP and RMP during SS. The representation of patients with unitemporal IEDs declined from 37 (86%) in FMP during SS to 25 (58%) in RMP during SS (p=0.003). At year 1 after surgery, the relative IED lateralization is a predictive factor for surgical outcome defined as Engel I vs. Engel II-IV in both FMP during WS (p=0.037) and during SS (p=0.007), and for surgical outcome defined as completely seizure-free vs. not seizure-free in FMP during SS (p=0.042). At last follow up visit, the relative IED lateralization is a predictor for outcome defined as Engel I vs. Engel II-IV in FMP during SS (p=0.020), and for outcome defined as completely seizure-free vs. not seizure-free in both FMP during WS (p=0.043) and in FMP during SS (p=0.015). When stepwise logistic regression analysis was applied, only FMP during SS was found to be an independent predictor for surgical outcome at year 1 after surgery (completely seizure-free vs. not seizure-free p=0.032, Engel I vs. Engel II-IV p=0.006) and at last follow-up visit (completely seizure-free vs. not seizure-free p=0.024, Engel I vs. Engel II-IV p=0.017). Gender was found to be independent predictor for surgical efficacy at year 1 if the outcome was defined as completely seizure-free vs. not seizure-free (p=0.036). CONCLUSION: The predictive value of relative IED lateralization with respect to surgical outcome in interictal EEG is present only during FMP; the predictive value decreases with the reduction of AEDs caused by the change of relative IED lateralization.

Long-term seizure outcome in patients with juvenile absence epilepsy; a retrospective study in a tertiary referral center.

PURPOSE: The study aim was to evaluate pharmacotherapy effects and long-term seizure outcomes in patients with juvenile absence epilepsy (JAE) during a five-year follow-up period. The secondary aim was to identify factors from patient history and determine their influence on seizure control. METHOD: We retrospectively studied 46 patients with JAE in the period between 2006 and 2011. The age at seizure onset, onset seizure type, family history of epilepsy, status epilepticus in history, medication history, and the rate of seizure control were studied. RESULTS: There were 30 females (65.2%) and 16 males (34.8%) in the study. The mean age at seizure onset was 12.9±5.6 years (ranged from 3 to 28 years). In 30 patients (65.2%), seizure onset was with absences, in 15 patients (32.6%) with generalized tonic-clonic seizure (GTCS), and in 1 patient (2.2%) with absence status. In 43 patients (93.5%), GTCS occurred in the course of the disease. Family history for epilepsy was positive in 10 patients (21.7%). In the five-year follow-up period, seizure freedom (Group 1) was achieved in 7 patients (15.2%). In total, 22 patients (47.8%) were classified into the groups involving very poor seizure control and antiepileptic drug resistance (Groups 5 and 6). The mean number of antiepileptic drugs (AEDs) used in the course of the disease in appropriate therapeutic doses was 3.8±2.3 (1-10 AEDs). CONCLUSION: The study results show that almost half of JAE patients have poor seizure control with a high rate of pharmacoresistance. The outcome of JAE can be very uncertain.

Long-term outcome and predictors of resective surgery prognosis in patients with refractory extratemporal epilepsy.

PURPOSE: We analyzed the long-term postoperative outcome and possible predictive factors of the outcome in surgically treated patients with refractory extratemporal epilepsy. METHODS: We retrospectively analyzed 73 patients who had undergone resective surgery at the Epilepsy Center Brno between 1995 and 2010 and who had reached at least 1 year outcome after the surgery. The average age at surgery was 28.3±11.4 years. Magnetic resonance imaging (MRI) did not reveal any lesion in 24 patients (32.9%). Surgical outcome was assessed annually using Engel's modified classification until 5 years after surgery and at the latest follow-up visit. RESULTS: Following the surgery, Engel Class I outcome was found in 52.1% of patients after 1 year, in 55.0% after 5 years, and in 50.7% at the last follow-up visit (average 6.15±3.84 years). Of the patients who reached the 5-year follow-up visit (average of the last follow-up 9.23 years), 37.5% were classified as Engel IA at each follow-up visit. Tumorous etiology and lesions seen in preoperative MRI were associated with significantly better outcome (p=0.035; p<0.01). Postoperatively, 9.6% patients had permanent neurological deficits. CONCLUSION: Surgical treatment of refractory extratemporal epilepsy is an effective procedure. The presence of a visible MRI-detected lesion and tumorous etiology is associated with significantly better outcome than the absence of MRI-detected lesion or other etiology.

Rhythmic ictal nonclonic hand (RINCH) motions in temporal lobe epilepsy: invasive EEG findings, incidence, and lateralizing value.

The main purpose of this retrospective analysis was to evaluate the incidence and lateralization value of rhythmic ictal nonclonic hand (RINCH) motions in patients with temporal lobe epilepsy (TLE), who were classified as Engel I at least 2 years after epilepsy surgery. We analyzed the distribution of ictal activity at the time of RINCH appearance in patients in whom RINCH motions were present during invasive EEG monitoring. A group of 120 patients was included in this study. In total, we reviewed 491 seizures: 277 seizures in patients with temporal lobe epilepsy (TLE) associated with hippocampal sclerosis (TLE-HS group) and 214 in TLE caused by other lesions (TLE-OTH group). We analyzed 29 patients (79 of the seizures) during invasive EEG monitoring. Fisher's exact test and binomial test were used for the statistical analysis. RINCH motions were observed in 24 out of 120 patients (20%) and in 48 out of 491 seizures (9.8%). There was no significant difference between the occurrence of RINCH motions in patients with TLE-HS and in patients with TLE-OTH, or between gender, right/left-sided TLE, and language dominant/nondominant TLE. RINCH motions were contralateral to the seizure onset in 83.3% of patients and 91.7% of seizures (p=0.0015; p<0.001, respectively). There were no differences in the lateralizing value of RINCH motions in patients with TLE-HS or TLE-OTH. We analyzed RINCH motions in 5 patients/7 seizures during invasive EEG. In all 7 seizures with RINCH motions, we observed the widespread activation of the temporal lobe (mesial and lateral, opercular and polar regions) contralateral to the side of RINCH motions. In all 7 seizures, we observed that at the time of RINCH motion onset, at least 1 explored region of the frontal lobe was affected by the ictal activity. In 3 seizures, we observed time-locked epileptic activation associated with the appearance of RINCH motions, i.e., in the orbitofrontal cortex in 2 seizures and in both the orbitofrontal cortex and anterior cingulate gyrus in 1 seizure. RINCH motions are a relatively frequent ictal sign in patients with TLE. They have a high lateralizing value in these patients, occurring contralateral to the ictal onset. RINCH motions usually occur after the spread of ictal activity beyond the temporal lobe, and their appearance is usually associated with the presence of ictal activity in various regions of the contralateral frontal lobe, mainly the orbitofrontal cortex and anterior cingulate gyrus. This is the first study analysing this phenomenon during invasive EEG recording.

Comparing the effects of cortical resection and vagus nerve stimulation in patients with nonlesional extratemporal epilepsy.

The main purpose of this retrospective study was to compare the effects of resective surgery (RESgr-26 patients) and vagus nerve stimulation (VNSgr-35 patients) on seizure frequency (2 and 5years after surgery) in patients with nonlesional extratemporal epilepsy (NLexTLE). We analyzed hospital admission costs directly associated with epilepsy (HACE) in both groups at the same follow-up. The decrease in seizure frequency from the preoperative levels, in both VNSgr and RESgr, was statistically significant (p<0.001). The seizure frequency reduction did not differ significantly between the follow-up visits for either group (p=0.221 at 2years and 0.218 at 5years). A significantly higher number of Engel I and Engel I+II patients were found in RESgr than in VNSgr at both follow-up visits (p=0.04 and 0.007, respectively). Using McHugh classification, we did not find statistically significant differences between both groups at both follow-up visits. Hospital admission costs directly associated with epilepsy/patient/year in both RESgr and VNSgr dropped significantly at 2- and 5-year follow-up visit and this reduction was not statistically different between RESgr and VNSgr (p=0.232). Both VNS and resective surgery cause comparably significant seizure reduction in NLexTLE. Resective surgery leads to a greater number of patients with excellent postoperative outcome (Engel I+II). The HACE reduction is statistically comparable between both groups.

Syncope with atypical trunk convulsions in a patient with malignant arrhythmia.

Syncope is a condition often misdiagnosed as epilepsy. Syncope caused by cardiac disturbance is a life-threatening condition and accurate diagnosis is crucial for patient outcome. We present a case study of a 71-year-old woman who was referred to our epilepsy centre with a diagnosis of refractory epilepsy. We diagnosed convulsive syncope caused by malignant cardiac arrhythmia based on the presence of cardiac asystole lasting for 20-30 seconds, which was caused by sick sinus syndrome combined with third-degree atrioventricular block. The most prominent feature of this syncope was atypical trunk (abdominal or thoracoabdominal) convulsions, which were accompanied by other motor signs (head and eye deviation and brief jerks of the extremities). In the periods between attacks, all investigations, including standard 12-lead ECG and 24-hour ECG monitoring, were normal. This case study highlights the challenge in differential diagnosis of sudden loss of consciousness. [Published with video sequences].

Intracerebrally recorded high frequency oscillations: simple visual assessment versus automated detection.

OBJECTIVE: We compared the possible contribution (in the detection of seizure onset zone - SOZ) of simple visual assessment of intracerebrally recorded high-frequency oscillations (HFO) with standard automated detection. METHODS: We analyzed stereo-EEG (SEEG) recordings from 20 patients with medically intractable partial seizures (10 temporal/10 extratemporal). Independently using simple visual assessment and automated detection of HFO, we identified the depth electrode contacts with maximum occurrences of ripples (R) and fast ripples (FR). The SOZ was determined by independent visual identification in standard SEEG recordings, and the congruence of results from visual versus automated HFO detection was compared. RESULTS: Automated detection of HFO correctly identified the SOZ in 14 (R)/10 (FR) out of 20 subjects; a simple visual assessment of SEEG recordings in the appropriate frequency ranges correctly identified the SOZ in 13 (R)/9 (FR) subjects. CONCLUSIONS: Simple visual assessment of SEEG traces and standard automated detection of HFO seem to contribute comparably to the identification of the SOZ in patients with focal epilepsies. When using macroelectrodes in neocortical extratemporal epilepsies, the SOZ might be better determined by the ripple range. SIGNIFICANCE: Standard automated detection of HFO enables the evaluation of HFO characteristics in whole data. This detection allows general purpose and objective evaluation, without any bias from the neurophysiologist's experiences and practice.

Intracranial EEG seizure onset patterns in unilateral temporal lobe epilepsy and their relationship to other variables.

OBJECTIVE: We performed a retrospective study to determine the different types of seizure onset patterns (SOP) in invasive EEG (IEEG) in patients with temporal lobe epilepsy (TLE). METHODS: We analyzed a group of 51 patients (158 seizures) with TLE who underwent IEEG. We analyzed the dominant frequency during the first 3s after the onset of ictal activity. The cut-off value for distinguishing between fast and slow frequencies was 8 Hz. We defined three types of SOPs: (1) fast ictal activity (FIA) - frequency ≥8 Hz; (2) slow ictal activity (SIA) - frequency <8 Hz; and (3) attenuation of background activity (AT) - no clear-cut rhythmic activity during the first 3s associated with changes of IEEG signal (increase of frequency, decrease of amplitude). We tried to find the relationship between different SOP types and surgery outcome, histopathological findings, and SOZ localization. RESULTS: The most frequent SOP was FIA, which was present in 67% of patients. More patients with FIA were classified postoperatively as Engel I than those with SIA and AT (85% vs. 31% vs. 0) (P < 0.001). There were no statistically significant differences in the type of SOP, in the histopathological findings, or in the SOZ localization. CONCLUSION: In patients with refractory TLE, seizure onset frequencies ≥8 Hz during the first 3s of ictal activity are associated with a better surgical outcome than frequencies <8 Hz. SIGNIFICANCE: Our study suggests that very early seizure onset frequencies in IEEG in patients with TLE could be the independent predictive factor for their outcome, regardless of the localization and etiology.

Do the basal ganglia inhibit seizure activity in temporal lobe epilepsy?

There is substantial evidence in the literature that the basal ganglia (BG), namely the striatum and pallidum, are involved in temporal lobe epilepsy (TLE). The BG are probably not involved in elaborating clinical seizures, as they do not produce specific epileptiform activity and there is no evident change in the electrical activity in the BG immediately after seizure onset. The data we obtained by direct ictal recording in the BG [1,2], as well as a large body of experimental and clinical evidence reported by other groups, suggest an inhibitory role of the BG during temporal lobe seizures. The BG may have a remote influence on cortical oscillatory processes related to control of epileptic seizures via their feedback pathways to the cortex.

Grey-white matter abnormalities in temporal lobe epilepsy associated with hippocampal sclerosis: Inter-observer analysis, histopathological findings, and correlation with clinical variables.

This study was conducted to determine the incidence of grey-white matter abnormalities (GWMAs) on magnetic resonance images (MRIs) in patients with hippocampal sclerosis (HS), to assess the inter-observer reliability of this finding, and to establish a possible relationship between GWMA and histopathological findings in the anterior part of the temporal lobe, as well as its other relation to clinical variables. We established a group of 55 patients with histologically proven HS. Three observers independently reviewed the MRIs to assess whether GWMA was present. Substantial independent inter-observer agreement was reached for 44 of the 55 patients (80%) (Fleiss' kappa 0.732; p<0.0001). GWMAs were present in 38% of patients (HS+GWMA). Focal cortical dysplasia (FCD) of type IIIa (ILAE classification) was present in 31% of patients. FCD type IIIa was present in 52.4% with HS+GWMA, and in 17.6% without GWMA (HS-GWMA) (p=0.007). We did not find any statistically significant differences in the postoperative outcomes between HS+GWMA and HS-GWMA. We did not find any statistically significant differences in the presence or absence of GWMA and FCD of the temporal pole in relation to the onset of epilepsy, the duration of epilepsy, or the presence of potential epileptogenic insults. GWMA in the anterior part of temporal lobe in patients with HS is a reliable assessment sign for observers who are experienced in evaluating the MRIs of epilepsy patients. The presence of GWMA is significantly associated with the presence of FCD type IIIa in these patients. The presence or absence of GWMA and FCD type IIIa does not influence the postoperative outcome of HS patients.

The role of voxel-based morphometry in the detection of cortical dysplasia within the temporal pole in patients with intractable mesial temporal lobe epilepsy.

PURPOSE: To determine whether voxel-based morphometry (VBM) might contribute to the detection of cortical dysplasia within the temporal pole in patients with mesial temporal lobe epilepsy and hippocampal sclerosis (MTLE/HS). METHODS: Eighteen patients with intractable MTLE/HS and 30 sex- and age-matched healthy controls were included in the study. All of the patients fulfilled the diagnostic criteria for MTLE/HS and underwent anteromedial temporal resection. VBM without a modulation step was applied to the magnetic resonance (MR) images of the brain. Statistical parametric maps were used to compare structural characteristics such as gray matter concentration (GMC) within the temporal pole among patients and controls separately. The acquired data were then statistically analyzed to determine the congruency between visually inspected MR imaging (MRI) scans and VBM results in the detection of morphologic abnormalities in the temporal pole compared to postoperative histopathologic findings of cortical dysplasia. KEY FINDINGS: Histopathologic examination revealed cortical dysplasia within the temporal pole in 11 patients. In detail, according to Palmini's classification, mild malformations of cortical development (mMCDs) were disclosed in three patients, focal cortical dysplasia (FCD) type Ia in three patients, and FCD type Ib in five patients. Some type of structural temporal pole abnormality was suggested by VBM in 14 patients and by visually inspected MRI scans in 11 patients. The results of VBM were in agreement with the presence/absence of cortical dysplasia in 13 patients (72.2%); this correspondence was significant (p = 0.047). In one case, VBM was false negative and in four cases it was false positive. There was congruence between the results of visual analysis and histologic proof in 55.6% of examined patients, which was not significant. SIGNIFICANCE: We found that VBM made a superior contribution to the detection of temporopolar structural malformations (cortical dysplasia) compared to visual inspection. The agreement with postoperative histopathologic proof was clearly significant for VBM results and nonsignificant for visual inspection.

Postictal psychosis and its electrophysiological correlates in invasive EEG: a case report study and literature review.

We identified two patients with medically refractory temporal lobe epilepsy, from whom intracranial EEG recordings were obtained at the time of postictal psychosis. Both patients had mesial temporal epilepsy associated with hippocampal sclerosis. In both patients, the postictal psychosis was associated with a continual "epileptiform" EEG pattern that differed from their interictal and ictal EEG findings (rhythmical slow wave and "abortive" spike-slow wave complex activity in the right hippocampus and lateral temporal cortex in case 1 and a periodic pattern of triphasic waves in the contacts recording activity from the left anterior cingulate gyrus). Some cases of postictal psychosis might be caused by the transient impairment of several limbic system structures due to the "continual epileptiform discharge" in some brain regions. Case 2 is the first report of a patient with TLE in whom psychotic symptoms were associated with the epileptiform impairment of the anterior cingulate gyrus.

"MRI-negative PET-positive" temporal lobe epilepsy: invasive EEG findings, histopathology, and postoperative outcomes.

The aim of this retrospective study was to analyze invasive EEG findings, histopathology, and postoperative outcomes in patients with MRI-negative, PET-positive temporal lobe epilepsy (TLE) (MRI-/PET+TLE) who had undergone epilepsy surgery. We identified 20 patients with MRI-/PET+TLE (8.4% of all patients with TLE who had undergone surgery; 11 men, 9 women). Of the 20 patients, 16 underwent invasive EEG. The temporal pole and hippocampus were involved in the seizure onset zone in 62.5% of the patients. We did not identify a lateral temporal or extratemporal seizure onset in any patient. Of the 20 patients, 17 had follow-up periods >1 year (mean follow-up=3.3 years). At the final follow-up, 70.6% patients were classified as Engel I, 5.8% of patients as Engel II, and 11.8% of patients as Engel III and IV (11.8%). Histopathological evaluation showed no structural pathology in any resected hippocampus in 58% of all evaluated temporal poles. The most common pathology of the temporal pole was focal cortical dysplasia type IA or IB. MRI-/PET+TLE should be delineated from other "nonlesional TLE." The ictal onset in these patients was in each case in the temporal pole or hippocampus, rather than in the lateral temporal neocortex. Standard surgery produced a good postoperative outcome, comparable to that for patients with lesional TLE. Histopathological findings were limited: the most common pathology was focal cortical dysplasia type I.

Depression as a prominent cause of sexual dysfunction in women with epilepsy.

The etiology of sexual dysfunction in patients with epilepsy is perceived as multifactorial, with seizure and medication effects being the most often discussed and analyzed factors. We used common statistical methods to evaluate the impact of type of epilepsy, antiepileptic medication, hormones, seizure control, and symptoms of depression and anxiety on sexual function in a group of 78 women with epilepsy. To assess sexual function, we used the Female Sexual Function Index (FSFI). To assess symptoms of depression and anxiety, we used the Beck Depression and Anxiety Inventories (BDI, BAI). Of all the observed factors, only BDI score was significantly correlated with FSFI score. There was no correlation between FSFI, hormonal levels, seizure frequency, and symptoms of anxiety. No differences were found between patients with focal and those with generalized epilepsies; between seizure-free and non-seizure-free patients; or in relation to the number and type of antiepileptic medications.

Ictal and peri-ictal oscillations in the human basal ganglia in temporal lobe epilepsy.

Preictal, ictal, and postictal oscillations in the basal ganglia were analyzed. Five persons with temporal lobe epilepsy who were candidates for surgery had diagonal depth electrodes implanted in the basal ganglia: four of them in the putamen, and one in the pallidum and caudate. Time-frequency and power spectral analyses were used to analyze the EEG. Significant frequency components of 2-10 Hz were consistently observed in the basal ganglia. The frequency of this component slowed during seizures. There was a significant ictal increase in power spectral density in all frequency ranges. The changes in the basal ganglia were consistent while seizure activity spread over the cortex, and partially persisted after the clinical seizure ended. They were inconsistent in the period after seizure onset. Seizures originating in the mesiotemporal structures can affect physiological rhythms in the basal ganglia. The basal ganglia did not generate epileptiform EEG activity. An inhibitory role for the basal ganglia during temporal lobe seizures is suggested.

Peri-ictal yawning lateralizes the seizure onset zone to the nondominant hemisphere in patients with temporal lobe epilepsy.

The main aim of this retrospective study was to investigate the incidence and lateralizing value of peri-ictal yawning in patients with temporal lobe epilepsy (TLE) who underwent successful surgery for epilepsy (Engel class I outcome at the 2-year follow-up visit). We reviewed a total of 97 patients (59 men and 38 women). Fifty-three patients had TLE arising from the nondominant temporal lobe, and 44 had TLE arising from the dominant temporal lobe. In total, we reviewed 380 seizures. Of those, 202 seizures arose from the nondominant temporal lobe and 178 from the dominant one. Peri-ictal yawning was observed in 4 of 97 patients (4.1%) and in 7 of 380 seizures (1.8%), in the postictal period in all cases. Peri-ictal yawning occurred only in patients with right-sided, nondominant TLE. It may have a lateralizing value.

Effect of chronic vagal nerve stimulation on interictal epileptiform discharges.

We evaluated the effect of vagus nerve stimulation (VNS) on interictal epileptiform discharges (IEDs) in 32 epileptic patients (18 females; 14 males) with an average age of 42.2+/-11.4 years, all of whom had been suffering from epilepsy for an average of 29.2+/-14.5 years. All of the patients had received VNS for 5 years. The first EEG was performed prior to the initiation of stimulation; the second EEG was performed at the 5-year follow-up visit. The duration of each EEG was 30 min. We compared these two EEGs in terms of the number of IEDs present in each patient and correlated them to other variables. The average total number of IEDs during EEG and the total number of seconds in which IEDs were present decreased significantly after 5 years of stimulation from 97.3+/-106.9 resp. 80.6+/-86.1 to 49.4+/-94.0 resp. 37.8+/-65.0. Although there was no positive correlation between the reduction of IEDs and the percent of seizure reduction, we found a greater decrease of IEDs in patients who responded to VNS in comparison to those who did not. The decrease of IEDs was more pronounced in patients suffering from temporal lobe epilepsy than in patients suffering from extratemporal epilepsy. No other significant correlations were found. VNS reduced IEDs in patients chronically simulated for epilepsy. The reduction of IEDs was greater in patients who responded to VNS and in patients suffering from temporal lobe epilepsy.