Semiological seizure classification

Mesial temporal lobe epilepsy with no specific histological abnormality: a distinct surgically remediable syndrome

PURPOSE

The purposes of the study were twofold: to clarify the clinical features and surgical outcome of mesial temporal lobe epilepsy (MTLE) with no specific histological abnormality and to determine the optimal surgical strategy.

METHODS

Twelve patients who met the following criteria were included: (1) normal preoperative MRI; (2) intracranial EEG findings consistent with mesial temporal onset of seizures; (3) selective amygdalohippocampectomy (AHE) was performed, and the patient was followed for more than 2years postoperatively; and (4) hippocampal histopathology was nonspecific. Clinical characteristics, intracranial EEG findings, and postoperative seizure outcome were examined. These twelve patients were compared with twenty-one patients with MTLE with unilateral hippocampal sclerosis (HS) on MRI who underwent intracranial EEG before resection (control group).

RESULTS

In patients with MTLE with no specific histological abnormality, the age at onset was significantly higher, the history of febrile seizures was significantly less frequent, and preoperative IQ score was significantly higher than that in the control group. The proportion of patients with bitemporal independent and/or nonlateralizing seizure onset on intracranial EEG was 50% in patients with MTLE with nonspecific histopathology and was significantly higher than that in the control group. Seizure outcome was classified as Engel class I in seven patients, class II in three, class III in one, and class IV in one. Seizure outcome was favorable even in three patients with seizures originating more frequently from the side contralateral to the resected side.

CONCLUSIONS

Mesial temporal lobe epilepsy with no specific histological abnormality is a clinical entity distinctly different from MTLE with HS. Bitemporal independent and/or nonlateralizing seizure onset on intracranial EEG is very common. Although the presence of lateral temporal and/or extratemporal epileptogenicity should always be kept in mind, postoperative seizure outcome after AHE is favorable even in cases with bitemporal independent and/or nonlateralizing seizure onset.

Cingulate epilepsy: report of 3 electroclinical subtypes with surgical outcomes

IMPORTANCE

The literature on cingulate gyrus epilepsy in the magnetic resonance imaging era is limited to case reports and small case series. To our knowledge, this is the largest study of surgically confirmed epilepsy arising from the anterior or posterior cingulate region.

OBJECTIVE

To characterize the clinical and electrophysiological findings of epilepsies arising from the anterior and posterior cingulate gyrus.

DESIGN, SETTING, AND PARTICIPANTS

We studied consecutive cingulate gyrus epilepsy cases identified retrospectively from the Cleveland Clinic and University of Texas Southwestern Medical Center epilepsy databases from 1992 to 2009. Participants included 14 consecutive cases of cingulate gyrus epilepsies confirmed by restricted magnetic resonance image lesions and seizure freedom or marked improvement following lesionectomy.

MAIN OUTCOMES AND MEASURES

The main outcome measure was improvement in seizure frequency following surgery. The clinical, video electroencephalography, neuroimaging, pathology, and surgical outcome data were reviewed.

RESULTS

All 14 patients had cingulate epilepsy confirmed by restricted magnetic resonance image lesions and seizure freedom or marked improvement following lesionectomy. They were divided into 3 groups based on anatomical location of the lesion and corresponding seizure semiology. In the posterior cingulate group, all 4 patients had electroclinical findings suggestive of temporal origin of the epilepsy. The anterior cingulate cases were divided into a typical (Bancaud) group (6 cases with hypermotor seizures and infrequent generalization with the presence of fear, laughter, or severe interictal personality changes) and an atypical group (4 cases presenting with simple motor seizures and a tendency for more frequent generalization and less-favorable long-term surgical outcome). All atypical cases were associated with an underlying infiltrative astrocytoma.

CONCLUSIONS AND RELEVANCE

Posterior cingulate gyrus epilepsy may present with electroclinical findings that are suggestive of temporal lobe epilepsy and can be considered as another example of pseudotemporal epilepsies. The electroclinical presentation and surgical outcome of lesional anterior cingulate epilepsy is possibly influenced by the underlying pathology. This study highlights the difficulty in localizing seizures arising from the cingulate gyrus in the absence of a magnetic resonance image lesion.

Neuroimaging characteristics of MRI-negative orbitofrontal epilepsy with focus on voxel-based morphometric MRI postprocessing

PURPOSE

The orbitofrontal (OF) region is one of the least explored regions of the cerebral cortex. There are few studies on patients with electrophysiologically and surgically confirmed OF epilepsy and a negative magnetic resonance imaging (MRI) study. We aimed to examine the neuroimaging characteristics of MRI-negative OF epilepsy with the focus on a voxel-based morphometric MRI postprocessing technique.

METHODS

We included six patients with OF epilepsy, who met the following criteria: surgical resection of the OF lobe with/without adjacent cortex, seizure-free for ≥12 months, invasive video-electroencephalography (EEG) monitoring showing ictal onset from the OF area, and preoperative MRI regarded as negative. Patients were investigated in terms of their image postprocessing and functional neuroimaging characteristics, electroclinical characteristics obtained from noninvasive and invasive evaluations, and surgical pathology. MRI postprocessing on T1 -weighted high-resolution scans was implemented with a morphometric analysis program (MAP) in MATLAB.

KEY FINDINGS

Single MAP+ abnormalities were found in four patients; three were in the OF region and one in the ipsilateral mesial frontal area. These abnormalities were included in the resection. One patient had bilateral MAP+ abnormalities in the OF region, with the ipsilateral one completely removed. The MAP+ foci were concordant with invasive electrophysiologic data in the majority of MAP+ patients (four of five). The localization value of 18F-fluorodeoxyglucose-positron emission tomography (FDG-PET) and ictal single-photon emission computed tomography (SPECT) is low in this cohort. Surgical pathology included focal cortical dysplasia, remote infarct, Rosenthal fiber formation and gliosis.

SIGNIFICANCE

Our study highlights the importance of MRI postprocessing in the process of presurgical evaluation of patients with suspected orbitofrontal epilepsy and "normal" MRI. Using MAP, we were able to positively identify subtle focal abnormalities in the majority of the patients. MAP results need to be interpreted in the context of their electroclinical findings and can provide valuable targets in the process of planning invasive evaluation.

Increased metalloprotease activity in the epileptogenic lesion--Lobectomy reduces metalloprotease activity and urokinase-type uPAR circulating levels

Inflammation influences the pathogenesis of seizures by boosting neuronal degeneration of temporal lobe epilepsy with hippocampal sclerosis (TLE-HS). This work aimed to determine the activity of metalloproteases (MMPs) in brain tissue fragments of TLE-HS patients and the effect of lobectomy on circulating inflammatory biomarkers. Surgical fragments (n=4) from epileptogenic focus (EF) e perilesion area (PL), and control hippocampus from autopsy (n=5) were processed for glial protein (GFAP), activated microglia (IB4) immunohistochemistry, and metalloprotease activity (MMP-2, -9). Perilesional area showed GFAP positive cells with morphology of activate astrocyte and reactive gliosis nearby the lesion. In the lesion foci, astrocytes had altered cytoarchitecture with disorganized stroma suggestive of necrosis, and numerous mononuclear cells with few projections and morphological characteristics of activate microglia. Analysis of MMP-9 and MMP-2 in the sera before and after hippocampectomy confirmed the inflammatory pattern of TLE-HS, with high MMP-9 activity; high MMP-9/TIMP-1 and urokinase uPAR plasma levels before lobectomy but low after surgery. Maintenance of MMP-2 activity indicates persistent tissue remodeling in both groups. The present work shows that patients with chronic and medically intractable TLE-HS that undergone amigdalo-hippocampectomy for removal of epileptogenic lesion had a clinical enduring benefit of lack seizure recurrence for up to a year, and consistent reduction of proteases (MMP-9 and uPAR) activation that participate as important inflammatory epileptogenic inducers.

Asymmetry of planum temporale constrains interhemispheric language plasticity in children with focal epilepsy

Reorganization of eloquent cortex enables rescue of language functions in patients who sustain brain injury. Individuals with left-sided, early-onset focal epilepsy often show atypical (i.e. bilateral or right-sided) language dominance. Surprisingly, many patients fail to show such interhemispheric shift of language despite having major epileptogenic lesions in close proximity to eloquent cortex. Although a number of epilepsy-related factors may promote interhemispheric plasticity, it has remained unexplored if neuroanatomical asymmetries linked to human language dominance modify the likelihood of atypical lateralization. Here we examined the asymmetry of the planum temporale, one of the most striking asymmetries in the human brain, in relation to language lateralization in children with left-sided focal epilepsy. Language functional magnetic resonance imaging was performed in 51 children with focal epilepsy and left-sided lesions and 36 healthy control subjects. We examined the association of language laterality with a range of potential clinical predictors and the asymmetry of the length of the planum temporale. Using voxel-based methods, we sought to determine the effect of lesion location (in the affected left hemisphere) and grey matter density (in the unaffected right hemisphere) on language laterality. Atypical language lateralization was observed in 19 patients (38%) and in four controls (11%). Language laterality was increasingly right-sided in patients who showed atypical handedness, a left perisylvian ictal electroencephalographic focus, and a lesion in left anterior superior temporal or inferior frontal regions. Most striking was the relationship between rightward asymmetry of the planum temporale and atypical language (R = 0.70, P < 0.0001); patients with a longer planum temporale in the right (unaffected) hemisphere were more likely to have atypical language dominance. Voxel-based regression analysis confirmed that increased grey matter density in the right temporo-parietal junction was correlated with right hemisphere lateralization of language. The length of the planum temporale in the right hemisphere was the main predictor of language lateralization in the epilepsy group, accounting for 48% of variance, with handedness accounting for only a further 5%. There was no correlation between language lateralization and planum temporale asymmetry in the control group. We conclude that asymmetry of the planum temporale may be unrelated to language lateralization in healthy individuals, but the size of the right, contra-lesional planum temporale region may reflect a ‘reserve capacity’ for interhemispheric language reorganization in the presence of a seizure focus and lesions within left perisylvian regions.

Hypermotor seizures in lateral and mesial parietal epilepsy

Four patients with refractory epilepsy and hypermotor seizures (HMS) benefited from an intracerebral investigation after a presurgical evaluation and demonstrated an ictal onset zone primarily involving the posterior cortex, specifically the posterior cingulate gyrus in two patients. At seizure onset, these two patients reported a falling sensation, followed by HMSs characterized by swinging movements of the trunk with intense grasping of the bed railing. The two other patients with lateral parietal seizure onset reported blurred vision and dizziness, followed by a mixed pattern of the previously described type 1 and 2 HMSs. Three patients have been operated on, including two class I of Engel after 36 and 52months of follow-up. One patient developed a postoperative infection and continues to suffer seizures. Pathological findings disclosed a type IIa focal cortical dysplasia in all the patients. The last patient is awaiting surgery. Posterior cortex epilepsies, including those originating from the posterior cingulate cortex, can be responsible for HMSs.

Clinical and ictal characteristics of infantile seizures: EEG correlation via long-term video EEG monitoring

PURPOSE

The semiology of infantile seizures often shows different characteristics from that of adults. We performed this study to describe clinical and ictal characteristics of infantile seizures at less than two years of age.

METHODS

A retrospective study was done for infants with epilepsy (ages: 1-24months) who underwent long-term video electroencephalography (EEG) monitoring at Samsung medical center between November 1994 and February 2012. We analyzed the clinical and ictal characteristics of the 56 cases from 51 patients.

RESULTS

In 69% of the patients, the seizure onset was before six months of age and the etiology was symptomatic in one third of the patients. Twelve seizure types were identified; spasms (24%), unilateral motor seizures (18%), and generalized tonic seizures (15%) were the three frequent types of seizure. All partial seizures were well correlated with the partial-onset ictal EEG, however 19.4% (7/36) of clinically generalized seizures revealed partial-onset ictal EEG. About one-thirds (4/11) of generalized tonic seizures had its ictal onset on unilateral or bilateral frontal areas and two out of seven generalized myoclonic seizures showed unilateral frontal rhythmic activities. Hypomotor seizures mainly arose from the temporal areas and hypermotor seizures from the frontal regions.

CONCLUSIONS

Even though most of the seizure semiology of infants is well correlated with ictal EEG, some of the generalized tonic seizures or myoclonic seizures revealed partial-onset ictal EEG suggesting localized epileptic focus. Accurate definition of seizures via video EEG monitoring is necessary for proper management of seizures in infancy, especially in some clinically generalized seizures.

Clinical events in psychogenic non-epileptic seizures based on semiological seizure classification

OBJECTIVES

None of the classifications of psychogenic non-epileptic seizures (PNES) have been widely accepted and used by physicians so far. In this study we aimed at classifying PNES on the basis of a modified version of semiological seizure classification (SSC). We also sought to assess the interrater reliability (IRR) of the PNES diagnosis based on SSC.

METHODS

We classified PNES into four types on the basis of our modification of SSC: pseudoaura, dialeptic, motor, and special (atonic, astatic, hypotonic) spells. Pseudoauras were not included in the statistical analysis. Ninety-one PNES attacks were observed during the 55 video-EEG sessions recorded for all patients. The interrater agreement was assessed by the kappa coefficient.

RESULTS

Twenty-nine women (78·3%) and eight men (21·6%) were surveyed, with a mean age of 28·4 ± 9·6 (range 16-54). The final diagnosis of PNES was established after a mean of 4·5 ± 2·3 years following the onset of PNES attacks in the patients. The mean seizure duration in the PNES was 241 seconds and 40·5% of our patients had PNES longer than 300 seconds. Motor and special PNES were the most common types observed by all the raters. The kappa values for each pair were as follows: Observers I-II 0·51 (p = 0·000), Observers I-III 0·47 (p = 0·000), and Observers II-III 0·73 (p = 0·000).

CONCLUSIONS

Interobserver agreement was moderate and substantial for three observers who classified PNES according to our modified SSC. The modified version of SSC could be used without difficulty in classifying PNES. Using SSC for PNES both shortens the period before diagnosis and eliminates the need to learn another new and acceptable classification for PNES.

Polymicrogyria-associated epilepsy: a multicenter phenotypic study from the Epilepsy Phenome/Genome Project

PURPOSE

Polymicrogyria (PMG) is an epileptogenic malformation of cortical development. We describe the clinical epilepsy and imaging features of a large cohort with PMG-related epilepsy.

METHODS

Participants were recruited through the Epilepsy Phenome/Genome Project, a multicenter collaborative effort to collect detailed phenotypic data on individuals with epilepsy. We reviewed phenotypic data from participants with epilepsy and PMG.

KEY FINDINGS

We identified 87 participants, 43 female and 44 male, with PMG and epilepsy. Median age of seizure onset was 3 years (range <1 month to 37 years). Most presented with focal epilepsy (87.4%), some in combination with seizures generalized from onset (23.0%). Focal seizures with dyscognitive features were most common (54.3%). Of those presenting with generalized seizure types, infantile spasms were most prevalent (45.2%). The most common topographic pattern was perisylvian PMG (77.0%), of which the majority was bilateral (56.7%). Generalized PMG presented with an earlier age of seizure onset (median age of 8 months) and an increased prevalence of developmental delay prior to seizure onset (57.1%). Of the unilateral, and asymmetric bilateral groups where PMG was more involved in one hemisphere, the majority (71.4%) of participants had seizures that lateralized to the same hemisphere as the PMG or the hemisphere with greater involvement.

SIGNIFICANCE

Participants with PMG had both focal and generalized onset of seizures. Our data confirm the involvement of known topographic patterns of PMG and suggest that more extensive distributions of PMG present with an earlier age of seizure onset and increased prevalence of developmental delay prior to seizure onset.

[Semiology and propagation of epileptic seizures]

The evaluation of episodic seizure-like symptoms is a common challenge in the neurologist's daily routine. The clinical signs (semiology) are the most important puzzle pieces to distinguish epileptic seizures from other episodic entities. Due to the often far-reaching health and social consequences of the diagnosis of epilepsy, the early and rigorous assessment of episodic symptoms by means of the patient history is important. This assessment is based on knowledge of the association of certain semiologies with epileptic syndromes and brain regions; however, certain limitations and pitfalls have to be considered. Typical propagation pathways of seizure activity determine the serial occurrence of semiological features and provide supplementary information.

Upper limb automatisms differ quantitatively in temporal and frontal lobe epilepsies

We quantitatively evaluated the localizing and lateralizing characteristics of ictal upper limb automatisms (ULAs) in patients with temporal lobe epilepsy (TLE; n=38) and frontal lobe epilepsy (FLE; n=20). Movement speed, extent, length, and duration of ULAs were quantitatively analyzed with motion capturing techniques. Upper limb automatisms had a larger extent (p<0.001), covered more distance (p<0.05), and were faster (p<0.001) in FLE than in TLE. In TLE, the maximum speed of ULAs was higher ipsilaterally than contralaterally (173 vs. 84pixels/s; p=0.02), with no significant difference in FLE (511 vs. 428). The duration of ictal automatisms in relation to the total seizure duration was shorter in TLE than in FLE (median 36% vs. 63%; p<0.001), with no difference in the absolute duration (26s vs. 27s). These results demonstrate that quantitative movement analysis of ULAs differentiates FLE from TLE, which may aid in the localization of the epileptogenic zone.

The epilepsies: complex challenges needing complex solutions

It is widely accepted that epilepsies are complex syndromes due to their multi-factorial origins and manifestations. Different mathematical and computational descriptions use appropriate methods to address nonlinear relationships, chaotic behaviors and emergent properties. These theoretical approaches can be divided into two major categories: descriptive, such as flowcharts, graphs and other statistical analyses, and explicative, which include both realistic and abstract models. Although these modeling tools have brought great advances, a common framework to guide their design, implementation and evaluation, with the goal of future integration, is still needed. In the current review, we discuss two examples of complexity analysis that can be performed with epilepsy data: behavioral sequences of temporal lobe seizures and alterations in an experimental cellular model. We also highlight the importance of the creation of model repositories for the epileptology field and encourage the development of mathematical descriptions of complex systems, together with more accurate simulation techniques.

Mapping preictal and ictal haemodynamic networks using video-electroencephalography and functional imaging

Ictal patterns on scalp-electroencephalography are often visible only after propagation, therefore rendering localization of the seizure onset zone challenging. We hypothesized that mapping haemodynamic changes before and during seizures using simultaneous video-electroencephalography and functional imaging will improve the localization of the seizure onset zone. Fifty-five patients with ≥2 refractory focal seizures/day, and who had undergone long-term video-electroencephalography monitoring were included in the study. 'Preictal' (30 s immediately preceding the electrographic seizure onset) and ictal phases, 'ictal-onset'; 'ictalestablished' and 'late ictal', were defined based on the evolution of the electrographic pattern and clinical semiology. The functional imaging data were analysed using statistical parametric mapping to map ictal phase-related haemodynamic changes consistent across seizures. The resulting haemodynamic maps were overlaid on co-registered anatomical scans, and the spatial concordance with the presumed and invasively defined seizure onset zone was determined. Twenty patients had typical seizures during functional imaging. Seizures were identified on video-electroencephalography in 15 of 20, on electroencephalography alone in two and on video alone in three patients. All patients showed significant ictal-related haemodynamic changes. In the six cases that underwent invasive evaluation, the ictal-onset phase-related maps had a degree of concordance with the presumed seizure onset zone for all patients. The most statistically significant haemodynamic cluster within the presumed seizure onset zone was between 1.1 and 3.5 cm from the invasively defined seizure onset zone, which was resected in two of three patients undergoing surgery (Class I post-surgical outcome) and was not resected in one patient (Class III post-surgical outcome). In the remaining 14 cases, the ictal-onset phase-related maps had a degree of concordance with the presumed seizure onset zone in six of eight patients with structural-lesions and five of six non-lesional patients. The most statistically significant haemodynamic cluster was localizable at sub-lobar level within the presumed seizure onset zone in six patients. The degree of concordance of haemodynamic maps was significantly better (P < 0.05) for the ictal-onset phase [entirely concordant/concordant plus (13/20; 65%) + some concordance (4/20; 20%) = 17/20; 85%] than ictal-established [entirely concordant/concordant plus (5/13; 38%) + some concordance (4/13; 31%) = 9/13; 69%] and late ictal [concordant plus (1/9; 11%) + some concordance (4/9; 44%) = 5/9; 55%] phases. Ictal propagation-related haemodynamic changes were also seen in symptomatogenic areas (9/20; 45%) and the default mode network (13/20; 65%). A common pattern of preictal changes was seen in 15 patients, starting between 98 and 14 s before electrographic seizure onset, and the maps had a degree of concordance with the presumed seizure onset zone in 10 patients. In conclusion, preictal and ictal haemodynamic changes in refractory focal seizures can non-invasively localize seizure onset at sub-lobar/gyral level when ictal scalp-electroencephalography is not helpful.

Stretching the limbs? Tonic spasms in multiple sclerosis

A 23-year-old man with a clinically isolated syndrome (right optic neuritis) diagnosed 6 months before, presented with recurrent, brief, painful, stereotyped, involuntary posturing movements of the left upper limb. The neurological examination was otherwise unremarkable (except for right optic atrophy). Intravenous methylprednisolone was initiated; the paroxysms persisted and worsened 7&emsp14;days later, as the left lower limb and hemiface became affected. A video-EEG showed no epileptiform activity despite the movements. Brain MRI revealed new lesions affecting the right pyramidal tract, contralateral to the clinical manifestations. Valproate was prescribed and the paroxysms were completely resolved 5 days later. Tonic spasms are classically, although infrequently, seen in multiple sclerosis, and may clinically resemble primary paroxysmal dyskinesias or even focal motor epileptic seizures.

Resection of the epileptogenic lesion abolishes seizures and reduces inflammatory cytokines of patients with temporal lobe epilepsy

Persistent neuroinflammation is implicated in the pathogenesis of seizures and neuronal degeneration of temporal lobe epilepsy (TLE). Circulating level of inflammatory cytokines was determined during inter-ictal period of 25 non-operated and 10 patients (OP) submitted to anterior temporal lobectomy. OP patients showed marked reduction of IL-1β, TNFα, MIP-1α, but not IL-6 and TGF-β1. Paired analysis done before and after lobectomy showed reduction of inflammatory cytokines but increased TGF-β1 levels, and lack of seizures for more than 6 months. Maintenance of high TGF-β1 and IL-6 cytokines in both groups suggests a role in down-regulation of neuroinflammation and promotion of brain tissue remodeling for neuronal reorganization.

Epilepsy surgery of the temporal lobe in pediatric population: a retrospective analysis

BACKGROUND

There is still some reluctance to refer pediatric patients for epilepsy surgery, despite evidence of success in retrospective series.

OBJECTIVE

To describe surgical experience and long-term outcome in pediatric temporal lobe epilepsy (TLE) at a single institution.

METHODS

Retrospective review of pediatric (<18-years-old) TLE patients who underwent surgery between November 1996 and December 2006 at Cleveland Clinic Epilepsy Center. Cox proportional hazard modeling was used to assess outcome predictors.

RESULTS

One hundred thirty pediatric patients met study criteria. Mean time between seizure onset and surgery was 6.3 years. Invasive evaluation was used in 32 patients (24.5%). Hippocampal sclerosis was present in 70 patients (53.8%), either alone or associated in dual pathology. The complication rate was 7%. The seizure-freedom rates at 1, 2, 5, and 12 years were 76%, 72%, 54%, and 41%, respectively (Kaplan-Meier). With the use of the Engel outcome classification, 98 (75.3%) patients were class I, 11 (8.5%) class II, 9 (7%) class III, and 12 (9.2%) were class IV at last follow-up. Only 4 (3.1%) patients underwent reoperations. Antiepileptic drugs (AEDs) were discontinued in 36 patients (28.3%) in a mean period of 18 months (SD ± 17 months; range, 6-102 months). Although left-sided resection, lower number of preoperative AED trials (≤ 4), and tumor pathology correlated with favorable seizure outcomes, extensive surgical resection remained the only significant outcome predictor after multivariate analysis (P = .007; HR = 0.13 [95% confidence interval 0.007-0.64]).

CONCLUSION

Careful selection of surgical candidates by multidisciplinary evaluations is required. Long-term seizure control is achieved successfully with acceptable low complication rates.

Parasomnias and nocturnal frontal lobe epilepsy (NFLE): lights and shadows--controversial points in the differential diagnosis

Nocturnal frontal lobe epilepsy (NFLE) is characterized by seizures with complex, often bizarre, violent behaviour arising only or mainly during sleep. These unusual seizures and their occurrence during sleep are often accompanied by normal EEG tracings and neuroradiological findings, making it difficult to distinguish NFLE seizures from other non-epileptic nocturnal paroxysmal events, namely parasomnias. NFLE was described for the first time in 1981, but, as its epileptic origin was controversial, the condition was called nocturnal paroxysmal dystonia. Even though many aspects of parasomnias and NFLE have been clarified in the last two decades, the problem of differential diagnosis remains a challenge for clinicians. This paper discusses some controversial points still under debate. The difficulties in distinguishing nocturnal epileptic seizures from parasomnias reflect just one aspect of the intriguing issue of the pathophysiological relationships between all types of paroxysmal motor behaviours during sleep.

Temporal lobe epilepsy semiology

Epilepsy represents a multifaceted group of disorders divided into two broad categories, partial and generalized, based on the seizure onset zone. The identification of the neuroanatomic site of seizure onset depends on delineation of seizure semiology by a careful history together with video-EEG, and a variety of neuroimaging technologies such as MRI, fMRI, FDG-PET, MEG, or invasive intracranial EEG recording. Temporal lobe epilepsy (TLE) is the commonest form of focal epilepsy and represents almost 2/3 of cases of intractable epilepsy managed surgically. A history of febrile seizures (especially complex febrile seizures) is common in TLE and is frequently associated with mesial temporal sclerosis (the commonest form of TLE). Seizure auras occur in many TLE patients and often exhibit features that are relatively specific for TLE but few are of lateralizing value. Automatisms, however, often have lateralizing significance. Careful study of seizure semiology remains invaluable in addressing the search for the seizure onset zone.

No response to acoustic stimuli: absence or akinetic seizure?

Absence seizures are defined by a loss of consciousness during generalized spike-wave discharges (SWCs). We describe a patient who did not respond to acoustic stimuli during generalized SWCs, but who had full recall of any test word given during the SWCs. Our patient's inability to move illustrates that the clinical features during generalized SWCs need to be tested differentially. This pertains especially to studies that evaluate the pathophysiological correlates during SWCs.

Hyperkinetic seizures in patients with temporal lobe epilepsy: clinical features and outcome after temporal lobe resection

PURPOSE

Temporal lobe epilepsy (TLE) is usually associated with automatisms. Hyperkinetic seizures are supposed to be unusual. Because we witnessed several patients with TLE and ictal hyperkinetic symptoms, we retrospectively assessed the number, clinical findings, and seizure outcome in such patients who had undergone temporal lobe resection.

METHODS

We reviewed medical history, video-electroencephalography (EEG) recording and neuroimaging of adult patients who underwent epilepsy surgery for TLE at the Kork Epilepsy Center over the last 20 years with a minimum postoperative follow-up of 12 months.

KEY FINDINGS

Among 294 patients who were resected exclusively in the temporal region, we identified 17 (6%) who presented with hyperkinetic semiology such as violent vocalization, complex movements of the proximal segments of the limbs, rotation of the trunk, pelvic thrusting, or early tonic or dystonic posturing. Most of the patients had a preceding aura. Ictal EEG activity was located in the corresponding temporal region, usually with a wide distribution over temporal electrodes with fast spread to unilateral frontal electrodes and to the contralateral side. Neuroimaging revealed extended lesions in the temporal lobe involving mesial and neocortical structures. Most of the patients underwent classical anterior temporal lobe resection including amygdalo-hippocampectomy. Fourteen patients (82%) became completely seizure-free (Engel class Ia). Histopathology showed mainly focal cortical dysplasia plus hippocampal sclerosis.

SIGNIFICANCE

Hyperkinetic seizure semiology may occasionally occur in patients with TLE and is, therefore, no contradiction to the hypothesis of TLE if scalp EEG patterns and neuroimaging findings correspond. The postoperative seizure outcome is favorable in such patients and not different from outcome data in classical TLE.

Localization of pediatric seizure semiology

OBJECTIVE

The aim of this study was to evaluate the relationship between semiology of seizures in children and adolescents to the corresponding EEG localization.

METHODS

Charts of 225 consecutive pediatric epilepsy patients undergoing Video-EEG monitoring (VEM) over 2 years were reviewed. Seizure semiology recorded during VEM was classified according to ILAE seizure semiology terminology and EEG localization, and analyzed based on onset as defined by the EEG data (generalized, frontal, temporal, parietal, occipital or multilobar).

RESULTS

A total of 1008 seizures were analyzed in 225 children (mean age 8.5 years, range 0-20), with 50% boys. Auras and seizures with automatisms arose predominantly from the temporal lobes (p<0.001). Tonic, clonic and tonic-clonic seizures had most commonly generalized onset (p<0.001). Hypomotor seizures were most frequently seen from the frontal lobes (p<0.001). Hypermotor seizures had most commonly temporal lobe or multiple lobe onset (p<0.001 and p<0.05 respectively). Atonic, myoclonic seizures and epileptic spasms had almost exclusively a generalized onset (p<0.001).

CONCLUSIONS

Different seizure semiologies relate to specific brain regions, with overlap between focal and generalized semiological seizure types, as identified electrographically.

SIGNIFICANCE

Semiology of seizures can provide important information for epilepsy localization, and should not be overlooked, especially in patients undergoing pre-surgical evaluation. Separation of clinical seizure description and EEG findings may be useful, in particular when only incomplete information is available. i.e. during the first office visit.

Quantitative movement analysis differentiates focal seizures characterized by automatisms

The analysis of epileptic seizures is typically performed by visual inspection, limited by interrater variation. Our aim was to differentiate seizures characterized by automatisms with an objective, quantitative movement analysis. In part 1 of this study we found parameters (extent and speed of movement of the wrist and trunk) separating seizures with predominant proximal (hyperkinetic, n=10) and distal (automotor, n=10) limb automatisms (P<0.002). For each movement parameter we used the lowest value recorded for a hyperkinetic seizure in part 1 as the cutoff parameter in part 2 on a consecutive sample of 100 motor seizures. As in part 1, the difference between hyperkinetic and non-hyperkinetic seizures was highly significant (<0.001). When all movement parameters were above the threshold, a hyperkinetic seizure was identified with a probability of 80.8%, but the probability for a non-hyperkinetic seizure to have all parameters above the threshold was only 0.02%.

Clinical significance of ictal high frequency oscillations in medial temporal lobe epilepsy

OBJECTIVE

To clarify the clinical significance of ictal high frequency oscillations (HFO) in the medial temporal lobe.

METHODS

This study included 19 patients who underwent intracranial electrode implantation in bilateral temporal lobes and had at least one seizure recorded at 1kHz sampling rate. The characteristics of ictal HFO in the medial temporal lobe, and the relations between the presence of HFO, pathology, and postoperative seizure outcome were analyzed.

RESULTS

Ictal HFO were detected from medial temporal structures in 11 patients with medial temporal lobe epilepsy (MTLE). Among eight patients without HFO, only three were diagnosed with MTLE. Ictal HFO were detected from unilateral medial temporal structures ipsilateral to the side of hippocampal sclerosis (HS). In one patient with bitemporal independent seizure onset, ictal HFO were detected only on the side of HS. HS was detected in all 11 patients with HFO, but in only one of four patients without HFO. Seizure outcome did not differ between patients with and without HFO.

CONCLUSIONS

Ictal HFO in the medial temporal lobe may be a specific marker for MTLE with HS.

SIGNIFICANCE

Recording of ictal HFO in the medial temporal lobe may be useful for presurgical evaluation of MTLE.

Interictal alterations of cytokines and leukocytes in patients with active epilepsy

BACKGROUND

Involvement of the innate immune system in the pathogenesis of epilepsies has been suggested but possible interactions between the immune system and human epilepsy remain unclear. We analyzed the interictal immuno-phenotype of leukocyte subsets and proinflammatory cytokine profiles in epileptic patients and correlated them with the epilepsy syndrome.

METHODS

101 patients with active focal or generalized epilepsy were prospectively included and compared to 36 healthy controls. Immuno-phenotype of leukocyte subsets and cytokines IL-1β, IL-6 and tnfα were measured in peripheral blood. Multivariate analyses were performed to test group differences.

RESULTS

As compared to controls, the patients showed an elevated percentage of monocytes (18.06±7.08% vs. 12.68±4.55%, p<0.001), NK cells (14.88±7.08% vs. 11.43±5.41%, p=0.019) and IL-6 concentration (3.33±3.11 pg/ml vs. 1.5±1.36 pg/ml, p=0.002). This remained true when focal epilepsies or generalized epilepsies were compared separately to controls but only focal epilepsies showed additionally a decrease in B lymphocyts (8.16±3.76% vs. 11.54±4.2%, p<0.001). Treatment with lamotrigine was associated with a higher percentage of B lymphocytes and valproate with an increased percentage of CD4(+) T lymphocytes. Therapy with levetiracetam showed a trend towards decreased CD8(+) T cell counts. No significant differences were seen between focal and generalized epilepsies and between temporal and extratemporal lobe epilepsies.

CONCLUSION

Patients with active epilepsy revealed interictal alterations of the immune system which varied among specific syndromes and were influenced by antiepileptic drug treatment.

Long term outcome in patients not initially seizure free after resective epilepsy surgery

PURPOSE

To assess the long-term seizure outcome and find predictors of outcome for patients who were not initially seizure free 6 months after epilepsy surgery.

METHODS

We retrospectively reviewed all adult patients who underwent epilepsy surgery at the Epilepsy Center Bethel, between 1992 and 2003. There were 266 patients included in this analysis.

RESULTS

Of the 266 patients who were included in this study, the probability of becoming seizure free was 12% (95%CI 8-16%) after 2 years, 19.5% (95%CI 15-24%) after 5 years and 34.7% (95%CI 28-41%) after 10 years. In patients who had auras only, the probability of being seizure free was 18.2% after 2 years, 25.5% after 5 years, and 39.1% after 10 years. In the multiregression analysis, the EEG carried out 2 years after surgery, a psychic aura, the frequency of postoperative focal seizures and hypermotor seizures predicted seizure remission in the long-term outcome.

CONCLUSIONS

The frequency and type of postoperative seizures are critical determinants for long-term outcome. Seizure semiology may be the clue to a precise diagnosis and long-term prognosis of epilepsy.

Management and long-term outcome in patients presenting with ictal asystole or bradycardia

PURPOSE

Ictal asystole (IA) and ictal bradycardia (IB) are rare autonomic symptoms during epileptic seizures and may be potentially life-threatening. Guidelines for the care of these patients are missing. The aim of this multicenter study was to evaluate the management and long-term outcome in patients with IA and IB.

PATIENTS AND METHODS

All patients with IA and IB were included from four epilepsy centers (Bielefeld, Kork, Marburg, and Zürich) from 2002 until 2009. Using a standardized assessment form, clinical data, treatment decisions, and outcomes were extracted from patient charts and simultaneous electroencephalography/electrocardiography (EEG/ECG) recordings.

KEY FINDINGS

Seizures with IA or IB were identified in 16 patients. In all patients an associated temporal seizure pattern was recorded and in 15 patients, sudden falls, fainting, or trauma was previously reported or recorded during the monitoring. In three patients (18.8%) diagnosis of focal epilepsy was newly established and anticonvulsive treatment was initiated. Two patients with refractory epilepsy underwent epilepsy surgery. In seven patients (43.8%) a cardiac pacemaker was implanted. In 14 of 16 treated patients, seizure freedom (n = 5) or absence of sudden falls, fainting, or trauma (n = 9) could be achieved. Two patients denied epilepsy surgery as well as a pacemaker and continue to have frequent falls and trauma.

SIGNIFICANCE

Our study demonstrates that epilepsy surgery and antiepileptic drugs may lead to sustained freedom of seizures as well as ictal syncope. In drug-resistant patients not suitable for epilepsy surgery, implantation of a cardiac pacemaker may prevent sudden falls as well as trauma. Based on our results and previously reported cases we propose a treatment algorithm.

Apical temporal lobe resection; "tailored" hippocampus-sparing resection based on presurgical evaluation data

BACKGROUND

It is the aim of epilepsy surgery in patients with lesional epilepsy for the surgeon to not only remove the lesion itself, but also the epileptogenic zone. Here, we report our experience with a modified temporal resection technique confined to the apical temporal lobe, i.e., sparing the hippocampal formation in patients with epileptogenic lesions in the anterior part of the temporal lobe. This apical temporal lobe resection (aTLR) includes tailored lesionectomy, amygdalectomy, and resection of the mesial structures only in the apex of the temporal lobe. This paper presents our surgical technical details and the outcome of aTLR.

METHODS

Between 2001 and 2008, aTLR was performed in 61 patients. All patients underwent comprehensive presurgical evaluation including video-EEG monitoring, magnetic resonance imaging (MRI), and neuropsychological testing. All patients had a lesion in the apex of the temporal lobe and a normal hippocampus as seen in MRI, as well as intact memory functions in neuropsychological examination. There were 33 males (54.1%) and 28 females (45.9%). The mean age in years at epilepsy onset was 20.2 ± 13.4, the mean age at epilepsy surgery was 32.1 ± 11.9, the mean preoperative epilepsy duration was 11.8 ± 8.8 years and the mean duration of follow-up was 2.1 ± 1.3 years (range 0.5-6 years).

RESULTS

Fifty-four (88.5%) of 61 patients were in Engel Class 1 at 6 months, 38 (80.9%) of 47 at 2 years and nine (81.8%) of 11 at the 5 year follow-up. Histopathological examination showed tumors in 31 patients, FCD in ten patients, amygdala sclerosis in seven patients, cavernomas in six patients, unspecific reactions in eight patients, and gliosis in one patient. Surgical complications occurred in four patients: one had a permanent and three had transient complications which could be successfully treated. Fifty (82%) resections were considered to be complete resections as evaluated by serial postoperative MRI, seven patients (11.5%) had incomplete resection of the preoperative MRI lesion and in four patients (6.6%) it remained unclear. Fifteen patients (29.4%) were withdrawn from antiepileptic drugs for more than 2 years without relapse. Postoperative neuropsychological examination revealed worsening of memory performance in two patients (3.2%) and improved or no changes in the rest of the patients.

CONCLUSIONS

Apical temporal resection sparing the mesial temporal structures is an effective procedure with good long-term seizure outcome in patients with refractory epilepsy due to lesions confined to the apex of the temporal lobe.

Seizure semiology and aging

The incidence of epilepsy is high in older individuals. However, epilepsy in the elderly may be underdiagnosed and undertreated because of diagnostic difficulties. The main goal of this study was to determine whether seizure semiology differs between older and younger adults with epilepsy in the outpatient setting. Fifty patients with focal epilepsy aged 55 years and older and 50 patients aged between 18 and 45 years were included. Review of medical records contained detailed seizure description. There were no differences in seizure semiology between groups, except that subtle perceptions of transient confusion were seen in older patients but not in younger patients (P=0.0028). Older patients had less generalized motor seizures, but the differences between groups did not reach significance (P=0.01). Older patients may present with subtle symptoms of seizures characterized by brief periods of confusion, which may contribute to greater difficulty diagnosing seizures in the elderly.

Localizing and lateralizing features of auras and seizures

The symptomatology of auras and seizures is a reflection of activation of specific parts of the brain by the ictal discharge, the location and extent of which represent the symptomatogenic zone. The symptomatogenic zone is presumably, though not necessarily, in close proximity to the epileptogenic zone, the area responsible for seizure generation, the complete removal or disconnection of which is necessary for seizure freedom. Knowledge about the symptomatogenic zone in focal epilepsy is acquired through careful video/EEG monitoring and behavioral correlation of seizures and electrical stimulation studies. Ictal symptomatogy provides important lateralizing and/or localizing information in the presurgical assessment of epilepsy surgery candidates. As the initial symptoms of epileptic seizures, many types of auras have highly significant localizing or lateralizing value. Similarly, motor signs during focal and secondary generalized seizures, language manifestations, and autonomic features offer reliable clues to the delineation of the epileptogenic zone. Some focal epilepsies (e.g., neocortical temporal lobe epilepsy, insular lobe epilepsy, temporal-plus epilepsies, and parieto-occipital lobe epilepsy) generate seizure manifestations that mimic temporal lobe epilepsy, potentially contributing to surgical failure. To optimize surgical outcome, careful interpretation of ictal symptomatology in conjunction with other components of the presurgical evaluation is required.

Guidelines for epilepsy management in India classification of seizures and epilepsy syndromes

This article is part of the Guidelines for Epilepsy management in India. This article reviews the classification systems used for epileptic seizures and epilepsy and present the recommendations based on current evidence. At present, epilepsy is classified according to seizure type and epilepsy syndrome using the universally accepted International League Against Epilepsy (ILAE) classification of epileptic seizures and epilepsy syndromes. A multi-axial classification system incorporating ictal phenomenology, seizure type, epilepsy syndrome, etiology and impairments is being developed by the ILAE task force. The need to consider age-related epilepsy syndromes is particularly important in children with epilepsy. The correct classification of seizure type and epilepsy syndrome helps the individual with epilepsy to receive appropriate investigations, treatment, and information about the likely prognosis.

Ictal patterns in children: an illustrated review

Detailed knowledge of electroencephalographic patterns accompanying epileptic seizures in children is paramount to the correct identification of epileptic seizures and syndromes. In this article, we present a review of ictal patterns of different seizure types in children, illustrating with examples collected in our video-EEG laboratory at Pequeno Príncipe Hospital.

Temporal lobe epilepsy surgery failures: predictors of seizure recurrence, yield of reevaluation, and outcome following reoperation

Object

The authors provide a systematic analysis of electroclinical characteristics in patients with persistent seizures following temporal lobe epilepsy (TLE) surgery and identify ideal candidates for reoperation.

Methods

The authors retrospectively reviewed the records of 68 adult patients (mean follow-up 8.7 years) who underwent a video electroencephalography evaluation and high-resolution imaging after failed TLE surgery performed between 1990 and 2004 at The Cleveland Clinic. Multivariate logistic regression analyses were performed to identify predictors of the yield of a repeat evaluation, location of the recurrence focus, and outcome following reoperation.

Results

Although a focus of recurrence was identified in 44 patients, only 15 underwent reoperation, and only 6 of these became seizure free. Localized foci of recurrence were successfully identified in patients with early (within 1 postoperative year) and frequent (≥ 4 per month) recurrent seizures (yield of 100% if both conditions were fulfilled). Predictors of contiguity of the focus of recurrence to the initial surgical bed were variable depending on the type of the initial surgery: patients with baseline contralateral temporal spiking were 6 times (OR 6.34, p < 0.05) more likely to experience seizure recurrence from the contralateral temporal lobe after a “standard” temporal lobectomy, while the need to use subdural electrodes and the timing of recurrence were more significant following limited temporal resections. The focus of recurrence was distant to the original surgical bed when subdural electrodes were used prior to first surgery (OR 28.0, p = 0.01) or when seizures recurred early (within < 6 postoperative months; OR 12.5, p = 0.04). With reoperation, only patients with mesial and basal extension of the temporal resections became seizure free. Interestingly, seizure freedom was achieved with medical therapy alone in 42% of patients with a nonidentifiable recurrence focus as opposed to 4% of those with an unoperated identifiable focus.

Conclusions

The timing and frequency of recurrent seizures following unsuccessful TLE surgery provide useful guidelines for the yield of a surgical reevaluation, and potentially for the mechanisms of surgical failure.

Classification of epileptic motor manifestations using inertial and magnetic sensors

In order to characterize objectively the succession of movements observed during motor seizures, inertial and magnetic sensors were placed on epileptic patients. Video recordings synchronized with motion recordings were analyzed visually during seizures and divided, for each limb, into events corresponding to different classes of motor manifestations. For each classified event, features were extracted and a subset selection was automated using artificial neural networks. The best artificial neural network was simulated on whole recordings to generate a stereotypic evolution of motor manifestations that we called motorograms. It is shown that motorograms can point out seizure movements and emphasize epileptic patterns.