Clinical seizure lateralization in frontal lobe epilepsy

Approach to Patients with Seizures and Epilepsy: A Guide for Primary Care Physicians

Seizures and epilepsy are common neurologic conditions that are frequently encountered in the outpatient primary care setting. An accurate diagnosis relies on a thorough clinical history and evaluation. Understanding seizure semiology and classification is crucial in conducting the initial assessment. Knowledge of common seizure triggers and provoking factors can further guide diagnostic testing and initial management. The pharmacodynamic characteristics and side effect profiles of anti-seizure medications are important considerations when deciding treatment and counseling patients, particularly those with comorbidities and in special populations such as patient of childbearing potential.

Lateralizing value and clinicoradiological features of asymmetric last clonic jerks in temporal and extratemporal epilepsy

Seizure semiology and electroencephalograph (EEG) are very important for determining seizure type, hemisphere lateralization, or localization. Clinical symptoms of focal seizures, as well as findings at the onset or end of a focal to bilateral tonic-clonic seizure (FBTCS), are highly informative for lateralization. This study aimed to investigate the relationship of asymmetric last clonic jerk in patients with temporal or extratemporal lobe epilepsy with pathologies, localization, lateralization, or other semiological findings detected in neuroimaging or neuro psychometric tests and its positive predictive value for the detection of hemisphere lateralization based on seizure onset ictal EEG activation. 44 patients with asymmetric last clonic jerks (aLCJ) who were followed up in our VEM unit were randomized 1:1 with epilepsy patients without. In patients with ipsilateral automatism and contralateral posture or gustatory and olfactory hallucinations aLCJ was less or absent. In patients with unilateral tonic activity, aLCJ was more common. The positive predictive value of aLCJ for ictal EEG activation lateralization was 86.36%. In conclusion, asymmetric last clonic beat is valuable for lateralization of FBTCS and should be considered. Its presence strongly and reliably lateralizes to the side of seizure onset.

Ictal Coprolalia: Three Cases with Nondominat Frontal Lobe Involvement and Review of the Literature

Objective: Coprolalia is defined as the involuntary use of obscene, socially unacceptable, and derogatory words. Ictal coprolalia is a rare presentation of epilepsy. This study aimed to determine the localizing and lateralizing value and frequency of ictal coprolalia in epilepsy patients. Methods: Medical files, discharge summaries, and electroencephalography (EEG) reports of 2238 patients were reviewed retrospectively. We identified patients who suffered from ictal coprolalia. Electroencephalography reports, neuroimaging [brain magnetic resonance imaging (MRI), fluorodeoxyglucose positron emission tomography (FDG-PET), single-photon emission computerized tomography (SPECT)] records, F-18 FDG fused on MRI images, and ictal SPECT fused on MRI images were evaluated. Also, original and review articles were identified through a systematic search of Pubmed, Scopus, and Clarivate Analytics. Results: Ictal coprolalia was detected in 3 male (0.15%) patients. In all patients, ictal semiology was extratemporal-frontal type, and potential/proven epileptic focus was non-dominant hemisphere frontal lobe. Topectomy was done in one of the patients, including the suspected dysplastic area plus the area where the electroencephalographic ictal and interictal changes occur, on the left frontal lobe, and the patient had an Engel's classification class IIA. The data depending on the published cases showed that ictal coprolalia was dominant in the male gender and the responsible epileptic area tended to be located in the non-dominant hemisphere frontotemporal region. Conclusion: The rate of ictal coprolalia in the Turkish population is lower compared to other series. Our results are consistent with previous studies in which reported that male preponderance for ictal coprolalia and involvement of non-dominant frontal lobe.

Ictal Blinking: Reappraisal of the Lateralization and Localization Value in Focal Seizures

Introduction. Although ictal blinking is significantly more frequent in generalized epilepsy, it has been reported as a rare but useful lateralizing sign in focal seizures when it is not associated with facial clonic twitching. This study aimed to raise awareness of eye blinking as a semiological lateralizing sign. Method. Our database over an 11-year period reviewed retrospectively to assess patients who had ictal blinking associated with focal seizures. Results. Among 632 patients, 14 (2.2%), who had 3 to 13 (7 ± 3) seizures during video-EEG monitoring, were included. Twenty-five percent of all 92 seizures displayed ictal blinking and each patient had one to five seizures with ictal blinking. Ictal blinking was unilateral in 17%, asymmetrical in 22% and symmetrical in 61%. The blinking appeared with a mean latency of 6.3 s (range 0-39) after the clinical seizure-onset, localized most often to fronto-temporal, then in frontal or occipital regions. Blinking was ipsilateral to ictal scalp EEG lateralization side in 83% (5/6) of the patients with unilateral/asymmetrical blinking. The exact lateralization and localization of ictal activity could not have been determined via EEG in most of the patients with symmetrical blinking, remarkably. Conclusions. Unilateral/asymmetrical blinking is one of the early components of the seizures and appears as a useful lateralizing sign, often associated with fronto-temporal seizure-onset. Symmetrical blinking, on the other hand, did not seem to be valuable in lateralization and localization of focal seizures. Future studies using invasive recordings and periocular electrodes are needed to evaluate the value of blinking in lateralization and localization.

Does seizure propagate within or across intrinsic brain networks? An intracranial EEG study

BACKGROUND

Understanding the spatiotemporal propagation profiles of seizures is crucial for the preoperative assessment of epilepsy patients. The present study aimed to investigate whether seizures exhibit propagation patterns that align with intrinsic networks (INs).

METHODS

A quantitative analysis was conducted to examine ictal fast activity (IFA). The Epileptogenicity Index (EI) was employed to assess the epileptogenicity, spectral features, and temporal characteristics of IFA. Intra-network and inter-network comparisons were made regarding the IFA-related metrics. Additionally, the metrics were correlated with Euclidean distance. Network connection maps were generated to visualize seizures originating from different INs, allowing for comparisons between distinct groups.

RESULTS

Data for 81 seizures in 43 subjects were captured using stereoelectroencephalography implantation. Three metrics were compared: EI, time involvement (TI), and energy ratio index (ERI). Intra-network channels exhibited higher EI, earlier involvement of IFA, and stronger high-frequency energy. These findings were further validated through subgroup analyses stratified by neuropathology, seizure type, and seizure origination lobe. Correlation analyses revealed a negative association between distance and both EI and ERI, while distance exhibited a positive correlation with TI. Seizures originating from different INs exhibited varying propagation characteristics.

CONCLUSIONS

The study findings highlight the dominant role of intra-network dynamics over inter-network during seizure propagation. These results contribute to our understanding of seizure dynamics and their relationship with INs.

Deep phenotyping of frontal lobe epilepsy compared to other epilepsy syndromes

AIMS

Frontal lobe epilepsy (FLE) is understudied and often misdiagnosed. We sought to comprehensively phenotype FLE and to differentiate FLE from other focal and generalised epilepsy syndromes.

METHODS

This was a retrospective, observational cohort study of 1078 cases of confirmed epilepsy in a tertiary neurology centre in London. Data sources were electronic health records, investigation reports and clinical letters.

RESULTS

166 patients had FLE based on clinical findings and investigations-97 with identifiable electroencephalography (EEG) foci in frontal areas (definite FLE), while 69 had no frontal EEG foci (probable FLE). Apart from EEG findings, probable and definite FLE did not differ in other features. FLE was distinct from generalized epilepsy, which tended to present with tonic-clonic seizures and be due to genetic causes. FLE and temporal lobe epilepsy (TLE) both featured focal unaware seizures and underlying structural or metabolic aetiology. FLE, TLE and generalized epilepsy differed in their EEG (P = 0.0003) and MRI (P = 0.002) findings, where FLE had a higher rate of normal EEG and abnormal MRI findings compared to TLE.

CONCLUSIONS

EEG is often normal for FLE, and abnormalities are commonly identified with MRI. There was no difference in the clinical features of definite and probable FLE, suggesting they represent the same clinical entity. The diagnosis of FLE can be made even when scalp EEG is normal. This large medical cohort provides hallmark features of FLE that differentiate it from TLE and other epilepsy syndromes.

Motor seizure semiology

Motor semiology is a major component of epilepsy evaluation, which provides essential information on seizure classification and helps in seizure localization. The typical motor seizures include tonic, clonic, tonic-clonic, myoclonic, atonic, epileptic spasms, automatisms, and hyperkinetic seizures. Compared to the "positive" motor signs, negative motor phenomena, for example, atonic seizures and Todd's paralysis are also crucial in seizure analysis. Several motor signs, for example, version, unilateral dystonia, figure 4 sign, M2e sign, and asymmetric clonic ending, are commonly observed and have significant clinical value in seizure localization. The purpose of this chapter is to review the localization value and pathophysiology associated with the well-defined motor seizure semiology using updated knowledge from intracranial electroencephalographic recordings, particularly stereoelectroencephalography.

Patterns of hypometabolism in frontal lobe epilepsy originating in different frontal regions

Objectives

Analysis of FDG‐PET imaging commonly shows that hypometabolism extends into extra‐epileptogenic zones (extra‐EZ). This study investigates the distribution patterns of hypometabolism in frontal lobe epilepsy (FLE) originating in different frontal regions.

Methods

Sixty‐four patients with FLE were grouped by EZ localization according to Brodmann areas (BAs): Group 1 (the frontal motor and premotor area), BAs 4, 6, and 8; Group 2 (the inferior frontal gyrus and opercular area), BAs 44, 45, and 47; Group 3 (the dorsal prefrontal area), BAs 9, 10, 11, and 46; and Group 4 (the medial frontal and anterior cingulate gyrus), BAs 32 and 24. Regions of extra‐EZ hypometabolism were statistically analyzed between FLE groups and healthy controls. Correlation analysis was performed to identify relationships between the intensity of hypometabolism and clinical characteristics.

Results

Significant hypometabolism in the ipsilateral (Groups 1 and 4) or bilateral (Groups 2 and 3) anterior insulae was found. Groups 1 and 4 presented with limited distribution of extra‐EZ hypometabolism, whereas Groups 2 and 3 showed widely distributed extra‐EZ hypometabolism in the rectus gyrus, cingulate gyrus, and other regions. Additionally, the intensity of hypometabolism was correlated with epilepsy duration in Groups 2 and 3.

Conclusions

All FLE groups showed hypometabolism in the anterior insula. In addition, distinct patterns of extra‐EZ hypometabolism were identified for each FLE group. This quantitative FDG‐PET analysis expanded our understanding of the topography of epileptic networks and can guide EZ localization in the future.

Seizure semiology: ILAE glossary of terms and their significance

This educational topical review and Task Force report aims to address learning objectives of the International League Against Epilepsy (ILAE) curriculum. We sought to extract detailed features involving semiology from video recordings and interpret semiological signs and symptoms that reflect the likely localization for focal seizures in patients with epilepsy. This glossary was developed by a working group of the ILAE Commission on Diagnostic Methods incorporating the EEG Task Force. This paper identifies commonly used terms to describe seizure semiology, provides definitions, signs and symptoms, and summarizes their clinical value in localizing and lateralizing focal seizures based on consensus in the published literature. Video-EEG examples are included to illustrate important features of semiology in patients with epilepsy.

Seizure semiology, localization, and the 2017 ILAE seizure classification

In the study of epilepsy, the term semiology is used to comprise the clinical characteristics of a seizure, both subjective symptoms and objective phenomena. It is produced by activation of the symptomagenic zone, and an accurate and comprehensive understanding of the localizing value of seizure semiology is crucial for presurgical evaluation and planning. Myriad publications in epilepsy journals detail correlations between various semiological features and activation of specific cortical regions. Traditionally these studies involved scalp EEG recorded in epilepsy monitoring units. The increasing use of invasive monitoring, and specifically the use of depth electrodes and stereo-electroencephalography, has advanced our understanding of the characteristics of seizures arising from ictal foci deep to the scalp, including the cingulate, insula and operculum. However, the distinction between seizure onset and symptomogenic zones is not always clear. In 2017 the International League Against Epilepsy (ILAE) published an operational classification of seizure types based heavily on seizure semiology. The current paper provides an updated review of the current body of knowledge relating to seizure semiology, incorporating both scalp EEG studies and more recent stereo-electroencephalography discoveries in the framework of the 2017 ILAE classification.

Seizure focus in the frontal interhemispheric fissure leads to ipsilateral isolated eye deviation

OBJECTIVE

Few studies have examined the localization of seizures presenting with ictal eye deviation (ED) in the absence of other motor symptoms. We aimed to investigate differences in the localization of the ictal onset zone (IOZ) between patients with isolated ED and those with ED plus head turning (HT) during focal seizures.

METHODS

We reviewed intracranial video-EEG data for 931 seizures in 80 patients with focal onset epilepsy in whom the IOZ could be confirmed. The 233 seizures in 49 patients with ED were classified into two semiological groups based on initial ED and the presence/absence of HT: (1) isolated ED (i.e., ED without HT), and (2) ED + HT (i.e., ED with HT). We analyzed the localization and lateralization of IOZs in each semiological group. We performed multivariate logistic regression analysis using a mixed-effects to determine the associations between IOZs and isolated ED/ED + HT.

RESULTS

A total of 183 IOZs in 24 patients were included in the isolated ED group, while a total of 143 IOZs in 31 patients were included in the ED + HT group. Sixty-eight IOZs of eight patients in the isolated ED group were located in the ipsilateral frontal interhemispheric fissure (F-IHF). Only ipsilateral F-IHF was significantly associated with isolated ED (odds ratio [OR], 2.43; 95% confidence interval [CI], 0.37-4.49; P = 0.021). The contralateral lateral frontal cortex (latF) (P = 0.007) and ipsilateral mesial temporal region (mT) (P = 0.029) were significantly associated with ED + HT.

CONCLUSION

The present study is the first to demonstrate that seizures with an F-IHF focus tend to present with initial ipsilateral isolated ED. This finding may aid in identifying the seizure focus in patients with isolated ED prior to resection.

Can semiology differentiate between bilateral tonic-clonic seizures of focal-onset and generalized-onset? A systematic review

OBJECTIVE

Bilateral tonic-clonic seizures are encountered in both focal and generalized epilepsies. We reviewed the literature regarding the presence of focal signs in generalized-onset tonic-clonic seizures (GOTCS) and the utility of semiology in differentiating those from focal to bilateral tonic-clonic seizures (FBTCS).

METHODS

We conducted a comprehensive literature search using four electronic databases (Medline, Embase, Web of Science, and Psychinfo) and constructed a systematic review in keeping with the Preferred Items for Systematic Reviews and Meta-analyses guidelines.

RESULTS

We included 13 studies on focal semiological features of GOTCS. These studies included a total of 952 participants. The key focal signs described in GOTCS included: early head version, figure of four sign, asymmetric seizure termination, and a multitude of auras as well as automatisms. Additionally, we reviewed five studies that investigated the use of semiology to differentiate GOTCS from FBTCS; these studies had a total of 289 participants. Asymmetry in clonic phase, side-to-side axial movements, asymmetrical seizure termination, figure of four sign, index finger pointing, and fanning posture of the hand were found to be significantly more frequent in FBTCS compared with GOTCS. Furthermore, combinations of focal semiological features occurring in a single seizure were found to be suggestive of FBTCS rather than GOTCS.

CONCLUSION

Focal signs are often evident in GOTCS. Though the observation of multiple focal signs within a given seizure may be in favor of an FBTCS, our findings caution against differentiating between the two seizure types based on semiology alone due to considerable overlap in focal features.

Voxel-based morphometric MRI post-processing and PET/MRI co-registration reveal subtle abnormalities in cingulate epilepsy

OBJECTIVE

Diagnostic challenges exist in the presurgical evaluation of patients with magnetic resonance imaging (MRI) negative cingulate epilepsy (CE) because of the heterogeneity in clinical semiology and lack of localizing findings on scalp electroencephalographic (EEG) recordings. We aimed to examine the neuroimaging characteristics in a consecutive cohort of patients with MRI-negative CE with a focus on two image post-processing methods, including the MRI post-processing morphometric analysis program (MAP) and ¹⁸F-fluorodeoxyglucose-positron emission tomography-MRI (PET/MRI) co-registration.

METHODS

Included in this retrospective study were patients with MRI-negative CE who met the following criteria: negative on preoperative MRI, invasive EEG (iEEG) confirmed cingulate gyrus-onset seizures, surgical resection of the cingulate gyrus with/without adjacent cortex, and seizure-free for more than 12 months. MAP and PET/MRI co-registration were performed and investigated by comparison to ictal intracranial EEG findings. Other characteristics obtained from scalp EEG, magnetoencephalography (MEG), iEEG, and pathological study were also reported.

RESULTS

Ten patients were included, of which eight were diagnosed with anterior CE, one with middle CE, and one with posterior CE. The semiology included fear, embarrassment, vocalization, ictal pouting, asymmetric tonic posture, hypermotor, and automatism. Scalp EEG revealed unilateral or bilateral frontal-temporal onset. MEG localized the dipoles correctly in one patient (1/10). MAP detected subtle abnormalities in regions concordant with iEEG onset in seven patients (7/10) while PET/MRI co-registration revealed focal concordant hypometabolism in five patients (5/10). Combining MAP with PET/MRI co-registration improved the detection rate to 90 % in this cohort. The pathology was focal cortical dysplasia (FCD), including FCD type IIA in three, type IIB in three, and type I in four.

CONCLUSION

MAP and PET/MRI co-registration show promising results in identifying subtle FCD abnormalities in CE with negative results on conventional MRI, which can be otherwise challenging. More importantly, a combination of MRI post-processing and PET/MRI co-registration can greatly improve the identification of epileptic abnormalities, which can be used as surgical target. MAP and PET/MRI co-registration should be incorporated into the routine presurgical evaluation.

Different faces of frontal lobe epilepsy: The clinical, electrophysiologic, and imaging experience of a tertiary center

OBJECTIVE

Frontal lobe epilepsy (FLE) is the second most common epilepsy among drug-resistant focal epilepsies. Semiologic and electrophysiologic features of FLE present some difficulties because frontal lobe seizures are brief, accompanied by complex motor activities and emotional signs. The rich connectivity of the frontal lobe with other areas leads to the rapid and widespread propagation of seizure activity, which contribute to the difficulty of evaluating the semiologic and EEG patterns of the seizure. In this study, we investigated semiologic, interictal, ictal, and postictal EEG characteristics; the imaging data of patients with FLE and the possible contribution of these data to localization and lateralization of seizures.

MATERIALS AND METHODS

The medical records of patients who were diagnosed as having FLE between 2010 and 2019 in our clinic were evaluated retrospectively. The diagnosis of FLE was considered either when patients had a structural lesion in the frontal region or seizure semiology and EEG characteristics were compatible with FLE. Clinical, electrophysiologic, and imaging features were investigated in these patients.

RESULTS

We have evaluated 146 seizures in 36 patients (17 lesional and 19 non-lesional according to MRI). There were 110 focal motor or nonmotor seizures, 18 bilateral tonic-clonic seizures, and 18 subclinical seizures. There were 16 patients with aura. The most common semiologic feature was hyperkinetic movements. Among the interictal EEGs, 30.5 % included focal anomalies. Among the ictal EEGs, 69.1 % were non-localizing or lateralizing. The most common ictal pattern was rhythmic theta activity (21.2 %). In four patients, who had non-localizing or lateralizing EEG, the postictal EEG was informative. Our study showed a low percentage of localized FDG-PET, which, however, involved visual analysis.

CONCLUSION

Our results support the previously known difficulties in the determination of the epileptogenic zone of FLE. Semiologic and electrophysiologic correlation studies, longer postictal records, and quantitative analysis of FDG-PET may contribute to a better characterization of the disease.

Calibration of the Epilepsy Questionnaire for Use in a Low-Resource Setting

Background. Burden of epilepsy in sub-Saharan Africa is huge in the midst of shortage of human resource in its health sector. Using skilled staff to supervise and support lower level healthcare workers providing frontline primary healthcare is a pragmatic coping solution. But, lower level health providers face enormous challenges due to absent clinical algorithms or pragmatic rapid diagnostic tests. Objective. This study aimed to determine if the use of an epilepsy questionnaire in a traditional clinical setting would improve semiological details obtained and diagnostic accuracy. Methods. A prospective study was conducted involving patients diagnosed with epilepsy each with an eye witness who had regularly witnessed the seizures. Routine seizure history from clinical documentation and an interviewer-based questionnaire were compared. The data obtained were assessed for content, accuracy, intermethod and test-retest reliability. Results. Sixty-seven patients with a median age of 24 years were recruited. Routine seizure history had obtained less semiological details with inadequate description of nonmotor manifestations and lateralizing motor details. The questionnaire-obtained history showed higher accuracy for generalized onset seizure (0.83 vs. 0.56) and focal onset seizures (0.79 vs. 0.59). The questionnaire-obtained history also had good test-retest reliability for various semiological domains except automatisms. Conclusions. Routine seizure histories are not standardized. The use of a questionnaire goes a long way in improving semiology description in a low-resource setting and guides the health provider on what details to focus on. The use of epilepsy questionnaires should, therefore, be considered to improve semiology, especially in nonspecialist settings.

Ipsiversive ictal eye deviation in inferioposterior temporal lobe epilepsy-Two SEEG cases report

Background

Versive seizure characterized by conjugate eye movement during epileptic seizure has been considered commonly as one of the most valuable semiological signs for epilepsy localization, especially for frontal lobe epilepsy. However, thelateralizing and localizing significance of ictaleye deviation has been questioned by clinical observation of a series of focal epilepsy studies, including frontal, central, temporal, parietal and occipital epilepsy.

Case presentation

Two epileptic cases characterized by ipsiversive eye deviation as initial clinical sign during the habitual epileptic seizures are presented in this paper. The localization of the epileptogenic zone of both of the cases has been confirmed as inferioposterior temporal region by the findings of ictalstereoelectroencephalography (SEEG) and a good result after epileptic surgery. Detailed analysis of the exact position of the key contacts of the SEEG electrodes identified the overlap between the location of the epileptogenic zone and human MT/MST complex, which play a crucial role in the control of smooth pursuit eye movement.

Conclusion

Ipsiversive eye deviation could be the initial clinical sign of inferioposterior temporal lobe epilepsy and attribute to the involvement of human MT/MST complex, especially human MST whichwas located on the anterior/dorsal bank of the anterior occipital sulcus (AOS).

Semiology of hypermotor (hyperkinetic) seizures

BACKGROUND

Hypermotor seizures (HMSs) consist of complex movements involving proximal segments of the limbs and trunk that appear violent and inappropriate for the situation.

METHODS

We analyzed hypermotor seizure videos in seizure-free patients (Engel class I) following resective epilepsy surgery. After completion of video analysis, we reviewed EEG and neuroimaging data.

RESULTS

Search of our epilepsy surgery database yielded 116 patients classified as having hypermotor seizures between 1996 and 2013. From this subset, 17/31 (55%) patients had been seizure-free for >6months (mean follow-up: 3.3years). Mean seizure duration was 35s (range: 6-91s), of which the HM phase lasted a mean of 22s (range: 3-53s). In 16 patients (95%), hypermotor activity was seen at or within 10s of clinical seizure onset. Type I semiology occurred in 6 patients, type II semiology in 10 patients, and 1 patient exhibited features of both. Type I and type II semiologies were noted in patients who had frontal lobe as well as extrafrontal resections. Nonversive head and body turning occurred in 10 patients (ranging from 90° to 270°) which was ipsilateral to the side of resection in all patients and seen both in frontal and extrafrontal resections. Six out of eleven patients with abnormal MRI and 4/6 patients with nonlesional MRI underwent invasive EEG evaluation. Eight patients (47%) had frontal lobe resection, 4/17 (23%) patients had temporal lobe resection, and one patient each had parietal lobe, insular, temporoparietooccipital, or motor sparing resection; 1 patient had functional hemispherectomy.

CONCLUSION

Hypermotor semiology typically occurs at or within 10s after seizure onset. Ipsilateral head/body turning appears to be of lateralizing value whereas asymmetry of limb movement was not lateralizing. Hypermotor semiology is most often seen in frontal lobe epilepsy but may occur in seizures arising from other locations.

Ictal Forced Repetitive Swearing in Frontal Lobe Epilepsy: Case report and review of the literature

Introduction.Dominant presentation of ictal forced repetitive swearing has been rarely addressed and could be misdiagnosed.

Case report.We report a 45-year-old man with a long history of right frontal lobe epilepsy (FLE) who developed forced repetitive swearing during hypermotor seizures. His seizures were refractory to different antiepileptic drugs (AEDs). Scalp video-EEG telemetry suggested a right frontal epileptic focus. Magnetic resonance imaging (MRI) suggested focal cortical dysplasia (FCD) in the right mesial frontal lobe. Intracranial implantation with video-EEG recordings confirmed seizures originating from the MRI lesion. Patient underwent right frontal lobe resection followed by seizure freedom in the last five years on a single AED. Neuropathology confirmed FCD type IIB.

Discussion.The following aspects of the case are discussed: FLE and ictal vocalization, swearing, FLE and aggression. We emphasize the differences among ictal vocalisation, verbal automatism and ictal speech. We propose that ictal swearing might fit a verbal automatism definition.

Conclusion.Ictal forced repetitive swearing can be a manifestation of hypermotor seizures in FLE and should not be misdiagnosed.

Looking for complexity in quantitative semiology of frontal and temporal lobe seizures using neuroethology and graph theory

Epileptic syndromes and seizures are the expression of complex brain systems. Because no analysis of complexity has been applied to epileptic seizure semiology, our goal was to apply neuroethology and graph analysis to the study of the complexity of behavioral manifestations of epileptic seizures in human frontal lobe epilepsy (FLE) and temporal lobe epilepsy (TLE). We analyzed the video recordings of 120 seizures of 18 patients with FLE and 28 seizures of 28 patients with TLE. All patients were seizure-free >1 year after surgery (Engel Class I). All patients' behavioral sequences were analyzed by means of a glossary containing all behaviors and analyzed for neuroethology (Ethomatic software). The same series were used for graph analysis (CYTOSCAPE). Behaviors, displayed as nodes, were connected by edges to other nodes according to their temporal sequence of appearance. Using neuroethology analysis, we confirmed data in the literature such as in FLE: brief/frequent seizures, complex motor behaviors, head and eye version, unilateral/bilateral tonic posturing, speech arrest, vocalization, and rapid postictal recovery and in the case of TLE: presence of epigastric aura, lateralized dystonias, impairment of consciousness/speech during ictal and postictal periods, and development of secondary generalization. Using graph analysis metrics of FLE and TLE confirmed data from flowcharts. However, because of the algorithms we used, they highlighted more powerfully the connectivity and complex associations among behaviors in a quite selective manner, depending on the origin of the seizures. The algorithms we used are commonly employed to track brain connectivity from EEG and MRI sources, which makes our study very promising for future studies of complexity in this field.

Neural network underlying ictal pouting ("chapeau de gendarme") in frontal lobe epilepsy

In order to determine the anatomical neural network underlying ictal pouting (IP), with the mouth turned down like a "chapeau de gendarme", in frontal lobe epilepsy (FLE), we reviewed the video-EEG recordings of 36 patients with FLE who became seizure-free after surgery. We selected the cases presenting IP, defined as a symmetrical and sustained (>5s) lowering of labial commissures with contraction of chin, mimicking an expression of fear, disgust, or menace. Ictal pouting was identified in 11 patients (8 males; 16-48 years old). We analyzed the clinical semiology, imaging, and electrophysiological data associated with IP, including FDG-PET in 10 and SEEG in 9 cases. In 37 analyzed seizures (2-7/patient), IP was an early symptom, occurring during the first 10s in 9 cases. The main associated features consisted of fear, anguish, vegetative disturbances, behavioral disorders (sudden agitation, insults, and fighting), tonic posturing, and complex motor activities. The epileptogenic zone assessed by SEEG involved the mesial frontal areas, especially the anterior cingulate cortex (ACC) in 8 patients, whereas lateral frontal onset with an early spread to the ACC was seen in the other patient. Ictal pouting associated with emotional changes and hypermotor behavior had high localizing value for rostroventral "affective" ACC, whereas less intense facial expressions were related to the dorsal "cognitive" ACC. Fluorodeoxyglucose positron emission tomography demonstrated the involvement of both the ACC and lateral cortex including the anterior insula in all cases. We propose that IP is sustained by reciprocal mesial and lateral frontal interactions involved in emotional and cognitive processes, in which the ACC plays a pivotal role.

Finger snapping during seizures

We describe two patients who showed snapping of the right hand fingers during invasive intracranial EEG evaluation for epilepsy surgery. We correlated the EEG changes with the finger-snapping movements in both patients to determine the underlying pathophysiology of this phenomenon. At the time of finger snapping, EEG spread from the supplementary motor area towards the temporal region was seen, suggesting involvement of these sites.

Ictal unilateral eye blinking and contralateral blink inhibition - A video-EEG study and review of the literature

Introduction

There is limited information on ictal unilateral eye blinking (UEB) as a lateralizing sign in focal seizures. We identified two patients with UEB and propose a novel mechanism of UEB based on a review of the literature.

Materials and methods

We report on two patients with intractable focal epilepsy showing UEB among 269 consecutive patients undergoing noninvasive video-EEG monitoring from October 2011 to May 2013.

Results

Unilateral eye blinking was observed in 0.7% (two of 269) of our patients. Patient one had four focal seizures. Semiological signs in all of her seizures were impaired consciousness, bilateral eye blinking (BEB), and UEB on the right. During one seizure, BEB recurred after UEB with a higher blink frequency on the right. Patient two had ten focal seizures. Among them were one electrographic seizure and nine focal seizures with BEB (in 3/10) and UEB on the left (in 1/10 seizures, respectively). Both patients did not display any clonic activity of the face. In seizures with UEB, ictal EEG onset was observed over the ipsilateral frontotemporal region in both of the patients (over F8 in 2/4, Fp2-F8 in 1/4, Sp2-T2 in 1/4, and F7 in 1/1 seizures, respectively). Ictal pattern during UEB showed bilateral ictal activity (in 4/4) and ictal discharges over the ipsilateral frontal region (maximum over F3 in 1/1 seizure). Interictal EEG showed sharp waves over the same regions.

Discussion

Unilateral eye blinking was ipsilateral to the frontotemporal ictal EEG pattern in both patients. The asymmetric blink frequency during BEB in patient one leads to the hypothesis that ictal UEB is caused by contralateral blink inhibition due to activation in frontotemporal cortical areas and mediated by trigeminal fibers.

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.

Seizure semiology: its value and limitations in localizing the epileptogenic zone

Epilepsy surgery has become an important treatment option in patients with medically refractory epilepsy. The ability to precisely localize the epileptogenic zone is crucial for surgical success. The tools available for localization of the epileptogenic zone are limited. Seizure semiology is a simple and cost effective tool that allows localization of the symptomatogenic zone which either overlaps or is in close proximity of the epileptogenic zone. This becomes particularly important in cases of MRI negative focal epilepsy. The ability to video record seizures made it possible to discover new localizing signs and quantify the sensitivity and specificity of others. Ideally the signs used for localization should fulfill these criteria; 1) Easy to identify and have a high inter-rater reliability, 2) It has to be the first or one of the earlier components of the seizure in order to have localizing value. Later symptoms or signs are more likely to be due to ictal spread and may have only a lateralizing value. 3) The symptomatogenic zone corresponding to the recorded ictal symptom has to be clearly defined and well documented. Reproducibility of the initial ictal symptoms with cortical stimulation identifies the corresponding symptomatogenic zone. Unfortunately, however, not all ictal symptoms can be reproduced by focal cortical stimulation. Therefore, the problem the clinician faces is trying to deduce the epileptogenic zone from the seizure semiology. The semiological classification system is particularly useful in this regard. We present the known localizing and lateralizing signs based on this system.

Detection of temporal lobe seizures and identification of lateralisation from audified EEG

OBJECTIVE

To investigate the accuracy of human listeners in identifying epileptic seizures and seizure lateralisation from audified EEG signals.

METHODS

EEG data from 17 temporal lobe epilepsy patients (9 male, 8 female; aged 23-55) was converted to audio format by 60× time compression. Using a subset of 19% of the data, five auditory participants (2 female, 3 male; aged 23-58) were trained to identify seizures and their lateralisation by listening to audified EEG signals from difference electrodes P3-T5 and P4-T6. Following training, seizure detection performance of the auditory participants was tested using the remaining data.

RESULTS

Allowing a 5s auditory time margin for successful detection, the mean sensitivity of the five auditory participants was 89.6% (SD 8.3%) with a false detection rate of only 0.0068/h (SD 0.0077/h). The mean accuracy of seizure lateralisation identification was 77.6% (SD 7.1%).

CONCLUSIONS

With a limited amount of training, humans can detect seizures and seizure lateralisation from audified EEG signals of electrodes P3-T5 and P4-T6 with accuracy comparable to visual assessment of full EEG traces (21 electrodes) by an expert encephalographer.

SIGNIFICANCE

A more efficient and accurate clinical tool for assessing EEG data based on audification may be developed, which will improve diagnosis and treatment of epilepsy.

Psychogenic non-epileptic seizures: a challenging entity

Psychogenic non-epileptic seizures (PNES) are commonly encountered in neurologic practice. They are often misdiagnosed as epileptic seizures and treated as such for several years before a correct diagnosis is established. Such a misdiagnosis has the potential to expose patients to undue risk through several anti-epileptic drugs (AEDs). Patients are also affected in other ways, such as by financial consequences and the limitation of certain daily activities. In this review, we present the contemporary opinion of PNES with attention to clinically relevant salient features and management strategies.

The correlation between ictal semiology and magnetoencephalographic localization in frontal lobe epilepsy

OBJECTIVE

The aim of this study was to investigate the correlation of ictal semiology with localization and/or lateralization by magnetoencephalography (MEG).

METHODS

Seven patients from the Neurology Department of the University Hospital Erlangen who underwent resective surgery for frontal lobe epilepsy (FLE) with an Engel 1a outcome were investigated retrospectively. MEG localizations were classified according to five compartments (separate or combined) of the frontal lobe: frontal basal (FB), frontal lateral (FL), frontal polar (FP), frontal mesial (FM), and frontal precentral (FPr). On the basis of previous studies that investigated the value of ictal semiology in localization and lateralization, we compared the experiential localization and/or lateralization of the epileptogenic region deduced from ictal semiology, that is, both seizure history and ictal video/EEG monitoring, with MEG localization.

RESULTS

It is easier to determine lateralization than localization from ictal semiology because of the variety of signs and fast propagation in FLE. All of the patients had specific MEG localizations according to favorable postoperative outcome. Three patients had MEG foci associated with ictal semiology; in another four, the MEG localization was adjacent to the estimated area suggested by ictal semiology. Head version signs could be observed in all compartments of the frontal lobe: clonic in FB and FP areas; postural in FPr, FL, and FM areas; hypermotor in FB, FP, FPr, and FM areas; sensation aura in FB, FL, and FM areas; and automatisms in FP, FPr, and FL areas. All patients had concordant lateralizing and limited valuable locating information from ictal semiology, but no complete correlation with MEG foci.

CONCLUSION

Ictal semiology may indicate the involvement of a symptomatogenic brain region during a seizure, but extent of seizure onset in central motor or sensorimotor area is not reliable enough to indicate the seizure onset zone and favorable postoperative outcome in FLE. MEG provided specific localization of epileptic activity in a FLE compartment, and indicated the relationship between epileptogenic region and lesion. MEG can complement ictal semiology in establishing a noninvasive focal localization hypothesis.

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.

Longitudinal Change in Outcome of Frontal Lobe Epilepsy Surgery

BACKGROUND:

Although the outcome of epilepsy surgery changes with time, few studies have considered longitudinal changes after frontal lobe epilepsy (FLE) surgery.

OBJECTIVE:

To assess the longitudinal changes after FLE surgery.

METHODS:

Resection of the seizure onset zone was performed in 76 patients with FLE. Invasive monitoring was performed in 56 of these 76. Awake craniotomy was performed in 43 of the 76 patients. More than 50% of patients were followed up for at least 7 years. The mean follow-up was 81 months.

RESULTS:

For all patients, the seizure-free rate was 79% at 6 months, 64% at 1 year, 55% at 2 years, and 55% at 7 years. For patients with cortical dysplasia, the seizure-free rate was 72% at 6 months, 53% at 1 year, 51% at 2 years, and 46% at 7 years. For patients with tumor, the seizure-free rate was 89% at 6 months, 83% at 1 year, 83% at 2 years, and 74% at 7 years. Patients with tumor showed better outcome than those with cortical dysplasia (P = .04). Although the overall seizure-free rate became stable after 2 years, individual status changed for up to 5 years. Seizures recurred in 11 patients within 1 year (early recurrence) and in 12 patients by 1 to 5 years (late recurrence). Antiepileptic drug (AED) medication was adjusted in all patients with recurrence. Patients with late recurrence had a more favorable response (Engel class I or II) than early recurrence (P < .01).

CONCLUSION:

The overall seizure outcome changes mostly during the first year. However, individual seizure status changes for up to 5 years. The outcome of late recurrence is favorable to AED adjustment.

EEG topography-specific BOLD changes: a continuous EEG-fMRI study in a patient with focal epilepsy

Blood oxygenation level dependent (BOLD) response related to interictal activity was evaluated in a patient with post-traumatic focal epilepsy at repeated continuous electroencephalogram (EEG)-functional magnetic resonance imaging examinations. Lateralized interictal EEG activity induced a main cluster of activation co-localized with the anatomical lesion. Spreading of EEG interictal activity to both frontal lobes evoked bilateral clusters of activation indicating that topography of BOLD response might depend on the spatial distribution of epileptiform activity.

Asymmetric seizure termination in primary and secondary generalized tonic-clonic seizures

PURPOSE

In temporal lobe epilepsies an asymmetric termination (AST) of the clonic phase of secondary generalized tonic-clonic seizures (sGTCS) reliably lateralizes the side of seizure onset. The last clonic activity occurs ipsilateral to the side of the seizure onset zone. We compared the prevalence and lateralizing value of AST in sGTCS of frontal and temporal lobe origin as well as in primary generalized tonic-clonic seizures (pGTCS).

METHODS

We analyzed 177 seizures in 84 consecutive patients. Forty-one patients had temporal lobe epilepsy (TLE), 24 frontal lobe epilepsy (FLE), and 19 had nonfocal (primary) generalized epilepsies (GE). All patients underwent intensive video-EEG (electroencephalography) monitoring, high-resolution magnetic resonance imaging (MRI), neuropsychological testing, and single photon emission computed tomography/positron emission tomography (SPECT/PET) when feasible. Two investigators blinded for diagnosis, EEG, and imaging data assessed frequency and side of the last clonic jerk.

RESULTS

AST occurred in 63% of patients with TLE (47% of seizures), in 71% with FLE (60% of seizures), and in 42% with GE (21% of seizures). These results were not significant for patients, but significant for seizures in TLE versus GE and in FLE versus GE (p < 0.001). The positive predictive value (PPV) for the side of seizure onset was 74% (p = 0.003) in TLE and 75% (p = 0.008) in FLE.

DISCUSSION

AST in sGTCS lateralizes the side of seizure onset in TLE and in FLE to the ipsilateral hemisphere with a high PPV. However, AST was also observed in GE. Therefore, asymmetric clinical signs should not inevitably lead to the assumption of focal epilepsy syndromes.

Ictal vocalizations occur more often in temporal lobe epilepsy with dominant (left-sided) epileptogenic zone

OBJECTIVE

To investigate the lateralization value of ictal vocalizations in temporal lobe epilepsy (TLE).

METHODS

We reviewed video-recordings of 97 patients who had undergone presurgical evaluation programs with video-EEG (electroencephalography)-recorded complex partial seizures (CPS) and high-resolution magnetic resonance imaging (MRI). All patients had surgery due to TLE and became seizure-free. In 57 patients, determination of speech dominance was necessary by using Wada tests or functional MRI (fMRI). To reevaluate the archived seizures, we reviewed one to three consecutively recorded CPS of each patient. Altogether 223 archived seizures were analyzed. Ictal vocalization was considered to be present in a particular patient if it occurred in at least one of the recorded seizures.

RESULTS

Ictal vocalizations occurred in 22 patients. They occurred in 37% of left-sided and in 11% of right-sided patients with TLE (p = 0.003). In patients with determined speech lateralization, ictal vocalizations occurred in 37% of the dominant and in 14% in patients with nondominant epileptogenic zone (p = 0.04). In patients with ictal vocalizations, epilepsy began at age 8.7 +/- 6, whereas in the remaining patients, epilepsy started at age 14.0 +/- 9 (p = 0.017). Logistic regression showed that both hemispheric dominance and age at onset were independently associated with pure ictal vocalization (PIV).

CONCLUSIONS

Ictal vocalization is a frequent phenomenon, occurring in 23% of patients with TLE. It is more often associated with left-sided and early onset TLE. Our results may improve the lateralization of the epileptogenic zone and suggest that nonspeech vocalizations in humans are related to the dominant (left-sided) hemisphere. Our study is a further argument that there are different subtypes of TLE depending on the age at onset.