Lateralizing significance of quantitative analysis of head movements before secondary generalization of seizures of patients with temporal lobe epilepsy

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.

Lower limb automatism in surgically treated temporal lobe epilepsy patients: Clinical and electrophysiological features

Lower limb automatism has not been known well in temporal lobe epilepsy (TLE) patients. This study investigated the distribution of risk factors, EEG features, and pathology types in surgically treated TLE patients. We also made a comparison of this group to surgically treated TLE patients with isolated hand automatism. Twenty TLE patients with lower limb automatism (Group 1) and 20 TLE patients with isolated hand automatisms (Group 2) of similar age/sex distribution were enrolled in our study. Male/female ratio was 14/6 in both groups. Demographical characteristics, risk factors, pathology types and EEG features were compared between two groups. 15 and 8 patients out of Group 1 (75%) and Group 2 (40%) respectively, were undergone right-sided surgery. Ipsilateral lower limb automatism was seen in 80% of patients. The age of epilepsy onset was earlier in patients with lower limb automatism (p = 0.02). There was no significant difference between the groups in terms of the risk factors and other demographical characteristics. Although, EEG features were not different, onset of ictal EEG changes in the first 10 seconds were seen less frequently in Group 1(6 vs 9 patients) (p = 0.31). Hippocampal sclerosis as a pathology type was detected in 11 patients (55%) of Group 1, whereas in 16 patients (80%) of Group 2. TLE patients with lower limb automatism have an earlier age of epilepsy onset and the onset of ictal EEG changed in the first 10 seconds of clinical seizure and pure HS pathology was rarer than in TLE patients with hand automatisms. Further studies are needed to shed more light on the pathophysiology of lower extremity automatisms in TLE patients.

NeuroKinect: A Novel Low-Cost 3Dvideo-EEG System for Epileptic Seizure Motion Quantification

Epilepsy is a common neurological disorder which affects 0.5-1% of the world population. Its diagnosis relies both on Electroencephalogram (EEG) findings and characteristic seizure-induced body movements--called seizure semiology. Thus, synchronous EEG and (2D)video recording systems (known as Video-EEG) are the most accurate tools for epilepsy diagnosis. Despite the establishment of several quantitative methods for EEG analysis, seizure semiology is still analyzed by visual inspection, based on epileptologists' subjective interpretation of the movements of interest (MOIs) that occur during recorded seizures. In this contribution, we present NeuroKinect, a low-cost, easy to setup and operate solution for a novel 3Dvideo-EEG system. It is based on a RGB-D sensor (Microsoft Kinect camera) and performs 24/7 monitoring of an Epilepsy Monitoring Unit (EMU) bed. It does not require the attachment of any reflectors or sensors to the patient's body and has a very low maintenance load. To evaluate its performance and usability, we mounted a state-of-the-art 6-camera motion-capture system and our low-cost solution over the same EMU bed. A comparative study of seizure-simulated MOIs showed an average correlation of the resulting 3D motion trajectories of 84.2%. Then, we used our system on the routine of an EMU and collected 9 different seizures where we could perform 3D kinematic analysis of 42 MOIs arising from the temporal (TLE) (n = 19) and extratemporal (ETE) brain regions (n = 23). The obtained results showed that movement displacement and movement extent discriminated both seizure MOI groups with statistically significant levels (mean = 0.15 m vs. 0.44 m, p<0.001; mean = 0.068 m(3) vs. 0.14 m(3), p<0.05, respectively). Furthermore, TLE MOIs were significantly shorter than ETE (mean = 23 seconds vs 35 seconds, p<0.01) and presented higher jerking levels (mean = 345 ms(-3) vs 172 ms(-3), p<0.05). Our newly implemented 3D approach is faster by 87.5% in extracting body motion trajectories when compared to a 2D frame by frame tracking procedure. We conclude that this new approach provides a more comfortable (both for patients and clinical professionals), simpler, faster and lower-cost procedure than previous approaches, therefore providing a reliable tool to quantitatively analyze MOI patterns of epileptic seizures in the routine of EMUs around the world. We hope this study encourages other EMUs to adopt similar approaches so that more quantitative information is used to improve epilepsy diagnosis.

Eye movements differ between ictal ipsilateral and contralateral head turning

PURPOSE

This study evaluated the relation of head and eye movements during ictal ipsilateral and contralateral head turning in patients with focal epilepsies with regard to lateralization of the epileptogenic zone.

METHODS

We reviewed our database and identified patients with ictal head turning ipsilateral and contralateral to the seizure onset as defined by ictal EEG. Twenty-seven seizures of 19 consecutive patients with ipsilateral and 40 seizures of 32 patients with contralateral head turning were investigated. Twenty-four patients had temporal lobe epilepsy (TLE), and 27 patients had extratemporal or multifocal epilepsy.

KEY FINDINGS

Eye movement in the same direction preceded contralateral head turning in 90% (36 of 40 seizures) of the seizures, but this was the case in only 33% (9 of 27 seizures) of the ipsilateral ictal head turning. In contrary, head turning preceded the eye movements in 67% (18 of 27 seizures) of the ipsilateral ictal head turning and in only 10% of the contralateral head turning (p < 0.001). The results were similar in TLE and FLE.

SIGNIFICANCE

The sequence of head and eye movements is different in ictal ipsilateral and contralateral head turning movements which likely reflects different spread patterns of epileptic activity associated with activation of different generators. The analysis of eye movements adds to the lateralization of ictal head movements.

An evaluation of lateralizing signs in patients with temporal lobe epilepsy

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

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.

Vision-based motion detection, analysis and recognition of epileptic seizures--a systematic review

The analysis of human motion from video has been the object of interest for many application areas, these including surveillance, control, biomedical analysis, video annotation etc. This paper addresses the advances within this topic in relation to epilepsy, a domain where human motion is with no doubt one of the most important elements of a patient's clinical image. It describes recent achievements in vision-based detection, analysis and recognition of human motion in epilepsy for marker-based and marker-free systems. An overview of motion-characterizing features extracted so far is presented separately. The objective is to gain existing knowledge in this field and set the route marks for the future development of an integrated decision support system for epilepsy diagnosis and disease management based on automated video analysis. This review revealed that the quantification of motion patterns of selected epileptic seizures has been studied thoroughly while the recognition of seizures is currently in its beginnings, but however feasible. Moreover, only a limited set of seizure types have been analyzed so far, indicating that a holistic approach addressing all epileptic syndromes is still missing.

Increased metallothionein I/II expression in patients with temporal lobe epilepsy

In the central nervous system, zinc is released along with glutamate during neurotransmission and, in excess, can promote neuronal death. Experimental studies have shown that metallothioneins I/II (MT-I/II), which chelate free zinc, can affect seizures and reduce neuronal death after status epilepticus. Our aim was to evaluate the expression of MT-I/II in the hippocampus of patients with temporal lobe epilepsy (TLE). Hippocampi from patients with pharmacoresistant mesial temporal lobe epilepsy (MTLE) and patients with TLE associated with tumor or dysplasia (TLE-TD) were evaluated for expression of MT-I/II, for the vesicular zinc levels, and for neuronal, astroglial, and microglial populations. Compared to control cases, MTLE group displayed widespread increase in MT-I/II expression, astrogliosis, microgliosis and reduced neuronal population. In TLE-TD, the same changes were observed, except that were mainly confined to fascia dentata. Increased vesicular zinc was observed only in the inner molecular layer of MTLE patients, when compared to control cases. Correlation and linear regression analyses indicated an association between increased MT-I/II and increased astrogliosis in TLE. MT-I/II levels did not correlate with any clinical variables, but MTLE patients with secondary generalized seizures (SGS) had less MT-I/II than MTLE patients without SGS. In conclusion, MT-I/II expression was increased in hippocampi from TLE patients and our data suggest that it is associated with astrogliosis and may be associated with different seizure spread patterns.

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.

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.

Semiology of epileptic seizures: a critical review

Epileptic seizures are characterized by a variety of symptoms. Their typical semiology served for a long time as the major tool to classify epilepsy syndromes. The signs and symptoms of epileptic seizures include the following spheres: sensorial sphere, consciousness, motor and autonomic spheres. Most seizures involve more than one sphere, however, some like for instance aura (sensorial sphere) or dialeptic seizures (consciousness) involve only one sphere. The predominant clinical features of a seizure determines the seizure classification. The following review gives an introduction into the semiological seizure classification. This approach enables us to better identify the epileptogenic zone of our patients and to choose the most effective medical or surgical treatment.

Quantitative and trajectory analysis of movement trajectories in supplementary motor area seizures of frontal lobe epilepsy

The objectives of this study were to quantitatively analyze the movement trajectories of four types of supplementary motor area (SMA) seizures (hyperkinetic, tonic posturing, fencing posture, tonic head turning), and to compare the movement trajectories of SMA seizures with those of temporal lobe seizures and psychogenic nonepileptic seizures. Ten video/EEG recordings of each type of seizure were obtained. Imaging data collected by video/EEG monitoring were transformed into a digital matrix with image processing software and then transformed into a movement trajectory curve with MATLAB 6.5 software. From these movement trajectories, amplitude, frequency, proximal/distal limb amplitude ratios, and shoulder/abdominal amplitude ratios measurements were calculated. One-way ANOVA revealed statistically significant differences in average amplitude, as well as proximal/distal limb amplitude ratios, in SMA seizures when compared with those of temporal lobe seizures and psychogenic nonepileptic seizures. This study proved the feasibility of quantitative analysis of SMA seizures and suggests it should be further evaluated for its capability to distinguish different seizure semiologies for the diagnosis of epilepsy.