Lateralizing value of epileptic nystagmus

Epileptic nystagmus is a relatively rare clinical seizure presentation. The direction is usually determined by the fast component of the eye movement. We retrospectively reviewed 1838 consecutive patients admitted to the Epilepsy Monitoring Unit at Cleveland Clinic and identified 9 patients (0.5%) with epileptic nystagmus. Only two of them were adults. The direction of the nystagmus was contralateral to the epileptogenic zone in all patients. In contrast, eye version was seen ipsiversive to the epileptic nystagmus in four of the six patients in whom both signs were observed. Epileptic nystagmus is a helpful lateralizing sign, particularly in pediatric patients.     

Tonic seizures: their significance for lateralization and frequency in different focal epileptic syndromes

PURPOSE: To determine whether the clinical features of tonic seizures (TSZ) are useful for lateralization of epileptic syndromes and the differential diagnosis of focal epileptic syndromes. METHODS: From a group of 481 patients, 123 patients with TSZ (44 females; mean age, 22.9 years; mean age at onset, 7 years; mean duration of epilepsy, 16 years) were selected. A total of 1595 epileptic seizures, documented during videoelectroencephalographic monitoring, were analyzed. Patients who had had surgery for epilepsy previously were excluded. Seizures were classified using a semiological seizure classification. Epilepsy syndromes were classified using all test data (electroencephalography, magnetic resonance imaging, computed tomography, positron emission tomography, and single-photon emission tomography). Data were compared using chi2 analysis or the Fisher exact test. RESULTS: More patients with TSZ had extratemporal than temporal lobe epilepsies (79% vs. 1.7%; p < 0.0001) among those with an epilepsy localized to one lobe (n = 306). In the 123 patients, TSZ were part of 170 different seizure evolutions. Seizure evolutions began with TSZ as the first seizure type more often in patients with frontal lobe epilepsy (FLE) compared with patients with parieto-occipital lobe epilepsy (POLE) (40% in POLE vs. 67% in FLE; p < 0.05). In contrast, TSZ in POLE were more likely to be preceded by auras (50% in POLE vs. 26% in FLE; p < 0.05). TSZ were bilateral in 129 (76%) and unilateral in 41 (24%) seizure evolutions. Unilateral TSZ correctly lateralized the epilepsy syndrome to the contralateral hemisphere. CONCLUSION: Analysis of seizure semiology and evolution in patients with TSZ is helpful for differentiating between focal epilepsies of temporal, frontal, and parieto-occipital origin. Unilateral TSZ provide useful information for the lateralization of the epileptic syndrome.     

神经外科患者癫痫反复发作处理分析

目的 探讨神经外科患者出现癫痫反复发作的临床特点、处理原则与方法.方法 回顾性分析沈阳军区总医院神经外科自2011年1月至6月收治的9例癫痫反复发作患者的临床资料,分析其加重的原因、发作特点及治疗方法和结果.结果 9例患者中3例合并胶质瘤、1例蛛网膜囊肿、1例海绵状血管瘤、1例脑软化灶;7例有癫痫病史,2例既往无癫痫病史;7例为额叶癫痫,2例颞叶癫痫.癫痫发作加重的原因:减药3例,新诊断的脑肿瘤2例,手术(颅内电极置入术)1例,原因不明3例.癫痫发作类型包括部分性发作与全面性发作,发作频率从间隔3min至间隔数小时发作一次.患者经给予多种抗癫痫药物联合用药治疗,包括口服与注射给药,癫痫得到控制,其中添加左乙拉西坦口服有较好的疗效.结论 神经外科患者出现癫痫反复发作多呈药物难治性,发作不易控制,其处理应使用对部分性癫痫发作有较好疗效的多种抗癫痫药物联合用药,剂量应高于常规初始剂量,包括静脉注射及肌注给药,以尽快控制癫痫发作.左乙拉西坦因口服吸收快、起效迅速及有较好的抗癫痫作用,对癫痫反复发作有较好的疗效.     

Topographic movie of intracranial ictal high-frequency oscillations with seizure semiology: epileptic network in Jacksonian seizures

Purpose: We developed a technique to produce images of dynamic changes in ictal high‐frequency oscillations (HFOs) >40 Hz recorded on subdural electroencephalography (EEG) that are time‐locked to the ictal EEG and ictal semiology video. We applied this technique to Jacksonian seizures to demonstrate ictal HFO propagation along the homunculus in the primary sensory‐motor cortex to visualize the underlying epileptic network. Methods: We analyzed intracranial ictal EEGs from two patients with intractable Jacksonian seizures who underwent epilepsy surgery. We calculated the degrees of increase in amplitude within 40–80, 80–200, and 200–300 Hz frequency bands compared to the interictal period and converted them into topographic movies projected onto the brain surface picture. We combined these data with the ictal EEGs and video of the patient demonstrating ictal semiology. Key Findings: The ictal HFOs began in the sensory cortex and appeared concomitantly with the sensory aura. They then propagated to the motor cortex at the same time that focal motor symptoms evolved. As the seizure progressed, the ictal HFOs spread or reverberated in the rolandic region. However, even when the seizure became secondarily generalized, the ictal HFOs were confined to the rolandic region. In both cases, there was increased amplitude of higher frequency bands during seizure initiation compared to seizure progression. Significance: This combined movie showed the ictal HFO propagation corresponding to the ictal semiology in Jacksonian seizures and revealed the epileptic network involved in seizure initiation and progression. This method may advance understanding of neural network activities relating to clinical seizure generation and propagation.     

The localizing value of epileptic auras: pitfalls in semiology and involved networks

A more complete understanding of the epileptic aura represents an important challenge for localizing the epileptogenic zone and understanding brain networks. This review re‐visits the localizing value of the epileptic aura, focusing on clinical pitfalls in epileptogenic zone detection and the importance of defining functional connectivity. We review the role of network node activation or alteration and its relationship to hub activation.     

Seizure ending signs in patients with dyscognitive focal seizures*

Aim. Signs indicating the end of a focal seizure with loss of awareness and/or responsiveness but without progression to focal or generalized motor symptoms are poorly defined and can be difficult to determine. Not recognizing the transition from ictal to postictal behaviour can affect seizure reporting accuracy by family members and may lead to delayed or a lack of examination during EEG monitoring, erroneous seizure localization and inadequate medical intervention for prolonged seizure duration. Methods. Our epilepsy monitoring unit database was searched for focal seizures without secondary generalization for the period from 2007 to 2011. The first focal seizure in a patient with loss of awareness and/or responsiveness and/or behavioural arrest, with or without automatisms, was included. Seizures without objective symptoms or inadequate video‐EEG quality were excluded. Results. A total of 67 patients were included, with an average age of 41.7 years. Thirty‐six of the patients had seizures from the left hemisphere and 29 from the right. All patients showed an abrupt change in motor activity and resumed contact with the environment as a sign of clinical seizure ending. Specific ending signs (nose wiping, coughing, sighing, throat clearing, or laughter) were seen in 23 of 47 of temporal lobe seizures and 7 of 20 extra‐temporal seizures. Conclusions. Seizure ending signs are often subtle and the most common finding is a sudden change in motor activity and resumption of contact with the environment. More distinct signs, such as nose wiping, coughing or throat clearing, are not specific to temporal lobe onset. A higher proportion of seizures during sleep went unexamined, compared to those during wakefulness. This demonstrates that seizure semiology can be very subtle and arousals from sleep during monitoring should alert staff. Patient accounts of seizure frequency appear to be unreliable and witness reports need to be taken into account. [Published with video sequences]     

A method for detecting epileptic seizures.

A simple instrument for detecting seizures is described. Vibrations of the bed due to movements of the patient were converted to electrical oscillations by movement of a loudspeaker coil in reversed mode as transducer. To distinguish between normal movements and those caused by a seizure, three criteria were used--the amplitude of the oscillations, the time interval between them, and the duration of a burst of oscillations, each parameter compared with a reference value for each patient.     

Lateralizing value of behavioral arrest in patients with temporal lobe epilepsy

Analysis of ictal semiology is essential to presurgical evaluation of patients with epilepsy. To assess the localizing value of behavioral arrest in temporal lobe epilepsy (TLE), we analyzed 107 video/EEG monitoring-documented seizures of 107 adult patients with TLE for a set of defined seizure phenomena with respect to frequency and sequence of occurrence in relation to epileptogenic (mesial vs extramesial, left vs right) origin. Behavioral arrest was observed more frequently in left-sided temporal seizures: 25.7% of left-sided mesial seizures and 25.0% of left-sided extramesial seizures exhibited behavioral arrest, whereas only 3.4% of right-sided mesial seizures and 10.5% of right-sided extramesial seizures were associated with behavioral arrest. In addition, occurence of behavioral arrest within the sequence of seizure phenomena was remarkably consistent, being observed mainly as the first apparent feature of seizure onset. Thus, behavioral arrest is a valuable early indicator of a left-sided temporal epileptogenic focus in adult patients with TLE.     

Loss of responsiveness in psychogenic non‐epileptic seizures

Aims : The aim of this study was to investigate the frequency of loss of responsiveness (LOR) in patients with psychogenic non‐epileptic seizures (PNES) and to characterize the patients' clinical variables that may be associated with such a manifestation. Methods : In this retrospective study, all patients with documented PNES, who were investigated at Shiraz Comprehensive Epilepsy Center at Shiraz University of Medical Sciences, from 2008 to 2018, were investigated. Results : During the study period, data was available for 324/325 patients with PNES. In total, 275 patients (85%) reported LOR during their seizures, but this was not the case for 49 patients (15%). The model, generated by regression analysis, was shown to be significant (p=0.0001) and LOR could be predicted in 84% of the patients. Closed eyes during seizures (OR: 4.4; 95% CI: 2.101–9.235; p=0.0001) and seizure‐associated injury (OR: 3.5; 95% CI: 1.402–8.686; p=0.007) were significantly associated with LOR based on the model. Conclusion : Patients with PNES may frequently report LOR, which is significantly associated with seizure‐related injuries. Therefore, it is important to apply appropriate management strategies for patients with PNES and LOR in order to prevent or decrease the possibility of any associated consequences, including ictal injury.     

Predictive value of EEG findings at control of epileptic spasms for seizure relapse in patients with West syndrome

PurposeTo evaluate the prognostic importance of electroencephalography (EEG) findings at cessation of epileptic spasms for seizure outcome.MethodsWe reviewed 71 children with West syndrome (cryptogenic 14) who had obtained control of epileptic spasms with initial treatment (adrenocorticotropic hormone (ACTH) 37, high-dose vitamin B₆ 2, and antiepileptic drugs 32). According to the EEG findings at control of epileptic spasms, the subjects were divided into three groups: normal group (no epileptic activity, n = 12), abnormal group (residual epileptic activity without hypsarrhythmia, n = 53), and hypsarrhythmic group (persisting hypsarrhythmia, n = 6).ResultsOverall, 47 (66%) of the 71 patients (cryptogenic 4) had experienced relapses of seizures (epileptic spasms 23 and focal seizure 24) after initial control of epileptic spasms. Within symptomatic cases, seizure relapse rate varied widely from 0% (Down syndrome) to 100% (tuberous sclerosis), depending on underlying causes. Seizure relapse depended on the EEG findings at control of epileptic spasms. The normal group had a significantly lower seizure relapse rate (17%) in comparison with the abnormal group (75%), the hypsarrhythmic group (83%), and the epileptiform (abnormal plus hypsarrhythmic, 76%) group. No significant difference in seizure relapse rate was observed between non-hypsarrhythmic (normal plus abnormal, 65%) and hypsarrhythmic groups. At the last follow-up, normal group children also showed a favorable seizure prognosis (seizure control 100%).ConclusionsA favorable seizure prognosis is associated with the disappearance of epileptic activity, but not the resolution of hypsarrhythmic pattern on EEG at control of epileptic spasms. We suggest that effective treatment for West syndrome should produce both cessation of epileptic spasms and disappearance of epileptic activity on EEG.     

卒中后继发癫痫患者常规与动态脑电图检查的比较分析

目的研究卒中后继发癫痫患者常规脑电图(electroencephalography,EEG)与动态脑电图(ambulatory electroencephalography,AEEG)的特点。方法观察40例急性卒中后继发癫痫患者的病灶分布、范围、癫痫发作形式及频数,所有病例作EEG及AEEG检查,将检查结果分为正常、轻度异常、中度异常及重度异常进行统计分析。结果40例研究对象的病灶分布主要在颞叶、额叶及丘脑,癫痫发作类型主要为全面性强直阵挛发作。EEG检查异常的比率为47.5%,其中轻度异常占异常总数的52.6%,中度和重度异常占47.4%;AEEG检查异常的比率为80%,其中轻度异常占异常总数的12.5%,中度和重度异常占87.5%,AEEG较EEG检查的异常比率明显增高,具有统计学差异。结论AEEG可显著提高卒中后癫痫发作患者的脑电异常检出率,其检查结果对指导临床治疗具有一定的价值。     

Frequency-independent characteristics of high-frequency oscillations in epileptic and non-epileptic regions

Objective

The purpose of the presented study is to determine whether there are frequency-independent high-frequency oscillation (HFO) parameters which may differ in epileptic and non-epileptic regions.

Semiologic aspects of epileptic seizures in 31 patients with hypothalamic hamartoma

Purpose: Characterization of seizure semiology in patients with hypothalamic hamartoma (HH) based on video–electroencephalography (EEG) monitoring (VEM). Methods: We retrospectively analyzed seizure semiology of 31 patients (20 male, mean age 23.5 years) who underwent VEM at the University Hospitals Freiburg or Heidelberg, Germany. Inclusion criteria were magnetic resonance evidence of an HH, no prior surgical or radiosurgical treatment, and at least two video‐documented seizures. A total of 263 seizures were included (mean number of seizures/patient 8.5, range 2–10). To analyze age‐dependent changes in seizure semiology, patients were grouped into “children” (3–11 years, n = 5), “adolescents” (12–17 years, n = 4), and “adults” (≥18 years, n = 22). Results: According to patient history, gelastic seizures had occurred in all patients, in 74% as the initial seizure type at epilepsy onset. In VEM, epileptic laughter varied from facial grinning to intense contractions of the diaphragm and body shaking. Unilateral motor signs were seen ipsi‐ and contralaterally to the HH. Tonic seizures were frequent and did not depend on the state of vigilance. Children, in contrast to adults and adolescents, did not show secondarily generalized tonic–clonic seizures, the gelastic component was the dominating and initial semiologic element, and seizures were significantly shorter. Conclusion: Seizure semiology is highly variable and age dependent. This may reflect network modulations with different propagation of ictal activity and/or secondary epileptogenesis. Detailed knowledge about such changes may contribute to both earlier recognition of seizures during childhood and better assignment of seizure types to a hypothalamic origin.     

Ictal patterns of neocortical seizures monitored with intracranial electrodes: correlation with surgical outcome

PURPOSE: Numerous factors have been analyzed in attempts to predict the outcome of surgical resections in patients with neocortical epilepsy. We examined the correlation between surgical outcome and electrocorticographic features of neocortical ictal patterns. METHODS: Twenty six patients with neocortical epilepsy underwent monitoring with subdural grid electrodes before surgery. Ictal patterns were analyzed retrospectively and correlated with three types of outcome: seizure free, worthwhile improvement (>75% reduction of seizure frequency), and no worthwhile improvement. The duration of follow-up was 2-5 years. RESULTS: Ictal patterns were divided according to the size of epileptogenic zone (focal, regional, multifocal); velocity and type of seizure propagation (fast contiguous, slow contiguous, noncontiguous); pattern of the onset of ictal activity; part of the cortex involved in the origin of the seizure (frontal, frontocentroparietal, etc.). Spread to medial temporal structures (as assessed by subtemporal strips) also was evaluated in selected cases. Statistically significant correlation with surgical outcome (p = 0.026) was shown for only one variable: type of spread. Patients with slow spread (n = 8) demonstrated the best outcomes (five are seizure free), whereas patients with noncontiguous spread (n = 5) demonstrated the worst outcomes (four did not improve significantly). Patients with fast contiguous spread (n = 13) showed intermediate outcomes. CONCLUSIONS: Types of propagation of ictal neocortical activity correlate with surgical outcome. Analysis of ictal pattern during intracranial recordings may help to predict surgical outcome for neocortical epilepsy.     

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

PURPOSE: To quantitatively evaluate the lateralizing significance of ictal head movements of patients with temporal lobe epilepsy (TLE). METHODS: We investigated EEG-video recorded seizures of patients with TLE, in which the camera position was perpendicular to the head facing the camera in an upright position and bilateral head movement was recorded. Thirty-eight seizures (31 patients) with head movement in both directions were investigated. Ipsilateral and contralateral head movements were defined according to ictal EEG. Head movements were quantified by selecting the movement of the nose in relation to a defined point on the thorax (25/s) in a defined plane facing the camera. The duration of the head version was determined independently of the camera angle. The angle, duration, and angular speed of the head movements were computed and inter and intrasubject analyses were performed (Wilcoxon rank sum). RESULTS: Ipsilateral movement always preceded contralateral movement. The positive predictive value was 100% for movement in both directions. The duration of contralateral head version was significantly longer than ipsilateral head movement (6.4 +/- 4.1 s vs. 3.9 +/- 3.1 s, p<0.001). The angular speed of both movements was similar (15.5 +/- 12.1 deg/s vs. 17.3 +/- 13.0 deg/s). CONCLUSION: The quantitative analysis shows the importance of sequence in the seizure's evolution and duration, but not angular speed for correct lateralization of versive head movement. This quantitative method shows the high lateralizing value of ictal lateral head movements in TLE.     

Similar semiology of epileptic and psychogenic nonepileptic seizures recorded during stereo-EEG

We report two adolescents with refractory seizure disorders in whom both epileptic and psychogenic nonepileptic seizures (PNES) were recorded with intracerebral EEG. The ictal phenomenology of epileptic seizures (ES) and PNES, consisting of hypermotor attacks in the first patient and left-sided painful episodes in the second patient, proved remarkably similar in both cases, highlighting the difficulties which can arise with the distinction of epileptic seizures and PNES based on ictal phenomenology alone.     

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.