Brain diffusion after single seizures

PURPOSE: Diffusion-weighted magnetic resonance imaging (DWI) after focal status epilepticus has demonstrated focal alterations of the apparent diffusion coefficient (ADC) in the epileptogenic zone. We hypothesized that localized dynamic alterations of brain diffusion during the immediate postictal state will be detectable by serial DWI and correlate with the epileptogenic zone. METHODS: Nine adult patients (four men, five women) with medically intractable epilepsy were prospectively examined with a total of 25 DWI scans taken 2-210 min after a seizure. RESULTS: The interictal ADC was significantly (p < 0.05) elevated in the ictogenic hippocampus in all patients with temporal lobe epilepsy. The following postictal changes of the ADC were seen: (a) decreases by maximally 25-31%, which were most pronounced in the epileptogenic zone (n = 2); (b) generalized ADC changes after generalized seizures (n = 1) or prolonged complex partial seizures (n = 2); (c) no major changes after short-lived seizures or if the time to first DWI scan was >15 min or both (n = 3); and (d) widespread bilateral ADC increases after a flumazenil-induced seizure (n = 1). CONCLUSIONS: ADC changes seen during serial postictal DWI are complex and appear to reflect origin and spread of the preceding seizure. A delineation of the epileptogenic zone appears to be possible only in complex-partial seizures of >60 s duration that do not secondarily generalize.     

Brain structure and aging in chronic temporal lobe epilepsy

Purpose: To characterize differences in brain structure and their patterns of age‐related change in individuals with chronic childhood/adolescent onset temporal lobe epilepsy compared with healthy controls. Methods: Subjects included participants with chronic temporal lobe epilepsy (n = 55) of mean childhood/adolescent onset and healthy controls (n = 53), age 14–60 years. Brain magnetic resonance imaging (MRI) studies (1.5 T) were processed using FreeSurfer to obtain measures of lobar thickness, area, and volume as well as volumes of diverse subcortical structures and cerebellum. Group differences were explored followed by cross‐sectional lifespan modeling as a function of age. Key Findings: Anatomic abnormalities were extensive in participants with chronic temporal lobe epilepsy including distributed subcortical structures (hippocampus, thalamus, caudate, and pallidum), cerebellar gray and white matter, total cerebral gray and white matter; and measures of cortical gray matter thickness, area, or volume in temporal (medial, lateral) and extratemporal lobes (frontal, parietal). Increasing chronologic age was associated with progressive changes in diverse cortical, subcortical, and cerebellar regions for both participants with epilepsy and controls. Age‐accelerated changes in epilepsy participants were seen in selected areas (third and lateral ventricles), with largely comparable patterns of age‐related change across other regions of interest. Significance: Extensive cortical, subcortical, and cerebellar abnormalities are present in participants with mean chronic childhood/adolescent onset temporal lobe epilepsy implicating a significant neurodevelopmental impact on brain structure. With increasing chronologic age, the brain changes occurring in epilepsy appear to proceed in a largely age‐appropriate fashion compared to healthy controls, the primary exception being age‐accelerated ventricular expansion (lateral and third ventricles). These cumulative structural abnormalities appear to represent a significant anatomic burden for persons with epilepsy, the consequences of which remain to be determined as they progress into elder years.     

Can postictal memory predict postoperative memory in patients with temporal lobe epilepsy?

We investigated the contribution of postictal memory testing for lateralizing the epileptic focus and predicting memory outcome after surgery for temporal lobe epilepsy (TLE). Forty‐five patients with TLE underwent interictal, postictal, and postoperative assessment of verbal and nonverbal memory. Surgery consisted of anterior temporal lobectomy (36), selective isolated amygdalohippocampectomy (6), or amygdalohippocampectomy coupled to lesionectomy (3). Postictal and postoperative but not interictal memory were significantly lower in left TLE than in right TLE. Nonverbal memory showed no significant difference in left TLE versus right TLE in all conditions. Postictal memory was significantly correlated with postoperative memory, but the effect disappeared when the lateralization of the focus was considered. Postictal verbal memory is a useful bedside tool that can help lateralize the epileptic focus. Larger studies are needed to further estimate its predictive value of the postoperative outcome.     

Toothbrush-thinking seizures

Seizures associated with toothbrushing have been reported in patients with precentral or postcentral partial epilepsy. Seizures precipitated by thinking have been described in patients with idiopathic generalized epilepsy. We report a patient with intractable partial epilepsy in which seizures were induced both by toothbrushing, and by seeing or thinking about toothbrush and toothpaste. Video-EEG analysis revealed a left temporal lobe origin for these reflex seizures. We discuss how complex multimodal stimuli may trigger these reflex seizures.     

Postictal Nosewiping Lateralizes and Localizes to the Ipsilateral Temporal Lobe

Summary: Purpose: We observed many patients with temporal lobe epilepsy (TLE) wiping their nose postictally, usually with the hand ipsilateral to their seizure focus. We wished to determine if this had lateralizing or localizing significance. Methods: We retrospectively studied 87 patients: 47 with unilateral TLE defined by successful surgical outcome [30 with medial TLE (MTLE) and 17 with neocortical TLE (neoTLE)]; and 40 with extratemporal epilepsy (ExTLE). Videotapes of 319 complex partial seizures (CPS) without generalization were reviewed by 1 neurologist, blinded to patient identity, who recorded each episode of nosewiping and the hand with which it was performed. Results: With regard to localizing potential, postictal nosewiping (PINW) was significantly more common in patients with unilateral TLE than in those with ExTLE. In the TLE group, PINW within 60 s of electrographic seizure offset occurred in 60% of patients (28 of 47) and 43% of seizures (74 of 171). In the ExTLE group, PINW was noted in 33% of patients (13 of 40; p < O.05 as compared with TLE) and 15% of seizures (22 of 148; p < O.001). Similar results were obtained with PINW within 30 s of seizure offset. Although PINW was more frequent in MTLE than in neoTLE (67% of patients vs. 47%), this finding did not reach significance. With regard to lateralizing potential, in the TLE group, unilateral PINW (performed with a single hand only) within 60 s of seizure offset was observed in 53% of patients (25 of 47) and was performed with the hand ipsilateral to the seizure focus in 92% (23 of 25). Thirteen patients (9 with TLE) wiped their nose more than once with the same hand in a single seizure within 60 s of offset in 18 seizures; this was done with the hand ipsilateral to the seizure focus in all 18 instances (predictive value = 100%). Conclusions: PINW is more common in unilateral TLE, particularly MTLE, than in ExTLE. PINW performed exclusively with one hand occurs in ～50% of patients with TLE and is highly predictive (92%) of seizure onset ipsilateral to the hand used, especially when it occurs repetitively. We hypothesize that ictal activation of the central autonomic nervous system, particularly the amygdala, results in ictal nasal secretions and causes nosewiping as the patient regains awareness postictally. The ipsilateral hand is used due to contralateral neglect or weakness.     

Only certain antiepileptic drugs prevent seizures induced by pilocarpine

Seizures produced in rats by systemically administered pilocarpine (PILO) provide a model for studying the generation and spread of convulsive activity in the forebrain. PILO, 380 mg/kg, induces a sequence of behavioral and electroencephalographic alterations indicative of motor limbic seizures and status epilepticus which is followed by widespread damage to the limbic forebrain resembling that occurring subsequent to prolonged intractable seizures in humans. The present study was undertaken to determine whether clinically utilized antiepileptic drugs share an ability to suppress seizures and brain damage elicited by PILO in rats. Clonazepam, ED₅₀ 0.35 mg/kg (0.25–0.49), phenobarbital, 23.4 mg/kg (18.5–29.6), and valproic acid, 286 mg/kg (202–405), prevented the buildup of limbic seizures and protected against seizure-related brain damage. Pretreatment with trimethadione, 179 mg/kg (116–277), resulted in a moderate protection against PILO-induced seizures, whereas carbamazepine, 10–50 mg/kg, and diphenylhydantoin, 10–200 mg/kg, blocked neither convulsions nor brain damage produced by the drug. Surprisingly, ethosuximide, 196 mg/kg (141–272), and acetazolamide, 505 mg/kg (332–766), both lowered the threshold for seizures induced by PILO and converted a non-convulsant dose of PILO, 200 mg/kg, into a convulsant one. These results indicate that only certain anticonvulsant drugs elevate the threshold for PILO-induced seizures and prevent the occurrence of epilepsy-related brain damage. The resistance of seizures produced by PILO in rats to antiepileptic drugs reaffirms the clinically obvious lack of effective treatments for limbic convulsions.     

Violence and Epilepsy: A Close Relation Between Violence and Postictal Psychosis

Summary: Purpose: We investigated the incidence of well-directed violent behavior and suicide attempts in patients with temporal lobe epilepsy, with special attention to postictal psychosis.
Methods: We compared 57 episodes of postictal psychosis with 62 episodes of acute interictal (or alternative) psychosis and with 134 complex partial seizures. All patients were matched for age and for age at onset of seizures.
Results: The incidence of well-directed violent behavior against human beings was significantly higher (23%) during postictal psychotic episodes than during acute interictal episodes (5%) and postictal confusion (1%). Suicide attempts were also more frequent during postictal psychosis (7%) than during either acute interictal psychosis (2%) or postictal confusion (0%).
Conclusions: Our study showed that well-directed violent and self-destructive behavior was not a feature of epileptic psychosis in general but a specific hallmark of postictal psychosis.     

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%.     

Acute Psychosis During Intracranial EEG Monitoring: Close Relationship Between Psychotic Symptoms and Discharges in Amygdala

PURPOSE: This report examined the underlying mechanism of psychosis associated with epilepsy. METHODS: An adult patient with epilepsy manifesting acute psychosis during long-term EEG monitoring is presented, together with a literature review on this subject. RESULTS: A 25-year-old woman with intractable temporal lobe epilepsy developed acute psychosis while she underwent long-term intracranial EEG monitoring. After a clustering of seizures, she manifested psychotic symptoms including hallucination, stupor, and repeated fear. The transition of psychotic symptoms corresponded to the changes in frequency and morphology of seizure discharges restricted to the left amygdala. Improvement of psychosis coincided with disappearance of seizure discharges. CONCLUSIONS: This case confirmed a close relationship between psychotic symptoms and seizure discharges in the left amygdala. It is suggested that paroxysmal bombardment of the medial temporal lobe structure may be a pathogenetic factor of acute psychosis associated with epilepsy.     

Ipsilateral and contralateral MRI volumetric abnormalities in chronic unilateral temporal lobe epilepsy and their clinical correlates

PURPOSE: To assess the presence, extent, and clinical correlates of quantitative MR volumetric abnormalities in ipsilateral and contralateral hippocampus, and temporal and extratemporal lobe regions in unilateral temporal lobe epilepsy (TLE). METHODS: In total, 34 subjects with unilateral left (n = 15) or right (n = 19) TLE were compared with 65 healthy controls. Regions of interest included the ipsilateral and contralateral hippocampus as well as temporal, frontal, parietal, and occipital lobe gray and white matter. Clinical markers of neurodevelopmental insult (initial precipitating insult, early age of recurrent seizures) and chronicity of epilepsy (epilepsy duration, estimated number of lifetime generalized seizures) were related to magnetic resonance (MR) volume abnormalities. RESULTS: Quantitative MR abnormalities extend beyond the ipsilateral hippocampus and temporal lobe with extratemporal (frontal and parietal lobe) reductions in cerebral white matter, especially ipsilateral but also contralateral to the side of seizure onset. Volumetric abnormalities in ipsilateral hippocampus and bilateral cerebral white matter are associated with factors related to both the onset and the chronicity of the patients' epilepsy. CONCLUSIONS: These cross-sectional findings support the view that volumetric abnormalities in chronic TLE are associated with a combination of neurodevelopmental and progressive effects, characterized by a prominent disruption in ipsilateral hippocampus and neural connectivity (i.e., white matter volume loss) that extends beyond the temporal lobe, affecting both ipsilateral and contralateral hemispheres.     

Postictal psychosis in temporal lobe epilepsy

PURPOSE: Postictal psychosis is a well-known complication, occurring especially in patients with temporal lobe epilepsy. It usually runs a benign course. The literature on this topic is sparse, and the underlying pathogenic mechanisms are not known. METHODS: We report five patients with temporal lobe epilepsy in whom postictal psychosis developed during the course of video-EEG monitoring; they were studied with hexamethyl-propyleneamine-oxime single-photon emission computed tomography (HMPAO-SPECT) during and after the psychotic event. RESULTS: In comparison to the interictal state, all SPECT scans obtained during postictal psychosis were remarkable for bifrontal and bitemporal hyperperfusion patterns. Some studies also demonstrated unilateral left lateral frontal hyperperfusion. These cortical blood-flow patterns appeared to be distinct from those obtained during complex partial seizures. CONCLUSIONS: Our data suggest that postictal psychoses in patients with temporal lobe epilepsy are associated with hyperactivation of both temporal and frontal lobe structures. This hyperperfusion may reflect ongoing (subcortical) discharges, active inhibitory mechanisms that terminate the seizure, or simply a dysregulation of cerebral blood flow.     

MRI与PET在颞叶癫癎中定位价值的比较

目的 比较ＭＲＩ及ＦＤＧ－ＰＥＴ在颞叶癫癎致癎灶定位中的价值,探讨癫癎外科术前定位的方法以及手术预后的判断。方法 以手术后癫癎控制状况为标准,对３０例颞叶癫癎患者的术前ＭＲＩ和ＦＤＧ－ＰＥＴ的结果进行比较,分析ＭＲＩ及ＰＥＴ各自在癫癎致癎灶定位中的价值。结果ＭＲＩ有良好的脑结构分辨能力,对于症状性癫癎的定位价值高,当ＭＲＩ显示海马硬化时,对致癎灶定位的意义大,术后癫癎发作完全控制的可能性大。发作间期ＰＥＴ对于颞叶癫癎定位的敏感性高于ＭＲＩ,但ＰＥＴ低代谢的范围往往超过致癎灶。与ＰＥＴ的目测方法比较,ＰＥＴ半定量分析并不能提高致癎灶定位的准确性及对手术效果的预测。结论　ＭＲＩ与ＰＥＴ检查结合可以提高致癎灶定位的准确性及对手术效果的预测,减少颅内记录的应用。     

MRI影像改变对颞叶癫痫术后疗效的影响

目的 研究颞叶癫痫(TLE)患者的MRI影像与病理结果 的相关性,分析不同MRI改变对术后疗效的影响.方法 回顾2005年1月至2008年12月在我科手术治疗且有效随访的121例TLE患者的临床资料,统计分析MRI影像改变与病理结果 的关系;根据MRI影像改变将患者分为内侧型TLE、有结构性改变的TLE和隐源性TLE,利用Engel分级将患者分为无发作组和发作组,比较不同类型TLE患者术后疗效的差异.结果 121例患者中MRI结果 阳性101例,病理结果 阳性107例,二者差异无统计学意义,具有良好的相关性.隐源性TLE患者的术后疗效较内侧型TLE和有结构性病变的TLE差,而后二者之间差异无统计学意义.结论 MRI检查对于TLE的确诊及预后判断具有重要意义.     

Efficacy of temporal lobe surgery for epilepsy in patients with negative MRI for mesial temporal lobe sclerosis

Epilepsy surgery is a successful treatment for refractory temporal lobe epilepsy (TLE). Reports suggest fewer seizure-free outcomes for patients with TLE and who have a negative brain MRI (nMRI) for mesial temporal sclerosis. Data were collected prospectively from patients with nMRI who underwent temporal lobe surgery for TLE characterized by unilateral ictal temporal lobe seizure onset based on a scalp video electroencephalogram or invasive subdural electrode recordings. A total of 86 patients were followed for at least 24 months after surgery. Outcome was evaluated using the Engel classification. Seizure control was obtained by 55% (47/86) of patients (Class [CL]-I), 27% (23/86) showed significant improvement (CL-II) and 19% (16/86) were deemed surgical failures. Shorter duration of epilepsy, later onset of seizures, and ictal theta rhythm (5-7 Hz) were the most significant predictors of postoperative seizure control. Although hypometabolism on positron emission tomography scan and significant memory disparity (>2.5/8) were not significant prognosticators independently, cumulatively they were predictors for favorable outcome.     

Postictal mania versus postictal psychosis: differences in clinical features, epileptogenic zone, and brain functional changes during postictal period

PURPOSE: To clarify the differences between postictal mania (PIM) and postictal psychosis (PIP). METHODS: Five patients with PIM were compared to 17 patients with PIP, with respect to clinical, epileptological, electrophysiological, and neuroimaging features. PIM was distinguished from PIP by the symptoms observed in the postictal period based on the ICD-10 criteria. RESULTS: Postictal manic episodes lasted for a longer period than postictal psychotic episodes. Patients with PIM had more recurrent postictal episodes than patients with PIP. The age at onset of epilepsy in patients with PIM was older than that in patients with PIP. PIM was associated with frontal lobe and temporal lobe epilepsies, whereas PIP was associated with temporal lobe epilepsy. The estimated epileptogenic zone was on the language dominant side in PIM, whereas there was no predominant hemispheric laterality in PIP. Electroencephalography (EEG) performed during the early period of postictal manic and psychotic episodes showed decreased frequency of interictal epileptiform discharges in both PIM and PIP. Single-photon emission computed tomography (SPECT) during postictal manic and psychotic episodes showed increased perfusion in the temporal and/or frontal lobes in both PIM and PIP. Three patients with PIM showed increased perfusion during postictal episodes on bilateral or the language nondominant side, which were contralateral to the estimated epileptogenic zone, whereas three patients with PIP showed increased perfusion on the areas, which were ipsilateral to the estimated epileptogenic zone. CONCLUSIONS: PIM has a distinct position among the mental disorders observed in the postictal period.     

视频脑电图结合磁共振扫描对颞叶癫痫术前定位的探讨

目的 探讨视频脑电图及磁共振扫描对颢叶癫痫术前定位的准确性.方法 回顾分析146例颞叶癫痫病例,术前均行长程视频脑电图(V/EEG)监测及磁共振扫描(MRI),发作时V/EEG所示的痫样放电部位与MRI检查所发现的病变同侧时,将此侧颞叶作为癫痫灶颞叶;MRI未见异常,则根据三次以上发作时V/EEG定侧.所有患者经术中皮层脑电图和深部脑电监测后,行前颞叶切除术.结果 术中皮层脑电图及深部脑电监测均发现有痫样放电,与术前V/EEG监测吻合.术后102例(70%)癫痫发作完全消失,显著改善35例(24%),良好6例(4%),无改善3例(2%).结论 V/EEG结合MRI对颞叶癫痫术前能进行准确定位.     

Three-dimensional hippocampal atrophy maps distinguish two common temporal lobe seizure–onset patterns

Purpose:   Current evidence suggests that the mechanisms underlying depth electrode–recorded seizures beginning with hypersynchronous (HYP) onset patterns are functionally distinct from those giving rise to low-voltage fast (LVF) onset seizures. However, both groups have been associated with hippocampal atrophy (HA), indicating a need to clarify the anatomic correlates of each ictal onset type. We used three-dimensional (3D) hippocampal mapping to quantify HA and determine whether each onset group exhibited a unique distribution of atrophy consistent with the functional differences that distinguish the two onset morphologies.
Methods:   Sixteen nonconsecutive patients with medically refractory epilepsy were assigned to HYP or LVF groups according to ictal onset patterns recorded with intracranial depth electrodes. Using preimplant magnetic resonance imaging (MRI), levels of volumetrically defined HA were determined by comparison with matched controls, and the distribution of local atrophy was mapped onto 3D hippocampal surface models.
Results:   HYP and LVF groups exhibited significant and equivalent levels of HA ipsilateral to seizure onset. Patients with LVF onset seizures also showed significant contralateral volume reductions. On ipsilateral contour maps HYP patients exhibited an atrophy pattern consistent with classical hippocampal sclerosis (HS), whereas LVF atrophy was distributed more laterally and diffusely. Contralateral LVF maps also showed regions of subicular atrophy.
Discussion:   The HS-like distribution of atrophy and the restriction of HA to the ipsilateral hippocampus in HYP patients are consistent with focal hippocampal onsets, and suggest a mechanism utilizing intrahippocampal circuitry. In contrast, the bilateral distribution of nonspecific atrophy in the LVF group may reflect mechanisms involving both hippocampal and extrahippocampal networks.     

The expression of interictal, preictal, and postictal facial-wiping behavior in temporal lobe epilepsy: a neuro-ethological analysis and interpretation

By videotape recordings analysis we investigated the frequencies of interictal, preictal, and postictal wiping or rubbing movements targeting the face region (face wiping, FW) in 17 right and 13 left mesial temporal lobe epilepsy (MTLE) patients. Patients' data were compared with FW frequencies obtained in 22 healthy controls listening to a presentation. Results showed that: (1) FW movements were present in both controls and patients; however, the patient groups showed lower interictal and preictal FW rates relative than controls; (2) right and left temporal lobe seizures were followed by a marked increase in the expression of wiping activities directed to the nose as well as to other face regions with respect to the interictal-preictal period; (3) during the first 5min postictal FW was performed preferentially with the hand ipsilateral to the seizure focus; (4) postictal examination of the patient by an observer, especially if of the opposite sex, resulted in a higher incidence of FW acts. After temporal lobe seizures there is an exaggerated expression of movements targeting the face region, and not exclusively directed to the nose. According to an ethological interpretation of the FW behavior as a motor behavior present throughout the phylogenetic scale, from rodents to primates, we suggest the postictal emergence of an innate action pattern modulated by external emotional-cognitive stimuli.     

Temporal lobe epilepsy in children: etiology in a cohort with new-onset seizures

PURPOSE: The aim of this study was to characterize the incidence and etiology of temporal lobe epilepsy (TLE) in a community-based cohort of children with new-onset disease. METHODS: A community-based cohort of 30 children with TLE was studied. The patients had new-onset disease before age 14 years between 1995 and 1999. They underwent clinical, EEG, and magnetic resonance imaging investigations. RESULTS: The patients could be divided in three main groups according to likely etiology, as suggested by Harvey et al. (Neurology 1997;49:960-8). Group 1 consisted of eight (26.7%) children with malformations or long-standing, nonprogressive tumors (developmental TLE). Arachnoid cysts were found in three, dual pathology [cortical dysplasia and hippocampal sclerosis (HS)] in one, and focal cortical dysplasia with glioproliferative changes in one patient. Dysembryoplastic neuroepithelial tumor was responsible for the epilepsy in one, and ganglioglioma, in two children. Group 2 consisted of seven (23.3%) children with a significant antecedent and/or HS. Five children had a significant illness or event before the onset of TLE, including perinatal hypoxic-ischemic encephalopathy in one, encephalitis in one, traumatic brain injury in two, and complex febrile seizures in one. HS was found in the patients with traumatic brain injury and complex febrile seizures in the history in addition to two children without known antecedents. Group 3 comprised 15 (50%) children with no abnormality on neuroimaging and no significant antecedents (cryptogenic TLE). CONCLUSIONS: Etiologic differences between children with new-onset TLE may have prognostic implications: children with TLE and significant antecedents/HS are expected to have the greatest risk of continued seizures and psychological problems.