Automated normalized FLAIR imaging in MRI-negative patients with refractory focal epilepsy

Background:   Patients with focal epilepsy that is refractory to medical treatment are often considered candidates for resective surgery. Magnetic resonance imaging (MRI) has a very important role in the presurgical work-up of these patients, but is unremarkable in about one-third of cases. These patients are often deferred from surgery or have a less positive outcome if surgery is eventually undertaken. The aim of this study was to evaluate our recently described voxel-based technique using routine T2-FLAIR (fluid-attenuated inversion-recovery) scans in MRI-negative patients and to compare the results with video-EEG (electroencephalography) telemetry (VT) findings.
Methods:   We identified 70 epilepsy patients with refractory focal seizures who underwent VT and had a normal routine MRI. T2-FLAIR scans were bias-corrected, and intensity and spatially normalized (nFSI) using Statistical Parametric Mapping 5 (SPM5) as previously described. Individual scans were then compared against a set of 25 normal controls using a voxel-based method.
Results:   SPM5 identified 10 patients with suprathreshold clusters (14.3%). In 50% of these there was concordance between the lobe of the most significant cluster and the presumed lobe of seizure onset, as defined by VT. All cases were concordant with respect to lateralization of the putative focus.
Conclusion:   Using nFSI we identified focal structural cerebral abnormalities in 11.4% of patients with refractory focal seizures, and normal conventional MRI, that were fully or partially concordant with scalp VT. This voxel-based analysis of FLAIR scans, which are widely available, could provide a useful tool in the presurgical evaluation of epilepsy patients. Ongoing work is to compare these imaging findings with the results of intracranial EEG and histology of surgical resections.     

From the analogic to the digital era: technical EEG progress for presurgical investigations of refractory partial epilepsies

Over the past two decades, exploration of epileptic patients has benefited from technological advances in electroencephalography. Computerized equipment can simultaneously retrieve cerebral electric activity and signs of the patient's ictal activity. The computer era has improved reliability, storage and analysis of the recorded data and provides easier communication tools for multidisciplinary staff and patient case studies. Therefore, an increasing number of patients could benefit from presurgical investigations and surgical treatment.     

儿童肌阵挛癫痫临床和录像脑电图分析

目的：探讨儿童肌阵挛癫痫患儿的临床、脑电图（EEG）和治疗特点。方法：对35例肌阵挛癫痫患儿的临床表现、录像脑电图（V-EEG）及抗癫痫药物的治疗效果进行回顾性分析。结果：35例均有肌阵挛发作,以肌阵挛为唯一的发作形式9例,其它26例合并强直阵挛发作、强直发作、部分性发作等发作类型。30例患儿EEG可见全导棘慢波或多棘慢波暴发,5例患儿为局灶性异常。28例明确为癫痫综合征,以青少年肌阵挛性癫痫和Lennox-Gastaut综合征最常见。多数患儿对丙戊酸治疗有效。结论：肌阵挛癫痫以肌阵挛发作为主要表现,正确的诊断依靠详细的询问肌阵挛发作的病史和V-EEG检查结果,治疗应首选丙戊酸。     

Posttraumatic epilepsy: The endophenotypes of a human model of epileptogenesis

Posttraumatic epilepsy is a common complication of traumatic brain injury (TBI), occurring in up to 15–20% of patients with severe brain trauma. Trauma accounts for approximately 5% of chronic epilepsy in the community. Because it is a common condition, and because of the relatively short latency period between injury and onset of chronic seizures, posttraumatic epilepsy represents a good model to test antiepileptogenic therapies. However, several well-conducted clinical trials have failed to demonstrate antiepileptogenic efficacy for several common anticonvulsants. Posttraumatic epilepsy can arise through a number of mechanisms, which often coexist within a single patient. Penetrating brain injury produces a cicatrix in the cortex and is associated with a risk of posttraumatic epilepsy of approximately 50%, whereas nonpenetrating head injury may produce focal contusions and intracranial hemorrhages, and is associated with a risk of posttraumatic epilepsy of up to 30%. Furthermore, closed head injury often produces diffuse concussive injury, with shearing of axons and selective damage to vulnerable brain regions, such as the hippocampus. The clinical, neurophysiologic, imaging, and neuropathologic features or epileptogenicity differ between these alternate mechanisms. It is likely that better understanding of the subtypes of epilepsy resulting from brain trauma will be required to successfully identify antiepileptogenic therapies.     

Neuropsychological study during video-EEG recording of successive partial seizures of right temporo-central origin

A 15-year-old, right-handed boy underwent video-EEG study as a first step in presurgical evaluation for a severe drug-resistant right temporo-central epilepsy. He was monitored while performing neuropsychological tests over a 67-minute period during which 23 brief seizures were recorded. Despite his right-handedness, both inter-ictal and ictal verbal performances were impaired. Analysis of the relationships between the characteristics of the EEG and the neuropsychological results revealed that a worsening in cognitive performances correlated with an increase in interictal abnormalities, particularly when subclinical paroxysms were present; that the cognitive tasks executed peri-ictally were correctly performed in almost 50% of the cases; and that the error rate was higher when a task was presented during or immediately after a seizure rather than before its onset. A Wada test, performed on the basis of the cognitive results, demonstrated right hemisphere dominance for language. Our observations underline the importance of neuropsychological testing in presurgical procedures, and suggest that it should be performed peri-ictally whenever possible.

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Sommario Viene riportato il caso di un destrimane di 15 anni affetto da una grave epilessia farmaco-resistente centro-temporale destra e sottoposto a video-EEG come primo passo della valutazione prechirurgica. Durante il monitoraggio furono registrate 23 brevi crisi nell'arco di 67 minuti mentre eseguiva parte dell'indagine neuropsicologica. In intercritico e soprattutto in critico la prestazione del soggetto alle prove verbali è risultata deficitaria. Analizzando la relazione tra dati EEG e neuropsicologici abbiamo rilevato: — un peggioramento della prestazione cognitiva correlato ad un aumento delle anomalie intercritiche in particolare in presenza dei parossismi infraclinici; — che quando gli item erano eseguiti in percritico erano corretti circa il 50% delle volte; — un'alta incidenza di errori quando il compito era presentato durante o immediatamente dopo una crisi piuttosto che prima del suo inizio. Sulla base dei dati neuropsicologici è stato eseguito il test di Wada che ha dimostrato una dominanza emisferica destra per il linguaggio. Dalla nostra osservazione emergono l'importanza della valutazione neuropsicologica nell'approccio prechirurgico dell'epilessia e il suggerimento di utilizzarla in percritico quando possibile.

     

视频脑电图监测对儿童非癫痫性发作的诊断价值

目的 评价视频脑电图(VEEG)在诊断儿童非癫痫性发作(NES)中的作用。方法 对105例经1∽4hVEEG动态监测后诊断为NES患儿的临床资料进行回顾性分析，探讨影响诊断的因素。结果 105例NES中，心理性NES14例(13％)，躯体性NES91例(87％)。43例此前接受过普遍EEG检查的患儿中11例(26％)曾被误诊。结论 VEEG是明确小儿非癫痫性发作的种类、鉴别非癫痫性与癫痫发作的可靠的方法，发作间隙期EEG异常是导致NES误诊的主要因素。     

De Novo Psychogenic Nonepileptic Seizures After Epilepsy Surgery

Summary: Purpose: The occurrence of de novo nonepileptic seizures (NES) after epilepsy surgery have been reported only twice in the literature (one article and one abstract).
Methods: We report three patients whose de novo NES were documented by video-EEG telemetry after epilepsy surgery. These patients were drawn from a sample of 166 consecutive patients who underwent epilepsy surgery at our center between 1989 and 1996.
Results: Two patients became seizure free after surgery, and one had significant improvement of her seizures. The interval between the date of surgery and the development of the symptoms was variable (8, 10, and 47 months, respectively). The clinical phenomena of NES differed from those of the epileptic seizures preceding surgery. Their diagnosis had not been suspected in two patients before the diagnostic video-EEG monitoring study. After the diagnosis of NES, spells stopped in two patients and recurred rarely in one.
Conclusions: We conclude that de novo NES appears to occur rarely after epilepsy surgery. Given that the possibility of NES was suspected in only one patient, its incidence after surgery may be higher than so far reported. Physicians should therefore consider NES in the differential diagnosis of recurrent seizures after a seizure-free period after epilepsy surgery.     

Evaluating the utility of inpatient video-EEG monitoring

PURPOSE: Inpatient video-EEG monitoring (VEM) is widely used for the diagnosis, seizure classification, and presurgical evaluation of patients with seizure disorders. It is resource intensive and relatively expensive, so its utility continues to be debated. Few studies have specifically evaluated the utility of inpatient VEM in altering diagnosis or management of patients with seizure disorders. We sought to assess the proportion of patients for whom the preadmission diagnosis and management were altered after inpatient VEM of patients admitted for diagnostic and presurgical evaluation of seizure disorders. METHODS: Data from a consecutive cohort of patients admitted over a 3-year period to an inpatient VEM unit in a tertiary referral hospital were retrospectively analyzed. The preadmission diagnosis and management by the referring neurologist was compared with the diagnosis and management after the VEM. RESULTS: Of 131 patients, 91 (70%) were admitted for diagnostic evaluation and 39 (30%) for a presurgical workup. Mean evaluative period was 5.6 days. Mean number of seizures recorded was 2.9. No seizures were recorded in 31% of patients. Interictal EEG showed epileptiform changes in 56 (43%). In 76 (58%), the diagnosis was altered as a result of the VEM, with the greatest change being an increase in the nonepileptic diagnosis group (7% to 31%) and the generalized diagnosis group (5% to 11%). Management was changed after the VEM in 95 (73%). CONCLUSIONS: The results of this study demonstrate that inpatient VEM has a high yield in changing diagnosis and management. Future long-term cost-benefit studies of the management changes resulting from VEM evaluation will aid in further reinforcing its role.     

Seizure semiology in the elderly: a video analysis

PURPOSE: To describe the seizure semiology of patients older than 60 years and to compare it with that of a control group of younger adults matched according to the epilepsy diagnosis. METHODS: Available videotapes of all patients aged 60 years and older who underwent long-term video-EEG evaluation at the Cleveland Clinic Foundation (CCF) between January 1994 and March 2002 were analyzed by two observers blinded to the clinical data. A younger adult control group was matched according to the epilepsy diagnosis, and their seizures also were analyzed. RESULTS: Fifty-four (3.3%) of the 1,633 patients were 60 years or older at the time of admission. For 21 of them, at least one epileptic seizure was recorded. Nineteen patients had focal epilepsy (nine temporal lobe, two frontal lobe, two parietal lobe, eight nonlocalized), and two patients had generalized epilepsy. Seventy-three seizures of the elderly patients and 85 seizures of the 21 control patients were analyzed. In nine elderly patients and 14 control patients, at least one of their seizures started with an aura. Eleven elderly patients and 19 control patients lost responsiveness during their seizures. Approximately two thirds of the patients in both groups had automatisms during the seizures. Both focal and generalized motor seizures (e.g., clonic or tonic seizures) were seen less frequently in the elderly. CONCLUSIONS: Only a small percentage of the patients admitted to a tertiary epilepsy referral center for long-term video-EEG monitoring are older than 60 years. All seizure types observed in the elderly also were seen in the younger control group, and vice versa. Simple motor seizures were seen less frequently in the elderly.     

Antiepileptic drug withdrawal in patients with temporal lobe epilepsy undergoing presurgical video-EEG monitoring

PURPOSE: To investigate antiepileptic drug (AED) withdrawal during video-EEG monitoring in adult patients with temporal lobe epilepsy (TLE). METHODS: Between 1995 and 1997, 102 consecutive patients with refractory TLE were admitted to the epilepsy monitoring unit for presurgical evaluation. Patients were monitored with ongoing AEDs being rapidly decreased and discontinued in 4-6 days. The monitoring was continued until sufficient numbers of seizures were recorded. Serum AED levels were checked at admission and after the first complex partial seizure (CPS). RESULTS: In all, 89 patients had 429 CPSs (mean, 4.8 per patient), including 156 (36.4%) secondarily generalized. A mean of 153.8 h (16-451 h) was required for completing the monitoring in each patient. Forty-three (48.3%) patients experienced seizure clusters, and eight (9.0%) had generalized seizures that had never occurred or had been absent for years. However, none evolved to status epilepticus. Carbamazepine was the most commonly used AED in 71.9% of patients, followed by valproate and phenytoin. When the first CPS occurred, mean 77.2 h since the beginning of the monitoring, serum levels of these three AEDs were mostly subtherapeutic rather than minimal. CONCLUSIONS: Acute AED withdrawal effectively provoked seizures in TLE patients undergoing presurgical video-EEG monitoring. However, nearly 50% of patients had seizure clusters or secondarily generalized seizures. Serum AED levels were mostly subtherapeutic when the first CPS occurred.