Videotaping epileptic attacks during stereoelectroencephalography

Violence and the epilepsy defense

The essence of the epilepsy defense is the argument that a crime was committed as a result of the perpetrator having epilepsy, and thus that he or she should not be held responsible for a violent crime. Neurologists are frequently asked to pass judgment regarding whether an alleged act may have been the result of an epileptic condition; therefore, neurologists should be informed as to what criteria should be used to decide if a given act was, or could have been, the result of an epileptic seizure. This article discusses three cases where epilepsy is used as the defense argument. In addition, this article reviews types of epileptic seizures, syncopal events, and pseudoseizures.

Intensive neurodiagnostic monitoring in psychiatry

A series of technological advances have made it possible to closely monitor electrophysiological and behavioural manifestations of episodic clinical events over prolonged periods of time, with the ability to review the records at leisure or to submit them to computer analysis. The more promising techniques are time-locked video/EEG monitoring, cable telemetry, radiotelemetry, ambulatory cassette recording, intensive plasma anti-epileptic drug monitoring and continuous neuropsychological monitoring. The greatest promise of these techniques is for the diagnosis, research and management of epilepsy. For psychiatry, they offer additional help in the differential diagnosis of non-epileptic events from epilepsy, the most important of which are psychogenic seizures and episodes of aggression. This paper discusses the potential role of these techniques in the assessment of non-epileptic events and transient cognitive impairment in clinical psychiatry.

Functional and morphological abnormalities in temporal lobe epilepsy: a comparison of interictal and ictal EEG, CT, MRI, SPECT and PET

Ten patients suffering from drug-resistant complex partial seizures, with EEG abnormalities in the temporal region, were studied by means of non-invasive electrophysiological techniques (video-monitored, 16-channel, prolonged surface and sphenoidal EEG) as well as by imaging techniques (CT, MRI, SPECT and PET). Analysis of interictal and ictal EEG indicated the localization of epileptic activity in one side in eight cases. CT demonstrated focal abnormalities in three, SPECT in five unequivocally (in another four questionably, with the same lateralization as indicated by PET), MRI in eight, and PET in all cases. While only EEG provided specific diagnostic information, the focus definition was consistently good on PET images, poor on CT scans, and generally good but less consistent on MRI.

Surface and deep EEG correlates of surgical outcome in temporal lobe epilepsy

Interictal and ictal EEG characteristics derived from limited surface montages and medial temporal lobe sites were compared with long-term seizure relief following anterior temporal lobectomy in 52 epileptics. Patients were classified into one of four surgical outcome groups, ranging from seizure free to no clinical improvement. For each patient, interictal records were analyzed according to deep and surface spike characteristics and background activity. Ictal records were analyzed according to the proportion of episodes initiated in a unilateral or bilaterally synchronous fashion, the proportion of surface or deep onsets, the variability of onset location, and the morphology of seizures onsets. Interictal EEG variables that correlates with surgical outcome included: (a) various types of bilaterally synchronous surface/deep spikes; (b) diffuse background slowing; (c) sharp waves; and (d) the presence of multiple independent deep spike patterns in the lobe chosen for resection. Relevant ictal EEG variables included: (a) episodes initiated in a bilaterally synchronous fashion; (b) variability in seizure onset location; (c) the proportion of precisely focal onsets from deep sites; (d) the proportion of surface onsets; and (e) the proportion of onsets from the side chosen for resection. Multivariate analysis of these data with linear, stepwise, discriminate analysis and adaptive, nonlinear, distribution-free pattern recognition demonstrated that: (a) both interictal and ictal EEG characteristics can independently predict surgical outcome at levels significantly better than chance; (b) ictal and interictal EEG data contain nonredundant information for making such predictions; and (c) nonlinear pattern recognition techniques are capable of deriving the most accurate rules for predicting the effects of surgery.

Depth electroencephalography in selection of refractory epilepsy for surgery

Depth electroencephalography (EEG) is sometimes used to evaluate medically refractory epileptic patients for surgical treatment. Surgical excision of well-defined epileptogenic foci has been shown repeatedly to cause a substantial reduction of seizure frequency in 60 to 80% of these patients; however, because surgical success is no better at centers that employ depth EEG in patient evaluation, the procedure remains controversial. Review of the available literature shows that depth EEG results reported to date, when compared to scalp EEG results in 178 patients, could have enabled selection of 36% more patients for surgery by defining otherwise unidentifiable single epileptogenic foci. Furthermore, depth EEG could have prevented surgery in another 18% by demonstrating different or additional epileptogenic foci in patients otherwise thought to have a single discharging focus amenable to resection. Thus depth EEG had the potential to alter the surgical decision in more than 50% of patients reported. Centers that employ depth EEG may evaluate a different population of patients, which could account for their lack of increased surgical success.

Epilepsy in adults

The past decade has seen advances in the management of patients with epilepsy. The development of practical long-term electroencephalographic techniques, with or without simultaneous video recording, has increased the accuracy of diagnosis of seizure types. The technique also provides clinicians and investigators with a method for establishing the clinical efficacy of antiepileptic drugs and determining their therapeutic serum concentrations. Computerized tomography has enhanced the identification of structural brain lesions. Most of the reported CT abnormalities consist of diffuse and focal atrophies, mild ventricular dilatations, and porencephalies. CT has detected tumors in 8 to 10% of the patients regardless of age or type of seizure involved. New concepts of antiepileptic drug therapy have developed from the recognition of pharmacological properties peculiar to each agent. Determination of serum antiepileptic drug levels has to be utilized to reduce the problem of pharmacokinetic variability from one patient to another and in the same patient at different times, so that dosage can be individualized to achieve maximum therapeutic effects with least toxicity. Review of the literature on pregnancy in epileptic women shows that a third to half experienced more seizures during gestation. Reduced serum levels of most antiepileptic drugs have recently been observed during gestation. Infants of epileptic women taking antiepileptic drugs have a two to three times greater risk for congenital anomalies than infants of nonepileptic women. However, with the exception of oxazolidinediones, evidence to date has not proved the teratogenicity of antiepileptic drugs. The role of genetic factors and the effect of seizures during pregnancy have not been determined. Modest progress has been made in epilepsy rehabilitation, but serious problems still remain. The unemployment rate of persons with epilepsy is twice the national average. Half of those who are successfully employed did not disclose their disorder at the time of employment. Several prognostic indicators have been reported, but the validity of many of these indicators is questionable. For example, does shorter life expectancy apply to all subgroups, or does it vary according to seizure type and cause? The life expectancy, treatment response, and probability of remission in epileptic persons must be reevaluated after consistent applications of current methods of epilepsy management.

Evaluation of childhood pseudoseizures using EEG telemetry and video tape monitoring

Pseudoseizures, clinical events that superficially resemble epileptic attacks but which are not associated with central nervous system paroxysmal activity, are often difficult to differentiate from epileptic seizures. To evaluate the frequency and clinical manifestations of pseudoseizures in children with intractable seizures, children admitted to a Comprehensive Epilepsy Unit received prolonged simultaneous EEG telemetry and video recording. Pseudoseizures occurred in 11 of 53 pediatric patients admitted during the study period. Eight of the 11 patients with pseudoseizures also had documented epileptic seizures. Clinical characteristics of pseudoseizures and epileptic seizures documented by TEEG-VR were compared. Degree and duration of the postictal state, incontinence, combativeness, relationship to stress, and response to anticonvulsant medication were useful differentiating criteria. Pseudoseizures are not unusual in pediatric patients, often occur concurrently with epileptic seizures, and may be difficult to diagnose. However, careful clinical observation may offer clues in differentiating pseudoseizures from epileptic seizures.