EEG interpretation reliability and interpreter confidence: a large single-center study.

The intrarater and interrater reliability (I&IR) of EEG interpretation has significant implications for the value of EEG as a diagnostic tool. We measured both the intrarater reliability and the interrater reliability of EEG interpretation based on the interpretation of complete EEGs into standard diagnostic categories and rater confidence in their interpretations and investigated sources of variance in EEG interpretations. During two distinct time intervals, six board-certified clinical neurophysiologists classified 300 EEGs into one or more of seven diagnostic categories and assigned a subjective confidence to their interpretations. Each EEG was read by three readers. Each reader interpreted 150 unique studies, and 50 studies were re-interpreted to generate intrarater data. A generalizability study assessed the contribution of subjects, readers, and the interaction between subjects and readers to interpretation variance. Five of the six readers had a median confidence of ≥99%, and the upper quartile of confidence values was 100% for all six readers. Intrarater Cohen's kappa (κc) ranged from 0.33 to 0.73 with an aggregated value of 0.59. Cohen's kappa ranged from 0.29 to 0.62 for the 15 reader pairs, with an aggregated Fleiss kappa of 0.44 for interrater agreement. Cohen's kappa was not significantly different across rater pairs (chi-square=17.3, df=14, p=0.24). Variance due to subjects (i.e., EEGs) was 65.3%, due to readers was 3.9%, and due to the interaction between readers and subjects was 30.8%. Experienced epileptologists have very high confidence in their EEG interpretations and low to moderate I&IR, a common paradox in clinical medicine. A necessary, but insufficient, condition to improve EEG interpretation accuracy is to increase intrarater and interrater reliability. This goal could be accomplished, for instance, with an automated online application integrated into a continuing medical education module that measures and reports EEG I&IR to individual users.

Acute postictal confusion and violence: Two cases with unfortunate outcomes.

Patients with temporal lobe epilepsy (TLE) often have a brief postictal state characterized by confusion and disorientation. Less common postictal behaviors include wandering and violence - both reactive and spontaneous. We describe two male patients with left TLE and unusual postictal states that led to unfortunate outcomes. The first patient's postictal state included an intense urge to peregrinate, as well as reactive violence. When a frightened houseguest prevented the patient from exiting his bedroom during a postictal state, the patient climbed out the window and fell to his death. The second patient's postictal state included menacing posturing, loud exclamation of guttural sounds or profanities, clapping or smacking his hands together, and punching nearby objects. During a postictal state at home, he grabbed a bat and destroyed furnishings. After he had two seizures at work followed by his typical postictal state, he was dismissed because of his perceived threat to coworkers.

A patient with distinct dissociative and hallucinatory fugues.

A 62-year-old man presented with a history suggesting both dissociative fugue and a distinct fugue-like hallucination. The dissociative fugues included unplanned travel, loss of personal identity, inability to recall his past and amnesia for the fugue interval. The subjective fugues consisted of a stereotyped hallucination wherein he would travel to a social gathering place, meet his 'imaginary friends' and engage with them in conversation. He experienced the subjective fugues as if they were real, recognised them as hallucinations when he was normally conscious, and remembered them in great detail. A hallucinatory fugue episode occurred during video-EEG monitoring. The patient engaged in semipurposeful behaviour for which he had no memory, and the EEG demonstrated waking rhythms. Epilepsy, sleep disorder, factitious disorder and malingering were excluded from the differential diagnosis, leaving a patient with both dissociative and hallucinatory fugues, likely made possible by remote traumatic injury to limbic, arousal and motor circuits.

Sutton's law in epilepsy: because that is where the lesion is.

Successful epilepsy surgery requires unambiguous identification of the epileptogenic zone. This determination may be a challenge when the pre-surgical evaluation yields conflicting data. We evaluated an adult patient with a right insular mass, but a seizure semiology, interictal EEG, and ictal EEG, suggesting left temporal lobe epilepsy. Resection of the mass, a ganglioglioma, resulted in seizure freedom and disappearance of interictal left temporal lobe epileptiform discharges. This case illustrates the principle that in localization-related epilepsy, the money is usually in the mass.

Marijuana: an effective antiepileptic treatment in partial epilepsy? A case report and review of the literature.

Although more data are needed, animal studies and clinical experience suggest that marijuana or its active constituents may have a place in the treatment of partial epilepsy. Here we present the case of a 45-year-old man with cerebral palsy and epilepsy who showed marked improvement with the use of marijuana. This case supports other anecdotal data suggesting that marijuana use may be a beneficial adjunctive treatment in some patients with epilepsy. Although challenging because of current federal regulations, further studies are needed to examine the role of marijuana in the treatment of this disorder.

Clinical characteristics of psychogenic nonepileptic seizure status in the long-term monitoring unit.

Patients with psychogenic nonepileptic seizures (PNES) mimicking status epilepticus (PNES-status) are at risk of iatrogenic complications. Our aim was to assess whether the population of patients with PNES who develop PNES-status are distinguishable. Retrospectively, we identified patients with PNES-status and compared them with patients with PNES without status and with patients with electroclinical status epilepticus (SE). Of 49 patients with PNES, 9 had PNES-status (18.2%) and 40 had PNES only. Compared with patients with PNES, subjects with PNES-status had taken fewer than three antiepileptic medications (P=0.016), had more than one event per week (P=0.026), were more likely to be admitted emergently to the monitoring unit (P=0.007), had shorter long-term monitoring (LTM) stays (P=0.003), and tended to be diagnosed sooner after initial presentation (P=0.058). Use of fewer than three antiepileptic drugs and emergent admission were independent predictors of PNES-status classification on logistic regression. Of 154 patients with epilepsy, 8 had SE during LTM (5.2%), significantly fewer than the proportion with PNES-status relative to PNES (P=0.008); the only clinical variable distinguishing these two groups was a baseline lower seizure frequency among the patients with epileptic seizures (P=0.045). Our results suggest that patients with PNES-status have features that differentiate them from patients with PNES without status and, to a lesser extent, from patients with epileptic seizures.

Practical strategies for switching to newer antiepileptic drugs.

Traditional antiepileptic drugs (AEDs) are associated with drug interactions and side effects that limit their safety and tolerability. Side effects of traditional AEDs are especially problematic for children and adolescents, women of childbearing age, and the elderly. Many patients with epilepsy may benefit from switching from a traditional AED to a newer agent because the newer agents are generally better tolerated and are less likely to cause drug interactions. Clinical studies have demonstrated improved therapeutic efficiency with better tolerability in patients switching from a traditional AED to lamotrigine, oxcarbazepine, or topiramate monotherapy or combination therapy.