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.

Narcolepsy: clinical approach to etiology, diagnosis, and treatment.

Narcolepsy is a neurologic disorder characterized by excessive daytime sleepiness and manifestations of disrupted rapid eye movement sleep stage. The pathologic hallmark is loss of hypocretin neurons in the hypothalamus likely triggered by environmental factors in a susceptible individual. Patients with narcolepsy, in addition to excessive daytime sleepiness, can present with cataplexy, sleep paralysis, sleep fragmentation, and hypnagogic/hypnopompic hallucinations. Approximately 60% to 90% of patients with narcolepsy have cataplexy, characterized by sudden loss of muscle tone. Only 15% of patients manifest all of these symptoms together. Narcolepsy can be misdiagnosed as a psychiatric disorder or even epilepsy. An appropriate clinical history, polysomnogram, Multiple Sleep Latency Test, and, at times, cerebrospinal fluid hypocretin levels are necessary for diagnosis. The treatment of narcolepsy is aimed toward the different symptoms that the patient manifests. Excessive daytime sleepiness is treated with amphetamine-like or non-amphetamine-like stimulants. Cataplexy is treated with sodium oxybate, tricyclic antidepressants, or selective serotonin and norepinephrine reuptake inhibitors. Sleep paralysis, hallucinations, and fragmented sleep may be treated with benzodiazepine hypnotics or sodium oxybate. Patients with narcolepsy should avoid sleep deprivation, sleep at regular hours, and, if possible, schedule routine napping.

Ocular melanoma metastatic to skin: the value of HMB-45 staining.

BACKGROUND: Cutaneous metastatic disease is an important finding that may represent the first sign of systemic cancer, or, if already known, that may change tumor staging and thus dramatically altered therapeutic plans. Although cutaneous metastases are relatively frequent in patients with cutaneous melanoma, they are less so from ocular melanoma. OBJECTIVE: To demonstrate the value of HMB-45, staining in the detection of ocular melanoma metastatic to skin. METHODS: The immunohistochemical stain HMB-45 a monoclonal antibody directed against intact human melanoma cells, was employed on a skin biopsy specimen from a cutaneous tumor. RESULTS: HMB-45 staining was positive in the atypical hyperchromatic cells of the deep dermis. CONCLUSION: HMB-45 may be of value in the detection of ocular melanoma metastatic to skin. Cutaneous metastatic disease is a somewhat common and extremely important diagnosis. Although cutaneous metastases from cutaneous melanoma are relatively frequent, those from ocular melanomas are less so. Use of histochemical staining, especially the HMB-45 stain, allows confirmation of the diagnosis.