Nabil J. Azar

Postictal breathing pattern distinguishes epileptic from nonepileptic convulsive seizures.

Purpose: To examine postictal breathing pattern in generalized convulsive nonepileptic seizures (GCNES) and generalized tonic–clonic seizures (GTCS) and evaluate this feature as a discriminating sign.

Considerations in the choice of an antiepileptic drug in the treatment of epilepsy.

The advent of multiple new antiepileptic drugs (AEDs) in the past 15 years has provided new options for clinicians treating patients with epilepsy, but has also created a need for guidelines in AED use. For selection of the most appropriate AED, the neurologist must know the pharmacological properties of the AEDs and has to balance their benefits and potential risks for the individual patient. A key consideration in AED selection is spectrum of efficacy for seizure types and epileptic syndrome. Other factors in AED selection include safety and tolerability, ease of use and titration rate, potential interactions, and efficacy in coexisting nonepileptic conditions. Comorbid conditions may favor or exclude the use of certain AEDs in a particular patient. Special considerations apply in specific epilepsy populations, such as women of childbearing age, children, and the elderly. This article analyzes the various factors involved in choosing an AED.

Inter-rater agreement on identification of electrographic seizures and periodic discharges in ICU EEG recordings

OBJECTIVE This study investigated inter-rater agreement (IRA) among EEG experts for the identification of electrographic seizures and periodic discharges (PDs) in continuous ICU EEG recordings. METHODS Eight board-certified EEG experts independently identified seizures and PDs in thirty 1-h EEG segments which were selected from ICU EEG recordings collected from three medical centers. IRA was compared between seizure and PD identifications, as well as among rater groups that have passed an ICU EEG Certification Test, developed by the Critical Care EEG Monitoring Research Consortium (CCEMRC). RESULTS Both kappa and event-based IRA statistics showed higher mean values in identification of seizures compared to PDs (k=0.58 vs. 0.38; p<0.001). The group of rater pairs who had both passed the ICU EEG Certification Test had a significantly higher mean IRA in comparison to rater pairs in which neither had passed the test. CONCLUSIONS IRA among experts is significantly higher for identification of electrographic seizures compared to PDs. Additional instruction, such as the training module and certification test developed by the CCEMRC, could enhance this IRA. SIGNIFICANCE This study demonstrates more disagreement in the labeling of PDs in comparison to seizures. This may be improved by education about standard EEG nomenclature.

Predictors of a nondiagnostic epilepsy monitoring study and yield of repeat study

OBJECTIVE Failure to record typical events during long-term video/EEG monitoring (LTM) leaves the diagnosis uncertain. The purpose of this study was to analyze predictors of an initial nondiagnostic LTM study and to evaluate the yield of a repeat study. METHODS We reviewed all adult LTM studies performed at Vanderbilt University from January 2004 to June 2008. We identified 150 patients with no typical events on LTM and matched them with consecutive controls with typical events. We compared patient demographics, epilepsy risk factors, history of antiepileptic use/failures, and prior EEG and MRI results. RESULTS Of 2397 LTM studies, 380 (15.8%) failed to record typical events. Absence of epilepsy risk factors and normal outpatient EEG predicted this outcome. A repeat LTM study was successful in 18 of 45 patients (42%). CONCLUSION The prediction of a nondiagnostic LTM can help to reduce the cost of investigating spells of unknown nature.

Tiagabine-induced stupor in patients with psychogenic nonepileptic seizures: Nonconvulsive status epilepticus or encephalopathy?

BACKGROUND Nonconvulsive status epilepticus has been rarely reported with tiagabine (TGB) use. METHODS We report findings from continuous video-EEG monitoring and serial neurological examinations during prolonged episodes of stupor associated with TGB use in three patients who did not have epilepsy. RESULTS All three patients had emergence of new type of events after starting TGB treatment. All three patients had gradual decline in responsiveness to verbal stimuli, intermittent twitching of the upper extremities, and urinary incontinence. The corresponding EEG showed gradual build-up of generalized bisynchronous delta-wave activity with subsequent intermingled sharp transients. Two patients did not respond to IV lorazepam, one of whom also did not respond to IV phenytoin. The EEG slowly normalized in conjunction with associated clinical improvement. Habitual seizures were found to be psychogenic, with no interictal evidence for epilepsy. CONCLUSION Tiagabine-related stupor may represent a form of toxic encephalopathy in some cases rather than nonconvulsive status epilepticus.

Transitional sharp waves at ictal onset--a neocortical ictal pattern.

OBJECTIVE Some seizures are characterized by a transitional sharp wave (TShW) at ictal onset. We evaluated the clinical significance and localizing value of TShW in partial-onset seizures. METHODS We identified and analyzed all scalp ictal recordings with a TShW at ictal onset in the Vanderbilt Epilepsy Monitoring Unit over a period of 12 months. RESULTS A total of 52 ictal discharges in 13 patients started with a TShW. The center of TShW field was concordant with the final localization/lateralization, while that of the subsequent ictal discharge was concordant in only 6 patients. The subsequent rhythmic ictal discharge was non-localizing in 4 patients and misleading in the remaining 3 patients. The final localization was neocortical temporal or frontal in 11 patients, occipito-parietal in one, and undetermined in 1 patient. None of 61 ictal discharges in 15 patients with mesial temporal lobe epilepsy studied in the same time period started with a TShW. CONCLUSION In this patient series, the TShW was a marker of neocortical seizure onset. The TShW field provided more accurate localization or lateralization of the ictal focus than the following rhythmic ictal discharge. SIGNIFICANCE TShW at seizure onset should suggest a neocortical rather than hippocampal seizure onset.

Does adherence to epilepsy quality measures correlate with reduced epilepsy-related adverse hospitalizations? A retrospective experience.

In 2011, the American Academy of Neurology (AAN) established eight epilepsy quality measures (EQMs) for chronic epilepsy treatment to address deficits in quality of care. This study assesses the relationship between adherence to these EQMs and epilepsy‐related adverse hospitalizations (ERAHs). A retrospective chart review of 475 new epilepsy clinic patients with an ICD‐9 code 345.1‐9 between 2010 and 2012 was conducted. Patient demographics, adherence to AAN guidelines, and annual number of ERAHs were assessed. Fishers exact test was used to assess the relationship between adherence to guidelines (as well as socioeconomic variables) and the presence of one or more ERAH per year. Of the eight measures, only documentation of seizure frequency, but not seizure type, correlated with ERAH (relative risk [RR] 0.343, 95% confidence interval [CI] 0.176–0.673, p = 0.010). Among patients in the intellectually disabled population (n = 70), only review/request of neuroimaging correlated with ERAH (RR 0.128, 95% CI 0.016–1.009, p = 0.004). ERAHs were more likely in African American patients (RR 2.451, 95% CI 1.377–4.348, p = 0.008), Hispanic/Latino patients (RR 4.016, 95% CI 1.721–9.346, p = 0.016), Medicaid patients (RR 2.217, 95% CI 1.258–3.712, p = 0.009), and uninsured patients (RR 2.667, 95% CI 1.332–5.348, p = 0.013). In this retrospective series, adherence to the eight AAN quality measures did not strongly correlate with annual ERAH.

Temporal pattern of oxcarbazepine and phenytoin withdrawal seizures during epilepsy monitoring

PURPOSE To compare the temporal pattern of seizures after acute withdrawal of oxcarbazepine (OXC) and phenytoin (PHT) in the epilepsy monitoring unit (EMU). METHODS We identified all epilepsy patients admitted to our EMU on OXC or PHT monotherapy, over a period of 5 years. The OXC taper usually occurred over 2 days while PHT was abruptly discontinued on admission day. For each patient, we recorded the number and type of seizures for each EMU day. We used Poisson regression models to estimate daily seizure frequency separately for complex partial seizures (CPSs) and generalized tonic-clonic seizures (GTCSs). RESULTS Forty patients were admitted on OXC and 32 on PHT monotherapy. The temporal distribution of seizures varied between the two groups. The first GTCS was more likely to occur in the first 2 days of monitoring for the OXC group (p<0.046). There was a higher frequency of GTCS on day 2 of admission in the OXC group (p=0.011). The groups did not differ in the pattern of CPS. CONCLUSIONS OXC is disproportionately associated with increased GTCS in the first 2 days after acute withdrawal. The early peak of GTCS favors a rebound phenomenon in addition to loss of therapeutic effect.

Communicating the diagnosis of psychogenic nonepileptic seizures: The patient perspective

Psychogenic nonepileptic seizures (PNES) are a common cause of refractory seizures. Video-electroencephalographic (EEG) monitoring has allowed PNES to be effectively distinguished from epileptic seizures. Once the diagnosis of PNES is established, neurologists face the challenge of explaining it to patients. Patients may not always receive the diagnosis well. The aim of this study is to evaluate how effectively patients receive and perceive the diagnosis of PNES. This prospective study was conducted in an eight-bed epilepsy monitoring unit (EMU). Adult patients with newly confirmed PNES were included. After receiving written consent, a self-administered questionnaire was given to patients after the attending physician had communicated the diagnosis of PNES. A total of 75 patients were recruited. All patients had their typical seizures recorded on video-EEG (range 1-12, mean 2.18). Seventy patients were satisfied with the diagnosis of PNES. Nine patients did not agree that PNES has a psychological cause. Nineteen patients thought that the EMU doctors had no clue as to the cause of their seizures and 20 thought that there was no hope for a cure of their seizures. A significant number of patients with PNES feel that there is no hope for cure of their seizures. Thorough education about PNES, properly preparing patients before discussing the diagnosis of PNES, and preferably earlier diagnosis may prevent this miscommunication and result in better outcomes. A comprehensive approach including psychological counseling and psychiatric input, evaluation and treatment, in order to bring the illness from the subconscious to the conscious level, and effective follow-up may be helpful.

Acute pancreatitis and elevated liver transaminases after rapid titration of oral levetiracetam

We report a 25-year-old woman with new onset convulsive episodes. The patient initially failed to respond to phenytoin and was switched to levetiracetam (LEV) which was rapidly titrated to 3000 mg daily over 1 week. At initiation of LEV therapy, she developed mild nausea and decrease in appetite. This was rapidly followed by severe digestive symptoms consistent with acute pancreatitis. She was also found to have elevated liver transaminases. An extensive work-up failed to reveal an organic cause for her symptoms, suggesting a direct relationship to LEV. Clinical symptoms and laboratory abnormalities normalized after LEV discontinuation, along with supportive therapy.