Amir Arain

Resting functional MRI with temporal clustering analysis for localization of epileptic activity without EEG.

We report on the methods and initial findings of a novel noninvasive technique, resting functional magnetic resonance imaging (fMRI) with temporal clustering analysis (TCA), for localizing interictal epileptic activity. Nine subjects were studied including six temporal lobe epilepsy (TLE) patients with confirmed localization indicated by successful seizure control after resection. The remaining three subjects had standard presurgical evaluations with inconsistent results or suspected extratemporal lobe foci. Peaks of activity, presumably epileptic, were detected in all nine subjects, using the resting functional MRI with temporal clustering analysis. In all six patients who underwent resective surgery, the fMRI with temporal clustering analysis accurately determined the epileptogenic hippocampal hemisphere (P = 0.005). In the three subjects without confirmed localization, the technique determined regions of activity consistent with those determined by the presurgical assessments. Though more studies are required to validate this technique, the results demonstrate the potential of the resting fMRI with temporal clustering technique to detect and localize epileptic activity without the need for simultaneous electroencephalography (EEG). The greatest potential benefit of this technique will be in the evaluation of patients with suspected extratemporal lobe epilepsy and patients whose standard assessments are discordant.

Standardized database development for EEG epileptiform transient detection: EEGnet scoring system and machine learning analysis

The routine scalp electroencephalogram (rsEEG) is the most common clinical neurophysiology procedure. The most important role of rsEEG is to detect evidence of epilepsy, in the form of epileptiform transients (ETs), also known as spike or sharp wave discharges. Due to the wide variety of morphologies of ETs and their similarity to artifacts and waves that are part of the normal background activity, the task of ET detection is difficult and mistakes are frequently made. The development of reliable computerized detection of ETs in the EEG could assist physicians in interpreting rsEEGs. We report progress in developing a standardized database for testing and training ET detection algorithms. We describe a new version of our EEGnet software system for collecting expert opinion on EEG datasets, a completely web-browser based system. We report results of EEG scoring from a group of 11 board-certified academic clinical neurophysiologists who annotated 30-s excepts from rsEEG recordings from 100 different patients. The scorers had moderate inter-scorer reliability and low to moderate intra-scorer reliability. In order to measure the optimal size of this standardized rsEEG database, we used machine learning models to classify paroxysmal EEG activity in our database into ET and non-ET classes. Based on our results, it appears that our database will need to be larger than its current size. Also, our non-parametric classifier, an artificial neural network, performed better than our parametric Bayesian classifier. Of our feature sets, the wavelet feature set proved most useful for classification.

Predictors of early seizure remission after diagnosis of psychogenic nonepileptic seizures

Psychogenic nonepileptic seizures (PNES) are very common, but limited outcome data are available. The purpose of this study was to evaluate the predictors of seizure remission after the diagnosis of PNES is made with video/EEG monitoring in an epilepsy referral center. The subjects for this analysis were 48 consecutive patients who returned for follow-up after diagnosis of PNES. We evaluated demographic, psychosocial, educational, and clinical features as predictors of outcome, using logistic regression analysis outcome. At follow-up, only 35% of patients had achieved seizure remission, and only 50% of these were employed. Educational status and being accompanied to the first clinic visit were favorable predictors of outcome. Type of spell was also a predictor: motionless spells had a more favorable outcome. Other variables were not predictors of outcome. These data may help with counseling and resource allocation for patients with PNES.

Hashimoto's encephalopathy: documentation of mesial temporal seizure origin by ictal EEG.

Hashimotos encephalopathy is a chronic relapsing and remitting encephalopathy associated with antithyroid antibodies. Seizures are a frequent manifestation, but are not well characterized in the literature with respect to their onset. We describe a 48-year-old patient with recurrent encephalopathy and seizures, and elevated antithyroid antibodies. One seizure was documented with video-EEG monitoring using scalp and sphenoidal electrodes. The ictal discharge originated in the left mesial-basal temporal region. MRI showed an increased T2 signal in the white matter of the centrum semiovale, but no temporal pathology. Symptoms resolved after treatment with prednisone and azathioprine. Hashimotos encephalopathy should be considered in patients with unexplained encephalopathy and seizures, including those originating in the temporal lobe.

Aphasic or amnesic status epilepticus detected on PET but not EEG

Purpose:  To describe five patients with ictal aphasia and one patient with ictal amnesia, who had focal positron emission tomography (PET) hypermetabolism but no clear ictal activity on electroencephalography (EEG).

Management of new-onset epilepsy in the elderly

The incidence of new-onset epilepsy is high among elderly patients. Seizures can present differently to and with more subtle semiology than those in younger adults. This difference in presentation frequently poses a diagnostic challenge. Elderly patients also often have comorbidities, are usually on multiple medications that can interact, have altered medication pharmacokinetics, and tend to be particularly sensitive to adverse effects of medication. Seizures in the elderly tend, however, to respond better to antiepileptic drugs than those in younger individuals, and can often be appropriately controlled with monotherapy. After the diagnosis of epilepsy is confirmed, treatment should be started with a single medication at a low dose, with subsequent gradual upward titration until seizures are controlled. First-generation antiepileptic drugs should be avoided in the elderly in view of poor tolerability. A large trial has shown that lamotrigine and gabapentin are better tolerated than carbamazepine. In elderly patients whose seizures remain uncontrolled on antiepileptic medications, surgery can be considered if excellent results are predicted and the risks are low.

Surgical trial investigating nocturnal gastroesophageal reflux and sleep (STINGERS)

Background: Nocturnal reflux is important in the pathogenesis of esophagitis. The relationship between reflux and sleep is poorly understood, although data support both paradigms of nocturnal reflux causing arousal and nocturnal arousal allowing reflux. Furthermore, the effect of fundoplication on sleep is unknown. Methods: Seven volunteers and 11 patients with gastroesophageal reflux disease (GERD) and nocturnal symptoms were studied with esophageal pH and polysomnography at baseline and at 8 to 10 weeks follow-up evaluation, with patients undergoing interval fundoplication. Gastrointestinal and sleep questionnaires were completed before each study. Results: Questionnaire data between the groups showed differences at baseline, which were eliminated by surgery. No objective differences in sleep were observed between the groups at baseline or at follow-up evaluation. However, the patient group significantly increased the fraction of the night spent in deeper sleep (49.6% vs 58.3%; p = 0.022). Reflux events were associated with arousals in sleep. Conclusions: Fundoplication improves both subjective and objective sleep quality in patients with nocturnal GERD symptoms.

Patients visiting the emergency room for seizures: Insurance status and clinic follow-up

PURPOSE Epilepsy is a chronic condition that is best treated in the outpatient clinic setting. However, many epilepsy patients use the hospital emergency room (ER) as a primary resource for seizure management. We studied characteristics of these patients in comparison with patients attending an epilepsy clinic. METHODS We reviewed ER data of patients seen in 2002 and 2003 for seizures, in Vanderbilt University Hospital (VUH) and Metro Nashville General Hospital (MNGH), seeking to identify patients who had visited the emergency room more than once. We collected demographic and insurance information on these patients and identified those who followed up in the epilepsy clinic. RESULTS There were 1005 patients who visited the VUH ER and 205 the MNGH ER for seizures. Patients visiting the ER for seizures were less likely to be insured than epilepsy patients followed in the clinic, in both institutions. The proportion of patients visiting the ER more than once was 15.2% at VUH and 29.2% at MNGH. Among these patients, 3.2% at VUH and 26.7% at MNGH were uninsured. Clinic follow-up occurred in 68.6% of VUH and 13.3% of MNGH repeat ER visitors. Combining institutions, insured patients were much more likely to follow-up in the clinic. DISCUSSION Repeated use of the ER for seizures was more common in the county hospital, where the proportion of uninsured patients was also higher. Patients visiting the county hospital ER repeatedly tend not to follow-up in the neurology clinic. This element of disparity of care requires further attention.

Psychogenic pseudosyncope: diagnosis and management.

Psychogenic pseudosyncope (PPS) is the appearance of transient loss of consciousness (TLOC) in the absence of true loss of consciousness. Psychiatrically, most cases are classified as conversion disorder, which is hypothesized to represent the physical manifestation of internal stressors. The incidence of PPS is likely under-recognized and the disorder is under investigated in the unexplained syncope population, yet it can be diagnosed accurately with a focused history and confirmed with investigations including head-up tilt testing (HUTT), electroencephalogram (EEG; sometimes combined with video) or, in some centers, transcranial Doppler (TCD). Patients are more likely to be young females with an increased number of episodes over the past 6months. They frequently experience symptoms prior to their episodes including light-headedness, shortness of breath and tingling. Conversion disorder is associated with symptomatic chronicity, increased psychiatric and physical impairment, and diminished quality of life. Understanding the epidemiology, biological underpinnings and approach to diagnosis of PPS is important to improve the recognition of this disorder so that patients may be managed appropriately. The general treatment approach involves limiting unnecessary interventions, providing the patient with needed structure, and encouraging functionality. While there are no treatment data available for patients with PPS, studies in related conversion disorder populations support the utility of psychotherapy. Psychotropic medications should be considered in patients with comorbid psychiatric disorders.

Epilepsy and the Impact of an Epileptology Clinic for Patients with Mental Retardation and Associated Disabilities in an Institutional Setting

Summary:  Purpose: Epilepsy is a common problem in institutionalized patients with multiple handicaps. Limited data exist on the characteristics of epilepsy in this patient population and the impact of systematic evaluation by an epilepsy service.