Tanvir U. Syed

Can Semiology Predict Psychogenic Nonepileptic Seizures? A Prospective Study

Reducing health and economic burdens from diagnostic delay of psychogenic nonepileptic seizures (PNES) requires prompt referral for video electroencephalography (VEEG) monitoring, the diagnostic gold standard. Practitioners make VEEG referrals when semiology suggests PNES, although few semiological signs are supported by well‐designed studies, and most VEEG studies neglect to concurrently measure how accurately seizure witnesses can ascertain semiology. In this study, we estimate the value of eyewitness‐reported and video‐documented semiology for predicting PNES, and we measure accuracy of eyewitness reports.

Low-frequency electrical stimulation of a fiber tract in temporal lobe epilepsy.

Surgical resection of the temporal lobe is an effective treatment for medically intractable temporal lobe epilepsy, but can cause memory impairment. Deep brain stimulation in epilepsy has targeted gray matter structures using high frequencies, but achieved limited success. We tested the hypothesis that low‐frequency stimulation of the fornix reduces interictal epileptiform discharges and seizures in patients with intractable mesial temporal lobe epilepsy, without affecting memory.

Do observer and self-reports of ictal eye closure predict psychogenic nonepileptic seizures?

Purpose: Diagnostic delay in distinguishing psychogenic nonepileptic seizures (PNES) from epileptic seizures may result in unnecessary therapeutic interventions and higher health care costs. Previous studies demonstrated that video‐recorded eye closure is associated with PNES. The present study prospectively assessed whether observer or self‐report of eye closure could predict PNES, prior to video‐EEG monitoring.

Modern technology calls for a modern approach to classification of epileptic seizures and the epilepsies

In the last 10–15 years the ILAE Commission on Classification and Terminology has been presenting proposals to modernize the current ILAE Classification of Epileptic Seizures and Epilepsies. These proposals were discussed extensively in a series of articles published recently in Epilepsia and Epilepsy Currents. There is almost universal consensus that the availability of new diagnostic techniques as also of a modern understanding of epilepsy calls for a complete revision of the Classification of Epileptic Seizures and Epilepsies. Unfortunately, however, the Commission is still not prepared to take a bold step ahead and completely revisit our approach to classification of epileptic seizures and epilepsies. In this manuscript we critically analyze the current proposals of the Commission and make suggestions for a classification system that reflects modern diagnostic techniques and our current understanding of epilepsy.

Phrenic nerve conduction studies in spinal cord injury: Applications for diaphragmatic pacing

The diaphragm pacing system (DPS) is a minimally invasive alternative to mechanical ventilation in patients with quadriplegia due to cervical myelopathy primarily caused by high cervical spinal cord injury. We evaluated 36 patients, 29 of whom had traumatic spinal cord injury, two who had a history of remote meningitis and demyelinating disease, and five who had cervical myelopathies of unknown etiology. Phrenic nerve conduction studies were performed with simultaneous fluoroscopic observation of diaphragm excursion to assess diaphragm viability. In the preoperative evaluation, diaphragm compound muscle action potentials (CMAPs) were recorded only when the diaphragm moved on fluoroscopy with ipsilateral stimulation. Twenty‐six patients who were determined to have a viable diaphragm underwent DPS. Following DPS the primary outcome was the time (hours per day) that patients were able to pace and stay off the ventilator. Of 26 implanted patients, 96% (25 patients) were able to pace and tolerate being off the ventilator for more than 4 h per day. This study demonstrates that the presence of a diaphragm CMAP is associated with diaphragm movement observed by fluoroscopy in cervical myelopathy. In addition, DPS can help patients with cervical spinal cord injury to breathe unassisted by a ventilator. Muscle Nerve 38: 1546–1552, 2008

A self-administered screening instrument for psychogenic nonepileptic seizures

Background: Delay in distinguishing psychogenic nonepileptic seizures (PNES) from epilepsy may result in significant health and economic burdens. Screening tools are needed to facilitate earlier identification of patients with PNES, thereby maximizing cost-effective use of video electroencephalography (VEEG), the expensive gold standard for differentiating PNES from epilepsy. We developed and prospectively validated a self-administered PNES screening questionnaire using variables known to distinguish PNES from epilepsy patients. Methods: Adults referred for inpatient VEEG monitoring at two epilepsy centers were prospectively invited to complete a preliminary 209-item questionnaire assessing demographic, clinical, seizure-related, and psychosocial information that appeared in the literature as potentially useful indicators of PNES. A hybrid neural–bayesian classifier was trained to predict PNES using a sample at one center, and was prospectively validated on a separate set of naive patients from both centers. Results: Of 211 enrolled subjects from the training center, 181 met the study criteria for either PNES (n = 48, 27%), epilepsy (n = 116, 64%), or coexisting PNES and epilepsy (n = 17, 9%). Variable reduction procedures identified 53 questionnaire items that were necessary to accurately predict PNES diagnosis. The hybrid classifier predicted PNES diagnosis with 94% sensitivity and 83% specificity at the training center, and 85% sensitivity and 85% specificity at the second center (n = 46; 17 PNES, 26 epilepsy, 3 with coexisting PNES and epilepsy). Conclusions: We developed and prospectively validated a self-administered psychogenic nonepileptic seizure screening questionnaire that could hasten referral for video electroencephalography and reduce the health and economic burdens from delayed diagnosis or misdiagnosis.

Risk factors associated with death in in-hospital pediatric convulsive status epilepticus

Objective To evaluate in-patient mortality and predictors of death associated with convulsive status epilepticus (SE) in a large, multi-center, pediatric cohort. Patients and Methods We identified our cohort from the KID Inpatient Database for the years 1997, 2000, 2003 and 2006. We queried the database for convulsive SE, associated diagnoses, and for inpatient death. Univariate logistic testing was used to screen for potential risk factors. These risk factors were then entered into a stepwise backwards conditional multivariable logistic regression procedure. P-values less than 0.05 were taken as significant. Results We identified 12,365 (5,541 female) patients with convulsive SE aged 0–20 years (mean age 6.2 years, standard deviation 5.5 years, median 5 years) among 14,965,571 pediatric inpatients (0.08%). Of these, 117 died while in the hospital (0.9%). The most frequent additional admission ICD-9 code diagnoses in addition to SE were cerebral palsy, pneumonia, and respiratory failure. Independent risk factors for death in patients with SE, assessed by multivariate calculation, included near drowning (Odds ratio [OR] 43.2; Confidence Interval [CI] 4.4–426.8), hemorrhagic shock (OR 17.83; CI 6.5–49.1), sepsis (OR 10.14; CI 4.0–25.6), massive aspiration (OR 9.1; CI 1.8–47), mechanical ventilation >96 hours (OR9; 5.6–14.6), transfusion (OR 8.25; CI 4.3–15.8), structural brain lesion (OR7.0; CI 3.1–16), hypoglycemia (OR5.8; CI 1.75–19.2), sepsis with liver failure (OR 14.4; CI 5–41.9), and admission in December (OR3.4; CI 1.6–4.1). African American ethnicity (OR 0.4; CI 0.2–0.8) was associated with a decreased risk of death in SE. Conclusion Pediatric convulsive SE occurs in up to 0.08% of pediatric inpatient admissions with a mortality of up to 1%. There appear to be several risk factors that can predict mortality. These may warrant additional monitoring and aggressive management.

The Safety of Controlled Hypotension for Shoulder Arthroscopy in the Beach-Chair Position

BACKGROUND The safety of controlled hypotension during arthroscopic shoulder procedures with the patient in the beach-chair position is controversial. Current practice for the management of intraoperative blood pressure is derived from expert opinion among anesthesiologists, but there is a paucity of clinical data validating their practice. The purpose of this study was to evaluate the effect of controlled hypotension on cerebral perfusion with use of continuous electroencephalographic monitoring in patients undergoing shoulder arthroscopy in the beach-chair position. METHODS Fifty-two consecutive patients who had undergone shoulder arthroscopy in the beach-chair position were enrolled prospectively in this study. All patients underwent preoperative blood pressure measurements, assignment of an American Society of Anesthesiologists (ASA) grade, and a preoperative and postoperative neurological and Mini-Mental State Examination (MMSE). The target systolic blood pressure for all patients was 90 to 100 mm Hg during surgery. Continuous intraoperative monitoring was performed with standard ASA monitors and a ten-lead portable electroencephalography monitor. Real-time electroencephalographic monitoring was performed by an attending-level neurophysiologist. RESULTS All patients violated at least one recommended limit for blood pressure reduction. The average decrease in systolic blood pressure and mean arterial pressure from baseline was 36% and 42%, respectively. Three patients demonstrated ischemic changes on electroencephalography that resolved with an increase in blood pressure. No adverse neurological sequelae were observed in any patient on the basis of the MMSE. CONCLUSIONS This study provides the first prospective data on global cerebral perfusion during shoulder arthroscopy in the beach-chair position with use of controlled hypotension. Our study suggests that patients may be able to safely tolerate a reduction in blood pressure greater than current recommendations. In the future, intraoperative cerebral monitoring may play a role in preventing neurological injury in patients undergoing shoulder arthroscopy in the beach-chair position.

National Institutes of Health Stroke Scale Assists in Predicting the Need for Percutaneous Endoscopic Gastrostomy Tube Placement in Acute Ischemic Stroke

Percutaneous endoscopic gastrostomy (PEG) tubes are commonly needed for early nutrition in patients with acute ischemic stroke. We evaluated the relationship between the NIH Stroke Scale (NIHSS) score and the need for PEG tube placement. Patients with acute ischemic stroke were included in this study. We collected information on patient demographics, stroke severity as indicated by the NIHSS, and risk factors for vascular disease. We ascertained the swallowing evaluation and PEG tube placement during the same hospitalization. A hierarchical optimal classification tree was determined for the best predictors. A total of 187 patients (mean age, 67.2 years) were included, only 33 (17.6%) of whom had a PEG tube placed during the course of hospitalization. Those who had the PEG were slightly older (73.8 vs 65.8 years), had severe stroke (median NIHSS score, 18 vs 4), and a longer hospital stay (median 12 vs 4 days). Independent predictors for PEG placement included bulbar symptoms at onset, higher NIHSS score, stroke in the middle cerebral artery distribution, and aspiration pneumonia. Hierarchical analysis showed that patients with aspiration pneumonia and NIHSS score >or=12 had the highest likelihood (relative risk [RR] = 4.67; P < .0001) of requiring a PEG tube. In the absence of pneumonia, NIHSS score >or=16 yielded a moderate likelihood of requiring PEG (RR = 1.80; P < .0001). Our findings indicate that the presence of pneumonia and high NIHSS score are the best predictors for requiring PEG tube insertion in patients with ischemic stroke. These findings may have benefits in terms of early decision making, shorter hospitalization, and possible cost savings.

Sleep-wake patterns of seizures in children with lesional epilepsy.

This study examined diurnal patterns of seizures and their occurrence during wakefulness and sleep in children with lesional focal epilepsy. We reviewed 332 consecutive children with lesional focal epilepsy and video-electroencephalogram monitoring during a 3-year period. Data were analyzed in relationship to clock time, wakefulness/sleep, and seizure localization. The distribution of lesions in 66 children (259 seizures) included mesial temporal, 29%; neocortical temporal, 18%; frontal, 29%; parietal, 13.5%; and occipital, 12%. Seizures in patients with frontal lesions occurred mostly during sleep (72%). Seizures in mesial temporal (64%), neocortical temporal (71%), and occipital (66%) lesional epilepsy occurred mostly during wakefulness. Temporal lobe seizures occurred more frequently during wakefulness (66%), compared with extratemporal seizures (32%) (odds ratio, 2.67; 95% confidence interval, 1.61-4.42). Temporal lobe seizures peaked between 9:00 am and noon and 3:00-6:00 pm, whereas extratemporal seizures peaked between 6:00-9:00 am. Sleep, not clock time, provides a more robust stimulus for seizure onset, especially for frontal lobe seizures. Temporal lobe seizures are more frequent during wakefulness than are extratemporal seizures. Circadian patterns of seizures may provide additional diagnostic and treatment options, such as differential medication dosing and sleep-schedule adjustments.