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Biomedical subjects

E M Mizrahi

Publications and source records attributed to E M Mizrahi.

At least 19 recordsLinked to original sources
PubMed2001

Risk factors for neonatal seizures: a population-based study, Harris County, Texas, 1992-1994.

Risk factors for neonatal seizures were evaluated in 116,048 infants born between 1992 and 1994 to residents of Harris County, Texas; 207 of these infants were diagnosed with clinical neonatal seizures. Information was obtained from the infant's birth certificate to assess the relation between seizures and birth weight, gender, ethnicity, place of birth, mother's age, method of delivery, parity, and multiple births. These factors were evaluated by univariate and multivariate analysis using logistic regression. For preterm infants, a birth weight of <1,500 g was the strongest risk factor (relative risk (RR) = 9.1, 95% confidence interval (CI): 4.7, 17.5), followed by birth in a private/university hospital (RR = 2.8, 95% CI: 1.5, 5.0) and male gender (RR = 1.8, 95% CI: 1.0, 3.4). For term infants, significant risk factors included birth by cesarean section (RR = 2.2, 95% CI: 1.5, 3.2), small birth weight for gestational age (RR = 1.9, 95% CI: 1.2, 2.9), birth in a private/university hospital (RR = 1.8, 95% CI: 1.1, 3.0), and maternal age of 18-24 compared with 25-29 years (RR = 1.6, 95% CI: 1.1, 2.3). Birth by assisted vaginal delivery and primiparity were marginally significant for term infants. Birth weight is a significant risk factor for neonatal seizures. The role of perinatal complications warrants further evaluation.

Birth Weight↗
PubMed2001

Extraction of motion strength and motor activity signals from video recordings of neonatal seizures.

This paper presents two methods developed to extract quantitative information from video recordings of neonatal seizures in the form of temporal motion strength and motor activity signals. Motion strength signals are extracted by measuring the area of the body parts that move during the seizure and the relative speed of motion using a combination of spatiotemporal subband decomposition of video, nonlinear filtering, and segmentation. Motor activity signals are extracted by tracking selected anatomical sites during the seizure using a modified version of a feature-tracking procedure developed for video, known as the Kanade-Lucas-Tomasi (KLT) algorithm. The experiments indicate that the temporal signals produced by the proposed methods provide the basis for differentiating myoclonic from focal clonic seizures and distinguishing these types of neonatal seizures from normal infant behaviors.

Algorithms↗
PubMed2000

Neonatal seizures: early-onset seizure syndromes and their consequences for development.

The determination of the developmental consequences of seizure syndromes in the neonate is based upon a number of factors which include: understanding of the clinical and electroencephalographic (EEG) features of neonatal seizures; current theories of the mechanisms by which neonatal seizures are generated; a current classification of neonatal seizures; potential etiologic and risk factors for seizures; and therapies. In addition, different seizure types, mechanisms of generation and etiologies of cerebral dysfunction may vary with conceptional age of the infant. There are a few distinct neonatal epileptic syndromes, which are rare, have been well described: benign neonatal convulsions; benign neonatal familial convulsions; early myoclonic encephalopathy and early infantile epileptic encephalopathy. The prognosis for the first two is relatively good while the outcome for the other two with encephalopathy is catastrophic. However, the majority of neonatal seizures occur as acute, reactive events in association with a wide range of etiologic factors. These etiologic factors, as well as those of the more traditionally defined syndromes, are the main determinants of eventual developmental outcome of neonates who experience seizures. Although experimental data suggests that some epileptic seizures eventually may have physiological, histological, metabolic, or behavioral consequences, there is yet direct evidence in humans to suggest that the occurrence of seizures themselves in the neonate is the main determinant of long-term outcome.

Acute Disease↗
PubMed1999

Incidence of neonatal seizures in Harris County, Texas, 1992-1994.

This study estimated the incidence of clinical neonatal seizures among infants born between 1992 and 1994 in Harris County, Texas, a county with a large and ethnically diverse population. Infants with neonatal seizures were ascertained from four sources: hospital discharge diagnoses, birth certificates, death certificates, and a study of neonatal seizures conducted concurrently with this study at a large tertiary care center in Houston, Texas. There were 207 cases of clinical neonatal seizures among 116,048 live births (an incidence of 1.8 per 1,000 live births). The incidence was highest among infants weighing less than 1,500 g (19/1,000) and decreased as birth weight increased. There was no significant difference in incidence by ethnicity. Twenty-six percent of the seizures (54/207) occurred after the infants had been discharged from the hospital where they were born. The incidence of neonatal seizures in Harris County was lower than the incidence reported recently for Fayette County, Kentucky, for 1985-1989 (3.5/1,000) and for Newfoundland, Canada, for 1990-1995 (2.5/1,000), but was higher than the incidence estimated for Rochester, Minnesota, for 1935-1984 (1/1,000).

Age Factors↗
PubMed1999

Pediatric electroencephalographic video monitoring.

Pediatric EEG video monitoring is based on methodology that is similar to that used for monitoring of adults, although there are important differences. In addition, the range of clinical events suspected of being seizures in the pediatric population is quite different from those in adults and, within childhood, is age-specific. Thus, the clinical utility of monitoring in neonates, infants, and children is based on an understanding of the full range of normal and abnormal epileptic and nonepileptic events that may occur in this age group. Similarly, the findings of the EEG are age-dependent and must be considered when they are interpreted as part of the monitoring study and when they are correlated with clinical events captured on video. Monitoring can be utilized in the detection, characterization, and quantification of various types of seizure disorders in children. The most effective application of monitoring, which can ensure the greatest chance for clinically useful information, occurs when monitoring is well-planned; utilizes appropriate EEG and polygraphic-physiologic parameters; incorporates optimal video recording techniques; maintains age-appropriate recording environments within the context of medical necessity; and is conducted in a laboratory with adequate support staff. Pediatric monitoring has been effective in the clinical management of neonatal seizures, infantile spasms, other seizure types in infancy, epilepsy in late childhood, and in the evaluation of pediatric patients of all ages for epilepsy surgery.

Age Factors↗
PubMed1999

Acute and chronic effects of seizures in the developing brain: lessons from clinical experience.

Seizures in the neonate are often considered a form of status epilepticus (SE) because they are relatively prolonged, difficult to control with antiepileptic drugs (AEDs), and may be associated with significant morbidity and mortality. Despite their clinical importance, there is still no clear understanding of how seizures may affect the developing brain. Although both basic neuroscience and clinical research have addressed these issues, there are difficulties in the design and analysis of each type of investigation. Animal studies should reflect the human condition, the most relevant studies being those that consider neocortical rather than hippocampal seizures. Clinical investigations should be based on precise, age-specific definitions of seizures of epileptic origin and of SE. Treatment strategies should be standardized with defined rationale and end points. Outcome measures are best when defined and quantifiable. The relative effects of underlying CNS injuries that coexist with the onset of neonatal seizures may be difficult to differentiate from the effects of the seizures themselves or their treatment. Current clinical studies suggest that the overriding factors in determining the outcome of neonates with seizures are the cause, the degree, and the distribution of brain injury at the time of seizure occurrence. However, such studies have limitations and may not yet employ methodology sensitive enough to detect a full range of adverse effects of seizures themselves.

Brain↗
PubMed1998

Pathologic basis of the symptomatic epilepsies in childhood.

The epilepsies in childhood are classified as primary (or idiopathic) and secondary (or symptomatic). The primary epilepsies account for two thirds of all childhood epilepsies and are presumed to be genetically determined. In the remaining one third of cases, a neuropathologic lesion can be identified. This paper summarizes the etiologies of the symptomatic epilepsies. They are classified according to the pathologic processes; malformative, metabolic, neoplastic and phakomatoses, hypoxic-ischemic, infectious, and of unknown pathologic process.

Brain Neoplasms↗
PubMed1997

Evaluation of an automatic seizure detection method for the newborn EEG.

In another publication, we described a set of methods for automatic detection of EEG seizures in the newborn. We describe here the evaluation of these methods using a completely new set of data, which were not used in developing the method. This testing data set consisted of recording from 54 patients, lasting an average of 4.4 h. Recordings had 8-16 channels and were obtained, in approximately equal numbers, from 3 institutions in Canada, the USA and Australia. Recording conditions varied from short recordings fully attended by a technologist to overnight recordings largely unattended. The average seizure detection rate was 69% (77%, 53%, 84% in the 3 institutions). False detections occurred at the average rate of 2.3/h (4.1, 1.0, 2.7 in the 3 institutions), with fluctuations that reflected largely the technical quality and level of supervision of the recordings. The results are similar to those obtained in the commonly used method of epilepsy monitoring in adults and allow us to envisage clinical application.

Electroencephalography↗
PubMed1997

Continuous electroencephalographic monitoring and selective shunting reduces neurologic morbidity rates in carotid endarterectomy.

PURPOSE: The role of continuous electroencephalographic (EEG) monitoring during carotid endarterectomy was evaluated in this retrospective review. METHODS: We analyzed data from 902 consecutive carotid endarterectomy procedures performed with vein patch angioplasty. In 591 operations from 1980 to 1988 we did not use intraoperative EEG monitoring or shunting (non-EEG group). Continuous intraoperative EEG monitoring and selective shunting were used in 311 procedures from 1988 to 1994 (EEG group). The patients' mean age was higher in the EEG group (68.8 years; range, 41 to 87 years) than in the non-EEG group (66.2 years; range, 34 to 90 years; p < 0.001). There was also a significantly higher incidence of hypertension (56.2% vs 41.9%) and redo operations (5.4% vs 2.54%) in the EEG group than in the non-EEG group (p < 0.05). The operative technique was identical in both groups. We defined a significant EEG change as a greater than 50% reduction of the amplitude of the faster frequencies, a persistent increase of delta activity, or both. RESULTS: In the EEG group, acute EEG changes occurred in 40 patients (12.8%); 31 (77.5%) unilateral and ipsilateral to the operated carotid artery, and nine (22.5%) bilateral. In five patients (12.5%) the changes correlated with an intraoperative episode of hypotension, and after normal blood pressure was restored the EEG returned to normal. In 35 procedures (87.5%) a carotid shunt was inserted. In 33 of those patients the EEG returned to baseline, in one patient there was a significant improvement, and in one patient the EEG changes persisted. Postoperative hospital strokes occurred in one patient (0.32%) in the EEG group and in 13 patients (2.19%) in the non-EEG group (p < 0.05). All strokes (n = 14) were ipsilateral to the operated carotid artery. Of the 13 strokes in the non-EEG group nine were major and four were minor. The one stroke in the EEG group was embolic in origin and occurred before carotid cross-clamping; it was associated with profound EEG changes that did not reverse after placement of a shunt. In the total group (n = 902), intraoperative EEG monitoring was inversely associated with postoperative stroke (p < 0.05). CONCLUSION: The overall neurologic morbidity rate was significantly lower in the EEG group than in the non-EEG group, therapy demonstrating the value of intraoperative EEG monitoring in carotid endarterectomy.

Adult↗
PubMed1996

Avoiding the pitfalls of EEG interpretation in childhood epilepsy.

The accurate interpretation of the electroencephalogram (EEG) of infants and children being evaluated for suspected epilepsy is based on the appreciation of normal and expected age-dependent characteristics, an awareness of the significance of both epileptiform and non-epileptiform activity, and the correlation of epileptiform abnormalities with clinical findings. Avoiding the pitfalls of pediatric EEG interpretation include the recognition of such normal EEG features in wakefulness as posterior slow waves of youth, mu rhythm, and lambda waves. In addition, the understanding of age-dependent characteristics of EEG state-changes is essential, such as: monorhythmic and paroxysmal hypnagogic hypersynchrony, special features of vertex transients and sleep spindles, positive occipital sharp transients, initial arousal responses and post-arousal hypersynchrony. The EEG response to activation procedures such as hyperventilation and photic stimulation may also be a source of confusion. Patterns of uncertain diagnostic significance also may be present in children, including 14- and 6-Hz bursts and rhythmic temporal theta bursts of drowsiness (the so-called psychomotor variant). Some nonepileptiform EEG abnormalities may also be misinterpreted as epileptiform. The determination of the clinical significance of spike foci and generalized abortive spike-and-wave may pose more of a problem as a potential pitfall than the identification by visual analysis of these interictal discharges. Another problem posed to the electroencephalographer is the determination of the EEG response to antiepileptic drug therapy including effect on spike foci, generalized spike-and-wave and electrical seizure activity, and effect on background activity. The recognition of the differences between the EEG of children and adults will provide the basis for more accurate interpretation and assist the electroencephalographer in avoiding the identification of normal, age-dependent features as epileptiform.

Adolescent↗
PubMed1994

Glial cell nuclear hypertrophy in complex partial seizures.

The white matter of resected temporal lobes from patients with intractable complex partial seizures shows increased cellularity which appears to be related to glia and neurons. This study, using quantitative methods, defines an increase in glial cell numbers and a significant increase in glial nuclear size within a defined area of white matter in the lateral temporal lobe. Evaluation was made on specimens from ten patients with complex partial seizures compared with two patients with non-epileptic brain lesions and five autopsy patients with no neurologic disease. The importance of recognizing these alterations in glia and the possible relevance to the pathoetiology of epilepsy are discussed.

Adolescent↗
PubMed1994

Seizure disorders in children.

During the past year, a number of issues concerning the diagnosis and management of seizure disorders in children were addressed in large clinical studies and in carefully developed position papers. These issues included the syndrome of benign familial neonatal convulsions, the treatment and prognosis of infantile spasms, the prevention of febrile seizures with oral diazepam, the treatment of status epilepticus, and the identification of predictors of outcome of childhood epilepsy that may impact therapeutic decisions. Although the findings of some of these studies were controversial, each presents data that can be useful in the clinical assessment and treatment of children with these disorders.

Child↗
PubMed1994

Electroencephalographic-video monitoring in neonates, infants, and children.

Electroencephalographic (EEG)-video monitoring is a valuable tool in the evaluation and management of neonates, infants, and children suspected of having seizures or those with confirmed epilepsy. Monitoring may provide the basis for detection, characterization, and quantification of seizures in each of these age groups. The basic functional components of monitoring include: EEG, polygraphic measures, video, and synchronization devices that assure that all recorded modalities can be precisely correlated in time. Monitoring techniques may vary depending on patient age, clinical condition, and clinical questions to be addressed. Specially designed instrumentation is required to perform monitoring; however, the role of the technologist is central in conducting a study with maximum clinical yield in the most efficient manner. The clinical neurophysiologist must recognize the specific objectives of each monitoring study and appreciate the age-dependent features of the EEG and the types of clinical paroxysmal events that may occur at different ages. Neonates, infants, and older children all demonstrate special features to be considered in the conduct and analysis of EEG-video monitoring.

Anticonvulsants↗
PubMed1989

Hypothermic-induced electrocerebral silence, prolonged circulatory arrest, and cerebral protection during cardiovascular surgery.

Certain cardiovascular operations require cardiopulmonary bypass and prolonged circulatory arrest to provide an adequate operative field. Profound hypothermia is induced to protect brain function during these periods without cerebral perfusion. Because peripheral body temperatures may not be valid indicators of brain temperature, we conducted this study to establish an alternative, more reliable, method of determining the appropriate level of hypothermia. We measured peripheral body temperatures from 3 sites (rectum, nasopharynx, and esophagus) at the onset of hypothermic-induced electrocerebral silence (ECS) in the intraoperative electroencephalogram (EEG) of 56 adults undergoing cardiovascular procedures. The EEG in most patients showed a characteristic progression of changes from its normal resting state during cooling. Gradual depression and slowing of background rhythms was followed by generalized, periodic, slow-wave transients, prolongation of the intervals between the transients, and then the onset of ECS. In cases in which the slow-wave transients did not appear, the initial depression and slowing of background activity gradually progressed to ECS. No consistent relationship was found between peripheral body temperatures at various sites and the onset of ECS. Using EEG-guided hypothermia, there was low morbidity and mortality. These data suggest that ECS is a safe and reliable guide for determining the appropriate level of hypothermia during cardiovascular procedures.

Adult↗
PubMed1989

Consensus and controversy in the clinical management of neonatal seizures.

Neonatal seizures may be characterized and classified according to their clinical features and presumed pathophysiology. There is evidence to suggest that seizures may either be epileptic in origin or initiated and mediated by nonepileptic mechanisms. Therapeutic decisions may be based on bedside assessment of the pathophysiology of observed seizures. Although EEG/video monitoring plays a role in the management of neonatal seizures, clinical evaluation of the seizures may provide initial data critical to decisions concerning immediate management.

Electroencephalography↗