Spike detection. I. Correlation and reliability of human experts.

A panel of 5 experienced electroencephalographers detected spikes in EEG trials from 40 epilepsy patients and 10 control subjects. 1952 spikes were detected, and detailed attribute scores were recorded. Statistics from the theory of measurement error are utilized to quantify the reliability and difficulty of the study. An extension of the Pearson correlation coefficient, called the detection correlation coefficient, is derived and used in recognition of the fact that readers agree on numerous non-spike regions. Spike perception is modeled with both dichotomous and continuous values. as expected, the study reliability is higher when using the continuous values. Standard sensitivity and specificity definitions are extended and applied to continuous-valued spike perception. A database of "panel scores" was created from the 5 reader scorings by merging spikes within 75 msec on each side. The average inter-reader correlation is 0.79 with a corresponding reliability of 0.95. Average spike attributes are calculated, and the resulting database can serve as a "gold standard" for testing computer algorithms or other readers.

Presumed central nervous system Whipple's disease in a child: case report.

Whipple's disease is a rare, chronic, multisystem illness that is pathologically characterized by the accumulation of macrophages in the involved tissue that have a positive periodic acid-Schiff reaction. It is typically seen in middle-aged white men, and only four cases involving persons younger than 15 years of age have been reported. CNS Whipple's disease without intestinal manifestations is rare; only six cases have been reported in the literature, all involving adults. We report the case of a young boy with clinical, laboratory, radiographic, and pathological signs and symptoms consistent with CNS Whipple's disease who responded to therapy with trimethoprimsulfamethoxazole.

Prognostic value of EEG in neonatal meningitis: retrospective study of 29 infants.

Neonatal meningitis is associated with significant neurologic sequelae. Previous studies from our laboratory and others demonstrated electroencephalography (EEG) to be a useful tool in predicting long-term neurologic outcome in at-risk neonates. We, therefore, retrospectively studied 29 infants with culture-proved neonatal meningitis who died in the neonatal period or survived to follow-up at a mean of 34.4 months. Seventy-five EEGs were obtained during the acute phase of infection; the degree of EEG background abnormality proved to be an accurate predictor of outcome. Infants who had normal or mildly abnormal backgrounds had normal outcomes, whereas those with markedly abnormal EEGs died or manifested severe neurologic sequelae at follow-up. When the EEG was considered with the presence or absence of seizures and the level of consciousness, an accurate prediction of neurologic outcome was obtained in 27 infants (93%). Although the EEG patterns were generally nonspecific, some abnormalities, such as positive rolandic sharp waves, persistent hemispheric or focal voltage attenuation, suggested more specific pathology (i.e., deep white matter necrosis, large-vessel infarction and abscess, respectively). EEG was also valuable for the recognition of subtle and subclinical seizures. Therefore, we conclude that EEG is a valuable tool for predicting the long-term prognoses of infants with neonatal meningitis.

Unique EEG pattern (comb-like rhythm) in neonatal maple syrup urine disease.

A unique electroencephalographic pattern (the comb-like rhythm) is described in an infant with neonatal (classic) maple syrup urine disease. This pattern consists of bursts and runs of 5-7 Hz primarily monophasic negative (mu-like) activity in the central and central-parasagittal regions during wakefulness and sleep with the most abundant bursts occurring during quiet (non-REM) sleep. This pattern appeared during the first 2 weeks of life and was absent in the recording obtained 40 days after the initiation of dietary therapy. In the proper clinical setting this electroencephalographic pattern is diagnostic of maple syrup urine disease and can be distinguished from similar patterns occurring in normal infants and those with other encephalopathies.

Winner of the Brazier Award. The dysmature EEG pattern in infants with bronchopulmonary dysplasia and its prognostic implications.

Bronchopulmonary dysplasia (BPD) is a chronic lung disease which occurs in premature infants who require prolonged mechanical ventilation and supplemental oxygen support. Infants with severe BPD often have neurological sequelae or early mortality. We have observed a pattern of delay in the maturation of cerebral electrical activity of some infants who have more severe forms of BPD. This delayed electroencephalographic (EEG) maturation or 'dysmaturity' is best recognized when the conceptional age (CA) of the premature infant approaches term and is characterized by the presence of EEG activity which normally disappears in premature infants by 36-37 weeks CA. We studied 36 infants with BPD who had serial EEGs and at least 1 EEG between 37 and 42 weeks CA. Dysmature EEGs were found in 23 infants. Unfavorable outcomes were found in 83% (19/23) of these infants, including 22% (5/23) mortality, and 61% (14/23) abnormal or suspect neurological outcome. Thirteen infants had EEGs which lacked dysmature features. Of these infants, 62% (8/13) had normal neurological outcome, and 38% (5/13) had unfavorable outcome (1 death, 2 abnormal, and 2 suspect). In 2 of the 5 infants with unfavorable outcomes without dysmature EEGs, a suppression-burst pattern (known to be associated with neurological sequelae) was found. The presence of dysmature patterns in the near-term or term EEG was associated with significantly less favorable outcome (P = 0.01). Several other clinical factors which were associated with dysmature EEGs are also discussed.

Electrophysiological brain maturation in premature infants: an historical perspective.

The EEG is an excellent method for measuring brain maturation in premature neonates. Characteristic patterns typify each conceptional age (CA) (age in weeks from conception) and allow the experienced reader to predict within +/- 2 weeks the infant's CA. This paper reviews from an historical perspective (beginning with Berger) the dramatic changes the EEG undergoes from early premature birth (CA, 26 weeks) to term (CA, 40 weeks). The important features of normal EEG development are discussed as well as the clinical significance of an apparent arrest or delay of the normal developmental process, the so-called "dysmature" pattern. It is proposed that close attention to the stage of brain maturation in normal and abnormal EEGs might allow more accurate timing of the brain insult in infants with neurological sequelae.

Interburst interval measurements in the EEGs of premature infants with normal neurological outcome.

Interburst intervals (IBIs) are quiescent periods of cerebral activity, which normally occur in the electroencephalograms (EEGs) of premature infants. Although it is generally felt that the duration of these intervals shorten with increasing conceptional age (CA), no systemic studies of IBIs have been done in a large group of normal premature infants with long-term follow-up and using multichannel routine EEGs. In this study, we measured the IBIs, using defined criteria, in 36 premature infants who were normal at 3 years. The IBIs were measured in 104 EEGs, obtained from these infants, using standard recording techniques. Mean and the maximum IBIs were calculated. IBI duration decreased with increasing CA, although this trend was not very prominent when very restrictive criteria for measurement of IBI length were used. Less restrictive criteria for defining an IBI led to trends which are similar to those of previous studies. Various clinical factors, such as mild encephalopathies, small intraventricular/subependymal hemorrhages, mild bronchopulmonary dysplasia, or patent ductus arteriosus did not significantly alter IBI durations. Comparison with other techniques of IBI measurement and recording are discussed. The longest period of continuous activity during a routine recording was also measured and was found to increase with increasing CA.

Serial EEGs in normal and abnormal infants with birth weights less than 1200 grams--a prospective study with long term follow-up.

Serial EEGs were recorded during the postnatal period from 62 infants with birth weights less than or equal to 1200 gms. Neurological examinations were performed in proximity to the EEG and each infant had at least one imaging study of the brain in the immediate postnatal period. All infants were examined at 2-3 years age. Neurological sequelae were seen in all infants with markedly abnormal neonatal EEGs and in the majority of those with persistently moderately abnormal tracings. A particularly unique EEG abnormality consisting of an arrest of maturation of cerebral electrical activity was seen in infants with bronchopulmonary dysplasia who suffered neurological sequelae. A persistently asymmetric EEG background was recorded in infants with hemispheric pathology who were found to have hemisyndromes at long term follow-up. Serial EEGs were better predictors of long term outcome than imaging studies and the neurological examination.

Positive rolandic sharp waves in the EEG of the premature infant.

Ninety-seven EEGs from 30 premature infants found to have multifocal white matter necrosis on ultrasound (US) or autopsy were reviewed retrospectively. Twenty infants had intraparenchymal echodensities on US that developed into cystic lesions, a finding consistent with periventricular leukomalacia; 8 had intraparenchymal hemorrhages; and 2 had white matter necrosis at autopsy. Four of these infants had no intraventricular hemorrhage. Positive sharp waves in the central (rolandic) regions (PRS) were identified in 22 of these 30 infants (73%) and in 0 of 30 age-matched controls (p less than 0.001). The presence of PRS on the EEG of the premature infant has a high correlation with white matter necrosis rather than with intraventricular hemorrhage. In all cases, this EEG pattern was present prior to the development of cavitations when echodensities were present on US.

An overview of pediatric seizure disorders and epileptic syndromes.

Seizures are common in infants and children and must be differentiated from a wide variety of other neurological and nonneurological disorders which include episodic disturbances of behavior. If the diagnosis is clear, then one must decide if the seizure is an isolated event and unlikely to recur (as are many afebrile generalized convulsive seizures in early childhood), a symptom of underlying cerebral pathology, or part of an epileptic syndrome. The latter may be a potentially lethal neurodegenerative disease or a benign epilepsy with excellent outcome. This review will discuss the various aspects of epilepsy in the pediatric age group, emphasize the benign nature of most seizures in children (including many forms of partial, or focal, seizures), and present an overview of the more serious epileptic syndromes. The myoclonic epilepsies will be used as a model to illustrate the wide scope of epileptic phenomena in infants and children.

Positive rolandic sharp waves in the electroencephalograms of premature neonates with intraventricular hemorrhage.

Seventy-eight electroencephalograms (EEGs) recorded from 44 premature infants with documented intraventricular hemorrhage (IVH) were retrospectively reviewed. Positive rolandic sharp waves (PRS) were observed in 13 of 44 (29.5%) patients. Among infants with grades 3 and 4 IVH, the incidence of PRS was 60% (9 of 15). During the period of study, typical PRS appeared in two EEGs of one premature infant who did not suffer an IVH. PRS were usually associated with moderately abnormal EEG backgrounds and with grades 3 and 4 IVH. Beta activity was superimposed on an average of 21.5% of PRS (beta-PRS). Infants with grades 3 and 4 IVH had a higher incidence of beta-PRS than those with smaller hemorrhages. PRS first appeared in early postnatal life, increased in abundance and then eventually disappeared from the records by 3-4 weeks of age. The field of distribution of PRS was centered at the central parasagittal region (Cz) with generous anteroposterior spread into the frontal and parietal vertices (Fz and Pz) and symmetric lateral spread into the rolandic areas (C3 and C4). Asymmetric involvement of PRS at C3 and C4 may signify differential hemispheric injury. The majority of infants whose EEGs contained PRS died or suffered serious neurologic sequelae. However, their outcomes were not significantly inferior to those without PRS.

EEG in premature infants with intraventricular hemorrhage.

Seventy-eight EEGs from 44 premature infants with CT- or autopsy-verified intraventricular hemorrhage (IVH) were reviewed retrospectively. The patient's most abnormal EEG was a reliable predictor of outcome, independent of the estimated gestational age, 1- and 5-minute Apgar scores, and IVH grade. Nine of 12 infants who had all normal or mildly abnormal EEGs had favorable outcomes. The nine infants whose worst EEGs were moderately abnormal experienced mixed outcomes, ranging from normal survival to death. All 23 infants with one or more markedly abnormal EEGs suffered unfavorable outcomes. Positive rolandic sharp waves, a highly specific EEG pattern for IVH in premature infants, occurred in only 29.5% of the patients. The degree of EEG abnormality correlated significantly with the patient's mental status, but not with the IVH grade. Subarachnoid hemorrhage, hypoxia-ischemia, and focal parenchymal lesions caused electrographic seizures in 14 patients, 12 of whom died (85.7%). This study suggests that EEG has limited value in the diagnosis of IVH. However, it may play an important role in the neurologic assessment of the premature infant with established IVH by confirming clinically suspected seizures and providing reliable prognostic information.

The incidence of EEG abnormalities and outcome of infants paralyzed with neuromuscular blocking agents.

The EEGs of 40 infants paralyzed with D-tubocurarine or pancuronium during the neonatal period were reviewed retrospectively. The 23 infants who survived were re-examined at 1-3 yr of age. Sixteen infants had normal or mildly abnormal EEGs in the neonatal period; 3 died of nonneurologic causes; the remainder were normal at follow-up. Three of 8 infants with moderately abnormal EEGs in the neonatal period died, 2 had neurologic sequelae at follow-up, and 3 were normal at follow-up. Eleven of 16 infants with markedly abnormal EEGs died, and 5 had neurologic deficits at follow-up. Seizures occurred in 16 infants. Ten (63%) of the 16 died, whereas only 7 (29%) of 24 infants without seizures died (p less than .1). Eight infants had seizures only during paralysis. The EEG was statistically the best predictor of neurologic outcome when compared with the following variables recorded before paralysis: estimated gestational age (EGA), birth weight, Apgar score at 1 and 5 min, lowest PO2 and pH and highest PCO2. This study establishes the value of the EEG in the neurologic assessment of iatrogenically paralyzed newborns in the detection of seizures, and confirms previous studies which showed the value of EEG in predicting outcome.

A characteristic EEG pattern in neonatal herpes simplex encephalitis.

EEGs were obtained on six infants with herpes simplex virus (HSV) encephalitis. The first EEG of four of these infants showed a unique multifocal periodic or quasiperiodic pattern; in one of these, a periodic pattern subsequently replaced the quasiperiodic pattern. A fifth infant developed a quasiperiodic pattern on the eighteenth day. All of these infants died or were left with severe encephalopathy. A sixth infant was diagnosed and therapy initiated on day 2. The periodic pattern did not appear in any of this infant's EEGs, and at age 8 months he showed only a moderate motor delay. A periodic EEG in a young infant with partial motor seizures and CSF lymphocyte pleocytosis is virtually diagnostic of HSV encephalitis.

The prognostic value of the electroencephalogram in premature infants.

A retrospective analysis of 184 EEGs performed during the neonatal period was accomplished on 81 premature infants (gestational age less than or equal to 36 weeks). The neurological outcome of the 64 surviving infants, considered as normal or abnormal with minor or major sequelae, was compared with the neonatal EEGs which were graded as normal, moderately or markedly abnormal. Infants whose serial EEGs were normal during the neonatal period were usually normal at follow up or suffered minor sequelae. All the children who had at least one markedly abnormal EEG suffered some type of neurological sequela or died. EEGs were classified as markedly abnormal if they contained at least one of the following patterns: isoelectric or paroxysmal backgrounds, positive rolandic sharp waves, electrographic seizures, marked interhemispheric voltage asymmetry or asynchrony or excessively slow background with a reduction or absence of the patterns expected at the particular conceptional age. A moderately abnormal EEG was of no significant prognostic value. This study also revealed the value of recording serial EEGs in the neonatal period. In many cases, markedly abnormal EEG patterns were transient and normal records were often obtained prior to the child's release from the nursery.

Clinical and electroencephalographic characteristics of midline parasagittal foci.

We report the clinical and electroencephalographic (EEG) characteristics of 14 patients with midline parasagittal epileptogenic foci. Montages not including the vertex electrodes demonstrated the abnormal activity poorly or not at all. The clinical manifestations were diverse and included tonic-clonic, atypical absence, and partial seizures. In the majority, no cause could be established. The interictal EEG abnormality did not predict the pattern of clinical attack. Half the patients had evidence of structural brain disease. Four patients had no history of seizures.