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Biomedical subjects

P Kellaway

Publications and source records attributed to P Kellaway.

At least 19 recordsLinked to original sources
PubMed1988

Prospective study of outcome of infants with infantile spasms treated during controlled studies of ACTH and prednisone.

We report the long-term outcome of 64 infants with infantile spasms, followed prospectively, using controlled treatment schedules and objective techniques (24-hour EEG and video monitoring) to determine response. Average age at follow-up was 50 months. Of the 64 infants, three (5%) died; of the others, 41 (67%) had developmental retardation of 50% or more or an IQ of 50 or less. Eight patients (13%) composed our cryptogenic study group and were so classified on the basis of normal CT scan, normal development prior to onset of infantile spasms, and undetermined cause. These patients had the better outcome; 38% had normal development or were only mildly retarded. Both the responders and nonresponders in our symptomatic group had a poor outcome; only 5% had normal development or mild impairment. Outcome was not significantly influenced by short versus long treatment lag or by response to therapy. Other types of seizures occurred in 34 patients (53%). In summary, the overall prognosis for long-term outcome in these 64 patients with infantile spasms was poor.

Adrenocorticotropic Hormone↗
PubMed1987

Characterization and classification of neonatal seizures.

To characterize and classify neonatal seizures, we studied 349 neonates, using a portable, cribside EEG/polygraphic/video monitoring system. We recorded 415 clinical seizures in 71 infants; 11 other infants had electrical seizure activity without clinical accompaniments. Each seizure was analyzed in terms of its clinical character and its relationship to the presence of EEG seizure activity. Focal clonic seizures, some forms of myoclonic seizures, and focal tonic seizures were consistently associated with electrical seizure activity. Most "subtle" seizures, all generalized tonic seizures, and some forms of myoclonic seizures were either not associated with EEG seizure activity or had an inconsistent relationship with such activity. Seizures that were consistently and coherently related to focal EEG seizure activity had a high correlation with focal brain lesions and a favorable short-term outcome. Seizures with no relationship or an inconsistent relationship to EEG seizure activity were correlated with diffuse processes such as hypoxic-ischemic encephalopathy and a poor short-term outcome. The clinical and background EEG features of infants whose seizures were not accompanied by EEG seizure activity suggest that these seizures may not be epileptic in character.

Brain↗
PubMed1986

Changes in epileptic spike configuration associated with attainment of seizure control.

This study provides preliminary evidence that computer-derived parameters of interictal spike waveforms can be used to assess seizure hazard in a quantitative manner. Thirteen children with spike foci and simple or complex partial seizures were studied before and during treatment with carbamazepine or phenobarbital; spike parameters were determined from 5- to 30-minute electroencephalographic samples obtained during non-rapid eye movement sleep. Measurements included spike amplitude, duration, and sharpness, and a mathematical combination of these three parameters (the composite spike parameter). Achievement of seizure control was associated with a decrease in spike amplitude, duration, and composite spike parameter, and an increase in normalized sharpness, compared to baseline values. These results suggest that this method may provide a prospective means for estimating drug efficacy that can be applied shortly after attainment of steady-state serum drug levels.

Adolescent↗
PubMed1985

Sleep and epilepsy.

Epileptic mechanisms in the brain are subject to long-duration, time-ordered neuromodulatory processes controlled by endogenous oscillators which are responsible for appropriately phased modulation of various normal physiological processes, including the 24-h sleep/wakefulness cycle and the ultradian 100-min cycle of rapid eye movement/non-rapid eye movement sleep. Both focal and generalized types of epileptiform activity in humans are subject to biorhythmic modulation, and the various modulation patterns observed are in accord with a model which explains these patterns as a consequence of the interaction of two endogenous modulatory processes: one with a period of about 24 h, the other with a period of about 100 min. Differences in the phase angle between the two cyclic processes, determined by time of sleep onset, explain the various modulatory patterns observed. The mechanisms involved in the genesis and elaboration of electrical epileptiform activity in animal models are examined in relation to known processes involved in the physiology of sleep, and compared with data derived from long-term studies of the time distribution of epileptic events in humans. In infantile spasms, clinical seizure activity and the ictal and interictal EEG patterns in relationship to the phases of the sleep cycle, the significant defects in the quality and quantity of sleep in this disorder, and the changes that take place in all of these when seizures are abolished by effective treatment, suggest that pontine mechanisms responsible for the sleep cycle may be involved in the elaboration of infantile spasms and hypsarrhythmia.

Action Potentials↗
PubMed1985

Childhood seizures.

Comprehensive video/EEG/polygraphic monitoring over prolonged periods affords a precise diagnosis of epilepsy and the differentiation between true epileptic events and other abnormal and normal behaviors of infants and children which may be thought to be epileptic. In conjunction with serial monitoring of serum anticonvulsant drug levels, comprehensive monitoring also provides an objective data base for the rational treatment and management of seizure disorders which heretofore have been based on empirical trial and error. Comprehensive monitoring over prolonged periods improves diagnosis and management because it (1) increases the detection of specific electrical epileptiform events, (2) makes possible the precise characterization of the clinical and electrical seizure activities and their interrelationships, and (3) provides a method for the quantitation of the epileptic process in the brain before and after treatment.

Adolescent↗
PubMed1985

Monitoring at the Baylor College of Medicine, Houston.

Three types of systems for comprehensive EEG/polygraphic/video recording are described in detail. These 3 systems, in daily operation in the teaching hospitals of Baylor College of Medicine, were designed to meet the specific needs of research and routine clinical studies of the neonate, the infant, and the young child, respectively. The design rationale, application and operation of these systems are outlined.

Adolescent↗
PubMed1984

Hypsarrhythmia: variations on the theme.

Prolonged monitoring studies of patients with infantile spasms have shown that hypsarrhythmia is a highly variable and dynamic electroencephalographic pattern. Variations of the prototypic pattern (modified hypsarrhythmia) include hypsarrhythmia with increased interhemispheric synchronization, asymmetrical hypsarrhythmia, hypsarrhythmia with a consistent focus of abnormal discharge, hypsarrhythmia with episodes of attenuation, and hypsarrhythmia comprising primarily high-voltage slow activity with little sharp-wave or spike activity. Marked changes in the hypsarrhythmic pattern usually occur during sleep, chiefly during rapid eye movement sleep, when there is a marked reduction in, or total disappearance of, the hypsarrhythmic pattern. Relative normalization of the hypsarrhythmic pattern can also be seen immediately on arousal and during clusters of infantile spasms. Thus, the specific EEG features seen in a given patient depend on multiple factors, including the duration of the EEG recording, the clinical state of the patient, and the presence of various structural abnormalities of the brain.

Arousal↗
PubMed1984

Cerebral concussion in children: assessment of injury by electroencephalography.

An examination was made of 967 initial and follow-up electroencephalograms of 371 children with clinically diagnosed cerebral concussion to determine whether the EEG could provide an objective measure of injury. For each patient, the degree and distribution of EEG abnormalities, as well as their rate of resolution, were correlated with the severity of clinically assessed injury. A close relationship was found between the severity of both initial and longitudinal EEG disturbances and the clinically suspected grade of concussion. Serial EEGs of individual patients showed a similar relationship between time elapsed since injury and degree of abnormality. The rate at which the sequence of EEG resolution took place varied in direct relation to the severity of concussion. It was concluded that the initial EEG and the rate and degree of resolution of EEG abnormalities, together with the time elapsed since injury, can provide objective and reliable information to the clinician for the establishment of the diagnosis and assessment of severity of cerebral concussion in children.

Adolescent↗
PubMed1983

Double-blind study of ACTH vs prednisone therapy in infantile spasms.

Twenty-four patients with infantile spasms were entered in a double-blind, placebo-controlled, crossover study to compare the therapeutic effectiveness of ACTH (20 to 30 units/day) with that of prednisone (2 mg/kg/day). Response to therapy was determined by utilizing a comprehensive monitoring system and was defined as a complete cessation of spasms and disappearance of the hypsarrhythmic EEG pattern. A major difference between the effectiveness of ACTH and that of prednisone in stopping the spasms and improving the EEG pattern was not demonstrated. Nine patients responded to ACTH (five initial drug, four crossover), and seven patients responded to prednisone (four initial drug, three crossover). Twelve responded within two weeks of initiation of therapy, and four within six weeks. Therapy was tapered and discontinued immediately after a response was obtained. Five patients had a relapse; four responded rapidly to a second course of therapy. Of the eight patients who failed to respond to hormonal therapy, seven were given clonazepam with no improvement.

Adrenocorticotropic Hormone↗
PubMed1981

Epilepsy: a heuristic model for relating nocturnal sleep EEG spike distributions to the risk of seizure.

The cumulative temporal distribution of epileptiform events in the sleep EEG of epileptic patients is represented by a second-degree regression equation as a basis for summarizing properties of the spike distribution. This heuristic regression model attempts to provide a quantitative as well as an intuitive physical basis for understanding the relationship between epileptiform events and the state of the epileptic patient. The mathematical model is derived in this paper and the regression parameters associated with the model are interpreted. Computer implementation of the epileptiform event detection and the regression analysis have been carried out and typical results obtained from all-night EEG recordings are described.

Computers↗