Kimiko Hara

Behavioral state cycles, background EEGs and prognosis of newborns with perinatal hypoxia

The classification of the background EEG was performed in 132 fullterm neonates who had suffered perinatal hypoxia by visual inspection of whole polygraphic records of 2--3 h duration, i.e., maximally depressed, markedly depressed, moderately depressed, mildly depressed, minimally depressed, normal and other, according to the distribution of 7 EEG patterns. The quantitative analysis of the polygraphic record was made in 33 of the above and 10 control infants to investigate the effect of perinatal hypoxia on the background EEG and behavioral state cycle and to confirm the validity of the above classification. The calssification of the background EEG was well correlated with the disturbance of sleep cycle, which was also related to the interval after the hypoxic insult. The relation between sleep states and EEG patterns also had a close correlation with the classification and became progressively disrupted with increasing severity of the background EEG. Each grade of the background EEG abnormality had a different prognostic significance accordsing to the time of the recording. The one in the first week offered the best prognostic value.

Long‐term Prognosis after Infantile Spasms: a Statistical Study of Prognostic Factors in 200 Cases

A follow‐up study was made on 200 children (115 boys, 85 girls) who had had infantile spasms, in order to compare their present condition over the age of six years with various prognostic factors. 48 of the children (30 males and 18 females) had died, and all the rest were aged six years or older at the time of final follow‐up. 139 of the children had received ACTH therapy: at final follow‐up, spasms had ceased in 43.5 per cent, and about the same proportion showed normal physical development; 23 per cent had normal mental development and 15.4 per cent were attending ordinary schools. Complete recovery (normal mental and physical development and attending ordinary schools) was achieved in only 19 cases (9.5 per cent). Of the cryptogenic cases, 44.4 per cent had made a full recovery.

Infantile spasms: Etiological factors, clinical aspects, and long term prognosis in 200 cases

The etiological factors, clinical aspects and long term prognosis were studied in 200 patients with infantile spasms. Forty-eight (24.0%) died and the rest were aged 6 years or more at the time of final follow-up. In 73 (36.5%) the etiology was prenatal, in 44 (22.0%) perinatal, and in 17 (8.5%) postnatal: 18 cases (9.0%) were cryptogenic. The remaining 48 (24.0%) patients were doubtful cases. The mortality of the pre-and perinatal cases at 35.6% and 34.1% respectively was significantly higher than that in the other etiologic groups (P<0.001).With regard to the onset of spasms, these were very carly in the pre-and perinatal groups, whereas in the postnatal group the onset was late. The onset in the doubtful and cryptogenic groups was in between. Some 44.4% of the cryptogenic cases showed normal mental and physical development after the age of 6 years, whereas less than 10% of the prenatal and perinatal group did so. Almost all of the doubtful cases became mentally subnormal.The incidence of a family history of epilepsy or other convulsive disorders in the first, second and third degree relatives was highest in the cryptogenic cases (40.0%), and lowest in the perinatal cases (9.3%) (P<0.01). The incidence of laughing attacks was highest in the postnatal cases (42.9%), against no such attacks in cryptogenic cases (P<0.01). The attacks seemed to be linked with organic brain lesions. Among various factors related to the etiology of infantile spasms, genetic propensity seemed especially important in cryptogenic cases.

The evolution of EEG features in infantile spasms: a prospective study.

SUMMARY

Maturation of visual evoked responses in low-birthweight infants

Visual evoked responses (vers) were studied in a total of 104 polygraphic eeg recordings of 11 small‐for‐dates and 15 pre‐term infants, with the following results.

The evolution of visual and auditory evoked potentials in infants with perinatal disorder

The evolutionary changes of evoked potentials (EPs) were studied from the neonatal period up to 1 year of age in 41 infants with various perinatal disorders. Abnormal EPs in the first week of life recovered quickly. In infants with normal outcome, abnormal EPs became normal within a month. In infants with cerebral palsy (CP) or mental retardation (MR), EPs recovered within 2-3 months of age. Infants with more severe neurological damage showed abnormal EPs even beyond 6 months of age. Abnormal EPs beyond 2 weeks of age indicated poor prognosis. As for the wave form of EPs, absent responses or abnormal wave form reflected more severe brain dysfunction. AEPs tended to show more profound abnormalities than VEP. However, some infants with absent AEP in the first week of life had a favorable prognosis. AEPs seemed to be more easily affected by brain dysfunction.

The evolution of electroencephalographic features in lissencephaly syndrome

The electroencephalographic features and their evolutional changes with age were described in three cases of lissencephaly syndrome diagnosed by CT scan. The case with more severe lissencephaly displayed very similar EEG findings. In early or middle infancy when infantile spasms began, EEG showed very high amplitude (more than 400 microV) slow waves mixed with sharp theta-waves. In their clinical course, they showed extreme spindles and in late infancy, the EEG revealed a tendency towards bilaterally synchronous discharges of high amplitude sharp and slow waves. On the other hand, milder forms of lissencephaly showed hypsarrhythmia in early infancy. In the late infancy the EEG showed bisynchronous sharp and slow waves of more than 200 microV. The anomaly ranging from agyria to pachygyria seems to be closely associated with varying EEG abnormalities from extremely high voltage hypsarrhythmia to focal spikes. The very high voltage of hypsarrhythmic patterns and the very low frequency of sharp wave discharges seem to be typical in the most severe lissencephaly or agyria

Neonatal seizures and subsequent epilepsy

Neonatal findings and evolutionary courses of epileptic seizures were described in newborns who had seizures during the neonatal period and later developed epilepsy. Neonates with CNS dysgenesis ran the highest risk (80%) for subsequent epilepsy. About 30% of those who suffered from perinatal hypoxia and/or intracranial birth injury and 30% of those who had meningitis developed subsequent epilepsy. In perinatal brain injury, those who developed epilepsy showed more abnormal neurological and electroencephalographic findings than those who did not. The more abnormal the neonatal background EEG, the more frequently epileptic fits developed later. There was no such relationship in CNS dysgenesis. Myoclonic seizures were associated with the most severe brain damage. Newborns who later displayed West syndrome had also very abnormal neonatal EEG whereas those who manifested other types of fits more often had less abnormal neonatal EEGs. In West syndrome, hypsarrhythmia was preceded by focal or multifocal spikes, and closely temporally related with the onset of spasms, but there was a variety of intervals between the onset of clinical fits and EEG spikes in generalized or focal motor seizures.

Development of the motor behavior during sleep in newborn infants

Body movements during sleep were examined in eight non-eventful preterm babies and two full-term babies using the polygraphic methods including superficial EMG. Typical movements in quiet sleep were startle (St) or generalized phasic movement (GPM) and increased tonic activity in chin muscles. In active sleep, instead of total simultaneous patterns observed in quiet sleep, more un-coordinated and localized movements such as generalized movement (GM), localized tonic movement (LTM), localized phasic movement (LPM) and clonic movement (CM) occurred. Longitudinal study of movements revealed a decrease of St or GPM, GM and LPM. LTM did not decrease with increasing conceptional age. The differences of decreasing tendency among these movements may indicate the differences of maturational changes in the different part of CNS.

Heart Rate Variability during Sleep and Wakefulness in Low-Birthweight Infants

The effects of various stages of sleep and wakefulness on heart rate were studied, with R-R interval histograms computed by a ATAC computer, in serial polygraphic EEG recordings made on 22 low-birthweight infants. The heart rate depended on postnatal age rather than on conceptional age, decreasing progressively after birth to each a minimum at various days between 7 and 30 days old, followed by a gradual increase. The heart rate was higher during stage 3 than during stage REM. The heart rate variability was greatest during stage REM and stage 1; it was smallest during stage 3. During crying and bottle feeding, the variability was as small as during stage 3. The variability during wakefulness was larger than during stage 3, but far smaller than during stage REM. The heart rate was very regular, and without the changes associated with sleep stages in infants of 25 to 30 weeks’ conceptional age.