Susumu Hakamada

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.

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

Doxapram in the treatment of idiopathic apnea of prematurity: desirable dosage and serum concentrations

Since the introduction of aminophylline for the treatment of idiopathic apnea of prematurity, successful treatment has been documented, j,2 but more aggressive measures such as continuous positive airway pressure or mechanical ventilation may be required. Doxapram, an analeptic agent with a wide safety margin, is an effective respiratory stimulant in adults, 3 and has been used to overcome idiopathic apnea of prematurity. 4 Recently, the efficacy and safety of doxapram in premature neonates with severe idiopathic apnea resistant to treatment with aminophylline have been documented? 4 Our purpose was to determine the appropriate dosage of doxapram by measuring its serum concentrations.

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.

Hydranencephaly: sleep and movement characteristics.

Sleep and body movements were studied in 2 hydranencephalic neonates using visual analysis and polygraphic recording. They manifested periodic alternation of active and quiet sleep with peculiar movements of bilateral synchronized patterns. Generalized phasic movements were significantly increased and localized tonic movements were reduced. In view of the complete absence of cerebral hemisphere in this disorder, the movement of bilaterally synchronized pattern or increase of generalized phasic movement are considered to be generated from the basal ganglia and/or brain stem without cerebral hemisphere, whereas, localized tonic movements have more cortical correlation in its organization. The observation of body movements may be useful in detecting hydranencephaly in early infancy.

The Role of Perinatal Brain Injury in the Genesis of Childhood Epilepsy

In order to elucidate the significance of perinatal brain damage in the etiology of epilepsy, 139 full‐term neonates considered to have suffered a severe degree of perinatal hypoxia were examined neurologically and electroencephalographically for two‐nine years. Thirty‐eight (27.3%) of them developed epileptic seizures during the follow‐up period. Sixteen infants developed infantile spasms at ages two‐13 months, while 10 manifested generalized motor seizures mainly at one‐four years. They all had neonatal background EEGs suggesting a severe degree of brain damage, although the infants with infantile spasms and myoclonic seizures showed more abnormal neonatal EEGs than those with other types of fits.

Neurophysiological and neuroradiological features preceding infantile spasms

Neonatal EEG, cerebral evoked potentials, CT scan findings and their evolution were investigated in 42 neonates who eventually developed the West syndrome. In infants with perinatal hypoxia, the EEG displayed most often marked or maximal depression in the first week of life. The highly abnormal initial EEG improved progressively with time. The most frequent findings in early infancy was discontinuous tracing and persistent alternating tracing at 1-2 months, and absent sigma rhythms at 3-4 months. The VEP, AEP and CT scan also showed findings suggesting severe degree of brain damage. In infants with meningitis, the initial EEG was less depressed but the EEG abnormality persisted or worsened. In infants with prenatal causes the neonatal EEG was variable, ranging from a normal background EEG to specific abnormalities. The evolution of paroxysmal abnormalities was similar in all groups. There were no epileptiform discharges in early months. The appearance of hypsarrhythmia was preceded by focal and then multifocal spike or sharp wave discharges.

Apparent brain atrophy and subdural hematoma following ACTH therapy

A case of subdural hematoma following ACTH-Z therapy for infantile spasms was presented. A female baby of 5 months old showed little clinical evidence of cerebral dysfunction associated with subdural hematoma. There have been several reports about the relationship between steroid treatment and apparent brain atrophy on the CT brain scans. Then, we studied the CT brain scans before and after ACTH-Z therapy for infantile spasms, atonic seizure or Lennox syndrome and showed some relationship between apparent brain atrophy on the CT brain scans and ACTH-Z treatment. We also discussed the possible etiology of apparent brain atrophy and subdural hematoma, and stressed the necessity of extreme caution with long-term ACTH-Z administration.

Development of the monosynaptic reflex pathway in the human spinal cord

Development of the monosynaptic reflex pathway of the spinal cord was investigated in 96 neurologically normal infants with ages ranging from 25 weeks in postconceptional age (PCA) to 24 months after full-term delivery (PDA) by examining H-reflexes from the triceps surae and hypothenar muscles in terms of their incidence, latency and maximal size in reference to the maximal M-wave. The triceps H-reflex was evoked in all cases, and the latency was longest (26 ms) in the youngest case of 25 weeks (PCA). It gradually shortened until full-term gestation, reaching the shortest value of 17 ms (mean). The H-reflex size initially increased until full-term gestation, reaching the maximum value of 70% and then reducing gradually to the plateau level of about 30% at 12 months (PDA). The hypothenar H-reflex could not be elicited until 32 weeks (PCA). The time course of changes in its latency and size was similar to those of the triceps H-reflex, except that it could not be elicited after 12 months (PDA). Thus, the monosynaptic reflex pathway is already functioning at the age of 25 weeks (PCA) in man. The significance of the systematic change in latency and excitability of the H-reflex with age is discussed.