Katsuhiko Iwase

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.

Spindle‐like Fast Rhythms in the EEGs of Low‐birthweight Infants

Quantitative analysis made on spindle‐like fast rhythms in the eegs of 39 low‐birthweight infants (28 pre‐term and 11 small‐for‐dates) resulted in four main findings.

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.

Long-Term Prognosis of Convulsive Disorders in the First Year of Life: Mental and Physical Development and Seizure Persistence

Summary: A follow‐up study was made on 304 children (164 boys, 140 girls) with convulsive disorders, excluding occasional convulsions, in the first year of life. All patients except 45 who died were followed until 6 years of age or older. At the final follow‐up, the subjects were divided into six groups according to the degree of mental and physical development (groups I‐VI). Seizures were regarded as absent if the patient had been seizure free for more than 3 years. At the final follow‐up, seizures had ceased in 57.7%, and 43.4% had normal mental and physical development (group I). As to the initial diagnosis, the percentage of group I at the final follow‐up was 81.8% with febrile convulsions and 37.6% with epilepsy. In patients without seizures it was 69.7% with febrile convulsions and 55.8% with epilepsy. Some 80.6% of patients with unclassified generalized motor seizures, 11.5% of those with infantile spasms, 2.9% of those with secondary generalized epilepsy other than infantile spasms, 46.4% of those with partial seizures, and 25.0% of those with hemiconvulsive seizures were finally placed in group I. The percentage of patients without seizures was 81.4, 33.0, 34.4, 57.7, and 100%, respectively. As has been suggested, among the first‐year epilepsies, a subgroup with a more favorable prognosis may exist. Further studies regarding the etiology, ictal EEGs, and effectiveness of treatment and long‐term prognosis of these cryptogenic benign infantile convulsions are needed to provide a firm basis for understanding convulsive disorders in the first year of life.

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.

Visual evoked responses during sleep and wakefulness in pre-term infants

Abstract The effects of two stages of sleep (REM and non-REM sleep) and wakefulness on the visual evoked responses (VERs) were studied in a total of 94 polygraphic EEG recordings obtained repeatedly from 15 pre-term infants. The latencies of various peaks of the VERs did not differ significantly during REM sleep and Stage 3 (characterized by “ trace alternant ”) at all conceptional ages from 29 through 45 weeks. The amplitudes of long latency negative waves at 29–34 weeks conceptional age (N 1 ) and at 35–38 weeks (N 2 ) were significantly greater during REM sleep than during Stage 3. This is in contrast to the findings previously obtained on adults. The latencies were found to be shortest and the amplitudes largest during wakefulness.

Prognostic factors of infantile spasms from the etiological viewpoint

We investigated the prognostic factors for mental and physical development and seizure control by dividing the subjects into various etiologic groups in 200 patients with infantile spasms, all of whom (except 48 who died) were aged six years or older. The results were as follows: 1) Intermediate (4-12 mos) onset was found to be a favorable prognostic factor for seizure control in cryptogenic cases, although there was no relation between the age of onset and prognosis in other etiologic groups. 2) There was a significant correlation between the treatment lag and long-term prognosis for mental and physical development only in cryptogenic cases. A short treatment lag (0-2 mos) was associated with a good prognosis. All cryptogenic patients who had no relapse after ACTH therapy developed normally, although in symptomatic cases, there was no correlation between the relapse and the outcome.

Predictors of Long-Term Outcome of Convulsive Disorders in the First Year of Life: Clinical Usefulness of Five Risk Factors

The clinical usefulness of 5 risk factors (delayed development before the onset of seizures, abnormal EEG, symptomatic etiology, abnormal past histories, nonbrief symmetric generalized tonic and/or clonic convulsions) used to indicate long-term prognosis was investigated in 295 children who had convulsive disorders in the first year of life. All patients were followed up to the age of 6 years or older. Patients without any of these risk factors showed mentally and physically normal development, and 89% became seizure-free. However, only 10% or less of the high-risk group with 3 or more of these factors became mentally and physically normal. The score of these 5 factors was significantly related to the long-term prognosis and was assumed to be a valuable index to prognosis in the early stages.