Hideo Ohkubo

Developmental changes of brainstem auditory evoked potentials (BAEPs) in normal human subjects from infants to young adults

BAEP has been found to be useful for assessment of subcortical maturation. However, the precise maturational changes of the peripheral and central transmission in normal human subjects are still open to controversy. We obtained a total of 200 BAEPs from 165 normal human subjects ranging from infants to young adults. Electrodes were placed at both mastoids and the reference at the vertex. 85 dB SL click stimuli were presented binaurally at a rate of 13/sec and 2,048 responses were summated on line with an averager. Investigation of the maturation of the transmission time indicated that the peripheral auditory apparatus attains functional maturity during the first 2 months of life, whereas the central transmission time shortens up to the age of 5 to 8 years. III-II and V-IV interpeak latencies (IPLs) showed maturational changes similar to those of V-I IPLs, in contrast II-I and IV-III showed little changes. A clear increase of the amplitude of peak V up to 4 years of age and a subsequent decreasing tendency was observed. The V-I IPLs of males were longer than those of females in each age group. Females also displayed larger BAEPs for wave V than males after 2 years of age. These data indicate that it is worthwhile to have separate latency and amplitude norms for males and females from infants to adults for attaching diagnostic significance to BAEP measures.

Evaluation of DNA probe test for rapid diagnosis of Mycoplasma pneumoniae infections

Daisuke Hata, MD, Fumiyuki Kuze, MD, Yasuhiro Mochizuki, MD, Hideo Ohkubo, MD, Shuichi Kanazashi, MD, Shinji Maeda , MD, Nor inaga Miwa, DVM, and Haruki Mikawa, MD From the Department of Pediatrics, Shizuoka General Hospital, and the Shizuoka Prefectural Institute of Public Health and Environmental Science, Shizuoka, Japan; and the Department of Infection and Inflammation, First Clinic of Medicine, Chest Disease Research Institute, and the Department of Pediatrics, Faculty of Medicine, Kyoto University, Kyoto, Japan

Auditory brain stem responses (ABR) in developmentally retarded infants and children

We recorded ABR in 65 infants and children with developmental retardation and analyzed the relationship between the incidence of abnormal findings and the degree of mental retardation, which was confirmed by follow-up observation and formal intelligence tests. There were 3 cases for whom no response could be obtained. In the 21 retardates with specific causes of retardation or complications, peripheral abnormalities were noted in 13 (62%) and central abnormalities in 11 (52%). The 41 cases of idiopathic retardates were divided into three categories according to the degree of mental retardation. Of 15 cases who were ascertained to be normal or borderline retardates, 3 (20%) showed some abnormal findings. Of 13 cases who were proven to be suffering from mild to moderate mental retardation, 5 (38%) showed abnormal findings. Of 13 cases who were confirmed to be suffering from severe to profound mental retardation, 5 (39%) showed central abnormalities. The high incidence of ABR abnormalities in retardates compared to in normal controls suggests that ABR measurement is a useful tool for evaluating infants who have possible developmental delay. It seems that disturbance of acoustic information processing can disturb language acquisition, and such a consideration is necessary for the education of children who show significant elevation of the response threshold.

Peripheral neuropathy in children on long-term phenytoin therapy

Nerve conduction studies of the ulnar, median, posterior tibial, peroneal and sural nerves were performed in 21 epileptic children aged 6 to 17 years on long-term phenytoin therapy. Auditory brain stem evoked responses were obtained in 16 patients to evaluate the effect of phenytoin on central nervous system synapses. Of the 21 patients examined, 15 (71.4%) showed abnormal findings. The most frequent abnormality was slowed motor conduction velocity of the ulnar nerve (33.3%) and posterior tibial nerve (23.8%), followed by slowed sensory conduction velocity of the sural nerve (20%), lowered H/M ratio (14.3%), slowed motor conduction velocity of the peroneal nerve (14.3%) and of the median nerve (14.2%). A significant correlation was noted between the total dosage and duration of therapy with PHT and the reduction of motor conduction velocity in the posterior tibial nerve. Auditory brain stem evoked responses showed no significant differences in each peak latency between the patients and the normal control group. The study indicates that long-term phenytoin therapy can cause latent impairment of peripheral nerve function in children with no clinical evidence of peripheral neuropathy.

Meningitis due to Actinomyces israelii in an infant successfully treated with ampicillin

Meningitis due to Actinomyces israelii developed in a 31-day-old infant. Early recognition of the meningitis and ampicillin therapy resulted in rapid sterilization of the CSF and remarkable recovery. Infection of the umbilicus was suspected to be the primary focus of this unusual infection. In the world literature, this is the first reported case of actinomycotic meningitis in an infant cured with no sequelae.