Osami Okubo

AUDITORY EVENT‐RELATED POTENTIALS AND REACTION TIME IN CHILDREN EVALUATION OF COGNITIVE DEVELOPMENT

The authors studied age‐related correlations of auditory event‐related potentials (ERPs) using the conventional ‘oddball’ paradigm and reaction time in 175 normal subjects, aged between four and 21 years. From four years, the latencies of N100, N200 and P300 in ERP progressively shortened until about 16 to 17 years, after which they reached adult level, but with a slight tendency to prolongation towards 20 years; there was no trend for amplitude changes. The reaction time was more rapid than that of P300 latency. These findings indicate that the cognitive function of children improves rapidly until 16 to 17 years. A reduced difference between P300 latency and reaction time with age implies additional progress in motor skill. Combining P300 latency and reaction‐time studies may provide more detailed information for the evaluation of the development of cognitive function and motor skill.

A study of mismatch negativity in newborns

Abstract 
 Background : Although newborns are presumed to have cognitive ability, studies on the objective cognitive ability of neonates are making little progress.

A case of Guillain‐Barré syndrome accompanied by sympathetic overactivity and hypertensive encephalopathy

Hypertension has often been observed in patients with Guillain‐Barré syndrome, and various underlying mechanisms have been implicated. We report the case of a child with the Guillain‐Barré syndrome whose hypertension was associated with increases in both renin activity and circulating catecholamines. This case also appeared to be complicated by hypertensive encephalopathy. Following administration of intravenous regitine, a blood pressure change was observed and cardiac performance was assessed by two‐dimensional echocardiography. Results indicated that increased total peripheral resistance may have been responsible for the symptoms and the hypertension. The hypertension was effectively managed by nifedipine, captopril and prazosin without the need for β‐blockade.

Facial palsy associated with mumps parotitis.

Peripheral facial nerve paralysis is relatively common in the pediatric age group. However, facial palsy rarely has been documented in patients with mumps parotitis. This case report describes the findings of a 3-year-old Japanese boy who developed facial palsy immediately after mumps parotitis. This work calls attention to a possible association between mumps parotitis and facial palsy.

Magnetic resonance imaging of the cauda equina in two patients with Guillain‐Barré syndrome

The results are presented of magnetic resonance imaging (MRI) of the spine in two cases of childhood Guillain‐Barré syndrome. After injection of gadolinium‐diethylenetriamine pentaacetic acid, MRI showed enhancement of the cauda equina in these patients. These MRI observations may help confirm the diagnosis of Guillain‐Barré syndrome. The nerve root enhancement resolved as the clinical symptoms improved. Serial imaging may be useful in monitoring the response to therapy and assessing new treatment regimens. It may also yield a better understanding of the disease process.

Brain evoked potentials of 3‐D auditory stimuli

Background : For evaluation of spatial cognitive function, we studied the brain evoked potentials (EP) of 3‐D auditory stimuli in regard to the change of latencies in normal subjects aged 1−21 years and compared them with patients who have mental retardation (MR).

Motor-evoked potentials in a child recovering from transverse myelitis

We describe a 13-year-old female, with an inability to walk because of transverse myelitis, who demonstrated progressive recovery of both motor function and motor- evoked potentials (MEP). At 4 weeks after onset, amplitudes of MEP were decreased, latencies were prolonged, and cortical somatosensory-evoked potentials (SEP) were absent. At 6 and 12 weeks, MEP revealed progressively higher amplitudes and shorter latencies. SEP also recovered. MEP and SEP recovery paralleled clinical recovery. MEP in response to transcranial magnetic stimulation may provide guidance regarding recovery from spinal cord disorders in children.

Improvement of intractable childhood epilepsy following acute viral infection

In this study, we report 11 patients with intractable childhood epilepsy that improved following acute viral infection. The patients were 8 boys and 3 girls. Six of the 11 children were diagnosed as West syndrome (5 of the symptomatic type and 1 of the cryptogenic type). The remaining 5 children were myoclonic seizures. The patients became seizure free within 6 days following acute viral infections without an exchange or addition of antiepileptic drugs (AEDs). The types of acute viral infections were Exanthema subitum (Roseola infantum) in 5 patients, Rotavirus gastroenteritis in 2 patients, Measles infection in 2 patients, Herpetic stomatitis in 1 patient and Common cold in the remaining patient. Salaam seizures and/or tonic spasms disappeared within 6 days after the onset of viral infections, and hypsarrhythmia evolved to localized spikes on electroencephalography (EEG) in the patients with West syndrome. Epileptic seizures disappeared rapidly and EEG gradually normalized or improved in patients with myoclonic seizures. Four patients became seizure free for 5 years to 20 years. In 6 patients, seizures relapsed within 14 days to 1 month after the disappearance of seizures. One child remained seizure free for 12 months after viral infection. Common factors in 4 children who were continuously seizure free include (1) normal or almost normal findings of brain CT/MRI, (2) normal development prior to the onset of epileptic seizures, and (3) a short time interval between the onset of seizures and the acute viral infection. We propose several hypotheses including an immunological effect for the improvement of intractable childhood epilepsy following acute viral infection. Further study may provide important information concerning the mechanism of seizure control and the applicable to treatment for intractable childhood epilepsy.

Event-related potentials in response to 3-D auditory stimuli.

To evaluate auditory spatial cognitive function, age correlations for event-related potentials (ERPs) in response to auditory stimuli with a Doppler effect were studied in normal children. A sound with a Doppler effect is perceived as a moving audio image. A total of 99 normal subjects (age range, 4-21 years) were tested. In the task-relevant oddball paradigm, P300 and key-press reaction time were elicited using auditory stimuli (1000 Hz fixed and enlarged tones with a Doppler effect). From the age of 4 years, the P300 latency for the enlarged tone with a Doppler effect shortened more rapidly with age than did the P300 latency for tone-pips, and the latencies for the different conditions became similar towards the late teens. The P300 of auditory stimuli with a Doppler effect may be used to evaluate auditory spatial cognitive function in children.

A MOTHER AND DAUGHTER WITH AGENESIS OF THE CORPUS CALLOSUM

A mother and daughter with agenesis of the corpus callosum are reported. There have only been 11 prior case reports of the familial occurrence of agenesis of the corpus callosum in the absence of extracranial malformations. Most of these reports have described familial occurrence among siblings. The present communication is only the second description of a parent and child with agenesis of the corpus callosum A review of the published cases of familial syndrome unrelated agenesis of the corpus callosum indicates that both mental, developmental and neurologic disorders in cases involving parent and child are milder than those in cases involving siblings. Of additional interest, electroencephalography performed in this patient during sleep, frequently revealed bilateral asynchronous sleep spindles, supporting the hypothesis of previous investigators that the synchronicity of sleep spindles requires intact intercerebral commissures.