Lipocalin-type prostaglandin (PG) D synthase (L-PGDS) catalyzes the isomerization of PGH₂, a common precursor of various prostanoids, to produce PGD₂, a potent endogenous somnogen. L-PGDS is localized in the leptomeninges, choroid plexus, and oligodendrocytes of the central nervous system. PGD₂ is proposed to be a major humoral sleep-inducing factor accumulated in the brain during wakefulness. PGD₂ stimulates DP₁ receptors localized in the basal forebrain and increases the local extracellular concentration of adenosine, which activates A _2A re ceptor-possessingn eurons in the basal forebrain and/or ventrolateral preoptic area (VLPO). The intracerebroventriculari nfusion of PGD₂ or adenosine A_2A re ceptor-agonists induces non-REM sleep and increases the expression of fos protein in VLPO. The activation of VLPO neurons is associated with decreased fos expression in the histaminergic tuberomammillary nucleus (TMN), one of the arousal centers. The GABAergic inhibition of TMN is involved in non-REM sleep induction by PGD₂ or adenosine A_2A receptor-agonists.T he neural network between VLPO and TMN is considered to play a key role in the regulation of vigilance states.

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Since 1999, we have been trying to establish a reliable method for evaluating social functioning ability (SFA) of physically handicapped children, in cooperation with the Project of Comprehensive Study of Disability, Social Health, and Welfare supported by the Ministry of Health, Labor and Welfare, Japan. In this study, we investigated the reliability and accuracy of the 4th edition of “The Evaluation of SFA ”. This evaluation consists of 40 items in 15 areas. We examined 45 disabled patients (26 males and 19 females) aged 12-27 years (mean age, 16 years). The reliability was checked by agreement of evaluations of the same patient carried out by two examiners. The results showed good reliability (κ value of 0.42). According to the results of questionnaires, 97% of the examiners regarded this evaluation to be useful. Although the score of SFA correlated with intelligent quotient/development quotient, the score did not correlate with motor disability level. We hope that this evaluation will be widely used to upgrade SFA of disabled children

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Narcolepsy is characterized by excessive daytime sleepiness (EDS), cataplexy and other abnormal manifestations of REM sleep. Recently, it was discovered that the pathophysiology of idiopathic narcolepsy-cataplexy is linked to orexin ligand deficiency in the brain and cerebrospinal fluid. Orexin neurons localize in the posterior hypothalamic area, which was previously described as “waking center” by von Economo in 1920s. Hypersomnia due to orexin ligand deficiency can also occur during the course of other neurological conditions, such as hypothalamic tumor, encephalopathy and demyelinating disorder (i.e. symptomatic hypersomnia). We experienced 8 pediatric cases with symptomatic hypersomnia. These cases were diagnosed as brain tumor (n=2), head trauma (n=1), encephalopathy (n=1), demyelinating disorder (n=3) and infarction (n=1). Six pediatric cases with orexin measurements from the literatures were additionally included and total 14 cases were studied. Although it is difficult to rule out the comorbidity of idiopathic narcolepsy insome cases, a review of the case histories reveals numerous unquestionable cases of symptomatic hypersomnia. In these cases, the occurrences ofthe hypersomnia run parallel with the rise and fall of the causative diseases. Most of symptomatic hypersomnia cases show both extended nocturnal sleep time and EDS consisting of prolonged sleep episodes of NREM sleep. The features of nocturnal sleep and EDS in symptomatic hypersomnia are more similar to idiopathic hypersomnia than to narcolepsy.

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Several reports raised the possibility that dysfunction of saccadic eye movements produces reading disorder (RD), although opposite conclusions have also been reported. In this study, saccadic eye movements were investigated in 13 forth graders with RD and 20 agematched controls during reading and non-reading tasks. Compared to the control group, children with RD showed significantly higher incidences of both forward and backward saccadic eye movements in reading tasks, while they revealed a significantly lower number of saccadic eye movements in response to sequentially moving targets in two types of non-reading tasks. These problems, seen in non-reading tasks, suggest that excessive saccadic eye movements observed in RD children during reading are not produced by mechanisms involved in the language and phonological processes alone, but also those in the saccadic eye movement process. Dysfunction in the saccadic eye movements could be one of the causal factors that produce RD.

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Clinical and electroencephalographic features of epilepsy and the prognosis of intelligence were investigated in 156 children with hydrocephalus. Of these 53 (34.0%) had epilepsy. The incidence and outcome of epilepsy were determined by the etiology of hydrocephalus. The incidence was high in children with hydrocephalus caused by intra-cranial infection and dysgenetic hydrocephalus without dysraphism. Furthermore, it was difficult to control the epileptic seizures in these patients. In contrast, children with dysgenetic hydrocephalus caused by dysraphism and simple hydrocephalus had lower incidence of epilepsy and epileptic seizures had been well controlled in these cases.
In hydrocephalic children, localization-related epilepsy was the most common. Complex partial seizures and focal motor seizures were frequently observed. Common electroencephalographic findings were focal spikes or multi-focal spikes. The intelligence quotient was significantly lower in children with epilepsy than in those without epilepsy. All these findings suggest that the incidence of epilepsy may be a crucial prognostic factor in children with hydrocephalus.

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An 11-month-old boy with multiple surface anomalies and respiratory distress due to upper airway narrowing developed generalized tonic seizures coinciding with apnea. The ictal electroencephalography showed an abrupt onset of right-sided unilateral rapid activity with increasing amplitude followed by bursts of spike and wave complexes. The seizures were completely controlled with non-intravenous highdose phenobarbital therapy. The serum level of phenobarbital at seizure control was 80 μg/ml. The serum level of phenobarbital peaked as high as 123 μg/ml; the patient developed neither liver function abnormality nor hypotension which necessitated any pressor agents. Although the patient was intubated, spontaneous respiration was intact after seizure control. Extubation, however, failed twice because of diminished cough reflex. After decrease of the phenobarbital dose and the development of drug tolerance, the patient was successfully weaned from respiratory support. High-dose phenobarbital therapy is effective for refractory epilepsy in patients complicated by respiratory distress. Although it was reported that respiratory depression was not severe with high-dose phenobarbital therapy, respiratory status may worsen in such patients due to the diminished cough reflex. Therefore the careful and prolonged management is essential.

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We report two female cases of acute disseminated encephalomyelitis with onset of 19 and 15 months, respectively. MRI demonstrated the T₂-high lesions in the cerebral and cerebellar white matter, and the basal ganglia in addition to the spinal cord in the latter case. Treatment with high dose of intravenous methylprednisolone was effective to ameliorate the symptoms in both cases, although spasticity persists in the leg of the latter case. We review ten Japanese cases of acute disseminated encephalomyelitis with the onset before the age of 24 months, including our cases and eight reported cases in the literatures. And we found no significant interrelationships between age of onset and clinical features.

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Here we report a 12-year-old boy with idiopathic neuralgic amyotrophy who had two episodes of shoulder pain followed by shouldes muscle atrophy and weakness at the age of 7 and 11 years, respectively. These symptoms were self-limited and disappeared within 9 months. During the second episode, electromyograph (EMG) revealed neurogenic changes in the deltoid muscle. Muscle imaging showed the right deltoid muscle atrophy with slightly high intensity areas on T₁ and T₂weighted images in MRI. Muscle biopsy from the right deltoid muscle revealed neurogenic changes with denervating and reinnervating processes.
Neuralgic amyotrophy is characterized by neuralgic pain followed by weakness and atrophy at a unilateral extremity and is usually selflimited. EMG and imaging studies showed focal neurogenic abnormalities, which were confirmed by muscle biopsy. Neuralgic amyotrophy usually occurs in young adults and it is very rare in children.

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[in Japanese]

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[in Japanese]

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