Differences in psychosocial factors and sleep study findings between delayed sleep-wake phase disorder and hypersomnia in teenagers.

Central hypersomnia (HS) and delayed sleep-wake phase disorder (DSWPD) appear commonly in adolescents, and they severely reduce quality of life and have an enormous impact on academic performance and other aspects of development. Although these disorders are thought to be considerably different in etiology, it is sometimes difficult to distinguish them because of their similar clinical features. This study aimed to compare psychosocial factors and sleep study findings between HS and DSWPD in teenagers. The clinical data of 89 teenagers who visited the psychiatric section of the Sleep Medicine Center of Nihon University Itabashi Hospital from January 2013 to December 2019 were analyzed. Psychosocial factors were evaluated at the first visit, and polysomnography (PSG) and the multiple sleep latency test (MSLT) were performed for patients deemed to require definitive diagnosis. Compared with patients with HS, those with DSWPD had a higher rate of mother's employment, introversion, adjustment problems, events that triggered the disorder, concurrent mental disorders, habitual lateness, and difficulty attending school or work. PSG did not show any differences in sleep parameters between the two disorders, except for sleep latency. On the MSLT, sleep latency was shorter in those with HS on the second, third, and fourth tests. The present results suggest that focusing on psychosocial factors could be useful for differential diagnosis of the two disorders that appear commonly in adolescents.

Asymmetrical changes in cerebral blood oxygenation induced by an active standing test in children with postural tachycardia syndrome.

Near-infrared spectroscopy enables recognition of various brain conditions based on certain factors, such as oxygenated hemoglobin (oxy-Hb). Since July 2012, we have been trying to determine the mechanisms of autonomic function in Japanese children with orthostatic intolerance (also called orthostatic dysregulation) in Nihon University Itabashi Hospital in Tokyo, Japan. A total of 23 children aged 7-16 years diagnosed with postural tachycardia syndrome (POTS), a subtype of orthostatic dysregulation, were enrolled in the study. We evaluated the relation between asymmetry in frontal cortex activity and the automatic nervous system and compared oxy-Hb changes in the right and left frontal cortices during an active standing test. We observed that during active standing oxy-Hb decreased in the frontal cortex. The oxy-Hb changes were asymmetrical, with a significantly larger decrease in the left frontal cortex than in the right frontal cortex, suggesting that tachycardia during active standing in POTS patients might be caused by activation of the right frontal cortex, which induces sympathetic nervous system activity.

Cerebrospinal fluid and serum levels of vitamin B6 in status epilepticus children.

Vitamin B6 (B6) is an essential cofactor of glutamate decarboxylase and catalyzes the decarboxylation of the excitatory neurotransmitter glutamate to the inhibitory neurotransmitter gamma-aminobutyric acid (GABA). Although immediate administration of B6 to patients with acute encephalopathy with febrile convulsive status epilepticus (AEFCSE) is effective, it is not known whether prolonged seizures in status epilepticus (SE) children prevent the transport of B6 to the central nervous system (CNS) and/or induce the consumption of B6 inside the CNS. We evaluated the B6 concentration in cerebrospinal fluid (CSF) and serum in SE children. Further, we performed a sequential serum B6 analysis on days 1 and 2 after admission and on the day before discharge. Among the several vitamers of B6, we used pyridoxal (PL) as a representative of B6 in this study. We enrolled 15 SE children (8 boys and 7 girls; age range,1-11years; average age, 3.3years) and 21 control children (3 boys and 18 girls; age range, 7months-14years; average age, 3.0years) and each group was divided into 2 subgroups according to age (4months-1year and 2-14years). We found no significant differences in the CSF PL levels, CSF/serum PL ratios, and serum PL levels in the SE and control subgroups. Our results suggest that prolonged seizures do not result in B6 deficiency in CSF and serum in SE children. Whenever necessary, B6 should be administered to SE children with caution to prevent possible adverse effects.