Sleep state-dependent development of resting state functional connectivity during the preterm period.

STUDY OBJECTIVES: The brains of preterm infants exhibit altered functional connectivity (FC) networks, but the potential variation in sleep states and the impact of breathing patterns on FC networks are unclear. This study explores the evolution of resting-state FC from preterm to term, focusing on breathing patterns and distinguishing between active sleep and quiet sleep. METHODS: We recruited 63 preterm infants and 44 healthy-term infants and performed simultaneous electroencephalography and functional near-infrared spectroscopy. FC was calculated using oxy- and deoxyhemoglobin signals across eight channels. First, FC was compared between periodic breathing (PB) and non-PB segments. Then sleep state-dependent FC development was explored. FC was compared between active sleep and quiet sleep segments and between preterm infants at term and term-born infants in each sleep state. Finally, associations between FC at term, clinical characteristics, and neurodevelopmental outcomes in late infancy were assessed in preterm infants. RESULTS: In total, 148 records from preterm infants and 44 from term-born infants were analyzed. PB inflated FC values. After excluding PB segments, FC was found to be elevated during active sleep compared to quiet sleep, particularly in connections involving occipital regions. Preterm infants had significantly higher FC in both sleep states compared to term-born infants. Furthermore, stronger FC in specific connections during active sleep at term was associated with unfavorable neurodevelopment in preterm infants. CONCLUSIONS: Sleep states play a critical role in FC development and preterm infants show observable changes in FC.

Color density spectral array findings on continuous EEG during therapeutic hypothermia in children with acute encephalopathy.

BACKGROUND: Quantitative EEG is frequently used to monitor children affected by acute encephalopathy (AE), with the expectation of providing comprehensive insights into continuous EEG monitoring. However, the potential of quantitative EEG for estimating outcomes in this context remains unclear. We sought reliable prognostic markers within the color density spectral array (CDSA) of the continuous EEG for AE-affected children undergoing therapeutic hypothermia (TH). METHODS: This retrospective study analyzed CDSA data from eight scalp electrodes of 15 AE-affected children undergoing TH. Two CDSA features were investigated-high-frequency lines (HFLs) and periodic elevation in the low frequency band (PLFB)-along with the corresponding EEG characteristics. The inter-rater reliability for CDSA was assessed by four pediatric neurologists. Outcomes were grouped into either no/mild or severe decline in motor and cognitive functions, then compared with CDSA features. RESULTS: The median EEG recording time was 114 (81-151) h per child. While at least 41 % of HFLs corresponded to typical sleep spindles, 94 % of PLFB aligned with cyclic changes in the amplitude of delta/theta waves on the raw EEG. Inter-rater reliability was higher for HFLs than for PLFB (kappa values: 0.69 vs. 0.46). HFLs were significantly more prevalent in children with no/mild decline than in children with severe decline (p = 0.017), whereas PLFB did not differ significantly (p = 0.33). CONCLUSIONS: This study provides preliminary evidence that reduced HFLs on CDSA predict unfavorable outcomes in AE-affected children undergoing TH. This suggests that maintaining high-frequency waves is critical for optimal brain function.

Underlying Disorders in Children With Infection-Related Acute Encephalopathy.

BACKGROUND: Various factors contribute to the development of infection-related acute encephalopathy (AE) in children, such as infectious agents and chronic underlying disorders. We studied underlying disorders in children with AE to identify predisposing factors of AE. METHODS: We investigated underlying disorders or past histories in patients with two types of AE from the database in the Tokai area of Japan between 2009 and 2022: 204 patients with AE with reduced subcortical diffusion (AED) and 137 with clinically mild encephalopathy with a reversible splenial lesion (MERS). We compared them with 89 patients with acute disseminated encephalomyelitis (ADEM) to clarify the specific disorders in the two AE types. RESULTS: The prevalence of underlying disorders in AED (34%, 70 patients) was significantly higher than that in ADEM (12%, 11 patients) (P < 0.01). The prevalence of underlying disorders in MERS was 23% (32 patients). The underlying disorders included seizure disorders, premature birth, genetic/congenital disorders, and endocrine/renal diseases. In patients with seizure disorders in AED, five patients (18%) had Dravet syndrome and four (15%) had West syndrome, whereas none with MERS had these syndromes. Twenty-five (12%) of 204 patients with AED, three (2%) with MERS, and one (1%) with ADEM were preterm or low birth weight. CONCLUSIONS: The high prevalence of seizure disorders suggests that seizure susceptibility is an important predisposing factor in AED. Premature birth also has an impact on the development of AED. Caution is required regarding the development of AE in patients with chronic seizure disorders or premature birth.

Two Cases of Juvenile Myelomonocytic Leukemia and Myelin Oligodendrocyte Glycoprotein Antibody-Associated Disease.

BACKGROUND: Myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease (MOGAD) is an autoimmune demyelinating disorder that often manifests after infections or vaccinations. We report two patients who developed MOGAD out of eight patients with juvenile myelomonocytic leukemia (JMML) that has never been reported. METHODS: We investigated two patients with JMML who developed MOGAD among 127 patients with leukemia from 2012 to 2021. RESULTS: Patient 1 was treated for JMML and developed fever and impaired consciousness at two years and one month of age. Magnetic resonance imaging revealed high-intensity lesions in the left frontal and left occipital white matter. The serum anti-MOG antibody test was positive, while the test was negative in the stored serum 45 days before the onset of encephalopathy. He had relapse of MOGAD after steroid therapy and plasmapheresis. Patient 2, who was treated for JMML, became apathetic and mute at three years and seven months of age. Magnetic resonance imaging revealed left frontoparietal subcortical high-intensity lesions. Anti-MOG antibody at the onset of encephalopathy was positive, while it was negative in stored serum 57 days before and 47 days after the onset. CONCLUSION: We treated two patients who developed MOGAD out of eight patients with JMML and none with MOGAD out of 119 patients with acute lymphocytic leukemia, acute myelocytic leukemia, or chronic myelocytic leukemia. The activated autoimmune process via the RAS pathway abnormality may have led to the formation of the anti-MOG antibody and the onset of MOGAD. MOGAD can occur in children with JMML, and abnormalities of the RAS pathway possibly contribute to its onset.

Transient cortical diffusion restriction in children immediately after prolonged febrile seizures.

AIM: Little is known about acute febrile status epilepticus-induced injury of extrahippocampal structures. To clarify the presence and clinical significance of acute extrahippocampal injuries, we performed diffusion-weighted imaging (DWI) in children immediately after prolonged febrile seizure (PFS). METHOD: We performed a retrospective cohort study in children younger than 6 years old who visited one of two hospitals due to PFSs between January 2013 and October 2018. PFS was defined as a febrile seizure that persisted for 15 min or longer. We collected brain DWI data within 6 h of the end of PFS. When the initial DWI detected an abnormality, a follow-up DWI was performed a few days later. RESULTS: The study population consisted of 101 patients with PFSs. DWI was performed within 6 h in 51 patients, while the remaining 50 patients did not undergo imaging because of good recovery of consciousness. Restricted cortical diffusion was evident in 9 (18%) patients on initial DWI. All of them underwent DWI within 100 min after PFS. Restricted cortical diffusion was associated with male sex, asymmetrical PFS symptoms, and a shorter duration between the end of the seizure and DWI, but was not associated with seizure duration. All cortical abnormalities had resolved on follow-up DWI of these patients within 72 h after the initial imaging, but ipsilateral hippocampal hyperintensity appeared in one patient. All 9 patients with restricted cortical diffusion were finally diagnosed with PFS and discharged without sequelae. CONCLUSIONS: Some children with PFSs exhibit transient restricted diffusion in the regional cortex on DWI performed immediately after the end of PFS. These transient diffusion changes were not associated with unfavorable epileptic sequelae or neuroimaging in the short-term.