Crucial involvement of fast waves and Delta band in the brain network attributes of infantile epileptic spasms syndrome

Objective

This study aims to describe the characteristics of the brain network attributes in children diagnosed with Infantile Epileptic Spasms Syndrome (IESS) and to determine the influence exerted by adrenocorticotrophic hormone (ACTH) or methylprednisolone (MP) on network attributes.

Methods

In this retrospective cohort study, we recruited 19 infants diagnosed with IESS and 10 healthy subjects as the control from the Pediatric Neurology Department at the Third Affiliated Hospital of Zhengzhou University between October 2019 and December 2020. The first thirty-minute processed electroencephalograms (EEGs) were clipped and filtered into EEG frequency bands (2 s each). A comparative assessment was conducted between the IESS group and the controls as well as the pre- and post-treatment in the IESS group. Mutual information values for each EEG channel were collected and compared including characteristic path length (CPL), node degree (ND), clustering coefficient (CC), and betweenness centrality (BC), based on graph theory.

Results

Comparing the control group, in the IESS group, there was an increase in CPL of the Delta band, and a decrease in ND and CC of the Delta band during the waking period, contrary to those during the sleeping period (P < 0.05), a decreased in CPL of the fast waves and an increase in ND and CC (P < 0.05) in the sleep-wake cycle, and a decrease in ND and CC of the Theta band in the waking phase. Post-treatment compared with the pre-treatment, during the waking ictal phase, there was a noted decrease in CPL in the Delta band and fast waves, while an increase was observed in ND and CC (P < 0.05).

Conclusions

The Delta band and fast waves are crucial components of the network attributes in IESS.

Significance

This investigation provides a precise characterization of the brain network in children afflicted with IESS, and lays the groundwork for predicting the prognosis using graph theory.

Biallelic Variants in CNPY3, Encoding an Endoplasmic Reticulum Chaperone, Cause Early-Onset Epileptic Encephalopathy

Early-onset epileptic encephalopathies, including West syndrome (WS), are a group of neurological disorders characterized by developmental impairments and intractable seizures from early infancy. We have now identified biallelic CNPY3 variants in three individuals with WS; these include compound-heterozygous missense and frameshift variants in a family with two affected siblings (individuals 1 and 2) and a homozygous splicing variant in a consanguineous family (individual 3). All three individuals showed hippocampal malrotation. In individuals 1 and 2, electroencephalography (EEG) revealed characteristic fast waves and diffuse sharp- and slow-wave complexes. The fast waves were clinically associated with seizures. CNPY3 encodes a co-chaperone in the endoplasmic reticulum and regulates the subcellular distribution and responses of multiple Toll-like receptors. The amount of CNPY3 in lymphoblastoid cells derived from individuals 1 and 2 was severely lower than that in control cells. Cnpy3-knockout mice exhibited spastic or dystonic features under resting conditions and hyperactivity and anxiolytic behavior during the open field test. Also, their resting EEG showed enhanced activity in the fast beta frequency band (20-35 Hz), which could mimic the fast waves in individuals 1 and 2. These data suggest that CNPY3 and Cnpy3 perform essential roles in brain function in addition to known Toll-like receptor-dependent immune responses.