Increased electroencephalography connectivity precedes epileptic spasm onset in infants with tuberous sclerosis complex

Area of Science:

• Neuroscience
• Pediatric Neurology
• Epilepsy Research

Background:

• Tuberous sclerosis complex (TSC) is a genetic disorder associated with an increased risk of epilepsy.
• Infantile spasms (IS), a severe epilepsy syndrome, often manifest in infants with TSC.
• Early identification of infants at risk for IS is crucial for timely intervention.

Purpose of the Study:

• To investigate whether abnormal electroencephalography (EEG) connectivity patterns are detectable before the clinical onset of epileptic spasms (ES) in infants with TSC.
• To explore EEG connectivity as a potential early biomarker for ES in TSC.

Main Methods:

• Prospective collection of scalp EEG recordings in infants with TSC within their first year of life.
• Comparison of EEG connectivity between infants who developed ES (n=16) and those who did not (n=28).
• Analysis of EEG data in canonical frequency bands using mutual information to derive graph theory measures (global efficiency, characteristic path length, clustering coefficient, modularity).

Main Results:

• Infants who later developed ES exhibited significantly increased EEG connectivity during sleep compared to controls.
• Higher mutual information values, global efficiency, and clustering coefficients, along with shorter characteristic path lengths and lower modularity, were observed in infants who developed ES.
• These findings indicate increased local and long-range neural connectivity with reduced network segregation preceding ES onset.

Conclusions:

• Increased neural connectivity, as measured by EEG, appears to precede the clinical manifestation of ES in infants with TSC.
• This 'overconnectivity' may represent a progressive network synchronization leading to generalized ES.
• Further research is warranted to validate EEG connectivity as a biomarker for ES risk and treatment response in pre-symptomatic infants with TSC.