Longitudinal EEG, Seizure, and Developmental Patterns in Children With CDKL5 Deficiency Disorder in the First 2 Years of Life

BACKGROUND AND OBJECTIVES: ) deficiency disorder (CDD), it has been observed clinically that EEGs are initially only mildly abnormal and worsen in the first 2 years of life. This study aimed to identify specific EEG patterns, ictal and interictal, in individuals with CDD during the first 2 years of life and to explore their relationship with clinical and developmental outcomes. METHODS: Centers of Excellence, in whom 152 longitudinal clinical EEGs were rigorously analyzed. The retrospectively analyzed data consisted of EEG background, interictal, and ictal parameters, scoring according to the Burden of AmplitudeS and Epileptiform Discharges (BASED) scale, as well as clinical seizure-related features, demographic details, and scores of a CDD-specific developmental scale. RESULTS: = 0.008). DISCUSSION: In CDD, EEG background severity, burden of interictal epileptiform activities, and parieto-occipital paroxysmal fast activity may be associated with developmental and clinical severity. Parieto-occipital paroxysmal fast activity and sequential seizures, while not specific to CDD, are highly suggestive of it.