Nonseizure consequences of Dravet syndrome, KCNQ2-DEE, KCNB1-DEE, Lennox–Gastaut syndrome, ESES: A functional framework

Developmental epilepsies and encephalopathies (DEEs) are characterized by many severe developmental impairments, which are not well-described. A functional framework could facilitate understanding of their nature and severity and guide the selection instruments to measure improvements in therapeutic trials. An online survey administered through several parent-organized foundations utilized accepted functional classifications and questionnaires derived from common instruments to determine levels of mobility, fine motor, communication, and feeding functions. Statistical analyses focused on overall levels of function and across-group comparisons adjusted for age. From 6/2018 to 2/2020, 252 parents provided information for one or more functional domains. Median age was 7.2 years (interquartile range (IQR): 3.9 to 11.8), and 128 (51%) were females. DEE groups were Dravet syndrome (N = 72), KCNQ2-DEE (N = 80), KCNB1-DEE, (N = 33), Lennox–Gastaut syndrome (LGS; N = 26), electrographic status epilepticus in sleep (ESES; N = 15), and others (N = 26). Overall, functional hand grasp was absent in 48 (20%). Of children ≥2 years old, 60/214 (28%) could not walk independently, 85 (40%) were dependent on someone else for feeding, and 153 (73%) did not effectively communicate with unfamiliar people. Impairments entailing absence or near absence of independent function (profound impairment) were observed in 0, 1, 2, 3, and 4 domains for 58 (25%), 78 (34%), 40 (17%), 33 (14%), and 22 (10%) children, respectively. After adjustment for age, impairment levels varied substantially across DEE group for mobility (p