Interim results of adaptive functioning and neurodevelopment in BUTTERFLY – An observational study of children and adolescents with Dravet syndrome

Joseph Sullivan, Elaine Wirrell, Kelly G. Knupp, Dillon Chen, Muhammad Zafar, Robert Flamini, James Stutely, Charlene Brathwaite, Pam Ventola, Javier Avendaño, Kimberly A. Parkerson, Nancy Wyant, Barry Ticho

Research output: Contribution to journalArticlepeer-review


Purpose: The purpose of this study is to evaluate adaptive functioning and neurodevelopment study assessments in a prospective study of patients with Dravet syndrome (DS). We present 3-month interim adaptive functioning and neurodevelopment data from the prospective, observational BUTTERFLY study in patients with DS aged 2–18 years. Results: BUTTERFLY enrolled thirty-six patients divided 1:1:1 across three age groups (2–7: 8–12: and 13–18 years). Most enrolled patients were female (61.1%), white (94.4%), and non-Latino (83.3%) with a mean (standard deviation; SD) age of 10.8 (5.2) years and a mean (range) age of seizure onset of 0.4 (0.2–1.0) years. Patients used a mean (SD) of 3.5 (1.63) anti-seizure therapies at baseline. Regression analysis of the baseline Vineland Adaptive Behavior Scale – third edition (VABS-III) composite score indicated that the gap in adaptive function between patients with DS (n = 33) and neurotypical children widens with age. Similarly, developmental quotients calculated for patients who completed all Bayley Scales of Infant Development – third edition (BSID-III) subtests at baseline (n = 15) highlighted a gap in intellectual functioning between patients with DS and neurotypical children that widens with age. More patients in the two older age groups were able to validly complete the Wechsler Preschool and Primary Scale of Intelligence – fourth edition (WPPSI-IV) at baseline compared with the youngest age group. There were trends towards higher raw scores, albeit of low magnitude, in the oldest age group compared with the younger age two groups across multiple VABS-III domains and WPPSI-IV subtests. All three measures showed no significant change in the all-patients analyses and demonstrated relatively low intra-patient variability from baseline to Month 3. Conclusions: Three-month interim data from BUTTERFLY demonstrated the feasibility of utilizing the VABS-III, BSID-III, and WPPSI-IV for the assessment of adaptive function and neurodevelopment in future clinical studies of DS. Moreover, many patients with DS appear to gain neurodevelopmental and adaptive function skills over time, although at a slower rate and lower magnitude than that seen in the neurotypical population.

Original languageEnglish (US)
Article number108955
JournalEpilepsy and Behavior
StatePublished - Dec 2022


  • BUTTERFLY study
  • Cognition
  • Dravet syndrome
  • Observational
  • Pediatrics
  • Quality of life

ASJC Scopus subject areas

  • Neurology
  • Clinical Neurology
  • Behavioral Neuroscience


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