Motor development in children with Dravet syndrome

Aim The aim of this study is to describe the course of motor development in children with Dravet syndrome. Method Forty-three participants (21 males, 22 females; mean age at last assessment 53.89mo +/- 42.50mo) met the inclusion criteria of having a confirmed diagnosis of Dravet syndrome and presence of data on motor development. All data between 1985 and 2018 were derived retrospectively from their medical records. Gross motor milestones and motor age equivalents were used to describe motor development. Standardized neurodevelopmental assessment and the Bayley Scales of Infant Development defined the overall motor development. Peabody Developmental Motor Scales, Bruininks-Oseretsky Test of Motor Proficiency, and the Beery-Buktenica Developmental Test of Visual-Motor Integration were used to describe development in specific motor domains. Results Children with Dravet syndrome showed a delay in both sitting (seven out of 14) and walking independently (11 out of 25). Overall motor age equivalents revealed a delay in 29 out of 38 assessments (age 9-115mo). All assessments of children older than 2 years (16 out of 16) showed a delay. Gross motor delay was present in seven out of seven and fine motor delay in 10 out of 13 assessments (age 19-167mo). Interpretation Motor development is delayed in the majority of children with Dravet syndrome older than 2 years and increases with age. What this paper adds A delay in motor development is present in most children with Dravet syndrome older than 2 years. Large diversity in early gross motor milestones confirms heterogeneity in Dravet syndrome.