Independent walking and cognitive development in preschool children with Dravet syndrome

Aim: To investigate the relation between cognitive and motor development in preschool aged children with Dravet syndrome, in particular between the age of independent walking and cognitive development. Method: Results of cognitive and motor developmental assessments and the age of independent walking were retrieved retrospectively from the medical records of 33 children (17 males, 16 females; mean age at last evaluation 33.2mo, SD 8.2mo, range 9–48mo) diagnosed with Dravet syndrome. Cognitive and motor developmental age, derived from the Bayley Scales of Infant Development or through standardized neurodevelopmental assessment, were converted into cognitive and motor developmental quotients. Multiple test scores per child were included. Results: A strong positive relation was found between cognitive and motor developmental quotient (Pearson r=0.854; p<0.001) in 20 children (slope=0.75; 95% CI: 0.54–0.95). A later age of independent walking was associated with a lower cognitive developmental quotient (28 children; p<0.001; slope=−1.01; 95% CI: −1.53 to −0.49). A higher cognitive developmental quotient was seen in children with an age at testing younger than 24 months. The cognitive developmental quotient of children with a delay in independent walking (>17.6mo) was significantly lower than those without a delay (p=0.006). Interpretation: A strong relation exists between cognitive and motor development. Furthermore, the age of independent walking might be an important indicator of the development of children with Dravet syndrome.