Cognitive, language and motor development in toddlers with Down syndrome: Beyond the floor effect of Italian BSID−III scores

Down syndrome is the most common genetic cause of intellectual disability but there are few studies on the development of toddlers with this syndrome. Considering the importance of early interventions aimed at improving the abilities of this population, the purpose of the present study is to assess the cognitive, language, and motor development of a group of 144 Italian toddlers with Down syndrome aged 12−36 months (individually matched for gender, chronological age, and parental education level with typical development toddlers) through the use of the Bayley Scales of Infant and Toddlers Development−III (BSID−III). The assessment of cognitive, language, and motor development of people with low abilities is far from being easy because it is very frequent to find flat profiles, where strengths are obscured and weaknesses are predominant. So, an alternative method of converting raw scores to weighted scores was used to overcome the floor effect of BSID−III scores. Results showed an increase in cognitive and communicative delay evident as early as the second and third years of age and a developmental profile of toddlers with DS characterized by strengths in expressive and receptive communication skills. Results were discussed in reference to the literature in recent years.