Sonja Mensch

105 Construct validity and responsiveness CONCLUSION Evaluating change in children with SMD is a challenging task due to the complexity of comorbid conditions and variety of interventions aimed to improve function or increase comfort. GivenMovakic’s feasibility and content validity (Mensch et al., 2015c), reliability (Mensch, Rameckers, Echteld & Evenhuis., 2015b), and the results of the current study, we recommend the instrument for use in clinical practice and research. Physiotherapists should have ample experience with children with SMD, and should be familiar with the individual child they measure using Movakic. In the process of implementing Movakic in clinical practice, therapists need to be trained in correct use of Movakic. A two-day training course was developed in the Netherlands, and translation of the instrument in English is in progress. Furthermore, in future studies using specific interventions, we recommend focusing on clarifying the interpretation of the changes in Movakic score. Acknowledgements Ipse de Bruggen, care organization for people with intellectual disabilities and Nuts Ohra Fund (nr 1102-045) financed this research. The authors are grateful to the participating therapists for their accurate and convincing collaboration. These participating therapists were from different care organizations all over the Netherlands; Stichting Omega, ‘s Heeren Loo, ASVZ, Zozijn, Stichting Tragel, NOVO, SWZ, Esdégé Reigersdaal, Kempenhaeghe, Kleur (Dichterbij), Schutse, ZMLK school de Kom, Gemiva- SVG, De Hartekamp groep, stichting de Driestroom and Ipse de Bruggen. In addition, the authors pay tribute to Rob Rieken for his detailed editing. Declaration of interests We certify that no party that contributed to the results of this research has or will benefit from its publication nor will any organization with which we are associated. We agree this paper meets the standards of expected ethical behaviour. If applicable, we certify that all financial and material support for this research and work are clearly identified in the title page of the manuscript. Conflicts of interest: none to declare.