Sonja Mensch

94 Chapter 5 ABSTRACT Movakic is a newly developed instrument for measurement of motor abilities in children with severe multiple disabilities, with a satisfactory feasibility and content validity and good inter-observer and test-retest reliability. The objective of this study was to investigate its construct validity and responsiveness to change. Sixty children with severe multiple disabilities (mean age 7.7 years, range 2-16) were measured using Movakic six times during 18 months. Construct validity was assessed by correlating Movakic scores with expert judgment. In order to assess responsiveness, scores during 3-months intervals were compared (mean score-changes and intraclass correlations) during which some children experienced meaningful events influencing motor abilities and during which others experienced no such event. Forty-five percent of children had a lower cognitive development level than 6-month, 52% had Gross Motor Function Classification System level V and 37% had level IV. For 27 children all measurements were completed, six children dropped out. Construct validity was good ( r = .50 - .71). Responsiveness was demonstrated by significantly larger score changes after events than when such events did not occur. Movakic is a valid instrument for measuring motor abilities in children with severe multiple disabilities. Results suggest responsiveness to change in motor abilities after meaningful events. What this paper adds: The study on psychometric properties of this newly developed instrument supports the use of Movakic in clinical practice in children with severe multiple disabilities. Physiotherapists will be able to detect changes in motor abilities in these children with serious comorbid conditions often leading to a big amount of meaningful events such as surgery, pain or medication change. Key words: Severe multiple disabilities; Motor abilities; Cerebral Palsy GMFCS IV-V; Evaluative instrument; Movakic; Validity Highlights - Movakic is a valid instrument for measuring motor abilities in children with SMD. - Responsiveness seems significant to change in motor abilities after events that likely affect motor abilities. - Physiotherapists are able to useMovakic in clinical practice for the Dutch population. - The English version of Movakic is in progress.