Sonja Mensch

97 Construct validity and responsiveness Each situation represents a body position with or without the use of an assistive device, consisting of a cluster of items addressing four groups of motor abilities as defined in the International Classification of Functioning, Disability and Health for Children and Youth (ICF-CY) (World Health Organization., 2008): maintaining position, activities, changing body position, and moving around. Questions are asked about the extent to which manual support or support by an assistive device was needed, the activity initiated by the child, and the intensity of active stimulation, i.e. ‘provocation’ of the child with your hands. Because all children have different abilities and different therapeutic goals, only those situations of Movakic that are relevant to the child need to be scored. Therefore, therapists are requested to choose situations relevant to the evaluation of interventions ormonitoring of motor function. A situation could be relevant if a baselinemeasurement is desired for future follow-up, if therapeutic changes are expected in a certain situation, if the therapist is interested in general level of change in motor ability, or a combination of these reasons. Items on the Movakic instrument (Appendix A) are scored on a five- point Likert-type scale, ranging from 0 points, representing the lowest motor function to 4 points, representing the highest motor function. Only one answer per question can be selected by clicking a button. The maximum total scores of the 12 situations differ because of the variable number of items. Therefore, situation scores and total Movakic scores are converted into percentage scores (range 0-100). Procedure Physiotherapists underwent training in use of the Movakic instrument and the study procedure. Participant selection and data collection were performed from August 2010 through October 2011. At baseline, therapists provided information on the child’s sex, age, cognitive developmental age, GMFCS level, diagnosis, comorbid conditions, and assistive devices used. Therapists also provided expert judgment of the child’s motor abilities and Movakic score at baseline. At each of five, 3-month intervals (T1 to T5), therapists again provided expert judgment, repeated the Movakic, and reported on any events theorized to influence motor ability during the previous 3 months. Therapists were requested to choose one relevant Movakic situation, e.g., body position, for each child that was expected to remain stable during follow-up, taking into account unexpected events that could change the chosen situation. At each measurement, the therapists were requested first to provide their judgment of the child’s motor abilities in the chosen Movakic situation, using the Visual Analogue Scale (VAS) (Reips & Funke., 2008). The clinical question to be answered was: ‘Thinking of motor abilities relevant for children with SMD in the chosen Movakic situation, how well is the child able to perform these motor abilities at this moment?’ Physiotherapists