Laura Peeters

1 General Introduction | 15 children below the age of 9.5 years. New natural history studies have to give insight in the long-term effects of the treatment. AIM OF THIS THESIS For the development and evaluation of assistive devices and other interventions for the trunk and UE in people with NMD, it is important to increase our knowledge of trunk function and the functional interactions between trunk, head and UE movements when performing seated daily tasks. Specifically, better insight in the commonalities and differences in trunk function among patients with different types of NMD, and between NMD patients and healthy controls is essential. Such knowledge provides clinicians and engineers with clues about which aspect of treatment (e.g. physical training, seating adjustments or assistive devices) can be generalized to all patients and where individual adaptations are needed. The following research questions were formulated: • What is known about the interactions between trunk, head and UE movements in patients with a flaccid trunk? • How are the trunk and head involved in performing seated tasks with the UE in typically developing children and young adults; and more specifically, what is the role of specific trunk segments? • How does trunk function differ between patients with DMD, patients with SMA, and healthy subjects during seated tasks with the UE? MEASUREMENT METHODS In this thesis, several outcome measures are useto answer the above questions, such as joint torque, joint range of motion, and muscle capacity. These outcome measures were determined with the use of muscle strength testing, movement analysis, and electromyography. Muscle strength testing Muscle strength testing is often used in the clinic to monitor disease progression. Muscle strength is clinically measured with the Medical Research Council (MRC) ordinal scale [28]. More precise measurement of muscle strength can be done with the use of a hand-held dynamometer (HHD) or with a static frame myometer. The HHD is less reliable amongst different examiners and for assessing large muscle