Laura Peeters

The trunk in spinal musclar atrophy | 97 5 with both hands (“Plate”) and bring a cup of 200 grams to the mouth (“Drink”). No instructions were given on how to perform the tasks. Outcome measures Data acquisition and analysis were similar as used in a previous study with healthy children and patients with Duchenne muscular dystrophy, and will be described briefly [9, 13]. Participant characteristics Patient characteristics were recorded based on self-reports and included age, weight, height, arm preference, age of diagnosis (if applicable), wheelchair confinement, pain in upper body at time of participation, scoliosis and spinal fusion surgery. Sitting height was measured and, for patients with SMA, the Vignos lower extremity scale [14] and Brooke upper extremity scale [15] were used for clinical assessment of respectively leg and arm function. Three dimensional motion analysis An optical motion capture system (Vicon Motion Systems Ltd, Oxford, UK) was used to record 13 single reflective markers, which were placed on the skin to define positions and orientations of the trunk and pelvis during task performance. Markers on the spinous processes of C7, T6, T12 and L3, a laterally placed marker at level L1/ L2, jungular notch and xiphoid process of the sternum defined three trunk segments (upper thoracic, lower thoracic and lumbar) [9]. The pelvis markers were placed according to the Vicon Plugin-Gait model with two additional markers on the iliac crest. The markers divided the trunk initially into three segments, because the trunk cannot be seen as rigid segment. However to make the data more concise, we decided to report the trunk movement as one segment (i.e. summation of the three segment angles and pelvis) in this paper. Distribution of movement patterns over the individual trunk segments was essentially the same among HC and patients with SMA without spinal fusion surgery. All kinematic data were filtered with a bi-directional 4 th order Butterworth low-pass filter (cutoff frequency of 6 Hz). Trunk joint angles are expressed relative to the global coordinate system. In all three planes of movement, maximum trunk joint angles were determined when performing the active range of trunk motion tasks. For the reaching tasks and daily tasks, the trunk range of motion (ROM) between the start and end of the task (e.g. time where wrist velocity exceeded/got below 5% of its peak velocity) was determined.