The aim of this study is to develop an adequate part-task trainer occupied with varying levels of severity in spasticity symptoms focusing on the upper limb disorder for occupational therapists. Using the developed part-task trainer, the occupational therapists will have opportunities to repetitively engage in training without patient involvement. The part-task trainer is developed following the structure of human arm articulations with the ability to reproduce the spasticity stiffness. The structured interface programming is built providing three levels of spasticity: mild, moderate and severe. The programming was based on the clinical assessment of spasticity, measuring elbow joint angles and forces exerted by the patients. The recreated spasticity stiffness was evaluated by experienced occupational therapists. Therapists provided positive feedback regarding the mild and moderate level of spasticity leaving further improvement needed in order to reproduce the spasticity at the severe level.