Inertial sensor based quantitative assessment of upper limb range of motion and functionality before and after botulinum toxin: a pilot study

Botulinum toxin (BTX) treatment of upper limb is considered effective for upper limb spasticity following stroke and brain injury. Traditional method - Modified Ashworth Scale (MAS) is widely used for assessment of spasticity, however, it suffers from limitations including the lack of objective outcome measures and ignorance of the active movements. This pilot study is to develop a quantitative assessment utilizing inertial sensors tool for upper limb movement measurement and to investigate an objective measure of upper limb function for neurological patients before and after BTX treatment of spasticity. The system we proposed provides kinematic measurements of upper limb segment and joint motion data. In this study, four stroke patients were assessed by our proposed inertial sensing system immediately before and one week after BTX injection. In addition, patients were assessed using clinical assessment scales e.g. MAS, Disability Assessment Scale (DAS) and Motor Assessment Scale. The results showed that elbow Active Range of Motion (AROM) increased by 19 degrees on average and MAS and Motor Assessment Scale scores did not show significant change. The changes of the kinematic measures for patients 1-3 e.g. AROM, Rate of change of elbow joint angle, NJS, MUN and S-ratio all show that the inertial system is able to identify improvement in performance. This inertial sensing system provides additional and novel dynamic motion data for a sensitive and quantitative assessment of response to treatment and the efficacy of post-injection physiotherapy.