Measuring and modelling arm dynamics to support studies into reducing tremor in individuals with multiple sclerosis

This paper reports on work carried out to date, and future directions for, a project that intends to measure and control tremor in individuals with multiple sclerosis (MS). The project will use computer modelling to simulate the movements involved in upper limb intention tremor, as exhibited by individuals with MS. The models will be incorporated into a final system that will interpret measurements from sets of microelectromechanical systems (MEMS) sensors positioned over the surfaces of the upper limb to provide position, orientation and movement information. These data will be combined with gross muscle activity data, extracted from surface electromyogram (EMG) measurements, to create a fully dynamic model of the arm movements in real time. This model will be used to develop methods of attenuating the tremor, firstly at the elbow joint, without adversely affecting the underlying intended movement, by providing real-time feedback control of appropriate force input devices. The estimates of movement and the forces involved will also provide clinicians with a useful tool in the quantification of upper limb tremor.