The video illustrates a real-time algorithm to characterize pathological tremor, while filtering voluntary motion components. The method was designed to support active tremor compensation systems.
You can find detailed info on the corresponding paper1.
References
1.
Bo, A. P. L., Poignet, P. & Geny, C. Pathological tremor and voluntary motion modeling and online estimation for active compensation. IEEE Transactions on Neural Systems and Rehabilitation Engineering 19, 177–185 (2011).