Movement Disorder Assessment and Attenuation Techniques for Removal of Tremor

Abstract

A weighted-frequency Fourier linear combiner (WFLC) filter is used for removal of tremor motion for data captured from movement disorders subjects with essential tremor (ET) and Parkinson's disease (PD). This technique is applied here in six degrees-of-freedom and data are filtered so that a comparison can be made before and after filtering to assess the extent to which the WFLC filter removed tremor. A wavelet spectral analysis is employed to determine the effectiveness of the filter in removing tremor in the 3-12 Hz band of interest. A Kalman filter is employed to improve data processing so that six degree-of-freedom tremor motion can be accurately rendered for subsequent filtering; such accurate rendering is needed so that full tremor motion can be adequately described. A Fourier coherence based technique is utilized so that relationships for interrelated tremors for the different six degrees-of-freedom can be identified. Much of the analysis shown is novel.

Inertial Sensing to Determine Movement Disorder Motion Present before and after Treatment

“…Other combinations of sensors can also be used to provide similarly useful coherence plots, but the x-accelerometer data and y-gyroscope data were particularly good for this purpose partly because the x-accelerometer logged the most lateral tremor and the y-gyroscope logged the most rotational tremor. Also, these two signals were especially good for coherence analysis because the tremor motion that they logged tended to be of a consistent phase shift [ 24 ].…”