Based on the fact that tremors display some distinct 3D spatial
characteristics, we decided to visualize tremor planes in 3D
space. We obtained 3-axial linear accelerometer signals of hand
tremors from 58 patients with Parkinson´s disease (PD), 37 with
isolated resting tremor (iRT), 75 with essential tremor (ET), and
44 healthy volunteers with physiological tremor (Ph). For each
group analysis was done with subsequent spatial 3D regression
of the input data i.e. along the x, y and z axes; the projected
vector lengths in the individual (vertical transversal XY, vertical
longitudinal XZ and horizontal YZ) reference frame planes and
their angles. Most meaningful and statistically significant
differences were found in the analyses of the 3D vector lengths.
The tremor of the PD and the iRT group was oriented mainly in
the horizontal YZ plane. The tremors of the patients with ET and
Ph were oriented approximately in the midway between the all
three referential planes with less tilt toward the vertical
longitudinal XZ plane.