Visual Information Influences Postural Tremor

Open Access
Loncharich, Michael Francis
Area of Honors:
Bachelor of Science
Document Type:
Thesis Supervisors:
  • Karl Maxim Newell, Thesis Supervisor
  • Stephen Jacob Piazza, Honors Advisor
  • tremor
  • visual information
  • interlimb coordination
The dynamics of postural finger tremor is typically investigated with natural vision of the finger. Here we investigated the effects of different types of visual information feedback on postural tremor and on inter-limb postural coordination. There were 4 visual information conditions of postural finger tremor from either the dominant hand only or from both hands. The visual conditions were: 1) no vision; 2) natural vision; 3) augmented vision with instantaneous acceleration on a computer display; and 4) augmented vision with instantaneous and past acceleration on a computer display. Acceleration was measured with a 3D accelerometer on the distal phalanx of the index finger(s). Tremor amount and variability did not change across visual information conditions. However, removing visual feedback increased tremor regularity in the one hand condition. In the two-hand condition the artificial visual information increased the irregularity of the combined tremor variability. The no-vision condition showed a more in-phase relationship between digits than natural vision or artificial vision with past information. The findings showed that augmented visual information increased tremor irregularity and facilitated adaptive coupling in two-hand tremor.