forceplate: An R package for processing raw force-plate time-series data

Behavior Research Methods, vol. 57, pp. 187

Abstract

Evidence supporting the interaction between cognitive and motor processes is increasing. Conventional approaches to analyze balance control aggregate sway data over seconds up to minutes, which presents a challenge in discerning the impact of single cognitive processes on balance control. In this paper, we propose a novel, event-related approach to investigate how cognitive task performance affects balance control on small time scales using a force plate. A force plate continuously measures forces and moments in each spatial dimension over time. To facilitate the processing of the resulting time-series data, we developed an R-package called forceplate. This package segments the data so that each trial, corresponding to a cognitive task, has its own time-series data. A low-pass filter can be applied to remove artifacts (e.g., muscle twitches or electrical noise), and a baseline correction can be performed to improve the comparability of trials. For each trial's time-series data, user-defined descriptive statistics (e.g., mean or standard deviation) can be calculated for user-defined time bins around an event (e.g., stimulus or response onset). The package generates a dataset with one or more measures per trial (depending on the number of time bins) that can be used for further analysis, such as a (mixed-effects) analysis of variance. The R-package and the described underlying procedure aim to establish a standard to process force-plate data collected in the context of cognitive experiments for the event-related approach. This facilitates the processing of force-plate data and enhances comparability between studies.

Authors 8

1. Raphael Hartmann corresponding

   University of Freiburg

   Affiliation as printed

   University of Freiburg, Freiburg, Germany. raphael.hartmann@psychologie.uni-freiburg.de

2. Anton Koger Aachen

   RWTH Aachen University

   Affiliation as printed

   University of Aachen, Aachen, Germany

3. Elisa Straub

   University of Freiburg

   Affiliation as printed

   University of Freiburg, Freiburg, Germany

4. Leif Johannsen Aachen

   RWTH Aachen University

   Affiliation as printed

   University of Aachen, Aachen, Germany

5. Iring Koch Aachen

   RWTH Aachen University

   Affiliation as printed

   University of Aachen, Aachen, Germany

6. Denise N. Stephan Aachen

   RWTH Aachen University

   Affiliation as printed

   University of Aachen, Aachen, Germany

7. Hermann Müller

   Justus-Liebig-Universität Gießen

   Affiliation as printed

   University of Gießen, Gießen, Germany

8. Andrea Kiesel

   University of Freiburg

   Affiliation as printed

   University of Freiburg, Freiburg, Germany