Evaluation of task difficulty based on fluctuation characteristics in writing task

Control of voluntary movements is a dual structure of cognitive and physical controls. Cognitive control involves attentional resources, whereas physical control does not. In this study, we evaluated the dependency on attentional resources while learning to perform physical exercises using the relationship between the attentional resources and fluctuations in body movements. The physical exercise to be learned is the process of writing certain Chinese characters by hand. Detrended fluctuation analysis was applied to the analysis of body movement fluctuations in this study. We herein propose an index that qualitatively evaluates fluctuations locally on a timescale and includes a general scaling index on the detrended fluctuation analysis. We investigate and analyze the fluctuation characteristics in the handwriting process of three Kanji characters using this index. Moreover, we examine the relationship among the six handwriting time elements defined in the handwriting process, the handwriting difficulty of the three Kanji characters, and the timescale.