title: Difference in perception of angular displacement according to applied waveforms.
abstract: CONCLUSIONS
  This study shows that the differences in the waveforms of angular rotation affect the perception and memory of angular displacement.
  
  
  OBJECTIVE
  During daily life, when we turn our head during various activities, our brain calculates how much angular displacement our head has undergone. However, how we obtain an accurate estimation of this angular displacement remains unclarified. This study aims to clarify this issue by investigating the perception and memory of passive rotation for three different waveforms of angular velocity rotation (sinusoidal (sine), triangle, and step).
  
  
  METHODS
  Thirteen healthy young subjects sitting on a servo-controlled chair were passively rotated at 60° or 120° about the earth-vertical axis by using one of these three angular velocity waveforms. They then attempted to reproduce the rotation angle by rotating the chair in the same direction in which they had been passively rotated using a handheld controller. The gain (reproduced angle/passively rotated angle) was calculated and used for the evaluation of the perception and memory of angular rotation.
  
  
  RESULTS
  The gain for step rotation was larger than that for sine and triangle rotations, with statistical significance. This confirms that the difference in the waveforms of angular rotation affects the perception and memory of angular displacement.
authors.affiliation: Center for the Promotion of Excellence in Higher Education, Kyoto University, Kyoto, Japan. kushiro.keisuke.5n@kyoto-u.ac.jp
authors.forename: Keisuke
authors.initials: K
authors.lastname: Kushiro
authors.forename: Fumiyuki
authors.initials: F
authors.lastname: Goto
mesh_terms: D000293:Adolescent; D015331:Cohort Studies; D005260:Female; D019416:Head Movements / Q000502:physiology*; D006801:Humans; D008297:Male; D008568:Memory / Q000502:physiology*; D011434:Proprioception / Q000502:physiology*; D012016:Reference Values; D012399:Rotation; D013028:Space Perception / Q000502:physiology*; D014722:Vestibule, Labyrinth / Q000502:physiology*; D055815:Young Adult