Fig 1.
Apparatus used in the experiment (exemple for a right-handed participant).
a-b) Set-up of the vibrator. A black curtain covered the forearm of the participant. c-d-e) Visualization of the three virtual visual conditions (respectively Moving, Hidden, Static condition). A black arrow (not visible during the experiment) indicates the movement of the wrist in the Moving condition, from flexion to extension. f) Measure of sensation of displacement with the protractor. « -90° » indicates an extreme wrist extension in the case of a left upper limb. The notes «values of degree» and « wrist extension, wrist flexion » are not visible by the participant during the experiment.
Fig 2.
Description of the moving condition.
Movement from wrist flexion to wrist extension, with a total displacement of 30 degrees around the rest position. The values and arrow are not visible by the participant during the experiment.
Fig 3.
Pictures of the vibratory device UniVibe™.
a) Raw vibration motor. b) Vibration motor device linked to the Arduino® and inside a sound box. c) Wrist placement.
Fig 4.
Flowchart of the experiment.
Fig 5.
Frequency of sensation of wrist extension.
Smoothed histogram of the frequency of sensation of wrist displacement in each condition averaged in healthy controls. The vertical line represents the zero degree axis.
Fig 6.
Intensity of illusion of movement.
Boxplot about intensity of illusion of movement felt for each condition, averaged in all healthy controls (respectively for Moving, Hidden, Static condition). Likert scale from 1 to 7: 1 means “no illusion”, 7 mean “very high intensity of illusion”. The dots represent the means.