Abstract
In this study, we investigated how visual feedback regarding pinch force for left and right hand contributes to maintaining and controlling constant force amplitudes. In the present pinch tasks, participants were asked to maintain target pinch force levels for left and/or right hand of 5 or 10% maximal voluntary force (MVF) for 20 seconds. The target amplitudes and current amplitudes of left and right pinch force were displayed with visual cursors. In no visual feedback conditions, one or both side of the cursors disappeared 10 seconds after beginning of the task. Results showed that errors of the pinch force increased as time from disappearance of the feedback cursors, and that variability of the pinch force increased immediately after the disappearance. The errors and variability of the pinch of 10% MVF in no visual feedback condition became largest when accompanied with the pinch of 5% MVF in no visual feedback condition. One side of pinch force with no visual feedback showed better control performance when the other side of visual feedback was available. These results suggest that only one side of the visual feedback aids the maintaining performance of the pinch of the other side with no visual feedback in executing bimanual pinch movements.
