Influence of Visual Perturbation on Reaching Accuracy in a Novel Dynamic Reaching Test Mimicking Ball Catching in a Virtual Reality Environment.

The purpose of the current study was to explore vision-proprioception integration patterns during a novel dynamic reaching test and a shoulder joint repositioning accuracy (JRA) test in virtual reality (VR). Twenty-seven physically healthy individuals performed the dynamic reaching test and JRA test, while vision of their tested hand position was manipulated in VR. Hand positions in both tests were captured with trackers on the participant's wrist, and the hand position was either projected accurately (accurate vision block; AB), not projected (no vision block; NB), or projected with an 8° offset (offset vision block; OB) relative to the wrist tracker position. In the dynamic reaching test, spatial reaching errors significantly differed in OB compared to AB and NB (p = . 008), as the mean value of each condition was 1.8° in AB, 1.2° in NB, and ‒1.5° in OB. Temporal reaching errors did not show significant differences among the visual conditions (p > .1), with mean values of ‒0.1 s in AB, ‒0.2 s in NB, and ‒0.2 s in OB, where the negative values indicate that the hands arrived at the hand-target interception points earlier than the target. In the JRA test, participants also had a larger repositioning error in OB than AB (p < .001), as the mean value for each condition was ‒0.8° in AB and ‒8.9° in OB. Significant differences in spatial reaching and repositioning errors in the dynamic reaching and JRA tests indicate influences of inaccurate vision on the reaching hand position.