A novel clinical test of pointing acuity withopen and closed eyes  a validity study

Abstract: Hand proprioception is crucial for daily activities and may be compromised by diseases or injuries,impacting patients' independence. The lack of feasible, accurate, and affordable clinical tools forhand proprioception assessment poses a significant challenge, essential for identifying dysfunctionand evaluating treatment effects.The purpose of this study was to evaluate the concurrent validity of the LeapMotion controller(LMC) for assessing hand proprioception. We compared the LMC with a 3D camera system formotion analysis (Qualisys Motion Capture, QTM), known for its high measurement accuracy as thegold standard. Twenty participants (10 men, 10 women), 15 without, and 5 with hand injury or pain,took part in this cross-sectional study. Assessments included pointing acuity with open and closedeyes using the right and left hand. There were moderate to good correlations between LMC andQTM performed with closed eyes, with intraclass correlation coefficient (ICC) values of 0.6 and0.89. Contrary, tests with open eyes showed a poor overall correlation with ICC between 0.003 and0.3. Bland-Altman analysis showed median biases of≤ 1.5 mm between LMC and QTM with eyes open, and ≤ 5.1 mm with eyes closed. Limits ofagreement ranged from -0.4 to 3.5 mm with eyes open and -31.6 to 21.5 mm with eyes closed.The results indicate that the LMC could be a cost-effective and feasible tool for quantifying handproprioception with a clinically acceptable bias. Although the median biases were small formeasurements with eyes open, the ICCs were poor. This may be due to a high pointing acuity withinthe group combined with limited variability between the participants in the eyes open tests.