Assessing Visuomotor Abilities in Cerebral Visual Impairment with Eye and Hand Tracking

Abstract

Cerebral visual impairment (CVI) is a brain-based visual disorder, and visuomotor impairments are often observed. Using wearable eye-tracking technology and hand-focused motion-capture analysis, we characterized gaze and hand movement behaviors during a wooden block-matching puzzle test. 5 subjects with CVI (mean age: 21.20 years ± 4.66 SD, mean MACS: 1.20 ± 0.45) and 9 controls (mean age 21.00 years ± 3.61 SD, mean MACS: 1.00 ± 0.00 SD) participated in the study. For the task, 9 blocks were placed in a starting position, and subjects were required to grasp and place them in their corresponding target position based on their shape and orientation. To examine the effect of cognitive demand, two versions of the task were performed (presented in counterbalanced order), namely, a free task during which subjects selected the blocks at random and a sequenced task during which the blocks were selected in a predetermined order. Gaze behavior was initially recorded using Tobii Pro3 eye-tracking glasses, and videos were then analyzed using a customized MATLAB script that automatically tracked eye gaze, the hand, and the color of each block, enabling the detection of their movements from the starting to the ending position. Results revealed that CVI subjects showed longer latencies between eye and hand movements for both tasks (free: 5.87 sec ± 1.79 SD and sequence: 7.44 sec ± 2.20 SD) compared to controls (free: 4.88 sec ± 1.01 SD and sequence: 5.39 sec ± 1.05 SD). A similar trend was observed with an increased number of saccades for both tasks in the CVI group (free: 55.40 ± 9.53 SD and sequence: 50.80 ± 13.81 SD) compared to controls (free: 40.33 ± 8.80 and sequence: 41.58 ± 10.11 SD). These preliminary results provide objective evidence consistent with eye-hand dyscoordination and, more generally, visuomotor impairments associated with CVI.