Impact of Congenital Visual Impairment on Early-Life Exploration: Behavioral Analysis of Temporal and Motor Parameters During a Reach-to-Grasp Playful Task.

Reach-to-grasp behavior is a key developmental milestone in infants, involving coordinated actions such as arm transport, hand pre-shaping, and hand opening and closing. Vision guides the development of these skills, and delays in visual input can impact infants with early visual impairments. However, the effects of a congenital visual impairment on reach-to-grasp behavior in early life remain largely unexplored. To address this gap, we compared the reach-to-grasp abilities of sighted (S) and visually impaired (VI) infants and children, focusing on temporal (Movement and Pick-up times) and motor parameters (body midline crossing with one or two hands and hand preference). We hypothesized that VI children would face greater challenges in planning and executing a rapid and accurate reach-to-grasp movement, particularly during the pick-up phase. To investigate this, we asked sighted and VI infants and children to grasp black spheres of different sizes, placed centrally, on the right, or the left of a table in a dimly lit room. Three key findings emerged from our analysis. First, VI children required more time to pick up the spheres compared to their sighted peers. Second, VI children showed a reduced frequency of one-handed body midline crossing when reaching for lateral spheres, but showed an age-related increase, especially when using both hands. Third, VI children showed no hand preference, unlike S children who favored their right hand for crossing the body midline. These results highlight the role of visual experience in developing effective goal-directed movements and support creating early evidence-based rehabilitation procedures. A video abstract of this article can be viewed at https://youtu.be/bjwkMQmdFoE. SUMMARY: Understanding the impact of visual impairment on exploration abilities is crucial, especially in early developmental stages. Currently, there is a significant research gap concerning fine motor skills, particularly reaching and grasping, in visually impaired infants during development. We proposed a playful task to collect behavioral data on reaching and grasping skills in visually impaired children. Results shed light on the pivotal role of visual experience during the first years of life in shaping the maturation of reaching and grasping skills.