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.