The relation between visual functions, functional vision, and bimanual function in children with unilateral cerebral palsy

Background: Accurate visual information is needed to guide and perform efficient movements in daily life. Aims: To investigate the relation between visual functions, functional vision, and bimanual function in children with unilateral cerebral palsy (uCP). Methods and procedures: In 49 children with uCP (7-15 y), we investigated the relation between stereoacuity (Titmus Stereo Fly test), visual perception (Test of Visual Perceptual Skills), visuomotor integration (Beery Buktenica Test of Visual-Motor Integration) and functional vision (Flemish cerebral visual impairment questionnaire) with bimanual dexterity (Tyneside Pegboard Test), bimanual coordination (Kinarm exoskeleton robot, Box opening task), and functional hand use (Children 's Hand-use Experience Questionnaire; Assisting Hand Assessment) using correlations ( r s ) and elastic-net regularized regressions ( d ). Outcomes and results: Visual perception correlated with bimanual coordination ( r s =0.407-0.436) and functional hand use ( r s =0.380-0.533). Stereoacuity ( r s =- 0.404), visual perception ( r s =- 0.391 to-0.620), and visuomotor integration ( r s =- 0.377) correlated with bimanual dexterity. Functional vision correlated with functional hand use ( r s =- 0.441 to-0.458). Visual perception predicted bimanual dexterity ( d =0.001-0.315), bimanual coordination ( d =0.004- 0.176), and functional hand use ( d =0.001-0.345), whereas functional vision mainly predicted functional hand use ( d =0.001-0.201). Conclusions and implications: Visual functions and functional vision are related to bimanual function in children with uCP highlighting the importance of performing extensive visual assessment to better understand children 's difficulties in performing bimanual tasks. What this paper adds: Previous findings showed that up to 62 % of children with unilateral cerebral palsy (uCP) present with visual impairment, which can further compromise their motor performance. However, the relation between visual and motor function has hardly been investigated in this population. This study makes a significant contribution to the literature by comprehensively investigating the multi-level relation between the heterogenous spectrum of visual abilities and bimanual function in children with uCP. We found that mainly decreased visual perception was related to decreased bimanual dexterity, bimanual coordination, and functional hand use while impairments in functional vision were only related to decreased functional hand use. Additionally, elastic-net regression models showed that visual assessments can predict bimanual function in children with uCP, however, effect sizes were only tiny to small. With our study, we demonstrated a relation between visual functions and bimanual function in children with uCP. These findings suggest the relevance of thoroughly examining visual functions in children with uCP to identify the presence of visual impairments that may further compromise their bimanual function.