Developmental trajectories in visually impaired children: towards new early intervention strategies

Vision has a crucial role in mediating the early interactions between an infant and the surrounding world, arousing the child’s first object relations and mental representations, and letting the objects be perceived in a syncretic way, providing all their essential information at once. The pivotal role of vision on relational, emotional, cognitive, and motor development has been extensively studied. Behavioral and neurophysiological studies have suggested the existence of a “critical period” in which neural plasticity has its maximum expression and early-onset blindness can impact on the shaping of an individual’s development. In the last decades, many authors have focused on the possible negative effects of visual impairment (VI) on different aspects of neuropsychomotor development. However, the results of the studies often pose questions on their interpretation as they reflect the complexity of the visual system. Moreover, very few studies exist on the mechanisms underlying the effects of sensory deprivation, as few are reports on developmental outcomes in school-age children and adolescents. The main goal of this thesis carried out during my PhD program is to deepen the knowledge of the developmental trajectories of children with congenital or early acquired VI, to respond to some unmet needs of these children and their families. This objective is divided into different sub-objectives: a) investigating the effects of different forms of visual impairment on different domains of neuropsychomotor development, also exploring their anatomic-functional correlates; b) developing assessment and outcome measures for visually impaired children and adolescents; c) exploring the role of science-driven technologies based on a multisensory approach in their assessment and re-habilitation. Chapter 1 summarizes the main research findings on the impact of VI on development, the currently unmet needs, and the possible role of re-habilitation. Chapters 2, 3, and 4 present the main results of studies carried out during my PhD course. Overall, my PhD project was conceived as part of translational research (i.e., based on a constant interplay between care and research). It was carried out at the Developmental Neuro-ophthalmology Unit of IRCCS Mondino Foundation, a center for the diagnosis and re-habilitation of neuroophthalmological disorders that works within the ICF-CY framework. The studies presented in Chapter 2 resulted in the description of the neuropsychological, emotional, and behavioral profiles of VI across childhood and adolescence. Moreover, studies on the neural correlates of these developmental trajectories are presented. Chapter 3 describes the development of two clinical tools for the assessment of visual function and autonomies. These tools respond to the need for specific and comprehensive measures of the developmental outcomes and the efficacy of interventions. Chapter 4 presents two novel technological systems based on multisensory stimulation, designed to measure and train perceptual and spatial competencies in VI. Finally, Chapter 5 summarizes the findings reported in the previous Chapters, paving the way for prospective clinical studies implementing neurophysiological and neuroimaging protocols and re-habilitation trials with the help of new technologies.