• multisensory integration
• neurodevelopmental disabilities
• visual deficit

The general aim of this PhD thesis is to study and analyze Multisensory Processes (MP) in typical and atypical development, within a model of therapeutic intervention for children. In accordance with the outlines of this thesis, MP could be considered a keystone for the enhancement of brain plasticity even in the presence of congenital or acquired neurological
disorders. The current literature underlines the crucial role of early intervention for improving the long-term outcome of children at-risk for neurodevelopmental disability (Blauw-Hospers, Dirks, Hulshof, Bos, & Hadders-Algra, 2011; Cioni, D'Acunto, & Guzzetta, 2011; Guzzetta et al., 2009; Sgandurra et al., 2016), but a considerable line of research also supports the idea that it is possible, even in adulthood, to improve the performance of patients with chronic neurosensory deficits, in particular with cerebral visual disorders by using therapeutic strategies based on multisensory integration (Bolognini, Rasi, Coccia, & Ladavas, 2005; Dundon, Bertini, Ladavas, Sabel, & Gall, 2015; Keller & Lefin-Rank, 2010; Targher, Occelli, & Zampini, 2012).
During my PhD course, I focused on the topic of multisensory perception and whether it facilitates adaptation to the environment in subjects with neurological disorders.
In the first study, the aim was to explore the effects of an early multisensory intervention, based on body massage, on the development of visual function in infants with genetic neurodevelopmental disabilities, specifically with Down syndrome (DS). The results showed that the Environmental Enrichment protocol, based on multisensory infant massage, affects the maturation of visual functions in human infants with DS, as has already been demonstrated in preterm infants (Guzzetta et al., 2009). The infants in the Experimental Group showed an accelerated development in visual acuity up to at least 12 months and also stereopsis had an earlier onset, compared to Controls.
The second study focused on the implementation of a multisensory stimulation training programme in children and adults with visual field defect, after brain injury. This type of rehabilitation approach was first implemented by Bolognini and collaborators with adult patients (Bolognini, Rasi, Coccia, et al., 2005). At the beginning of this chapter, its use with children with acquired visual field defects is described. The results confirm the amelioration in visual target detection and visual search abilities in children. Subsequently, the audiovisual stimulation training was performed with a new tool, which was designed to be implemented at home through a telerehabilitation programme. The impact of this intensive multisensory stimulation on patients was investigated by studying the improvement in behavioural tasks, and by analyzing a potential change in brain activity at fMRI, before and after training. The results were positive and suggested new hypotheses on the neurofunctional mechanisms underlying plasticity and multisensory integration.
The third study aimed mainly to study how multisensory integration skills (specifically visuo-haptic integration) influence recognition of everyday objects in typically developing children and whether the developmental trajectory of this multisensory modality differs from unisensory modalities in typical preschool and school-aged children. According to our results, 4-5 year-old children are already able to benefit from multisensory integration in object recognition tasks and the results show important differences between unimodal and bimodal sensory abilities, but this process appears to be very complex and long, indeed it continues to develop during the entire school period.
The introduction of this PhD thesis briefly presents the scientific literature on the development of MP both in typical children and in the presence of visual disorders.