The impact of severe-profound hearing loss and auditory remediation on listening, emotional skills and executive functioning. Mild and long-term outcomes in children, adults and elderly

Sensory systems, like vision and hearing, are fundamental for human beings as they enable to interact with the environment and other human beings. A sensory impairment consequently profoundly impacts general functioning and quality of life of people, involving not only the specific affected sensory system but also the related cognitive functions. Hearing loss is one of the most disabling sensory disfunctions and is considered by the WHO as the fifth most important cause of years lived with disability. The inability to hear sounds and speech, more relevant in severe-profound deafness, results in lack of language acquisition in children and communication disorders in adults, leading to reduced participation to family and social community life, isolation, decreased quality of life, as well as incurrence of costs associated with national health services and social assistance. Due to the efficacy of hearing aids and cochlear implants in restoring auditory input to the brain, the auditory system has become a model for investigating sensory loss, sensory restoration, and related neurocognitive outcomes. The present PhD project describes the experiences and the investigations I had the opportunity to contribute during the three years of my PhD pathway at the Cochlear Implant Centre of the Policlinico Umberto I-University Sapienza, under the supervision of Professor Patrizia Mancini. My research experience was focused on three main themes discussed in three main chapters. The first chapter reports the research that our group conducted in assessing mid- and long-term auditory perception outcomes after cochlear implantation in subjects affected by congenital severe-profound hearing loss, who received surgery during their childhood and grew up using the device. It includes five original studies on quiet and noise speech perception in adolescents and young adults, on music perception and singing skills in school age children, as well as the cross-cultural adaptation and validation of a tool to collect information about listening challenges in school settings. The second chapter deals with the emotional and meta-emotional skills developed by deaf adolescents who were implanted when they were children. It describes the effects of congenital deafness on emotional development, the contribute of restoring auditory input throughout cochlear implantation and the profile of competences reached by cochlear implanted participants in comparison with a group of hearing peers. The third chapter focuses on the effects of auditory deprivation and cochlear implantation benefits on the neurocognitive functions of school age children and elderly. We performed a systematic review and a meta-analysis to draw a picture about the available evidence in literature on executive functions development in cochlear implanted children, we studied the influence of auditory attention on their linguistic outcomes and we tried to describe the differences in cortical EEG patterns during auditory and visual verbal working memory processing between unilateral and bilateral cochlear implanted children. Also, we investigated how attention could influence listening skills in elderly with CI. Finally, given the importance of early intervention, auditory attention and verbal memory were investigated in school age children who were cochlear implanted within 12 months of age to identify a possible benefit in intervening so early when comparing their skills with those achieved by peers who received CI between 13 and 24 months of age.