Dottorato in NEUROSCIENZE CLINICO-SPERIMENTALI E PSICHIATRIA

Titolo della tesi: Audiometria vocale adattiva, abilità linguistiche e funzioni cognitive nei giovani adulti impiantati in età infantile

During the three years of the PhD program, I focused on the field of auditory perception, in particular on cochlear implant patients. Auditory perception is critical for human communication and interaction. Cochlear implants have been crucial in the treatment of severe or profound deafness, but individual patient variables influence their success. These variables include subjective aspects such as motivation and cognitive variables such as attention and memory. Hearing loss in the elderly has a significant impact on quality of life, contributing to social isolation, anxiety, and depression. The treatment approach should be multidisciplinary, considering audiological, cognitive, and psychological aspects. The literature reported a potential link between presbycusis (age-related hearing loss) and cognitive decline. The prevalence of hearing loss in childhood is about 1.5 cases per 1000 live births. About 30% of deaf children also have a history of additional disability, frequently cognitive retardation. Congenital hearing loss can have significant effects on the development of language, communication, cognition, and education, with potential long-term consequences. Several studies have shown that early detection and early intervention are important for the proper language and cognitive development of children with hearing loss. Age at implantation is a critical factor in achieving optimal results in children with cochlear implants. Early intervention harnesses brain plasticity and improves the chances of a good auditory and language experience. BACKGROUND: The primary aim of the study was to assess the long-term speech perception outcomes (in quiet and noise) and language skills in a sample of prelingually deaf young adults who received their cochlear implant (CI) during childhood. The secondary aim was to determine if and to what extent speech perception in adulthood was related to the age at implantation and morphosyntactic comprehension skills. In addiction, the study evaluated fluid intelligence and executive functions, particularly working memory (WM) of long-term CI users and the relationship with speech perception in noise and language skills. MATERIALS AND METHODS: A prospective cohort study of 60 young adult CI users, 34 unilateral and 26 bilateral (mean age at surgery 57.7 ± 47.49 months; mean age at the last follow-up assessment 22.64 ± 3.8 years, and mean follow-up 21 ± 19.72 years). The Shapiro-Wilk test was used to assess normal data distribution (p-value ≤ 0.05). Kruskall Wallis and Mann-Whitney tests were used to compare listening modes, demographic variables, audiologic variables, linguistic variables, and cognitive variables. Bivariate analysis was performed to investigate the relationship between It-Matrix and TROG-2 and Peabody with perceptive and cognitive audiologic variables. Multivariate analysis was performed to quantify the relationship between a dependent variable (TROG-2, Peabody, and It-Matrix) and a set of explanatory variables (age at cochlear implant, speech perception in quiet and noise, language skills, cognitive functions) using a hierarchical stepwise linear regression. RESULTS: Bivariate analysis showed that It-Matrix was positively correlated with age at implantation (age CI r=0.38 p: 0.004) and auditory attention (r= 0.49 e p: 0.006). Audiologic results in noise and in quiet were strongly correlated with It-Matrix test results (p < 0.01), and PCA sentences were strongly correlated with TROG-2 and Peabody (p < 0.01). Morphosyntax (TROG-2) was negatively correlated with It-Matrix test results (TROG-2 r = - 0.5; p <0,001). Linguistic variables (TROG-2 and Peabody) were strongly correlated with the Listening Span Test and SPM with a p-value of < 0.01. CONCLUSIONS: These long-term data help us increase our understanding of the effects of variables such as the age at cochlear implantation or bilateral implantation on the outcomes of auditory rehabilitation with cochlear implants. The study also provides information on how language perception and language development are mutually related and, most importantly, further confirms that language perception in noise is influenced not only by several years of experience with the cochlear implant and the achieved language but also by other factors like higher cognitive functions.