Background: During the first year of life, infants undergo crucial stages in the development of language perception, linked to fundamental neural changes. This period is critical for sensitivity and interaction with the linguistic environment. Near-infrared spectroscopy (NIRS) is an advanced tool for studying brain activity and the development of language areas in children. Hearing impairment and prematurity can significantly influence perceptual development, making early study of these anomalies essential for better understanding their impact on neurobiological and communicative development. Aim of the study: The purpose of this study is to investigate whether differences in language discrimination observed in premature infants persist during the first year of life. In particular, the objective is to evaluate the ability to distinguish between two rhythmically different languages (Italian and English) and the ability to discriminate between normal speech (forward) and reversed speech (backward). Two groups will be compared: premature infants with normal hearing compared to full-term infants of the same age, and premature infants who are deaf compared to other deaf full-term children of the same age. Materials and methods: Thirty-four premature subjects were initially tested, out of which 22 were included in the statistical analysis. These 22 subjects were divided into 13 with normal hearing and 9 with deafness. Subsequently, 4 control groups were created—2 for deaf and 2 for normal hearing subjects—matching the premature subjects in number: one group matched for chronological age and the other for corrected age based on weeks of prematurity. The brain areas responsible for hearing and language, specifically the fronto-temporal cortex, were examined using fNIRS technology. During the experiment, brain activity was recorded while participants were exposed to linguistic stimuli in Italian (their native language) and English (an unfamiliar language), spoken normally and backward for control purposes. The collected data were analyzed using MATLAB, corrected for artifacts, and then subjected to further analysis. Results: The analyses showed a language effect in all groups, both normal-hearing and deaf, when language was presented. This effect was always left-lateralized, consistent with previous studies. The groups of normal hearing children appeared to be more engaged by listening to the English language. Both normal-hearing and deafs groups of premature children did not show any directional effect in discriminating language from non-language. Conclusions: The study demonstrated that both normal-hearing and deaf subjects activate neural networks in response to language. The presence of prematurity does not alter this dynamic, which also occurs in populations of premature children. The analyses revealed that premature children, whether normal-hearing or deaf, have difficulty distinguishing language from non-language, and therefore, in discerning direct speech from reverse speech.
Introduzione: Durante il primo anno di vita, i neonati attraversano tappe cruciali nello sviluppo della percezione del linguaggio, legate a cambiamenti neurali fondamentali. Questo periodo è critico per la sensibilità e l'interazione con l'ambiente linguistico. La spettroscopia nel vicino infrarosso (NIRS) è uno strumento avanzato per studiare l'attività cerebrale e lo sviluppo delle aree linguistiche nei bambini. L'ipoacusia e la prematurità possono influenzare significativamente lo sviluppo percettivo, rendendo fondamentale lo studio precoce di queste anomalie per comprendere meglio il loro impatto sullo sviluppo neurobiologico e comunicativo. Scopo dello studio: Lo scopo di questo studio è indagare se le differenze nella discriminazione del linguaggio, osservate nei bambini prematuri, persistano durante il primo anno di vita. In particolare, si intende valutare la capacità di distinguere tra due lingue ritmicamente diverse (italiano e inglese) e la capacità di discriminare tra il parlato normale (forward) e il parlato al contrario (backward). Verranno confrontati due gruppi: prematuri normoudenti con coetanei nati a termine e prematuri sordi con altri bambini sordi nati a termine. Materiali e metodi: Sono stati testati 34 soggetti prematuri di cui poi 22 sono stati inclusi nell’analisi statistica. I 22 soggetti erano divisi in 13 normoudenti e 9 ipoacusici. Successivamente, sono stati creati 4 gruppi di controllo, 2 di ipoacusici e 2 di normoudenti, della stessa numerosità dei soggetti prematuri: uno corrispondente per età cronologica e l’altro per età corretta rispetto alle settimane di prematurità. Le aree cerebrali responsabili dell'udito e del linguaggio, ossia la corteccia fronto-temporale, sono state esaminate utilizzando la tecnologia fNIRS. Durante l'esperimento, è stata registrata l'attività cerebrale mentre i partecipanti venivano esposti a degli stimoli linguistici in italiano (la loro lingua madre) e in inglese (una lingua sconosciuta), pronunciate normalmente e al contrario come controllo. I dati raccolti sono stati poi analizzati con MATLAB, corretti dagli artefatti e successivamente analizzati. Risultati: Le analisi hanno mostrato in tutti i gruppi, sia normoudenti che ipoacusici, un effetto di lingua alla presentazione del linguaggio. Tale effetto si è dimostrato essere lateralizzato sempre a sinistra, in accordo con i precedenti studi. I gruppi di bambini normoudenti sembrano essere più portati dall’ascolto della lingua inglese. I gruppi di bambini prematuri, sia normoudenti che ipoacusici, non hanno mostrato alcun effetto di direzione ovvero nella discriminazione del linguaggio dal non linguaggio. Conclusioni: Lo studio ha dimostrato che sia i soggetti normoudenti che quelli ipoacusici attivano le reti neurali in risposta al linguaggio. La presenza di prematurità non altera tale dinamica che si verifica ugualmente anche nelle popolazioni di bambini prematuri. Dalle analisi è emerso che i bambini prematuri, sia normoudenti che ipoacusici, mostrano difficoltà nel distinguere il linguaggio dal non linguaggio, dunque, nel discernere il discorso diretto dal discorso inverso.
Valutazione della discriminazione del parlato in soggetti prematuri e ipoacusici nel primo anno di vita usando la spettroscopia nel vicino infrarosso
FANTE, SILVIA
2023/2024
Abstract
Background: During the first year of life, infants undergo crucial stages in the development of language perception, linked to fundamental neural changes. This period is critical for sensitivity and interaction with the linguistic environment. Near-infrared spectroscopy (NIRS) is an advanced tool for studying brain activity and the development of language areas in children. Hearing impairment and prematurity can significantly influence perceptual development, making early study of these anomalies essential for better understanding their impact on neurobiological and communicative development. Aim of the study: The purpose of this study is to investigate whether differences in language discrimination observed in premature infants persist during the first year of life. In particular, the objective is to evaluate the ability to distinguish between two rhythmically different languages (Italian and English) and the ability to discriminate between normal speech (forward) and reversed speech (backward). Two groups will be compared: premature infants with normal hearing compared to full-term infants of the same age, and premature infants who are deaf compared to other deaf full-term children of the same age. Materials and methods: Thirty-four premature subjects were initially tested, out of which 22 were included in the statistical analysis. These 22 subjects were divided into 13 with normal hearing and 9 with deafness. Subsequently, 4 control groups were created—2 for deaf and 2 for normal hearing subjects—matching the premature subjects in number: one group matched for chronological age and the other for corrected age based on weeks of prematurity. The brain areas responsible for hearing and language, specifically the fronto-temporal cortex, were examined using fNIRS technology. During the experiment, brain activity was recorded while participants were exposed to linguistic stimuli in Italian (their native language) and English (an unfamiliar language), spoken normally and backward for control purposes. The collected data were analyzed using MATLAB, corrected for artifacts, and then subjected to further analysis. Results: The analyses showed a language effect in all groups, both normal-hearing and deaf, when language was presented. This effect was always left-lateralized, consistent with previous studies. The groups of normal hearing children appeared to be more engaged by listening to the English language. Both normal-hearing and deafs groups of premature children did not show any directional effect in discriminating language from non-language. Conclusions: The study demonstrated that both normal-hearing and deaf subjects activate neural networks in response to language. The presence of prematurity does not alter this dynamic, which also occurs in populations of premature children. The analyses revealed that premature children, whether normal-hearing or deaf, have difficulty distinguishing language from non-language, and therefore, in discerning direct speech from reverse speech.| File | Dimensione | Formato | |
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https://hdl.handle.net/20.500.12608/67054