Functional and structural brain connectivity in congenital deafness.

Karolyne Dell Ducas,Renata Ferranti Leoni,Kaio Felippe Secchinato,Antonio Carlos Santos,Pedro Henrique Rodrigues Silva,Antonio Carlos Da S Senra Filho

doi:10.1007/s00429-021-02243-6

Karolyne Dell Ducas, Renata Ferranti Leoni + Show 4 more

Open Access

https://doi.org/10.1007/s00429-021-02243-6

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Abstract

Several studies have been carried out to verify neural plasticity and the language process in deaf individuals. However, further investigations regarding the intrinsic brain organization on functional and structural neural networks derived from congenital deafness are still an open question. The objective of this study was to investigate the main differences in brain organization manifested in congenitally deaf individuals, concerning the resting-state functional patterns, and white matter structuring. Functional and diffusion magnetic resonance imaging modalities were acquired from 18 congenitally deaf individuals and 18 age-sex-matched hearing controls. Compared to the hearing group, the deaf individuals presented higher functional connectivity among the posterior cingulate cortex node of the default mode network with visual and motor networks, lower functional connectivity between salience networks, language networks, and prominence of functional connectivity changes in the right hemisphere, mostly in the frontoparietal and temporal lobes. In terms of structural connectivity, we found changes mainly in the occipital and parietal lobes, involving both classical sign language support regions as well as concentrated networks for focus activity, attention, and cognitive filtering. Our findings demonstrated that the congenital deaf individuals who learned sign language developed significant brain functional and structural reorganization, which provides prominent support for large-scale brain networks associated with attention decision-making, environmental monitoring based on the movement of objects, and on the motor and visual controls.

Highlights

Hearing is one of the essential parts of human communication, offering the possibility to differentiate speech sounds
When we focus on the default mode network (DMN) nodes, composed by the Posterior Cingulate Cortex (PCC), medial Prefrontal Cortex, and right and left lateral parietal regions
The deaf group presented higher Functional connectivity (FC) among salience, dorsal attentional, and frontoparietal networks when compared to the hearing group

Summary

Introduction

Hearing is one of the essential parts of human communication, offering the possibility to differentiate speech sounds. Language difficulties found in deaf children are completely preventable, since the major cause of social isolation is the lack of early exposure to a language form accessible to their natural abilities (Mayberry et al, 2002). It is well-known that deaf children require a rich and fruitful linguist environment that is adaptable to their sensorial capabilities, mainly in the early years of life (Petitto 1994; Petitto et al 2000; Mayberry et al 2002; Neville and Bavelier 2002; Schick et al 2010). Early diagnosis is one of the decisive factors, since the neurological maturation responsible for the cognitive development associated with language occurs in childhood (Gazzaniga 2000)

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