La repondération sensorielle chez les adultes ayant une presbyacousie, porteurs ou non-porteurs d'appareils auditifs

Abstract

Les risques de chutes, chez les adultes de plus de 40 ans, suscitent une préoccupation à l’échelle mondiale en raison de leur impact sur la santé individuelle et les systèmes de santé. Le déclin du contrôle postural dû à l’âge est un facteur de risque majeur associé à une augmentation du risque de chutes. Un autre facteur contribuant au risque accru de chutes est la perte auditive. Bien que le contrôle postural repose sur une boucle de rétroaction continue intégrant principalement les informations somatosensorielles, visuelles et vestibulaires, des recherches récentes indiquent que les informations auditives jouent un rôle dans la stabilisation et l’orientation du corps dans l’espace. La presbyacousie détériore progressivement ces informations auditives avec l’âge, et pourtant, son impact sur le contrôle postural demeure à ce jour peu compris. En effet, il demeure difficile de comprendre le rôle de la modalité auditive dans le contrôle postural et son poids relatif par rapport aux autres modalités sensorielles (pondération sensorielle), notamment chez les adultes âgés. La première étude vise à examiner l’impact de la presbyacousie sur le contrôle postural et la pondération sensorielle. Les performances posturales d’adultes âgés, avec ou sans presbyacousie, ont été comparées à celles de jeunes adultes ayant une acuité auditive normale afin de distinguer les effets de l’âge des changements pathologiques causés par la presbyacousie. Par ailleurs, si la presbyacousie réduit le contrôle postural et augmente les risques de chute, alors une restauration des informations auditives visant à corriger cette presbyacousie pourrait contribuer à diminuer ces risques. Ainsi, des interventions telles que le port d’appareils auditifs pourraient aider à prévenir les chutes en améliorant le contrôle postural tout en corrigeant la presbyacousie. The risks of falls in adults over the age of 40 are a global concern due to their impact on individual health and healthcare systems. The consequences of falls, such as occupational injuries, hospitalizations, and mortality, emphasize the need to identify risk factors and develop prevention strategies to reduce these risks. It is well-established that age-related decline in postural control is a common risk factor associated with an increased risk of falls. While postural control relies on a constant feedback loop involving primarily somatosensory, visual, and vestibular information, recent studies suggest that auditory information contributes to maintaining postural stability by orienting or stabilizing the body in space. Furthermore, hearing loss, particularly presbycusis, which progressively impairs auditory information with age, is associated with an increased risk of falls. However, the underlying mechanisms linking hearing loss and postural control remain poorly understood. Understanding the role of the auditory modality in postural control is challenging, given the sensory weighting processes that determine its relative importance compared to other sensory modalities. The first study aims to examine sensory weighting for postural control in older adults with and without presbycusis compared to young adults with normal hearing, to distinguish age-related changes from pathological changes caused by presbycusis. Moreover, considering that presbycusis is linked to a higher risk of falls, restoring auditory information in adults with presbycusis could help reduce the risk of falls in this population. Interventions such as wearing hearing aids may prevent falls by improving postural control while correcting presbycusis. The second study focuses on the impact of hearing aid use on sensory weighting for postural control in individuals with presbycusis. Overall, our results have demonstrated that the reduction or restoration of auditory information affects the maintenance of postural stability, particularly when information from other sensory modalities is degraded. Indeed, our study is the first to demonstrate the impact of presbycusis on the inappropriate increase in somatosensory reweighting, which may explain the decline in postural control observed in older adults with presbycusis. Our findings also support that restoring auditory information with hearing aids induces appropriate changes in sensory reorganization, contributing to improved postural control in adults with presbycusis. This thesis will contribute to a better understanding of the impact of presbycusis on postural control and highlight the potential of hearing aids as a preventive intervention for falls in older adults. The obtained results will help develop more effective fall prevention strategies and enhance the safety and quality of life of individuals with presbycusis.