![]() ![]() It has been reported that hearing loss causes a cascade of changes in the main auditory pathway and in non-lemniscal brain regions, such as the hippocampus ( Manikandan et al., 2006 Goble et al., 2009 Cui et al., 2018 Nadhimi and Llano, 2021), a brain structure involved in memory and severely impaired in cognitive decline and AD. Several hypotheses have been proposed to explain the relationship between auditory sensory deprivation and cognitive impairment ( Griffiths et al., 2020 Johnson et al., 2021 Slade et al., 2020), but the nature of such association remains controversial. ![]() Therefore, it is mandatory to clarify the mechanisms linking hearing loss to dementia. Indeed, while it is difficult to counteract neurodegeneration, hearing loss can be considered as a modifiable risk factor, given that it could be widely treated with hearing aids or cochlear implants. Substantiating such correlation would have significant implications for prevention and treatment of dementia. Accordingly, it has been shown that for every 10 dB increase in hearing loss, there is a 20% increased risk of developing dementia ( Lin et al., 2011). Specifically, impairments in peripheral and central auditory structures have been linked to incidence and acceleration of cognitive deficits ( Bernabei et al., 2014 Amieva et al., 2015 Fortunato et al., 2016 Deal et al., 2017) as well as to increased risk for the onset of neurodegenerative disorders including Alzheimer’s disease (AD) ( Gates et al., 2002 Panza et al., 2015 Taljaard et al., 2016 Zheng et al., 2017 Shen et al., 2018). Recent epidemiological evidence suggests a strong association between hearing loss and cognitive decline ( Gallacher et al., 2012 Thomson et al., 2017 Livingston et al., 2020 Loughrey et al., 2018 Liu and Lee, 2019). Our data suggest that a mouse model of AD is more vulnerable to central damage induced by hearing loss and shows reduced ability to counteract noise-induced detrimental effects, which accelerates the neurodegenerative disease onset. This was associated with earlier hippocampal dysfunction, increased tau phosphorylation, neuroinflammation, and redox imbalance, along with anticipated memory deficits compared to the expected time-course of the neurodegenerative phenotype. We found that hearing loss induced by noise exposure in the 3×Tg-AD mice before the phenotype is manifested caused persistent synaptic and morphological alterations in the auditory cortex. To address this issue we investigated the impact of hearing loss on the onset and time-course of cognitive decline in an animal model of Alzheimer’s disease (AD), that is the 3×Tg-AD mice and the underlying mechanisms. Although association between hearing impairment and dementia has been widely documented by epidemiological studies, the role of auditory sensory deprivation in cognitive decline remains to be fully understood. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |