Gray Matter Declines with Age and Hearing Loss, But Is Partially Maintained in Tinnitus

This is a new research paper by Elouise Koops (winner of the Danny Boy Memorial Fund), published in Scientific Reports.


Full text: https://www.nature.com/articles/s41598-020-78571-0

Abstract
The impact of age-related hearing loss extends beyond the auditory pathway and impacts brain areas related to cognitive impairment and even dementia. The presence of tinnitus, a sensation of sound that frequently co-occurs with hearing loss, is additionally linked to cognitive decline. Interestingly, structural neuroimaging studies have reported that hearing loss may precede or modulate the onset of cognitive impairment. In this study, we aimed to disentangle the effects of age, hearing loss, and tinnitus on gray matter structure. In total, 39 participants with hearing loss and tinnitus, 21 with hearing loss but without tinnitus, and 39 controls were included in this voxel- and surface-based morphometry MRI study. Whole brain volume and surface thickness measures were compared between the groups. Age-related gray matter volume decline was observed in all groups. Several brain areas showed smaller gray matter volume and cortical surface thickness in hearing loss without tinnitus, relative to controls. This reduction was observed both within and outside of the auditory pathway. Interestingly, these reductions were not observed in participants with tinnitus, who had similar hearing loss and were of similar age. Since we have tools to improve hearing loss, hearing screening may aid in the battle against cognitive decline.

 

This is really similar to the Taiwanese study stating similar things. The data is very limited and is quite questionable and the statements made in the analysis indicates that it may be an issue. It is interestingly also the case that there are people with tinnitus/hearing loss who also have no impact on their cognitive ability whatsoever too. Thus I would suggest that this study is not definitive in any manner.

 

Could you give me a link of that study?

 

Tinnitus and risk of Alzheimer’s and Parkinson’s disease: a retrospective nationwide population-based cohort study

 

It is disconcerting to read about cognitive decline and hearing loss, especially when my mother died from Alzheimer's. My father has hearing loss, but is doing very well cognitively at 80.

 

Interestingly, I know several people with extreme hearing loss (so much so they have an implant) and yet they tend to perform significantly above the norm cognitively.

Consequently, I am actually also wondering whether the research link between hearing loss and cognitive ability is actually as authoritative as the research work makes it out to be too.

 

I haven't read one yet that was able to exclude the risk factors for both (i.e. hypertension for instance is a risk factor for both hearing loss and dementia). So for now we can only say it's correlated and not necessarily causative.

 

My grandfather died in his 80s and had bad enough hearing loss in both ears. Cognitive ability was fine.

I agree with the point of correlation =/ causation.