2023-11-21 カリフォルニア大学サンディエゴ校(UCSD)
Researchers are trying to understand the association between hearing loss and increased risk of dementia. Photo credit: iStock/image_jungle
◆カリフォルニア大学サンディエゴ校とカイザー・パーマネンテ・ワシントン保健研究所の研究者らは、聴力の低下が特定の脳領域の微細構造に影響を与える可能性を調査。研究によれば、聴力低下者は聴覚領域や言語処理に関与する前頭葉、実行機能領域で微細構造の違いが見られ、これが認知症リスクの増加に寄与する可能性が示唆されている。この結果から、認知努力を減少させる措置(字幕やキャプション、補聴器の使用など)が脳を保護し、認知症リスクを減少させるのに役立つ可能性があるとされています。
<関連情報>
- https://today.ucsd.edu/story/hearing-loss-is-associated-with-subtle-changes-in-the-brain
- https://content.iospress.com/articles/journal-of-alzheimers-disease/jad230767
純音閾値の上昇は聴覚処理と注意配分に関連する皮質領域の微細構造の変化と関連する
Elevated Pure Tone Thresholds Are Associated with Altered Microstructure in Cortical Areas Related to Auditory Processing and Attentional Allocation
McEvoy, Linda K. ;Bergstrom, Jaclyn;| Hagler Jr, Donald J.; Wing, David; Reas, Emilie T.
Journal of Alzheimer’s Disease Published: 21 November 2023
DOI: 10.3233/JAD-230767
Abstract: Background:Hearing loss is associated with cognitive decline and increased risk for Alzheimer’s disease, but the basis of this association is not understood. Objective:To determine whether hearing impairment is associated with advanced brain aging or altered microstructure in areas involved with auditory and cognitive processing. Methods:130 participants, (mean 76.4±7.3 years; 65% women) of the Rancho Bernardo Study of Healthy Aging had a screening audiogram in 2003–2005 and brain magnetic resonance imaging in 2014–2016. Hearing ability was defined as the average pure tone threshold (PTA) at 500, 1000, 2000, and 4000 Hz in the better-hearing ear. Brain-predicted age difference (Brain-pad) was calculated as the difference between brain-predicted age based on a validated structural imaging biomarker of brain age, and chronological age. Regional diffusion metrics in temporal and frontal cortex regions were obtained from diffusion-weighted MRIs. Linear regression analyses adjusted for age, gender, education, and health-related measures. Results:PTAs were not associated with brain-PAD (β= 0.09; 95% CI: –0.084 to 0.243; p = 0.34). PTAs were associated with reduced restricted diffusion and increased free water diffusion primarily in right hemisphere temporal and frontal areas (restricted diffusion: βs = –0.21 to –0.30; 95% CIs from –0.48 to –0.02; ps < 0.03; free water: βs = 0.18 to 0.26; 95% CIs 0.01 to 0.438; ps < 0.04). Conclusions:Hearing impairment is not associated with advanced brain aging but is associated with differences in brain regions involved with auditory processing and attentional control. It is thus possible that increased dementia risk associated with hearing impairment arises, in part, from compensatory brain changes that may decrease resilience.
