Improvement of brain metabolism and cognitive function after cochlear implantation in profoundly deafeaned elderly patients

2021 Fiscal Year Final Research Report

• Project/Area Number: 18K09392
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 56050:Otorhinolaryngology-related
• Research Institution: Kobe City Medical Center General Hospital(First Clinical Division, Second Clinical Division, Third
• Principal Investigator: Naito Yasushi 地方独立行政法人神戸市民病院機構神戸市立医療センター中央市民病院(第1診療部、第2診療部、第3診療部, 中央市民病院, 参事 (70217628)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Keywords: 高齢者 / 高度難聴 / 脳代謝 / PET / 人工内耳

Outline of Final Research Achievements

Brain metabolism was measured using FDG-PET in elderly patients with profound hearing loss who met the criteria for cochlear implantation. In elderly patients with profound deafness without cochlear implants, hypometabolic areas were observed in the parietal and dorsal frontal lobes as well as in the temporal cortex. On the other hand, in the elderly patients who had been using cochlear implants for more than one year, hypometabolism was observed in the anterior half of the superior temporal gyrus and part of the dorsal frontal lobe, but the difference from normal hearing subjects was smaller than in the patients with no cochlear implants. The results suggest that the effects of profound hearing loss in the elderly on brain metabolism are more extensive than just in the auditory cortex. In addition, auditory compensation with cochlear implants may reduce the decline of brain function due to profound deafness, but these issues need to be verified in a larger number of cases.

Free Research Field

耳鼻咽喉科学

Academic Significance and Societal Importance of the Research Achievements

近年、加齢性の難聴は聴覚や言語聴取の低下だけでなく認知機能低下のリスクを高めることが報告されており、その機序について種々の説が挙げられているが、いまだ詳細は明らかになっていない。本研究成果の学術的意義は、高度難聴が高齢者の脳の糖代謝を低下させることと、聴覚補償でそれを軽減させる可能性を初めて示した点にある。難聴は補正可能な認知症の危険因子の中で最大のものとされており、聴覚検査と脳代謝計測で難聴と脳機能の関係を定量的に明らかにし、高齢者の認知症予防について具体的な方向を示した点で本研究成果の社会的意義は大きいと考える。