Effects of transcranial electric stimulation on the auditory evoked magnetic fields elicited in noisy environments

2021 Fiscal Year Final Research Report

• Project/Area Number: 18K09327
• 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: International University of Health and Welfare
• Principal Investigator: Okamoto Hidehiko 国際医療福祉大学, 医学部, 教授 (30588512)
• Co-Investigator(Kenkyū-buntansha): 木田 哲夫 愛知県医療療育総合センター発達障害研究所, 障害システム研究部, 室長 (80419861)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Keywords: 雑音 / 聴性誘発反応 / 聴覚 / 聴覚時間分解能 / 脳波 / 脳磁図 / 経頭蓋電気刺激

Outline of Final Research Achievements

We externally applied a narrowband random transcranial electrical stimulation and immediately afterward measured auditory evoked fields elicited by the sound stimuli related to the electrical stimulation and those unrelated. The obtained magnetoencephalography data are currently being analyzed.
Since the magnetoencephalography had not been available due to the corona disaster, we conducted an additional electroencephalography study. We focused on auditory temporal resolution, which plays an important role in speech comprehension in noise environments. We measured auditory steady-state responses elicited by silent gaps embedded within a broadband noise at 40 Hz periods. The results showed that the durations of the silent gaps significantly affected the amplitudes and phases of the auditory steady-state responses. This result suggests that we can objectively measure auditory temporal resolution using electroencephalography.

Free Research Field

聴覚医学

Academic Significance and Societal Importance of the Research Achievements

本研究ではどれだけ時間的に細かく音信号を処理できるかを示す「聴覚時間分解能」を、脳波を用いて他覚的に計測できることを示した。聴覚時間分解能は会話音の聴き取りに重要な役割を果たしているが、これまでは本人の反応（ボタン押し等）が必要であった。本研究の方法を用いれば、小児や認知症患者でも聴覚時間分解能を測定することが可能である。他覚的に聴覚時間分解能を計測することで、聴覚障害の診断や治療に役立つと考える。