研究者業績

中川 誠司

Nakagawa Seiji  (Seiji NAKAGAWA)

基本情報

所属
千葉大学 フロンティア医工学センター 教授
(兼任)大学院 工学研究院 教授
(兼任)大学院 融合理工学府 基幹工学専攻 医工学コース 教授,コース長
(兼任)工学部 総合工学科 医工学コース 教授,コース長
(兼任)医学部附属病院 教授
国立研究開発法人 産業技術総合研究所 客員研究員
東京大学 大学院医学系研究科 客員研究員
Univ. of Washington Visiting Scholar
国立研究開発法人 量子科学技術研究開発機構 客員研究員
学位
博士(工学)(1999年3月 東京大学)

連絡先
s.nakagawa99.alumni.u-tokyo.ac.jp
J-GLOBAL ID
200901063867675418
researchmap会員ID
5000005804

外部リンク

非侵襲的手法による神経生理計測(特に脳機能計測),心理計測,物理計測,さらにはコンピュータ・シミュレーションを駆使して,聴覚を中心とした知覚メカニズムや認知メカニズムの解明を進めています.また,知覚・認知メカニズム研究で得られた成果を利用することで,骨伝導補聴器や骨伝導スマートホンを初めとした福祉機器・医用機器の開発や,室内の視聴覚環境の最適化,騒音の快音化といった応用研究にも取り組んでいます.


論文

 312
  • Irwansyah, Sho Otsuka, Seiji Nakagawa
    Acoustical Science and Technology 2024年  
  • Irwansyah, Sho Otsuka, Seiji Nakagawa
    MethodsX 11 102394-102394 2023年12月  
    Bone conduction hearing aids (BCHAs) offer an alternative solution for individuals with outer or middle ear issues who cannot benefit from traditional air conduction hearing aids. However, the phenomenon of "crosstalk," where sound intended for one ear is mistakenly transmitted to the other ear through bone conduction, presents a challenge. This unintended transmission may limit the benefits of binaural hearing that can be achieved using two BCHAs, such as accurately detecting a sound source's direction. In this article, we present a method to suppress "crosstalk" within the human head using an adaptive algorithm to control two audiometric bone transducers. •Our method involves positioning an error sensor at a location considered close to the cochlea, such as the ear canal or the mastoid, and utilizing an adaptive algorithm to estimate the crosstalk compensation filter. This filter generates an anti-signal, which is then transmitted to one of the two transducers, effectively cancelling the crosstalk.•To verify whether the crosstalk cancellation reaches the cochlea in the inner ear, we provide a procedure for measuring hearing thresholds with and without crosstalk cancellation. This acts as a subjective measure of the efficacy of our crosstalk cancellation method. By leveraging an adaptive algorithm, this approach provides personalized cancellation and has the potential to enhance the performance of binaural BCHAs.
  • IRWANSYAH, Sho OTSUKA, Seiji NAKAGAWA
    INTER-NOISE and NOISE-CON Congress and Conference Proceedings 268(4) 4866-4873 2023年11月30日  
    This study aimed to address the issue of "crosstalk" in bone conduction hearing aids, where sound meant for one ear is mistakenly perceived by the other ear via bone conduction. We explored a potential solution by canceling the crosstalk sound at the cochlea. To achieve this, an accelerometer was placed on the mastoid to monitor the crosstalk sound produced by an audiometric bone transducer on the opposite side of the head, while a second transducer on the same side as the accelerometer was used to cancel it out. The filtered-x least mean square (FxLMS) algorithm was used to optimize the crosstalk compensation (CTC) filter for cancellation at the mastoid. Then, the subjects manually adjusted the filter coefficients through a lateralization task to achieve crosstalk cancellation at the cochlea. This task involved modifying phase and level differences between pure-tone sounds from the two transducers, making the sound seem to originate from the leftmost or rightmost side of the head. Our results indicated successful cancellation of crosstalk sound at the cochlea, as subjects' hearing thresholds under noise masking were lower with crosstalk cancellation.
  • Irwansyah Irwansyah, Sho Otsuka, Seiji Nakagawa
    超音波エレクトロニクスの基礎と応用に関するシンポジウム講演論文集 44 68 2023年11月13日  
  • Hajime Yano, Tetsuya Takiguchi, Seiji Nakagawa
    NeuroReport 35(1) 1-8 2023年10月30日  
    The impressions of heating, ventilation, and air conditioning (HVAC) sounds are important for the comfort people experience in their living spaces. Revealing neural substrates of the impressions induced by HVAC sounds can help to develop neurophysiological indices of the comfort of HVAC sounds. There have been numerous studies on the brain activities associated with the pleasantness of sounds, but few on the brain activities associated with the thermal impressions of HVAC sounds. Seven time-varying HVAC sounds were synthesized as stimuli using amplitude modulation. Six participants took part in subjective evaluation tests and MEG measurements. Subjective coolness of the HVAC sounds was measured using the paired comparison method. Magnetoencephalographic (MEG) measurements were carried out while participants listened to and compared the time-varying HVAC sounds. Time-frequency analysis and cluster-based analysis were performed on the MEG data. The subjective evaluation tests showed that the subjective coolness of the amplitude-modulated HVAC sounds was affected by the modulation frequency, and that there was individual difference in subjective coolness. A cluster-based analysis of the MEG data revealed that the brain activities of two participants significantly differed when they listened to cooler or less cool HVAC sounds. The frontal low-theta (4–5 Hz) and the temporal alpha (8–13 Hz) activities were observed. The frontal low-theta and the temporal alpha activities may be associated with the coolness of HVAC sound. This result suggests that the comfort level of HVAC sound can be evaluated and individually designed using neurophysiological measurements.

MISC

 985

書籍等出版物

 8

担当経験のある科目(授業)

 28

共同研究・競争的資金等の研究課題

 26

産業財産権

 75