Funding for this research was provided by:
Toho University (Project research 19-22)
Japanese Ministry of Education, Culture, Sports, Science and Technology (24300187, 24659397, 26460899, 15K122588, 15K15254, 15K01420, 15K11644, 19H03984, and 19K22821)
Japanese National Center for Geraitrics and Gerontology (25-7, 28-13)
Toho University Graduate School of Medicine (The Research Promotion Grant)
Japanese Society of Dysphagia Rehabilitation (Resaerch Grant)
Received: 16 May 2019
Accepted: 21 February 2020
First Online: 28 February 2020
Ethics approval and consent to participate
: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Declaration of Helsinki and its later amendments. The study protocol was approved by the Ethics Committee of Toho University Omori Medical Center (No. 27–279). Informed consent was obtained from all individual participants included in this retrospective study by the opt-out consent process.
: Not applicable.
: The authors declare that they have no competing interests.