Div. of Dysphagia Rehabilitation

Professor　 INOUE Makoto

inoue@dent.niigata-uj.ac.jp

face

Our Education

　Geriatric Dentistry
　Dysphagia Rehabilitation

Our Research

We are performing research on eating behaviors, including chewing and swallowing.
In our human research, we are evaluating motor function related to mastication and swallowing with the goal of elucidating the mechanism of the functional interaction between the oral and pharyngeal/laryngeal regions. For this purpose, electrophysiological, kinematic, and image diagnostic methods such as electromyography, transcranial magnetic stimulation, motion capturing, and videofluoroscopic or videoendoscopic evaluation are utilized. Additionally, food engineering approaches such as analysis of food texture, consistency, and moisture content are utilized to evaluate the physical properties of the food bolus. Recent achievements include electromyographic measurements of swallowing-related muscles during tongue and mastication movements, changes in the swallowing-related area of the sensorimotor cortex associated with oral thermal stimulation, and the effects of changes in saliva secretion on mastication and swallowing movements. Furthermore, we have been focusing on industry–academia collaborations. In 2023, we collaborated with KAMEDA SEIKA Co., Ltd.; The Nisshin OilliO Group, Ltd.; and MTG Co., Ltd.
In our animal research, we perform studies to elucidate the neural mechanisms of mastication and swallowing. We also conduct transrational studies using pathological animal models such as stroke and chronic obstructive pulmonary disease. Our research topics include verification of the functional relationship between mastication and swallowing, identification of peripheral receptors and central nervous circuits involved in swallowing evocation, evaluation of nerve and muscle activities in swallowing movements, and examination of developmental changes of masticatory function with different food forms. Our research methods include behavioral, electrophysiological, immunohistochemical, neuropharmacological, and biochemical approaches. Recent new findings include identifying the posterior belly of the digastric muscle as a swallowing-related muscle, understanding the modulation of the jaw reflex during mastication and swallowing, elucidating the facilitation effect of anticholinergic drugs that induce xerostomia on water-evoked swallowing, and determining the　 mechanism of initiation of swallowing via adenosine triphosphate-sensitive potassium channels.
We would like to provide evidence of the importance of oral function for ingestion and increase the presence of dentistry in dysphagia rehabilitation. This may help to establish a new foundation for future clinical practice.
Figure 1. A representative data of electromyograms of masseter, suprahyoid, and tongue muscles during chewing, bolus formation, bolus transport and swallowing.
Figure 2. The posterior belly of the digastric muscle was revealed to be a swallowing-related muscle in which motoneurons receive inputs from the swallowing central pattern generator. Electromyographic recordings also revealed the swallowing activity of this muscle.
Figure 3. Potassium chloride solution induced the swallowing reflex more times than saline or water administration. Because this was also evident from peripheral nerve responses, we clarified the expression of related receptors.

Clinical Fields

Dysphagia Rehabilitation
The clinical approaches to dysphagia rehabilitation include assessment, diagnosis, and rehabilitation for patients with dysphagia following cerebrovascular disorders, postoperative head and neck cancer and esophageal cancer, and neuromuscular disease. The numbers of new inpatients and outpatients have been increasing each year, and the diseases and pathologies that cause dysphagia have been becoming more diverse and complex, especially in aged patients. On such a background, it is essential to support these patients by multidisciplinary collaboration (e.g., conferences with attending physicians, rehabilitation physicians, therapists, nurses, and registered dietitians). Because our department mainly consists of dentists, dental hygienists, and speech-language pathologists, we are able to provide optimal medical care and rehabilitation that emphasizes oral function in dysphagia rehabilitation in collaboration with a variety of professions.
Recent publications
1. Evaluation in the cause of impairments of bolus transport and epiglottis inversion (T. Suzuki et al. Dysphagia. 37(6):1858-1860. 2022)
2. The impact of oral function on regaining oral intake and adjusting diet forms for acute stroke patients (S. Kulvanich et al. J Stroke Cerebrovasc Dis.31(5):106401. 2022)

Oral Hypofunction
The clinical treatment of oral hypofunction has been covered by national health insurance since 2016, and an oral function assessment and management section was established in our medical and dental hospital in June 2018. The Department of Oral Rehabilitation has developed clinical approaches to evaluate, diagnose, and manage patients with oral hypofunction.
Recent publications
1. Survey of oral hypofunction in older outpatients at a dental hospital (W. Onuki et al. J Oral Rehabil. 48(10):1173-1182, 2021)
2. Effect of management on patients with oral hypofunction (W. Onuki et al. Gerodontology. 40(3):308-316, 2023).

Xerostomia/Taste Disorder
At the xerostomia clinic for the patients with xerostomia, we focus on accurately identifying the underlying causes of xerostomia, such as the side effects of drugs, stress, Sjogren’s syndrome, and post-radiation therapy. According to the assessment results, a comprehensive diagnosis is established and an appropriate clinical approach is undertaken. At the clinic of taste disorders, the potential causes of such disorders (e.g., zinc deficiency, side effects of drugs, and stress) are examined and diagnosed through taste tests and blood tests. Appropriate treatments are then provided.
Recent publications
1. The characteristics of medication-induced xerostomia and effect of treatment is recently reported (K. Ito et al. PLoS One. 12;18(1):e0280224, 2023)

Our Website

https://www5.dent.niigata-u.ac.jp/~dysphagia/index.html

Our Citizenship

1. Niigata Support Society of Dysphagia
Since 2009, we have managed the Niigata Support Society of Dysphagia to support patients with dysphagia through industry–academia collaborations, including companies that manufacture dysphagia food, nursing care tableware, and oral hygiene. As of December 2023, there were approximately 280 individual members, 18 company members, and 3 organizational members.
1) Academic meetings
We hold academic meetings twice a year with lecturers from various professions, including doctors, dentists, nurses, and registered dietitians. Since 2022, these meetings have been held in a hybrid format (both in-person and online), and participants from outside Niigata Prefecture are also accepted.
2) Food support stations
We manage a food support station in the amenity mall bus waiting room of Niigata University Medical and Dental Hospital. We provide a display of dysphagia food, nursing care tableware, and oral hygiene products as well as advice for food intake and swallowing.
3) Dysphagia seminars
Dysphagia seminars are held twice a month for general local residents in the Niigata University Medical and Dental Hospital Amenity Mall training room (FY2020-2023 is currently canceled because of the coronavirus pandemic).
Ref: https://www5.dent.niigata-u.ac.jp/~dysphagia/support/

2. Management of barrier-free lunch parties
This activity aims to provide children with dysphagia and their families the opportunity to enjoy eating out. Full-course meals are provided in five stages: regular meals, late meals, middle meals, early meals, and injection meals, and staff specializing in dysphagia provide meal assistance and advice. Since 2009, the Niigata Support Society of Dysphagia has been co-hosting the initiative of special needs schoolteachers in Niigata Prefecture, and our department has managed this initiative since 2023. In 2023, it received the Cabinet Office’s first “Children Who Create the Future Award.”
In future, we plan to foster the development of human resources such as chefs, nutritionists, and students, with the goal of increasing the number of restaurants where children with dysphagia can eat out.

3. Training course for private dentists to manage and treat elderly patients with dysphagia at home/nursing home
The number of elderly people in need of nursing care in Niigata continues to increase, and the aging rate was 33.6% in 2023 (significantly higher than the national average). Approximately 20% of all elderly people who require nursing care experience dysphagia, and 40% of them live at home. Because of a lack of awareness of dysphagia, appropriate management may not be provided. Against this background, we began to train private dentists in charge of dysphagia treatment in 2012. Since 2015, this project has been supported by the Niigata Dental Association.
Ref: https://www5.dent.niigata-u.ac.jp/~dysphagia/clinical/ve_doctor.html

4．Construction of home medical care system for elderly patients with dysphagia
We have constructed a home medical care system that provides guidance from universities (specialized physicians) to patients with dysphagia who have difficulty accessing medical resources and facilitates information coordination among related multidisciplinary professionals. First, a home clinician performs an eating and swallowing assessment and enters the information into a dedicated application. Doctors, nurses, dentists, speech therapists, and other professionals registered as a team can access this information. In addition, specialized physicians affiliated with universities provide advice regarding diagnosis and treatment.
In the future, we aim to develop and disseminate a telemedicine support application available throughout Japan.
Ref:https://www5.dent.niigata-u.ac.jp/~dysphagia/clinical/oishien.html

Research Figures

Back to index