Koichiro Matsuo

Matsumoto Dental University · Department of Special Diagnostics

Objectives The deterioration of oral function to a state of oral hypofunction (OHF) has been associated with malnutrition and frailty. This cross-sectional pilot study investigated for differences in OHF prevalence and its category measures across age groups and sex, as well as their associations with physical function. Methods A total of 155 heal...

Objectives The deterioration of oral function to a state of oral hypofunction (OHF) has been associated with malnutrition and frailty. This cross-sectional pilot study investigated for differences in OHF prevalence and its category measures across age groups and sex, as well as their associations with physical function. Methods A total of 155 heal...

Introduction Oral hypofunction comprises seven aspects of oral condition, including oral hygiene, oral dryness, bite strength, tongue‐lip motor function, tongue pressure, masticatory function, and swallowing function. Each of these seven has a single diagnostic criterion; however, the use of a single indicator without consideration of sex, age, or...

Background The association between oral food intake and oral function during the subacute stage of stroke is not well known. Objective To investigate (1) oral function changes in subacute stroke patients and (2) association between oral function and oral intake status at several time points. Methods In a prospective study involving 324 stroke pat...

Objective: During the mastication of solid food, the tongue pushes the bolus laterally to place it onto occlusal surfaces as the jaw is opened. This movement is referred to as tongue-pushing (TP). TP has an important role in efficient chewing, but its kinematic mechanisms remain unclear. The present study quantified the kinematics of TP and its co...

Objectives: To investigate the changes in oral health status with dental intervention during the acute and subacute stages of stroke and their associations with oral intake status. Background: Oral health may deteriorate easily in patients following a stroke. However, data are scarce on the changes in oral health with dental intervention through...

Objectives Preserving sufficient oral function and maintaining adequate nutrition are essential for preventing physical frailty and the following long-term care. We recently developed the 6-month Comprehensive Awareness Modification of Mouth, Chewing And Meal (CAMCAM) program, in which participants gather monthly to learn about oral health and nutr...

The environments of nursing home staff and residents have dramatically changed since the onset of the COVID-19 pandemic, with greater demand for infection control. This study aimed to clarify the changes and regional differences in the surrounding environment of nursing home residents as well as the working environment of staff, including oral heal...

Objectives Preserving sufficient oral function and maintaining adequate nutrition are essential for preventing frailty and the following long-term care. We recently developed the 6-month Comprehensive Awareness Modification of Mouth, Chewing And Meal (CAMCAM) program, in which participants gather monthly to learn about oral health and nutrition whi...

Background: Stroke patients often suffer from dysphagia during their recovery. We hypothesised that subacute stroke patients with dysphagia had more deteriorated oral health status including muscle strength and motor function. Objective: Quantitatively investigate oral health status and identify associations with oral feeding status in stroke pa...

Objective To measure the occlusal force in the same group of patients with the Dental Prescale 50H type R and the Dental Prescale II, examine the association between them, and determine the reference value for Dental Prescale II that corresponds to the 50H type R 200 N reference value used to make a diagnosis of oral hypofunction. Background Reduc...

The deterioration of oral function to a state of oral hypofunction (OHF) is reportedly associated with malnutrition and frailty. Thus, we Investigated the association of OHF with physical characteristics and function and test the effects of a programme including comprehensive oral and physical exercises and textured lunch gatherings (COPE‐TeL progr...

Objectives ： When normal subjects eat solid food，the bolus is formed in the oropharynx prior to swallowing．When subjects chew liquid or a mixture of solid and liquid before swallowing，liquid frequently enters the hypopharynx before swallow onset．The purpose of this study was to determine whether transport to the hypopharynx is due to muscle activit...

The purposes of this human study using high-resolution manometry were to verify whether the swallowing reflex can be evoked by intra-esophageal fluid injection and whether the reflex latency and manometric variables differ depending on the injected location, amount, or speed. Ten healthy individuals participated in this study. The tip of the intran...

Background Swallowing disorder or dysphagia is quite common in hospitalized patients. Using Fiberoptic Endoscopic Evaluation of Swallowing (FEES) is one of the clinical standards for evaluating swallowing disorder to prevent serious consequences such as aspiration pneumonia. Objectives This study aimed to determine the prevalence and the associate...

Kikumura K, Kagaya H, Shibata S, Matsuo K, Toda F, Ogawa M, Ito Y, Ozeki M, Otaka Y. Value of the Hyodo score in predicting dysphagia severity, recommended diet, and liquid consistency. Jpn J Compr Rehabil Sci 2020; 11: 109-115. Objective: To define whether the Hyodo score can be used to predict dysphagia severity and determine the appropriate diet...

Background: Preserving sufficient oral function and maintaining proper nutrition are essential to prevent frailty. Thus, we have developed "munchy" foods that contain harder textures and are rich in protein. Objectives: This study aimed to test the effects of masticating textured foods on masticatory muscle activity in young and older adults. M...

Perioperative oral care can reduce the risk of postoperative infections. This study examined 1) changes in oral bacteria counts during the perioperative period and 2) differences in bacteria counts in patients with or without endotracheal intubation. 47 patients who visited our hospital dental clinic prior to cardiac valve surgery were prospectivel...

Objectives: Oral infection control is important for patients undergoing cardiac valve replacement (CVR) as prophylaxis for postoperative complications. This study examined the changes in oral health status by preoperative periodontal treatment and its effects on postsurgical complications in CVR patients. Material and methods: We recruited 64 pa...

Objectives Proper nutrition and physical exercises are essential to prevent frailty in older adults. Proper masticatory performance and oral function may influence on physical activities as well since the mouth is the entrance of nutrition and digestion. Thus, the present study aimed to test the combined program of specially devised lunch gathering...

Background and aims: Systemic muscle wasting during perioperative periods has a major impact on postoperative morbidity. However, data on oropharyngeal muscle weakness after surgery are scarce. We examined whether maximum tongue pressure (MTP) and hand grip strength (HGS) diminished during the perioperative period without and with oral feeding in...

Background There is growing international interest in identifying the effects of ageing on oral health and on appropriate strategies for managing oral disorders. The Japanese Society of Gerodontology (JSG), as the official representative of researchers and clinicians interested in geriatric dentistry in Japan, makes several recommendations on the c...

This chapter will describe the human swallowing in comparison with other mammals.

This chapter presents three case studies for a more comprehensive understanding of assessment and treatment of dysphagia and discusses common etiologies.

Dysphagia is a common problem in medical situations. Many disease processes are associated with a high incidence of dysphagia. Individuals with dysphagia may have multiple problems and need assessment and treatment that requires the input of multiple health professional specialists. Good team approach will increase the efficacy of dysphagia treatme...

People with dysphagia are at a greater risk of poor oral hygiene and health. Dried secretion accumulated in oral cavity reduces oral sensitivity and promote bacterial growth. Aspiration of these pathogens can lead to life-threatening respiratory disorders and pulmonary infection. Oral care is therefore important issue from the perspective of preven...

This chapter discusses common dysphagia terminology. A common understanding of important terms relevant to dysphagia enables healthcare professionals to communicate clearly and rapidly. The basic knowledge of anatomical structures associated with swallowing is fundamental to understanding the whole swallow process including the evaluation and treat...

Swallowing is a complex activity in humans that involves coordinated activity of the mouth, pharynx, larynx, and esophagus. Thorough knowledge of these physiological processes is necessary to understand the complexity of swallowing and serves as an essential module for explaining the fundamental mechanisms that operate in swallowing activity. In ad...

Before describing the swallowing exercises in this chapter, we first address the principle of such exercises. This fundamental knowledge provides a comprehensive understanding of the term “exercise” and the techniques by which to achieve effective treatment outcomes. The swallowing exercise-based treatment will be described based upon the principle...

Clinical evaluation, both instrumental and noninstrumental, plays an important role in the swallowing assessment of the patients with dysphagia. The gathered information from thorough evaluation contributes the presence of dysphagia, dysphagia severity level, rehabilitation planning, and both the problem and the potential solution. The dysphagia sc...

In addition to several methods of swallowing exercise widely used to improve swallowing function, the alternative treatment by using assistive device and surgical intervention are viable options to achieve the treatment outcome, for safety and for improved quality of life. The common devices and surgical techniques commonly used in our practice are...

Shibata S, Kagaya H, Tanaka S, Fujii W, Nakagawa K, Matsuo K, Abe K, Ishibashi N, Inamoto Y, Saitoh E. Efficacy of a novel training food based on the process model of feeding for mastication and swallowing: A study among dysphagia patients. Jpn J Compr Rehabil Sci 2017; 8: 82-87. Objective: Our goal was to verify the validity and safety of chew-swa...

Aim: When eating food that contains both liquid and solid phases, the liquid component frequently enters the hypopharynx before swallowing and can increase the risk of aspiration. Thus, we examined whether the initial viscosity of mixed consistency food could alter pre-swallow food transport and breathing-swallowing coordination in older adults....

Purpose：The effects of various oral functions on nutritional status and general conditions are not well elucidated, especially in frail or dependent elderly individuals. Thus, in the present study, we investigated the associations and relationships between deterioration of oral functions and malnutrition in hospitalized frail elderly patients. Meth...

Nakagawa K, Matsuo K, Shibata S, Inamoto Y, Ito Y, Abe K, Ishibashi N, Fujii W, Saitoh E. Efficacy of a novel training food based on the process model of feeding for mastication and swallowing ― a preliminary study in elderly individuals living at a residential facility ―. Jpn J Compr Rehabil Sci 2014; 5: 72-78. Purpose: We examined the validity an...

When eating solid food, the tongue intermittently propels triturated food to the oropharynx or valleculae, where a bolus accumulates before swallowing. The tongue motion during this food transport (stage II transport, STII) is distinctly different from that during chewing, and is more similar to the oral propulsive stage of swallowing. Therefore, w...

Few studies have reported the activation sequence of the swallowing muscles in healthy human participants. We examined temporal characteristics of selected hyoid muscles using fine wire intramuscular electromyography (EMG). Thirteen healthy adults were studied using EMG of the anterior belly of digastric (ABD), geniohyoid (GH), sternohyoid (SH), an...

Stage II transport (St2Tr) is propulsion of triturated food into the pharynx for storage before swallowing via tongue squeeze-back against the palate. To clarify the phenomenology of St2Tr, we examined the effects of food consistency and the number of chewing cycles on the number of St2Tr cycles in a chew-swallow sequence. We recorded chew-swallow...

We examined the temporospatial characteristics of stage I oral food transport, in which a piece of solid food is moved from the anterior oral cavity to the postcanine region for chewing. Anteroposterior transport is accomplished by carrying food posteriorly on the surface of the tongue, in contrast to the squeeze-back mechanism of stage II transpor...

When chewing solid food, part of the bolus is propelled into the oropharynx before swallowing; this is named stage II transport (St2Tr). However, the tongue movement patterns that comprise St2Tr remain unclear. We investigated coronal jaw and tongue movements using videofluorography. Fourteen healthy young adults ate 6 g each of banana, cookie, and...

Objective: To determine the causative factor behind the formation of membranous substances in the mouths of elderly patients requiring nursing care. Background: Membranous substances are sometimes observed in the mouths of elderly persons requiring nursing care, and these can lead to bleeding, infection and asphyxiation. Materials and methods:...

Objectives Rubber dams increase the quality and safety of dental treatment. However, the condition of a rubber dam over an open mouth may also obstruct the route for respiration. We tested whether an open mouth with or without a rubber dam would affect upper airway patency and breathing pattern. Materials and methods Twenty young healthy volunteers...

When eating food containing both liquid and solid phases (two-phase food), the liquid component frequently enters the hypopharynx before swallowing, which may increase the risk of aspiration. We therefore tested whether preswallow bolus transport and swallow initiation would change as the viscosity of two-phase food was increased. Fiberoptic endosc...

Objectives: When eating solid food, the food bolus is aggregated in the oropharynx until swallow onset. During eating of food containing liquid with solid (two-phase food), the liquid component frequently enters the hypopharynx before swallowing. We tested whether increased liquid viscosity in two-phase food would change pre-swallow bolus transport...

Tongue movement is temporo-spatially coordinated with jaw and hyoid movements during eating and speech. As such, we evaluated: (1) the correlation between the tongue with jaw and hyoid movements during eating and speech and (2) the relative influence of the jaw and hyoid on determining tongue movement. Lateral projection videofluorography was recor...

The pathways for air and food cross in the pharynx. In breathing, air may flow through either the nose or the mouth, it always flows through the pharynx. During swallowing, the pharynx changes from an airway to a food channel. The pharynx is isolated from the nasal cavity and lower airway by velopharyngeal and laryngeal closure during the pharyngea...

We studied the usefulness of "eye closure", "loss of eyelash reflex", and "smooth insertion of bite block" to be considered as the optimum level of propofol sedation indicators for behavior management in uncooperative patients with disabilities. The subjects were 16 patients with Down's syndrome, autism or mental retardation who needed intravenous...

Eating and swallowing are complex behaviors involving volitional and reflexive activities of more than 30 nerves and muscles. They have two crucial biologic features: food passage from the oral cavity to stomach and airway protection. The swallowing process is commonly divided into oral, pharyngeal, and esophageal stages, according to the location...

This study explored potential factors in elderly requiring care that cause dryness of the dorsum of the tongue despite moisture retention in the sublingual mucosa. Subjects were 224 elderly (mean age: 83.6 +/- 7.4 years) living in a nursing home and requiring individual care. Measurement of moisture of the dorsum of the tongue and sublingual mucosa...

During feeding, solid food is chewed and propelled to the oropharynx, where the bolus gradually aggregates while the larynx remains open and breathing continues. The aggregated bolus in the valleculae is exposed to respiratory airflow, yet aspiration is rare in healthy individuals. The mechanism for preventing aspiration during bolus aggregation is...

The "chin-down" or "chin-tuck" maneuver is a postural technique widely used in dysphagia treatment. The posture, however, does not have a precise anatomical definition. We studied the current practice of 42 speech-language pathologists (SLPs) in Japan and the U.S. with a questionnaire survey regarding the chin-down posture. The main findings were t...

When healthy individuals eat solid food, chewed food is usually transported to the oropharynx where it accumulates before swallowing (stage II transport). We tested the hypothesis that this transport process can be altered by volition. Eight healthy young subjects ate 8 g pieces of cookie with barium while movements were recorded with videofluorogr...

Preswallow bolus formation usually occurs in the mouth for liquids and in the oropharynx for solid foods. We examined the effect of chewing on the relationship between bolus transport and swallow initiation. Fifteen healthy subjects were imaged with lateral projection videofluorography while eating liquids, solid foods, and a mixture of liquid and...

咀嚼嚥下の評価法の確立のため,健常成人10名を対象として,4食物条件下で咀嚼が嚥下反射開始前の食塊位置および嚥下時間経過に及ぼす影響を嚥下造影検査を用いて検討した.液体命令嚥下に比し全咀嚼条件で食塊先端位置の中～下咽頭への到達率が高く,食塊進入には咀嚼の存在が一義的に関与し,食物形態はそれを修飾する役割を担うと思われた.混合咀嚼条件では食塊は全例で嚥下前に中～下咽頭へ到達しており,信頼性の高い負荷法といえた.液体を含む咀嚼嚥下では,下咽頭到達が高率で下咽頭通過時間も長く,誤嚥防止の観点から興味深い所見であった.咀嚼嚥下は命令嚥下とは別様式であり「食べる」機能の評価と位置づけられた.