Jaw-Opening Force as a Useful Index for Dysphagia: A Cross-Sectional and Multi-Institutional Study.

INTRODUCTION: Jaw-opening force (JOF) can be a potential screening tool for dysphagia. However, confounding variables such as comorbidities or physical and oral functions that are associated with the physiology of swallowing have not previously been examined. Adjusting for these variables could reveal the relationship between JOF and dysphagia and indicate whether JOF is an independent factor associated with dysphagia. We therefore aimed to assess the efficacy of using JOF for dysphagia screening in this multi-institutional study. METHODS: Community-dwelling older adults over the age of 65 years (N = 403) who visited the university dental hospitals and participated in health surveys (mean age ± standard deviation, 77.1 ± 7.0 years; range, 65-96 years) between November 2018 and January 2020 were included in this study. The JOFs of all participants were measured. The measured JOF was compared with the presence of dysphagia, which was defined using the Functional Oral Intake Scale and the Eating Assessment Tool-10. RESULTS: Multiple logistic regression analysis revealed that the presence of dysphagia was independently associated with JOF, calf circumference, and dependence after adjusting for age and sex. DISCUSSION/CONCLUSION: Decreased JOF can be a risk factor for dysphagia in older adults.

Association of aging and tooth loss with masseter muscle characteristics: an ultrasonographic study.

OBJECTIVES: This study aimed to investigate the relationship between aging and tooth loss on masseter muscle quantity and quality. MATERIALS AND METHODS: This cross-sectional study was conducted among 112 participants (in their 20s to 90s) who were independent in activities of daily living and were able to follow verbal commands. Exclusion criteria comprised participants with a lack of molar occlusal support, diseases that could affect muscle function, or temporomandibular disorder. Age, tooth loss, and weight were documented, and masseter muscle thickness (MMT) and masseter muscle echo intensity (MMEI) were measured using an ultrasonic diagnostic apparatus. A multiple regression analysis was used to determine the relationship between MMT, MMEI, aging, and tooth loss, among each sex. The significance level in the statistical analysis was p < 0.05. RESULTS: In males, aging was a significant explanatory variable for MMT (adjusted R2 = 0.27), while both aging and weight were significantly associated with MMEI (adjusted R2 = 0.54). In females, tooth loss and aging were significant explanatory variables for MMT (adjusted R2 = 0.36) and MMEI (adjusted R2 = 0.5), respectively. In both men and women, MMT and MMEI were highly correlated. CONCLUSIONS: Masseter muscles in males were more likely to be attenuated by aging than in females. The main attenuation factors were observed to differ between MMT and MMEI in women. CLINICAL RELEVANCE: In females, preservation of the natural dentition or prosthetic treatment may be effective for maintaining masseter muscle characteristics. In males, additional approaches, such as resistance exercise training, may be necessary.

Association between myotonometric measurement of masseter muscle stiffness and maximum bite force in healthy elders.

BACKGROUND: Maximum bite force (MBF) is a common and useful index of masticatory function; it correlates with physical strength in elderly people. Palpation of stiffness in the masseter muscle during forceful biting has been considered to be associated with MBF. However, this assessment method relies on subjective judgments; no study has verified the relationship between MBF and quantitative measurements of masseter muscle stiffness (MMS). OBJECTIVE: We aimed to verify the association between masseter muscle myotonometric assessment results and MBF. METHODS: In total, 117 community-dwelling >65-year-old individuals from the Tokyo metropolitan area were assessed. MMS on the dominant side during forceful biting was measured with a MyotonPRO device. Masseter muscle thickness (MMT) during rest and forceful biting was measured with an ultrasonic diagnostic apparatus, and the difference in MMT (DMMT) between the rest and forceful biting conditions was determined. MBF data were obtained with a pressure-sensitive sheet and an associated device. To determine the independent variables affecting MBF and MMS, multivariate linear regression analyses with adjustments for age, sex and number of teeth were performed. RESULTS: The multivariate analysis revealed that MBF correlated with the number of teeth (ß = .489, P < .001) and MMS (ß = .259, P = .003) (R2  = .433). MMS correlated with MBF (ß = .308, P = .003) and DMMT (ß = .430, P < .001) (R2  = .326). CONCLUSION: Masseter muscle stiffness possibly reflects a force generated by the masseter muscle during forceful biting. Therefore, MMS is effective to assess tooth loss as well as an index of masseter muscle strength when evaluating MBF.

Relationship between displacement of the masseter muscle during biting and masseter muscle quality and bite force in healthy elderly persons.

BACKGROUND: Although age-related changes in muscle quality influence muscle strength, the relationship between masseter muscle (MM) quality and maximum biting force (MBF) has never been studied. OBJECTIVE: The aims of the study were to verify the relationship among MM quality, MBF, and the displacement of the MM while biting forcefully (MMD) and to clarify the age-related decline in MBF in healthy elderly persons. METHODS: Seventy-four healthy community-dwelling individuals (mean age, >65 years) from Tokyo metropolis were recruited. The thickness (index of muscle quantity), echo intensity (index of muscle quality) and displacement of the MM while biting forcefully (MMT, MMEI and MMD, respectively) were measured by ultrasonography. MBF was measured using a pressure-sensitive sheet. Independent predictors of MBF and MMD were determined using multivariate linear regression analyses adjusted for age, sex and the number of present teeth. RESULTS: MBF was significantly correlated with the number of teeth (ß = 0.577, P < .001) and MMD (ß = 0.302, P = .015), but not with MMT (ß = 0.019, P = .868) or MMEI (ß = 0.054 P = .703). MMD was significantly correlated with MMEI (ß = -0.606, P < .001), but not with MMT (ß = 0.048, P = .681) or the number of teeth (ß = 0.065, P = .613). CONCLUSIONS: MMEI was associated with MMD, an index of MBF, regardless of tooth number. The age-related quality change in the MM might cause a decrease in its contraction, resulting in age-related decline in MBF.

Calf Circumference Is a Useful Index for Assessing Dysphagia among Community Dwelling Elderly Recipients of Long-Term Care.

Dysphagia is a common problem among older adults, causing aspiration pneumonia and malnutrition. It has been reported that calf circumference (CC), an index of nutritional status and physical activity, correlated with dysphagia in acute care hospitals, suggesting that CC can be a useful index for assessing dysphagia. We therefore aimed to explore the association between dysphagia and CC among community elderly people who require long-term care and determined the optimal CC cut-off value for patients with dysphagia. Our cross-sectional study, conducted at Tokyo Metropolis, included 154 participants (65 men) aged > 65 years (mean age: 80.1 ± 7.1) who required long-term care and were examined for dental disease and dysphagia during home visiting treatment. Age, body mass index (BMI), mini-nutritional assessment short-form (MNA-SF) score, Barthel index (BI), CC, functional oral intake scale (FOIS), and dysphagia severity scale (DSS) were evaluated. A DSS score < 5 was defined as dysphagia. To determine the association between CC and dysphagia, we performed logistic regression analysis and calculated the CC cut-off value for dysphagia. Thirty-seven participants (24.0%) were diagnosed with dysphagia. The logistic regression analysis showed that the presence of dysphagia was independently associated with CC after adjusting for age and sex. The CC cut-off value for the presence of dysphagia was 31.0 cm in men (sensitivity, 0.818; specificity, 0.868) and 29.3 cm in women (sensitivity, 0.760; specificity, 0.859). CC is a useful index for assessing dysphagia among community dwelling individuals who require long-term care.

Relationship between the jaw-closing force and dietary form in older adults without occlusal support requiring nursing care.

In clinical practice, we encounter cases wherein older adults lacking occlusal support consume foods requiring mastication and adequate swallowing function. This study investigated the relationship between jaw-closing force (JCF) and dietary form in older adults without occlusal support requiring nursing care. This prospective cross-sectional study included 123 older adults requiring nursing care who lost their molar occlusal support and consumed food orally without dentures. JCF was defined as the force required for crushing food with the edentulous ridges or with the tooth and edentulous ridge while closing the mouth. Participants were classified into four groups based on the International Dysphagia Diet Standardization Initiative framework for recommended dietary forms. Basic information was collected, and tongue pressure and JCF were measured. Differences in JCF were analyzed using one-way analysis of variance, while factors related to dietary form were evaluated using ordinal logistic regression analysis. Significant differences in JCF were observed among the four groups. Factors such as the Barthel Index, tongue pressure, and JCF were dietary form-related. Our findings suggest that older adults requiring nursing care tend to have higher JCF when consuming meals requiring mastication. Therefore, JCF could serve as an index for determining appropriate dietary forms in this population.

Effects of tongue right positioner use on tongue pressure: a pilot study.

The effectiveness of the tongue right positioner (TRP) use on oral and swallowing functions remains unclear. To investigate the effects of TRP use on tongue function in patients with dysphagia. This interventional study included eight participants with dysphagia who visited a university dental hospital. The measurement variables included tongue pressure (TP) as the primary outcome and lip and tongue movements, peak nasal inspiratory flow, and changes in the tongue and suprahyoid muscle regions on ultrasonography as the secondary outcomes. Each participant was asked to use a TRP for at least 8 h every night for 2 months. The measurement variables before and after the intervention were compared using the paired t test and Wilcoxon signed-rank test. TP after intervention (31.5 ± 13.1 kPa) was significantly higher than that before intervention (23.0 ± 13.4 kPa), while other measurement variables did not significantly improve. Numerous exercises have been suggested to improve TP; however, most require patients' adherence to instructions. In contrast, although participants did not perform active exercises, most participants in this study observed an improved TP. Our findings show that TRP can greatly improve TP after 2 months of usage.Trial registration number: University Hospital Medical Information Network Clinical Trials Registry (UMIN000040253, date of first registration: 27/04/2020).

Association between Tongue Pressure and Jaw-Opening Force in Older Adults.

Tongue pressure (TP) is used to assess tongue muscle strength and is related to function and frailty. While performing TP, it is necessary to elevate the tongue and oral floor by contracting the suprahyoid muscles. However, the association between TP and suprahyoid muscle strength remains unclear. Accordingly, this study investigated the relationship between TP and jaw-opening force (JOF), an indicator of suprahyoid muscle strength. This cross-sectional study included 88 independent community-dwelling participants aged ≥65 years. Age, sex, and the number of remaining teeth were recorded. Ultrasonography was used to evaluate the cross-sectional area of the tongue and geniohyoid muscle, as representatives of the suprahyoid muscles. Sarcopenia was diagnosed based on appendicular skeletal muscle mass index, handgrip strength, and gait speed. Multiple regression analysis was performed with TP as the dependent variable. TP was significantly associated with JOF (ß = 0.371, p = 0.003). This study revealed that decreased TP was associated with a decline in JOF and suprahyoid muscle mass in older adults. Thus, low TP may be associated with decreased JOF. Prevention of the weakness of the suprahyoid muscles and maintaining TP may also contribute to the prevention of frailty associated with TP.

Strength and morphology of a suprahyoid muscle and their relationship to forward head posture in healthy older adults.

AIM: Forward head posture, an abnormality in head and trunk positioning, adversely affects suprahyoid muscle activity. Jaw-opening force, which reflects suprahyoid muscle strength, is a useful index of dysphagia. However, the relationship between forward head posture and strength and morphology of suprahyoid muscles remains unclear. This study aims to clarify the relationship between forward head posture, jaw-opening force and morphology of suprahyoid muscles. METHODS: During October 2018, we enrolled older adults aged ≥65 years. The craniovertebral angle was measured, and an angle <49° was defined as forward head posture. Jaw-opening force was also measured. The geniohyoid muscle (GHM) was selected to represent the suprahyoid muscles, and its cross-sectional area and length were measured using ultrasonography. Sarcopenia was also determined based on the criteria of the 2019 Asian Working Group for Sarcopenia. Multiple regression analyses were conducted to determine the association between morphological characteristics of the suprahyoid muscle and jaw-opening force as well as the association between the former and forward head posture. RESULTS: Data of 87 participants were analyzed. Sex, cross-sectional area and length of the GHM, and sarcopenia were significantly associated with jaw-opening force. In addition, sex and forward head posture were significantly associated with the length of the GHM. CONCLUSIONS: Our study demonstrated that an overextended length of suprahyoid muscles mediates the relationship between forward head posture and jaw-opening force. Forward head posture is easily visualized and can be a useful indicator of decline in suprahyoid muscle strength. Geriatr Gerontol Int 2022; 22: 779-784.

Can Videofluoroscopic Swallowing Kinematic Analysis Predict Recovery of Oral Intake in Postoperative Oral Cancer Patients Requiring Nasogastric Tube Feeding?

This retrospective study determined the significant predictive factors for the number of days required to remove nasogastric tubes (NGTs) after surgery in patients with oral cancer (OC). In this study, patients underwent a videofluoroscopic swallowing study (VFSS) approximately 2 weeks after surgery. Videofluoroscopic images were analyzed, and variables such as swallowing and swallowing kinematics were measured. Patient characteristics, swallowing kinematics, and swallowing results were assessed using a Cox proportional hazards model. This study assessed 129 participants (66 men, 63 women, mean age: 69.0 ± 14.1 years) with nine types of cancer. The Cox proportional hazard ratio revealed that sex, body mass index before surgery, radiotherapy and/or chemotherapy, dysphagia before surgery, normalized pharyngeal constriction ratio, upper esophageal sphincter (UES) opening, and laryngeal vestibule disclosure (LVC) disorder were predictive factors for the removal of NGTs when adjusted for age. The study identified several predictive factors for the removal of NGTs and oral intake recovery in patients with OC. Regarding swallowing kinematics, UES opening is the most significant predictive factor. After surgery for OC, VFSS should be performed to assess safe eating methods and predict the recovery of oral intake and removal of the NGT.

Tongue-pressure resistance training improves tongue and suprahyoid muscle functions simultaneously.

PURPOSE: Producing tongue pressure (TP) by pushing the tongue against the palate consists of lifting the tongue muscles and elevating the floor of the mouth via suprahyoid muscle contraction. Though studies have shown that tongue-pressure resistance training (TPRT) increases tongue function, none have focused on suprahyoid muscle function enhancements. Our study aimed to verify whether TPRT improves both tongue function and hyoid movement during swallowing. MATERIALS AND METHODS: Eighteen patients (mean age: 76.8±6.2 years) with presbyphagia presenting with symptoms such as coughing and choking were enrolled. All patients performed daily living activities independently. None of the participants had diseases causing dysphagia or previous oral or pharyngeal surgery. Participants were instructed to push their tongues against the palate as hard as possible with their mouths closed for 10 seconds, and then resting for 10 seconds. A set consisted of five consecutive exercise and resting periods; two sets per day were performed for a month. TP and the oral diadochokinetic rate (ODKR), measured by repetitions of the syllables /ta/ and /ka/, assessed tongue function. The extent of anterior and superior hyoid movement and parameters related to swallowing, including the penetration aspiration scale (PAS) and the normalized residue ratio scale (NRRS) in the valleculae (NRRSv) and piriform sinus (NRRSp), were evaluated based on videofluoroscopic data. RESULTS: The anterior (P=0.031) and superior hyoid movement (P=0.012), TP (P=0.002), ODKR/ta/ (P=0.034), ODKR/ka/ (P=0.009), and the width of the upper esophageal sphincter (P=0.001) were larger at follow-up than at baseline. NRRSp (P=0.022), PAS (P=0.016), and pharyngeal transit times (P=0.004) were smaller at follow-up than at baseline. CONCLUSION: TPRT improved tongue strength, dexterity, both anterior and superior hyoid elevation, and swallowing functions. Therefore, TPRT could improve tongue function and suprahyoid muscle function simultaneously and contribute to prevention of sarcopenic dysphagia.