Association between characteristics of swallowing-related muscles and trunk muscle mass.

Swallowing function is associated with systemic factors. Whether trunk or appendicular skeletal muscle mass is a better indicator of swallowing-related muscle characteristics in community-dwelling older adults is not clear. Hence, we investigated the association between the characteristics of swallowing-related muscles (e.g., mass and quality) and trunk muscle mass. Community-dwelling older adults aged ≥ 65 years (n = 141; men: n = 45, women: n = 96) were recruited for this cross-sectional observational study via a health survey conducted in 2018. Trunk muscle mass index (TMI) and appendicular skeletal muscle mass index (SMI) were measured using bioelectrical impedance analysis. Cross-sectional areas (CSAs) and echo intensity (EI) of the geniohyoid muscle (GHM) and tongue were evaluated using an ultrasonic diagnostic apparatus. Multiple regression analysis was used to examine the relationship of the characteristics of swallowing-related muscle with TMI and SMI. Multiple regression analysis showed that CSA of the GHM was positively associated with both TMI (B = 24.9, p < 0.001) and SMI (B = 13.7, p = 0.002). EIs of swallowing-related muscles were not associated with TMI and SMI. Trunk muscle mass was associated with swallowing-related muscle mass and not muscle quality. The results of this study shed light on the elucidation of association of dysphagia with TMI and SMI.

Associations of swallowing-related muscle quantity and quality with sarcopenic parameters.

PURPOSE: To examine the associations between swallowing-related muscle characteristics and sarcopenic parameters. METHODS: We included 147 community-dwelling older adults (age: 71.6 ± 4.7 years, body mass index: 23.0 ± 2.7 kg/m2 (mean ± standard deviation), men: 50; women: 97) and categorized them into robust (n = 125), low-function (n = 17), and sarcopenia (n = 5) groups based on the diagnostic criteria of the Asia Working Group for Sarcopenia 2019. We evaluated the geniohyoid muscle (GHM) and tongue characteristics (muscle quantity and quality). The cross-sectional area (CSA) indicated the muscle quantity, and echo intensity (EI) values indicated the muscle quality. A multiple regression analysis was performed to clarify the relationship of swallowing-related muscle characteristics and strength with sarcopenic parameters. RESULTS: The grip strength (CSA of GHM: ß = 1.64, p = 0.03) and skeletal muscle mass index (CSA of tongue: ß = 74.81, p = 0.003, EI of tongue: ß = 1.92, p = 0.009) were better indicators of swallowing-related muscle characteristics. CONCLUSION: These findings may facilitate the early detection of aging-related deterioration in swallowing-related musculature through the diagnostic process of sarcopenia and increase our understanding of muscle physiology.

Higher extracellular water/total body water ratio is associated with lower tongue and grip strength: A cross-sectional study.

PURPOSE: This study aimed to investigate the relationship between tongue factors (tongue strength and tongue volume), systemic factors (grip strength and walking speed), and the extracellular water/total body water ratio. METHODS: This cross-sectional study included community-dwelling adults. Body water composition and skeletal muscle mass index were measured using bioelectrical impedance analysis. Moreover, tongue grip strength, tongue volume, occlusal support condition (Eichner classification), and walking speed were measured. Multiple linear regression analysis was performed to investigate the relationship between the tongue and systemic factors as dependent variables and body water composition. RESULTS: We included 171 community-dwelling adults (62 men and 109 women) aged 70.0 years (interquartile range: 8). Tongue strength (r=-0.22, P=0.004) and grip strength (r=-0.39, P<0.001) were correlated with the extracellular water/total body water ratio. In multiple linear regression analysis, tongue strength was associated with the extracellular water/total body water ratio (ß=-0.20, P=0.034), and grip strength was associated with the extracellular water/total body water ratio (ß=-0.12, P=0.047), sex, body mass index, skeletal muscle mass index, and occlusal support condition. CONCLUSIONS: A higher extracellular water/total body water ratio indicates lower tongue and grip strength. Dentists and dental hygienists should be aware of systemic factors present in patients with lower tongue and grip strength. These findings may lead to further medical investigations and diagnosis of other systemic diseases.

The Cross-Sectional Area of the Middle and Base of the Tongue is Associated with Swallowing-Related Muscle Strength.

Muscle strength and function are generally positively correlated with muscle quantity and negatively correlated with muscle quality; however, the tongue shows a unique tendency, different from limb muscles. The relationship between the characteristics of each part of the tongue, muscle strength and function, and systemic factors has been unclear. The aim of the study was to investigate the relationship between cross-sectional area (CSA) and echo intensity (EI) of the middle and base of the tongue and swallowing, articulation function, and body composition. Eighty-nine healthy individuals were included in this cross-sectional study. Swallowing was assessed using tongue pressure (TP) and jaw opening force (JOF) as they indicate swallowing-related muscle strength. Articulation function was evaluated through oral diadochokinesis (ODK). Bioelectrical impedance analysis was performed for body composition. CSAs and EIs of the middle and base of the tongue were measured using ultrasound. Multiple regression analysis was used to examine the relationship between the characteristics of the tongue, swallowing-related muscle strength, and ODK. In multiple regression analysis with TP as the dependent variable, age (ß = - 0.22, P < 0.01) and CSA of the middle part (ß = 0.02, P < 0.01) were significant explanatory variables. In multiple regression analysis with JOF as the dependent variable, sex (ß = - 2.76, P < 0.01) and CSA of the base (ß = - 0.004, P < 0.05) were significant explanatory variables. Multiple regression analysis with articulation function as the dependent variable did not yield significant results. The CSA of the tongue is a better indicator of swallowing-related muscle strength than EI. Ultrasonography may be used for assessing swallowing-related muscle strength.

Age-related changes in swallowing muscle intramuscular adipose tissue deposition and related factors.

OBJECTIVES: To investigate age-related changes in the intramuscular adipose tissue (IAT) of the tongue and geniohyoid muscle (GHM) and associated factors. DESIGN: Exploratory cross-sectional study. SETTING AND PARTICIPANTS: This study included 89 participants recruited from a health survey, which included 38 younger adults (age range, 20-63 years) and 51 older adults (age range, 65-87 years). MEASUREMENTS: Age, body mass index, body fat, lean body mass, skeletal muscle mass index, trunk muscle mass index, tongue pressure, jaw opening force, and oral diadochokinesis were assessed. The cross-sectional area (CSA) and echo intensity (EI) of the tongue and GHM were measured using ultrasonography. IAT was assessed according to EI values. The factors related to the IAT of each muscle were examined using multiple regression analysis. We also investigated the correlation of IAT with factors related to oral function and systemic and morphological factors. RESULTS: Neither the EI of the tongue nor that of the GHM had a significant correlation with factors related to oral function and systemic factors. In the multiple regression analysis, significant explanatory variables for EI of the tongue and GHM were age (ß = 0.14, P = 0.019; tongue and ß = 0.13, P = 0.017; GHM) and the CSA of each muscle (ß = -0.01, P = 0.042; tongue and ß = -0.04, P = 0.003; GHM). EI was positively associated with age and negatively associated with muscle CSA. CONCLUSION: Age-related changes in the IAT show the same trend for both the tongue and GHM, unlike age-related changes in muscle mass. The IATs of the tongue and GHM were not significantly correlated with oral function and systemic factors. Therefore, EI may not be a useful index for the functional evaluation of the tongue and GHM.

Dysphagia in a persistently vegetative patient improved by orthodontic treatment of severe dental misalignment.

INTRODUCTION: We describe the treatment of severe dysphagia in a patient left in a persistent vegetative state after an episode of hypoxic-ischemic encephalopathy following a traffic accident. CASE REPORT: A 38-year-old man was in a persistent vegetative state since a traffic accident in 2005, which resulted in cardiopulmonary arrest and hypoxic-ischemic encephalopathy. His airway had been secured with a tracheostomy, and a gastric tube had been inserted; however, he continued to suffer from urinary tract infections, glossoptosis, and silent aspiration of saliva. Both the maxilla and mandible had very narrow dental arches, with the mandibular incisors exhibiting severe lingual inclination. COURSE: We first corrected the dentition in the narrow maxillary arch, followed by the mandibular arch. As the dental alignment improved, tongue movements appeared during oral care, and endoscopy also revealed signs of an active saliva swallowing reflex. DISCUSSION: The "training approach" generally used to treat severe dysphagia is usually impossible in persistently vegetative patients. In our patient, the tongue movements and saliva swallowing reflex appeared after we expanded the narrow dental arches, suggesting that an orthodontic approach can be effective in such cases. Our findings can be applied to similar cases of vegetative patients to facilitate better oral care and outcomes.

Ultrasonography Shows Age-related Changes and Related Factors in the Tongue and Suprahyoid Muscles.

OBJECTIVES: To investigate age and other factors related to the deterioration of the muscles used for swallowing, including the tongue and suprahyoid muscles. DESIGN: Cross-sectional study. SETTING AND PARTICIPANTS: This study included 146 participants: 47 younger adults (23 men and 24 women; age range 23-44 years) recruited from a dental hospital and 99 community-dwelling older adults (37 men and 62 women, age range 65-86 years). METHODS: Age (<65 years or ≥65 years), body mass index (BMI), skeletal muscle mass index (SMI), and tooth loss (Eichner classification) were measured. The cross-sectional areas (CSAs) of the tongue, geniohyoid muscle, and anterior belly of the digastric muscle were measured using an ultrasonic diagnostic apparatus. The correlation between each muscle's CSA and strength was examined. Multiple regression analyses were performed separately for each sex using each muscle CSA as the dependent variable and age, BMI, SMI, and the Eichner classification as explanatory variables. RESULTS: Older men had a significant positive correlation between tongue pressure and CSA (r = 0.35, P = .031). Jaw opening force was positively correlated with geniohyoid muscle CSA (r = 0.41, P = .001) in older women. In the multiple regression analysis, age, BMI, and SMI were significantly associated with tongue CSA in men. Age was significantly and inversely associated with suprahyoid muscle CSA in both men and women. No explanatory variables were significantly associated with geniohyoid muscle CSA except age. CONCLUSIONS AND IMPLICATIONS: The tongue increased in volume, and the suprahyoid muscles underwent atrophy with age. The study results suggest that interventions to prevent dysphagia associated with aging should be tailored toward specific muscles. Direct muscle training is required for the suprahyoid muscles, whereas the maintenance of tongue muscle mass and function, as well as training for the tongue, requires attention to ensure optimal nutritional status and whole-body skeletal muscle mass.

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.

Relationship between jaw-opening force and neck circumference in healthy older individuals.

AIM: In recent years, the relationships of arm circumference and calf circumference with swallowing function have been reported. However, the efficacy of using the neck circumference, which is closer to the swallowing-related muscles, has never been verified. Jaw-opening force, an indicator of suprahyoid muscle strength, is known to be useful for screening for dysphagia. The aim of the present study was to identify the relationships between neck circumference and swallowing-related muscle strength, and to clarify the association between these variables in older individuals. METHODS: A total of 104 healthy, independent older individuals, aged ≥65 years (36 men, 68 women, mean age 71.5 ± 4.5 years, range 65-83 years), participated in the study. Neck circumference, arm circumference, calf circumference, jaw-opening force and repetitive saliva swallowing test scores were measured. Multiple regression analysis was carried out to determine the relationship between neck circumference and jaw-opening force, between neck circumference and repetitive saliva swallowing test score, and to identify variables affecting jaw-opening force and neck circumference. RESULTS: The participants' mean body mass index was 22.8 ± 2.9 (range 15.8-32.4). Sex and neck circumference, but not arm or calf circumference, were significant independent factors related to jaw-opening force. Independent factors affecting neck circumference were sex, body mass index, jaw-opening force and arm circumference, but not repetitive saliva swallowing test score. CONCLUSIONS: In healthy older individuals, neck circumference was more strongly related to jaw-opening force than were arm or calf circumference. This suggested that neck circumference could be useful for evaluating swallowing-related muscle strength non-invasively and easily. Geriatr Gerontol Int 2019; 19: 330-334.

Association between tongue muscle strength and masticatory muscle strength.

BACKGROUND: The tongue is responsible for compressing food against the palate and squeezing it into the pharynx during the oral preparatory phase of swallowing. Tongue pressure (TP), an indicator of tongue muscle strength, has been observed to decline with age; maximum occlusal force (MOF), an indicator of chewing ability, is correlated with TP. However, no study has investigated the relationship between TP and MOF. OBJECTIVE: To investigate the correlation between TP and MOF according to age in healthy individuals. METHODS: We retrospectively collected handgrip strength (HGS), body mass index (BMI), TP, MOF and tooth loss data for 785 healthy participants (305 men, 480 women). All subjects had either unilateral or bilateral occlusal support, regardless of the presence of dentures or natural teeth. The participants were divided into two groups: an adult (20s-50s, n = 497) group and an elderly (60s-80s, n = 288) group. Multivariate linear regression analysis was performed to determine significant independent variables associated with TP in both groups. RESULTS: Multivariate analysis revealed that TP was significantly associated with age (ß = -0.153), BMI (ß = 0.205), HGS (ß = 0.298) and MOF (ß = 0.239) in the adult group (all P < 0.001) and with age (ß = -0.266, P < 0.001), BMI (ß = 0.160, P = 0.005), MOF (ß = 0.217, P = 0.001) and tooth loss (ß = 0.156, P = 0.011) in the elderly group. CONCLUSIONS: As age and MOF are each associated with TP in both elderly and adult patients, age-related TP decline can be prevented with routine lingual exercises, even before the onset of old age. Additionally, MOF deterioration may indicate a decline in TP for elderly.

Relationship between swallowing muscles and trunk muscle mass in healthy elderly individuals: A cross-sectional study.

BACKGROUND AND OBJECTIVE: A decrease of swallowing muscle strength causes dysphagia, and a relationship between swallowing muscle strength and appendicular muscle mass has been reported. Moreover, the effect of trunk retention function on swallowing function has been clinically recognized. However, the relationship between trunk muscle mass and swallowing muscle strength is unclear. We aimed to clarify the association between these variables in elderly individuals. METHODS: Subjects were 118 healthy community-dwelling individuals aged ≥65 years (men: 37, women: 81). We measured total muscle mass, grip strength, jaw-opening force, tongue pressure, cross-sectional area (CSA) of the geniohyoid muscle, and tongue muscle thickness. The appendicular skeletal muscle mass index (ASMI) and trunk muscle mass index (TMI) were calculated based on the appendicular skeletal muscle mass and trunk muscle mass, and corrected by height squared. Multiple regression analysis was performed with jaw-opening force and tongue pressure as dependent variables and with age, sex, grip strength, ASMI, TMI, CSA of the geniohyoid muscle, and tongue muscle thickness as independent variables. RESULTS: Significant explanatory factors for jaw-opening force were sex (p = 0.002) and TMI (p = 0.003). Significant explanatory factors for tongue pressure were aging (p = 0.001), tongue muscle thickness (p = 0.027), and TMI (p = 0.033). CONCLUSIONS: Until now, the relationship between swallowing muscles and whole body muscle mass has been reported using ASMI as the indicator of whole body muscle mass. This study suggests that TMI may be used as a highly relevant indicator of swallowing muscles rather than ASMI.