Comparison of Tongue Characteristics Classified According to Ultrasonographic Features Using a K-Means Clustering Algorithm.

The precise correlations among tongue function and characteristics remain unknown, and no previous studies have attempted machine learning-based classification of tongue ultrasonography findings. This cross-sectional observational study aimed to investigate relationships among tongue characteristics and function by classifying ultrasound images of the tongue using a K-means clustering algorithm. During 2017-2018, 236 healthy older participants (mean age 70.8 ± 5.4 years) were enrolled. The optimal number of clusters determined by the elbow method was 3. After analysis of tongue thickness and echo intensity plots, tongues were classified into three groups. One-way ANOVA was used to compare tongue function, tongue pressure, and oral diadochokinesis for /ta/ and /ka/ in each group. There were significant differences in all tongue functions among the three groups. The worst function was observed in patients with the lowest values for tongue thickness and echo intensity (tongue pressure [P = 0.023], /ta/ [P = 0.007], and /ka/ [P = 0.038]). Our results indicate that ultrasonographic classification of tongue characteristics using K-means clustering may aid clinicians in selecting the appropriate treatment strategy. Indeed, ultrasonography is advantageous in that it provides real-time imaging that is non-invasive, which can improve patient follow-up both in the clinic and at home.

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.

Tongue thickness is associated with masticatory performance of perioral muscles: Ultrasonographic study of perioral muscle characteristics in healthy young subjects.

BACKGROUND: Mastication is a complicated task that involves the teeth and perioral muscles, such as the tongue and lip. Previous studies have shown correlations between masticatory performance and perioral muscle strength (eg tongue pressure) and between masticatory performance and occlusal forces. OBJECTIVE: To investigate the relationships between masticatory performance and perioral muscle characteristics. METHODS: Forty-nine healthy young subjects (men: 24 and women: 25) with Eichner classification group A were included in this cross-sectional study. Age, body weight, masticatory performance, masseter muscle thickness, masseter muscle echo intensity, cross-sectional area of geniohyoid muscle, geniohyoid muscle echo intensity, tongue thickness (TT) and tongue echo intensity were assessed. Masticatory performance was evaluated using a colour-changeable chewing gum. The thickness and echo intensity of the masseter muscle, geniohyoid muscle and tongue were observed using an ultrasonic diagnostic apparatus. Stepwise multiple regression analysis was conducted to examine relationships between perioral muscle characteristics and masticatory performance. RESULTS: Tongue thickness (P < .01) was the sole significant explanatory variable for masticatory performance. The standard partial regression coefficient was 0.47. The multiple correlation coefficient (R) was .47, and the adjusted R2 was .20; the variance inflation factor was 1.0. This study showed that TT was related to masticatory performance, whereas perioral muscle quality was not. Moreover, perioral muscle quantity was highly correlated with perioral muscle quality. CONCLUSIONS: Tongue thickness is a predictor of masticatory performance in healthy young subjects. An ultrasonic diagnostic apparatus is useful in the evaluation of perioral muscle characteristics.

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.

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.

Association between echo intensity of the tongue and its thickness and function in elderly subjects.

BACKGROUND: The tongue plays an important role during the oropharyngeal phase of swallowing. Each part of the tongue has a different function during swallowing. Ageing causes changes in muscle quantity and quality. Qualitative changes, such as an increase in intramuscular adipose tissue, can be determined by the echo intensity (EI) of the tongue on ultrasonography (US). OBJECTIVE: To clarify the relationship between EI and thickness and function of the tongue. METHODS: Ninety-four healthy elderly individuals (30 male, 64 female) aged >65 years (mean 71.10 ± 4.13 years) were enrolled. Tongue thickness (TT) and EI were determined by US. Tongue function was evaluated by measurement of tongue pressure and oral diadochokinesis (OD). Multiple regression analysis was used to identify the factor with the strongest influence on EI of the tongue. RESULTS: The mean thickness of the middle of the tongue was 40.42 ± 4.24 mm and that of the base was 23.35 ± 3.32 mm; the respective EI values were 46.54 ± 9.33 and 49.33 ± 9.83. The average OD rates for /ta/ and /ka/ were 5.73 ± 1.09 and 5.40 ± 1.00 times/s, respectively. Multiple regression analysis for EI showed that /ta/ (ß = -2.518, P = 0.042) and thickness of the middle of the tongue (ß = -1.278, P < 0.001) were significant independent variables. Similarly, the EI at the base of the tongue showed that /ka/ (ß = -4.038, P = 0.021) and base of TT (ß = -0.913, P = 0.004) were significant independent variables. CONCLUSION: EI may be an indicator of TT and OD in both the middle and base of the tongue. Ultrasound is beneficial for evaluating TT and function.