Search Results (74)

Background: Spinal muscular atrophy (SMA) is a neuromuscular disorder that frequently affects bulbar function, including feeding and swallowing. Although disease-modifying therapies have improved motor outcomes, little is known about the persistence of oromotor difficulties, particularly with regard to solid food intake. Objective: This study aimed to evaluate mastication and swallowing performance in children with SMA undergoing treatment, and to investigate the association between tongue strength and feeding efficiency. Methods: Twenty-two children with SMA types 1–3 were assessed using the Test of Masticating and Swallowing Solids in Children (TOMASS-C) and the Iowa Oral Performance Instrument (IOPI). Key TOMASS-C outcomes included the number of bites, chewing cycles, swallows, and total eating time. Tongue strength was measured in kilopascals. Results: Most participants showed deviations from age-specific normative values in at least one TOMASS-C parameter. Tongue strength was significantly lower than reference values in 86% of participants and correlated negatively with all TOMASS-C outcomes (p < 0.001). Children with weaker tongue pressure required more swallows, more chewing cycles, and longer eating times. Conclusions: Despite pharmacological treatment, children with SMA experience persistent difficulties in eating solid foods. Tongue strength may serve as a non-invasive biomarker for bulbar dysfunction and support dietary decision-making and therapeutic planning. Full article

Background/Objectives: Temporomandibular disorders (TMDs) are a group of musculoskeletal and neuromuscular conditions involving the temporomandibular joint (TMJ), masticatory muscles, and related anatomical structures. Although magnetic resonance imaging (MRI) is considered a noninvasive and highly informative imaging modality for assessing TMJ soft tissues, few studies have examined how TMJ structural features observed on MRI findings relate to oral function and craniofacial morphology in female patients with malocclusion. To investigate the associations among TMJ structural features, oral function, and craniofacial morphology in female patients with malocclusion, using MRI findings interpreted in conjunction with a preliminary assessment based on selected components of the DC/TMDs Axis I protocol. Methods: A total of 120 female patients (mean age: 27.3 ± 10.9 years) underwent clinical examination based on DC/TMDs Axis I and MRI-based structural characterization of the TMJ. Based on the structural features identified by MRI, patients were classified into four groups for comparison: osteoarthritis (OA), bilateral disk displacement (BDD), unilateral disk displacement (UDD), and a group with Osseous Change/Disk Displacement negative (OC/DD (−)). Occlusal contact area, occlusal force, masticatory efficiency, tongue pressure, and lip pressure were measured. Lateral cephalometric analysis assessed skeletal and dental patterns. Results: OA group exhibited significantly reduced occlusal contact area (p < 0.0083, η² = 0.12) and occlusal force (p < 0.0083, η² = 0.14) compared to the OC/DD (−) group. Cephalometric analysis revealed that both OA and BDD groups had significantly larger ANB angles (OA: 5.7°, BDD: 5.2°, OC/DD (−): 3.7°; p < 0.0083, η² = 0.21) and FMA angles (OA: 32.4°, BDD: 31.8°, OC/DD (−): 29.0°; p < 0.0083, η² = 0.17) compared to the OC/DD (−) group. No significant differences were observed in masticatory efficiency, tongue pressure, or lip pressure. Conclusions: TMJ structural abnormalities detected via MRI, especially osteoarthritis, are associated with diminished oral function and skeletal Class II and high-angle features in female patients with malocclusion. Although orthodontic treatment is not intended to manage TMDs, MRI-based structural characterization—when clinically appropriate—may aid in treatment planning by identifying underlying joint conditions. Full article

This paper introduces a wearable silent text input system designed to capture text input through silent speech, without generating audible sound. The system integrates Electromyography (EMG) and piezoelectric lead zirconate titanate (PZT) sensors in a miniaturized form that can be comfortably attached to the chin, making it both comfortable to wear and esthetically pleasing. The EMG sensor records muscle activity linked to specific tongue and jaw movements, while the PZT sensor measures the minute vibrations and pressure changes in the chin skin caused by silent speech. Data from both sensors are analyzed to capture the timing and intensity of the silent speech signals, allowing the extraction of key features in both time and frequency domain. Several machine learning (ML) models, including both feature-based and non-feature-based approaches commonly used for classification tasks, are employed and compared to detect and classify subtle variations in sensor signals associated with individual alphabet letters. To evaluate and compare the ML models, EMG and PZT signals for the eight most frequently used English letters are collected across one hundred trials each. Results showed that non-feature-based models, particularly the Fea-Shot Learning with fused EMG and PZT signals, achieved the highest accuracy (95.63%) and F1-score (95.62%). The proposed system’s accuracy and real-time performance make it promising for silent text input and assistive communication applications. Full article

Background and Objectives: Sufficient evidence supports the Iowa Oral Performance Instrument (IOPI) as a reliable tool for measuring tongue strength and endurance as well as an effective assessment instrument for intervention studies. This study aimed to investigate the impact of a tongue training device, the HEAL, on tongue muscle strength in patients with obstructive sleep apnea (OSA) following modified uvulopalatopharyngoplasty (UPPP), utilizing the IOPI for evaluation. Materials and Methods: We introduced a tongue strengthener, the HEAL, made from medical-grade silicone, designed to improve tongue strength. Each patient was provided with the HEAL and instructed to begin using it one month after undergoing modified UPPP for OSA. The tongue strength of OSA patients was measured using the IOPI both before using the HEAL and approximately 6 weeks later. Results: A total of 66 participants with OSA underwent modified UPPP and were included in the final analysis. The mean age was 39.15 ± 8.84 years, and the mean BMI was 27.41 ± 4.03 kg/m². The duration between the pre- and post-assessment of tongue strength using the HEAL was 42.95 ± 17.97 days. The mean tongue strength pressure before and after using the HEAL was 32.16 ± 16.00 kilopascals (kPa) and 42.95 ± 17.97 kPa, respectively. Tongue strength increased by an average of approximately 52.8% after using the HEAL for an approximate duration of 6 weeks. Conclusions: In the current study, participants with OSA who had undergone modified UPPP and subsequently used the HEAL demonstrated an average improvement of 10.79 kPa in tongue strength—an increase of over 50%—as measured by the IOPI. The interval between the pre- and post-assessment of tongue strength was approximately six weeks. Further studies are needed to validate these findings. Full article

Cavitation is a complex multiphase flow phenomenon, and the generation of transient phase transitions between liquid and vapor during cavitation development leads to multi-scale vortex motion. The transient cavitation dynamics and centrifugal pump’s rotor–stator interaction will induce pressure fluctuations in the impeller and the volute fluid of the centrifugal pump, resulting in a complex flow field structure. Based on the Schnerr–Sauer cavitation model and SST k-ω turbulence model, this paper studies the transient characteristics of the cavitation-induced unsteady flow in the centrifugal pump and the excitation response to the pressure pulsation in the volute under different flow conditions, taking the large vertical double-volute centrifugal pump as the research object. The results indicate the following: As the impeller rotates, in the external excitation response, the jet-wake flow structure at the centrifugal pump blade outlet shows an increase in the blade frequency signal. This is evident near the measurement points of the volute tongue and separator. When severe cavitation occurs, the maximum amplitude at the blade frequency in the volute shifts from the pump tongue (30°) to the downstream of the tongue (45°). The value of f_pmax is 3.1 times that when NPSHa = 8.88 m. By applying the Omega vortex identification method, it can be seen that the interaction between the vortices at the blade trailing edge and the stable vortex in the volute tongue undergoes a process of elongation, fusion, separation, and recovery. This represents the downstream influence of the impeller on the volute. When Q = 0.9Q_d, the process of the blade passage vortex tail detaching and dissipating in the impeller flow path can be observed, demonstrating the upstream influence of the volute on the impeller. Full article

Background: Swallowing dysfunction is a prevalent but often overlooked problem in long-term care facilities. This study investigated the relationships between nutritional deficits, frailty, oral health, and swallowing dysfunction. Additionally, we explored the associations between oral muscle weakness, frailty markers, and swallowing dysfunction. Methods: We recruited 373 participants from seven long-term care facilities across Taiwan. Swallowing function, frailty, nutrition status, and oral health were assessed by research staff. Oral muscle function was evaluated through tongue strength measurements, cheek bulging function tests, the Repetitive Saliva Swallowing Test (RSST), and a diadochokinetic task. Frailty was assessed through grip strength as well as mid-upper arm and calf circumference measurements. Results: The Functional Oral Intake Scale revealed that 97 participants (26%) had swallowing dysfunction. Participants with swallowing dysfunction had poorer nutritional status, higher frailty levels, and worsened oral health. Frailty was the factor most strongly associated with swallowing dysfunction. Participants with swallowing dysfunction also exhibited lower tongue pressure, decreased cheek-bulging ability, fewer repetitions in the diadochokinetic task, lower scores on the RSST, lower calf circumferences, and lower grip strength. Logistic regression demonstrated that cheek bulging was most strongly associated with swallowing dysfunction. Furthermore, lower grip strength was significantly associated with swallowing dysfunction. Conclusions: Frailty was most strongly associated with swallowing dysfunction, followed by poorer nutritional status and worsened oral health. These factors should be thoroughly assessed in long-term care residents. Participants with swallowing dysfunction also experienced oral muscle weakness, particularly in cheek bulging. Grip strength, which represents frailty, was directly associated with swallowing dysfunction and could serve as a crucial indicator of swallowing dysfunction. Full article

Background: We examined the factors associated with low tongue pressure to clarify its association with physical abnormalities in adolescent and young adult women. Methods: This study enrolled 92 women aged 10–20 years. Following the collection of anthropometric data, measurements were performed, including grip strength, maximum occlusal force, maximum tongue pressure, and masticatory performance. Based on the Rohrer index and body mass index (BMI), the participants were divided into normal weight, underweight, and overweight/obese groups. Low tongue pressure was defined as the bottom 20th percentile of maximum tongue pressure. After univariate analyses, factors associated with low tongue pressure were identified using multivariate binomial logistic regression analysis. Results: In the bivariate analysis, maximum tongue pressure was significantly positively correlated with grip strength (r = 0.407, p < 0.05). Binomial logistic regression analysis revealed that factors associated with low tongue pressure included being underweight (odds ratio [OR] = 7.451, p = 0.005, 95% confidence interval [CI] = 1.857–29.898), being overweight/obese (OR = 18.384, p = 0.004, 95% CI = 2.483–136.112), and having lower grip strength (OR = 0.864, p = 0.015, 95% CI = 0.768–0.972). Conclusions: Low tongue pressure is closely associated with being underweight, being overweight, and having lower grip strength among young women. Full article

Background/Objectives: Health management in workers in the taxi industry is particularly challenging due to irregular working hours and the need to prevent fatal accidents. In addition, drivers in Japan are aging, and the early prevention of age-related deterioration in oral health is an increasingly important issue. The aim of this cross-sectional study was to investigate the relationships between oral diadochokinesis (OD), tongue pressure, and lip-seal strength in Japanese male taxi workers. Methods: Measurements of tongue pressure and lip-seal strength were performed by dentists using specialized equipment. OD was measured using the number of consecutive “Pa”, “Ta”, and “Ka” vocalizations that could be produced in 5 s. We performed multiple regression analysis to examine the effects of lip-seal strength and tongue pressure on OD. Results: The study included 437 participants, excluding 17 who could not complete all oral cavity measurements. Tongue pressure showed a significant positive correlation with “Pa”, “Ta”, and “Ka” (correlation coefficients: 0.527–0.680). Lip-seal strength was not significantly correlated with OD. Tongue pressure showed a significant positive correlation with “Pa”, “Ta”, and “Ka”. In the results of multiple regression analyses without the elderly participants, tongue pressure was associated with “Pa” (β[95% confidence interval]: 0.574[0.304, 0.843]), “Ta” (0.436[0.231, 0.640]), and “Ka” (0.424[0.210, 0.639]), and lip-seal strength was associated with “Pa” (0.128[0.032, 0.224]) and “Ka” (0.083[0.006, 0.160]). Conclusions: OD may be associated with lip-seal strength and tongue pressure even without including elderly workers. Regardless of age, maintaining good OD may help maintain lip-seal strength and tongue pressure, which may play a role in reducing the risk of age-related oral disorders. Full article

Background: The chin-tuck maneuver has been suggested to increase suprahyoid muscle activation, but a method to measure the strength of the chin-tuck maneuver has not been established. We developed a method to measure the strength of the chin-tuck maneuver (chin-tuck strength) and examined the reliability and validity of chin-tuck-strength measurement in community-dwelling older adults. Participants and Methods: The participants were 233 older adults aged ≥65 years without dysphagia or physical disability. Chin-tuck strength was measured twice consecutively using the developed device, and reproducibility was analyzed using intraclass correlation coefficients (ICCs). In addition, maximum tongue pressure, oral diadochokinesis, grip strength, knee extension strength, and the timed up and go test (TUGT) were measured as indices of swallowing-related muscle function and appendicular muscle function. The associations of chin-tuck strength with swallowing-related muscle function and appendicular muscle function were analyzed statistically. Results: The ICCs for chin-tuck strength were 0.82 (95% confidence interval [CI]: 0.73–0.88) in males and 0.87 (95% CI: 0.70–0.93) in females. Chin-tuck strength was significantly associated with maximum tongue pressure, grip strength, knee extension strength, and TUGT. Conclusions: This study suggests that chin-tuck strength is a reliable and valid assessment of swallowing-related muscle strength. Full article

Background: The present study analyzed the relationship between oral motor and cognitive functions in community-dwelling older Korean adults. Methods: Study participants included 113 community-dwelling older adults with a mean age of 73.84 years. Subjects’ cognition was assessed using the Korean version of the Montreal Cognitive Assessment, and tongue, cheek, and lip pressures were assessed using the Iowa Oral Performance Instrument. Tongue and masseter thicknesses were measured using an ultrasound device (Sonon, Healcerion, Roseville, CA, USA). The occlusal force was measured using a specialized device (Innobyte, Kube Innovation, Montreal, QC, Canada), and the number of lost teeth was directly verified by a dental hygienist. Results: Results of analysis of cognitive function according to demographic characteristics of older community-dwelling adults revealed a significant difference in cognitive function according to education level and employment status. Cognitive function demonstrated a positive correlation with oral motor function, including pressure on the cheek, lips, and tongue, thickness of the masseter and tongue, occlusal force, number of lost teeth, and age. Hierarchical regression analysis revealed that demographic characteristics and cheek, lip, tongue, and masseter functions did not affect cognition, whereas occlusal force and number of lost teeth significantly affected cognition. In this study, oral motor function, excluding occlusal force and number of lost teeth, did not affect cognition. Conclusions: Future studies, however, are required to analyze the relationship between oral motor function and cognition in older adults with a wider range of such functions. Full article

Purpose: This study examined lifespan changes in maximum tongue strength, swallowing time, and masseter activity during swallowing. It provides normative data with which to compare clinical assessments of orofacial myofunctional disorders (OMD) and oropharyngeal dysphagia (OPD). Method: 409 healthy participants without identified OMD or OPD (ages 5–79 years) provided instrumental measures of tongue strength and electromyographic measurements for oropharyngeal transit time and masseter activity during swallows of four boluses. Participants were placed in three broad age groups (5–15, 16–59, 60–79) for cross-sectional analysis. Results: Differences were found between age groups for tongue strength, such that the youngest group had significantly lower anterior tongue strength than the other groups, and lower posterior tongue strength than the 16–59 age group. Anterior tongue strength was significantly greater for males than females; posterior tongue strength did not differ significantly between the sexes. The youngest group had longer oropharyngeal transit times than either of the two older groups for most boluses. Swallowing transit time decreased in duration across the age groups, from youngest to oldest, for the 2.5 cc pudding bolus. Both right and left masseters differed in activation among tasks and age groups. The oldest age group had consistently greater levels of activation of the right masseter, and all groups had greater activation for the cracker bolus. Spearman rank-order correlations largely confirmed the inferential statistics and provided evidence of a relationship between tongue weakness and increased oropharyngeal transit time. Conclusion: Maximum tongue pressure generation and oropharyngeal timing measures support a developmental hypothesis, with lower tongue strength and longer swallowing transit times for children ages 5 through 15. The smaller pudding bolus provided the greatest differentiation among the age groups, which may prove to be a functional indicator for clinical evaluation. These results are largely consistent with existing data for tongue strength and oropharyngeal swallowing transit times. Full article

In our previous article, we observed and measured a spontaneous growth in the coronal direction of the keratinized tissues present around implants. This growth involved both free margins and interdental papillae, and we indicated our hypothesis on the probable cause of this still-unexplained phenomenon. The growth of oral soft tissues involves several other structures, such as the linea alba and tongue indentation. Our idea holds that growth of these tissues is generated by the negative intraoral pressure created in the oral phase of swallowing and the subsequent resting position, which through the resulting suction causes a shift of these soft structures in the gaps around the dental crowns. Other hypotheses have been suggested in the past to understand this phenomenon of soft tissue growth, which still lacks data supporting etiological evidence. The purpose of this article is to thoroughly analyze and verify our model by comparing the clinical observations with citations and examples from the literature, combined with notions of physiology, biology, and physics that help in clarifying these events. To better explain the mechanisms of oral soft tissue growth, photographs of clinical cases paradigmatic of the phenomenon are shown. Full article

Purpose: The deterioration of oral function has received much attention, also being referred to as “Oral frailty”. This study evaluated the change in tongue pressure, one of the objective items of oral frailty, to examine the relationship between body position and tongue pressure. Methods: This study was a prospective, observational study conducted in a single center. The participants were categorized by their Clinical Frailty Scale (CFS) scores. Tongue pressure was measured in the following positions: dorsal, sitting, and sitting with plantar grounding. Differences in tongue pressure between CFS and between body positions were statistically analyzed. Results: A significant decrease in tongue pressure was demonstrated in CFS4 compared to CFS3. Furthermore, in CFS5 and CFS6, tongue pressure decreased in the sitting position compared to that in the dorsal position, and tongue pressure recovered to the dorsal level with plantar grounding. Conclusions: Tongue pressure decreased with the progression of frailty. It was decreased by sitting, and this decrease was alleviated by plantar grounding. Full article

Background and Objectives: Muscle strength evaluation using high-density surface electromyography (HD-sEMG) was recently developed for the detailed analysis of the motor unit (MU). Detection of the spatial distribution of sEMG can detect changes in MU recruitment patterns resulting from muscle-strengthening exercises. We conducted a prospective study in 2022 to evaluate the safety and feasibility of transcutaneous electrical sensory stimulation (TESS) therapy using an interferential current device (IFCD) in patients with head and neck squamous cell carcinoma (HNSCC) undergoing chemoradiotherapy (CRT), and reported the safety and feasibility of TESS. We evaluated the efficacy of swallowing exercises in patients with HNSCC undergoing CRT and determined the significance of sEMG in evaluating swallowing function. Materials and Methods: In this supplementary study, the patients performed muscle-strengthening exercises five days a week. The association of the effects of the exercises with body mass index, skeletal muscle mass index, HD-sEMG, tongue muscle strength, and tongue pressure were evaluated. Results: We found significant correlations between the rate of weight loss and skeletal muscle mass index reduction and the rate of change in the recruitment of the MU of the suprahyoid muscle group measured using HD-sEMG. Conclusions: We believe that nutritional supplementation is necessary in addition to muscle strengthening during CRT. Full article

No specific methods have been officially proposed for the prevention and improvement of oral hypofunction. Therefore, in this randomized controlled trial, we aimed to develop a gum-chewing training program and determine its effects in older adults. A total of 218 older adults, aged 65–85 years, were randomly allocated to the intervention or control groups. The intervention group chewed the experimental gum daily, whereas the control group consumed the experimental granular food daily. The outcome assessments measured the maximum bite force, occlusal contact areas, oral dryness, tongue pressure, tongue and lip functions, masticatory function, and gum-chewing time. The measured values for each outcome were compared between groups using the Mann–Whitney U test and within groups pre- and post-intervention using the Wilcoxon signed-rank test. A total of 211 participants completed the study. After 2 months, the intervention group had a significantly higher maximum bite force than the control group (p = 0.01), indicating that gum-chewing training improved maximum bite force in older adults. This was determined using one type of bite force measuring device. Therefore, it is suggested that gum-chewing training has a high potential to improve oral hypofunction. Full article