A Novel Three-Dimensional Analysis of Tongue Movement During Water and Saliva Deglutition: A Preliminary Study on Swallowing Patterns

Determination of Micromovements in Removable Prosthesis during Mastication: A Pilot Study with 3D Electromagnetic Articulography

Edentulism can generate negative impacts on self-esteem, interpersonal relationships, and oral functions. Removable prostheses are commonly used for tooth replacement, but they may cause discomfort due to micromovements during mastication. Objective and quantifiable methods are needed to evaluate these micromovements. A pilot study was conducted to determine the micromovements in removable prostheses during mastication using a 3D electromagnetic articulography (EMA-3D) system. One elderly participant wearing lower removable prostheses and an upper total well-fitting removable prosthesis was studied. The EMA-3D system was used to record movements in three spatial planes. Peanuts were given as test food, and the participant was instructed to chew normally while recordings were carried out until feeling the need to swallow. Analyses of the upper total prosthesis show micromovements ranging from 0.63 ± 0.11 to 1.02 ± 0.13 mm. During simultaneous analyses of the upper prosthesis and lower partial prosthesis, interference was not observed. This pilot study demonstrated the feasibility of using the EMA-3D system to evaluate micromovements in removable prostheses during mastication. Further research is needed to evaluate a larger sample and assess the clinical implications of these micromovements.

A Novel Technique to Accurately Measure Mouth Opening Using 3D Electromagnetic Articulography

The mouth opening is an important indication of the functionality of the temporomandibular joint (TMJ). Mouth opening is usually evaluated by asking the patient to open their mouth as wide as possible and measuring the distance between the edges of the frontal incisors with a ruler or caliper. With the advancement of technology, new techniques have been proposed to record mandibular movement. The aim of this work is to present a novel technique based on 3D electromagnetic articulography and data postprocessing to analyze the mouth opening considering distances, trajectories, and angles. A maxilla-mandible phantom was used to simulate the mouth opening movement and fixed position mouth opening. This was recorded using the AG501 3D EMA (Carstens Medizinelektronik GmbH, Bovenden, Germany). The collected data was processed using Matlab (Mathworks, Natick, MA, USA). Fix and mobile mouth opening of 1, 2, 3 and 4 cm were simulated. It was possible to evaluate the mandibular opening through the vertical distance, the Euclidean distance, the trajectory, and the opening angle. All these values were calculated and the results were consistent with expectations. The trajectory was the highest value obtained while the vertical distance was the lowest. The angle increased as the mouth opening increased. This new technique opens up new possibilities in future research since oral opening can be analyzed using multiple variables without the need to use different devices or depending on the researcher’s experience. This will make it possible to establish which parameter presents significant differences between groups of patients or between patients who have undergone some treatment.

Noninvasive Evaluation of the Biomechanical Accommodations to Bolus Volume during Human Swallowing

Bolus volume is very important in the biomechanics of swallowing. By noninvasively characterizing swallow responses to volume challenges, we can gain more knowledge on swallowing and evaluate swallowing behavior easily. This study aimed to evaluate the impact of bolus volume on the biomechanical characteristics of oropharyngeal swallowing events with a noninvasive sensing system. Fifteen healthy male subjects were recruited and instructed to swallow 5, 10, and 15 ml of water. The sensing system consisted of a tongue pressure sensor sheet, bend sensor, surface electrodes, and a microphone. They were used to monitor tongue pressure, hyoid activity, surface EMG of swallowing-related muscles, and swallowing sound, respectively. In addition to the onset, the peak time and offset of the above four structures, certain characteristics, such as the duration, peak value, and interval of the structure motions, were measured during the different drinking tasks. The coordination between the hyoid movement and tongue pressure was also assessed. Although no sequence of the structural events changed with volume, most of the timings of the structural events were significantly delayed, except for certain hyoid activities. The swallowing volume did not affect the active durations of the monitored structures, the peak values, or intervals of tongue pressure and supra- and infrahyoid muscle activity, but certain hyoid kinetic phases were prolonged when a larger volume was swallowed. Additionally, sequential coordination between hyoid movement and tongue pressure was confirmed among the three volumes. These findings suggest that oropharyngeal structural movements change in response to bolus volume to facilitate safe swallowing. The noninvasive and quantitative measurements taken with the sensing system provide essential information for understanding normal oropharyngeal swallowing.

Modulation of tongue motion and tongue pressure during liquid swallowing with different bolus volumes

BACKGROUND

The tongue functions by modulating according to bolus volume when swallowing; however, associated tongue dynamics are unclear.

OBJECTIVE

We aimed to clarify how tongue motion and tongue pressure change with bolus volume during swallowing.

METHODS

Sixteen healthy volunteers (age 29.5 ± 3.8 years; 12 males, 4 females) were recruited. Two electromagnetic articulography markers were attached, one each on the anterior and posterior parts of the tongue, to measure motion. A sensor sheet, with five pressure-sensitive points, was attached to the hard palate to measure tongue pressure. Participants were asked to swallow 3 ml and 10 ml of water. Motion trajectory, maximum velocity, vertical displacement just before contact with the hard palate, and maximum magnitude and duration of tongue pressure were analysed.

RESULTS

Tongue rotation was observed in the sagittal plane; its rate of appearance was significantly higher when swallowing 3 ml of water than when swallowing 10 ml, and the rate of rotation at posterior part was significantly higher than at the anterior part. The maximum velocity and vertical displacement were significantly greater when swallowing 10 ml of water than those when swallowing 3 ml of water. There was no significant difference in either the maximum magnitude of tongue pressure or maximum duration of tongue pressure between 3 ml and 10 ml.

CONCLUSION

Bolus volume influenced the pattern of tongue motion; however, there was no difference in tongue pressure.

Using Voice Change as an Indicator of Dysphagia: A Systematic Review

Voice change post-swallow, observed during a clinical swallow examination, is often used as a clinical indicator of dysphagia risk. However, there has been limited research that evaluated the level of agreement between voice change and swallow dysfunction reported to date. This systematic review aims to investigate existing evidence relating to the relationship between vocal change post-swallow and swallow deficits identified on a Videofluoroscopic Swallow Study (VFSS). The studies were selected by two independent evaluators for inclusion, without restriction on language or date of publication and the methodological quality and the risk of bias were assessed using QUADAS-2. Following the PRISMA recommendation, 271 articles were analyzed, of which 17 were included in the study. Of these, the methodology described in five studies employed voice analyses using only acoustic methods, seven others conducted only auditory-perceptual analyses, and five other studies used both. Across the studies there was no homogeneity in the voice quality parameters assessed, analytic methods used, and results obtained. Forty seven per cent of the studies presented a high risk of bias in the analysis of vocal quality due to lack of clarity and blinding of VFSS. There was no homogeneity in the choice of consistencies evaluated during swallowing, as well as standardization of the outcome investigated in VFSS without a vocal parameter attributable to accurate detection in each outcome. It is not possible to obtain a consensus regarding the recommendation of the use of vocal evaluation as an accurate method for identifying swallowing alterations due to heterogeneity of the vocal evaluation methods, the outcomes evaluated in the VFSS examination, heterogeneity in food and liquid consistencies, and the methodological quality of the studies.

Coordination of surface electromyography activity in the posterior tongue region during mastication of differently textured foods

BACKGROUND

Masticatory movement occurs complicatedly and bilaterally. Although the tongue plays an important role in mastication, bilateral tongue function during mastication has not been clarified yet.

OBJECTIVE

To investigate the effect of food properties on posterior tongue activity and coordination of muscles bilaterally by electromyography (EMG).

METHODS

Twenty healthy adults (10 males and 10 females; mean age 28 years; range: 22-33 years) participated in this study. Three test foods, gummy jelly (hard food), sponge cake (soft food requiring crushing), and mashed potatoes (soft food not requiring crushing), were used. Bilateral masseter N-EMG (surface electromyography for measuring the muscle activity of posterior tongue) and submental EMG were carried out while the participants chewed three test foods. The participants were instructed to masticate three test foods only on the right side and only on the left side unilaterally.

RESULTS

In the case of gummy jelly, N-EMG activity on the mastication side was significantly larger than that on the non-mastication side (P < .01). Regarding temporal relationship between the masseter and N-EMG activity, in the case of gummy jelly, the percentage of cases where the N-EMG peak was observed during masseter muscle EMG bursts was significantly higher than those for sponge cake and mashed potatoes (P < .01).

CONCLUSION

N-EMG activity on the mastication side was significantly larger than that on the non-mastication side in the mastication of hard foods. Tongue showed activity pattern changes and coordinated with the masseter muscle depending on food texture.

Description of tongue movements on swallowing patterns

OBJECTIVE

The purpose of this study was to compare the different swallowing patterns regarding tongue movement during saliva swallowing in healthy participants.

DESIGN

Seventeen participants (23.0 ± 3.6 years old) were included in this cross-sectional study. The movement of the tongue (anterior, middle and posterior portions) on the three axes of space (inferior-superior, anterior-posterior and medial-lateral) was recorded using a 3D electromagnetic articulograph. The tongue movement patterns registered during saliva swallowing were classified according to Bourdiol et al. (2014) into Type I, II or III.

RESULTS

Three swallowing patterns were identified (Type I, 64.7 %; Type II, 5.9 %; and Type III, 29.4 %). On the anterior-posterior axis, the displacement of the three portions of the tongue was significantly higher in Type III pattern compared with the Type I pattern. Furthermore, on the superior-inferior axis, the displacement of the anterior portion was significantly higher in Type III pattern compared with Type I pattern. In Type I pattern, on the inferior-superior axis, the smallest range of displacement occurred in the anterior portion of the tongue, followed by the middle and, finally, the posterior portion. In the analysis of Type III swallowing pattern, no significant differences were found on the range of displacement of the tongue portions on the three axes.

CONCLUSION

Statistical differences were found between swallowing patterns Type I and III regarding tongue movement. The frequency of pattern II found in the participants of this study was not high enough to compare the three patterns. However, the results obtained indicate that the methodology applied could be used to identify the patterns based on quantitative data.