TONGUE-PALATE INTERACTIONS DURING SWALLOWING

In situ quantitative assessment of food oral processing parameters: A review of feasible techniques and devices

Oral processing is a combination of various actions, the detailed description of which has always been the subject of relevant research. By means of imaging technology and sensory evaluation, more knowledge of oral processing have been accumulated. Presently, the advances in sensory technology have added quantitative parameters to the qualitative description of oral processing, which also enriched the specifics of each action. Previous studies have shown that oral processing includes lip closure, dental occlusion, masticatory muscles activity, tongue movement, and swallowing, whose processing contains rich information such as the movement of organ and the intensity of organ contacts. "Quantification" was taken in this review as the basic feature of in situ detection information, the relevant parameters and feasible methods for the quantitative description of each activity was recorded in detail. In addition, basic problems and feasible optimization schemes of the existing in situ detection device are also proposed in the hope of promoting the development of in situ detection device thus providing available information for the description of oral processing.

Factors Influencing Oral Bolus Hold Type: Tipper or Dipper

Purpose

This retrospective study investigated the impact of age, sex, and swallow task on bolus hold location during cued liquid swallows in healthy, community-dwelling adults. Furthermore, we investigated the association between bolus hold location and Modified Barium Swallow Impairment Profile (MBSImP) Components 2 (bolus hold) and 4 (lingual transport) scores.

Method

Cued swallows of standardized barium liquids (thin, nectar-thickened, honey-thickened) observed during videofluoroscopy in 195 participants were judged as either tipper or dipper bolus hold type. Logistic regression was used to determine relationships between bolus hold location and age, sex, and swallow task. Fisher's exact test was used to determine associations between MBSImP scores and bolus hold type.

Results

The majority of swallow tasks (95%) were of tipper bolus hold type. A significant relationship was observed between age and bolus hold type for swallows of 5-ml thin liquid and 5-ml honey-thickened liquid, with older individuals more likely to demonstrate a tipper bolus hold type. Sex was observed to be a significant factor for two swallow tasks (cup sip of thin liquid and 5 ml of nectar-thickened liquid), with males being more likely to be dippers. No significant relationships were observed between bolus hold type and MBSImP Component 2 or 4 scores.

Conclusions

A tipper bolus hold type was the most common type observed in healthy adults, although the dipper bolus hold type was also observed (albeit at a lower frequency). These study findings further contribute to defining typical swallowing behaviors.

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.

Exploring variability in detection thresholds of microparticles through participant characteristics

This study investigated how product familiarity and physiological characteristics of participants affect detectability of microparticles in viscous and semi-solid foods.

Challenges in computational modelling of food breakdown and flavour release

A dynamic, three dimensional (3D) computational model that predicts the breakdown of food and the release of tastants and aromas could enhance the understanding of how food is perceived during consumption. This model could also shorten the development process of new foods because many virtual foods could be assessed, and discarded if unsuitable, before any physical prototyping is required. The construction and testing of a complete 3D model of mastication presents many challenges including an accurate representation of: the anatomical movements of the oral cavity (including the teeth, tongue, cheeks and palates), the breakdown behaviour of the food, the interactions between comminuted food and saliva as the bolus is formed, the release and transport of taste and aromas and how these physical and chemical processes are perceived by a person. These challenges are discussed in reference to previous experimental and simulation work and using results of new applications of a coupled biomechanical-smoothed particle hydrodynamics (B-SPH) model. The B-SPH model is demonstrated to simulate several complicated aspects of mastication including: (1) the sensitivity of particle size to changes in the movements of the jaw and tongue; (2) large strain behaviour of food due to softening by heating; (3) interactions between solid and liquid food components; (3) the release of tastants into the saliva; and (4) the transport of tastants to the taste buds. These applications show the possibilities of a model to viably simulate mastication, but highlight the many modelling and experimental challenges that remain.

Modified method for preparation of Halubai-an Indian traditional sweet

Halubai, a traditional Indian sweet is conventionally prepared by soaking and grinding whole cereals/millets to a fine paste, straining it through a cloth and cooking the resultant dispersion until it starts gelatinizing. Cooking is continued further with the addition of jaggery water, stirring constantly with intermittent addition of ghee. This process involves many unit operations, which are energy and time consuming. Hence a modified method was developed which is energy efficient and time saving without compromising the quality of the product. One fine fraction (200 mesh, BS) of cereal/millet flours were used in modified method instead of whole cereals. Sensory and instrumental analysis of the samples showed that quality of Halubai prepared using modified method was comparable to that of samples from conventional method. Correlation studies on sensory data of Halubai showed positive relation for the set (r = 0.94) and smoothness (r = 0.84); and negative relation for stickiness (r = -0.94) with the overall quality. Modified method of Halubai preparation which was simple and energy efficient, resulted in products with good sensory quality.

Tongue-mandible coupling movements during saliva swallowing

The purpose of this study was to measure the tongue and mandible positions and displacements in relation to the maxilla in the midsagittal plane to characterize the different saliva swallowing patterns by recording their kinematics. A 2D electromagnetic articulograph using four transducer coils, three attached to the upper surface of the tongue midline plus one attached to the chin anterior part allowed continuous evaluation of tongue and chin movements in twelve young adults in good general health. During 170 s sequences recorded at a frequency of 100 Hz, subjects were at rest, silently reading a text they had chosen. The subjects were free to swallow during the sequence. Deglutition of accumulated saliva was analysed after averaging all values obtained during successive 250 ms periods. We identified three elementary swallowing patterns. Mean duration of tongue-mandible movements were 1·51 ± 0·17 s, 1·63 ± 0·14 s and 2·00 ± 0·08 s for the first, second and third patterns respectively. In the light of other studies based on intra-oral pressure recordings, our results help to understand the tongue-mandible coupling behaviours involved in managing an in-mouth saliva bolus during the three elementary swallowing patterns identified.

The role of oral soft tissues in swallowing function: what can tongue pressure tell us?

Tongue pressure data taken from healthy subjects during normal oral activities such as mastication, speech and swallowing are providing us with new ways of understanding the role of the tongue in craniofacial growth and function. It has long been recognized that the sequential contact between the tongue and the palate plays a crucial role in the oropharyngeal phase of swallowing. However, because the focus of most research on intraoral pressure has been on the generation of positive pressure by the tongue on the hard palate and teeth, generation and coordination of absolute intraoral pressures and regional pressure gradients has remained unexplored. Ongoing research in our laboratory has uncovered highly variable individual pressure patterns during swallowing, which can nonetheless be divided into four stages: preparatory, primary propulsive, intermediate and terminal. These stages may further be sub-classified according to pressure patterns generated at the individual level as tipper or dipper patterns in the preparatory stage, roller or slapper in the primary propulsive and monophasic or biphasic during the intermediate stage. Interestingly, while an increase in bolus viscosity can result in significant changes to pressure patterns in some individuals, it has little effect in others. Highly individual responses to increased viscosity are also observed with swallowing duration. The above, together with other findings, have important implications for our understanding of the aetiology of widely differing conditions such as protrusive and retrusive malocclusions, dysphagia and sleep apnoea, as well as the development of novel food products.

Volatile release and structural stability of β-lactoglobulin primary and multilayer emulsions under simulated oral conditions

The relationship between emulsion structure and the release of volatile organic compounds (VOCs) was investigated using a model mouth system under oral conditions (tongue mastication, artificial saliva, pH and salt). The VOCs were monitored on-line by proton transfer reaction mass spectrometry (PTR-MS). Two types of emulsion system were compared: primary and multilayer oil-in-water (P-O/W, M-O/W) emulsions consisting of soy oil coated by β-lactoglobulin and pectin layers. The P-O/W emulsions showed intensive flocculation at pH 5 and above 200 mM NaCl where the electrostatic repulsive charge was at a minimum. Bridging and depletion flocculation were mostly observed for P-O/W emulsions containing artificial saliva with 1 wt% mucin. The VOC release was found to increase when the emulsion droplets flocculated, thus changing the oil volume phase distribution. The adsorbed pectin layer stabilised the emulsion structure under conditions of short-time oral processing, and hindered the release of hydrophobic VOCs.

Contributory role of the tongue and mandible in modulating the in-mouth air cavity at rest

OBJECTIVES

The tongue-to-palate distance influences the volume of the in-mouth air cavity (IMAC), thus conditioning the entry of aromatic compounds to the olfactory mucosa site. This study was set out to record the IMAC volume by measuring tongue-to-palate distance at rest.

MATERIALS AND METHODS

Twelve young adults in good general health were tested--lips contacting, with at-rest posture of the tongue and jaw during a silent reading task. Observations in this study were limited to pre- and post-swallowing sequences. The tongue-to-palate distance was measured using three electromagnetic sensors placed on the tongue upper surface. IMAC volume was evaluated from a geometrical model, taking into account the tongue-to-palate distance, the IMAC transversal distance measured from dental casts and historic data giving the anterior-posterior distance of the oral cavity.

RESULTS

(1) In the at-rest posture, the tongue-to-palate distance was significantly greater at the posterior sensor level. (2) A vertical shift in tongue posture at rest frequently appeared following deglutition. The upward shifts were of larger amplitude and more frequent than the downward shifts. (3) Evaluation of the IMAC volume gave an approximate value of 12 ml at rest. (4) The chin sensor at rest was 2.8 ± 0.8 mm below its position when in occlusion.

CONCLUSION

The tongue and mandible contribute to shaping the IMAC volume.

CLINICAL RELEVANCE

These and other results suggest that deglutition changes tongue-to-palate distance and influences aroma release during mastication/deglutition acts through modulation of the IMAC volume.

Tongue pressure and oral conditions affect volatile release from liquid systems in a model mouth

The release of volatile organic compounds (VOCs) into the mouth cavity is an integral part of the way flavor is perceived. An in vitro model mouth with an artificial tongue was developed to measure the dynamic release of VOCs from liquid model systems [e.g., aqueous solution, oil, and oil-in-water (O/W) emulsions] under oral conditions. The release of seven selected VOCs was affected by the different polarity and vapor pressure of the compounds and their affinity to the liquid system media. Different tongue pressure patterns were applied to the liquid systems, and the release of VOCs was monitored in real time using proton transfer reaction-mass spectrometry. The release was significantly more intense for longer tongue pressure duration and was influenced by the tongue altering the sample surface area and the distribution of the VOCs. The role of saliva (artificial versus human) and the sample temperature had a significant effect on VOC release. Saliva containing mucin and a higher sample temperature enhanced the release.