Tongue pressure generation during tongue-hold swallows in young healthy adults measured with different tongue positions.

Tongue-hold swallow (THS) has the potential to be a resistance exercise not only for the pharyngeal constrictor but for the tongue muscles. To elucidate the physiological mechanisms of THS, this study investigated intraoral pressure generation during THS in relation to different extents of tongue protrusion. Tongue pressure was measured by a 5-point pressure sensor sheet placed onto the hard palate of 18 healthy young subjects who performed three swallow tasks: normal dry swallow, THS with slight tongue protrusion, and THS with greater tongue protrusion. Subjects randomly repeated each task five times. Maximum range of tongue protrusion was also measured in each subject to estimate lingual flexibility. With an increase in the extent of tongue protrusion, pressure generation patterns became irregular and variable. Duration of pressure generation increased with statistical significance in the posterior circumferential parts of the hard palate (p < 0.05). Maximal magnitude and integrated value of the pressure recorded at these locations increased in eight subjects as the extent of tongue protrusion increased, but it decreased in nine. The former group showed greater lingual flexibility, while the latter group exhibited less flexibility. THS may place different amounts of load on the tongue muscles by adjusting the degree of tongue protrusion.

Effect of the effortful swallow and the Mendelsohn maneuver on tongue pressure production against the hard palate.

Although effortful swallow and the Mendelsohn maneuver are commonly used in dysphagia rehabilitation, little is known about their effects on tongue-palate pressure production. The purpose of this study was to investigate the effects of effortful swallow and the Mendelsohn maneuver on tongue pressure production. Fourteen healthy volunteers (10 men, 4 women; age range = 21-41 years) participated. Tongue pressures during dry swallow, water swallow, effortful swallow, and the Mendelsohn maneuver were measured using a sensor sheet system with five measurement points on the hard palate. Sequential order, duration, maximal magnitude, and the integrated value of tongue pressure at each measurement point were compared among the four tasks. Onset of tongue pressure at the posterior-circumferential parts occurred first in the Mendelsohn maneuver; that at the anterior-median part was earlier than at other parts in the effortful swallow. At all measurement points, tongue pressure duration was significantly longer in the Mendelsohn maneuver than in other tasks. Effortful swallow was most effective in increasing tongue pressure. The integrated value of tongue pressure at the posterior-circumferential parts in the Mendelsohn maneuver and at the median parts in the effortful swallow showed a tendency to increase. These results suggest that tongue pressure increases along a wide part of the hard palate in effortful swallow because the anchor of tongue movement is emphasized at the anterior part of the hard palate. The Mendelsohn maneuver provides prolonged and accentuated tongue-palate contact at the posterior-circumferential parts, which might be important for hyoid-laryngeal elevation during swallowing.

Effect of lingual plates on generating intra-oral pressure during swallowing: an experimental study in healthy subjects.

BACKGROUND: Although palatal augmentation prostheses (PAPs) can improve dysphagia, their application is compromised in the absence of maxillary abutment teeth. Experimental lingual plates (ELPs) used for raising the tongue may be employed as alternative to PAPs. METHODS: Influence of different ELP designs, plateau (P-type) and drop-shaped (D-type), on the intra-oral pressure during swallowing were tested. Eleven healthy dentate volunteers, with a mean age of 35.5±10.5 years, participated in this study. Tongue pressure on the hard palate was measured using an ultra-thin sensor sheet with five measuring points, whilst performing dry, 5-ml and 15-ml water swallows, with and without the ELPs in situ. Additional pressure sensors were installed in the lingual aspects of the ELPs, and on the vestibular aspect of the lower molars for measuring sublingual and oral vestibule pressures, respectively. Each measurement was recorded thrice. A repeated measures ANOVA was employed to verify differences in duration, maximal magnitude and integrated value for the different experimental situations. Tukey's post hoc test was performed for comparison testing. Statistical significance was set at p<0.05. RESULTS: The sequence of tongue-palate contact on the median line of the hard palate without ELPs was maintained, except for the 15 ml P-type swallow. Tongue pressure started earlier with the D-type but reached its peak nearly at the same time as without ELPs. The peak magnitude and cumulative tongue pressure against the hard palate decreased by wearing ELPs (p<0.05), but was inconsistent between the two types of ELPs and for the different swallowing volumes. Both, maximum and cumulative vestibular pressures were mostly similar or larger with P-type than that with D-type. CONCLUSION: D-type and P-type ELPs seem to have the inverse effect of PAPs on the palatal tongue pressure during swallowing. These first counterintuitive findings do not yet justify rejecting the basic rationale of using ELPs for the treatment of dysphagia; hence a rather biologically designed piezographic lingual plate may be more appropriate.

Tongue pressure modulation for initial gel consistency in a different oral strategy.

BACKGROUND: In the recent hyper-aged societies of developed countries, the market for soft diets for patients with dysphagia has been growing and numerous jelly-type foods have become available. However, interrelationships between the biomechanics of oral strategies and jelly texture remain unclear. The present study investigated the influence of the initial consistency of jelly on tongue motor kinetics in different oral strategies by measuring tongue pressure against the hard palate. METHODS: Jellies created as a mixture of deacylated gellan gum and psyllium seed gum with different initial consistencies (hard, medium or soft) were prepared as test foods. Tongue pressure production while ingesting 5 ml of jelly using different oral strategies (Squeezing or Mastication) was recorded in eight healthy volunteers using an ultra-thin sensor sheet system. Maximal magnitude, duration and total integrated values (tongue work) of tongue pressure for size reduction and swallowing in each strategy were compared among initial consistencies of jelly, and between Squeezing and Mastication. RESULTS: In Squeezing, the tongue performed more work for size reduction with increasing initial consistency of jelly by modulating both the magnitude and duration of tongue pressure over a wide area of hard palate, but tongue work for swallowing increased at the posterior-median and circumferential parts by modulating only the magnitude of tongue pressure. Conversely, in Mastication, the tongue performed more work for size reduction with increasing initial consistency of jelly by modulating both magnitude and duration of tongue pressure mainly at the posterior part of the hard palate, but tongue work as well as other tongue pressure parameters for swallowing showed no differences by type of jelly. CONCLUSIONS: These results reveal fine modulations in tongue-palate contact according to the initial consistency of jelly and oral strategies.

Tongue pressure during swallowing is decreased in patients with Duchenne muscular dystrophy.

Although dysphagia is a life-threatening problem in patients with Duchenne muscular dystrophy (DMD), the pathophysiology of oral stage dysphagia is yet to be understood. The present study investigated the tongue motor deficit during swallowing in patients with DMD and its relationship with disease-specific palatal morphology. Tongue pressure during swallowing water was recorded in 11 male patients with DMD and 11 age- and sex-matched healthy subjects using an intra-oral sensor with five measuring points, and the state of tongue pressure production was compared between the groups. Palatal morphology was assessed by a non-contact three-dimensional scanner on maxillary plaster models. In patients with DMD, the normal sequential order of tongue-palate contact was lost and the maximal magnitude and integrated value of tongue pressure on the mid-anterior part of palate were smaller than those in healthy subjects. The width of the palate in patients was greater than that in healthy subjects and the depth of the palate in patients had a negative correlation with tongue pressure magnitude on the median palate. Our results suggested that the deteriorated tongue motor kinetics prevented tongue movement during swallowing that was appropriate for the depth of the palate and affects the state of tongue pressure production during swallowing.

Newly developed sensor sheet for measuring tongue pressure during swallowing.

PURPOSE: The aim of this study was to develop a sensor sheet for measuring tongue pressure during swallowing and to clarify its usefulness by comparing it with a conventional pressure sensor installed in the palatal plate. METHODS: A tactile sensor system was used for the construction of the measuring system. Based on our preceding study, a T-shaped sensor sheet with 0.1mm thickness, five measuring points (three points on the median line, two points on the posterior-lateral part) and three sizes based on the morphological analysis of 60 maxillary casts was designed for application on the hard palate. To elucidate the sensing characteristics of the sensor sheet, the output level of the sensor sheet was compared with that of a conventional pressure sensor under the same load. The maximal magnitude of tongue pressure (MP) during the swallowing of 15 ml water was recorded by a sensor sheet attached to the palatal mucosa and was compared with that recorded by pressure sensors installed in the palatal plate. RESULTS: The output level of the sensor sheet was smaller than that of the pressure sensor. There was a high correlation between the output levels of the two sensors (R=0.952, P<0.001). Although MP at each sensing point of the sensor sheet was also smaller than that recorded by the pressure sensors, MP collected by the regression equation obtained in our experiment was quite similar to that for the pressure sensors. CONCLUSIONS: This system could be useful for evaluating tongue activity during oropharyngeal swallowing.