The Effect of Taste and Palatability on Lingual Swallowing Pressure

There is evidence that a strong, unpalatable, sour bolus improves swallowing in neurogenic dysphagia. It is not known whether other tastes may alter swallowing physiology. This study investigated the effect of moderate versus high taste concentrations (sweet, sour, salty, bitter) and barium taste samples on lingual swallowing pressure in ten healthy young adults, using a three-bulb lingual pressure array secured to the hard palate. Palatability of the samples was analyzed using the nine-point hedonic scale. Results showed that moderate sucrose, high salt, and high citric acid elicited significantly higher lingual swallowing pressures compared with the pressures generated by water. Pressures in the anterior bulb were significantly higher than those recorded from the middle or posterior bulb. There was no significant effect of palatability on lingual swallowing pressures. High salt and citric acid are known to elicit chemesthesis mediated by the trigeminal nerve. These results suggest that chemesthesis may play a crucial role in swallowing physiology. If true, dysphagia diet recommendations that include trigeminal irritants such as carbonation may be beneficial to individuals with dysphagia. However, before this recommendation more research is needed to examine how food properties and their perception affect swallowing in individuals with and without dysphagia.This research was supported by Syracuse University.     

Soft Palate Movement During Sucking Behavior

To clarify the aspects and role of oropharyngeal closure, soft palate movements during sucking were observed and then assessed by electromyographic and fluoroscopic analyses. Three patterns of sucking movements by the palatoglossus and levator veli palatini muscles were analyzed with electromyographic means in seven healthy adults. Furthermore, a forced sucking maneuver, which required special effort to produce a strong sucking pressure by opening the jaw, was analyzed using lateral fluoroscopy in three of the subjects. During all tested sucking movements, the palatoglossus muscle showed continuous activity. The levator veli palatini muscle did not show remarkable activity during regular air sucking or water sucking when water was held in the oral cavity. However, its participation increased when intraoral sucking pressure was increased by opening the jaw, and lateral fluoroscopic examinations revealed that the soft palate was pulled toward the oral cavity to form a tight contact between the rostral portion of the soft palate and the retrotongue, causing the soft palate to make an L shape. The palatoglossus muscle plays a major role in palatal movement during sucking. Furthermore, the levator veli palatini muscle, whose activity was observed only during high-pressure sucking with an open jaw, may act to maintain tension in the soft palate against strong negative pressure in the oral cavity.     

Pattern of Tongue Pressure on Hard Palate During Swallowing

Contact of the tongue against the hard palate plays an important role in swallowing. This study aimed to clarify the pattern of contact between the tongue and hard palate by analyzing tongue pressure produced in swallowing 15 ml of water by healthy subjects wearing an experimental palatal plate with seven pressure sensors. Tongue pressure was generated initially by close contact with the anteriomedian part of the hard palate, then with the circumferential part, and finally softly with the posteriomedian part. Tongue pressure reached a peak quickly, then decreased gradually before disappearing almost simultaneously at each measured part of the hard palate. Magnitude and duration were significantly larger in the anteriomedian part compared to the other six parts measured, and was significantly smaller in the posteriomedian part. No laterality was found in tongue pressure produced at the circumferential parts of the hard palate. Our findings indicate that the order of tongue contact against each part of the hard palate as well as duration and magnitude of tongue pressure are coordinated precisely during swallowing. These findings could aid assessment of the tongue movement of dysphagic patients during rehabilitation.     

Standard Values of Maximum Tongue Pressure Taken Using Newly Developed Disposable Tongue Pressure Measurement Device

It is clinically important to evaluate tongue function in terms of rehabilitation of swallowing and eating ability. We have developed a disposable tongue pressure measurement device designed for clinical use. In this study we used this device to determine standard values of maximum tongue pressure in adult Japanese. Eight hundred fifty-three subjects (408 male, 445 female; 20-79 years) were selected for this study. All participants had no history of dysphagia and maintained occlusal contact in the premolar and molar regions with their own teeth. A balloon-type disposable oral probe was used to measure tongue pressure by asking subjects to compress it onto the palate for 7 s with maximum voluntary effort. Values were recorded three times for each subject, and the mean values were defined as maximum tongue pressure. Although maximum tongue pressure was higher for males than for females in the 20-49-year age groups, there was no significant difference between males and females in the 50-79-year age groups. The maximum tongue pressure of the seventies age group was significantly lower than that of the twenties to fifties age groups. It may be concluded that maximum tongue pressures were reduced with primary aging. Males may become weaker with age at a faster rate than females; however, further decreases in strength were in parallel for male and female subjects.     

Effects of body position and bolus consistency on the manometric parameters and coordination of the upper esophageal sphincter and pharynx

The development of a solid-state intraluminal sphincter transducer has alleviated many of the problems associated with manometric studies of the upper esophageal sphincter (UES) and pharynx (P). We used this technology to study the effect of position (upright vs. supine) on resting UES pressures and the pressure dynamics of the UES/P complex during both wet and dry swallows in 11 normal volunteers and the effects of foods of different consistencies on the UES/P swallow dynamics in 10 normal volunteers. The UES/P coordination parameters were defined as the 15 time intervals that can be measured between any 2 of 6 pertinent points: the beginning, peak, and end of the pharyngeal contraction and the beginning, nadir, and end of the UES relaxation. Data from both the circumferential transducer used to measure sphincter pressures and a standard microtransducer used to measure pharyngeal pressures were collected on-line by an Apple IIe microcomputer and analyzed by programs written in our laboratory. Significant changes in swallow coordination were measured between upright and supine swallows of the same bolus size, between wet and dry swallows in the same position, and among foods of varying consistencies. Resting UES pressure was unchanged by position and pharyngeal contraction pressure was unchanged by bolus size or consistency.     

Nonsurgical treatment of drooling in a patient with closed head injury and severe dysarthria

The purpose of this investigation was to measure the effectiveness of the antimuscarinic drug atropine sulfate in the treatment of chronic drooling in a patient with a history of severe closed head injury and resultant widespread oral neuromuscular and higher cortical disturbances. Results of the A-B-A-B-A-B withdrawal paradigm, chosen to demonstrate the functional relationship between drug therapy and the degree of drooling, revealed that administration of atropine sulfate reduced by more than 50% of baseline levels the amount of resting secretion, intraoral accumulation, and pharyngeal-laryngeal pooling of saliva, with negligible side effects. These results are discussed and compared to the alternative drug and surgical approaches to the alternative drug and surgical approaches to treatment that have been the primary focus of recent research on drooling.     

Tongue Pressure Patterns During Water Swallowing

Bolus propulsion during the normal oral phase of swallowing is thought to be characterised by the sequential elevation of the front, middle, and posterior regions of the dorsum of the tongue. However, the coordinated orchestration of lingual movement is still poorly understood. This study examined how pressures generated by the tongue against the hard palate differed between three points along the midline of the tongue. Specifically, we tested three hypotheses: (1) that there are defined individual patterns of pressure change within the mouth during liquid swallowing; (2) that there are significant negative pressures generated at defined moments during normal swallowing; and, (3) that liquid swallowing is governed by the interplay of pressures generated in an anteroposterior direction in the mouth. Using a metal appliance described previously, we measured absolute pressures during water swallows in six healthy volunteers (4 male, 2 female) with an age range of 25–35 years. Participants performed three 10-ml water swallows from a small cup on five separate days, thus providing data for a total of 15 separate water swallows. There was a distinct pattern to the each of the pressure signals, and this pattern was preserved in the mean obtained when the data were pooled. Furthermore, raw signals from the same subjects presented consistent patterns at each of the five testing sessions. In all subjects, pressure at the anterior and hind palate tended to be negative relative to the preswallow value; at mid–palate, however, pressure changes were less consistent between individuals. When the pressure differences between the sites were calculated, we found that during the swallow a net negative pressure difference developed between anterior and mid-palate and a net positive pressure difference developed between mid-palate and hind palate. Large, rapid fluctuations in pressure occurred at all sites and these varied several-fold between subjects. When the brief sharp reduction in pressure that occurred early in each swallow was used to determine the sequence of events, we found that activity occurred first at the anterior of the palate followed by the mid-palate and then the hind palate. There was a considerably longer and more variable delay between the start of activity at the front of the palate than at the rear of the palate. To obtain an index of the “effort” involved in generating the pressures at each site regardless of direction (positive or negative), we obtained the product of the root mean square (RMS) pressure change during each swallow (kPa) and its duration (s). Overall, the most effort appears to have occurred at the front of the palate and the least at mid-palate. Our results also showed that some participants exerted a small amount of midline pressure when swallowing, while others used a relatively large amount of tongue pressure. We conclude that while tongue behaviour during swallowing follows a classical sequence of rapid shape changes intended to contain and then propel the bolus from the oral cavity to the pharynx, there is a large range of individual variability in how this process is accomplished.     

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.     

The effects of lingual exercise on swallowing in older adults

OBJECTIVES: To determine the effects of an 8-week progressive lingual resistance exercise program on swallowing in older individuals, the most "at risk" group for dysphagia. DESIGN: Prospective cohort intervention study. SETTING: Subjects were recruited from the community at large. PARTICIPANTS: Ten healthy men and women aged 70 to 89. INTERVENTION: Each subject performed an 8-week lingual resistance exercise program consisting of compressing an air-filled bulb between the tongue and hard palate. MEASUREMENTS: At baseline and Week 8, each subject completed a videofluoroscopic swallowing evaluation for kinematic and bolus flow assessment of swallowing. Swallowing pressures and isometric pressures were collected at baseline and Weeks 2, 4, and 6. Four of the subjects also underwent oral magnetic resonance imaging (MRI) to measure lingual volume. RESULTS: All subjects significantly increased their isometric and swallowing pressures. All subjects who had the MRI demonstrated increased lingual volume of an average of 5.1%. CONCLUSION: The findings indicate that lingual resistance exercise is promising not only for preventing dysphagia due to sarcopenia, but also as a treatment strategy for patients with lingual weakness and swallowing disability due to frailty or other age-related conditions. The potential effect of lingual exercise on reducing dysphagia-related comorbidities (pneumonia, malnutrition, and dehydration) and healthcare costs while improving quality of life is encouraging.     

Monitoring of Pharyngeal and Upper Esophageal Sphincter Activity with an Arterial Dilation Balloon Catheter

In patients with dysphagia and radiologic signs of dysfunction of the upper esophageal sphincter (UES), manometry is helpful in giving a better understanding of muscular activity during swallowing. Traditional manometric methods include use of perfusion catheters or solid-state intraluminal strain gauges. The rapid and asymmetric pressure variations in the UES and difficulties compensating for the pharyngolaryngeal elevation during swallowing limit the value of these methods. We used an arterial balloon dilation catheter as a probe in manometric recording of the UES in 28 healthy volunteers. Simultaneous perfusion manometry of the pharynx with the same catheter was performed to assess the coordination of the muscular activity in the esophageal entrance during swallowing. The catheter was well tolerated by all subjects. We found an average resting pressure in the UES of 31.0 mmHg, and the average maximum pressure during contraction was 89.0 mmHg. The average duration of the swallowing act was 3.9 s. All subjects displayed a complete UES relaxation and a normal coordination of propagated pressure in the hypopharynx and UES. The results were highly reproducible and the interindividual range was low. Arterial dilation catheters are safe and have suitable physical properties for pressure monitoring in the UES.     

Age-Related Differences in Pressures Generated During Isometric Presses and Swallows by Healthy Adults

The aim of this prospective observational study was to determine the associations among age, maximum lingual isometric pressures, and maximum swallow pressures in specific regions of the tongue. Individuals 21 years and older who reported normal swallowing were enrolled. Seventy-one healthy adults were stratified by age into young (21–40 years), middle (41–60), and old (61–82) groups. Maximum pressures were measured for each individual during isometric tongue press tasks as well as saliva, 5, and 10 mL thin liquid bolus swallows at 5 sensors located on the hard palate: front, middle, left, right, and back. Lower maximum lingual pressures for all tasks were associated with increased age (p < 0.04). Saliva pressures exhibited a different pressure pattern than bolus swallows with pressures higher than bolus swallows on middle (p < 0.03) and back (p < 0.05) tongue sensors but not in the front. Diminished swallow pressure reserve (maximum isometric pressure–maximum swallow pressure) also was found with increased age (p < 0.03). Isometric pressures were greater than swallow pressures in young and middle age groups at both the front (p < 0.04) and back (p < 0.03) sensors, but only significantly greater at the front sensor for the oldest group (p < 0.04). Older healthy adults have lower lingual isometric pressures and lower swallow pressures than younger healthy adults. Elders have a decreased swallow pressure reserve to draw upon during occasions of physiological stress. While the exact mechanisms for age-related decline in lingual pressures remain unclear, they are likely due, at least in part, to sarcopenia. Saliva, 5, and 10 mL thin boluses also exhibit different age-related declines in pressure at specific sensors, indicating they may elicit different muscle activation patterns.     

Quantitative measurement of fixation rate and dimension changes in the aldehyde/pressure-fixed canine carotid artery

Excised canine carotid arteries held at constant physiologic length were cycled from -13 to +27 kPa with a constant-flow infusion pump, and the pressure-volume curves were recorded. The change in diameter on reducing the pressure from 16 to 0 kPa was determined and the strain of recoil [(diameter16--diameter0)/diameter16] calculated. Diameter recoil was reduced from 51% (fresh tissue) to 5% after 3 h pressure fixation in 4% formaldehyde and to 9% after 15 min in 2% glutaraldehyde with little further change. Lengthwise recoil was reduced from 37 to 10% after 5 min in 2% glutaraldehyde. Photographs were taken to measure outer diameter during pressure fixation. There was no change in diameter in either fixative from the first minute up to 3 days at the constant pressure of 16 kPa.     

Simultaneous videoradiography and pharyngeal solid state manometry (videomanometry) in 25 nondysphagic volunteers

Recent technological advances in manometry, including solid state transducers and computerized analysis, allows for reliable interpretation of intraluminal pharyngeal pressures. Simultaneous videoradiography (barium swallow) provides fluoroscopic control of the manometric sensors (videomanometry), thereby eliminating the uncertainty of sensor dislocation during laryngeal elevation. This is the first study describing normal manometric parameters in videomanometry during barium swallow. Seven manometric parameters and six videoradiographic parameters were analyzed. We included 25 nondysphagic volunteers with normal videoradiographic parameters in the study. The examination was performed in an upright physiologic position during 10-ml barium and dry swallows. Mean resting pressure in the upper esophageal sphincter was 89.6±32.6 (±2 SD) mmHg. Mean residual pressure during relaxation of the upper esophageal sphincter was 7.2±8.0 (±2 SD) mmHg during barium swallow and 3.8±6.2 (±2 SD) mmHg during dry swallow. The mean duration of upper esophageal sphincter relaxation was 601±248 (±2 SD) msec. The mean peristaltic contraction of the upper esophageal sphincter was 253.8±142.8 (±2 SD) mmHg. Fourteen (56%) of the 25 had a measurable intrabolus pressure (mean 33.2±17.3 mmHg) at the level of the inferior pharyngeal constrictor. A specific finding was discovered when the epiglottis tilts down hitting the manometric sensor. This epiglottic tilt was identified in 7 subjects (28%) and caused pressures of around 600 mmHg. A standardized manometric technique is important in videomanometry, and normal values as described in this study are essential in clinical use.     

Involvement of Sensory Input from Anterior Teeth in Deglutitive Tongue Function

Swallowing is a reflex that receives sensory information from the peripheral nerves and from the cerebral cortex. The aim of the present study was to investigate whether the sensory input from anterior teeth affects the functional characteristics of tongue pressure applied against the hard palate during swallowing. Subjects were eight healthy volunteers. Tongue pressure against the hard palate during swallowing 10 ml of water was measured under two conditions: preanesthesia and postanesthesia of anterior teeth. The sensory deprivation of anterior teeth was performed by periodontal anesthesia. Tongue pressure was measured using a multiple tactile array sensor (MTAS) with eight sensor channels arranged in tandem. The duration of the tongue pressure production during swallowing was increased under periodontal anesthesia. In addition, the maximum tongue pressure and the pressure integral during swallowing were decreased under periodontal anesthesia, in particular at the anterior region of the palate. These findings indicate that sensory input from anterior teeth, including periodontal mechanoreceptor, affects the deglutitive tongue pressure and duration and provides peripheral feedback to modulate some aspects of the neurophysiologic control of deglutitive tongue movement.     

Tongue Pressure During Swallowing in Adults with Down Syndrome and Its Relationship with Palatal Morphology

In individuals with Down syndrome, hypotonicity of the tongue and an underdeveloped maxilla may lead to poor oral motor coordination, which adversely affects the oral phase of swallowing. This study aimed to evaluate the characteristics of pressure produced by the tongue against the hard palate during swallowing in individuals with Down syndrome. In addition, the relationship between tongue pressure and palatal morphology was examined. We studied nine adults with Down syndrome and ten healthy adults as controls. Tongue pressure while swallowing 5 mL water was recorded by a sensor sheet system with five measuring points attached to the hard palate. Palatal length, depth, width, curvature, and slope were measured by three-dimensional digital maxillary imaging. The order of onset of tongue pressure on the median line of the hard palate was the same in all participants, except for three with Down syndrome. The duration and maximal magnitude of tongue pressure on the median line in nine participants with Down syndrome were significantly shorter and lower than those of controls. In participants with Down syndrome, significant positive correlations were observed between the duration of tongue pressure at the mid-median part of the hard palate and palatal depth and width, and between the duration and maximal magnitude of tongue pressure at the posterior-median part and palatal length. These findings suggest that impaired tongue activity, poor tongue control, and constrained tongue motion due to a short and narrow palate contribute to swallowing difficulty in individuals with Down syndrome.     

The influence of bolus volume and viscosity on anterior lingual force during the oral stage of swallowing

The influence of bolus volume and viscosity on the distribution of anterior lingual force during the oral stage of swallowing was investigated using a new force transducer technology. The maximum force amplitudes from 5 normal adults were measured simultaneously at the mid-anterior, right, and left lateral tongue margins during 10 volitional swallows of 5-, 10-, and 20-ml volumes of water, applesauce, and pudding. Results indicated significant increases in peak force amplitude as viscosity increased. Volume did not significantly influence maximum lingual force amplitudes. Individual subjects demonstrated consistent patterns of asymmetrical force distribution across the lingual margins tested. The results suggest that bolus-specific properties influence the mechanics of oral stage lingual swallowing. This finding has important clinical implications in the assessment and treatment of dysphagic individuals.     

Standardized Instrument for Lingual Pressure Measurement

Disease-related atrophy of the tongue muscles can lead to diminished lingual strength and swallowing difficulties. The devastating physical and social consequences resulting from this condition of oropharyngeal dysphagia have prompted investigators to study the effects of tongue exercise in improving lingual strength. We developed the Madison Oral Strengthening Therapeutic (MOST) device, which provides replicable mouth placement, portability, affordability, and a simple user interface. Our study (1) compared the MOST to the Iowa Oral Performance Instrument (IOPI), a commercial pressure-measuring device, and (2) identified the optimal tongue pressure sampling rate for isometric exercises. While initial use of the MOST is focused on evaluating and treating swallowing problems, it is anticipated that its greatest impact will be the prevention of lingual muscle mass and related strength diminishment, which occurs even in the exponentially increasing population of healthy aging adults.     

Swallowing Apraxia: A Disorder of the Praxis System?

The purpose of this review is to evaluate the disorder of swallowing apraxia and determine how it fits into the praxis system. Swallowing apraxia, a proposed disorder of lingual, labial, and mandibular coordination, has been observed before bolus transfer during the oral stage of swallowing. Although frequently discussed anecdotally in dysphagia literature, the possible mechanisms and neural networks of swallowing apraxia have not been elucidated. Similarities and differences of swallowing apraxia with buccofacial, speech, and limb apraxias are evident. Critical review of the literature has identified possible similarities as greater occurrence upon command, transitive nature of the action, and evidence of spatial errors. Conversely, differences such as hemispheric lateralization and multiple gesture assessment may exist between swallowing apraxia and more traditional forms of apraxia. Until discrete error patterns of swallowing apraxia are identified and precisely measured, the nature of this disorder and its relationship with the praxis system will continue to remain elusive.