Freeze-thaw infusion (FI) is a technique for softening food materials while retaining the shapes. In this study, high-fiber food materials treated with FI were assessed by 65 residents of a special nursing home and a healthcare facility for the elderly. The residents were categorized into four groups based on their usual meal; normal, cut, minced, and blended. These groupings were based on their chewing and swallowing ability. Four kinds of materials treated with FI, bamboo shoots, burdock, lotus roots and carrots, were evaluated for their visual appeal, firmness and ease of swallowing. They were rated on a five-point scale. The materials were valued higher in all three assessment items by the elderly with more disordered chewing and swallowing. Firmness and ease of swallowing were significantly valued highly. The materials were particularly preferred by the people eating minced and blended meals. These results suggest that food materials treated with FI are suitable for the elderly and people with disordered chewing and swallowing. They may be also served as an alternative to minced and blended meals.

Food is crushed between the teeth, and/or between the tongue and palate or oral mucosa in the mouth and a bolus is thus formed with saliva. The present study aimed to determine how the food texture is affected by granularity and the moisture equivalent of food, and if food has a best texture for triggering swallowing.

The materials used in the present study were almond powder with three different granularities (1.4 mm, 600 mm and 500 mm in diameter) and sweet soy powder. The powders were mixed with artificial saliva, distilled water, 0.05% and 0.2% xanthan gum solution, to make an artificial food bolus. The effects of granularity and the moisture equivalent of materials on bolus texture were then investigated. Next, in human subjects, each material was mixed with saliva in the mouth until the subject reached the point of swallowing. Once the subject had decided to swallow, the materials were spat out and the moisture equivalent was measured.

Differences in the concentration of artificial saliva resulted in changes in the food texture. Although the materials showed different patterns of changes in food texture, the textures were similar among the samples when the subject decided to swallow at a certain point of moisture equivalent. Hardness, incohesiveness and adhesion for swallowing ranged between 9,400 and 11,900 N/m², 0.48 and 0.66, and 1,000 and 3,300 J/m³, respectively. However, most subjects could not swallow almond powder of 1.4 mm diameter, even if mixed with saliva, and so this food texture was not plotted in the ranges above.

This study suggested that foods have a range of textures that are applicable for triggering swallowing.

Numerous studies have reported the effectiveness of oral care in the elderly, as well as the association between oral bacteria and aspiration pneumonia. Given that oral bacterial counts constantly change, it is difficult to interpret counts from just one sampling. The purpose of this study was to assess diurnal variations in oral bacterial counts.

Subjects were 36 patients from rehabilitation centers and hospitals in a certain prefecture in Japan who satisfied the following conditions: 1) age of 50 years or older, 2) capable of self-care, 3) capable of gargling for 30 s with 10 ml of sterile physiological saline and expelling it, 4) capable of performing the routine seven times a day; and 5) not having taken any antibiotics for the preceding 3 weeks prior to sampling. Seven samples of oral bacteria were collected in 1 day, each corresponding to the time before and after each of the three meals as well as just before sleep. After gargling for 30 s with sterile physiological saline, a portion of the saline was collected into a test tube to be delivered for examination. We then cultured samples and determined oral bacterial counts (CFU/ml).

Oral bacterial counts were highest before breakfast and lowest after dinner. When bacterial counts were compared before and after each meal, counts after each meal were significantly lower than those before each meal. Moreover, counts significantly increased between the time after each meal and that before the subsequent meal. Bacterial counts were also higher among women than men. We did not find a correlation between bacterial counts and the presence or absence of cerebrovascular diseases. There was also no correlation between bacterial counts and whether or not dentures were worn. Furthermore, bacterial counts were unaffected by the number of remaining teeth. While there was no significant difference in bacterial counts based on whether or not dentures were worn, subjects with dentures did show higher bacterial counts. When diurnal variation in bacterial counts was compared between subjects with or without dentures, those with dentures on average showed higher bacterial counts for all seven data points, suggesting that they may require oral care more than those without dentures.

Taken together, our results revealed that the most influential factor on oral bacterial counts was the particular meal. If the goal is to prevent the development of aspiration pneumonia caused by subclinical aspiration, oral-care just before sleep would be effective.

[Purpose] In recent years, studies have been performed to clarify the swallowing function and causes of eating/swallowing disorders. However, care and clinical practice still involve risks of accidental ingestion/aspiration. We considered that a survey of the status of ingestion/aspiration accidents in a certain area and their detailed evaluation may contribute to prevent cases of suffocation. Therefore, a 3-year questionnaire survey from 2004 to 2007 was performed involving fire department headquarters in the Hanshin region. Accidental swallowing/aspiration cases were extracted from cases of emergency transportation requests, and their contents were evaluated.

[Methods] In the Hanshin district as a bedroom suburb of the metropolitan area, accidental ingestion/ aspiration cases were extracted from cases of emergency transportation requests to fire fighting bureaus/headquarters of each city between 2004 and 2006 and analyzed. The contents of the questionnaire consisted of: (1) the gender, (2) age, (3) severity, (4) time of the incident, and (5) an outline of the incident. Based on collected data, the cases were first classified into accidental ingestion, aspiration, and other cases. This survey was performed in February 2007.

[Results] The mean number of ambulance requests/year was 261.7: accidental ingestion was observed in 15.8%, aspiration in 75.5%, and others in 8.7%. The percentage of aspiration cases significantly differed between males and females. Concerning the age, accidental ingestion was frequently observed in the young group, and aspiration was frequently observed in the group aged ≥ 75 years. The severity of the condition was most frequently mild in both accidental ingestion and aspiration cases. However, the percentages of severe cases and deaths were high in aspiration cases. The most frequent time of the incident was 20:00–21:00 at night in accidental ingestion cases and 12:00–1:00 in the afternoon in aspiration cases. The most frequent substance of accidental ingestion was medical drugs and that of accidental aspiration was bread.

[Discussion] Eating after understanding the food form and food characteristics is an effective method to prevent suffocation. For people living with family members, educational activities such as instruction on what to do in an emergency and methods to relieve suffocation to family members are important.

Contributing to taste perception, digestion and smooth movement of oral organs, saliva plays a major role in all processes from mastication to swallowing. Clinically, patients with low salivary secretion are treated by massaging the salivary glands and oral mucosa, or are asked to conduct tongue, jaw and lip exercises to promote salivary flow. However, these methods are only applicable for patients who are in relatively good mental health. In this study, we examined the effect of odorant stimulation using aromatic oil on promoting salivation, since odorant stimulation can be easily applied to patients who find it difficult to follow instructions and open the mouth.

Forty-three healthy subjects (male: 18, female: 25, mean age: 21.8±1.2 years) without allergic diseases, salivary gland diseases, symptoms of xerostomia, parosmia or smell disorder were selected through screening tests. For odorant stimulation, 100% aromatic oils of black pepper oil (BPO), cardamon oil (CO) and odorless jojoba oil (JO) were used. The aromatic oil was painted on stick-type smelling strips, and then presented at positions 30 mm away from the nostrils of subjects, who were then asked to breathe normally to inhale the odor. Salivary flow rates were measured four times for each subject during inhalation using the cotton method to obtain mean values. To avoid the effects of perceptive factors except for smelling on saliva secretion, the names of odorant samples were presented after testing.

As a result, salivary flow rates significantly increased upon stimulation of BPO (experiment I: 0.164± 0.021 g, experiment II: 0.175±0.026 g) and CO (0.182±0.026 g) relative to resting (experiment I: 0.111± 0.014 g, experiment II: 0.130±0.020 g) and stimulation of JO (0.118±0.018 g). There was no statistical difference in increase of saliva secretion between BPO and CO stimulation. In addition, no gender difference in saliva increase was observed.

BPO is known to activate the insular cortex and shorten the latency of swallowing reflex, and BPO aroma patches have been clinically used for swallowing rehabilitation. In addition, our study revealed that BPO and CO promote salivation. In future, by conducting detailed studies such as changing the frequency and time period of aromatic stimulation, it is suggested that BPO and CO could be used for new oral treatment methods.

[Objective] Rice gruel is the staple food of people with impaired mastication or swallowing; however, its physical properties tend to change at lower temperature. Addition of gelatin to rice gruel is known to inhibit these changes, and yet few studies have reported on the change in characteristics of rice gruel with the addition of gelatin. We therefore decided to determine these changes in the physical properties of rice gruel.

[Method] Rice gruel was prepared by cooking water and raw rice (raw rice : water＝1 : 5) in a rice cooker. Then, we added gelatin dissolved in hot water to the rice gruel. Gelatin is derived from three sources: bovine bone, porcine skin, and fish, and are available with gel strengths of 150 g and 200 g; we used all three types of gelatin with both gel strengths (6 gelatin samples in total). The concentrations of gelatin were 1.0%, 2.0%, and 3.0%. The physical properties of rice gruel immediately after addition of gelatin (0 min), and 30 and 60 min after incubation at 20℃ were measured by a creep meter. Hardness and adhesiveness were determined from the measurements. In the sensory test, we determined the taste, flavor, and ease of swallowing of rice gruel immediately after gelatin was added and 60 min after it was added.

[Results] Changes in hardness and adhesiveness with decreasing temperature were most inhibited in the rice gruel to which 3.0% fish gelatin (gel strength, 150 g) was added. In the sensory test, the rice gruel to which 3.0% fish gelatin (gel strength, 150 g) was added was easy to swallow compared to the control gruel to which gelatin was not added. Moreover, the addition of fish gelatin had hardly any effect on the flavor.

[Discussion] The physical properties of the rice gruel to which fish gelatin was added were hardly affected as the temperature of the rice gruel decreased till it reached room temperature. We think that the increase in hardness and adhesiveness was inhibited because the gelling point of fish gelatin is low, which was also why the ease of swallowing was significantly higher in the case of fish gelatin compared to the control. These results suggest that adding 3.0% fish gelatin (gel strength, 150 g) to rice gruel will be useful for patients with mastication or swallowing disorders who take a long time to eat.

A 41-year-old woman with dysphagia due to Foix-Chavany-Marie syndrome (FCMS). She showed voluntary movement disorder of facial, lingual, pharyngeal, masticatory, and developed anarthria and dysphagia. The voluntary movement of affected muscle was impossible except for only mouth opening but automatic and emotional movement such as laughter or a yawn was preserved (automatic-voluntary-dissociation). Videofluoroscopic examination of swallowing showed impaired oral cavity stage severely and transfer food bolus to the pharynx even in the reclined position of 30-degree and the food inserted in the back of the tongue. We performed passive exercise for affected muscles but voluntary movement did not improve at all. It was impossible that she masticated, but we observed mastication by a jaw and a tongue movement and swallowing saliva in a non-intentional scene. Therefore, we thought that it could use this automatic masticatory movement as process to transfer food bolus to pharynx. We performed sensory input for mastication and rehabilitation to elicit masticatory movement. Stimulation with the spoon which picked up food to push a lower jaw molar tooth part as methods to elicit masticatory movement was effective. Just after this stimulation, a jaw and a tongue rhythmical vertical motion similar to mastication occurred and transferred food bolus to pharynx. As a result of having continued feeding training using this stimulation, use of masticatory movement, placed at 45-degree reclined position, made it possible for the patient to ingest paste food. Continuation of training to induce masticatory movement leads to depression of input threshold of masticatory movement and activation of masticatory CPG and we speculate it contributed to improvement to transfer food bolus to pharynx by masticatory movement.

Four patients exhibited improved airway responsiveness with medical examinations and dysphasia rehabilitation, among cases with poor improvement of symptoms despite early intervention for infantile asthma.

Case 1: A male infant with Down syndrome received the first examination at the age of 1 year and 8 months after being treated for infantile asthma at the age of 10 months without improvement. The patient swallowed chopped food without mastication by tongue thrusting. Counseling on assistance with eating meals was provided. Wheezing was improved and the dose of drug for disease control was tapered.

Case 2: A male infant with unilateral cleft lips did not obtain symptomatic relief following treatment for infantile asthma at the age of 5 months. The first medical examination was at the age of 11 months. The chief complaint was choking during meals. Dysphagia rehabilitation was provided. Airway responsiveness was improved, and the dose of drug for asthma control was tapered.

Case 3: A female infant without underlying diseases had RS virus infection and gastroesophageal reflux disease from 1 month of age. Even after treatment for infantile asthma at 6 months old, there was no symptomatic improvement. Despite counseling on assistance with eating meals from the initial examination at the age of 4 months, counseling methods were not sufficiently complied with at home. The dose of drug for symptom control was not reduced. However, the frequency of seizures progressively decreased.

Case 4: A male infant was first examined at the age of 1 year and 4 months, because symptoms did not improve after taking thickened milk on suspicion of gastroesophageal reflux disease and nasal regurgitation at the age of 4 months and provision of treatment for infantile asthma at the age of 11 months. A tendency to refuse food and dysfunction of mastication were observed. A blowing exercise with a whistle was provided to improve velopharyngeal function failure and counseling on assistance with eating meals was provided. Wheezing and food intake were improved.

Dysphagia due to inappropriate food style and assistance with meals was noted at the first examination in all cases. Three patients exhibited a tendency to refuse food. It appeared that dysphagia rehabilitation can help improve recurrent wheezing in infants with or without underlying diseases, since airway responsiveness with dysphagia rehabilitation was improved and the frequency of asthmatic attacks and doses of drugs for controlling symptoms were reduced. It is suggested that dysphagia examinations should be conducted, given the possibility of dysphasia, in resistant cases of infantile asthma.