The importance of taste on swallowing function.

The world's population is aging. Pneumonia is the leading cause of death among the older adults, with aspiration pneumonia being particularly common. Aspiration pneumonia is caused by a decline in swallowing function. Causes can include age-related sarcopenia of swallowing muscles, cognitive decline, cerebrovascular and other diseases or even changes in individual taste preference. Currently, the main treatment approach for dysphagia is resistance training of swallowing-related muscles. This approach has not been effective and establishment of novel methods are required. In this review, we introduce and discuss the relationship between taste, taste preference, carbonation and swallowing function. Taste and preference improve swallowing function. Recently, it has been shown that a carbonated beverage that combines the functionality of a thickening agent, the appeal of taste, and the stimulation of carbonation improves swallowing function. This may be very useful in the recovery of swallowing function. It is important to note that deliciousness is based not only on taste and preference, but also on visual information such as food form. Umami taste receptors are expressed not only in taste buds but also in skeletal muscle and small intestine. These receptors may be involved in homeostasis of the amino acid metabolic network, i.e., the process of amino acid ingestion, intestine absorption, and storage in skeletal muscle. Proper stimulation of umami receptors in organs other than taste buds may help maintain nutritional status and muscle mass. Umami receptors are therefore a potential therapeutic target for dysphagia.

Effects of Visual-Motor Illusion via Image Videos Showing Increased Exercise Intensity on the Tibial Anterior during Sit-to-Stand Movement: A Study of Healthy Participants.

Visual-motor illusion (VMI) elicits kinesthetic sensation from visual stimulation. We have previously performed ankle motion VMI with resistance applied to the ankle joint on the paralyzed side (power-VMI (P-VMI)) and ankle motion VMI without resistance (standard-VMI (S-VMI)) to activate the tibialis anterior (TA) muscle in stroke-paralyzed patients and compared sit-to-stand (STS) durations, but these studies did not measure TA activity during the STS movement. The purpose of this study was to evaluate the effects of different intensities of visual stimuli presented during VMI on TA and STS movement. Healthy right-footed adults (n = 18) observed two different VMI videos of ankle dorsiflexion, including S-VMI and P-VMI, with an observation time of 2 min each. STS movement was evaluated before and after watching each video. Each participant performed both S-VMI and P-VMI interventions on the same day. Only P-VMI enhanced the integrated electromyogram of the TA, increased the angular velocities of the trunk forward inclination and the ankle dorsiflexion, and shortened the STS duration. Our results indicate that P-VMI facilitates the activation of TA during STS, and we believe that we have clarified the intervention mechanism of VMI.

Effects of carbonated beverages on sustained swallowing behavior changes in older inpatients.

Sensory stimulation, including stimulation with carbonated liquids, has been known to influence swallowing activity. The aim of this study is to determine the effect of sustained changes in the swallowing behavior of hospitalized patients without dysphagia using the cervical auscultatory recordings of swallowing sounds. The study participants were hospitalized older adults without dysphagia. The participants were asked to initially swallow water and then a carbonated beverage. The sustained effects of the carbonated beverage in relation to swallowing movements were evaluated by measuring the swallowing sounds at the following time periods: (1) immediately and (2) at 1 to 9 min with intervals of 2 min after swallowing the carbonated beverage. The swallowing sounds before and after swallowing the same volume of water were also measured and compared on a different day. Analysis was performed to calculate the time from a sound signal to the beginning of the swallowing sound. Significant shortening of the swallowing sound time of the late pharyngeal phase was observed up to 7 min after swallowing the carbonated beverage, except during the 3 min after swallowing. Shortening of the whole swallowing sound time was observed only immediately after swallowing the carbonated beverage. Regarding the shortening of the acoustic signal in the late pharyngeal period, the effect of cerebral excitability changes due to carbonic acid stimulation was considered.

Effects of visual-motor illusions with different visual stimuli on the sit-to-stand of people with hemiplegia following stroke: A randomized crossover controlled trial.

BACKGROUND: The objective of this study was to determine the effects of different visual stimuli during visual-motor illusion on sit-to-stand in people with hemiplegia following stroke. METHODS: This was a randomized crossover controlled trial. Twenty people with hemiplegia following stroke were randomly divided into groups. The video images used for visual-motor illusion were ankle dorsiflexion without resistance (standard visual-motor illusion [standard illusion]) and maximum effort dorsiflexion with resistance (power visual-motor illusion [power illusion]). People with hemiplegia following stroke underwent both illusion interventions with a 1-week washout period in between; group A started with the standard illusion intervention and group B started with the power illusion intervention. Outcomes included the sit-to-stand duration, maximum weight-bearing value, trunk movement during sit-to-stand, ankle joint movement during sit-to-stand, and active ankle dorsiflexion movement on the paralyzed side. RESULTS: The angular velocity of the trunk and ankle joints increased significantly during sit-to-stand, and sit-to-stand duration decreased significantly in response only to power illusion. In addition, the change in angular velocity of active ankle dorsiflexion was significantly greater in response to power illusion than was the change in response to standard illusion. CONCLUSION: Power illusion induces a greater improvement in paralyzed ankle dorsiflexion function than standard illusion, resulting in shorter sit-to-stand duration.

Effects of visual-motor illusion in stroke hemiplegic patients with left-side personal neglect: A report of two cases.

Personal neglect is the neglect of self-body space, which often occurs in patients with unilateral spatial neglect (USN), but lacks a dedicated rehabilitation. The purpose of this study was to investigate the effects of visual-motor illusion (VMI) on two-stroke hemiplegic patients with left-side personal neglect. Case 1 was a 53-year-old man diagnosed with a right lenticulostriate artery infarction. Case 2 was a 76-year-old woman diagnosed with a right middle cerebral artery infarction. USN symptoms were not observed in either patient in the desk USN assessment, but personal neglect and USN symptoms in daily life were observed in both patients. Intervention effects were verified using an ABA design, comprising a 5-day three-phase (A1, B, A2). In phase B, VMI was performed on the paralyzed upper limb for 10 min in addition to conventional physical therapy. Outcomes measures were the Fluff test, Catherine Bergego Scale (CBS), Fugl-Meyer Assessment (FMA), and Functional Independence Measure (FIM). In both patients, no improvements were noted in FMA, but improvements were observed in the Fluff test, CBS, and FIM in phase B; these effects were retained in phase A2. Therefore, VMI may have contributed to improvements in Personal neglect and USN symptoms in daily life.

Effects of Carbonated Thickened Drinks on Pharyngeal Swallowing with a Flexible Endoscopic Evaluation of Swallowing in Older Patients with Oropharyngeal Dysphagia.

This study aimed to determine the efficacy of carbonated and sweetened drinks added to thickened liquids, which are routinely used for patients with dysphagia to improve dysphagia. Patients swallowed thin liquid (Thin), thickened liquid (Thick), carbonated thin drink (C-Thin), and carbonated thickened drink (C-Thick) in random order. Penetration and/or aspiration were scored using the Penetration−Aspiration Scale (PAS). The residue was scored using the Yale Pharyngeal Residue Severity Rating Scale (YPR-SRS). Swallowing reflex initiation was scored using the Hyodo score. The subjective difficulty of swallowing was scored on a face scale. We analyzed 13 patients with a mean age of 79.6 ± 9.6 years. PAS was significantly lower in the C-Thick group than the Thin group (p < 0.05). Swallowing reflex initiation was significantly different between the Thin and Thick (p < 0.01) groups; moreover, post hoc analysis revealed that it was significantly lower in the C-Thick group than the Thin group (p < 0.01). The subjective difficulty of swallowing in the C-Thick was significantly lower than the Thick group (p < 0.05). C-Thick was easier to swallow than Thick and may improve penetration and/or aspiration in older patients with dysphagia with complex diseases.

Effects of Action Observation Therapy with Limited Visual Attention on Walking Ability in Stroke Patients.

In this study, we compared the effects of action observation therapy (AOT) on the walking ability of stroke patients between videos with limited visual attention (body part videos) and a video with the whole body (whole body video). We employed a crossover design and conducted 3 AOT sessions (body part videos, whole body video and a scenery video) for 11 stroke patients. The evaluation items were the 10-m walking time and number of steps, cadence, trunk and knee joint angles during walking, and the timed up and go test (TUGT). After body part videos, the 10-m walking time, trunk and knee joint angles and TUGT significantly improved, suggesting them to be an efficient AOT method.

Relationship between oral function and life-space mobility or social networks in community-dwelling older people: A cross-sectional study.

OBJECTIVES: This study aimed to clarify the relationship between oral function and life-space mobility or social networks in order to explore approaches that prevent a decline in oral function. MATERIALS AND METHODS: A total of 113 community-dwelling older people (mean age; 75.7 ± 7.3 years) who participated in preventive long-term care projects aimed at the maintenance or improvement of physical and mental functions were included in this study. The life-space assessment (LSA) was used to evaluate life-space mobility, while the Lubben Social Network Scale-6 (LSNS-6) was employed to assess social networks. Oral function was measured by maximum voluntary tongue pressure, oral diadochokinesis, the repetitive saliva swallowing test, and lip pressure. Indices of frailty were grip strength and the Kihon Checklist score. Multiple regression analysis was performed to clarify whether the LSA, LSNS-6, and frailty are associated with oral function. RESULTS: The results of the Kihon Checklist showed that 63 participants (56%) were subjectively and at least slightly aware of a decline in oral function. LSA (B = 0.222, p < .001) and grip strength (B = 0.266, p = .003) associated with maximum voluntary tongue pressure. The goodness of fit of the predictive model was an adjusted R2 value of .486. Other oral functions were not associated with any factors and the goodness of fit of the model was poor (Adjusted R2 < .1). LSNS-6 was not associated with any oral function. CONCLUSIONS: Life-space mobility and grip strength were independent factors associating maximum voluntary tongue pressure, while social networks did not directly association oral function. This study suggests the necessity of a program that approaches both oral and physical functions through guidance for securing a certain amount of daily activity for older people at risk of or exhibiting a decline in maximum voluntary tongue pressure.

Effects of gait training with non-paretic knee immobilization on patients with hemiplegia: Three single-case studies.

Patients' with a hemiplegic gait and difficulties with activities of daily living may improve through intensive training of their paretic lower limbs. This study examined the possibility of improving their gait by immobilizing the non-paretic knee joint in extension and promoting weight shift toward the paretic side. Single-case ABABA studies were conducted, involving three patients with hemiplegia. The patients walked with their non-paretic knee joints immobilized in extension using a dial-lock knee orthosis during the intervention (B1 and B2) periods. Measurement items included (1) temporal and distance factors and (2) hip, knee, and ankle joint angles during gait. In all subjects, the stance phase was significantly prolonged on the paretic side during all intervention periods following the first baseline (A1) period. In Subject 1, hip extension in the stance phase improved during all intervention periods following the A1 period, and, in Subjects 2 and 3, the knee hyperextension in the stance phase, which was observed during the A1 period, was resolved during the second (A2) and third (A3) baseline periods. Gait training with non-paretic knee immobilization may promote weight shift toward the paretic side to overcome a swing limitation on the immobilized side, consequently providing an opportunity for training in weight bearing for the paretic limb and an improved, more symmetrical gait pattern.

Antidepressant-Like Effect of 1α-Hydroxyvitamin D3 on Mice in the Forced Swimming Test.

We examined the effect of 1α-hydroxyvitamin D3 [1α(OH)D3] on mice in the forced swimming test. Intragastric administration of 1.0 µg/kg of 1α(OH)D3 reduced immobility time in the forced swimming test. At all concentrations tested (0.5, 1.0, 2.0 µg/kg), 1α(OH)D3 had no effect on locomotor activity, compared with controls. These results suggest that 1α(OH)D3 may have antidepressant-like activity.

Effect of carbonated beverages on pharyngeal swallowing in young individuals and elderly inpatients.

Gustatory and chemical stimulations of the oral cavity and pharyngeal mucosa by carbonated water improve pharyngeal swallowing. We compared changes in pharyngeal swallowing and sensory aspects induced by a carbonated beverage preferred by Japanese with those induced by carbonated water, a sports drink, and tap water in healthy young subjects and elderly inpatients with no swallowing problems. The duration of laryngeal elevation (DOLE) for swallowing the carbonated beverage and water in the second session was shorter compared to that for water in the first session in the elderly subjects. The DOLE and the duration of suprahyoid muscle activity for swallowing were longer in the elderly subjects than in the young subjects for all beverages. Beverages that the subjects subjectively felt were easy to swallow were the sports drink and carbonated beverage, whereas they stated that carbonated water was less easy to swallow. In the elderly subjects, swallowing ability latently decreased, even though they had no problem swallowing in their daily lives, and it was assumed that the carbonated beverage improved pharyngeal swallowing. In addition, the carbonated beverage also influenced the subsequent swallowing of water, showing a persistent effect. It was suggested that carbonated beverages are easy to swallow and effective for improving pharyngeal swallowing.

Analysis of dynamic sitting balance on the independence of gait in hemiparetic patients.

The purpose of this study was to investigate the relationship between dynamic sitting balance and walking ability in stroke patients. Patients were evaluated using functional independence measure (FIM), and those with a locomotion score of 5 or below were categorized into the dependent walking and below group (dependent group) and those with a score of 6 or above were categorized into the independent walking group (independent group). They were asked to take a sitting position at the center of an unstable platform (seesaw). The experimenter passively tilted the unstable platform to the paretic side or non-paretic side by 10 degrees in the frontal plane. The unstable platform was released suddenly, with the experimenter supporting the platform with both hands, and the subjects were asked to control their posture so that their body axis came to the vertical position and the platform came to the horizontal position in the frontal plane. As a result, the body axis of left hemiplegic patients significantly tilted to the non-paretic side. On the other hand, in the dependent group in the right as well as left hemiplegic patients, the patients heads were tilted to the side from which tilting was started, though not significantly in both conditions. This study demonstrated that patients with poor walking function have a deviated verticality of the head and the body axis. We surmise that patients whose body axis tilts towards the non-paretic side during a dynamic balance maintenance task like this test would have lower walking independence.