Kimiko Abe

Effects of reclining posture on velopharyngeal closing pressure during swallowing and phonation

Velopharyngeal closure plays an important role in preventing air pressure leakage during swallowing and phonation from oropharynx to nasopharynx. Levator veli palatini muscle activity is influenced by oral and nasal air pressure, volume of the swallow bolus and postural changes. However, it is unclear how velopharyngeal closing pressure is affected by reclining posture. The purpose of this study was to investigate the effects of reclining posture on velopharyngeal closing pressure during swallowing and phonation. Nine healthy male volunteers (age range, 27-34 years) participated in this study. Velopharyngeal closing pressure during a dry swallow, a 5-mL liquid swallow, a 5-mL honey-thick liquid swallow and phonations of /P∧/ and /K∧/ were evaluated in an upright posture and at reclining postures of 60° and 30°. A manometer catheter was inserted transnasally onto the soft palate, and each trial was repeated three times. A solid-state manometer catheter with an intra-luminal transducer was used to evaluate the amplitude and duration of each trial, and data were statistically analysed. Average amplitudes during dry and liquid swallows were significantly lower in reclining postures compared with the upright posture, but the amplitude was not significantly different during the thick liquid swallow. Average durations were not affected by postural changes. The amplitudes during phonations were lower in reclining postures, but the differences were not significant. Velopharyngeal closure is significantly affected by reclining posture. This suggests that velopharyngeal closing pressure may be adjusted according to afferent inputs, such as reclining posture and bolus viscosity.

Changes in expression of growth-associated protein-43 in trigeminal ganglion neurons and of the jaw opening reflex following inferior alveolar nerve transection in rats

The aim of the present study was to clarify an involvement of growth-associated protein-43 (GAP-43) in the regeneration of primary afferent trigeminal ganglion (TG) neurons following inferior alveolar nerve transection (IANX). A larger number of GAP-43 immunoreactive (GAP-43 IR) TG neurons was observed in rats 3 d after IANX compared with sham rats. Growth-associated protein-43 IR TG neurons were also detected for 30 d after IANX, and the number of GAP-43 IR TG neurons was significantly higher in the IANX model until day 30. The relative number of large (>600 μm2) GAP-43 IR TG neurons was significantly lower, whereas the relative number of small (<400 μm2) GAP-43 IR TG neurons was significantly higher than that at day 0 until 30 d after IANX. To evaluate the functional recovery of damaged IAN, the jaw opening reflex (JOR), elicited by the electrical stimulation of the IAN, was measured before and after IANX. Jaw opening reflex occurrence was gradually increased and the relative threshold of electrical stimulation eliciting JOR was gradually decreased over the 30-d duration of the study. On day 30 after IANX, the JOR occurrence and relative JOR threshold were similar to those in sham rats. The present findings suggest that changes in the expression of GAP-43 in TG neurons after IANX are involved in regeneration and functional recovery of the transected IAN.

Video-endoscopic comparison of swallowing waxy rice mochi and waxy wheat mochi: improvement of a traditional Japanese food that presents a choking hazard

Mochi is highly cohesive and adhesive, and easy to choke on. Many of the fatal suffocation accidents with mochi occur in the elderly aged 65 years or older. These circumstances prompted us to investigate a special property of waxy wheat which is similar in texture to waxy rice, but is less cohesive and adhesive. We compared the differences in chewing and swallowing movements associated with eating waxy rice mochi and waxy wheat mochi between healthy adults and healthy elderly. Healthy elderly chewed mochi more and longer than healthy adults. Although there was no difference in the number of chewing cycles or total duration of chewing between the two types of mochi, waxy wheat mochi was easier to chew and left less pharyngeal residue. These findings lead us to suggest that waxy wheat mochi is promising as a food that is easy to swallow and difficult to choke on. Graphical Abstract This is the image which observed a chewing state of the Waxy wheat mochi by video-endoscopy. A green coloring agent was added to one set of samples to yield green and white mochi, allowing easy identification by video-endoscopy. Each bolus of waxy wheat and waxy rice mochi consisted of both white and green mochi.

The effects of ADL on recovery of swallowing function in stroke patients after acute phase.

This study aimed to examine the association between the degree of recovery from dysphagia and changes in functional independence measure (FIM) items in stroke patients after acute phase by conducting a historical cohort study, because none explains the effects of activities of daily living (ADL) on recovery of swallowing function. Study patients included hospitalised stroke patients after acute phase in whom dysphagia was confirmed (n = 72). Change in nutritional intake method score was examined for association with age, days from stroke onset to admission, length of hospital stay and change in FIM score. Moreover, to examine characteristics of patients who were removed from tube feeding, all patients who required tube feeding at the time of admission were divided into two groups comprising those who required tube feeding at discharge and those who did not. A significant and positive association was observed between change in nutritional intake method and FIM for all items other than self-care of bathing, locomotion of stairs and problem solving. Patients who were removed from tube feeding were significantly younger than those who required tube feeding at the time of discharge (P < 0.041) and also showed significantly higher FIM scores for transfer and all cognitive FIM items at the time of admission (P < 0.05). This study demonstrated that nutritional intake methods improve in conjunction with FIM improvements in patients with dysphagia following the acute phase of stroke. Our results suggest that the age and cognitive function may influence the recovery of patient ability of oral intake.

Facial Vibrotactile Stimulation Activates the Parasympathetic Nervous System: Study of Salivary Secretion, Heart Rate, Pupillary Reflex, and Functional Near-Infrared Spectroscopy Activity

We previously found that the greatest salivation response in healthy human subjects is produced by facial vibrotactile stimulation of 89 Hz frequency with 1.9 μm amplitude (89 Hz-S), as reported by Hiraba et al. (2012, 20011, and 2008). We assessed relationships between the blood flow to brain via functional near-infrared spectroscopy (fNIRS) in the frontal cortex and autonomic parameters. We used the heart rate (HRV: heart rate variability analysis in RR intervals), pupil reflex, and salivation as parameters, but the interrelation between each parameter and fNIRS measures remains unknown. We were to investigate the relationship in response to established paradigms using simultaneously each parameter-fNIRS recording in healthy human subjects. Analysis of fNIRS was examined by a comparison of various values between before and after various stimuli (89 Hz-S, 114 Hz-S, listen to classic music, and “Ahh” vocalization). We confirmed that vibrotactile stimulation (89 Hz) of the parotid glands led to the greatest salivation, greatest increase in heart rate variability, and the most constricted pupils. Furthermore, there were almost no detectable differences between fNIRS during 89 Hz-S and fNIRS during listening to classical music of fans. Thus, vibrotactile stimulation of 89 Hz seems to evoke parasympathetic activity.

Subjective oropharyngeal symptoms for abnormal swallowing in Japanese patients with obstructive sleep apnea syndrome: a descriptive questionnaire study.

Objectives: This study aimed to investigate the prevalence of clinical symptoms related to abnormal swallowing in a large sample of obstructive sleep apnea syndrome (OSAS) patients. Methods:Oropharyngeal symptoms for abnormal swallowing were assessed by a self-administered questionnaire in 507 consecutive patients (females: 65, males: 442; mean age: 49.6 ± 12.6 years old) with clinical symptoms of OSAS, enrolled for cardiorespiratory evaluation. Results:Overall, 16.2% of patients (82/507) had at least one symptom for abnormal swallowing and 6.3% (32/507) had two or more symptoms. The most frequent symptom was difficulty with coughing up phlegm during or after a meal (8.3%). Demographic, sleep, and clinical variables did not differ between the patients with and without abnormal symptoms. Conclusions:The results of the current study showed that 16% of middle-aged OSAS patients reported pharyngeal symptoms related to abnormal swallowing, regardless of the severity of OSAS.