Deterministic generation of a perfect soliton crystal microcomb with a saturable absorber.

We numerically investigate the deterministic generation of a perfect soliton crystal (PSC) in an optical microresonator functionalized with a saturable absorber (SA). The SA allows the direct formation of a PSC from an initial, periodic Turing roll. It prevents passage through a chaotic state, which induces a stochastic nature with regard to the number of generated dissipative Kerr solitons. We show that PSCs form deterministically, and the number is controlled by adjusting the input power and SA parameter. Our work provides a simple approach for obtaining a stable PSC that offers an ultrahigh repetition rate and a high comb output power.

Tongue muscle strength affects posterior pharyngeal wall advancement during swallowing: A cross-sectional study of outpatients with dysphagia.

BACKGROUND: Tongue muscle strength is important for swallowing but decreases with age, in association with reduced skeletal muscle mass. However, the relationships between pharyngeal dynamics and both skeletal muscle mass and tongue muscle strength are unknown. OBJECTIVE: To investigate the effect of reductions in tongue muscle strength on pharyngeal movement during swallowing in patients with dysphagia. METHODS: Subjects were selected from male outpatients ≥65 years old who were examined for the main complaint of dysphagia. Patients with history of neurodegenerative disease affecting tongue movement, cerebrovascular disease or oral cancer were excluded. As a result, 82 men (mean age, 80.6 ± 6.8 years) participated. Skeletal muscle mass index (SMI) as physical parameters and maximum tongue pressure (MTP) as tongue muscles strength were measured. Status and dynamics of the pharyngeal organs, including change in posterior pharyngeal wall advancement (PPWA) when swallowing 3.0 mL of moderately thick liquid, were measured by analysing videofluoroscopic images. Simple bivariate correlation and multiple regression analysis were used to statistically analyse correlations between parameters. RESULTS: MTP showed a significant positive correlation with SMI (r = .43, P < .01). PPWA showed a significant negative correlation with MTP (r = -0.30, P < .01), but no association with SMI. CONCLUSIONS: While tongue muscle strength is affected by skeletal muscle mass, posterior pharyngeal wall advancement is not readily affected by decreases in skeletal muscle mass. Posterior pharyngeal wall advancement may increase to compensate for swallowing function among individuals with reduced tongue muscle strength.

The effects of sarcopenic dysphagia on the dynamics of swallowing organs observed on videofluoroscopic swallowing studies.

OBJECTIVES: The aim of the present study was (a) to determine the relationship of videofluoroscopic swallowing study (VFSS) findings of the swallowing musculature with the diagnostic criteria for sarcopenic dysphagia and (b) to examine the usefulness of VFSS for diagnosing sarcopenic dysphagia. METHODS: The participants were 132 patients (mean age, 80.4 ± 8.8 years). Their skeletal muscle mass, nutritional status and swallowing functions as assessed by VFSS findings were measured. Also, the relationship between the VFSS findings and sarcopenia was examined. RESULTS: Of all the participants, 20 men (mean age, 83.2 ± 6.9 years) and 27 women (mean age, 85.3 ± 6.9 years) were diagnosed with sarcopenia. In men, the amount of laryngeal upward movement (ALUM) was significantly lower and the pharyngeal area was significantly wider in the sarcopenia group than in the non-sarcopenia group. In women, the pharyngeal area was significantly wider in the sarcopenia group than in the non-sarcopenia group. In a logistic regression model, ALUM (odds ratio [OR] 1.135, 95% confidence interval [CI] 1.037-1.241, P = .006) and pharyngeal area (OR 0.028, 95% CI 0.001-0.670, P = .027) was a significant independent factor for the presence or absence of sarcopenia. CONCLUSIONS: The decline in swallowing function of sarcopenia patients was characterised by lower laryngeal movement and enlargement of the pharyngeal cavity due to decreased skeletal muscle mass and decreased muscle strength. The present study suggested the usefulness of measuring ALUM during swallowing and measuring the pharyngeal area with VFSS as indicators of decreased swallowing muscle function in sarcopenia.

Development of the Sakiika transport test: A practical screening method for patients with oral-phase dysphagia.

PURPOSE: This study aimed to develop a simple screening test for mastication, "the Sakiika (squid jerky) transport test (STT), which evaluates the vertical jaw movement coordinated with the lateral tongue movement during stage I transport, and investigate the possibility of its clinical application. METHODS: The study included 73 people with dysphagia (mean age, 78.5 ± 7.8 years; median age, 79.0 years; interquartile range, 75.0-84.0). The STT evaluated the ability of a participant to transport a piece of squid jerky placed on the midline of the tongue to the molar region. The STT score was defined as the number of vertical jaw movements occurring as the tongue transported food to the molars. A cutoff value was set by comparing the STT scores with masticatory function evaluated via a videofluoroscopic swallowing study and with food texture evaluated using the Food Intake LEVEL Scale (FILS). RESULTS: The STT scores counted by the two examiners had a κ coefficient of 0.79, indicating good reliability. The STT score was significantly associated with both the presence of masticatory movement ( p = 0.019) and food texture classified by FILS ( p = 0.032) at cutoff value of "3" (3 vertical movements). The STT showed 62% sensitivity and 75% specificity for masticatory movements. CONCLUSION: The STT could be a useful screening test to assess the presence or absence of food transportation to the molars for mastication in older patients with dysphagia. In addition, the STT could be useful in identifying the need to modify food texture to meet functions.