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The paper reviews human mastication, focusing on its age-related changes. The first part describes mastication adaptation in young healthy individuals. Adaptation to obtain a food bolus ready to be swallowed relies on variations in number of cycles, muscle strength and volume of emitted saliva. As a result, the food bolus displays granulometric and rheological properties, the values of which are maintained within the adaptive range of deglutition. The second part concerns healthy ageing. Some mastication parameters are slightly modified by age, but ageing itself does not impair mastication, as the adaptation possibilities remain operant. The third part reports on very aged subjects, who display frequent systemic or local diseases. Local and/or general diseases such as tooth loss, salivary defect, or motor impairment are then indistinguishably superimposed on the effects of very old age. The resulting impaired function increases the risk of aspiration and choking. Lastly, the consequences for eating behaviour and nutrition are evoked. [ABSTRACT FROM AUTHOR]

Background: Swallowing is one of the most important activities in our life and serves the dual roles of nutritional intake and eating enjoyment. Objective: The study aimed to conduct a meta‐analysis to investigate the brain activity of swallowing. Methods: Studies of swallowing using functional magnetic resonance imaging were reviewed in PubMed, Web of Science, China National Knowledge Infrastructure (CNKI), Chinese Science and Technology Periodical Database (VIP) and Wan Fang before 30 November 2021. Two authors analysed the studies for eligibility criteria. The final inclusion of studies was decided by consensus. An activation likelihood estimation (ALE) meta‐analysis of these studies was performed with GingerALE, including 16 studies. Results: For swallowing, clusters with high activation likelihood were found in the bilateral insula, bilateral pre‐central gyrus, bilateral post‐central gyrus, left transverse temporal gyrus, right medial front gyrus, bilateral inferior frontal gyrus and bilateral cingulate gyrus. For water swallowing, clusters with high activation likelihood were found in the bilateral inferior frontal gyrus and the left pre‐central gyrus. For saliva swallowing, clusters with high activation likelihood were found in the bilateral cingulate gyrus, bilateral pre‐central gyrus, left post‐central gyrus and left transverse gyrus. Conclusion: This meta‐analysis reflects that swallowing is regulated by both sensory and motor cortex, and saliva swallowing activates more brain areas than water swallowing, which would promote our knowledge of swallowing and provide some direction for clinical and other research. [ABSTRACT FROM AUTHOR]

Background: Dysphagia is a common disorder following a cerebrovascular accident. It can cause detrimental effects on patient's quality of life and nutrition intake, especially in older adults. Neuromuscular electrical stimulation has been one of the management strategies for acceleration of the recovery. This review summarises the current evidence on sensory threshold stimulation of the procedure. Method: This review compiled data from the Internet database PubMed, Cochrane Library and Scopus using combination of MeSH thesaurus: 'Sensory threshold', 'electrical stimulation', 'neuromuscular stimulation', 'Deglutition', 'Dysphagia'. Eleven studies were intergraded into the review. Results: Most of the studies show significant improvement to the outcomes of sensory neuromuscular electrical stimulation treatment. In many cases, the results of the treatment are comparable or superior to motor threshold stimulation and conventional therapy. However, the study design and parameters of the procedure varied greatly without conclusive standardised guidelines. Conclusion: The sensory neuromuscular electrical stimulation (SNMES) is a viable treatment option for treating oropharyngeal dysphagia. The most suggested application parameters are an intensity at sensory threshold, a frequency of 80 Hz, an impulse time of 700 μs, a combined total duration of 20 h of stimulation in a 2‐week period, and placing the electrodes in the submental area of the neck. However, further research is necessary to construct a definitive guideline for clinicians. [ABSTRACT FROM AUTHOR]

Background: There have been no standard protocols of oral exercises for maintaining and improving oral function for people with dementia. Objective: This study aimed to determine the effects of home‐based oral exercises on the oral function of people with mild to moderate dementia. Methods: Twenty‐two participants at King Chulalongkorn Memorial Hospital were randomly assigned to the exercise group (n = 11) or control group (n = 11). The exercise group was instructed to do three home‐based oral exercises, consisting of tongue‐strengthening, oral diadochokinesis (ODK) and mouth‐opening exercises, for 3 months, while the control group received advice on oral health care. The maximum tongue pressure (MTP) was the primary outcome. MTP, ODK rates of /pa/, /ta/, /ka/, modified water swallowing test (MWST) and oral moisture were measured at baseline, and after 1, 2 and 3 months of training. The generalised estimating equation analysis was used to evaluate the effects of oral exercises on the oral function. Results: The MTP and all ODK rates in the exercise group were significantly increased after 3 months of training. There were significant interaction effects between time and intervention in MTP and all ODK rates. No significant interaction effects between time and intervention in oral moisture were found. The MWST scores in both groups did not change through the end of study, and no adverse effects were reported. Conclusion: Home‐based oral exercises were found to be effective for improving tongue strength and tongue‐lip motor function in people with mild to moderate dementia. [ABSTRACT FROM AUTHOR]

Background: Rehabilitative treatments for oropharyngeal dysphagia, including oromotor exercises and sensory stimulation, have been widely adopted into clinical practice. However, the effects of these treatments are mainly supported by exploratory studies. As such, their clinical efficacy remains uncertain. Objective: Our systematic review and meta‐analysis aimed to evaluate the efficacy of intraoral treatments for neurogenic oropharyngeal dysphagia based on evidence from randomised controlled trials (RCTs). Methods: Six electronic databases were systematically searched between January 1970 and July 2021. Data were extracted and analysed by two independent reviewers. The outcome measure was changes in (any) relevant clinical swallowing‐related characteristics. Results: Data from 285 dysphagic patients were collected from 8 RCT studies across a range of intraoral dysphagia treatments. The pooled effect size of all intraoral dysphagia treatments was non‐significant compared to control comparators (SMD [95%CI] = 0.23 [−0.22, 0.69], p =.31; I2 = 73%). Subgroup analysis revealed that the pooled effect sizes were also non‐significant for oromotor exercises (device‐facilitated lip resistance exercises and tongue exercises) (SMD [95%CI] = 0.11 [−0.76, 0.97]; p =.81; I2 = 88%) and sensory stimulation (thermal‐tactile, thermo‐chemical and electrical stimulation) (SMD [95%CI] = 0.35 [−0.03, 0.72]; p =.07; I2 = 0%). Conclusions: Our results showed that overall, intraoral dysphagia treatments, including oromotor exercises and sensory stimulation, do not show beneficial effects for neurogenic oropharyngeal dysphagia. The evidence for these treatments remains weak and currently inadequate to support clinical use. Large‐scale, multi‐centre RCTs are warranted to fully explore their clinical efficacy. [ABSTRACT FROM AUTHOR]

Oral dysfunction, including oral uncleanness and decline in tongue motor function, tongue pressure and swallowing function, precedes frailty. The tongue's dorsum is a reservoir of oral microbiota, desquamated epithelial mucosa and leukocytes due to the multi‐papillate anatomy, and leads to tongue coating. The tongue coating is frequently found in older adults because of hyposalivation, immunity's hypoactivity, diminished motor function and compromised tongue's pressure with age. Anaerobe‐driven volatile sulphur compounds in tongue coating are a major cause of intra‐oral malodor. Dysbiosis of the tongue‐coating microbiome rather than the amount of microorganisms is associated with a risk of aspiration pneumonia. Daily tongue cleaning with a brush or scraper is an easy way to control tongue coating deposits and quality. Using mouth wash or rinse‐containing germicides is also a way to control the microbiota of tongue coating. The tongue function is closely related to swallowing. Tongue and suprahyoid muscles are linked with respiratory muscles through the endothoracic fascia. The mechanical stimulation during the cleaning of the tongue may stimulate the respiratory muscles. An intervention trial revealed that tongue cleaning by mucosal brush improves tongue pressure, swallowing and respiratory function in old residents of nursing homes, suggesting a rehabilitative effect of tongue cleaning on the swallowing and respiratory functions, preventing aspiration pneumonia. This narrative review assesses the tongue‐cleaning benefits for respiratory and swallowing functions and the possibility of preventing aspiration pneumonia. [ABSTRACT FROM AUTHOR]

The individual inclination to lead an autonomous life until death is associated with requirements that may be of physiological, psychosocial and environmental nature. We aim to describe a conceptual oro‐facial health model with an emphasis on oro‐facial function, taking the domains of quality of life and patient‐centred values into account. In the context of oro‐facial function, the requirements of life are met when the oro‐facial system is in a fit state. 'Fitness of the oro‐facial system, that is oro‐facial health, is a state that is characterised by an absence of, or positive coping with physical disease, mental disease, pain and negative environmental and social factors. It will allow natural oro‐facial functions such as sensing, tasting, touching, biting, chewing, swallowing, speaking, yawning, kissing and facial expression'. In the presented conceptual model of oro‐facial health, it is postulated that each individual has present and future potentials related to biological prerequisites and resources that are developed by an individual through the course of life. These potentials form the oro‐facial functional capacity. When the individual potentials together do not meet the requirements of life anymore, dysfunction and disease result. The oro‐facial system is subject to physiological ageing processes, which will inevitably lead to a decrease in the oro‐facial functional capacity. Furthermore, comorbid medical conditions might hamper oro‐facial function and, alongside with the ageing process, may lead to a state of oral hypofunction. Currently, there is a lack of widespread, validated, easy‐to‐use instruments that help to distinguish between states of oro‐facial fitness as opposed to oral hypofunction. Clearly, research is needed to establish adequate, validated instruments alongside with functional rehabilitation procedures. [ABSTRACT FROM AUTHOR]

Background: Single implant mandibular overdentures (SIMOs) can improve mastication in edentulous elderly people. However, little attention has been paid to their effects on articulation disorders and the swallowing threshold relative to those of conventional complete dentures (CDs). Objective: To compare the effects of new conventional CD set and SIMOs on articulation disorders, mandibular movements during speech and swallowing threshold using a paired study design. Methods: Twenty‐two edentulous Brazilian Portuguese–speaking elderly people (mean age 66.7 ± 4.6 years) were first evaluated whilst wearing their old conventional CDs. Articulation disorders were analysed by audio and video recordings, mandibular movements during speech were measured by kinesiography, and the swallowing threshold was assessed by masticatory cycle counting and medium particle size (X50) calculation. Participants then received new conventional CDs, and evaluations were repeated 2 months later. Subsequently, single implants were installed in the midlines of subjects' mandibles, and the conventional CDs were converted to SIMOs. After 2 months of SIMOs use, the evaluations were repeated. Data were submitted to the Cochran‐Mantel‐Haenszel and ANOVA. Results: No difference in articulation disorders was found between new conventional CD and SIMO use. The frequency of anterior lisp during /s/ and /z/ phoneme pronunciation was reduced with new conventional CD use relative to old conventional CD use (p <.05). The X50 decreased progressively with new conventional CD and SIMO use (both p <.05). Conclusion: SIMOs do not alter speech relative to new well‐fitted conventional CDs, but improved the swallowing threshold, in edentulous elderly people. [ABSTRACT FROM AUTHOR]

A recently described method for studying occlusal forces in prosthetically restored dentitions (Lundgren & Laurell, 1984) was applied in a standardized programme to elucidate the occlusal force pattern and the functional capability of a dentition during chewing and biting. The method is based on the use of strain gauge transducers mounted into preformed matrices evenly distributed over the tooth-arch. The programme was tested in a subject prosthetically restored with a fixed bridge of crossarch design in the upper jaw, and with unsplinted teeth in the lower jaw. It involved chewing of(a) peanuts, (b) roast beef with potato salad, biting with maximal strength in habitual occlusion and biting over one limited contact area at a time. The magnitude of the occlusal forces developed during chewing and swallowing was well below all biting forces. The magnitude of the total force acting over the entire dentition when biting at maximal strength in habitual occlusion did not seem to be limited by reactions from the teeth or the periodontal tissues but, seemingly, by the capability of the jaw-closing muscles themselves. The magnitude of the local bite force over one limited contact area at a time was much smaller than that which the jaw-closing muscles were able to develop. This indicated that feedback mechanisms in the periodontal tissues and/or the temporo-mandibular joints were limiting factors for these forces. The programme will be applied to studies of dentitions supplied with prosthetic constructions of various design and with different distribution of periodontal support. [ABSTRACT FROM AUTHOR]

There is wide variation in chewing behaviours, even among healthy humans. Further, the way in which humans determine swallowing initiation when chewing solid foods remains unclear. The current study sought to investigate how the bolus properties change over time during chewing, and to clarify which factors affect chewing and swallowing behaviours, including swallowing initiation, in healthy humans. Twenty‐four healthy volunteers were instructed to chew 8 g of steamed rice and spit it out at 50%, 100% and 150% of their own chewing duration, defined as the time of chewing from onset of the first chewing cycle to onset of the first swallow. Chewing and swallowing behaviours were monitored and determined by visual inspection of video recordings. The physical properties such as hardness, cohesiveness and adhesiveness as well as water content of the bolus were measured. In each subject, maximum bite force, tongue pressure and stimulated salivary flow rate were also measured. Hardness gradually decreased, and the cohesiveness and water content of the bolus did not change up to 50% of chewing duration, followed by a slight but significant increase. The adhesiveness of the bolus rapidly decreased at the beginning of chewing. Chewing duration was significantly related to stimulated salivary flow rate; greater salivary flow rate was associated with shorter chewing duration. Variation of chewing duration and swallowing initiation was not dependent on bolus properties during the chewing of steamed rice, but mainly depended on the surface lubrication of the bolus. [ABSTRACT FROM AUTHOR]

Background: Dysphagia is a growing health problem in aging societies. An observational cohort study targeting community‐dwelling populations revealed that 16% of elderly subjects present with dysphagia. There is a need in elderly communities for systematic dysphagia assessment. Objective: This study aimed to verify whether laryngeal elevation in the pharyngeal phase could be measured from the body surface using thin and flexible stretch sensors. Methods: Thirty‐two elderly subjects (17 males, 15 females; mean age ± SD: 89.2 ± 6.2 years) with suspected dysphagia underwent a swallowing contrast examination in which seven stretch sensors were attached to the front of the neck. The elongation of the sensors was measured and compared to the laryngeal elevation time values obtained using videofluorography. The sensor signal detected the laryngeal elevation start time, conclusion of the descent of the larynx, and the laryngeal elevation time. The respective laryngeal elevation times obtained using videofluorography and using the sensor were compared using the Bland–Altman method. Results: The laryngeal elevation time was 1.34 ± 0.46 s with the stretch sensor and 1.49 ± 0.56 s with videofluorography. There was a significant positive correlation between the duration obtained by both methods (r =.69, P <.0001). A negative additional significant bias of −0.15 s (95% confidence interval −0.30 to −0.03, P =.046) was noted in the laryngeal elevation time from the videofluorography measurement. Conclusion: Laryngeal elevation time can be measured non‐invasively from the neck surface using stretch sensors. [ABSTRACT FROM AUTHOR]

Background: Quantitative assessment of swallowing function is necessary to prevent swallowing impairment due to ageing. Though surface electromyography (EMG) has been widely used to measure swallowing activity, the relationship between EMG results and swallowing function is unclear. Objective: This study examined the relationship between the temporal characteristics of muscle activity and laryngeal elevation (LE) during swallowing. Methods: This study analysed 60 healthy volunteers in two age groups (young, between 20 and 38 years; old, between 65 and 75 years), each containing the same number of male and female participants. Surface EMG signals were recorded from the suprahyoid and infrahyoid muscle groups (SH‐EMG and IH‐EMG, respectively). LE was measured using an array of pressure sensors. The participants swallowed 3 mL of water under three swallowing speed conditions: fast, normal and slow swallowing. The EMG duration, EMG time intervals before and after the onset of LE (pre‐LE and post‐LE intervals, respectively), and the LE velocity were analysed. Results: Both EMG duration and the post‐LE interval of IH‐EMG were significantly longer in the older group. As for the gender effect, the pre‐LE interval of SH‐EMG was significantly longer and the LE velocity was significantly higher in men than in women. Furthermore, there was a negative correlation between pre‐LE interval and LE velocity in the fast swallowing condition. Conclusion: Though ageing slightly prolonged the muscle activity time, gender influenced swallowing activity in a more complex manner. Therefore, it is important to take gender into account when examining swallowing function with increasing age. [ABSTRACT FROM AUTHOR]

Background: There is growing international interest in the prevention of decreased oral function for managing oral health in older people. Objective: The aims of the present study were to identify factors related to decreases in masticatory performance and masticatory function until swallowing in subjects aged 20‐79 years old. Methods: A total of 152 subjects, ranging in age from 20 to 79 years, were divided into six groups according to their chronological age: 20‐29, 30‐39, 40‐49, 50‐59, 60‐69 and 70‐79 years. Grip strength, maximum occlusal force, maximum tongue pressure, masticatory performance and swallowing threshold were measured in all subjects. Masticatory performance and swallowing threshold were determined according to the concentration of dissolved glucose obtained from gummy jellies; decreased masticatory performance and decreased swallowing threshold were defined as glucose concentrations in the lowest 20th percentile. A multivariate binary logistic regression analysis was used to identify factors associated with decreased masticatory performance and decreased swallowing threshold. A self‐administered lifestyle questionnaire was also completed. Results: Logistic regression analyses revealed that factors related to decreased masticatory performance included use of more than one kind of medicine for treating chronic diseases and removable denture use, while factors related to decreased swallowing threshold included eating between meals once or more per day, poorer mental health and decreased saliva flow. Conclusions: Different factors are related to decreased masticatory performance and decreased swallowing threshold, although both of these phenomena are closely associated with general health status. [ABSTRACT FROM AUTHOR]

Gustatory function is closely related to chewing and swallowing; however, there are currently no reports regarding gustatory function in persons with cerebral palsy (CP). The aim of this study was to compare the gustatory function between persons with CP and healthy controls. We investigated sweet, salty, sour and bitter tastes using the whole‐mouth method and measured the electrogustometric thresholds in the chorda tympani nerve area. Twelve participants with CP (6 women and 6 men) for whom gustatory testing was possible at our facilities, and 17 age‐matched controls (9 women and 8 men) were included. The mean age ± standard deviation was 58.6 ± 8.1 years and 58.5 ± 8.7 years in subjects with CP and controls, respectively. Taste detection and identification were significantly worse in persons with CP compared with the controls. Taste identification was more impaired than taste detection. At the highest concentration, taste identification was impossible 11 times out of 48 (12 persons × 4 kinds of tastes) in persons with CP but such a deficit was not observed in 68 attempts (17 persons × 4 kinds of tastes) involving controls. The electrogustometric thresholds were not significantly different between the groups. Gustatory function associated with chewing and swallowing is worse in persons with CP compared to the controls. [ABSTRACT FROM AUTHOR]

This review focuses on the capacity of the brain for plasticity and the utility and efficacy of oral implants in helping to restore oro‐facial sensorimotor functions, especially in elderly patients. The review first outlines the components of the oro‐facial sensorimotor system which encompasses both oro‐facial tissues and a number of brain regions. One such region is the sensorimotor cortex that controls the activity of the numerous oro‐facial skeletal muscles. These muscles are involved in a number of functions including reflexes and the more complex sensorimotor functions of mastication, swallowing and speech. The review outlines the use by the brain of sensory inputs from oro‐facial receptors in order to provide for exquisite sensorimotor control of the activity of the oro‐facial muscles. It highlights the role in this sensorimotor control played by periodontal mechanoreceptors and their sensory inputs to the brain, and how oral implants in concert with the plastic capacity of the brain may, at least in part, compensate for reduced sensorimotor functioning when teeth are lost. It outlines findings of ageing‐related decrements in oro‐facial sensorimotor functions and control. The changes in oro‐facial tissues and the brain that underlie these ageing‐related functional alterations are also considered, along with adaptive and compensatory processes that utilise the brain's capacity for plasticity. The review also notes the evidence that rehabilitation that incorporates adjunctive approaches such as sensorimotor training paradigms in addition to oral prostheses such as implants may enhance these processes and help maintain or facilitate recovery of sensorimotor functioning in the elderly. [ABSTRACT FROM AUTHOR]

Summary: Background: Lingual exercises are commonly used in clinical practice for swallowing rehabilitation. Associating lingual exercises with computer games increases motivation, which influences tongue motor performance. Objective: To investigate the effects of tongue movement direction; resistance force level; repetition number; sustained tongue contraction duration; age and gender on tongue motor performance in healthy adults using computer games. Methods: An observational pilot study was carried out at a university laboratory. Nine healthy adults, aged 22 to 38 years, used an intra‐oral joystick controlled by the tongue to play four computer games. The participants had to reach 12 targets that appeared on the computer screen using the intra‐oral joystick. Motor performance was measured by the number of attempts to score and the time during which the target force was maintained. Tongue motor performance was compared among tongue movement direction, resistance force level, game round number, and continuous force application time on the target, age and gender. Results: The number of attempts depended significantly on the direction, continuous force application time on the target and age. The time during which the target force was maintained depended significantly on the direction, continuous force application time on the target and game round number. There were no significant differences in the comparisons by gender or by resistance force level. Conclusions: It was seen that young adults had their best performance in the downward direction, on the third round, holding the force for a shorter time. The performance deteriorated as age increased. [ABSTRACT FROM AUTHOR]

Summary: Background: Several methods exist for objectively evaluating chewing efficiency by using gummy jelly. However, the validity of the subjective visual evaluation of chewing efficiency has not been assessed. Objective: To verify with an epidemiological study, the validity of a visual scoring method using gummy jelly by testing the relationship between masticatory performance (MP) using a fully automatic measuring system and visual score (VS) using a visual scoring method. Methods: Community‐dwelling elderly individuals (n = 1234) ≥70 years old participated. One evaluator measured VS consecutively after participants chewed the gummy jelly (ie, actual‐VS). The chewed jelly was photographed. Two evaluators used the photograph to measure the gummy jelly (ie, photo‐VS). To test the validity of both methods, the correlation between actual‐VS and MP and between photo‐VS and MP were analysed. Inter‐rater reliability between the evaluators of photo‐VS was analysed. Results: Significant correlations existed between actual‐VS and MP and between photo‐VS and MP (r = 0.86‐0.87; P < 0.001). The intra‐class correlation coefficient of the inter‐rater reliability for photo‐VS was very high (0.93; P < 0.001; 95% confidence interval: 0.877‐0.953); however, the distribution of photo‐VS deviated slightly from the actual‐VS. A large coefficient of variation in the MP for low VSs suggested the influence of incomplete comminution, which was not reflected by the VS, and the accidental swallowing of small pieces during chewing. Conclusion: The VS deviated slightly from the MP calculated using a fully automated method; however, the VS can be utilised for epidemiological surveys with numerous participants. [ABSTRACT FROM AUTHOR]

Summary: Background: Cognitive status is important for performing the assessment and treatment of dysphagia. Nonetheless, the cognitive neuropsychological profile of patients with stroke and dysphagia is not studied as deeply enough as it should be. On the one hand, focal and non‐focal brain lesions may lead to dysphagia and cognitive disorders, and on the other hand, the cognitive status possibly affects swallowing. In this study, cognition is supposed to be a mediator between brain lesion and swallowing disorder (dysphagia). The role of cognition and attention as mediators between brain lesion and dysphagia was evaluated via three causal models in which the causal mechanisms of swallowing were explained. Methods: Eighty‐eight patients with their first stroke (34 women and 54 men) in the acute phase (mean: 3.5 days after stroke; SD: 2.7) participated in this research. The data of dysphagic and non‐dysphagic patients were entered into structural equation models. Two relationships were estimated: a direct relationship between brain lesion and dysphagia and an indirect association between brain lesion and dysphagia through cognition and attention. Results: The goodness‐of‐fit indices confirmed the three models. Our first model proved a good fit [CFI = 1.00; TLI = 1.00]. The second model revealed an appropriate goodness of fit [CFI = 1.00; TLI = 1.00]. Our third model also showed a good fit [CFI = 1.00; TLI = 1.00]. Conclusion: It is suggested that in the assessment and treatment of dysphagia, cognition is better to be considered as a mediator along with physical aspects of dysphagia. [ABSTRACT FROM AUTHOR]

The relationship between type 2 diabetes oral physiology, nutritional intake and quality of life has not been fully elucidated. We assessed the impact of type 2 diabetes - exclusive or associated with hypertension with beta-blockers treatment - on oral physiology, mastication, nutrition and quality of life. This cross-sectional study was performed with 78 complete dentate subjects (15 natural teeth and six masticatory units minimum; without removable or fixed prostheses), divided into three groups: diabetics ( DM) ( n = 20; 45·4 ± 9·5 years), diabetics with hypertension and receiving beta-blockers treatment ( DMH) ( n = 19; 41·1 ± 5·1 years) and controls ( n = 39; 44·5 ± 11·7 years) matched for gender, age and socioeconomic status. Blood glucose, masticatory performance, swallowing threshold, taste, food intake, stimulated and unstimulated salivary flow, pH and buffering capacity of saliva were assessed. Glycemia was higher in DM than in controls ( P < 0·01). No differences were observed between DM and controls for nutrition and quality of life. Both stimulated and unstimulated salivary flow rate were lower in DMH ( P < 0·01), which also presented the lowest number of teeth and masticatory units ( P < 0·0001), and reduction in the number of chewing cycles ( P < 0·01). Controls showed lower Decayed Missing Filled Teeth index ( DMFT) scores in comparison with DMH ( P = 0·021). Masticatory performance and saliva buffering capacity were similar among groups. Exclusive type 2 diabetes did not alter oral physiology, nutrition or quality of life. However, when hypertension and beta-blockers treatment were associated with diabetes, the salivary flow rate, chewing cycles and number of teeth decreased. [ABSTRACT FROM AUTHOR]

This research was designed to investigate the acoustic characteristics of voluntary expiratory sounds after swallow for detecting dysphagia. Forty-nine patients with complaints of swallow difficulty received a videofluorographic ( VF) examination. They were divided into three groups: nine who did not have any apparent disease ( Group N), 22 patients with head and neck cancer ( Group H&N) and 18 patients with other diseases including cerebrovascular disease ( Group OD). After liquid barium swallows, they exhaled voluntarily without voicing. Videofluorographic findings were classified into four groups: normal ( Normal), acceptable swallow (Acceptable), swallow with residue (Resid) and swallows with penetration or aspiration (Pen/Asp). The duration of expiratory sounds was measured on the time waveform. Frequency characteristics of expiratory sounds were obtained using one-third octave band analysis ranging from 62·5 to 2000·0 Hz of central frequency. The averaged level of the 1000·0-Hz band was chosen as the reference band level ( RB level). The revised averaged level of each band was obtained by subtracting the RB level from the averaged level of each band. Zero decibel of the revised magnitude of the 125·0-Hz band was set as the critical value to differentiate dysphagia ( Resid or Pen/Asp) from no dysphagia ( Normal or Acceptable). Comparison of this assessment with VF findings showed a significant percentage agreement (85·4%). These results suggest that frequency characteristics of post-swallow expiratory sounds can differentiate dysphagia from no dysphagia among multiple dysphagic patient groups. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the muscle activity of the suprahyoid and infrahyoid muscles according to the number of Shaker exercise. The 19 experimental subjects were recruited and randomly assigned to the two experimental groups. The 1st experimental group performed Shaker exercise once a day, and 2nd experimental group performed Shaker exercise three times a day for 6 weeks. Shaker exercise consists of isometric and isotonic contraction movement, enhancing the strength of suprahyoid muscle and increasing the opening of UES. After performing Shaker exercise for 6 weeks, the muscle activity of experimental groups was measured and analysed by surface electromyography. As a result, muscle activity of the suprahyoid and infrahyoid muscles showed significant improvement in both groups ( P < 0·05). Comparing muscle activity of both groups, there was no significant difference. This means the Shaker exercise shows similar exercise effects on suprahyoid muscle which is the primary target muscle irrespective of the number of Shaker exercise. The activity of the infrahyoid muscle, which takes a supportive role, also showed significant difference between the two groups. In the results of a follow-up test after 4 weeks, muscle activity was higher than the initial status and the value of the EMG activity was statistically significant ( P < 0·05). These results by EMG study may suggest that Shaker exercise performed once a day, like performing three times a day, has enough exercise effect and there is similar effect on the suprahyoid muscle between the 2 groups. In addition, the exercise effect lasts for 4 weeks after completing exercise. [ABSTRACT FROM AUTHOR]

We tested the effects of cranio-cervical flexion ( CCF) on activation of swallowing-related muscles while swallowing liquid in a sample of 45 healthy volunteers. Activation following CCF movement was examined across two positions (supine and sitting) and, three pressure levels and two different postures were examined in each condition, respectively. When CCF was applied, activation of swallowing-related muscles was significantly increased compared to the neutral neck position, and such findings were found across both the supine and sitting positions. Also in the supine position, when the pressure level of the stabilizer was escalated, there was a significant difference in the activity of the swallowing-related muscles compared to the baseline level. In conclusion, our results suggest that CCF may be a viable method to enhance the effectiveness of swallowing-related muscles by changing neck position. When CCF is applied, the stability of the deep flexor muscles must be secured first after which superficially located muscles may better assist swallowing with less effort. [ABSTRACT FROM AUTHOR]

Activity patterns of the swallowing-related muscles were examined in normal subjects at different four body positions during swallowing of foods with different textural properties. Surface electromyograms were recorded from two muscle groups, the anterior tongue and suprahyoid muscles. The TP technique we developed was applied to the electromyograms for quantitative analysis of the activity patterns. Three test foods were prepared by dissolving 2·0% (low), 5·7% (middle) and 9·1% (high concentration) of a thickening agent into distilled water. Each subject was delivered randomly, one of the test foods to swallow at one of the four body positions i.e. horizontal supine, 30° inclined, 60° inclined and upright. In this study, T50 values were calculated in activity data of the two muscle groups, and the T50 values were statistically examined analysis of variance with a linear model including four fixed effects of ‘concentrations’, ‘body positions’, ‘subjects’ and ‘sessions’. Three major findings obtained were that (i) the activity pattern of the anterior tongue was altered from a decrementing discharge pattern to an incrementing discharge pattern by shifting from the upright to the horizontal supine position, (ii) the activity pattern of the suprahyoid muscles was altered from a decrementing discharge pattern to an incrementing discharge pattern by shifting from the low concentration food to the higher ones and (iii) two subgroups were detected in subjects with the significant effects of ‘concentrations’ and ‘body positions’. These findings lead a conclusion that activity patterns of the swallowing-related muscles are affected by food properties and body positions. [ABSTRACT FROM AUTHOR]

This study was carried out to clarify the distribution and individual variation of the number of chewing strokes before last swallowing (NCS), as well as to assess the factors that affect NCS, when dentulous adults masticate the same type of food. NCS was measured in 75 dentulous adults using gummy candies. Measurements were repeated five times to obtain the average and variation. Moreover, the correlation of NCS with various physiological factors (lateral width and vertical distance of chewing loop, angle of opening and closing path, opening and closing time, occlusal time, masticatory performance, number of occlusal contact points, occlusal contact area, occlusal force, flow rate of whole saliva and viscosity of whole saliva) and 28 personality factors were analysed by both of the single variate analysis and the multivariate analysis. The results showed that the average NCS was 41·0 ± 16·0, and the coefficient of variation was 0·090 ± 0·040. Additionally, the correlation between NCS and each factor was investigated, and found that any of these factors did not function as a single determinant for NCS. Following, determinant factors were further examined by the stepwise method of linear multiple regression analysis. From these analysis we found that when opening and closing time and four personality factors were combined, they were significantly involved in determining NCS ( P < 0·01). Therefore, we conclude that individual NCS until last swallowing is not determined by a sole, specific physiological factor but is affected by multiple factors including personality. [ABSTRACT FROM AUTHOR]

The activity of the anterior and posterior portions of the temporal muscle and in the upper and lower lips were studied electromyographically in 50 girls, aged 9-13 years with normal occlusion. The recordings were made during swallowing of water, saliva, apple and peanuts as well as during chewing of apple and peanuts. The maximal mean voltage amplitudes during swallowing varied notably with the test medium and were larger for solid than for fluid media. The amplitudes were the same for both portions of the temporal muscle, but always greater for the lower lip than for the upper. Many girls swallowed fluid media without demonstrable activity of the anterior portion of the temporal muscle, while absence of demonstrable activity in the lips was rare. No correlation was found between the degree of activity of the lips during swallowing of fluid and solid substances. The amplitudes during chewing were the same for both portions of the temporal muscle, but larger for the lower lip than for the upper. The amplitudes found for the two portions of the temporal muscle and for the upper and lower lips were intercorrelated both during swallowing and chewing. No correlation was found between the amplitudes from the lower lip and from the temporal muscle during swallowing. The amplitude from the upper lip during swallowing was correlated only with that from the posterior portion of the temporal muscle. Palpation of muscular activity of the temporal muscle during swallowing is of little or no value for estimating the degree of activity of the lip during swallowing. [ABSTRACT FROM AUTHOR]