Oropharyngeal swallowing and aging: a review

Videofluoroscopic analysis of the laryngeal movement of older adults in swallowing

Even without diseases that cause dysphagia, physiological swallowing function declines with age, increasing the risk of aspiration. This study analyzed age-related changes in laryngeal movement in older adults. The study population consisted of 10 volunteers in their 80s and six in their 20s. A videofluoroscopic study of 3 and 10 mL barium swallows was performed laterally using a digital fluorographic. The recorded images were retrieved to a personal computer and analyzed frame-by-frame using video analysis software. The movement of the larynx during swallowing, barium's pharyngeal transit time (PTT), and laryngeal elevation delay time (LEDT) were analyzed. Results were compared between the 20s and 80s age groups using statistical analyses. The PTT was shorter in the 20s than in the 80s age group. The PTT was significantly longer in the 80s group than in the 20s for both 3 and 10 mL barium swallows. LEDT in the 80s was statistically significantly longer than that in the 20s for the 10 ml barium. No statistically significant differences were found; however, there was a tendency for the 80s group to have more types of laryngeal movement velocity peaks. In this study, LEDT was prolonged in the 80s with 10 ml barium swallowing than in the 20s. Two peak patterns of laryngeal elevation during swallowing were observed. The velocity peaks showed a two-peak pattern when the patients were in their 80s and when the barium volume was tested at 10 mL. Our results suggest that aging's effect on swallowing relates to laryngeal elevation.

Impact of the perioperative assessment of deglutition on postoperative respiratory complications in elderly patients undergoing gastrectomy for gastric cancer

PURPOSE

To investigate the association between perioperative deglutition screening and postoperative respiratory complications (PRCs) in elderly patients undergoing gastrectomy for gastric cancer.

METHODS

We analyzed data from 86 patients with gastric cancer (aged ≥ 70 years) who underwent gastrectomy between October, 2016 and November, 2018. Videofluoroscopic swallowing examinations (VFSEs) were performed before and after surgery. We examined the association of these results with postoperative respiratory complications, as well as the relationships between demographic, operative, and swallowing function assessment data.

RESULTS

PRCs were identified in 16 patients. The results of pre- and postoperative VFSE showed abnormalities in 28 and 32 patients, respectively. Multivariate analysis revealed that abnormalities in the postoperative VFSEs were strongly associated with the development of PRCs (P = 0.002). The findings of this analysis suggests that ventilatory impairment, a Charlson comorbidity index score ≥ 3, and an open surgical approach are independent risk factors for PRCs.

CONCLUSION

This is the first study to demonstrate the efficacy of perioperative assessment of swallowing function using VFSE for predicting PRCs in elderly patients undergoing gastrectomy for gastric cancer.

Histological observations of age-related changes in the epiglottis associated with decreased deglutition function in older adults

Although the epiglottis plays a vital role in deglutition, histological studies of the epiglottis and surrounding ligaments associated with swallowing dysfunction are limited. Therefore, we performed histological observations to clarify age-related changes in the morphological characteristics of the epiglottis and surrounding structures. Tissue samples comprising the epiglottis and surrounding structures were collected from corpses that were both orally fed and tube-fed during their lifetimes. Following hematoxylin and eosin, Elastica Van Gieson, and immunohistochemical staining procedures, the chondrocytes, connective tissue, and glandular tissue were observed under the epiglottis epithelium, and intervening adipose tissue was observed in the surrounding area. Fatty degeneration of acinar cells was also observed in the glandular tissue, possibly because of aging. Bundles of elastic fibers were present around the vascular wall in the peri-epiglottic ligament, but some were reduced. Furthermore, large amounts of collagen fibers ran toward and through the cartilage, whereas the mesh-like elastic fibers stopped in front of the cartilage. Microfibrils considered to be oxytalan fibers, which are thinner and shorter than elastic fibers, were observed around the vascular wall and in the fiber bundles. Age-related changes included connective tissue fibrosis shown by the large amount of collagen fibers, atrophy of salivary glands, and an accompanying increase in adipose tissue. Regarding stretchability and elasticity, the elastic fibers may have an auxiliary function for laryngeal elevation during deglutition. This suggests that disuse atrophy of the laryngeal organs with or without oral intake might reduce the amount of elastic fiber in older adults.

Olfactory Stimulation Successfully Improves Swallowing Function of Aged Rats through Activating Central Neuronal Networks and Downstream DHPR-RyR-mediated Neuromuscular Activities

Presbyphagia is age-related changes in swallowing function, which imposes a high risk of aspiration in older adults. Considering olfactory stimulation (OS) can influence behavioral activities by modulating neuronal excitability, the present study aims to determine whether OS could improve the swallowing function of aged rats through activating the central neuronal networks and downstream muscular activities participated in the control of swallowing. Aged male Wistar rats received OS by inhaling a mixture of plant-based volatile molecules twice a day for 12 days were subjected to functional magnetic resonance imaging (fMRI) and c-fos, choline acetyltransferase (ChAT) immunostaining to detect the neuronal activities of the orbitofrontal cortex (OFC) and medullary nuclei engaged in swallowing control, respectively. The functional effects of OS on downstream pharyngeal muscle activity were examined by evaluating the dihydropyridine receptor-ryanodine receptor (DHPR-RyR) mediated intra-muscular Ca2 + expression, and analyzing the amplitude/frequency of muscle contraction, respectively. In untreated rats, only moderate signal of fMRI and mild c-fos/ChAT expression was detected in the OFC and medullary nuclei, respectively. However, following OS, intense signals of fMRI and immunostaining were clearly expressed in the orbitofronto-medullary networks. Functional data corresponded well with above findings in which OS significantly enhanced DHPR-RyR-mediated intra-muscular Ca2 + expression, effectively facilitated a larger amplitude of pharyngeal muscle contraction, and exhibited better performance in consuming larger amounts of daily dietary. As OS successfully activates the neuromuscular activities participated in the control of swallowing, applying OS may serve as an effective, easy, and safe strategy to greatly improve the swallow function of aging populations.

Effects of age and gender on swallowing activity assessed by electromyography and laryngeal elevation

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.

A Systematic Review of Physiological Changes in Swallowing in the Oldest Old

Age-related swallowing changes are well-researched in deglutology, usually distinguishing those over 60 years as older aged. World-wide, older adults are healthier and forecast to live longer: many over 85 years. It is necessary for clinicians to understand healthy swallowing changes in this 'oldest old' in order to appropriately manage swallowing complaints in older patients. This systematic review collated and critically appraised studies investigating swallowing changes in adults over 85 years using instrumental assessment. Criteria for inclusion were healthy subjects over 85 years. Exclusion criteria included studies focused on anatomy and oral processing. Studies published until December 2018 were retrieved from BIOSIS, CINAHL, Embase, Medline, and Scopus, totaling 2125 articles. During data screening, 64% of studies investigating age-related swallowing changes were excluded, as the oldest old were not recruited. After PRISMA screening, 44 articles met criteria. These were further reviewed for data extraction, bias and quality. Main quantitative age-related changes in swallowing included increases in delay in swallow onset, bolus transit times, duration of UES opening, pressure above the UES and UES relaxation pressure, and reduction in pressure at the UES. Few studies detected increased residue or airway compromise in the form of aspiration. Results were not easily comparable due to differences in age ranges, methods for deeming participants 'healthy', measures used to define swallowing physiology, and swallowing tasks. Age-related swallowing changes are identified that do not compromise safety. The oldest old are underrepresented in normative deglutition research. It is essential future studies plan accordingly to recruit those over 85 years.

The Mealtime Assessment Scale (MAS): Part 2 - Preliminary Psychometric Analysis

AIMS

The Mealtime Assessment Scale (MAS) was developed to assess swallowing safety and efficacy during the meal. The study aims to perform a preliminary validation of MAS by investigating internal consistency, inter-rater agreement, concurrent and known-group validity, and responsiveness.

METHODS

MAS was tested on 100 persons without dysphagia (group 1) and 100 persons with dysphagia (group 2). Fifty subjects were simultaneously evaluated at mealtime using MAS by two independent clinicians to test inter-rater agreement. For concurrent validity, MAS was correlated with the Mann Assessment of Swallowing Ability (MASA) and American Speech-Language-Hearing Association National Outcomes Measurement System (ASHA NOMS) swallowing scale. MAS scores of groups 1 and 2 were compared for known-group validity. Responsiveness was tested reassessing 36 patients from group 2 after diet improvement.

RESULTS

Internal consistency and responsiveness were established for efficacy but not for safety. For inter-rater agreement, an average deviation index <0.66 was found for all items. MAS showed strong correlations with MASA and ASHA NOMS. MAS scores were significantly different between groups 1 and 2.

CONCLUSION

Preliminary evidence of the validity and reliability of MAS was established, except for the internal consistency and the responsiveness of the safety subscale. Further studies need to complete the validation process.

Swallowing outcomes in patients with subcortical stroke associated with lesions of the caudate nucleus and insula

Objective The present study was performed to investigate the relationships between swallowing outcomes and lesion location, bolus characteristics, and age in patients with subcortical stroke.

PATIENTS

Patients with subcortical and insular stroke (mean age, 57.38 ± 12.71 years) were investigated. All patients (n = 21) completed both brain magnetic resonance imaging studies and videofluoroscopic swallowing studies. Main Outcome Measures The oral transit duration, pharyngeal transit duration (PTD), laryngeal response duration, and Penetration-Aspiration Scale (PAS) score were applied to examine the efficiency of propulsion and airway protection in three swallowing tasks. Path analyses were performed to assess the relationships between swallowing outcomes and lesion location, age, bolus viscosity, and bolus volume. Results Caudate nucleus (CN) lesions were associated with higher PAS scores. Insular lesions were associated with a longer PTD. Advanced age was associated with a longer PTD. Bolus viscosity significantly moderated the association between CN lesions and higher PAS scores. Conclusions In the present cohort, CN lesions impacted airway protection and insular lesions impacted pharyngeal transit. An increased bolus viscosity reduced the aspiration severity. These results suggest that lesion location is an important indicator to predict subsequent dysphagia in patients with subcortical stroke.

The gut in the beaker: Missing the surfactants?

Gastrointestinal drug administration is the preferred route for the majority of drugs however, the natural physiology and physicochemistry of the gastrointestinal tract is critical to absorption but complex and influenced by factors such as diet or disease. The pharmaceutical sciences drive for product consistency has led to the development of in vitro product performance tests whose utility and interpretation is hindered by the complexity, variability and a lack of understanding. This article explores some of these issues with respect to the drug, formulation and the presence of surfactant excipients and how these interact with the natural bile salt surfactants. Interactions start in the mouth and during swallowing but the stomach and small intestine present the major challenges related to drug dissolution, solubility, the impact of surfactants and supersaturation along with precipitation. The behaviour of lipid based formulations and the influence of surfactant excipients is explored along with the difficulties of translating in vitro results to in vivo performance. Possible future research areas are highlighted with the conclusion that, "a great deal of work using modern methods is still required to clarify the situation".

Laryngeal Elevation Velocity and Aspiration in Acute Ischemic Stroke Patients

Objectives

Aspiration after stroke has been associated with aspiration pneumonia, which contributes to increased mortality of stroke. Laryngeal elevation is a core mechanism for protection from aspiration. Few studies have explored the predictive value of laryngeal elevation velocity for aspiration after stroke. This study aimed to explore the ability of laryngeal elevation velocity to predict aspiration in patients with acute ischemic stroke.

Methods

This was a prospective cohort study that included consecutive acute ischemic stroke patients treated at a teaching hospital during a 10-month period. Patients underwent magnetic resonance imaging (MRI) to confirm the diagnosis of acute ischemic stroke. Patients who were at risk of aspiration and could swallow 5 ml of diluted barium (40%, w/v) for a videofluoroscopic swallowing (VFS) study were included. The association between abnormal indices in the oral and pharyngeal phase of the VFS study and aspiration was examined using univariate analyses. These indices included the lip closure, tongue movement and control, laryngeal elevation velocity and range, the latency of pharyngeal swallowing, pharyngeal transit time (PTT), abnormal epiglottis tilt, residual barium in the pharynx, and the duration of upper esophageal sphincter (UES) opening. The laryngeal elevation velocity (%/s) was calculated as the range of laryngeal elevation (%) from the resting position to the maximum superior position or to the position where the laryngeal vestibule is fully closed divided by the corresponding duration of laryngeal elevation. The range of laryngeal elevation (%) was the percentage calculated as the distance between the resting laryngeal position and the maximum superior excursion position or position where the laryngeal vestibule is fully closed divided by the distance between the resting laryngeal position and the lowest edge of the mandible. A logistic regression analysis was used to determine the predictive value for aspiration secondary to reduced laryngeal elevation velocity after adjusting for the effects of other indices. Intrarater and interrater reliability were calculated using Pearson’s correlation coefficients.

Results

Data from 89 patients were analyzed. This cohort included 71 males and 18 females with a mean age of 59.31±11.46 years. The mean time from stroke onset to the VFS study was 3 days (1–7). Twenty one (23%) patients aspirated while swallowing 5 ml of diluted barium (40%, w/v). Aspiration was associated with age, the velocity (%/s) of laryngeal elevation and duration, delayed pharyngeal phase, pharyngeal transit time, abnormal epiglottic tilt, and invalid laryngeal elevation before true swallowing, and duration of upper esophageal sphincter (UES) opening. After adjusting for the effects of the indices mentioned above, logistic regression analysis revealed that a reduced of laryngeal elevation velocity before vestibule closure was predictive of aspiration independently (OR, 0.993; 95% CI, 0.987–1.000).

Discussions

Reduced laryngeal elevation velocity for laryngeal elevated to position where laryngeal vestibule is fully closed was an independent predictor of aspiration in patients with acute ischemic stroke. This may be related to a decreased contraction velocity of the muscles involved in hyolaryngeal elevation. Therapeutic methods aimed at improving laryngeal elevation velocity may decrease aspiration events and pneumonias after stroke.

A preliminary evaluation of myoelectrical energy distribution of the front neck muscles in pharyngeal phase during normal swallowing

Pharyngeal phase is a central hub of swallowing in which food bolus pass through from the oral cavity to the esophageal. Proper understanding of the muscular activities in the pharyngeal phase is useful for assessing swallowing function and the occurrence of dysphagia in humans. In this study, high-density (HD) surface electromyography (sEMG) was used to study the muscular activities in the pharyngeal phase during swallowing tasks involving three healthy male subjects. The root mean square (RMS) of the HD sEMG data was computed by using a series of segmented windows as myoelectrical energy. And the RMS of each window covering all channels (16×5) formed a matrix. During the pharyngeal phase of swallowing, three of the matrixes were chosen and normalized to obtain the HD energy maps and the statistical parameter. The maps across different viscosity levels offered the energy distribution which showed the muscular activities of the left and right sides of the front neck muscles. In addition, the normalized average RMS (NARE) across different viscosity levels revealed a left-right significant correlation (r=0.868±0.629, p<;0.01) quantitatively, while it showed even stronger correlation when swallowing water. This pilot study suggests that HD sEMG would be a potential tool to evaluate muscular activities in pharyngeal phase during normal swallowing. Also, it might provide useful information for dysphagia diagnosis.

Age and gender effects on submental motor-evoked potentials

It is not known whether there are age- and/or gender-related differences in magnitude of motor-evoked potentials (MEPs) of the submental muscles. Knowledge of this is important in investigations of neurophysiological aspects of swallowing. Forty healthy participants (20 males, 20 females; 20 young [21-35 years], 20 old [53-88 years]) were recruited. Surface electromyography (EMG) electrodes were placed at midline underlying the submental muscle group. Age- and gender-related differences were evaluated in two neurophysiologic measures of swallowing: MEPs stimulated by single-pulse transcranial magnetic stimulation (TMS) over the motor cortex and surface electromyography (sEMG) recorded from the same submental muscle group during non-stimulated swallows. The older participants had larger MEPs during saliva swallowing than the young participants (p = 0.04, d = 0.86). Conversely, the older participants had lower amplitude submental EMG activity during non-stimulated swallows (p = 0.045, d = 0.67). Gender had no significant effect on MEP magnitude and on submental activity during saliva swallowing. There were no effects of age or gender on MEP latencies. These findings suggest deterioration in muscle function with age in a sample of healthy adults presenting with functional swallowing. We speculate that muscular decline is partially ameliorated by increased cortical activity-i.e., increased submental MEPs-so as to preserve swallowing function in healthy older subjects. These findings emphasize the need for different reference points for evaluation of submental MEPs of different age groups.

A pilot study of high-density electromyographic maps of muscle activity in normal deglutition

While various methods have been used to study physiological aspects of swallowing, few studies have been conducted to investigate the dynamics of a swallowing procedure with the activation pattern of swallowing muscles. In this pilot study we investigated the feasibility of surface electromyographic (sEMG) dynamic topography as a new approach for continuously visualizing muscle activity of normal swallowing. The dynamic sEMG topographies (or potential mappings) of swallowing were constructed with high-density sEMG recordings from three subjects without any swallowing disorders. The root mean square (RMS) of the sEMG signals was calculated as a function of both position and time to produce two-dimension dynamic sEMG maps of the muscle activity during swallowing. The sEMG maps could provide the information about the dynamic characteristics of swallowing muscles, which is accordance with physiological and biomechanical laws of a normal swallowing. With the results of the present study, we might conclude that the dynamic topography would provide a noninvasive means to continuously visualize the distribution of surface EMG signals of complex muscle activities of normal deglutition.

Pharyngeal pressure generation during tongue-hold swallows across age groups

PURPOSE

To compare the effects of the tongue-hold swallowing maneuver on pharyngeal pressure generation in healthy young and elderly research volunteers.

METHOD

Sixty-eight healthy research volunteers (young, n = 34, mean age = 26.8 years, SD = 5.5; elderly, n = 34, mean age = 72.6 years, SD = 4.8; sex equally represented) performed 5 noneffortful saliva swallows and 5 tongue-hold swallows each. Amplitude and duration of pharyngeal pressure were investigated during both swallowing conditions with solid-state pharyngeal manometry at the level of the oropharynx, hypopharynx, and upper esophageal sphincter (UES).

RESULTS

At both pharyngeal levels, tongue-hold swallows produced lower peak pressure compared with saliva swallows. During tongue-hold swallows, UES relaxation pressure was increased in the elders, whereas the younger group displayed a trend toward reduced relaxation pressure. Elderly individuals produced pressure longer during control swallows in the oropharynx and hypopharynx than young individuals.

CONCLUSIONS

The tongue-hold maneuver affects oropharyngeal and hypopharyngeal pressure in the young and elders in similar ways, whereas effects on UES peak relaxation pressure differ between age groups. Reduced pharyngeal peak pressure and increased UES relaxation pressure underscore the notion that tongue-hold swallows should not be performed when bolus is present. Long-term training effects remain to be investigated.

Biochemistry of the anterior, medial, and posterior genioglossus in the aged rat

Age-related tongue weakness may contribute to swallowing deficits in the elderly. One contributing factor may be an alteration in muscle-fiber-type properties with aging. However, it is not clear how muscle fiber types within the aged tongue may vary from those found in young adults, or how fiber types may vary across the anteroposterior axis of the extrinsic tongue muscles. We examined the myosin heavy chain (MHC) composition of anterior, medial, and posterior sections of the genioglossus muscle (GG) in ten old male Fischer 344/Brown Norway rats and compared findings to previously reported data from young adult male rats. Significant differences (p < 0.01) between young adult and old rats were found in the distribution of MHC isoforms along the anteroposterior axis of the muscle. In the anterior, medial, and posterior regions, there was a significantly smaller proportion of type IIb MHC in the old rat GG muscles, while the proportion of type IIx MHC was significantly greater. In the medial region, the proportion of type I MHC was found to be significantly greater in the old rats. Thus, we found a shift to more slowly contracting muscle fibers in the aged rat tongue.

Supracricoid laryngectomy: age influence on long-term functional results

OBJECTIVES/HYPOTHESIS

: Supracricoid laryngectomies (SCL) are conservative surgical techniques for the treatment of selected laryngeal carcinomas, currently adopted also in old patients. Long-term functional results have not been reported in elderly patients. The aim of this study is to compare voice and swallowing in elderly and younger patients following SCL.

STUDY DESIGN

: Cross-sectional study.

METHODS

: Twenty male patients who underwent SCL were recruited in the study; 10 were younger than 65 years at the time of surgery and 10 were older. Video-endoscopic ratings were taken of neoglottic vibration patterns and bolus transit. Voices were perceptually rated using the GIRBAS scale. The maximum phonation time (MPT) and the syllables diadochokinesis were measured. Spectrograms were recorded. All of the patients completed a self-assessment questionnaire for both voice and swallowing. The data obtained from the two groups were compared through the Mann-Whitney test.

RESULTS

: Video-endoscopic ratings of neoglottal vibration and bolus transit showed no difference between the two groups. The perceptual assessment showed a harsh voice in both groups. No significant difference was found for mean syllable diadochokinesis and the mean MPT was 6.3 seconds and 8.8 seconds, respectively in the younger and older group. The mean value of the Yanagihara scale of voice spectrogram was 3.8 and 3.7. Voice and swallowing quality-of-life questionnaires revealed satisfied patients in both age groups.

CONCLUSIONS

: Age by itself does not have a significant impact on long-term functional results following SCL. Meticulous selection of the candidate to SCL allows the application of this surgical technique with adequate long-term functional results. Laryngoscope, 2009.

The impact of aging on eating, drinking, and swallowing function in people with Down's syndrome

Many people with Down's syndrome (DS) experience eating, drinking, and swallowing (EDS) difficulties, which can potentially lead to life-threatening conditions such as malnutrition, dehydration, and aspiration pneumonia. As the life expectancy of people with DS continues to improve, there is an increasing need to examine how the aging process may further affect these conditions. Published research studies have yet to address this issue; therefore, this article draws on the literature in three associated areas in order to consider the dysphagic problems that might develop in aging people with DS. The areas examined are EDS development in children and adolescents with DS, EDS changes associated with aging, and EDS changes associated with dementia of the Alzheimer's type (DAT) because this condition is prevalent in older adults with DS. This article concludes that unlike in the general population, the aging process is likely to cause dysphagic difficulties in people with DS as they get older. Therefore, it is suggested that longitudinal studies are needed to examine the specific aspects of EDS function that may be affected by aging and concomitant conditions in DS.

Rehabilitative management of oropharyngeal dysphagia in acute care settings: data from a large Italian teaching hospital

A high incidence of oropharyngeal dysphagia (OD) in acute-care settings has been reported; however, no data on its management are found in the literature. Here we report the experience with rehabilitative management of OD in a large Italian hospital. The characteristics of inpatients with OD during 2004 have been studied prospectively. For each patient, demographic data, the department referring the patient, the disease causing OD, and the presence of a communication disorder were registered. The swallowing level at the beginning and at the end of rehabilitation were recorded. Of the 35,590 inpatients admitted to San Giovanni Battista Hospital of Turin during 2004, 222 of them were referred for the assessment and rehabilitation of OD. The inpatients with OD came from different departments and mainly had a neurologic disease. In 110 patients a communication disorder was present. The swallowing impairment was moderate to severe at the moment of referral, while on average patients were able to eat by mouth after swallowing therapy. Dysphagia rehabilitation in an acute care setting is requested from different departments because of its prevalence and severity; skilled specialists are needed for early assessment and the best management.

The regulation of masticatory function and food bolus formation

This review emphasizes the following points: 1. The values of the physiological parameters of mastication (number of cycles and total electromyographic activity in the sequence, sequence duration, cycle frequency in the sequence, kinetic characteristics of the cycles) are characteristic of each individual and vary widely from one individual to another. In a given individual their modification reflects an adaptation of mastication to the size of the food bolus, and the hardness and rheological characteristics of the food. 2. The ready-to-swallow food boluses produced by different individuals nevertheless display similar particle size distributions. 3. Ageing entails adaptation of the masticatory function and does not impair swallowing. 4. Observed increase in total electromyographic activity shows that more energy is expended in mastication by full denture wearers. Despite this increased muscle activity, loss of teeth, even if compensated for by complete dentures, hinders the formation of a normal bolus. The food boluses made by denture wearers thus contain many large-size particles. The impaired mastication observed in denture wearers approaches the masticatory disabilities found in persons with neuromotor deficiencies.

Retention of KOH-soluble fluoride on enamel and dentine under erosive conditions—A comparison of in vitro and in situ results

OBJECTIVES

Aim of the study was to investigate the stability of CaF(2)-like precipitates on enamel and dentine under neutral or acidic conditions and to compare in vitro and in situ results.

METHODS

Human enamel and dentine specimens were fluoridated (Elmex fluid, 5 min) and subjected to erosive demineralisation (Sprite light: 3/day each; 30 s in vitro, 2 min in situ) or stored under neutral conditions for 4 (in vitro) or 7 (in situ) days. KOH-soluble fluoride was determined using an ion selective electrode. Between the acid attacks, specimens were stored in remineralisation solution (in vitro) or retained in the oral cavity (four volunteers for enamel and dentine each).

RESULTS

Initially, high amounts of KOH-soluble fluoride were gained (between 77.9+/-12.3 and 96.0+/-46.4 microg/cm2). Under neutral conditions in vitro, a significant decrease on enamel (16.2+/-5.0 microg/cm2) and dentine (18.6+/-10.5 microg/cm2) was found, which was more severe under acidic conditions (6.3+/-3.0 and 5.1+/-2.1 microg/cm2, respectively). Under in situ conditions, KOH-soluble fluoride was strikingly stable on enamel under neutral (42.3+/-12.6 microg/cm2) as well as under acidic conditions (54.1+/-17.4 microg/cm2). On dentine, the dissolution kinetics of KOH-soluble fluoride was similar to the in vitro conditions, but the loss was less severe (45.3+/-12.9 microg/cm2 under neutral and 8.8+/-6.4 microg/cm2 under acidic conditions).

CONCLUSIONS

In vitro, more KOH-soluble fluoride was lost under erosive compared to neutral conditions. The intra-oral environment was considerably protective for CaF2-like precipitates especially on enamel.

Efficacy of swallowing training for residents following stroke

BACKGROUND

The presence of dysphagia is associated with an increased risk of mortality, malnutrition, dehydration, compromised pulmonary function, and disability. Appropriate swallowing training can establish optimal nutritional status and eliminate or reduce the risk of developing medical complications associated with swallowing impairment.

AIM(S) OF THE STUDY

The aim of this study was to examine the functional swallowing and nutritional outcomes of swallowing training in institutionalized stroke residents with dysphagia.

DESIGN AND METHODS

A quasi-experimental parallel cluster design was used. Seven institutions with similar bed sizes were selected. All subjects in the experimental group received a structured swallowing training programme. The subjects in the experimental group (n = 40) received 30 minutes of swallowing training each day for 6 days per week for 8 weeks. The control group (n = 21) did not receive any training.

RESULTS

After swallowing training, mean differences in volume per second, volume per swallow, mid-arm circumference and body weight between pre- and post-training of the experimental group were significantly higher than for the control group, while mean differences in neurological examination and choking frequency during meals for the experimental group were significantly lower than in the control group.

CONCLUSION

This study used objective timed swallowing tests, a swallowing questionnaire, and a neurological examination to evaluate the effects of swallowing training. However, videofluroscopy is generally considered the best method for evaluating the pharyngeal and esophageal stages of swallowing, and introducing this technique is recommended for future studies. Furthermore, it is recommended that nursing professionals should conduct swallowing training protocols in stroke patients to help prevent aspiration from dysphagia.

Prevalence of impaired swallowing in institutionalized older people in taiwan

OBJECTIVES

To investigate the prevalence of impaired swallowing in residents at long-term care facilities (LTCFs) in Taiwan.

DESIGN

A chart review, a structured questionnaire completed at interview, a neurological examination, and a timed swallowing test were used to assess impairment and to gather demographic data.

SETTING

Nine skilled nursing facilities and nine intermediate-care facilities in metropolitan Taipei.

PARTICIPANTS

One thousand two hundred twenty-one conscious and unconscious residents with a mean age of 77.07.

MEASUREMENTS

Impaired swallowing was defined when a subject met two or more of the following criteria: self-report of swallowing difficulty, a score of 2 or more derived from a swallowing questionnaire combined with a neurological examination investigating symptoms and signs of impairment, and coughing/choking during a timed swallowing test or a measured swallowing rate (volume swallowed per second) below the 10th percentile as derived from a gender-based study of an older community in Taipei.

RESULTS

Of the 1,221 subjects, 356 (29.2%) were fed by tube. The prevalence rates for impaired swallowing as estimated were 97.5% and 31.9% for tube-fed and non-tube-fed subjects respectively, whereas the overall prevalence for tube-fed and non-tube-fed subjects altogether was 51.0%.

CONCLUSIONS

The findings may serve to increase awareness of this problem among healthcare professionals in LTCFs. Further research is contemplated to investigate whether early identification makes a difference in treatment choices and outcomes.

Deposition and clearance: unique problems in the proximal airways and oral cavity in the young and elderly

Prospective longitudinal studies measuring aerosol behavior in the respiratory tract as humans age have not been performed. The present paper reviews observations related to aging of the respiratory tract and other effects more likely due primarily to disease and iatrogenic causes. Upper airway deposition was found to approximate 50% in children during inhalation of drugs thought to be designed primarily for deposition in the lower respiratory tract. In older subjects, aging per se did not have a major impact on the deposition of aerosols. Disease processes that develop with age were shown to be the primary cause of deposition abnormalities. Flow-limitation in central airways was proposed as a major factor responsible for central airway deposition as well as abnormal clearance in common obstructive lung diseases. The oral cavity, a source of pathogenic organisms causing pneumonia, was also studied in the elderly. Salivary clearance, often abnormal in the aged, was related to colonization with pathogenic bacteria. Salivary clearance was not obviously reduced by aging per se but by iatrogenic sources such as drug therapy for other diseases.