Continuous Swallowing Research Articles

Evaluation of morphological features of palatopharyngeus insertion into the thyroid cartilage.

The attachment of the palatopharyngeus extended from the posterior end of the thyroid cartilage to the posterior margin of the inferior constrictor attachment that might contribute to successive swallowing movements. Laryngeal elevation is essential for proper swallowing and breathing. Recently, clinical research has demonstrated that the palatopharyngeus, a longitudinal muscle of the pharynx, is involved in the elevation of the larynx. However, the morphological relationship between the larynx and palatopharyngeus remains unclear. In the present study, we analyzed the attachment site and characteristics of the palatopharyngeus in the thyroid cartilage. We evaluated 14 halves of seven heads from Japanese cadavers (average age: 76.4years); 12 halves, anatomically and two halves histologically. A part of the palatopharyngeus, which originated from the inferior aspect of the palatine aponeurosis, was attached to the inner and outer surfaces of the thyroid cartilage through collagen fibers. The attachment area extends from the posterior end of the thyroid cartilage to the posterior margin of the attachment site of the inferior constrictor. The palatopharyngeus may elevate the larynx with the suprahyoid muscles and contribute to successive movements of swallowing with surrounding muscles. Based on our findings and previous studies, palatopharyngeus with various muscle bundle directions may be essential for the coordination of continuous swallowing events.

P 44 Restitution of oral transport, penetration, and aspiration with nigral stimulation in Parkinson's disease?

Introduction: Dysphagia is common in advanced Parkinson's disease (PD) leading to aspiration and pneumonia. These complications are relevant for quality of life of patients and increase morbidity and mortality. Standard treatment such as dopaminergic medication and deep brain stimulation of subthalamic nucleus (STN) often fall short to improve dysphagia. Stimulation of the substantia nigra pars reticulata (SNr) is of interest in dysphagia since experimental models suggested that SNr might be involved to swallowing. Here, we hypothesized that the combined stimulation of STN and SNr improves dysphagia compared with standard subthalamic nucleus stimulation at eight weeks of treatment. Patients and Methods: We enrolled PD patients with dysphagia. After a screening visit, the eligible patients entered an eight-week active treatment phase. Patients were assessed in “medication on” and “standard STN” at baseline (V1) and then were randomized 1:1 “standard STN” or “STN+SNr”. During the 8-week follow-up the participants received swallowing therapy as a standard care therapy in addition. After eight-weeks we evaluated swallowing function and clinical measures in a follow-up visit (V2). We focused on the oral and pharyngeal phase of swallowing. Our primary endpoint was the Penetration-Aspiration Scale (PAS). Additional to PAS, a visual analog scale (VAS) for pharyngeal residue in vallecular space and sinus piriformes and Site of Swallow Reflex Initiation (SOS) provided us further information about pharyngeal phase, penetration, and aspiration. We chose the “Test of Mastication and Swallowing Solids” (TOMASS) to study oral preparation and transport, SWAL-QoL scale for dysphagia-associated quality of life, and Functional oral intake scale (FOIS) for functional dimension. Results: We enrolled 20 patients. The PAS showed no significant difference in change from baseline between groups (P = 0.221). As secondary finding, we found that both patients from the STN and STN+SNr group showed better PAS at V2 compared to V1. VAS score for pharyngeal residue in sinus piriformes for solid food showed better outcome in “standard STN” group compared to “STN+SNr” group compared with baseline as well (P= 0.011). A difference of the number of swallows in the TOMASS score was found with lower number of swallows in the STN group (P = 0.025). Other outcome measures showed no difference between the groups. Conclusion: Our study did not show a superior effect of STN+SNr compared to STN. However, we found that the patients globally improved with dysphagia irrespective from the stimulation condition. This probably reflected the effect of continuous swallowing therapy and the increased patients‘ awareness towards swallowing. A closer pathophysiological understanding of the neuronal circuitry is therefore needed for specific neuromodulation intervention.

Cortical Activation of Swallowing Using fNIRS: A Proof of Concept Study with Healthy Adults.

The purpose of this study was to determine whether functional near-infrared spectroscopy (fNIRS) could reliably identify cortical activation patterns as healthy adults engaged in single sip and continuous swallowing tasks. Thirty-three right-handed adults completed two functional swallowing tasks, one control jaw movement task, and one rest task while being imaged with fNIRS. Swallowing tasks included a single sip of 5mL of water via syringe and continuous straw drinking. fNIRS patches for acquisition of neuroimaging data were placed parallel over left and right hemispheres. Stimuli presentation was controlled with set time intervals and audio instructions. Using a series of linear mixed effect models, results demonstrated clear cortical activation patterns during swallowing. The continuous swallowing task demonstrated significant differences in blood oxygenation and deoxygenation concentration values across nearly all regions examined, but most notably M1 in both hemispheres. Of note is that there were areas of greater activation, particularly on the right hemisphere, when comparing the single sip swallow to the jaw movement control and rest tasks. Results from the current study support the use of fNIRS during investigation of swallowing. The utilization of healthy adults as a method for acquiring normative data is vital for comparison purposes when investigating individuals with disorders, but also in the development of rehabilitation techniques. Identifying activation areas that pertain to swallowing will have important implications for individuals requiring dysphagia therapy.

Electrical activity of the masseter and supra hyoid muscles during swallowing of patients with multiple sclerosis.

characterize the swallowing muscles electromyographic activity in EM. we evaluated 60 individuals being 30 with definitive diagnosis in EMG and 30 without neurologic changes. Volunteers provided personal data through interview, and we also obtained data from clinical records on the time of diagnosis, disease clinic form and the EDSS scale score. We then administered the DYMUS questionnaire. All evaluations occurred according to the Swallowing Electromyographic Evaluation Protocol. Saliva swallowing, liquid swallowing with comfortable volume and continuous swallowing showed differences in the groups at the masseter, with higher averages in the comparison group. We verified differences between masseter and supra hyoid in each group, at rest, in saliva swallowing, liquid swallowing with comfortable volume and continued swallowing. In all situations the averages were higher in the supra hyoid, being that the smaller difference occurred at rest and the higher at continuous swallow. We recorded correlations between EDSS and the activity of supra hyoid at saliva swallow, liquid swallow with comfortable volume and swallow continuous. With the DYMUS, we observed correlations with the masseter activity and with the swallowing time. The high punctuation at the DYMUS presented correlations with the increase electrical activity of the masseter. patients with more severe conditions show lower supra hyoid electric activity, and the electric activity of the masseter is related to difficulty in swallowing.

Automatic detection of oral and pharyngeal phases in swallowing using classification algorithms and multichannel EMG

Swallowing is a complex process that involves sequential voluntary and involuntary muscle contractions. Malfunctioning of swallowing related muscles could lead to dysphagia. However, there is a lack of standardized and non-invasive methods that support and improve the diagnosis and ambulatory care.This paper presents a classification scheme of two swallowing phases (oral and pharyngeal) based on signals of surface electromyography (sEMG). Eight acquisition channels recorded the EMG activity of 47 healthy subjects while they swallowed water, yogurt and saliva. Every signal was processed, segmented and labeled with background activity, oral or pharyngeal classes. Nine time domain and four frequency domain features were extracted from the segments, assessed individually and then compared in groups according to a correlation analysis. A support vector machine (SVM) with radial basis function kernel and a feedforward artificial neural network (ANN) with one hidden layer were used as classifiers.Different hyperparameters of the SVM and number of hidden neurons of the ANN were assessed for the proposed scheme. The recognition accuracy of SVM (92,03%) was higher than ANN’s (90,26%). Time domain features were found to have better capability of representation than their frequency domain counterpart. Nevertheless, expanding the feature space improved the performance of the classifiers.Experimental results show that proposed sEMG-based method can correctly distinguish between oral and pharyngeal swallowing phases and can be used for assessment of continuous swallowing tasks. This paper extends previous reported findings to small muscles with low signal-to-noise ratio and high crosstalk acquired in multichannel systems.

Swallow segmentation with artificial neural networks and multi-sensor fusion

Swallow segmentation is a critical precursory step to the analysis of swallowing signal characteristics. In an effort to automatically segment swallows, we investigated artificial neural networks (ANN) with information from cervical dual-axis accelerometry, submental MMG, and nasal airflow. Our objectives were (1) to investigate the relationship between segmentation performance and the number of signal sources and (2) to identify the signals or signal combinations most useful for swallow segmentation. Signals were acquired from 17 healthy adults in both discrete and continuous swallowing tasks using five stimuli. Training and test feature vectors were constructed with variances from single or multiple signals, estimated within 200 ms moving windows with 50% overlap. Corresponding binary target labels (swallow or non-swallow) were derived by manual segmentation. A separate 3-layer ANN was trained for each participant–signal combination, and all possible signal combinations were investigated. As more signal sources were included, segmentation performance improved in terms of sensitivity, specificity, accuracy, and adjusted accuracy. The combination of all four signal sources achieved the highest mean accuracy and adjusted accuracy of 88.5% and 89.6%, respectively. A–P accelerometry proved to be the most discriminatory source, while the inclusion of MMG or nasal airflow resulted in the least performance improvement. These findings suggest that an ANN, multi-sensor fusion approach to segmentation is worthy of further investigation in swallowing studies.

Effects of Taste Solutions, Carbonation, and Cold Stimulus on the Power Frequency Content of Swallowing Submental Surface Electromyography

This study explored the effects of 5 taste solutions (citric acid, sucrose, sodium chloride, caffeine, and sodium glutamate) versus water on the power frequency content of swallowing submental surface electromyography (sEMG). Healthy subjects were presented with 5 ml of each of 5 tastants and water. Data were collected in 3 trials of the 5 tastants and water by using submental sEMG, which was then subjected to spectral analysis. Sour and salt taste solutions increased the spectrum-integrated values of the total power components. The spectrum-integrated values of low-frequency power (below 10 Hz) in the salt taste trial significantly increased, whereas those of high-frequency power (above 10 Hz) in the sour taste trial tended to increase. Neither pleasantness nor intensity of taste was related to these changes. This study also explored the effects of carbonation and cold stimulus on the power frequency content of continuous swallowing sEMG for 60-ml solutions. Carbonation significantly increased the spectrum-integrated value of the total power components by significantly increasing the high-frequency content. Cold stimulus significantly decreased the low-frequency content. In summary, this study reveals that taste, carbonation, and cold stimulus have qualitatively different influences on the power frequency content of swallowing sEMG.

Cortical Representation of Swallowing: A Modified Dual Task Paradigm

It is unclear whether the cortical representation of swallowing is lateralized to the left cerebral hemisphere, right hemisphere, or bilaterally represented. As dysphagia is common in acute stroke, it is important to elucidate swallowing lateralization to facilitate earlier detection of stroke patients who may be at greater risk for dysphagia and aspiration. In this study, a modified dual task paradigm was designed to study laterality of swallowing in a group of 14 healthy, young, right-handed, male adults. The subjects were studied at baseline and with interference. Baseline conditions, performed separately, were continuous swallowing, finger tapping using the right and left index fingers, and word repetition. Interference tasks, including tapping with the right index finger, tapping with the left index finger, and word repetition, were completed with and without swallowing. Finger-tapping rate was measured, and x-ray samples of the swallowing task were taped to measure swallowing rate and volume swallowed. At baseline, the rate of tapping the right index finger was significantly faster than that of the left index finger. There was a significant decline in the tapping rates of both left and right index fingers with swallowing interference. The volume per swallow was significantly reduced during the interfering language task of silent repetition. These results offer partial support for a bilateral representation of swallowing as well as suggest an important left hemispheric contribution to swallowing. However, it cannot be concluded that the left hemisphere is more important than the right, as a comparable right hemisphere task was not studied.

Swallow-induced alterations in breathing in normal older people.

Respiratory parameters in 29 normal older subjects (mean age-73 years, SD = 5.7) were studied at rest, during single water swallows, and in continuous drinking. Respiration was recorded by intranasal air pressure changes and the moment of swallowing by pharyngoesophageal manometry. Compared with respiration at rest, respiratory rate increased immediately after 5 mL swallows as duration of breath cycles decreased from a mean of 3.8 s at rest to 3.5 s after swallowing (p = 0.003), but regularity of respiration was maintained. Deglutition apnea showed a trend toward increasing duration from a median of 1.06 to 1.24 s (p = 0.096) as bolus volume increased from 5 to 20 mL. Oxygen saturation levels were also compared, with a median fall of 2% during swallowing, but with larger and unexplained falls in several subjects. Direction of airflow monitoring showed 91% of single 5 mL swallows were followed by expiration, with postswallow inspiratory breaths occurring in 41% of subjects. Continuous swallowing of 100 mL of water from a cup and straw was typically performed with a pattern of multiple swallows per breath, with expiration occurring after 78.5% (cup) and 63.5% (straw) of swallows. This definition of swallowing-induced respiratory changes in normal older people forms a valuable basis for future comparison with elderly dysphagic patients.

CORTICAL REPRESENTATION OF SWALLOWING: A MODIFIED DUAL TASK PARADIGM

It is unclear whether the cortical representation of swallowing is lateralized to the left cerebral hemisphere, right hemisphere, or bilaterally represented. As dysphagia is common in acute stroke, it is important to elucidate swallowing lateralization to facilitate earlier detection of stroke patients who may be at greater risk for dysphagia and aspiration. In this study, a modified dual task paradigm was designed to study laterality of swallowing in a group of 14 healthy, young, right-handed, male adults. The subjects were studied at baseline and with interference. Baseline conditions, performed separately, were continuous swallowing, finger tapping using the right and left index fingers, and word repetition. Interference tasks, including tapping with the right index finger, tapping with the left index finger, and word repetition, were completed with and without swallowing. Finger-tapping rate was measured, and x-ray samples of the swallowing task were taped to measure swallowing rate and volume swallowed. At baseline, the rate of tapping the right index finger was significantly faster than that of the left index finger. There was a significant decline in the tapping rates of both left and right index fingers with swallowing interference. The volume per swallow was significantly reduced during the interfering language task of silent repetition. These results offer partial support for a bilateral representation of swallowing as well as suggest an important left hemispheric contribution to swallowing. However, it cannot be concluded that the left hemisphere is more important than the right, as a comparable right hemisphere task was not studied.

Hypercapnia enhances the development of coughing during continuous infusion of water into the pharynx.

We investigated the effects of increasing CO2 ventilatory drive on the coordination of respiration and reflex swallowing elicited by continuous infusion of distilled water into the pharynx (2.5 ml/min) in 11 normal subjects. Ventilation was monitored using a pneumotachograph and swallowing was recorded by submental electromyogram. The CO2 ventilatory drive was increased by addition of external dead space, while ventilation, the frequency of swallows, and the timing of swallows in relation to the phases of the respiratory cycle were measured at steady-state conditions. We found that the CO2 ventilatory response is not influenced by continuous reflex swallowing but that hypercapnia influences the timing and frequency of these swallows. Signs of aspiration were never observed during continuous infusion of water at eucapnia, but seven of 11 subjects showed laryngeal irritation and/or pending aspiration during hypercapnia, and the incidence of laryngeal irritation was higher the greater the PCO2. Detailed analysis of laryngeal irritations consisting of single coughs in seven subjects revealed that the majority of laryngeal irritations occurred when swallows coincided with expiratory-inspiratory transition or when swallows coincided with inspiration, whereas laryngeal irritation after an expiratory swallow was never observed. These results suggest that the automatic respiratory control system is not influenced by continuous swallowing but that the coordination of swallowing and respiration may be compromised during hypercapnia.

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We conducted experiments to determine the changes in swallowing attributable to differences in the property of the materials to be swallowed. The maximum swallowing capacity for water and 2% Throughsoft STM (an aqueous solution containing a starch power) was always larger by about by 20 ml for water than for 2% Throughsoft STM, though the absolute amount swallowed varied with each individual. On the other hand, the concept of ease in swallowing, presumably involving a light load was advanced in this study. Bolus volume of each swallow during continuous swallowing was close to that of easy swallowing. The volume did not apparently differ from that of water nor that of 2% Throughsoft STM. These results seem to suggest that the root of the tongue judges the property of the material to be swallowed before the completion of the stage II of swallowing, at latest, and actively determines the appropriate amount of material to be swallowed.

Control of ventilation during continuous swallowing.

The upper airway performs three distinct functions that must be coordinated to allow maximal operation of each individual system. We tested the ventilatory response to progressive hypercapnia in seven normal adults during continuous swallowing. Swallowing was induced by oral infusion of water while the subject breathed through the nose. Infusion of 40 ml/min resulted in repetitive swallows (rate: 8.1 +/- 4.1 swallows/min, mean +/- SD), but this did not cause a single incidence of coughing or aspiration. Swallows interrupted inspiration and expiration and resulted in compensatory changes in tidal volume and breathing frequency. Continuous drinking did not significantly change the slope of the ventilatory response to hypercapnia. The test was repeated in three subjects swallowing water infused at 60, 80, and 100 ml/min. The slope of the response was also not significantly different from control in these tests. We conclude that continuous swallowing does not override ventilatory control mechanisms in human adults.

Effect of continuous swallowing on respiration

We examined the effect of continuous swallowing on breathing pattern and ventilation in 7 adult subjects. Repetitive swallowing was induced by oral infusion of water at a variable rate of 40, 60, 80 or 100 ml/min, while the subject breathed through the nose. The number of swallows increased from a mean of 5.2 (±2.7 SD) swallows/min during the control period to 9.2 ± 2.0 to 13.7 ± 2.9 swallows/min during infusion of 40 and 100 ml/min, respectively. The duration of interruption of breathing was bolus volume-dependent, increasing from 0.55 ± 0.99 sec with a mean bolus volume of 4.6 ± 1.4 ml to 0.87 ± 0.23 sec with a bolus volume of 8.1 ± 1.9 ml. The majority of swallows (73 ± 12%) interrupted breathing during inspiration. The mean tidal volume, inspiratory and expiratory times during swallowing periods were higher than those recorded during the control period, but the mean level of ventilation was not different from control, at all swallowing frequencies. Repetitive swallowing did not result in a single incidence of aspiration or coughing. We conclude that mechanisms integrating breathing and swallowing allow repetitive swallowing to occur without compromising ventilation, and that these mechanisms perfectly orchestrate between breathing and deglutition to prevent aspiration.

A tongue pellet for use in ultrasound imaging

A 5‐mm stainless steel ball bearing was affixed to the tongue using dental impression material and imaged visually with real time ultrasound. The pellet was used to measure movement at a single point on the tongue surface during speech and swallowing gestures. The pellet was placed at midline, a measured distance posterior to the tongue tip. Methodological validation of the visibility and positioning of the pellet was determined from phantom measurements. Pellet movements during speech were found to define superior/inferior and anterior/posterior tongue movements. Our data suggest, however, that these movements do not always represent the point of maximum interest on the tongue surface. Measurements made during swallowing indicate that for both single swallows (20 cc H2O) and continuous swallows pellet movement over time contains transverse and longitudinal wave components. Greater tongue excursion occurred during continuous swallowing. The advantages and limitations of using a pellet will be discussed. Future applications will be mentioned.

A 'Supersalivation Syndrome'

To the Editor.— For about ten years I have had an esophageal reflux syndrome characterized by recurrent epigastric distress, "heartburn," and awakening at night with sour regurgitation and rather severe epigastric pain. The pain, also sometimes present in the lower retrosternal area, feels like a spasm. What has been striking, however, is the remarkable, exuberant outpouring of saliva that occurs with the pain. They go together when the pain is more severe; milder pains may not be associated with the salivary hyperfunction. When it occurs, the salivary outpouring forces almost continuous swallowing and at times is itself more disconcerting than the pain. The epigastric and lower retrosternal pain is relieved by sitting up and drinking hot water or by sucking on an antacid tablet. Even the severe pain is relieved in a few minutes, although a vague residual discomfort may persist for up to 30 minutes. All the symptoms are

Control of ventilation during speech

ARTICLESControl of ventilation during speechJ. C. Bunn, and J. MeadJ. C. Bunn, and J. MeadPublished Online:01 Dec 1971https://doi.org/10.1152/jappl.1971.31.6.870MoreSectionsPDF (764 KB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInEmailWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformationCited ByOptoelectronic Plethysmography has Improved our Knowledge of Respiratory Physiology and Pathophysiology5 December 2008 | Sensors, Vol. 8, No. 12Effects of hypercapnia and hypocapnia on ventilatory variability and the chaotic dynamics of ventilatory flow in humansMarie-Noëlle Fiamma, Christian Straus, Sylvain Thibault, Marc Wysocki, Pierre Baconnier, and Thomas Similowski1 May 2007 | American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, Vol. 292, No. 5Facilitation of the diaphragm response to transcranial magnetic stimulation by increases in human respiratory driveC. Straus, C. Locher, M. Zelter, J.-P. Derenne, and T. Similowski1 September 2004 | Journal of Applied Physiology, Vol. 97, No. 3Oscillations of heart rate and respiration synchronize during poetry recitationDirk Cysarz, Dietrich von Bonin, Helmut Lackner, Peter Heusser, Maximilian Moser, and Henrik Bettermann1 August 2004 | American Journal of Physiology-Heart and Circulatory Physiology, Vol. 287, No. 2Comparative Effects of Two Ventilatory Modes on Speech in Tracheostomized Patients with Neuromuscular DiseaseAmerican Journal of Respiratory and Critical Care Medicine, Vol. 167, No. 2The effects of speech production on physiologic responses during submaximal exerciseMedicine & Science in Sports & Exercise, Vol. 34, No. 8Modulation of the corticospinal control of ventilation by changes in reflex respiratory driveD. R. Corfield, C. A. Roberts, A. Guz, K. Murphy, and L. Adams1 November 1999 | Journal of Applied Physiology, Vol. 87, No. 5Effect of continuous swallowing on respirationRespiration Physiology, Vol. 95, No. 2Inspiratory Speech as a Management Option for Spastic Dysphonia29 June 2016 | Annals of Otology, Rhinology & Laryngology, Vol. 101, No. 5The limitation of exercise ventilation during speechRespiration Physiology, Vol. 46, No. 2Periodic Rhythms in Conversational Speech18 August 2016 | Language and Speech, Vol. 22, No. 4 More from this issue > Volume 31Issue 6December 1971Pages 870-872 Copyright & PermissionsCopyright © 1971 the American Physiological Societyhttps://doi.org/10.1152/jappl.1971.31.6.870PubMed5123666History Published online 1 December 1971 Published in print 1 December 1971 Metrics

Food selection by silkworm larvae.

THIS communication reports the presence of three stimulants in mulberry leaves which induce their preferential selection as food by silkworm larvae. The first, which attracts the larvae on to these leaves, has been identified as β,γ-hexenol or α,β-hexenal by T. Watanabe1 ; the second, which stimulates biting action, occurs in the methanol-soluble fraction of the leaves; and the third, which appears to stimulate continuous swallowing by the larvae, is present in the fraction insoluble in methanol and soluble in water. A combination of these factors is of importance for the positive acceptance of food by silkworm larvae. By the use of these stimulants, extracted chemically from mulberry leaves, larvae have been induced to feed on agar.

An electromyographic analysis of reflex deglutition.

An electromyographic analysis of reflex deglutition.