Repetitive Swallowing Research Articles

Swallowing sound evaluation using an electronic stethoscope and artificial intelligence analysis for patients with amyotrophic lateral sclerosis.

Non-invasive, simple, and repetitive swallowing evaluation is required to prevent aspiration pneumonia in neurological care. We investigated the usefulness of swallowing sound evaluation in patients with amyotrophic lateral sclerosis (ALS) using our new electronic stethoscope artificial intelligence (AI) analysis tool. We studied patients with ALS who provided written informed consent. We used an electronic stethoscope, placed a Bluetooth-enabled electronic stethoscope on the upper end of the sternum, performed a 3-mL water swallow three times, and remotely identified the intermittent sound components of the water flow caused at that time by AI, with the maximum value as the swallowing sound index. We examined the correlation between the swallowing sound index and patient background, including swallowing-related parameters. We evaluated 24 patients with ALS (age 64.0 ± 11.8 years, 13 women, median duration of illness 17.5 months). The median ALS Functional Rating Scale-Revised (ALSFRS-R) score was 41 (minimum 18, maximum 47). In all cases, the mean swallowing sound index was 0.209 ± 0.088. A multivariate analysis showed that a decrease in the swallowing sound index was significantly associated with a low ALSFRS-R score, an ALSFRS-R bulbar symptom score, % vital capacity, tongue pressure, a Mann Assessment of Swallowing Ability (MASA) score, and a MASA pharyngeal phase-related score. Swallowing sound evaluation using an electronic stethoscope AI analysis showed a correlation with existing indicators in swallowing evaluation in ALS and suggested its usefulness as a new method. This is expected to be a useful examination method in home and remote medical care.

Trichotillomania with Trichophagia and Trichobezoars: A Case Report

Trichotillomania is a condition when an individual is unable to resist the urge to pull out the hair on their head or in other places. Trichophagia is the repetitive swallowing of hair most usually connected with compulsive hair pulling. Trichotillomania with trichophagia is a rare psychiatric disease. Trichobezoar, on the other hand, has been documented in several surgical studies. It is unusual to see these symptoms appear at the same time. It can affect anyone at any age, but it is more common in adolescents, with a strong female predominance. This is a case report of an unusual case in an 11-year-old girl with all three disorders occurring at the same time and presenting with intestinal obstruction. This case report aims to identify signs and symptoms of trichobezoar, mainly in adolescents, to discover similar incidents that may link to psychiatric disorders like trichotillomania and trichophagia in medical practices.

Seronegative Myasthenia Gravis Presenting as Dysphagia in a Young Male- A Diagnostic Dilemma

21year old gentleman presented with insidious onset, gradually progressive dysphagia for 2 weeks. There was no other associated signs or symptoms. Initial blood workup, radiological investigations and diagnostic interventions were non-contributory. In the meantime, dysphagia worsened and was found to be progressive with advancement of the day. Oesophageal manometric studies showed gradual weakening of peristaltic contractions after a string of repetitive swallows. Repetitive nerve stimulation test and edrophonium test were suggestive of Myasthenia Gravis; Anti-acetylcholine receptor antibody and anti-MuSK antibody were negative. He was initiated on Pyridostigmine and had improvement of dysphagia after a few days. He has now achieved remission. Hence, we present a curious case of Seronegative Myasthenia Gravis in a young gentleman who presented with only dysphagia recovered with Pyridostigmine.

EndoFLIP Topography: Motor Patterns in an Obstructed Esophagus

EndoFLIP Topography: Motor Patterns in an Obstructed Esophagus

Ingested removable partial denture causing esophageal perforation in a patient with autism: Management and prevention

A 60-year-old woman with autism and a repetitive swallowing behavior ingested a removable partial denture that impacted in the proximal esophagus. Attempts at endoscopic removal were unsuccessful. Esophageal perforation was recognized, necessitating emergency transcervical surgical exploration, esophagotomy with foreign body removal, and repair of the esophageal perforation. She had a prolonged postoperative stay involving mechanical ventilatory support and gastric tube feeds. This situation was predictable and preventable, and application of key principles may help avoid such catastrophic incidents in similar patients.

Noto swallowing project—Repetitive swallowing round to facilities without a speech-language-hearing therapist—

Noto swallowing project—Repetitive swallowing round to facilities without a speech-language-hearing therapist—

An Experimental Swallow Evoked Potential Protocol to Investigate the Neural Substrates of Swallowing.

Advancement in dysphagia intervention is hindered by our lack of understanding of the neural mechanisms of swallowing in health and disease. Evoking and understanding neural activity in response to normal and disordered swallowing is essential to bridge this knowledge gap. Building on sensory evoked potential methodology, we developed a minimally invasive approach to generate swallow evoked potentials (SwEPs) in response to repetitive swallowing induced by citric acid stimulation of the oropharynx in lightly anesthetized healthy adult rats. The SwEP waveform consisted of 8 replicable peaks within 10 milliseconds immediately preceding the onset of electromyographic swallowing activity. Methodology refinement is underway with healthy rats to establish normative SwEP waveform morphology before proceeding to models of advanced aging and age-related neurodegenerative diseases. Ultimately, we envision that this experimental protocol may unmask the pathologic neural substrates contributing to dysphagia to accelerate the discovery of targeted therapeutics.

Dysphagia Prevalence, Attitudes, and Related Quality of Life in Patients with Multiple Sclerosis.

Dysphagia in patients with multiple sclerosis (MS) is associated with significant morbidity and has profound impact on the quality of life (QoL). This study aimed to analyze the dysphagia prevalence, attitudes, and dysphagia-related QoL in patients with MS, not at relapse. A prospective study of 108 consecutively recruited patients. The patients were asked to report dysphagia and completed a general dysphagia questionnaire (the Eating Assessment Tool-10, EAT-10), a disease-specific dysphagia questionnaire (the Dysphagia in Multiple Sclerosis, DYMUS), and a dysphagia-related QoL questionnaire (the Swallowing-Quality of Life). Twenty-six percent of the patients reported dysphagia. Many more were classified as dysphagic by the questionnaires (34.3% by EAT-10 and 44.4% by DYMUS). Overall, one out of four patients reported difficulties or choking while drinking fluids and eating food, cough related to eating, food sticking in the throat, need for food and drink segmentation, and repetitive swallows. The pleasure of eating was found to be moderately affected. The patients seem to cope well with the psychological and social impact of dysphagia. Serious consideration must be given to patients' perceptions and attitudes towards dysphagia. Our patients reported very little fear associated with their swallowing difficulties and choking. Apparently, they do not perceive the severity of their symptoms as an actual danger, as they have developed coping strategies. Dysphagia is common in MS patients not at relapse, even with mild disease-related impairment. Swallowing should be systematically assessed with validated questionnaires in all patients with MS at the course of the disease.

Evaluation of Esophageal Contraction Reserve Using HRM in Symptomatic Esophageal Disease.

Esophageal high resolution manometry (HRM) is the gold standard for assessment of esophageal motor disorders, but motor responses to the standard 5 mL water swallow protocol may not provide precision in defining minor motor disorders. Provocative maneuvers, particularly multiple rapid swallows (MRS), have been used to assess deglutitive inhibition during the repetitive swallows, and the contractile response following the final swallow of the sequence. The augmentation of esophageal smooth muscle contraction following MRS is termed contraction reserve. This is determined as the ratio between esophageal body contraction vigor (distal contractile integral, DCI) following MRS to the mean DCI after single swallows, which is ≥1 in the presence of contraction reserve. Reliable assessment of contraction reserve requires the performance of 3 MRS maneuvers during HRM. Absence of contraction reserve is associated with a higher likelihood of late postfundoplication dysphagia and may correlate with higher esophageal reflux burden on ambulatory reflux monitoring. Esophageal motor responses to abdominal compression, functional lumen imaging probe (FLIP) balloon distension, and pharmacologic testing (using edrophonium and cisapride) may correlate with contraction reserve. Other provocative tests useful during HRM include rapid drink challenge, solid and viscous swallows, and standardized test meals, which are more useful in evaluation of esophageal outflow obstruction and dysphagia syndromes than in identification of contraction reserve. Provocative maneuvers have been recommended as part of routine HRM protocols, and while useful clinical information can be gleaned from these maneuvers, further research is necessary to determine the precise role of provocative testing in clinical esophagology.

Pharyngoesophageal and cardiorespiratory interactions: potential implications for premature infants at risk of clinically significant cardiorespiratory events.

The aims of this study were to 1) examine pharyngoesophageal and cardiorespiratory responses to provoking pharyngeal stimuli, and 2) to determine potential contributory factors impacting heart rate (HR) changes to provide insight into cardiorespiratory events occurring in preterm infants. Forty-eight neonates (19 females and 29 males, born at 27.7 ± 0.5 wk; mean ± SE) pending discharge on full oral feeds were studied at 38.7 ± 0.2 wk postmenstrual age using concurrent pharyngoesophageal manometry, electrocardiography, respiratory inductance plethysmography, and nasal airflow thermistor. Pharyngoesophageal and cardiorespiratory responses (prevalence, latency, and duration) were quantified upon abrupt pharyngeal water stimuli (0.1, 0.3, and 0.5 ml in triplicate). Mixed linear models and generalized estimating equations were used for comparisons between HR changes. Contributory factors included stimulus characteristics and subject characteristics. Of 338 pharyngeal stimuli administered, HR increased in 23 (7%), decreased in 108 (32%), and remained stable in 207 (61%) neonates. HR decrease resulted in repetitive swallowing, increased respiratory-rhythm disturbance, and decreased esophageal propagation rates (all, P < 0.05). HR responses were related to stimulus volume, stimulus flow rate, and extreme prematurity (all, P < 0.05). In preterm infants, HR remains stable in a majority of pharyngeal provocations. HR decrease, due to pharyngeal stimulation, is related to aberrant pharyngoesophageal motility and respiratory dysregulation and is magnified by prematurity. We infer that the observed aberrant responses across digestive, respiratory, and cardiovascular systems are related to maladaptive maturation of the parasympathetic nervous system. These aberrant responses may provide diagnostic clues for risk stratification of infants with troublesome cardiorespiratory events and swallowing difficulty. NEW & NOTEWORTHY Cardiorespiratory rhythms concurrent with pharyngeal, upper esophageal sphincter, and esophageal body responses were examined upon pharyngeal provocation in preterm-born infants who were studied at full-term maturation. Decreased heart rate (HR) was associated with extreme preterm birth and stimulus flow/volume. With HR decrease responses, aerodigestive reflex abnormalities were present, characterized by prolonged respiratory rhythm disturbance, repetitive multiple swallowing, and poor esophageal propagation. Promoting esophageal peristalsis may be a potential therapeutic target.

Central Respiration and Mechanical Ventilation in the Gating of Swallow With Breathing.

Swallow-breathing coordination safeguards the lower airways from tracheal aspiration of bolus material as it moves through the pharynx into the esophagus. Impaired movements of the shared muscles or structures of the aerodigestive tract, or disruptions in the interaction of brainstem swallow and respiratory central pattern generators (CPGs) result in dysphagia. To maximize lower airway protection these CPGs integrate respiratory rhythm generation signals and vagal afferent feedback to synchronize swallow with breathing. Despite extensive study, the roles of central respiratory activity and vagal feedback from the lungs as key elements for effective swallow-breathing coordination remain unclear. The effect of altered timing of bronchopulmonary vagal afferent input on swallows triggered during electrical stimulation of the superior laryngeal nerves or by injection of water into the pharyngeal cavity was studied in decerebrate, paralyzed, and artificially ventilated cats. We observed two types of single swallows that produced distinct effects on central respiratory-rhythm across all conditions: post-inspiratory type swallows disrupted central-inspiratory activity without affecting expiration, whereas expiratory type swallows prolonged expiration without affecting central-inspiratory activity. Repetitive swallows observed during apnea reset the E2 phase of central respiration and produced facilitation of swallow motor output nerve burst durations. Moreover, swallow initiation was negatively modulated by vagal feedback and was reset by lung inflation. Collectively, these findings support a novel model of reciprocal inhibition between the swallow CPG and inspiratory or expiratory cells of the respiratory CPG where lung distension and phases of central respiratory activity represent a dual peripheral and central gating mechanism of swallow-breathing coordination.

New insights into a decerebrate feline model of swallow‐breathing coordination

In the medulla, the swallow and respiratory central pattern generators (CPGs) interact to coordinate swallow initiation and permit swallow execution during the expiratory phase of breathing. Disruption of swallow‐breathing coordination can result in dysphagia, which is a major cause of morbidity and mortality in many neuro‐muscular diseases, especially stroke. Despite extensive study, the precise mechanisms of swallow‐breathing coordination are not known. We tested the hypothesis that both central inspiratory activity and vagal feedback from the lungs are key elements for effective swallow‐breathing coordination. Swallows were triggered by electrical stimulation of the superior laryngeal nerves (SLN) or by injection of water into the pharyngeal cavity in decerebrate, paralyzed and artificially ventilated cats while motor activities were recorded from phrenic, hypoglossal, lumbar and vagal nerves. Mechanical ventilation was either triggered by central inspiratory activity or set independently from the phrenic activity to alter the timing of bronchopulmonary vagal afferent input and allow analysis of its influence on swallow‐breathing coordination. We observed two types of swallows that produced opposite effects on central respiratory‐rhythm resetting across all conditions: post‐Inspiratory type swallows disrupted central I activity without affecting expiration, whereas expiratory type swallows prolonged expiration without affecting central inspiratory activity. Repetitive swallows observed during apnea reset the E2 phase of central respiration and produced facilitation of swallow motor output. Moreover, swallow initiation was negatively modulated by vagal feedback and was reset by lung inflation. Collectively, these findings support a reciprocal inhibition between central inspiration and the swallow CPG and they are consistent with a role for pulmonary stretch receptors in the coordination between brainstem CPGs for breathing and swallowing. They may also prove relevant for healthcare management of dysphagia.Support or Funding InformationOT2OD023854‐01, HL109025This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Differences in brain networks during consecutive swallows detected using an optimized vertex–frequency algorithm

Patients with dysphagia can have higher risks of aspiration after repetitive swallowing activity due to the “fatigue effect”. However, it is still unknown how consecutive swallows affect brain activity. Therefore, we sought to investigate differences in swallowing brain networks formed during consecutive swallows using a signal processing on graph approach. Data were collected from 55 healthy people using electroencephalography (EEG) signals. Participants performed dry swallows (i.e., saliva swallows) and wet swallows (i.e., water, nectar-thick, and honey thick swallows). After standard pre-processing of the EEG time series, brain networks were formed using the time–frequency-based synchrony measure, while signals on graphs were formed as a line graph of the brain networks. For calculating the vertex frequency information from the signals on graphs, the proposed algorithm was based on the optimized window size for calculating the windowed graph Fourier transform and the graph S-transform. The proposed algorithms were tested using synthetic signals and showed improved energy concentration in comparison to the original algorithm. When applied to EEG swallowing data, the optimized windowed graph Fourier transform and the optimized graph S-transform showed that differences exist in brain activity between consecutive swallows. In addition, the results showed higher differences between consecutive swallows for thicker liquids.

Sleep Stage Coordination of Respiration and Swallowing: A Preliminary Study.

Swallowing is an important physiological response that protects the airway. Although aspiration during sleep may cause aspiration pneumonia, the mechanisms responsible have not yet been elucidated. We evaluated the coordination between respiration and swallowing by infusing water into the pharynx of healthy young adults during each sleep stage. Seven normal subjects participated in the study. During polysomnography recordings, to elicit a swallow we injected distilled water into the pharynx during the awake state and each sleep stage through a nasal catheter. We assessed swallow latency, swallow apnea time, the respiratory phase during a swallow, the number of swallows, and coughing. A total number of 79 swallows were recorded. The median swallow latency was significantly higher in stage 2 (10.05s) and stage 3 (44.17s) when compared to awake state (4.99s). The swallow latency in stage 3 showed a very wide interquartile range. In two subjects, the result was predominantly prolonged compared to the other subjects. There was no significant difference in the swallow apnea time between sleep stages. The presence of inspiration after swallowing, repetitive swallowing, and coughing after swallowing was more frequent during sleep than when awake. This study suggests that the coordination between respiration and swallowing as a defense mechanism against aspiration was impaired during sleep. Our results supported physiologically the fact that healthy adult individuals aspirate pharyngeal secretions during sleep.

Effects of laryngeal restriction on pharyngeal peristalsis and biomechanics: Clinical implications.

To date, rehabilitative exercises aimed at strengthening the pharyngeal muscles have not been developed due to the inability to successfully overload and fatigue these muscles during their contraction, a necessary requirement for strength training. The purpose of this study was to test the hypothesis that applying resistance against anterosuperior movement of the hyolaryngeal complex will overload the pharyngeal muscles and by repetitive swallowing will result in their fatigue manifested by a reduction in pharyngeal peristaltic amplitude. Studies were done in two groups. In group 1 studies 15 healthy subjects (age: 42 ± 14 yr, 11 females) were studied to determine whether imposing resistance to swallowing using a handmade device can affect the swallow-induced hyolaryngeal excursion and related upper esophageal sphincter (UES) opening. In group 2, an additional 15 healthy subjects (age 56 ± 25 yr, 7 females) were studied to determine whether imposing resistance to the anterosuperior excursion of the hyolaryngeal complex induces fatigue manifested as reduction in pharyngeal contractile pressure during repeated swallowing. Analysis of the video recordings showed significant decrease in maximum deglutitive superior laryngeal excursion and UES opening diameter (P < 0.01) due to resistive load. Consecutive swallows against the resistive load showed significant decrease in pharyngeal contractile integral (PhCI) values (P < 0.01). Correlation analysis showed a significant negative correlation between PhCI and successive swallows, suggesting "fatigue" (P < 0.001). In conclusion, repeated swallows against a resistive load induced by restricting the anterosuperior excursion of the larynx safely induces fatigue in pharyngeal peristalsis and thus has the potential to strengthen the pharyngeal contractile function.

Frequency Dependent Inhibitory Mechanisms Controlling the Laryngeal Adductor Response (LAR)

Electrical stimulation of the superior laryngeal nerve (SLN) has been used to induce behaviors with airway protective components, such as the LAR. The LAR has both short (R1) and long latency (R2) peaks in response to stimulation, but the neuronal pathways that produce and modulate the LAR are not well understood. It has been reported that there exists a frequency‐dependent suppression of R2 for SLN stimulation frequencies above 2.5 Hz. The R1 can follow frequencies of electrical stimulation of the SLN approaching 200 Hz, suggesting a high fidelity of brainstem neuronal pathways, but to our knowledge there is no report on whether R1 exhibits frequency‐dependent depression. We hypothesized that the R1 would exhibit frequency‐dependent depression consistent with the existence of modulatory short latency inhibitory mechanisms. To test this hypothesis, we monitored EMG activity from the thyroarytenoid (TA) muscle and electrically stimulated the SLN unilaterally with a range of frequencies between 1 and 40 Hz. All frequencies employed induced both repetitive swallowing and LAR. The R1 peak of the LAR was time‐locked to each stimulus pulse (peak R1 latencies were 13.7±0.5 ms (5–10 Hz) and 14.2±0.6 ms (35–40 Hz)), and the R2 peak was not observed. Lower frequency stimulations (5–10 Hz) of the SLN elicited significantly higher LAR amplitudes (52.8 ±2.9 % max) than higher frequency stimulations (35–40 Hz; 36.8±3.2 % max). In other experiments, analysis of neuronal responses recorded in the ventral respiratory column revealed evidence of stimulus‐induced synchrony as well as disruption of concurrent functional relationships among respiratory‐modulated neurons. These observations suggest that more complex regulatory mechanisms exist in addition to frequency‐dependent depression of the LAR.Support or Funding InformationSupported by NIH HL 103415, HL 111215, HL109025.

Role of the dorsal medulla in the neurogenesis of airway protection

The dorsal medulla encompassing the nucleus of the tractus solitarius (NTS) and surrounding reticular formation (RF) has an important role in processing sensory information from the upper and lower airways for the generation and control of airway protective behaviors. These behaviors, such as cough and swallow, historically have been studied in isolation. However, recent information indicates that these and other airway protective behaviors are coordinated to minimize risk of aspiration. The dorsal medullary neural circuits that include the NTS are responsible for rhythmogenesis for repetitive swallowing, but previous models have assigned a role for this portion of the network for coughing that is restricted to monosynaptic sensory processing. We propose a more complex NTS/RF circuit that controls expression of swallowing and coughing and the coordination of these behaviors. The proposed circuit is supported by recordings of activity patterns of selected neural elements in vivo and simulations of a computational model of the brainstem circuit for breathing, coughing, and swallowing. This circuit includes separate rhythmic sub-circuits for all three behaviors. The revised NTS/RF circuit can account for the mode of action of antitussive drugs on the cough motor pattern, as well as the unique coordination of cough and swallow by a meta-behavioral control system for airway protection.

Effect of aging on oral and swallowing function after meal consumption.

Background/purposeDysphagia may worsen due to fatigue of the infrahyoid and suprahyoid muscle groups as a result of repetitive swallowing during a meal. We investigated the hypothesis that meal consumption may reduce tongue strength and endurance in older adults (OAs).MethodsTongue–palate pressure, oral diadochokinesis, repetitive saliva swallowing, and surface electromyography activity before and after a meal were measured in 23 young adults (YAs) and 23 OA volunteers.ResultsThere was a statistically significant difference in both tongue pressure and the number of voluntary swallows between YAs and OAs. Peak tongue pressure was significantly lower in OAs than YAs both before and after meal consumption. The most notable finding was that the first time interval (the time from test initiation to the beginning of the first swallow) was prolonged after meal consumption only in OAs, whereas the first time interval showed no difference between YAs and OAs before meal consumption with reference to the repetitive saliva swallowing test. The initiation of swallowing was prolonged by both meal consumption and aging; there was a significant interaction between these two factors. The number of repetitions of the monosyllable/pa/was statistically similar between YAs and OAs before meal consumption, but it was significantly lower in OAs after meal consumption.ConclusionAging leads to declining tongue pressure and motor function of the lips. It is possible that swallowing function declines in older individuals when meal consumption is prolonged, especially at the end of mealtime, as a result of their efforts in mastication and swallowing.

Effects of 2 different swallowing exercise regimens during organ‐preservation therapies for head and neck cancers on swallowing function

This study investigated the effects of 2 different swallowing exercise regimens performed during radiation therapy with/without chemotherapy on swallowing function. Fifty patients were recruited prospectively to 2 groups (the exercise group, n = 26 and the repetitive swallow group, n = 24). Functional Oral Intake Scale (FOIS) scores and percutaneous endoscopic gastrostomy (PEG) placements were compared at posttreatment and at 3 months. The exercise group eliminated significantly more PEG tubes at 3 months posttreatment compared to the swallow group (16% vs 50%). Among patients who received both radiation and chemotherapy, the exercise group had significantly less PEG tubes immediately posttreatment as well as 3 months posttreatment (35% and 10%), compared to the swallow group (69% and 50%). Findings indicate significant benefits of the exercise group's exercise regimen in reducing PEG dependence and oral intake difficulties.

La disfagia en la enfermedad de Huntington: propuesta de intervención logopédica

IntroductionHuntington disease (HD) is a progressive neurodegenerative autosomal dominant disease characterized by motor, behavioral and cognitive disturbances. Dysphagia is a common and life-threatening symptom of the disease leading to nutritional deficiencies and a high risk of bronchoaspiration. Our objective was to study swallowing dysfunction and to present a specific intervention to improve or maintain swallowing efficiency. Materials and methodsWe recruited 10ambulatory HD patients aged between 46 and 79years old, with a moderate stage of the disease, who were compared with 10 age- and gender-matched healthy controls. The safety and effectiveness of the oral and pharyngeal phases was assessed qualitatively and quantitatively through the volume-viscosity swallow test. ResultsWe observed ineffective lip closure in 6patients, oral residue in 4, repetitive swallows in 10, pharyngeal residue in 7, cough in 3, voice changes in 6, and a drop of 2points in blood oxygen saturation in a further 3. Controls scored between 60 and 63points, while patients scored between 19 and 53points. ConclusionsThe oral and pharyngeal swallowing phases are already compromised in moderate stages of HD. We hypothesize that a specific rehabilitation program for dysphagia could improve swallowing difficulties and contribute to maintaining nutritional status in affected individuals. Consequently, we propose a rehabilitation program including orolingual praxis and specific muscular postural strategies.