Bulbar function in spinal muscular atrophy (SMA): State of art and new challenges. 21st July 2023, Rome, Italy.

Progressive bulbar involvement is frequent in spinal muscular atrophy, with prevalence and severity of deficits associated with type. The report provides an overview of the presentations made at the workshop grouped into 4 sessions: the first section was dedicated to videofluoroscopy with a revision of the existing protocols and discussion on which one should be used in routine clinical practice and in research settings. The second session was dedicated to interprofessional routine assessments of bulbar function, with a review of the recent clinical tools specifically developed for SMA. The third section was focused on the assessments performed by speech and language therapists/pathologists in the new SMA phenotypes. The last section focused on how the new therapies have changed the approach in rehabilitation for bulbar dysfunction. Finally, we present the consensus that was achieved on these aspects and possible action points from these.

Feeding characteristics of healthy infants without reported feeding impairments throughout the first month of life.

OBJECTIVE: Elucidate characteristics of feeding performance in healthy infants without reported feeding problems throughout the first month of life. STUDY DESIGN: Feeding was monitored in 61 healthy infants by caregiver report for 48 h a week from birth to 4 weeks old. Outcomes included feeding modality, how much they consumed, how long the feed lasted, and how many coughing episodes the infant exhibited. Data were analyzed with descriptive and non-parametric statistics. RESULT: The majority of infants (68%) exhibited at least one problematic feeding behavior. Infants consumed 68 ml/feed over 20 min, though the milk volumes and feed durations were highly variable. Coughing occurred an average of 2 feeds per day. No significant change in coughing was observed throughout the first month of life (p = 0.64). Infants coughed significantly less during breast feeds than bottle feeds (p = 0.02). CONCLUSION: Healthy term infants exhibit what appear to be normal developmental imperfections in feeding performance throughout the first month of life.

Establishing Normative Values for Healthy Term Infant Feeding Performance: Neonatal Eating Assessment Tool-Mixed, Oral Feeding Scale, and Early Feeding Skills Assessment.

PURPOSE: Infants with perceived feeding problems are frequently referred for assessment of their feeding abilities. However, little is known regarding how healthy nondysphagic infants perform on commonly used assessments, making determination of impairment difficult. The aim of this investigation was to elucidate the characteristics of healthy term infant feeding performance using three commonly employed clinical assessments: Neonatal Eating Assessment Tool-Mixed (NeoEat-Mixed), Oral Feeding Scale, and Early Feeding Skills (EFS). METHOD: In this prospective case-control study, we recruited 30 infants without feeding impairments to undergo video-monitored bottle feeds under their normal feeding conditions. Caregiver perception of infant feeding was evaluated using the NeoEat-Mixed. Milk ingestion was monitored real time using the Oral Feeding Scale for rate of milk transfer and modified proficiency as characterized by the total volume consumed out of the total volume the caregiver provided. Videos were analyzed by two speech pathologists using the EFS assessment. Descriptive statistics were used to characterize performance. RESULTS: Participants underwent feeding monitoring at an average chronological age of 4 ± 2 months. Caregivers primarily reported normal, nonconcerning feeding patterns across all of the NeoEAT-Mixed outcomes. Infants consumed milk at an average rate of transfer of 7 ± 3 ml/min, a modified proficiency of 50 ± 21%, and achieved the highest OFS score of 4 (93%, n = 28). The majority of infants scored the best EFS score (mature-3) as it related to the absence of color changes during the feed (97%, n = 29), although commonly scored in the worst EFS score (immature-1) in their presentation of one or more compelling stress cues (63%, n = 19). CONCLUSION: Establishing healthy term infant normative values for commonly used feeding assessments is critical in accurately distinguishing infants with feeding impairments from those with normal developmental variants.

Exploring Alternative Methods to Reduce Milk Flow Rate From Infant Bottle Systems: Bottle Angle, Milk Volume, and Bottle Ventilation.

PURPOSE: Modifying milk flow rate is a common pediatric dysphagia treatment. Though past investigations have demonstrated how this can be achieved using bottle nipples, little is known about the impact of other bottle modifications. The objective of this investigation is to demonstrate how bottle vent, bottle position, and volume of milk alter bottle pressures and milk flow. METHOD: A Dr. Brown's bottle filled with formula was secured to a retort stand and inverted to allow milk to free flow from a Level 1 nipple. Milk flow rate and bottle pressures were calculated under three conditions: (a) with and without a vent in place; (b) with varying volumes of milk (1-4 oz); and (c) in horizontal, semi-inverted, and completely inverted positions. Differences between flow rates under the conditions were tested using repeated-measures analysis of variance. RESULTS: Upon inversion, milk dripped from both vented and unvented bottles. Dripping continued throughout the 20-min testing period in the vented bottle; however, as air pressure and hydrostatic pressure declined (p < .01) in the unvented bottle, milk flow slowed and eventually ceased (p < .001). As angle of bottle inversion increased, hydrostatic pressure and milk flow rate had corresponding increases as well (p < .001). Hydrostatic pressure increased an average of 1.4 ± 0.12 mm Hg per additional ounce of formula that was added to the bottle, with corresponding increases in milk flow rate observed (p < .001). CONCLUSIONS: Milk flow rate can be altered by feeding conditions outside of bottle nipples alone. Future work examining the clinical significance of these modifications is warranted to determine optimal interventions.

Onasemnogene abeparvovec preserves bulbar function in infants with presymptomatic spinal muscular atrophy: a post-hoc analysis of the SPR1NT trial.

Bulbar function in spinal muscular atrophy has been defined as the ability to meet nutritional needs by mouth while maintaining airway protection and communicate verbally. The effects of disease-modifying treatment on bulbar function are not clear. A multidisciplinary team conducted post-hoc analyses of phase 3 SPR1NT trial data to evaluate bulbar function of infants at risk for spinal muscular atrophy who received one-time gene replacement therapy (onasemnogene abeparvovec) before symptom onset. Three endpoints represented adequate bulbar function in SPR1NT: (1) absence of physiologic swallowing impairment, (2) full oral nutrition, and (3) absence of adverse events indicating pulmonary instability. Communication was not assessed in SPR1NT. We descriptively assessed numbers/percentages of children who achieved each endpoint and all three collectively. SPR1NT included infants <6 postnatal weeks with two (n = 14) or three (n = 15) copies of the survival motor neuron 2 gene. At study end (18 [two-copy cohort] or 24 [three-copy cohort] months of age), 100% (29/29) of patients swallowed normally, achieved full oral nutrition, maintained pulmonary stability, and achieved the composite endpoint. When administered to infants before clinical symptom onset, onasemnogene abeparvovec allowed children at risk for spinal muscular atrophy to achieve milestones within published normal ranges of development and preserve bulbar function.

Development of an International SMA Bulbar Assessment for Inter-professional Administration.

BACKGROUND: Progressive weakness can affect bulbar muscles in individuals with moderate to severe forms of spinal muscular atrophy (SMA). The paucity of standardized, valid bulbar assessments capturing clinically significant deficits in SMA impedes the ability to monitor function, facilitate intervention, or detect treatment response. OBJECTIVE: To fill this void, an international multidisciplinary team gathered to develop an agreed upon consensus-derived assessment of bulbar function in SMA for inter-professional administration to enhance our ability to monitor disease progression, support clinical management, and evaluate treatment effects. METHODS: Fifty-six international clinicians experienced in SMA were invited and engaged using the Delphi method over multiple rounds of web-based surveys to establish consensus. RESULTS: Serial virtual meetings occurred with 42 clinicians (21 speech and language therapists, 11 physical therapists, 5 neurologists, 4 occupational therapists, and 1 dentist). Seventy-two validated assessments of bulbar function were identified for potential relevance to individuals with SMA (32 accessible objective, 11 inaccessible objective, 29 patient-reported outcomes). Delphi survey rounds (n = 11, 15, 15) achieved consensus on individual items with relevance and wording discussed. Key aspects of bulbar function identified included: oral intake status, oral facial structure and motor strength, swallowing physiology, voice & speech, and fatigability. CONCLUSIONS: Multidisciplinary clinicians with expertise in bulbar function and SMA used Delphi methodology to reach consensus on assessments/items considered relevant for SMA across all age groups. Future steps include piloting the new scale moving towards validation/reliability. This work supports the advancement of assessing bulbar function in children and adults with SMA by a variety of professionals.

Patients with Spinal Muscular Atrophy Type 1 Achieve and Maintain Bulbar Function Following Onasemnogene Abeparvovec Treatment.

BACKGROUND: Improvement and maintenance of bulbar function are goals of disease-modifying treatments for spinal muscular atrophy (SMA). Lack of standardized measures and a widely accepted definition of bulbar function represents a gap in SMA care. OBJECTIVE: A multidisciplinary team conducted post-hoc analyses of pooled data from one phase 1 (START) and two phase 3 (STR1VE-US, STR1VE-EU) studies to define and evaluate bulbar function of infants with SMA type 1 after receiving one-time gene replacement therapy, onasemnogene abeparvovec. METHODS: We defined bulbar function as the ability to meet nutritional needs while maintaining airway protection and the ability to communicate verbally. Four endpoints represented adequate bulbar function: (1) absence of clinician-identified physiologic swallowing impairment, (2) receiving full oral nutrition, (3) absence of adverse events indicating pulmonary instability, and (4) the ability to vocalize at least two different, distinct vowel sounds. We descriptively assessed numbers/percentages of patients who achieved each endpoint and all four collectively. Patients were followed until 18 months old (STR1VE-US and STR1VE-EU) or 24 months (START) post-infusion. RESULTS: Overall, 65 patients were analyzed for swallowing, nutrition intake, and adverse events, and 20 were analyzed for communication. At study end, 92% (60/65) of patients had a normal swallow, 75% (49/65) achieved full oral nutrition, 92% (60/65) had no evidence of pulmonary instability, 95% (19/20) met the communication endpoint, and 75% (15/20) achieved all four bulbar function components in the composite endpoint. CONCLUSIONS: In these three clinical trials, patients with SMA type 1 who received onasemnogene abeparvovec achieved and maintained the bulbar function criteria utilized within this investigation.

Assessing Bulbar Function in Spinal Muscular Atrophy Using Patient-Reported Outcomes.

BACKGROUND: Novel Spinal Muscular Atrophy (SMA) treatments have demonstrated improvements on motor measures that are clearly distinct from the natural history of progressive decline. Comparable measures are needed to monitor bulbar function, which is affected in severe SMA. OBJECTIVE: To assess bulbar function with patient-reported outcome measures (PROs) and determine their relationships with clinical characteristics. METHODS: We recruited 47 non-ambulatory participants (mean (SD) age = 29.8 (13.7) years, range = 10.3-73.2) with SMA. PROs including Voice Handicap Index (VHI) and Eating Assessment Tool-10 (EAT-10) were collected alongside clinical characteristics and standardized motor assessments. Associations were assessed using Spearman correlation coefficients and group comparisons were performed using Wilcoxon rank sum tests. RESULTS: A majority of the 47 participants were SMA type 2 (70.2%), non-sitters (78.7%), 3 copies of SMN2 (77.5%), and using respiratory support (66.0%). A majority (94%) reported voice issues primarily in 8/30 VHI questions. Problems included: difficulty understanding me in a noisy room (87.2%); difficult for people to hear me (74.5%); and people ask me to repeat when speaking face-to-face (72.3%). A majority (85.1%) reported swallowing issues primarily in 3/10 EAT-10 questions: swallowing pills (68.1%); food sticks to my throat (66.0%); and swallowing solids (61.7%). The two PROs were moderately associated (rs = 0.66). CONCLUSIONS: Weaker individuals with SMA experience bulbar problems including difficulties with voice and swallowing. Further refinement and assessment of functional bulbar scales will help determine their relevance and responsiveness to changes in SMA. Additional study is needed to quantify bulbar changes caused by SMA and their response to disease-modifying treatments.

Dysphagia Phenotypes in Spinal Muscular Atrophy: The Past, Present, and Promise for the Future.

Purpose The aim of this study was to provide clinicians with an overview of literature relating to dysphagia in spinal muscular atrophy (SMA) to guide assessment and treatment. Method In this clinical focus article, we review literature published in Scopus and PubMed between 1990 and 2020 pertaining to dysphagia in SMA across the life span. Original research articles that were published in English were included. Searches were conducted within four themes of inquiry: (a) etiology and phenotypes, (b) respiratory systemic deficits and management, (c) characteristics of natural history dysphagia and its treatment, and (d) dysphagia outcomes with disease-modifying therapies. Articles for the first two themes were selected by content experts who identified the most salient articles that would provide clinicians foundational background knowledge about SMA. Articles for the third theme were identified using search terms, including spinal muscular atrophy, swallow, dysphagia, bulbar, nutrition, g-tube, alternative nutrition, jaw, mouth, palate, OR mandible. Search terms for the fourth theme included spinal muscular atrophy AND nusinersen OR AVXS-101/onasemnogene abeparvovec-xioi. Review of Pertinent Literature Twenty-nine articles were identified. Findings across identified articles support the fact that patients with SMA who do not receive disease-modifying therapy exhibit clinically significant deficits in oropharyngeal swallow function. Few investigations provided systematic information regarding the underlying physiological deficits responsible for this loss in function, the timing of the degradation, or how disease-modifying therapies change these outcomes. Conclusion Future research outlining the physiological and functional oropharyngeal swallowing deficits among patients with SMA who receive disease-modifying therapy is critical in developing standards of dysphagia care to guide clinicians.

Effect of a standardized fluoroscopic procedural approach on fluoroscopy time during infant modified barium swallow studies.

BACKGROUND: Pediatric dysphagia is a term used to describe dysfunctional feeding and swallowing in infants and children. It is estimated that about 1% of children in the United States are affected by these swallowing problems annually. The modified barium swallow study (MBSS) is considered by many as the gold standard in oropharyngeal swallowing assessment. Despite its diagnostic benefits, MBSS exposes infants to ionizing radiation, which carries potentially deleterious long-term effects for the pediatric population. OBJECTIVES: Test the effect of a standardized MBSS procedural protocol on fluoroscopy time when compared to a non-standardized procedural approach. MATERIALS AND METHODS: A retrospective review of infants ≤12 months who underwent a MBSS between 2011 and 2017 was conducted. Charts were reviewed for fluoroscopy time, age, primary diagnosis, MBSS indication, and severity of swallowing deficits. Infants were categorized as non-protocol or standardized protocol based on the utilized method of videofluoroscopic swallow study execution. RESULTS: A total of 1378 MBSS' were included in the analysis. Swallow studies conducted using the standardized procedural protocol had significantly shorter fluoroscopy times (1.5 min) when compared to non-protocol group (2.0 min) (p < 0.001). Patients who aspirated had significantly longer fluoroscopy times when compared to patients who did not aspirate across both groups (p < 0.001). CONCLUSION: Fluoroscopy time is influenced by both procedural and patient factors. Use of a standardized fluoroscopic procedural protocol appears to reduce fluoroscopy time and variability across patients.

Respiratory-Swallow Training Methods: Accuracy of Automated Detection of Swallow Onset, Respiratory Phase, Lung Volume at Swallow Onset, and Real-Time Performance Feedback Tested in Healthy Adults.

Background Preliminary studies have shown that respiratory-swallow training (RST) is a successful treatment for oropharyngeal head and neck cancer patients with refractory dysphagia. Refining the RST protocol with automated analysis software to provide real-time performance feedback has the potential to improve accessibility, reproducibility, and translation to diverse clinical settings. Method An automated software program for data acquisition and analysis developed to detect swallows, determine respiratory phase, calculate lung volume at the onset of the swallow, and provide real-time performance feedback was tested for feasibility in a small cohort of healthy adults. Outcome Measures Percent difference in swallow detection and accuracy of real-time performance feedback of respiratory phase and lung volume at swallowing onset between the automated software and the manual gold standard method were determined. Results The automated software program accurately detected the onset of the swallow on 91% of the swallows completed during the training trials. Feedback of respiratory phase and lung volume was accurate on 94% of the trials in which the swallow was accurately detected. Conclusions This novel, automated, and real-time RST software successfully detected the onset of the swallow, respiratory phase, and lung volume at swallow onset and provided appropriate real-time performance feedback with a high degree of accuracy in healthy adults. The software has the potential to improve the accessibility, efficiency, and translation of RST to diverse patient populations.

The effect of preterm birth, recurrent laryngeal nerve lesion, and postnatal maturation on hyoid and thyroid movements, and their coordination in infant feeding.

Movements of the hyoid and thyroid are critical for feeding. These structures are often assumed to move in synchrony, despite evidence that neurologically compromised populations exhibit altered kinematics. Preterm infants are widely considered to be a neurologically compromised population and often experience feeding difficulties, yet measuring performance, and how performance matures in pediatric populations is challenging. Feeding problems are often compounded by complications arising from surgical procedures performed to ensure the survival of preterm infants, such as damage to the recurrent laryngeal nerve (RLN) during patent ductus arteriosus correction surgery. Here, we used a validated infant pig model for infant feeding to test how preterm birth, postnatal maturation, and RLN lesion interact to impact hyoid and thyroid excursion and their coordination. We filmed infant pigs when feeding using videofluorscopy at seven days old (1-2 months human equivalent) and 17 days old (6-9 months human equivalent) and tracked movements of the hyoid and thyroid on both days. We found that preterm birth impacted the coordination between hyoid and thyroid movements, but not their actual excursion. In contrast, excursion of the two structures increased with postnatal age in term and preterm pigs. RLN lesion decreased thyroid excursion, and primarily impacted hyoid movements by increasing variation in hyoid excursion. This work demonstrates that RLN lesion and preterm birth have distinct, but pervasive effects on feeding performance in infants, and suggest that interventions targeted towards reducing dysphagia should be prescribed based off the etiology driving dysphagia, rather than the prognosis of dysphagia.

Capturing infant swallow impairment on videofluoroscopy: timing matters.

BACKGROUND: Infant videofluoroscopic swallow studies (VFSSs) require clinicians to make determinations about swallowing deficits based on a limited number of fluoroscopically observed swallows. Although airway protection is known to decline throughout a bottle-feed, the paucity of data regarding the timing of this degradation has limited the development of procedural protocols that maximize diagnostic validity. OBJECTIVE: We tested the stability of key components of swallow physiology and airway protection at four standardized timepoints throughout the VFSS. MATERIALS AND METHODS: Thirty bottle-fed infants with clinical signs of swallow dysfunction underwent VFSS. Fluoroscopy was turned on to allow visualization of five swallows at 0:00, 0:30, 1:30 and 2:30 (minutes:seconds [min:s]). We evaluated swallows for components of swallow physiology (oral bolus hold, initiation of pharyngeal swallow, timing of swallow initiation) and airway protection (penetration, aspiration). We used model-based linear contrasts to test differences in the percentage of swallows with low function component attributes. RESULTS: All components of swallow physiology exhibited a change throughout the VFSS (P≤0.0005). Changes were characterized by an increase in the number of sucks per swallow (P<0.0001), percentage of swallows with incomplete bolus hold (P=0.0005), delayed initiation of pharyngeal swallow (P<0.0001), delayed timing of swallow initiation (P=0.0004) and bolus airway entry (P<0.0001). These findings demonstrate that infants with dysphagia exhibit a change in swallow physiology throughout the videofluoroscopic swallow exam. CONCLUSION: Fluoroscopic visualization that is confined to the initial swallows of the bottle feed limit the exam's diagnostic validity. Developing evidence-based procedural guidelines for infant VFSS execution is crucial for maximizing the exam's diagnostic and treatment yield.

First Steps Towards Development of an Instrument for the Reproducible Quantification of Oropharyngeal Swallow Physiology in Bottle-Fed Children.

The incidence of feeding/swallowing impairments (deglutition disorders) in young children is rising and poses serious acute and long-term health consequences. Accurate detection and prompt intervention can lessen the impact of dysphagia-induced sequelae. Videofluoroscopic Swallow Studies (VFSSs) are used to make critical decisions for medically fragile children despite procedural variability and the lack of agreed upon measures for interpreting and reporting results. This investigation represents the first steps in the development of a novel tool for the quantification of oropharyngeal swallow physiology from full-length VFSS examinations in bottle-fed children. The Modified Barium Swallow Impairment Profile MBSImP™© served as the conceptual assessment model for development of components and operational score variants to characterize distinguishable VFSS observations. Twenty-four components of swallowing physiology were validated via expert consensus. Training materials included a library of 94 digitized video images comprised of distinct score variants for each component. Materials were disseminated to seven speech-language pathologists (SLPs) who participated in didactic and self-training sessions, and rated components. All SLPs achieved ≥80% reliability criterion after completing two or three training sessions. Agreement for 17 (71%) components was achieved after two sessions. Nutritive sucking/oral and airway-related components were most difficult to distinguish. Three sessions were required for 2 (33%) of the sucking/oral components and 4 (57%) of the airway-related components. These findings support the feasibility to standardize training and reliably score swallowing physiology using precise definitions and unambiguous visual images, and represent preliminary steps towards content validity and reliability of a standardized VFSS tool for bottle-fed children.

Effect of Single-Use, Laser-Cut, Slow-Flow Nipples on Respiration and Milk Ingestion in Preterm Infants.

PURPOSE: Single-use, laser-cut, slow-flow nipples were evaluated for their effect on respiration and milk ingestion in 13 healthy preterm infants (32.7-37.1 weeks postmenstrual age) under nonlaboratory, clinical conditions. METHOD: The primary outcomes of minute ventilation and overall milk transfer were measured by using integrated nasal airflow and volume-calibrated bottles during suck bursts and suck burst breaks during slow-flow and standard-flow nipple bottle feedings. Wilcoxon signed-ranks tests were used to test the effect of nipple type on both outcomes. RESULTS: Prefeeding minute ventilation decreased significantly during suck bursts and returned to baseline values during suck burst breaks across both slow-flow and standard-flow nipples. No differences were found in minute ventilation (p > .40) or overall milk transfer (p = .58) between slow-flow and standard-flow nipples. CONCLUSIONS: The lack of difference in primary outcomes between the single-use slow-flow and standard-flow nipples may reflect variability in nipple properties among nipples produced by the same manufacturer. Future investigations examining the effect of both single-use and reusable nipple products are warranted to better guide nipple selection during clinical care.

Dysphagia in infants with single ventricle anatomy following stage 1 palliation: Physiologic correlates and response to treatment.

BACKGROUND: Deficits in swallowing physiology are a leading morbidity for infants with functional single ventricles and systemic outflow tract obstruction following stage 1 palliation. Despite the high prevalence of this condition, the underlying deficits that cause this post-operative impairment remain poorly understood. OBJECTIVE: Identify the physiologic correlates of dysphagia in infants with functional single ventricles and systemic outflow tract obstruction following stage 1 palliative surgery. METHODS: Postoperative fiberoptic laryngoscopies and videofluoroscopic swallow studies (VFSS) were conducted sequentially on infants with functional single ventricles following stage 1 palliative surgery. Infants were dichotomized as having normal or impaired laryngeal function based on laryngoscopy findings. VFSS were evaluated frame-by-frame using a scale that quantifies performance within 11 components of swallowing physiology. Physiologic attributes within each component were categorized as high functioning or low functioning based on their ability to support milk ingestion without bolus airway entry. RESULTS: Thirty-six infants (25 male) were included in the investigation. Twenty-four underwent the Norwood procedure and twelve underwent the Hybrid procedure. Low function physiologic patterns were observed within multiple swallowing components during the ingestion of thin barium as characterized by ≥4 sucks per swallow (36%), initiation of pharyngeal swallow below the level of the valleculae (83%), and incomplete late laryngeal vestibular closure (56%) at the height of the swallow. Swallowing deficits contributed to aspiration in 50% of infants. Although nectar thick liquids reduced the rate of aspiration (P = .006), aspiration rates remained high (27%). No differences in rates of penetration or aspiration were observed between infants with normal and impaired laryngeal function. CONCLUSIONS: Deficits in swallowing physiology contribute to penetration and aspiration following stage 1 palliation among infants with normal and impaired laryngeal function. Although thickened liquids may improve airway protection for select infants, they may inhibit their ability to extract the bolus and meet nutritional needs.

Efficacy of Six Tasks to Clear Laryngeal Mucus Aggregation.

PURPOSE: Clinicians commonly teach patients alternative clearing behaviors to reduce coughing and hard throat clearing with the assumption that these behaviors clear mucus from the vocal folds. Yet there is limited evidence of the effectiveness of these alternative behaviors at clearing mucus. This study's purpose was to evaluate the efficacy of reducing laryngeal mucus aggregation using alternative approaches in comparison with hard coughing and hard throat clearing in people with and without voice disorders. METHOD: Mucus aggregation of 46 participants, 22 with and 24 without voice disorders, was evaluated from stroboscopy recordings taken before and after each of six clearing behaviors: hard coughing, hard throat clearing, silent coughing, soft throat clearing, dry swallowing, and swallowing with a fluid bolus. Each participant performed each clearing behavior twice. Two trained raters evaluated mucus aggregation for type, thickness, and pooling. RESULTS: Of the six clearing behaviors studied, only hard throat clearing changed vocal fold mucus aggregation. The features of mucus aggregation that were changed by hard throat clearing were the severity of mucus thickness and the presence of type 3 mucus. CONCLUSIONS: Despite the widespread clinical use of alternative clearing behaviors, the results of this study indicate that hard throat clearing is the only clearing behavior to have a significant impact on removing mucus aggregation from the vocal folds. This finding should be further investigated in a larger scale study. If the results of this study are replicated, clinicians should consider changing their use and description of alternative clearing behaviors in clinical practice.

The physiologic coupling of sucking and swallowing coordination provides a unique process for neonatal survival.

AIM: Although the coordination of sucking and swallowing is critical for successful oral intake in neonates, the mechanisms that facilitate this coordination are not well understood. This investigation sought to clarify the mechanisms that facilitate this coordination, by comparing sucks that were coordinated with swallows and sucks that were completed in isolation. METHODS: Ten neonates with a median gestational age of 28.2 weeks, ranging from 27.0 to 35.0 weeks, were recruited from the neonatal nurseries at Nationwide Children's Hospital, Columbus, Ohio, USA. They were evaluated while bottle-feeding at term gestation for differences in characteristics between sucks that were coupled and not coupled with swallows. Suction was evaluated using an intra-oral pressure transducer, and swallows were identified using a micromanometry pharyngeal catheter. Linear mixed models were applied to distinguish sucking characteristics. RESULTS: Suction exhibited an antiphase relationship with the generation and release of positive pharyngeal pressure during the swallow. Coupled sucks had lower suction generation and release rates (p < 0.0001), lower suction amplitude (p = 0.004), longer suction duration (p < 0.0001) and higher milk ejection pressure (p < 0.0001). CONCLUSION: The coordination of unique sucking and swallowing movement patterns may be achieved by the infant adapting sucking kinematics around the lingual patterns that facilitate the pharyngeal swallow.