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Steer KE, Johnson ML, Edmonds CE, Adjerid K, Bond LE, German RZ, Mayerl CJ. The Impact of Varying Nipple Properties on Infant Feeding Physiology and Performance Throughout Ontogeny in a Validated Animal Model. Dysphagia 2024; 39:460-467. [PMID: 37947879 PMCID: PMC11181904 DOI: 10.1007/s00455-023-10630-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 10/11/2023] [Indexed: 11/12/2023]
Abstract
Infant feeding requires successful interactions between infant physiology and the maternal (or bottle) nipple. Within artificial nipples, there is variation in both nipple stiffness and flow rates, as well as variation in infant physiology as they grow and mature. However, we have little understanding into how infants interact with variable nipple properties to generate suction and successfully feed. We designed nipples with two different stiffnesses and hole sizes and measured infant feeding performance through ontogeny using a pig model. We evaluated their response to nipple properties using high-speed X-Ray videofluoroscopy. Nipple properties substantially impacted sucking physiology and performance. Hole size had the most profound impact on the number of sucks infants took per swallow. Pressure generation generally increased with age, especially in nipples where milk acquisition was more difficult. However, most strikingly, in nipples with lower flow rates the relationship between suction generation and milk acquisition was disrupted. In order to design effective interventions for infants with feeding difficulties, we must consider how variation in nipple properties impacts infant physiology in a targeted manner. While reducing flow rate may reduce the frequency an infant aspirates, it may impair systems involved in sensorimotor integration.
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Affiliation(s)
- K E Steer
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, 4209 St Route 44, Rootstown, OH, 44272, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, USA
| | - M L Johnson
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, 4209 St Route 44, Rootstown, OH, 44272, USA
| | - C E Edmonds
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, 4209 St Route 44, Rootstown, OH, 44272, USA
- School of Biomedical Sciences, Kent State University, Kent, USA
| | - K Adjerid
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, 4209 St Route 44, Rootstown, OH, 44272, USA
- Department of Biomedical Engineering, Tulane University, New Orleans, USA
| | - L E Bond
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, 4209 St Route 44, Rootstown, OH, 44272, USA
| | - R Z German
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, 4209 St Route 44, Rootstown, OH, 44272, USA
| | - C J Mayerl
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, 4209 St Route 44, Rootstown, OH, 44272, USA.
- Department of Biological Sciences, Northern Arizona University, Flagstaff, USA.
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Ross CF, Laurence-Chasen JD, Li P, Orsbon C, Hatsopoulos NG. Biomechanical and Cortical Control of Tongue Movements During Chewing and Swallowing. Dysphagia 2024; 39:1-32. [PMID: 37326668 PMCID: PMC10781858 DOI: 10.1007/s00455-023-10596-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 05/23/2023] [Indexed: 06/17/2023]
Abstract
Tongue function is vital for chewing and swallowing and lingual dysfunction is often associated with dysphagia. Better treatment of dysphagia depends on a better understanding of hyolingual morphology, biomechanics, and neural control in humans and animal models. Recent research has revealed significant variation among animal models in morphology of the hyoid chain and suprahyoid muscles which may be associated with variation in swallowing mechanisms. The recent deployment of XROMM (X-ray Reconstruction of Moving Morphology) to quantify 3D hyolingual kinematics has revealed new details on flexion and roll of the tongue during chewing in animal models, movements similar to those used by humans. XROMM-based studies of swallowing in macaques have falsified traditional hypotheses of mechanisms of tongue base retraction during swallowing, and literature review suggests that other animal models may employ a diversity of mechanisms of tongue base retraction. There is variation among animal models in distribution of hyolingual proprioceptors but how that might be related to lingual mechanics is unknown. In macaque monkeys, tongue kinematics-shape and movement-are strongly encoded in neural activity in orofacial primary motor cortex, giving optimism for development of brain-machine interfaces for assisting recovery of lingual function after stroke. However, more research on hyolingual biomechanics and control is needed for technologies interfacing the nervous system with the hyolingual apparatus to become a reality.
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Affiliation(s)
- Callum F Ross
- Department of Organismal Biology & Anatomy, The University of Chicago, 1027 East 57th St, Chicago, IL, 60637, USA.
| | - J D Laurence-Chasen
- National Renewable Energy Laboratory, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Peishu Li
- Department of Organismal Biology & Anatomy, The University of Chicago, 1027 East 57th St, Chicago, IL, 60637, USA
| | - Courtney Orsbon
- Department of Radiology, University of Vermont Medical Center, Burlington, USA
| | - Nicholas G Hatsopoulos
- Department of Organismal Biology & Anatomy, The University of Chicago, 1027 East 57th St, Chicago, IL, 60637, USA
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Li P, Ross CF, Luo ZX, Gidmark NJ. Head posture impacts mammalian hyoid position and suprahyoid muscle length: implication for swallowing biomechanics. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220552. [PMID: 37839446 PMCID: PMC10577029 DOI: 10.1098/rstb.2022.0552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 08/05/2023] [Indexed: 10/17/2023] Open
Abstract
Instantaneous head posture (IHP) can extensively alter resting hyoid position in humans, yet postural effects on resting hyoid position remain poorly documented among mammals in general. Clarifying this relationship is essential for evaluating interspecific variation in hyoid posture across evolution, and understanding its implications for hyolingual soft tissue function and swallowing motor control. Using Didelphis virginiana as a model, we conducted static manipulation experiments to show that head flexion shifts hyoid position rostrally relative to the cranium across different gapes. IHP-induced shifts in hyoid position along the anteroposterior axis are comparable to in vivo hyoid protraction distance during swallowing. IHP also has opposite effects on passive genio- and stylohyoid muscle lengths. High-speed biplanar videoradiography suggests Didelphis consistently swallows at neutral to flexed posture, with stereotyped hyoid kinematics across different head postures. IHP change can affect suprahyoid muscle force production by shifting their positions on the length-tension curve, and redirecting lines of action and the resultant force from supra- and infrahyoid muscles. We hypothesize that demands on muscle performance may constrain the range of swallowing head postures in mammals. This article is part of the theme issue 'Food processing and nutritional assimilation in animals'.
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Affiliation(s)
- Peishu Li
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago IL, 60637, USA
| | - Callum F. Ross
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago IL, 60637, USA
| | - Zhe-Xi Luo
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago IL, 60637, USA
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Mayerl CJ, German RZ. Evolution, diversification and function of the maternal-infant dyad in mammalian feeding. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220554. [PMID: 37839443 PMCID: PMC10577036 DOI: 10.1098/rstb.2022.0554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Accepted: 08/17/2023] [Indexed: 10/17/2023] Open
Abstract
The evolution of the mother/infant dyad providing a source of nutrition for infants is essential for the origin and subsequent diversification of mammals. Despite the importance of this dyad, research on maternal and infant function is often treated independently. Our goal is to synthesize the work on maternal and infant function, discuss our own studies of suckling, and compare the origins of lactation and suckling with their ensuing diversification. Our central premise is that while extensive work has demonstrated variation across mammals in the maternal aspect of this system, very little has been done to address how this relates to infant function. We start with a discussion of the fundamental anatomy and physiology of both mother and infant. We next discuss the origin of mammary glands and milk, and infant suckling, which is distinct from their subsequent diversification. We then discuss the diversification of maternal and infant function, highlighting the evolutionary diversity present in maternal function (both anatomically and physiologically), before arguing that the diversity of infant function is unexplored, and needs to be better studied in the future. We end by discussing some of the holes in our understanding, and suggestions for future work that can address these lacunae. This article is part of the theme issue 'Food processing and nutritional assimilation in animals'.
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Affiliation(s)
- Christopher J. Mayerl
- Department of Anatomy & Neurobiology, Northeast Ohio Medical University, Rootstown, OH 44272, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86001-5766, USA
| | - Rebecca Z. German
- Department of Anatomy & Neurobiology, Northeast Ohio Medical University, Rootstown, OH 44272, USA
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Johnson ML, Steer KE, Edmonds CE, Adjerid K, German RZ, Mayerl CJ. Nipple properties affect sensorimotor integration during bottle feeding in an infant pig model. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2023; 339:767-776. [PMID: 37438924 PMCID: PMC10528713 DOI: 10.1002/jez.2727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 06/13/2023] [Accepted: 06/16/2023] [Indexed: 07/14/2023]
Abstract
Infant feeding is a critical neurological milestone in development defined by the coordination of muscles, peripheral nerves, and brainstem nuclei. In infants, milk flow rate is often limited to improve feeding performance without treating the underlying deficiencies in the sucking and swallowing processes. Modification of the neuromotor response via sensory information from the nipple during bottle feeding is an unexplored avenue for physiology-based interventions. In this study, we assessed how differences in nipple hole size and nipple stiffness affect sucking muscle activation and subsequent movement. We fabricated four bottle nipples of varying hole size and stiffness to determine how variation in nipple properties affects the sucking behavior of infant pigs. Our results demonstrate that sensory information from the nipple affects sucking motor output. Nipple hole sizes and stiffnesses with a larger milk flow rate resulted in greater muscle activity and kinematic movement. Additionally, our results suggest that sensorimotor interventions are better directed toward modulating tongue function rather than the mandible movements due to a greater response to sensory information. Understanding how sensory information influences infant feeding is instrumental in promoting effective infant feeding.
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Affiliation(s)
- ML Johnson
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH
| | - KE Steer
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ
| | - CE Edmonds
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH
| | - K Adjerid
- Department of Biomedical Engineering, Tulane University, New Orleans, LA
| | - RZ German
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH
| | - CJ Mayerl
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ
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6
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Steer KE, Johnson ML, Adjerid K, Bond LE, Howe SP, Khalif A, Nkachukwu KC, Edmonds CE, German RZ, Mayerl CJ. The Function of the Mammal Extrinsic Tongue Musculature in the Transition from Suckling to Drinking. Integr Comp Biol 2023; 63:641-652. [PMID: 37160353 PMCID: PMC10503468 DOI: 10.1093/icb/icad023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 04/25/2023] [Accepted: 05/02/2023] [Indexed: 05/11/2023] Open
Abstract
The transition from suckling to drinking is a developmental pathway that all mammals take. In both behaviors, the tongue is the primary structure involved in acquiring, transporting, and swallowing the liquid. However, the two processes are fundamentally different: during suckling, the tongue must function as a pump to generate suction to move milk, whereas during drinking, the tongue moves backwards and forwards through the mouth to acquire and move water. Despite these fundamental differences, we have little understanding of how tongues role varies between these behaviors. We used an infant pig model to investigate the relationships between anatomy, physiology, and function of the tongue to examine how lingual function is modulated in the transition from infancy to adulthood. We found that while some muscles were proportionally largest at birth, others were proportionally larger at the time of weaning. Furthermore, we found variation in tongue movements between suckling and drinking along both the mediolateral and anteroposterior axes, resulting in differences in tongue deformation between the two behaviors. The extrinsic tongue muscles also changed in function differently between drinking and suckling. Genioglossus increased its activity and turned on and off earlier in the cycle during drinking, whereas hyoglossus fired at lower amplitudes during drinking, and turned on and off later in the cycle. Together, the data highlight the significant need for high neuroplasticity in the control of the tongue at a young age in mammals and suggest that the ability to do so is key in the ontogeny and evolution of feeding in these animals.
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Affiliation(s)
- K E Steer
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown OH 44272, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - M L Johnson
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown OH 44272, USA
| | - K Adjerid
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown OH 44272, USA
- Department of Biomedical Engineering, Tulane University, New Orleans, Lousiana, 70118, USA
| | - L E Bond
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown OH 44272, USA
| | - S P Howe
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown OH 44272, USA
| | - A Khalif
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown OH 44272, USA
| | - K C Nkachukwu
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown OH 44272, USA
| | - C E Edmonds
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown OH 44272, USA
- School of Biomedical Sciences, Kent State University, Kent, OH 44242, USA
| | - R Z German
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown OH 44272, USA
| | - C J Mayerl
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA
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Mayerl CJ, Gould FDH, Adjerid K, Edmonds C, German RZ. The Pathway from Anatomy and Physiology to Diagnosis: A Developmental Perspective on Swallowing and Dysphagia. Dysphagia 2023; 38:33-41. [PMID: 35441265 PMCID: PMC9579268 DOI: 10.1007/s00455-022-10449-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 04/04/2022] [Indexed: 01/29/2023]
Abstract
Dysphagia results from diverse and distinct etiologies. The pathway from anatomy and physiology to clinical diagnosis is complex and hierarchical. Our approach in this paper is to show the linkages from the underlying anatomy and physiology to the clinical presentation. In particular, the terms performance, function, behavior, and physiology are often used interchangeably, which we argue is an obstacle to clear discussion of mechanism of pathophysiology. We use examples from pediatric populations to highlight the importance of understanding anatomy and physiology to inform clinical practice. We first discuss the importance of understanding anatomy in the context of physiology and performance. We then use preterm infants and swallow-breathe coordination as examples to explicate the hierarchical nature of physiology and its impact on performance. We also highlight where the holes in our knowledge lie, with the ultimate endpoint of providing a framework that could enhance our ability to design interventions to help patients. Clarifying these terms, and the roles they play in the biology of dysphagia will help both the researchers studying the problems as well as the clinicians applying the results of those studies.
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Affiliation(s)
- C J Mayerl
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, 44272, USA
| | - F D H Gould
- Department of Cell Biology and Neuroscience, Rowan University School of Osteopathic Medicine, Stratford, NJ, USA
| | - K Adjerid
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, 44272, USA
| | - C Edmonds
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, 44272, USA
| | - R Z German
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, 44272, USA.
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Adjerid K, Johnson M, Edmonds C, Steer K, Gould F, German R, Mayerl C. The effect of stiffness and hole size on nipple compression in infant suckling. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2023; 339:92-100. [PMID: 36121049 PMCID: PMC9771940 DOI: 10.1002/jez.2657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 08/04/2022] [Accepted: 08/24/2022] [Indexed: 12/24/2022]
Abstract
During infant feeding, the nipple is an important source of sensory information that affects motor outputs, including ones dealing with compression of the nipple, suction, milk bolus movement, and swallowing. Despite known differences in behavior across commercially available nipples, little is known about the in vivo effects of nipple property variation. Here we quantify the effect of differences in nipple stiffness and hole size on an easily measured metric representing infant feeding behavior: nipple compression. We bottle-fed 7-day old infant pigs (n = 6) on four custom fabricated silicone nipples. We recorded live X-ray fluoroscopic imaging data of feeding on nipples of two levels of hardness/stiffness and two hole sizes. We tested for differences in nipple compression at the nipple's maximum compression across different nipple types using a mixed model analysis of variance. Stiffer nipples and those with smaller holes were compressed less than compliant nipples and nipples with larger holes (p < 0.001). We also estimated the force applied on the nipple during feeding and found that more force was applied to the compliant nipple with disproportionately larger strains. Our results suggest that infant pigs' nipple compression depends on material type and hole size, which is likely detected by the infant pigs' initial assessment of compressibility and flow. By isolating nipple properties, we demonstrated a relationship between properties and suckling behavior. Our results suggest that sensory information affects feeding behaviors and may also inform clinical treatment of poor feeding performance.
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Affiliation(s)
- K. Adjerid
- Northeast Ohio Medical University, Rootstown, OH
| | - M.L. Johnson
- Northeast Ohio Medical University, Rootstown, OH
| | - C.E. Edmonds
- Northeast Ohio Medical University, Rootstown, OH
| | - K.E. Steer
- Northeast Ohio Medical University, Rootstown, OH
| | - F.D.H. Gould
- Rowan University School of Osteopathic Medicine, Glassboro, NJ
| | - R.Z. German
- Northeast Ohio Medical University, Rootstown, OH
| | - C.J. Mayerl
- Northeast Ohio Medical University, Rootstown, OH
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Mayerl CJ, Adjerid KA, Edmonds CE, Gould FDH, Johnson ML, Steer KE, Bond LE, German RZ. Regional Variation in Contractile Patterns and Muscle Activity in Infant Pig Feeding. Integr Org Biol 2022; 4:obac046. [PMID: 36531210 PMCID: PMC9756950 DOI: 10.1093/iob/obac046] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2023] Open
Abstract
At the level of the whole muscle, contractile patterns during activity are a critical and necessary source of variation in function. Understanding if a muscle is actively lengthening, shorting, or remaining isometric has implications for how it is working to power a given behavior. When feeding, the muscles associated with the tongue, jaws, pharynx, and hyoid act together to transport food through the oral cavity and into the esophagus. These muscles have highly coordinated firing patterns, yet also exhibit high levels of regional heterogeneity in both their timing of activity and their contractile characteristics when active. These high levels of variation make investigations into function challenging, especially in systems where muscles power multiple behaviors. We used infant pigs as a model system to systematically evaluate variation in muscle firing patterns in two muscles (mylohyoid and genioglossus) during two activities (sucking and swallowing). We also evaluated the contractile characteristics of mylohyoid during activity in the anterior and posterior regions of the muscle. We found that the posterior regions of both muscles had different patterns of activity during sucking versus swallowing, whereas the anterior regions of the muscles did not. Furthermore, the anterior portion of mylohyoid exhibited concentric contractions when active during sucking, whereas the posterior portion was isometric during sucking and swallowing. This difference suggests that the anterior portion of mylohyoid in infant pigs is functioning in concert with the tongue and jaws to generate suction, whereas the posterior portion is likely acting as a hyoid stabilizer during sucking and swallowing. Our results demonstrate the need to evaluate both the contractile characteristics and activity patterns of a muscle in order to understand its function, especially in cases where there is potential for variation in either factor within a single muscle.
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Affiliation(s)
- C J Mayerl
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, 44272, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - K A Adjerid
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, 44272, USA
- Department of Biomedical Engineering, Tulane University, New Orleans, LA, 70118, USA
| | - C E Edmonds
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, 44272, USA
| | - F D H Gould
- Rowan University School of Osteopathic Medicine, Stratford, NJ, 08084, USA
| | - M L Johnson
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, 44272, USA
| | - K E Steer
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, 44272, USA
| | - L E Bond
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, 44272, USA
| | - R Z German
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, 44272, USA
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Malandraki GA, Arkenberg RH. Advances in Swallowing Neurophysiology across Pediatric Development: Current Evidence and Insights. CURRENT PHYSICAL MEDICINE AND REHABILITATION REPORTS 2021; 9:267-276. [PMID: 34956736 DOI: 10.1007/s40141-021-00334-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Purpose of Review This review article analyzes current evidence on the neurophysiology of swallowing during development and offers expert opinion on clinical implications and future research directions. Recent Findings In the past five years, basic and clinical research has offered advances in our understanding of pediatric swallowing neurophysiology. Animal models have elucidated the role of brainstem circuits and the peripheral and central nervous system in neonatal swallowing. Recent human studies have further showcased that fetal and infant swallowing require cerebral inputs in order to develop functionally. Finally, neurophysiological and neuroimaging studies are starting to better define these cerebral inputs, as well as neuroplastic adaptations that may be needed for optimal feeding development. Summary The neural development of swallowing is a complex and dynamic process. Continued research is needed to better understand influences on swallowing neural development, which can be essential for improving prevention, diagnosis, and interventions for pediatric dysphagia.
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Affiliation(s)
- Georgia A Malandraki
- Purdue University, Speech, Language, & Hearing Sciences, West Lafayette, Indiana, United States of America
- Purdue University, Weldon School of Biomedical Engineering, West Lafayette, Indiana, United States of America
| | - Rachel Hahn Arkenberg
- Purdue University, Speech, Language, & Hearing Sciences, West Lafayette, Indiana, United States of America
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Mayerl CJ, Steer KE, Chava AM, Bond LE, Edmonds CE, Gould FDH, Hieronymous TL, Vinyard CJ, German RZ. Anatomical and physiological variation of the hyoid musculature during swallowing in infant pigs. J Exp Biol 2021; 224:jeb243075. [PMID: 34734633 PMCID: PMC10659033 DOI: 10.1242/jeb.243075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 10/06/2021] [Indexed: 11/20/2022]
Abstract
The function of a muscle is impacted by its line of action, activity timing and contractile characteristics when active, all of which have the potential to vary within a behavior. One function of the hyoid musculature is to move the hyoid bone during swallowing, yet we have little insight into how their lines of action and contractile characteristics might change during a swallow. We used an infant pig model to quantify the contractile characteristics of four hyoid muscles during a swallow using synchronized electromyography, fluoromicrometry and high-speed biplanar videofluoroscopy. We also estimated muscle line of action during a swallow using contrast-enhanced CT-scanned muscles animated to move with the hyoid bone and found that as the hyoid elevated, the line of action of the muscles attached to it became greater in depression. We also found that muscles acted eccentrically and concentrically, which was correlated with hyoid movement. This work contributes to our understanding of how the musculature powering feeding functions during swallowing.
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Affiliation(s)
- Christopher J. Mayerl
- NEOMED Department of Anatomy and Neurobiology, Northeast Ohio Medical University, 4209 State Route 44, PO Box 95, Rootstown, OH 44272, USA
| | - Kendall E. Steer
- NEOMED Department of Anatomy and Neurobiology, Northeast Ohio Medical University, 4209 State Route 44, PO Box 95, Rootstown, OH 44272, USA
| | - Almasi M. Chava
- NEOMED Department of Anatomy and Neurobiology, Northeast Ohio Medical University, 4209 State Route 44, PO Box 95, Rootstown, OH 44272, USA
| | - Laura E. Bond
- NEOMED Department of Anatomy and Neurobiology, Northeast Ohio Medical University, 4209 State Route 44, PO Box 95, Rootstown, OH 44272, USA
| | - Chloe E. Edmonds
- NEOMED Department of Anatomy and Neurobiology, Northeast Ohio Medical University, 4209 State Route 44, PO Box 95, Rootstown, OH 44272, USA
| | - Francois D. H. Gould
- Department of Cell Biology and Neuroscience, Rowan School of Osteopathic Medicine, Stratford, NJ 08084, USA
| | - Tobin L. Hieronymous
- NEOMED Department of Anatomy and Neurobiology, Northeast Ohio Medical University, 4209 State Route 44, PO Box 95, Rootstown, OH 44272, USA
| | - Christopher J. Vinyard
- NEOMED Department of Anatomy and Neurobiology, Northeast Ohio Medical University, 4209 State Route 44, PO Box 95, Rootstown, OH 44272, USA
| | - Rebecca Z. German
- NEOMED Department of Anatomy and Neurobiology, Northeast Ohio Medical University, 4209 State Route 44, PO Box 95, Rootstown, OH 44272, USA
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12
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Mayerl CJ, Edmonds CE, Gould FDH, German RZ. Increased viscosity of milk during infant feeding improves swallow safety through modifying sucking in an animal model. J Texture Stud 2021; 52:603-611. [PMID: 33783823 DOI: 10.1111/jtxs.12599] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 02/17/2021] [Accepted: 03/25/2021] [Indexed: 11/28/2022]
Abstract
Infants experiencing frequent aspiration, the entry of milk into the airway, are often prescribed thickened fluids to improve swallow safety. However, research on the outcomes of thickened milk on infant feeding have been limited to documenting rates of aspiration and the rheologic properties of milk following thickening. As a result, we have little insight into the physiologic and behavioral mechanisms driving differences in performance during feeding on high viscosity milk. Understanding the physiologic and behavioral mechanisms driving variation in performance at different viscosities is especially critical, because the structures involved in feeding respond differently to sensory stimulation. We used infant pigs, a validated animal model for infant feeding, to test how the tongue, soft palate, and hyoid respond to changes in viscosity during sucking and swallowing, in addition to measuring swallow safety and bolus size. We found that the tongue exhibited substantive changes in its movements associated with thickened fluids during sucking and swallowing, but that pharyngeal transit time as well as hyoid and soft palate movements during swallowing were unaffected. This work demonstrates the integrated nature of infant feeding and that behaviors associated with sucking are more sensitive to sensorimotor feedback associated with changes in milk viscosity than those associated with the pharyngeal swallow, likely due to its reflexive nature.
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Affiliation(s)
- Christopher J Mayerl
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University (NEOMED), Rootstown, Ohio, USA
| | - Chloe E Edmonds
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University (NEOMED), Rootstown, Ohio, USA
| | - Francois D H Gould
- Department of Cell Biology and Neuroscience, Rowan School of Osteopathic Medicine, Stratford, New Jersey, USA
| | - Rebecca Z German
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University (NEOMED), Rootstown, Ohio, USA
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Mayerl CJ, Steer KE, Chava AM, Bond LE, Edmonds CE, Gould FDH, Stricklen BM, Hieronymous TL, German RZ. The contractile patterns, anatomy and physiology of the hyoid musculature change longitudinally through infancy. Proc Biol Sci 2021; 288:20210052. [PMID: 33715426 DOI: 10.1098/rspb.2021.0052] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
All mammalian infants suckle, a fundamentally different process than drinking in adults. Infant mammal oropharyngeal anatomy is also anteroposteriorly compressed and becomes more elongate postnatally. While suckling and drinking require different patterns of muscle use and kinematics, little insight exists into how the neuromotor and anatomical systems change through the time that infants suckle. We measured the orientation, activity and contractile patterns of five muscles active during infant feeding from early infancy until weaning using a pig model. Muscles not aligned with the long axis of the body became less mediolaterally orientated with age. However, the timing of activation and the contractile patterns of those muscles exhibited little change, although variation was larger in younger infants than older infants. At both ages, there were differences in contractile patterns within muscles active during both sucking and swallowing, as well as variation among muscles during swallowing. The changes in anatomy, coupled with less variation closer to weaning and little change in muscle firing and shortening patterns suggest that the neuromotor system may be optimized to transition to solid foods. The lesser consequences of aspiration during feeding on an all-liquid diet may not necessitate the evolution of variation in neuromotor function through infancy.
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Affiliation(s)
- C J Mayerl
- NEOMED Department of Anatomy and Neurobiology, 4209 State Route 44, PO Box 95, Rootstown OH 44272, USA
| | - K E Steer
- NEOMED Department of Anatomy and Neurobiology, 4209 State Route 44, PO Box 95, Rootstown OH 44272, USA
| | - A M Chava
- NEOMED Department of Anatomy and Neurobiology, 4209 State Route 44, PO Box 95, Rootstown OH 44272, USA
| | - L E Bond
- NEOMED Department of Anatomy and Neurobiology, 4209 State Route 44, PO Box 95, Rootstown OH 44272, USA
| | - C E Edmonds
- NEOMED Department of Anatomy and Neurobiology, 4209 State Route 44, PO Box 95, Rootstown OH 44272, USA
| | - F D H Gould
- Department of Cell Biology and Neuroscience, Rowan School of Osteopathic Medicine, Stratford, NJ, USA
| | - B M Stricklen
- NEOMED Department of Anatomy and Neurobiology, 4209 State Route 44, PO Box 95, Rootstown OH 44272, USA
| | - T L Hieronymous
- NEOMED Department of Anatomy and Neurobiology, 4209 State Route 44, PO Box 95, Rootstown OH 44272, USA
| | - R Z German
- NEOMED Department of Anatomy and Neurobiology, 4209 State Route 44, PO Box 95, Rootstown OH 44272, USA
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Adjerid K, Mayerl CJ, Gould FDH, Edmonds CE, Stricklen BM, Bond LE, German RZ. Does birth weight affect neonatal body weight, growth, and physiology in an animal model? PLoS One 2021; 16:e0246954. [PMID: 33592070 PMCID: PMC7886147 DOI: 10.1371/journal.pone.0246954] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 01/28/2021] [Indexed: 02/03/2023] Open
Abstract
Infant birth weight affects neuromotor and biomechanical swallowing performance in infant pig models. Preterm infants are generally born low birth weight and suffer from delayed development and neuromotor deficits. These deficits include critical life skills such as swallowing and breathing. It is unclear whether these neuromotor and biomechanical deficits are a result of low birth weight or preterm birth. In this study we ask: are preterm infants simply low birth weight infants or do preterm infants differ from term infants in weight gain and swallowing behaviors independent of birth weight? We use a validated infant pig model to show that preterm and term infants gain weight differently and that birth weight is not a strong predictor of functional deficits in preterm infant swallowing. We found that preterm infants gained weight at a faster rate than term infants and with nearly three times the variation. Additionally, we found that the number of sucks per swallow, swallow duration, and the delay of the swallows relative to the suck cycles were not impacted by birth weight. These results suggest that any correlation of developmental or swallowing deficits with reduced birth weight are likely linked to underlying physiological immaturity of the preterm infant.
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Affiliation(s)
- Khaled Adjerid
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, Ohio, United States of America
- * E-mail:
| | - Christopher J. Mayerl
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, Ohio, United States of America
| | - Francois D. H. Gould
- Department of Cell Biology and Neuroscience, Rowan University School of Osteopathic Medicine, Stratford, New Jersey, United States of America
| | - Chloe E. Edmonds
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, Ohio, United States of America
| | - Bethany M. Stricklen
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, Ohio, United States of America
| | - Laura E. Bond
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, Ohio, United States of America
| | - Rebecca Z. German
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, Ohio, United States of America
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Mayerl CJ, Edmonds CE, Catchpole EA, Myrla AM, Gould FDH, Bond LE, Stricklen BM, German RZ. Sucking versus swallowing coordination, integration, and performance in preterm and term infants. J Appl Physiol (1985) 2020; 129:1383-1392. [PMID: 33054658 DOI: 10.1152/japplphysiol.00668.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Mammalian infants must be able to integrate the acquisition, transport, and swallowing of food to effectively feed. Understanding how these processes are coordinated is critical, as they have differences in neural control and sensitivity to perturbation. Despite this, most studies of infant feeding focus on isolated processes, resulting in a limited understanding of the role of sensorimotor integration in the different processes involved in infant feeding. This is especially problematic in the context of preterm infants, as they are considered to have pathophysiological brain development and often experience feeding difficulties. Here, we use an animal model to study how the different properties of food acquisition, transport, and swallowing differ between term and preterm infants longitudinally through infancy to understand which processes are sensitive to variation in the bolus being swallowed. We found that term infants are better able to acquire milk than preterm infants, and that properties of acquisition are strongly correlated with the size of the bolus being swallowed. In contrast, behaviors occurring during the pharyngeal swallow, such as hyoid and soft palate movements, show little to no correlation with bolus size. These results highlight the pathophysiological nature of the preterm brain and also demonstrate that behaviors occurring during oral transport are much more likely to respond to sensory intervention than those occurring during the "pharyngeal phase."NEW & NOTEWORTHY Physiological maturation of infant feeding is clinically and developmentally significant, but seldom examined as an integrated function. Using longitudinal high-speed videofluoroscopic data, we found that properties of sucking, such as the length of the suck, are more sensitive to swallow physiology than those associated with the pharyngeal swallow itself, such as hyoid excursion. Prematurity impacted the function and maturation of the feeding system, resulting in a physiology that fundamentally differs from term infants by weaning.
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Affiliation(s)
- Christopher J Mayerl
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University (NEOMED), Rootstown, Ohio
| | - Chloe E Edmonds
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University (NEOMED), Rootstown, Ohio
| | - Emily A Catchpole
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University (NEOMED), Rootstown, Ohio
| | - Alexis M Myrla
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University (NEOMED), Rootstown, Ohio
| | - Francois D H Gould
- Department of Cell Biology and Neuroscience, Rowan School of Osteopathic Medicine, Stratford, New Jersey
| | - Laura E Bond
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University (NEOMED), Rootstown, Ohio
| | - Bethany M Stricklen
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University (NEOMED), Rootstown, Ohio
| | - Rebecca Z German
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University (NEOMED), Rootstown, Ohio
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Edmonds CE, Catchpole EA, Gould FDH, Bond LE, Stricklen BM, German RZ, Mayerl CJ. Preterm Birth Impacts the Timing and Excursion of Oropharyngeal Structures during Infant Feeding. Integr Org Biol 2020; 2:obaa028. [PMID: 33103058 PMCID: PMC7568519 DOI: 10.1093/iob/obaa028] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Swallowing in mammals requires the precise coordination of multiple oropharyngeal structures, including the palatopharyngeal arch. During a typical swallow, the activity of the palatopharyngeus muscle produces pharyngeal shortening to assist in producing pressure required to swallow and may initiate epiglottal flipping to protect the airway. Most research on the role of the palatopharyngeal arch in swallowing has used pharyngeal manometry, which measures the relative pressures in the oropharynx, but does not quantify the movements of the structures involved in swallowing. In this study, we assessed palatopharyngeal arch and soft palate function by comparing their movements in a healthy population to a pathophysiological population longitudinally through infancy (term versus preterm pigs). In doing so, we test the impact of birth status, postnatal maturation, and their interaction on swallowing. We tracked the three-dimensional (3D) movements of radiopaque beads implanted into relevant anatomical structures and recorded feeding via biplanar high-speed videofluoroscopy. We then calculated the total 3D excursion of the arch and soft palate, the orientation of arch movement, and the timing of maximal arch constriction during each swallow. Soft palate excursion was greater in term infants at both 7 and 17 days postnatal, whereas arch excursion was largely unaffected by birth status. Maximal arch constriction occurred much earlier in preterm pigs relative to term pigs, a result that was consistent across age. There was no effect of postnatal age on arch or soft palate excursion. Preterm and term infants differed in their orientation of arch movement, which most likely reflects both differences in anatomy and differences in feeding posture. Our results suggest that the timing and coordination of oropharyngeal movements may be more important to feeding performance than the movements of isolated structures, and that differences in the neural control of swallowing and its maturation in preterm and term infants may explain preterm swallowing deficits.
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Affiliation(s)
- C E Edmonds
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University (NEOMED), Rootstown, OH 44272, USA
| | - E A Catchpole
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University (NEOMED), Rootstown, OH 44272, USA
| | - F D H Gould
- Department of Cell Biology and Neuroscience, Rowan School of Osteopathic Medicine, Stratford, NJ 08854, USA
| | - L E Bond
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University (NEOMED), Rootstown, OH 44272, USA
| | - B M Stricklen
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University (NEOMED), Rootstown, OH 44272, USA
| | - R Z German
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University (NEOMED), Rootstown, OH 44272, USA
| | - C J Mayerl
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University (NEOMED), Rootstown, OH 44272, USA
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