Teresa Pitts

University of Missouri | Mizzou · Department of Speech, Language, and Hearing Sciences

Swallow is a primitive behavior regulated by medullary networks, responsible for movement of food/liquid from the oral cavity to the esophagus. To investigate how functionally heterogeneous networks along the medullary intermediate reticular formation (IRt) and ventral respiratory column (VRC) control swallow, we electrically stimulated the nucleus...

Laryngeal function is vital to airway protection. While swallow is mediated by the brainstem, mechanisms underlying increased risk of dysphagia after cervical spinal cord injury (SCI) are unknown. We hypothesized that loss of descending phrenic drive affects swallow and breathing differently, and loss of ascending spinal afferent information alters...

Despite centuries of investigation, questions and controversies remain regarding the fundamental genesis and motor pattern of swallow. Two significant topics include inspiratory muscle activity during swallow (Schluckatmung, i.e., "swallow-breath"), and anatomical boundaries of the swallow pattern generator. We discuss the long history of reports r...

Objective Postoperative pneumonia remains a common complication of surgery, despite increased attention. The purpose of our study was to determine the effects of routine surgery and post-surgical opioid administration on airway protection risk. Methods Eight healthy adult cats were evaluated for dysphagia in 2 experiments. 1) In 4 female cats airw...

Introduction Aspiration pneumonia, a leading cause of mortality, poses an urgent challenge in contemporary society. Neuromuscular electrical stimulation (NMES) has been commonly used in dysphagia rehabilitation. However, given that NMES at motor threshold targets only specific muscles, it carries a potential risk of further compromising functions r...

Systemic administration of opioids has been associated with aspiration and swallow dysfunction in humans. We speculated that systemic administration of codeine would induce dysfunctional swallowing and that this effect would have a peripheral component. Experiments were conducted in spontaneously breathing, anesthetized cats. The animals were trach...

The current study aims to determine mechanisms of impaired airway protection following opioid administration. Experiments were performed on N=10 anesthetized male Sprague Dawley rats. Bipolar fine wire electromyogram (EMG) wires were implanted in various muscles to evaluate breathing and swallowing. Swallows were evoked by activation of laryngeal t...

Late Onset Pompe Disease (LOPD) is an incurable, rare progressive genetic disease. It is characterized by glycogen build-up, due to mutations in the gene encoding the lysosomal enzyme acid alpha glucosidase, throughout muscle and neural regions. This accumulation is associated with cell death and muscle fiber swelling, eventually leading to respira...

Aspiration of food containing bacteria or saliva into the trachea, leading to bacterial lung infection, is termed aspiration pneumonia. In the United States, aspiration pneumonia results in over 57,000 deaths annually, constituting 2.3% of the total mortality. Similarly, according to data from 2021 in Japan, more than 49,000 individuals succumbed t...

Purpose Postoperative pneumonia remains a common complication of surgery, despite increased attention. The purpose of our study was to determine the effects of routine surgery and post-surgical opioid administration on airway protection risk. Methods Eight healthy adult cats were evaluated to determine changes in airway protection status and for e...

Opioids are well-known to cause respiratory depression, but despite clinical evidence of dysphagia, effects of opioids on swallow excitability and motor pattern are unknown. We tested the effects of the clinically-relevant opioid buprenorphine on pharyngeal swallow and respiratory drive in male and female rats. We also evaluated the utility of 5-HT...

Systemic administration of opioids has been associated with aspiration and swallow dysfunction in humans. We speculated that systemic administration of codeine would induce dysfunctional swallowing and that this effect would have a peripheral component. Experiments were conducted in spontaneously breathing, anesthetized cats. The animals were trach...

Opioids are well-known to cause respiratory depression, but despite clinical evidence of dysphagia, the effects of opioids on swallow excitability and motor pattern are unknown. We sought to test the effects of the clinically-relevant opioid buprenorphine on pharyngeal swallow and respiratory drive in male and female rats. We also evaluated utility...

Introduction Pompe disease is an inherited disease characterized by a deficit in acid-α-glucosidase (GAA), an enzyme which degrades lysosomal glycogen. The phrenic-diaphragm motor system is affected preferentially, and respiratory failure often occurs despite GAA enzyme replacement therapy. We hypothesized that the continued use of diaphragm pacing...

The objective of our study was to determine the role of 5-HT 1A receptors in modulating breathing and swallowing following opioid administration. Our previous experiments in anesthetized male and female Sprague Dawley rats demonstrated that swallow is suppressed by the opioid buprenorphine, and that female rats are more susceptible to buprenorphine...

One of the rehabilitation methods in practical use for dysphagia is electrical stimulation therapy, usually by stimulating the anterior neck muscles via surface electrodes. Electrostimulation therapy does not directly induce swallowing, but is used as resistance training or to alter drive to swallow muscles. Techniques to stimulate the sensory nerv...

Breathing is a singularly robust behavior, yet this motor pattern is continuously modulated at slow and fast timescales to maintain blood-gas homeostasis, while intercalating orofacial behaviors. This functional multiplexing goes beyond the rhythmogenic function that is typically ascribed to medullary respiration-modulated networks and may explain...

Stimulation of the sensory nervous system has been investigated as a rehabilitation method to activate the entire swallowing reflex circuit. We have investigated the effects of frequency and location of electrical stimulation on swallowing movements. Biphasic bursts of stimulation pulses were applied to either the back or neck of adult rats at a ra...

Effective cough requires a significant increase in lung volume used to produce the shear forces on the airway to clear aspirated material. This increase in tidal volume during cough, along with an increase in tidal frequency during bouts of paroxysmal cough produces profound hyperventilation and thus reduces arterial CO2. While there are several re...

The coordination of swallowing with breathing, in particular inspiration, is essential for homeostasis in most organisms. While much has been learned about the neuronal network critical for inspiration in mammals, the pre–Bötzinger complex (preBötC), little is known about how this network interacts with swallowing. Here we activate within the preBö...

BackgroundX-linked myotubular myopathy (XLMTM) is a life-threatening congenital myopathy that, in most cases, is characterized by profound muscle weakness, respiratory failure, need for mechanical ventilation and gastrostomy feeding, and early death.Objective We aimed to characterize the neuromuscular, respiratory, and extramuscular burden of XLMTM...

Opioid exposure during gestation can lead to neonatal opioid withdrawal syndrome (NOWS) at birth. A feature of NOWS is dysphagia. To better understand the contribution of dysregulated central control to dysphagia in NOWs infants, we compared fictive swallow in neonate (P2-P6) control mice and mice exposed to methadone from E14.5 onwards. Propriobul...

Opioid use is associated with increased risk of chest infection due to opioid suppression of immune function, ventilation, cough, and secretion mobilization. Buprenorphine is a highly lipophilic, semi-synthetic partial agonist of the mu opioid receptor. Intramuscular buprenorphine is commonly used for post-operative analgesia at a dose range of 0.0...

Swallow is a critical behavior for sustaining life, important for both for the ingestion of nutrients and for protecting the airways. To produce an effective swallow, neural circuits must coordinate over 20 muscles across multiple cranial/spinal nerves to produce a rostral-caudal pressure gradient to move the bolus from the mouth to the stomach. Th...

Airway protection is maintained through a constellation of behaviors. The laryngeal adductor reflex (LAR) responds to mechanical or chemical stimulation of the laryngeal orifice with rapid adduction of the vocal folds. While there are abundant serotonin receptors on laryngeal motoneurons, the effects of serotonin agents on the LAR have not been inv...

We employed computational modeling to investigate previously conducted experiments of the effect of vagal afferent modulation on the cough reflex in an anesthetized cat animal model. Specifically, we simulated unilateral cooling of the vagus nerve and analyzed characteristics of coughs produced by a computational model of brainstem cough/respirator...

Brainstem respiratory neuronal network significantly contributes to cough motor pattern generation. Neuronal populations in the pre-Bötzinger complex (PreBötC) represent a substantial component for respiratory rhythmogenesis. We studied the role of PreBötC neuronal excitation and inhibition on mechanically induced tracheobronchial cough in 15 spont...

Proper function of the larynx is vital to airway protection, including swallow. While the swallow reflex is controlled by the brainstem, patients with cervical spinal cord injuries (cSCI) are likely at increased risk of disordered swallow (dysphagia) and pneumonia, and the underlying mechanisms are unknown. We aimed to determine if acute spinal cor...

Due to advances in technology, the number of users with hearing devices has increased. These users are often mainstreamed into classrooms with typical hearing peers. However, even with these devices, speech and language impairments may still persist. This study was conducted to analyze school-based speech- language pathologists’ (SLP) comfort, conf...

The role of the cerebellum in controlling the cough motor pattern is not well understood. We hypothesized that cerebellectomy would disinhibit motor drive to respiratory muscles during cough. Cough was induced by mechanical stimulation of the tracheobronchial airways in anesthetized, spontaneously breathing adult cats (8 male, 1 female), and electr...

Swallow is a complex behavior that consists of three coordinated phases: oral, pharyngeal, and esophageal. Esophageal distension (EDist) has been shown to elicit pharyngeal swallow, but the physiologic characteristics of EDist-induced pharyngeal swallow have not been specifically described. We examined the effect of rapid EDist on oropharyngeal swa...

Autism spectrum disorder (ASD) is a lifelong neurodevelopmental disorder that consists of difficulties with social communication and language, as well as the presence of restricted and repetitive behaviors. These deficits tend to present in early childhood and usually lead to impairments in functioning across various settings. Moreover, these defic...

Muscle injury is a frequent side effect of radiation treatment for head and neck cancer. To understand the pathophysiology of injury-related dysfunction, we investigated the effects of a single muscle injury to the mylohyoid on oropharyngeal swallowing function in the rat. The mylohyoid protects the airway from food/liquid via hyolaryngeal elevatio...

The study investigates the effects of 6 occlusion conditions on the mechanically induced cough reflex in 15 anesthetized (pentobarbital) spontaneously breathing cats (14♂, 1♀). Esophageal pressure and integrated EMG activities of inspiratory (I) diaphragm and expiratory (E) abdominal muscles were recorded and analyzed. Occlusions: inspiratory (Io),...

Lung volume is modulated by sensory afferent feedback via vagal and spinal pathways. The purpose of this study was to systematically alter afferent feedback with and without a mechanical challenge (chest compression). We hypothesized that manipulation of afferent feedback by nebulization of lidocaine, extra-thoracic vagotomy, or lidocaine administr...

Swallow-breathing coordination is influenced by changes in lung volume, which is modulated by feedback from both vagal and spinal sensory afferents. The purpose of this study was to manipulate feedback from these afferents, with and without a simultaneous mechanical challenge (chest compression), in order to assess the influence of each sensory pat...

Afferent feedback can appreciably alter the pharyngeal phase of swallow. In order to measure the stability of the swallow motor pattern during several types of alterations in afferent feedback, we assessed swallow during a conventional water challenge in four anesthetized cats, and compared that to swallows induced by fixed (20 Hz) and stochastic (...

The laryngeal adductor reflex (LAR) is a fundamental airway protective behavior that prevents penetration of material from the upper airway into the trachea. Aspiration risk increases in humans after a single dose of an opioid and pneumonia is a common occurrence in opioid users. The LAR consists of a short latency (~10 ms), short duration (~10 ms)...

Swallow and breathing are tightly coordinated behaviors in which disruption of this coordination leads to aspiration pneumonia, the leading cause of death in many adult and pediatric diseases. Little is known about the neural coordination of these two behaviors. Previous work in the respiratory column has shown activity in swallow‐related and breat...

The central autonomic control system provides parasympathetic and sympathetic drive to peripheral ganglia that regulate a host of visceral functions. Detailed knowledge of the network scale organization of this central circuit is incomplete. We hypothesized that functional synaptic interactions between many simultaneously recorded neurons in and ar...

Opioid use increases the risk of aspiration and pneumonia, presumably through depression of protective reflexes that prevent intrusion of foreign material into the airways. The laryngeal adductor reflex (LAR) is an airway protective behavior that utilizes bilateral thyroarytenoid (TA) muscles and prevents material entering the trachea and lungs. Th...

Laryngeal dysfunction is a common symptom following cervical spinal cord injury (cSCI) and currently there are no effective pharmacological interventions or behavioral treatments. The larynx is the primary valve controlling entrance into the trachea and lungs via opening and closing of the vocal folds. Although not well studied following cSCI, it i...

Cervical spinal cord injuries (cSCIs) can cause swallow disorder (dysphagia), potentially resulting in aspiration and pneumonia. Dysphagia is characterized by disruption of the swallow motor pattern, which involves sequential activation of muscles that propels the bolus into the esophagus while avoiding the airway. Normal swallow includes diaphragm...

Videofluoroscopy is the gold standard for clinical measurement of swallow disorders (dysphagia). Patients are presented with foods and liquids of varying consistencies in order to evaluate the risk of aspiration. The Modified Barium Swallow Impairment Profile (MBSImP) was developed in 2008 and has since become the primary tool to define the degree...

The laryngeal adductor reflex (LAR) is a protective behavior induced by stimulation of upper airway afferents. Laryngeal afferent information reaches interneurons in the medulla via the superior laryngeal nerve (SLN). Expiratory laryngeal motoneurons (ELMs) are subsequently excited causing contraction of the thyroarytenoid (TA) and posterior cricoa...

We studied the effects of GABA receptor agonists microinjections in medullary raphé on the mechanically induced tracheobronchial cough response in anesthetized, unparalyzed, spontaneously breathing cats. The results suggest that GABA-ergic inhibition significantly contributes to the regulation of cough reflex by action of both GABAA and GABAB recep...

Muscle injury is a frequent side effect of radiation treatment for head and neck cancer. To understand the pathophysiology of injury-related dysfunction, we investigated the effects of a single muscle injury to the mylohyoid on oropharyngeal swallowing function in the rat. The mylohyoid protects the airway from food/liquid via hyolaryngeal elevatio...

Respiratory variability is important in order to respond to internal and external perturbations. While vagal afferents have been shown to be important for feedback during breathing, the influence of spinal afferents has not been as well described. We hypothesized that disruption of vagal and spinal afferents reduces respiratory variability during e...

Systemic administration of opioids has been associated with aspiration and swallow dysfunction in humans. The extent to which these outcomes are due to solely central, or both central and peripheral actions, of these drugs is unknown. Codeine is a commonly prescribed opioid that has both central and peripheral actions to affect the cough reflex in...

The ventral respiratory column (VRC) contains heterogeneous neurons that generate and regulate respiration as well as other orofacial behaviors. In neonate SD rat, the VRC extends over 2 mm from the rostral margin of the facial nucleus (VIIn). In addition, networks that modulate breathing on a cycle‐to‐cycle basis are distributed along the dorsomed...

The laryngeal adductor reflex (LAR) is a simple airway protective behavior that closes the vocal folds in response to mechanical or chemical stimulation of sensory afferents in the larynx. Previous work suggested that the intra‐medullary pathway that is responsible for activating laryngeal motoneurons is composed of as little as two synapses. We sp...

Swallow disorder (dysphagia) can cause aspiration and lead to pneumonia in a number of patient populations, including individuals with cervical spinal cord injury. Dysphagia is characterized by dysfunction in the swallow motor pattern, which is a sequential activation of muscles that propels the bolus into the esophagus and prevents entry into the...

Muscle position feedback, via receptors for stretch (muscle spindles) and force (golgi tendon organs), is critical for the muscular coordination and proprioception that is essential for most movements. Muscle spindles are innervated by gamma motoneurons that modulate their sensitivity to stretch. Recent reports suggest that 5‐HT 1D receptors can mo...

Prior work exploring the role of the cerebellum in cough has been limited to paralyzed preparations. Xu et al. (1997) found in paralyzed, artificially ventilated, and decerebrated cats that after cerebellectomy cough number and expiratory magnitude was reduced with no change in phrenic bursting. However, we hypothesized that the cerebellum would ha...

Atropine, a muscarinic acetylcholine receptor antagonist, is a commonly used drug to reduce mucous production during surgery. Because atropine blocks the parasympathetic action of acetylcholine, atropine may modulate the balance of parasympathetic and sympathetic activity. In jaw muscles, increased sympathetic drive decreases muscle contractility a...

Purpose While factors leading to hypoventilation have been well studied in Pompe disease, cough effectiveness and airway clearance practices are less understood. We aimed to identify significant factors that influence peak cough flow (PCF) in Pompe, and to detect whether pulmonary hygiene practices were reflective of reduced PCF. Methods This is a...

Anatomical connections are reported between the cerebellum and brainstem nuclei involved in swallow such as the nucleus tractus solitarius, nucleus ambiguus, and Kölliker-fuse nuclei. Despite these connections, a functional role of the cerebellum during swallow has not been elucidated. Therefore, we examined the effects of cerebellectomy on swallow...

In humans, women are more debilitated by chronic coughing, report to physicians for cough more frequently, and have a greater cough sensitivity than men. These sex differences between men and women begin to emerge at the end of puberty. We conducted a retrospective analysis in anesthetized cats to determine if sex differences could be identified in...

The effects of cervical hemisection on swallow have not been determined. We hypothesized that cervical hemisection would increase swallow excitability and shift the pattern of swallow breathing coordination to maintain pharyngeal clearance. Electromyograms of the mylohyoid, geniohyoid, thyrohyoid, thyroarytenoid, thyropharyngeus, cricopharyngeus an...

The effects of esophageal mechanoreceptors on the pharyngeal phase of swallow have not been determined. We hypothesized that rapid activation of esophageal mechanoreceptors would increase swallow excitability to ensure successful movement of the bolus from the pharynx into the esophagus. Electromyograms of the mylohyoid, geniohyoid, thyrohyoid, thy...

Action of the diaphragm is necessary for negative force production during breathing and cough. However, the effect of cervical spinal cord injury on action of the diaphragm during cough is not known. It was hypothesized that C2 hemisection would result in a loss of cough excitability and depression of the diaphragm during breathing and cough. Elect...

Purpose: Airway protective behaviors, like cough and swallow, deteriorate in many populations suffering from neurologic disorders. While coordination of these behaviors has been investigated in an animal model, it has not been tested in humans. Methods: We used a novel protocol, adapted from previous work in the cat, to assess cough and swallow...

Active contraction of the diaphragm and other inspiratory pump muscles during swallow create a negative thoracic pressure to improve the movement of the bolus (food/liquid) into the esophagus. We tested the hypothesis that dorsomedial medullary inspiratory neurons, including the nucleus tractus solitarius (NTS, pre-motor to the phrenic) would be ac...

NC3Rs ARRIVE guidelines checklist. (PDF)

Autism spectrum disorder (ASD) is a heterogeneous neurodevelopmental disorder whose symptoms may involve deficits across three domains: communication, socialization and atypical behaviors or interests. With a high prevalence across populations and a tendency to impact males more than females, early and accurate diagnosis appears critical. The most...

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...