Swallowing is a critical human activity;failure seriously compromises health and well-being. Normal swallowing function depends on the bilateral integrity of the peripheral neural pathways for safe and efficient transport of the bolus through the mouth and pharynx. Due to its extensive anatomic course and vulnerability to disease and trauma, injury to the vagus and its laryngeal branches is not an uncommon medical finding across the lifespan. The specific impact of these injuries and the mechanisms causing the associated dysphagia are debated, while the contralateral effects of these nerve injuries are unknown. The overarching objective of this project is to understand the changes in patterns of EMG activity and in oropharyngeal kinematics during pathophysiologic swallowing following nerve injury.
The specific aims i nclude determination of the impact of three independent, unilateral nerve injuries, superior laryngeal nerve (SA1), recurrent laryngeal nerve (SA2) and proximal vagus (SA3), on swallowing in an infant pig model. The response variables include synchronous measurements of the kinematics of oropharyngeal and laryngeal structures and of bolus transit, as well as the EMG activity patterns in the hyoid, soft palate and pharyngeal musculature. We predict that the oro-pharyngeal behavior after these sensory and motor lesions will be disordered in specific ways so that these results can be used to predict specific dysfunctions which, for ethical reasons, can only be incompletely measured in humans. An understanding of the effect of isolated experimental nerve lesions on swallowing is critical to the assessment of naturally occurring dysfunction. This is especially so in this complex system, where one compromised structure can significantly disrupt other components that are interlinked both in terms of mechanics and control systems. The results from this study can ultimately serve as a basis for the design of clinical rehabilitative strategies.

Public Health Relevance

Due to its extensive anatomic course and vulnerability to disease and trauma, injury to the vagus and its laryngeal branches is not an uncommon medical finding across the lifespan. Determination of the functional consequences of such injuries will elucidate how disruption of the biomechanical integrity of the oropharyngeal system produces dysphagia. Establishing the pathophysiologic basis for dysphagia is the first step towards developing an effective rehabilitative strategy for this condition.

Agency
National Institute of Health (NIH)
Institute
National Institute on Deafness and Other Communication Disorders (NIDCD)
Type
Research Project (R01)
Project #
1R01DC009980-01A1
Application #
7782943
Study Section
Motor Function, Speech and Rehabilitation Study Section (MFSR)
Program Officer
Shekim, Lana O
Project Start
2010-02-01
Project End
2015-01-31
Budget Start
2010-02-01
Budget End
2011-01-31
Support Year
1
Fiscal Year
2010
Total Cost
$383,670
Indirect Cost
Name
Johns Hopkins University
Department
Physical Medicine & Rehab
Type
Schools of Medicine
DUNS #
001910777
City
Baltimore
State
MD
Country
United States
Zip Code
21218
Gross, Andrew; Ohlemacher, Jocelyn; German, Rebecca et al. (2018) LVC Timing in Infant Pig Swallowing and the Effect of Safe Swallowing. Dysphagia 33:51-62
Gould, Francois D H; Yglesias, B; Ohlemacher, J et al. (2017) Pre-pharyngeal Swallow Effects of Recurrent Laryngeal Nerve Lesion on Bolus Shape and Airway Protection in an Infant Pig Model. Dysphagia 32:362-373
German, Rebecca Z; Crompton, A W; Gould, Francois D H et al. (2017) Animal Models for Dysphagia Studies: What Have We Learnt So Far. Dysphagia 32:73-77
Gould, Francois D H; Ohlemacher, Jocelyn; Lammers, Andrew R et al. (2016) Central nervous system integration of sensorimotor signals in oral and pharyngeal structures: oropharyngeal kinematics response to recurrent laryngeal nerve lesion. J Appl Physiol (1985) 120:495-502
Druzinsky, Robert E; Balhoff, James P; Crompton, Alfred W et al. (2016) Muscle Logic: New Knowledge Resource for Anatomy Enables Comprehensive Searches of the Literature on the Feeding Muscles of Mammals. PLoS One 11:e0149102
Gould, Francois D H; Lammers, Andrew R; Ohlemacher, Jocelyn et al. (2015) The Physiologic Impact of Unilateral Recurrent Laryngeal Nerve (RLN) Lesion on Infant Oropharyngeal and Esophageal Performance. Dysphagia 30:714-22
Ding, Peng; Fung, George Shiu-Kai; Lin, MingDe et al. (2015) The effect of bilateral superior laryngeal nerve lesion on swallowing: a novel method to quantitate aspirated volume and pharyngeal threshold in videofluoroscopy. Dysphagia 30:47-56
Holman, Shaina Devi; Gierbolini-Norat, Estela M; Lukasik, Stacey L et al. (2014) Duration of action of bupivacaine hydrochloride used for palatal sensory nerve block in infant pigs. J Vet Dent 31:92-5
Holman, Shaina D; Campbell-Malone, Regina; Ding, Peng et al. (2014) Swallowing kinematics and airway protection after palatal local anesthesia in infant pigs. Laryngoscope 124:436-45
Gierbolini-Norat, Estela M; Holman, Shaina D; Ding, Peng et al. (2014) Variation in the timing and frequency of sucking and swallowing over an entire feeding session in the infant pig Sus scrofa. Dysphagia 29:475-82

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