Project Summary
In a large number of infants, both with and without underlying diseases or disorders, feeding poses significant
challenges because they lack the ability to coordinate movements of tongue, jaw, and pharynx. Failure to
coordinate these movements can lead to dysphagia which has significant short- and long-term impacts on
health. With weaning, the tongue must produce more complex movements and deformations in coordination
with jaw movements to manage a solid, multi-textured diet during bolus transport and processing prior to the
pharyngeal swallow. Failure to do so can quickly result in airway blockage, choking and even death. Modifying
foods by thickening liquids or pureeing solids can assist with feeding and provide adequate nutrition when
necessary. However, if an infant is maintained on foods lacking a heterogeneous texture, the less they are
challenged with oral processing tasks during critical periods of oral development, leading to further setbacks in
chewing and swallowing. Studies of infant dysphagia in humans and animal models reveal much about the
movements and motor control of the tongue, but this work is based primarily on suckling. In contrast, our
understanding of the development and maturation of feeding in newly weaned infants comes primarily from
studies of jaw movement and motor control during chewing, with little information on associated tongue
movements. Furthermore, we also do not know how long-term use of texture modified foods during critical
periods of oral maturation alters the functional and biomechanical development of the tongue and its
coordination with the jaw. The proposed work will investigate maturation of tongue function, biomechanics and
anatomy, and their effect on oral performance in an animal model for oral physiology and biomechanics. We
will compare animals reared on a varied diet requiring processing (control) to those reared on a single texture
soft diet (treatment). Novel methods for characterizing 3D tongue and jaw movements from biplanar
fluoroscopy will allow characterization of kinematic measurements not feasible in humans. This study will
determine how a widely used texture modification strategy for dysphagia affects the normal sensorimotor and
anatomical development necessary for feeding on solids by completing 3 specific aims for the control and
treatment animals: 1) Characterize the ontogeny and maturation of tongue kinematics and jaw-tongue
coordination during feeding; 2) Describe the longitudinal maturation of the anatomy of tongue musculature. 3)
Evaluate oromotor performance in pigs raised on a varied versus soft diet. This research will provide critical
data on the postweaning feeding mechanism necessary for identifying the physiological, biomechanical and
anatomical basis of pediatric dysphagia. This is essential for optimizing specific treatment and rehabilitation
strategies for normal infants with dysphagia and those with underlying conditions that require long-term
texture-modification of foods. Through completion of the aims, this project will also provide state-of-the art and
clinically-relevant research opportunities for undergraduate, graduate and medical students.
