CODI 531  Lecture 1
Normal Swallow Function

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 Definitions

•  Deglutition - the act of swallowing
•  Dysphagia - disordered or abnormal swallowing
•  Feeding disorders
•  Includes swallowing difficulty plus problems involving voluntary placement of food in the mouth
•  Dependent on cognition, upper extremity mobility, oral mobility, taste, smell, vision

 Incidence of dysphagia

•  Dysphagia is not a disease but a symptom of one or more underlying pathologies
•  Estimates of 6-10 million people in US with dysphagia (1989)
•  Stroke is the most common cause of dysphagia
•  Prevalence increases with age

 Phases of the Normal Swallow

•  Oral preparation
•  Oral transition
•  Pharyngeal
•  Esophageal

 Anatomy of Oral Cavity

•  Lips & cheeks
•  Buccal cavity
•  Anterior and lateral sulci
•  Floor of the mouth
•  Tongue
•  Faucial arches
•  Velum

 Laryngeal/Pharyngeal Structures

•  Valleculae
•  Pharyngeal muscles
•  Superior, medial, inferior constrictors
•  Palatopharyngeus,stylopharyngeous, salpingopharyngeus
•  Cricopharyngeus
•  Laryngeal vestibule/airway entrance
•  Pyriform sinuses

 Oral Preparation Stage

•  Functions are to reduce food to consistency for swallow and provide pleasure
•  Components
•  Labial closure
•  Facial tone
•  Lateral and rotary jaw movement
•  Lateral and rotary tongue movement
•  Lingua-velar seal
•  Innervation
•  Cranial nerve V - mandibular movement
•  Cranial nerve VII - lip shape & facial tone
•  Cranial nerve X, XI,V - Velar movement
•  Cranial nerve XII - tongue shape and position

 Oral Stage

•  Function is movement of food/liquid bolus into the pharynx
•  Components
•  Tongue seals around bolus with tip anchored at alveolar ridge
•  Midline of tongue forced upward (mylohyoid, geniohyoid, digastric)
•  Root of tongue pressed against velum (styloglossus, hyoglossus)
•  Propels bolus upward and backward toward faucial arches
•  Innervation
•  Cranial nerve XII - tongue movement
•  Cranial nerve V & XII - floor of oral cavity movement

 Pharyngeal Stage

•  Sensory information from area of faucial arches triggers swallow reflex
•  Components
•  Velopharyngeal closure
•  Narrowing of hypopharynx and posterior movement of base of the tongue
•  Elevation and anterior movement of the larynx
•  Laryngeal closure
•  Relaxation and opening of UES
•  Innervation
•  Cranial nerve V, IX, X, XI - velar movement
•  Cranial nerves V, VII, IX, X, XI, XII - pharyngeal, laryngeal movement
• Cranial nerve IX - sensory input

 Esophageal Stage

•  Peristalsis moves bolus down esophagus
•  LES opens allowing bolus to enter stomach
•  Cranial nerve X
•  Smooth muscle - involuntary control

 Age- related Dysphagia

•  Healthy aged individual
•  Generalized slowing of the swallow function
•  Loss of muscle tone & atrophy
•  Tooth loss
•  Reduced sensitivity to taste & reduced appetite
•  Medically frail elderly
•  Reduced cognitive skills
•  Weaker overall condition
•  Drooling, reduced mastication, reduced salivation
•  GERD

 Swallowing Skills in the Infant: Prenatal Development

•  Begins in utero and continues into early childhood
•  Swallow is evident by about 11-17 weeks gestation
•  Sucking appears around 28 weeks but is not mature until 30 - 34 weeks

 Swallowing Skills in the Infant: Postnatal Development

•  Three periods
•  Nursing - birth to 4- 6 months
•  Transitional
•  Modified adult - near adult level attained by 2-3 years

 Nursing period

•  Tongue is held in cupped configuration with central grooving
•  Swallow is accompanied by tongue protrusion
•  Variations in anatomy
•  Use repeated tongue and/or jaw pumping to express milk
•  Jaw elevation elevates anterior portion of tongue
•  Back of tongue remains depressed to leave space for mild
•  Tongue base & pharyngeal wall come together to drive bolus down
•  Larynx moves forward causing UES to open, arytenoids to tilt forward, epiglottis moves forward

 Transitional period

•  Lips begin to show active movement
•  Active suck-swallow coordinated so child doesn’t have to stop for a breath
•  Chewing reflexes begin & lateral tongue movement seen
•  By end of period lips able to remove food from a spoon, tongue tip begins to elevate, emerging lateral and diagonal jaw and tongue movement

 Modified Adult period

•  Lip & tongue movements occur independent of each other
•  Tongue tip refinement with tongue tip stabilization during swallow
•  Rotary chewing begins and continues to develop throughout this period
•  Essentially normal adult swallow by 2-3 years though refinement in control may continue

 Etiologies of Feeding/Swallowing Disorders in Children

•  Prematurity/low birth weight
•  Neurological disorders
•  Prolonged nonoral feeding
•  Lack of oral-motor stimulation
•  Behavioral including food aversions