Swallowing

• Swallowing


  The process of moving food or liquid from the mouth to the stomach
• Normal Swallowing


  • Involves four phases: Oral Preparatory, Oral Transport, Pharyngeal Transport, Esophageal Transport
  • Some phases are voluntary, some are reflexive
• Dysphagia


  Difficulty in swallowing
• Causes of Dysphagia


  • Neuromuscular or structural changes in oral cavity, pharynx, or larynx
  • e.g. stroke, neurologic disease, head and neck cancer surgery, radiation therapy for head and neck cancer, traumatic brain injury
• Types of Dysphagia

  • Oropharyngeal
  • Esophageal
• Swallowing Measurement Techniques


  • Videofluoroscopy
  • Endoscopy (FEES)
  • Manometry
  • Surface Electromyography
  • Ultrasonography
  • Aeromechanical Observations
• Swallowing Measurement Tests


  • 3-oz water swallow test (screening for dysphagia)
  • Aspiration Number of swallows/mean volume of swallows
  • Duration/mean time per swallow
  • Swallowing capacity (ml/s)
• Videofluoroscopy


  Person swallows substances mixed with barium sulphate, allowing the bolus to be tracked visually as it travels through the oral, pharyngeal, and esophageal regions
• Endoscopy (FEES)


  Uses a flexible endoscope inserted nasally and positioned in the pharynx to observe the person swallowing food or liquid
• Ultrasonography


  Uses a transducer that generates a signal that reflects back when it encounters air, allowing imaging of tongue and pharyngeal movements during swallowing
• Swallowing includes respiratory, laryngeal, velopharyngeal - nasal and pharyngeal - oral systems
• Swallowing includes chest wall, vocal folds, ventricular folds, epiglottis, pharynx, velum, tongue, mandible, lips, esophagus, stomach
• Oral prep phase is voluntary
• Oral transport phase is voluntary
• Pharyngeal transport phase is reflexive
• Esophageal transport phase is reflexive
• Oral prep phase begins as food enters mouth and can be anywhere from 3 - 20 seconds
• Oral prep phase purpose: Prepare bolus for swallow
• Liquids

  • Elevate mandible and adduct lips to form anterior seal
  • Tongue and other structures contain bolus anteriorly
  • Depress anterior tongue and elevate sides to form “cup”
• Solids

  • mandible (teeth), lips, tongue, cheeks grind and manipulate food into bolus
  • mix bolus with saliva
  • position bolus on anterior surface of tongue
  • lips may remain adducted, but not necessary
• Back of tongue is elevated to velum to form back wall during oral prep phase
• Velopharyngeal port is open during oral prep phase so person can breathe
• Oral transport phase is about 1 second long
• Oral transport phase purpose: Move bolus into pharynx, initiate pharyngeal phase
• Oral Transport Phase

  • Elevate tongue tip and squeeze bolus against hard palate

  • Lips usually press together firmly

  • Cheeks pulled inward slightly to keep bolus positioned over tongue

  • Elevate velum and constrict pharyngeal walls

  • Swipe tongue back along the hard palate

  • Begin to relax UES
• Pharyngeal transport phase is triggered when bolus passes anterior faucial pillars
• Pharyngeal transport phase is 500-800 msec long
• Pharyngeal transport phase purpose: Propel bolus into esophagus
• Pharyngeal transport phase

  • Lips and VP port tightly closed

  • Hyoid bone and larynx moved superiorly and anteriorly

  • Epiglottis covers aditus of larynx

  • False vocal folds, true folds and aryepiglottic folds approximated

  • Pharyngeal constrictors squeeze bolus in downward direction

  • Cricopharyngeus muscle relaxes (opening UES) and is pulled forward

  by elevation of larynx
• Esophageal transport phase is initiated shortly after bolus enters esophagus
• Esophageal transport phase is faster for liquids
• Esophageal transport phase is around 8 - 20 seconds long
• Esophageal transport phase purpose: Move bolus through esophagus into stomach
• Esophageal transport phase

  • Peristaltic contraction moves from striated muscle of upper 1/4 to smooth

  muscle of distal region at about 2-4 cm/sec

  • Lower esophageal (cardiac) sphincter is segment of tonically contracted

  smooth muscle at distal end of esophagus

  • Cardiac sphincter relaxes to allow passage of bolus into stomach
• Oral prep phase may continue while part of bolus moves into pharynx
• Overlap of phases is apparent if the actions of individual structures are considered rather than the status of the bolus
• • Must coordinate breathing and swallowing to avoid aspiration
• • Typical pattern is expiration - swallow - expiration
• Apnea (no breathing) lasts about 1 sec during Pharyngeal Transport phase
• Dysphagia oral prep phase: Food spills into base of tongue, poor control of bolus