Swallowing - Module 9

Anatomical Participants

Includes structures within respiratory, laryngeal,velopharyngeal-nasal, and pharyngeal-oral systems

Includes chest wall, vocal folds, ventricular folds, epiglottis, pharynx, velum, tongue, mandible, lips

Also, esophagus and stomach

- Valve at top of esophagus is called upper esophageal sphincter(UES)

Phases (stages) of a Swallow

Oral preparatory - voluntary

Oral transport - voluntary

Pharyngeal transport - reflexive

Esophageal transport - reflexive

Oral Preparatory Phase

Voluntary

Begins as soon as food enters mouth

Highly variable in duration (3-20 sec)

Purpose: prepare bolus for swallow

Steps:

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

Elevate back of tongue to velum to form back wall

- separates oral from pharyngeal cavity

- VP open so person can breathe

Oral Transport Phase

Voluntary

~1 sec

Purpose: Move bolus into pharynx, initiate pharyngeal phase

Steps:

- 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

Reflexive

- Automatic sequence of events triggered when bolus passes anterior faucialpillars

- Series of rapid coordinated movements between pharyngeal muscles, lips,velum, epiglottis, hyoid bone, false vocal folds and true vocal folds

500-800 msec

Purpose: Propel bolus into esophagus

Steps:

- 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 forwardby elevation of larynx

Esophageal Transport Phase

Reflexive

- Initiated shortly after bolus enters esophagus

8-20 sec

- Liquids faster than solids

Purpose: move bolus through esophagus into stomach

Steps

- 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

Phase Overlap

We describe the phases as a series of events, they can overlap

Oral prep phase may continue while part of bolus moves into pharynx

Action Overlap

Overlap of phases is apparent if the actions of individual structures are considered rather than the status of the bolus

Initiation of actions of selected structures during a swallow

Breathing and Swallowing

Must coordinate breathing and swallowing to avoid aspiration

Usually occurs during expiratory phase

Typical pattern is expiration-swallow-expiration

Apnea (no breathing) lasts about 1 sec during Pharyngeal Transport phase

What participate in swallowing?

All of the articulators as well as the esophagus and stomach

What are the four phases of swallowing?

Oral Preparatory

OralTransport

Pharyngeal Transport

Esophageal Transport

OP & OT are voluntary; PT & ET are reflexive

These phases can sometimes overlap

When does breathing stop?

During the Pharyngeal Transport phase for about 1 sec while the airway is blocekd to protect it from aspiration

Abnormal Swallowing

Dysphagia - difficulty in swallowing

Generally results from neuromuscular or structural changes inoral cavity, pharynx, or larynx

- e.g. stroke, neurologic disease, head and neck cancer surgery, radiation Rxfor head and neck cancer, traumatic brain injury

Many of these causes are also causes of communication disorder

- Not surprising since using same structures

Dysphagia generally divided in two categories

- Oropharyngeal

- Esophageal

Symptoms

Oral Preparatory Phase

- food spills into lateral oral sulci or base of tongue

- poor control of bolus

Oral Transport Phase

- food remains in mouth

- poor control of bolus for propulsion

Pharyngeal Transport Phase

- Residue

- Aspiration

- Penetration

- UES stays closed

Esophageal Transport Phase

- poor peristalsis

- reflux

Measuring Swallowing Function

Videoflouroscopy

Endoscopy

Manometry

Surface Electromyography

Ultrasonography

Aeromechanical Observations

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

Same approach used to look at velopharyngeal mechanism

Person swallows substances mixed with barium sulphate

- Contrast material that allows bolus to be tracked visually as it travels through oral, pharyngeal, and esophageal regions

Endoscopy

Uses flexible endoscope inserted nasally and positioned in pharynx

Approach commonly referred to as Flexible Endoscopic Evaluation of Swallowing (FEES)

Observe person swallowing food or liquid that may be colored to aid in visualization of bolus

Ultrasonography

The transducer generates a signal that reflects back when it encounters airand is picked up by a senso

Can be used to image tongue and pharyngeal movements during swallowing

Tongue Force (Force Bulb)

Similar instrument clinically used for tongue force as part of dysphagia intervention

What is dysphagia?

Difficulty in swallowing

Can manifest in a variety of ways in the different phases of swallowing

What does dysphagia result from?

Generally results from neuromuscular or structural changes in oral cavity, pharynx, or larynx

Dysphagia generally divided in two cavitites

Oropharyngeal

Esophageal

What are two common methods of measuring/evaluating swallowing function?

Videofluoroscopy

Endoscopy (FEES)