Physiology of communication

Full Answer Section

1. Bolus Positioning: The tongue cups the bolus against the hard palate. The tip of the tongue typically elevates to the alveolar ridge (the bony ridge behind the upper teeth), while the sides of the tongue maintain lateral seal against the molars to prevent premature spillage into the lateral sulci (spaces between the cheeks and gums).
2. Posterior Propulsion: The tongue progressively moves the bolus posteriorly along the hard palate in a smooth, stripping-like motion. This is primarily achieved by the sequential elevation and contraction of the tongue musculature, including the intrinsic and extrinsic muscles of the tongue (e.g., genioglossus, styloglossus, hyoglossus, palatoglossus).
3. Maintaining Oral Containment: Throughout the oral phase, several structures work to maintain bolus containment within the oral cavity and prevent premature entry into the pharynx:
   • Labial Seal: The lips remain closed, preventing anterior leakage of the bolus.
   • Buccal Tension: The cheeks (buccinator muscles) maintain tension to prevent lateral spillage into the buccal sulci.
   • Soft Palate Elevation: While not fully elevated to close off the nasopharynx (which occurs in the pharyngeal phase), the soft palate begins to elevate slightly to create a posterior ramp and guide the bolus backward.
4. Pharyngeal Swallow Trigger: The oral phase concludes when the leading edge of the bolus passes a specific point in the oropharynx, typically around the faucial arches (the folds of tissue at the back of the mouth) or the base of the tongue. This triggers the involuntary pharyngeal phase of swallowing. The precise location of the trigger point can vary slightly between individuals.

Identify Several Ways the Oral Phase Can Be Disrupted by Disease, Trauma, or Medical Conditions:

The intricate movements and coordination required for the oral phase can be disrupted by a variety of factors:

• Neurological Disorders:
  • Stroke (Cerebrovascular Accident - CVA): Weakness or paralysis of the facial muscles, lips, tongue, or palate can impair bolus manipulation, containment, and propulsion.
  • Traumatic Brain Injury (TBI): Can lead to cognitive deficits affecting awareness of bolus position, motor control impairments, and sensory deficits impacting oral awareness.
  • Parkinson's Disease: Rigidity, bradykinesia (slowness of movement), and tremor can affect tongue movement and coordination, leading to difficulty forming and propelling the bolus.
  • Amyotrophic Lateral Sclerosis (ALS): Progressive muscle weakness affecting the tongue, lips, and jaw can severely impair all aspects of the oral phase.
  • Cerebral Palsy: Motor control difficulties and abnormal muscle tone can affect the precise movements needed for bolus manipulation and propulsion.
• Structural and Anatomical Abnormalities:
  • Oral Cancer and Surgical Resection: Removal of parts of the tongue, palate, or lips can directly impact the structures necessary for bolus control and movement. Radiation therapy can also cause tissue changes and dryness, affecting oral function.
  • Cleft Lip and/or Palate: Incomplete closure of the lip and/or palate can compromise labial and palatal seal, leading to anterior and nasal leakage.
  • Macroglossia (enlarged tongue): Can interfere with normal tongue movement and bolus control.
  • Dental Issues: Missing teeth, poorly fitting dentures, or malocclusion can affect the ability to adequately masticate food, impacting bolus consistency and the efficiency of the oral phase.
• Trauma:
  • Facial Fractures: Injuries to the mandible (jaw), maxilla (upper jaw), or other facial bones can impair jaw movement, lip closure, and tongue function.
  • Oral Burns or Lacerations: Pain and tissue damage can affect the ability to manipulate and propel the bolus comfortably and efficiently.
• Medical Conditions:
  • Xerostomia (dry mouth): Reduced saliva production (due to medications, radiation therapy, or certain medical conditions like Sjögren's syndrome) can impair bolus formation and lubrication, making it difficult to propel.
  • Muscle Weakness (e.g., due to aging, malnutrition, or certain neuromuscular disorders): General muscle weakness can affect the strength and coordination of the oral musculature.
  • Sensory Deficits: Reduced sensation in the oral cavity (e.g., due to nerve damage) can impair awareness of bolus position and the ability to control its movement.

Describe How a Deficit in the Oral Phase Affects the Next Phase of Swallowing (Pharyngeal Phase):

A deficit in the oral phase significantly impacts the pharyngeal phase in several ways:

• Delayed or Absent Pharyngeal Swallow Trigger: If the bolus is not efficiently formed and propelled to the trigger point (faucial arches/base of tongue), the pharyngeal swallow may be delayed or may not trigger at all. This increases the risk of aspiration (food or liquid entering the airway) as the bolus may pool in the valleculae (spaces at the base of the tongue) or pyriform sinuses (pockets in the throat) before the airway closes.
• Poor Bolus Control Entering the Pharynx: Inadequate oral containment can lead to premature spillage of the bolus into the pharynx before the pharyngeal swallow is triggered. This also significantly increases the risk of aspiration, as the airway is not yet protected.
• Increased Residue in the Oral Cavity: Inefficient bolus propulsion can leave residue (remaining food or liquid) in the oral cavity after the swallow. This residue can then be aspirated into the airway after the pharyngeal swallow has occurred (post-swallow aspiration).
• Impact on Bolus Characteristics: Poor mastication or inadequate bolus formation during the oral preparation and oral phases can result in a bolus that is too large, too dry, or of an inconsistent texture. These abnormal bolus characteristics can further challenge the pharyngeal phase, affecting the efficiency of pharyngeal transit and increasing the risk of residue.
• Sensory Feedback Disruption: Deficits in oral sensation can affect the sensory information sent to the brainstem, which is crucial for coordinating the pharyngeal swallow. Reduced or altered sensory input can lead to a less efficient and timely pharyngeal response.

Explain Symptoms You Would Expect to See in a Patient in Light of Possible Deficits of Oral Phase of Swallowing:

A patient with deficits in the oral phase of swallowing may exhibit several observable symptoms:

• Difficulty Chewing Food (if oral preparation is also affected): Taking a long time to chew, food remaining in the mouth, fatigue during meals.
• Drooling or Anterior Leakage of Food/Liquid: Inability to maintain a proper labial seal.
• Food or Liquid Leaking from the Sides of the Mouth: Poor buccal tension and lateral bolus containment.
• Difficulty Forming a Bolus: Food spreading around the mouth, inability to manipulate food into a cohesive ball.
• Prolonged Oral Transit Time: Taking an unusually long time to move the bolus from the front to the back of the mouth.
• Complaints of Food Sticking in the Mouth: Feeling like food is trapped on the tongue or palate.
• Gurgly or Wet Voice After Swallowing: May indicate residue in the pharynx that has not been cleared.
• Frequent Coughing or Throat Clearing During or Immediately After Eating/Drinking: Suggests potential aspiration or penetration (food/liquid entering the larynx but not passing below the vocal folds).
• Complaints of Food or Liquid Going "Down the Wrong Way": A subjective report of aspiration.
• Nasal Regurgitation: If the soft palate doesn't elevate adequately during the oral phase (though more directly a pharyngeal issue, poor oral control can contribute).
• Visible Food Residue in the Oral Cavity After Swallowing: Observed during an oral motor examination.
• Piecemeal Deglutition: Swallowing very small amounts of food or liquid at a time due to difficulty managing a larger bolus.

It is important to note that the severity and combination of these symptoms will vary depending on the underlying cause and the extent of the oral phase deficit. A thorough clinical swallowing evaluation by a speech-language pathologist is crucial for accurate diagnosis and the development of an appropriate management plan.

Sample Answer

The Oral Phase of Swallowing: Physiology and Disruption

The process of swallowing, also known as deglutition, is a complex sensorimotor act that safely and efficiently transports food and liquid from the oral cavity to the esophagus. It is traditionally divided into four overlapping phases: oral preparation, oral, pharyngeal, and esophageal. This response will focus specifically on the oral phase of swallowing.

Research and Describe the Specific Steps of the Oral Phase of Swallowing:

The oral phase is the second voluntary stage of swallowing, initiated once the bolus (chewed food or liquid) is prepared in the oral preparation phase. It involves the controlled movement of the bolus from the front to the back of the oral cavity, culminating in the triggering of the pharyngeal swallow. The specific steps are as follows: