Swallowing Anatomy and Physiology

• UES (motor) is primarily innervated by the recurrent laryngeal nerve, with some motor contributions from the pharyngeal plexus, including cranial nerves 9, 10, and 11.

• CN IX (9) refers to the glossopharyngeal nerve

• CN X (10) refers to the vagus nerve.

• CN XI (11) refers to the accessory nerve

• There are sensory components to the UES

• During swallowing, the PES (behind the larynx) constricts, creating a stripping wave.

• The UES opens for the bolus to move further down as the larynx moves.

• Pressure towards the lower esophageal sphincter sends the bolus to the stomach.

• Bolus returning upwards can lead to GERD.

• Laryngeal elevation and excursion (up and forward) make room for the esophageal sphincter.

• The pharynx extends from the nasal cavity to the larynx.

• The velum closes off the nasopharynx.

• Penetration occurs if the bolus goes down but remains above the vocal folds.

• Aspiration occurs if the bolus goes into the lungs, which means it goes below the vocal folds.

• The three pillars of aspiration pneumonia include poor oral health, a compromised immune system, and something to aspirate on.

• Penetration can be caused by incomplete airway closure.

• Aspiration can be caused by ineffective airway protection (ap), weak vocal folds (vf), and reduced sensation due to CNX (vagus nerve) dysfunction.

• Post-swallow aspiration can result from pharyngeal residue overflow.

• Dysfunction can occur in the pyriform sinus

• The tongue has to retract so that the bolus goes beyond the vallecula.

• The epiglottis is on the same side at the top.

• The epiglottis is on opposite sides at the bottom

• The supraglottis and laryngeal vestibule are the same structure.

• The Passy Muir valve cuff must be on for eating.

• The Passy Muir valve cuff must be off for speaking.

• A tracheostomy involves placing a stoma.

• The PES is the vibratory source when there is no larynx due to a total laryngectomy.

• The cerebellum coordinates movement and balance to manage bolus efficiency (BE).

• The oral phase/preparatory phase is voluntary, while everything else in the swallowing process is involuntary.

Possible Neurological Impairments from Hemispheric CVA

• Volitional motor control impairments can lead to initiation and transport difficulties, as well as reduced airway protection.
• Sensory recognition issues may cause impaired swallow initiation timing, undetected residue, and aspiration.
• Communication deficits involving the inability to describe or follow directions.
• Common swallowing deficits include reduced ability to initiate, delayed triggering of the pharyngeal swallow, incoordination of oral movements during swallow, increased pharyngeal transit time, reduced pharyngeal constriction, aspiration, PES dysfunction, and impaired lower esophageal sphincter relaxation.

Brainstem CVA

• May cause delayed or absent pharyngeal response and incomplete swallows
• Typically results in global weakness
• Can affect hyolaryngeal elevation/excursion, oropharyngeal and pharyngeal constriction, and laryngeal closure.
• Reduces PES opening and creates a brief swallow event
• Causes general incoordination, including respiration

Amyotrophic Lateral Sclerosis (ALS)

• Progressive degeneration of upper and lower motor neurons
• Progressive muscle weakness
• Patients usually will need a feeding tube
• Dysphagia and dysarthria are early signs in about 30% of cases
• Weak or absent cough can lead to life-threatening pneumonia

Dysphagia by Stage

• Oral Stage: leakage, mastication issues, and problems with bolus formation, transport, and residual pooling.
• Pharyngeal Stage: nasopharyngeal regurgitation, valleculae pooling, piriform sinus pooling, airway spillage, ineffective airway clearance, and shortness of breath.

Brain Mass

• Brain masses can be compared to CVA when the lesion is matched
• Malignancy doesn't necessarily change the impact on swallow

TBI

• Results in impulsivity, neglect, denial of illness, anger, and memory deficits
• Many patients need a trach or vent, which comes with additional dysphagia complications
• Dysphagia in 60 to 90% of TBI patients

Dementia

• 13-57% of dementia patients will have dysphagia.

• High risk for malnutrition, dehydration, and aspiration pneumonia

• Impacts swallowing and feeding and leads to swallowing deviations, such as slow oral movement, slow or delayed pharyngeal response, overall slow swallowing duration, and/or general weakness.

• Aspiration pneumonia is the most common cause of death in Parkinson's Disease (PD) patients

• Progressive demyelination of the substantia nigra causes reduced dopamine transmission, leading to disordered movement and silent aspiration.

• Both sensory and motor functions can be impacted.

• 55% of Parkinson's patients report xerostomia, possibly related to high doses of levodopa therapy.

Parkinson's Disease Oral Stage

• Lingual tremor
• Repetitive tongue pumping is a common deficit
• Prolonged ramplike posture
• Piecemeal deglutition
• Velar tremor
• Buccal retention is a common deficit

Parkinson's Disease Pharyngeal Stage

• Vallecular and piriform sinus retention are common deficit
• Includes impaired laryngeal elevation, airway (supraglottic) penetration, and aspiration

Cerebellum Damage

• Results in ataxia, intention tremor, and hypotonia which can result in impaired coordination in swallowing, poor bolus control, delayed oral transport, variable pharyngeal response timing, reduced strength, and variable laryngeal closure timing.
• Progressive Supranuclear Palsy (degeneration of extrapyramidal tract) is similar to PD.
• Most patients have dysphagia that does not respond to medication.
• Causes uncoordinated lingual movements, absent retraction/elevation, and increased pharyngeal secretions.

Spinal Cord Injury

• Impacts swallowing if the cervical spine is involved because it impacts respiratory function
• High risk of pulmonary complications
• Sequela of neurological impairment of the muscles of autonomic changes
• Cascade of pulmonary events that increase the work of breathing.
• The protective cough reflex is often disrupted by medical conditions and neurologic weakness.
• The majority of dysphagia is in the pharyngeal phase.

Important brain regions for swallowing

• Aspects under voluntary versus involuntary control and its relationship to different neurological diagnoses
• Key dysphagia traits with diagnoses of dementia, TBI, PD, or stroke

HNC Cases

• Primary treatments and effects on swallowing
• Common dysphagia traits within this patient population

Airways Cases

• Differences between total laryngectomy and tracheostomy
• Functions of one-way valves for each airway type
• Ways to explain changes in breathing, communication, swallowing in each

Esophageal Cases

• Basic knowledge of appropriate assessments
• Knowledge of structural issues
• Common symptoms of GERD/LPR

Aspiration Pneumonia

• Includes definition and risk factors
• Langmore 1998 risk factors