Fiberoptic Endoscopic Evaluation of Swallowing (FEES) is a crucial diagnostic procedure for individuals suffering from neurogenic dysphagia. This condition, where swallowing difficulties arise from neurological impairments, affects a significant number of neurological patients, especially those who have experienced an acute stroke. Understanding FEES, its process, and its importance is key for students in healthcare fields.

At least 50% of neurological patients experience oropharyngeal dysphagia, which dramatically increases their risk of developing pneumonia and leads to poorer health outcomes. FEES provides an objective and early assessment, helping to identify swallowing problems and guide appropriate interventions.

What is FEES for Neurogenic Dysphagia?

FEES for neurogenic dysphagia is a well-established and widely used method for evaluating patients with oropharyngeal dysphagia, particularly when it's caused by neurological conditions. It was developed by Dr. Susan Langmore in 1988 and has since advanced with high-resolution imaging, allowing for clear differentiation of anatomical structures in the pharynx and evaluation of the swallowing act.

FEES is performed by laryngologists, phoniatricians, and speech-language pathologists, and increasingly by neurologists with specialized training. Its primary goals include objectively evaluating deglutition (swallowing), determining the risk of aspiration (food or liquid entering the airway), detecting silent aspirations (aspiration without protective reflexes like coughing), and implementing early therapeutic measures.

Why is FEES Important in Neurogenic Dysphagia?

FEES plays a vital role in patient care due to several key factors:

Early Detection: It's an important tool for early evaluation in neurological patients with suspected dysphagia.
Silent Aspiration: FEES can reveal silent aspirations even when patients show no clinical evidence of them.
Accessibility: It's more accessible for evaluating acute, bedside patients, especially those with immobility or altered consciousness in stroke units.
No Radiation: Unlike videofluoroscopy (VFSS), FEES does not expose patients to radiation, allowing for repeated examinations to monitor dysphagia progress.
Detailed View: It offers a better view of larynx movement and is particularly effective for evaluating the pharyngeal phase of swallowing, visualizing secretions, penetrations, and assessing the efficacy of protective mechanisms and pharyngeal sensibility.
Post-Swallowing Residues: Especially useful for evaluating residues left in the throat after swallowing.

Basic Anatomy and Functional Concepts of Swallowing

Swallowing is a complex process, traditionally divided into four stages:

Oral Preparatory Phase: Food or fluid is introduced into the mouth, chewed, and moved by the tongue. The soft palate (velum) descends to prevent premature entry into the oropharynx. Risk of aspiration can occur here with mixed consistencies if the tongue-velum closure is absent.
Oral Transport Phase: The bolus (chewed food or liquid) is moved from the mouth into the oropharynx.
Pharyngeal Phase: This begins when the bolus reaches the palatoglossal arch, triggering the swallowing reflex. It's a rapid phase (0.5-1.5 seconds) that protects the airway by closing the vocal cords and descending the epiglottis, directing the bolus into the esophagus. A brief "white-out" period is observed during endoscopy.
Esophageal Phase: The upper esophageal sphincter closes, and peristaltic waves in the esophagus transport the bolus to the stomach.

Central Control of Swallowing

Swallowing is controlled by a complex neural network involving numerous brain structures:

Cortical Regions: Somatosensory cortex, supplementary motor area, operculum, prefrontal and inferior frontal cortex, cingulate cortex, insular cortex, thalamus, basal ganglia, cerebellum.
Brainstem: Pons and medulla, which house the pontomedullary swallowing center.

Cortical control dominance varies, with the left hemisphere typically controlling preparatory and oral transport phases, and the right hemisphere predominantly controlling the pharyngeal phase. Lesions in specific areas can lead to distinct swallowing impairments, such as delayed swallowing initiation, altered hyoid movement, or impaired laryngeal vestibular closure.

Clinical Indications and Screening for FEES

FEES should be considered in any patient suspected of dysphagia, especially those with:

Compromised pulmonary clearance.
Difficulties managing secretions.
Positioning problems that make other assessments difficult.
Unavailable fluoroscopy.
Severe dysarthria (speech difficulty), facial palsy, or aphasia.

Neurological diseases commonly associated with dysphagia include:

Acute stroke.
Parkinson's disease.
Neuromuscular diseases (e.g., myasthenia gravis, motor neuron disease with bulbar affection).
Acute inflammatory demyelinating polyneuropathy.

Dysphagia Screening

Before FEES, a validated standard screening tool is recommended for initial patient evaluation. Examples include:

Volume-Viscosity Swallow Test (V-VST)
Standardized Swallowing Assessment (SSA)
90 ml screening test
2-6 scale by Daniels

These tests can be performed by various healthcare providers. The V-VST is particularly pragmatic for bedside screening due to its high accuracy and feasibility, allowing initial therapeutic measures regarding oral intake based on different viscosities.

The FEES Procedure: A Step-by-Step Guide

FEES is performed with the patient in a sitting position, typically after applying a local anesthetic in the nasal cavity. The endoscope is carefully guided into the nasal cavity, caudally and posteriorly.

Pre-Swallowing Observation:

Velopharyngeal Closure: Observe velum elevation by asking the patient to say explosive and fricative words (e.g., "coco, cuca come queso").
Oropharyngeal View (Home Position): Assess anatomical symmetry, ventilation, and phonation positions.
Phonetics and Vocal Cord Closure: Ask the patient to say "iiiii" for 2-3 seconds, varying pitch. Observe vocal cord mobility and closure.
Protective Mechanisms: Ask the patient to cough, clear their throat, and perform the Valsalva maneuver to observe vocal cord closure.
Pharyngeal Squeeze Maneuver: Patient performs an "eeeee" phonation to assess pharyngeal strength.
Sensibility Evaluation: Gently touch hypopharyngeal structures with the endoscope tip, though this can be uncomfortable and trigger protective reactions.
Signs of Impaired Swallowing: Look for reduced swallowing frequency, secretions, and food residues in areas like the base of the tongue, valleculae, piriform sinuses, and laryngeal vestibule. Note any penetration or aspiration.

Observation of Swallowing with Different Consistencies:

Pureed/Mashed Foods: Such as fruits and vegetables.
Thickened Water: Crucial for founding diet recommendations; effects must be objectively evaluated.
Fluids: Start with one to two teaspoons, then a glass. Using milk or green dye can enhance visualization of penetration and aspiration.
Solid Foods: Examples include toasted bread and banana.

Restitution Maneuvers: Perform and evaluate maneuvers like the Masako-Maneuver (tongue hold), chin tuck, and head rotation (ipsi- and contralateral).

Pathological Findings in FEES

Key pathological findings identified during FEES include:

Leaking: Uncontrolled premature escape of bolus parts into the pharynx.
Delayed Swallowing Reflex: Fluid bolus reaches the vallecula, and the patient swallows after 3 seconds; with dry food, the reflex should occur within 2 seconds.
Penetration: Material enters the laryngeal aditus, above the vocal cords.
Aspiration: Material passes through the vocal cords into the subglottic region (trachea).
Silent Penetration/Aspiration: Occurs without activation of protective mechanisms like coughing or throat-clearing.
Retention (Residues): Remnants of bolus material in the hypopharynx after a swallow.
Hypersalivation/Poor Clearing: Can indicate reduced sensibility or reflux.

FEES-Tensilon Test: Diagnosing Neuromuscular Disease

The FEES-Tensilon test is a specialized application of FEES used to diagnose neuromuscular diseases, particularly Myasthenia Gravis, in patients with predominantly bulbar symptoms. It involves performing FEES in combination with the Tensilon test, where 30 consecutive white bread pieces are swallowed (fatigable swallowing test). Increased residues after 5-10 swallows can be indicative.

Documenting FEES Findings: Scales and Protocols

After performing FEES, a systematic description of pathological findings using validated scales is recommended to improve interpretation accuracy. Key scales include:

Simplified Murray Secretion Scale:

0: Normal (no secretions)
1: Pooling in valleculae/pyriform sinus
2: Pooling in laryngeal vestibule transiently
3: Pooling in laryngeal vestibule consistently

Yale Pharyngeal Residue Severity Rating Scale: A five-point scale for post-swallow residue severity, described separately for the epiglottic vallecula and pyriform sinus (0% none, 1-5% trace, 5-25% mild, 25-50% moderate, >50% severe).
Penetration-Aspiration Scale (PAS): An 8-point rating scale for penetration and aspiration:

1: No entry.
2: Material enters larynx, cleared.
3: Material enters larynx, no clearing.
4: Material contacts true vocal folds, cleared.
5: Material contacts true vocal folds, no clearing.
6: Material enters trachea, spontaneously cleared.
7: Material enters trachea, not cleared after attempts.
8: Material enters trachea, no attempt to clear.

Note: PAS 2 can occur in healthy individuals and should only be considered abnormal within the clinical context.

Severity Scales for Dysphagia

Fiberoptic Endoscopic Dysphagia Severity Scale (FEDSS): This scale independently predicts outcomes and complications in acute stroke patients. Each 1-point increase more than doubles the risk of pneumonia.

Score 6 (Severe): Saliva penetration/aspiration. Recommendation: Non per os (no oral intake), gastric tube, protective endotracheal intubation.
Score 5 (Moderately Severe): Soft bite/easy chew food penetration/aspiration with reduced/absent protective reflexes. Recommendation: Non per os, gastric tube.
Score 4 (Moderate): Soft bite/easy chew food penetration/aspiration with normal protective reflexes; OR Fluid penetration/aspiration with reduced/absent protective reflexes. Recommendation: Logopedic therapy, eventually gastric tube.
Score 3 (Mild-Moderate): Fluid penetration/aspiration with normal protective reflexes. Recommendation: Logopedic therapy, dysphagia-adapted diet, eventually intravenous fluids.
Score 2 (Mild): Hard/dry food penetration/aspiration, severe residues. Recommendation: Logopedic therapy, dysphagia-adapted diet, oral fluids.
Score 1 (Minimal): Hard/dry food, no penetration/aspiration, no relevant residues. Recommendation: Regular or transitional foods.

Simplified Dysphagia Severity Rating Scale (DSRS): Based on oral intake and supervision requirements, useful for post-stroke patients.

Score 4: No oral fluids/No oral feeding.
Score 3: Pudding consistency/Puree (therapeutic feeding).
Score 2: Custard consistency/Soft, moist diet (feeding by untrained third party).
Score 1: Syrup consistency/Selected textures (eating with supervision).
Score 0: Normal diet/Eating independently.

These scales provide objective measures for determining therapeutic consequences and developing an appropriate treatment plan.

Therapeutic Decisions and Follow-up with FEES

FEES plays a critical role in guiding therapeutic decisions. For instance, insertion of a gastric tube might be necessary for patients with penetration/aspiration of saliva, soft foods, or fluids without effective protective reflexes. Persistent aspiration of saliva, secretions, or stomach content, ineffective cough, and recurrent pneumonia are indications for tracheotomy.

For fluid aspiration/penetration, thickened fluids can be an alternative, but their effectiveness must be objectified with FEES before recommendation.

FEES in the Acute Phase and Rehabilitation

In acute neurological patients, especially stroke patients, FEES should be performed promptly (within 24-48 hours) upon hospital admission. This facilitates swift therapeutic decisions regarding oral intake and diet modification. Early rehabilitation, guided by FEES findings, improves clinical outcomes.

Follow-up FEES examinations are crucial during the rehabilitation phase, particularly for patients with tracheostomy tubes, to allow for earlier resumption of oral feeding and implementation of symptom-oriented dysphagia therapy. The collaboration of laryngologists, phoniatricians, and speech-language pathologists is essential for an interdisciplinary approach to dysphagia evaluation and treatment.

FEES vs. Videofluoroscopy (VFSS)

While VFSS is considered the "gold standard" for dysphagia evaluation, FEES offers distinct advantages:

Accessibility: FEES is more accessible for bedside evaluation of acute, immobile, or conscious-altered patients.
Radiation: FEES avoids radiation exposure, allowing for repeated examinations.
Visualization: FEES provides a better, real-time view of larynx movement and is highly sensitive for visualizing silent aspiration and post-swallowing residues.
Complementary: The findings of both FEES and VFSS are complementary, providing comprehensive information for intervention and rehabilitation strategies.

Both methods effectively guide therapeutic measures and have not shown significant differences in clinical outcome or impact on pneumonia incidence. However, long-term outcomes depend on many variables, including risk factors, comorbidities, and disability levels.

Conclusion

FEES has become an indispensable tool in the assessment of neurological patients with suspected oropharyngeal dysphagia. By providing objective data on swallowing function, aspiration risk, and the efficacy of protective reflexes, FEES allows clinicians to make timely and informed therapeutic decisions, ultimately improving patient outcomes and reducing complications like aspiration pneumonia. Continued education and interdisciplinary collaboration are vital to maintain high standards in the management of neurogenic dysphagia.

FAQ: FEES for Neurogenic Dysphagia for Students

What does "neurogenic dysphagia" mean?

"Neurogenic dysphagia" refers to difficulty swallowing (dysphagia) that is caused by a problem in the nervous system. This can result from conditions like stroke, Parkinson's disease, or other neurological disorders that affect the brain's ability to coordinate the complex actions required for swallowing.

How does FEES detect "silent aspirations"?

Silent aspirations are dangerous because material enters the trachea (airway) without triggering any protective reflexes like coughing or throat-clearing, making them hard to detect clinically. During a FEES exam, the endoscope directly visualizes the pharynx and larynx as the patient swallows various food consistencies. If food or liquid passes the vocal cords into the trachea without a cough response, it's identified as a silent aspiration.

What are the main advantages of FEES over videofluoroscopy (VFSS)?

FEES offers several key advantages over VFSS, especially for neurological patients. It can be performed at the bedside, making it ideal for immobile or acutely ill patients. It involves no radiation exposure, so it can be repeated frequently for monitoring. FEES also provides excellent direct visualization of the pharynx and larynx, making it highly sensitive to silent aspirations and post-swallowing residues. While VFSS is considered the gold standard for full swallow phase evaluation, FEES is more accessible and repeatable for many clinical situations.

FEES for Neurogenic Dysphagia