Flexible Endoscopic Evaluation of Swallowing (FEES)

Flexible endoscopic evaluation of swallowing (FEES), sometimes also called fiber-optic endoscopic evaluation of swallowing, is a portable procedure that may be completed in outpatient clinic space or at bedside by passing an endoscope transnasally (Langmore et al., 1988). FEES may be conducted by a speech-language pathologist (SLP), a physician, or collaboratively together. FEES may be recommended regardless of setting (e.g., hospital, skilled nursing facility). FEES is used without concerns of radiation exposure and can be used within therapeutic contexts and for diagnostic therapy to assess current progress and effectiveness of therapy. If there are clinical indications for a laryngoscopy evaluation (e.g., hoarse voice, pain on swallowing), the SLP may consider consulting with a physician regarding a referral to an otolaryngologist to rule out the possibility of disease in the nasal, pharyngeal, or laryngeal region.

In addition to the general indications for instrumental evaluation, the following indications are specific to FEES:

  • sensitivity to increased difficulty with swallowing over the course of a bottle feeding, breastfeeding, or meal, secondary to suspected fatigue
  • sensitivity to velum function for hypernasality and/or suspected nasal regurgitation
  • need for visualization of the hypopharynx/larynx for biofeedback and/or rehabilitation
  • need to assess vocal fold dynamics or the laryngeal adductor reflex (LAR) related to swallow function (see below)
  • documented pharyngeal dysphagia on a videofluoroscopic swallowing study that can be retested with endoscopy to
    • monitor progress,
    • directly assess pharyngeal and laryngeal anatomy, and/or
    • limit radiation exposure
  • suspected or observed difficulty with swallowing saliva/oral secretions
  • inability to tolerate contrast media (e.g., barium, iohexol) due to allergy or aversion
  • concerns or safety issues associated with radiation exposure (e.g., pregnancy)
  • patients’ inability (e.g., patients on ventilators, patients on extracorporeal membrane oxygenation [ECMO]) to leave the bedside because of mobility and/or postural deficits
  • difficulties with obstructed fluoroscopic viewing (e.g., patients wearing a halo, patients wearing a cervical collar)
  • limited access to radiologic equipment

In addition to the contraindications for all instrumental evaluations, the following contraindications are specific to FEES:

  • severe agitation and/or inability to cooperate with the examination
  • severe movement disorders that interfere with safe administration
  • severe bleeding disorders and/or recent severe epistaxis (nosebleed)
  • history of recent trauma to the nasal cavity or surrounding tissue and structures secondary to surgery or injury
  • bilateral obstruction of the nasal passages


Procedures for FEES vary across settings and across clinicians. Clinicians should follow guidelines from their facility and licensing body regarding FEES procedures.

Prior to bolus delivery, the SLP may

  • educate the patient and/or caregiver regarding FEES procedures and rationale for the examination;
  • position the patient consistent with the patient’s typical eating posture (e.g., upright, reclined);
  • provide a topical anesthetic if appropriate (see below for further information regarding anesthetics);
  • select the appropriate endoscope type and size;
  • insert the scope;
  • identify anatomical landmarks and any abnormalities;
  • administer flexible endoscopic evaluation of swallowing with sensory testing (FEESST), if indicated, to determine laryngeal adductor reflex (LAR) sensitivity and vocal fold dynamics; and
  • assess basic movement abilities of anatomical structures through specific maneuvers (e.g., have the patient perform the Valsalva maneuver to evaluate vocal fold closure, ask the patient to say words with no nasal phoneme stimuli to assess velopharyngeal closure).

During or following bolus delivery, the SLP may

  • identify abnormal swallow function and the subsequent effect on laryngeal penetration, residue, sensory awareness, and effectiveness of the patient’s response to laryngeal penetration and/or residue—aspiration is inferred based on patient response and/or observation of material below the vocal folds after the swallow;
  • monitor for adverse reactions to the examination and respond appropriately;
  • assess the influence of fatigue on pharyngeal swallow function over multiple trials;
  • assess initiation of swallow and timing of structural movement in response to the bolus;
  • identify any residue remaining in the pharyngeal or laryngeal cavities after the swallow; and
  • introduce strategies to minimize and/or eliminate aspiration.

Typically, food is minimally colored via dye to assist in assessing pharyngeal-physiologic safety and inefficiency issues, including secretion management, pharyngeal residue, and aspiration.

The SLP can test sensation in the hypopharynx and larynx directly with a modification of the FEES procedure. FEESST requires a two-channel scope and uses pulses of air to assess sensory perception of the larynx and to monitor the LAR. The LAR is characterized by a brief closure of the true vocal folds. FEESST uses a pressure- and duration-calibrated air puff, delivered anterior to the arytenoids along the aryepiglottic folds to test the intensity level at which the LAR is elicited.

SLPs do not require special certification from ASHA or any other entity to perform instrumental assessments. SLPs with appropriate training and competence in performing FEES are qualified to use this procedure independently for the purpose of assessing swallow function and related functions of structures within the aerodigestive tract. Please refer to ASHA's code of ethics for further information regarding decision making related to professional conduct. ASHA does not require the presence of a physician for an SLP to perform FEES; however, there may be state-specific requirements and/or regulations. SLPs should be aware of state laws, facility policies, and third-party payer requirements related to the presence of a physician during FEES and should also be aware of any scope-of-practice requirements related to endoscopy. See ASHA’s page on state instrumental assessment requirements. Physicians may also be involved in functional swallowing evaluation and/or may be present to assess the integrity of laryngeal and pharyngeal structures in order to provide a medical diagnosis.

Limitations of FEES

The FEES procedure includes the following limitations:

  • Inability to visualize the oral or the esophageal phase of swallowing.
  • Limited ability to visualize the pharyngeal phase. However, a clinician may be able to visualize the initiation of pharyngeal structural movements through
    • the pharyngeal squeeze,
    • superior movement, and/or
    • epiglottis inversion.
  • “White-out”—passage of the bolus and movement of the pharyngeal structures cannot be observed during the swallow because of reflected light from pharyngeal and laryngeal tissues into the endoscope.
  • Inability, by some patients, to tolerate the procedure due to discomfort and/or medical conditions.

Precautions and Safety Considerations

The patient may, on rare occasions, experience adverse effects when undergoing FEES (Langmore, 2001). These may include but are not limited to

  • discomfort,
  • vomiting,
  • epistaxis (nosebleed),
  • mucosal perforation,
  • an allergic reaction or hypersensitivity to topical anesthesia or nasal spray, and
  • laryngospasm.

Clinicians should be well trained in the signs and symptoms of adverse reactions, know their facility’s plan for response and intervention to such reactions, and be ready to take appropriate actions if they occur. It is advisable to have suction equipment and personnel trained in the use of such equipment if available. Use of a cardiac monitor may be warranted for patients with significant pulmonary disease, cardiac arrhythmia, seizure disorders, or other medical conditions. The possible risks for localized nasal trauma and bleeding are considered. Special care is taken with use of topical anesthesia in medically fragile infants and children. Clinicians are encouraged to consult with the child’s medical team prior to using anesthesia with these children.

SLPs follow universal precautions and facility procedures for infection control (e.g., adequate disinfection of equipment). Decontamination, cleaning, disinfection, and sterilization of multiple-use equipment before reuse are carried out according to facility-specific infection control policies and services and according to manufacturers’ instructions. All equipment is used and maintained in accordance with the manufacturers’ specifications. For further information on infection control, please visit ASHA’s page on infection control resources for audiologists and speech-language pathologists.

Please also see ASHA’s pages on coronavirus/COVID-19 updates as well as aerosol generating procedures.



Langmore, S. E. (2001). Endoscopic evaluation and treatment of swallowing disorders. Thieme.

Langmore, S. E., Schatz, K., & Olsen, N. (1988). Fiberoptic endoscopic examination of swallowing safety: A new procedure. Dysphagia, 2(4), 216–219. https://doi.org/10.1007/BF02414429

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