REFERENCE · DIAGNOSTIC TECHNIQUE

Laryngoscopy and Upper-Airway Assessment

Clinician-focused educational reference; assessment requires appropriate training, consent and an individual safety plan.

Purpose and Suitability
Anatomy and Physiology
Preparation and Safety
Performing the Assessment
Interpreting Findings
Explaining the Result
Evidence and Limitations
Media and Accessibility
Research and Sources

Purpose and Suitability

Investigate suspected inducible laryngeal obstruction (ILO) and structural alternatives in a specialist airway service. This is an examination of the larynx, not a general test for neurological FND.

Inducible laryngeal obstruction: Episodic narrowing at the voice box associated with breathing difficulty. Laryngoscopy: Viewing the larynx with a scope.

The person’s typical symptoms and the visible finding must be related. An examination between episodes can miss the relevant narrowing. [1]

Anatomy and Physiology

The larynx is the voice box at the airway entrance. The examiner identifies whether narrowing occurs at the vocal folds or above them, and during which part of breathing.

Glottic: At the vocal folds. Supraglottic: Above the vocal folds.

Different sites and patterns should be described rather than collapsed into a cough label. The 2023 consensus addresses these clinical descriptions. [2]

Preparation and Safety

The qualified team explains scope insertion, expected sensations, recording, alternatives and stopping. Check current airway stability, relevant prior investigations and the person’s communication and access needs. Agree a stop signal usable when speech is difficult.

Provocation requires a defined clinical question, suitable monitoring and an individual risk assessment. A teaching video is never a reason to provoke breathing difficulty. Exercise or irritant challenges are not home tests. Maintain the person’s established emergency and coexisting respiratory care plan.

Performing the Assessment

Laryngoscopy during typical airway symptoms

Visualization can document inducible laryngeal narrowing. Normal examination between episodes may miss it. This supports inducible laryngeal obstruction when the pattern matches; it does not by itself establish a neurological FND diagnosis. [1]

The specialist documents whether the episode was typical, the timing and site of narrowing, the breathing phase and the adequacy of the view. Record an unsuccessful or incomplete symptom sample explicitly.

Continuous laryngoscopy during exercise

For exertional symptoms, a specialist may observe the larynx through a monitored exercise challenge. The test addresses exercise-induced laryngeal obstruction, not FND in general. Suitability and safety determine whether provocation is justified. [1]

Continuous laryngoscopy during exercise (CLE): Keeping the larynx in view through a supervised exercise assessment.

Choose the clinical protocol through the responsible service. Document why the chosen activity is relevant and whether it reproduced the usual problem; this page does not prescribe exercise intensity or a challenge agent.

Interpreting Findings

Concordant finding: Relevant laryngeal narrowing during typical symptoms supports ILO. The 2023 Delphi panel endorsed provoked laryngoscopy and proposed at least 50% inspiratory closure or Maat grade at least 2 as abnormal. These are specialist consensus thresholds, not a self-scoring tool. [2]

Normal or inconclusive sample: Record whether typical symptoms actually occurred; a symptom-free examination cannot settle an intermittent complaint. Asthma and ILO can coexist. [1]

The result does not measure everyday activity tolerance or establish that all breathlessness has the same cause. Ask which situations remain unexplained and agree who will follow them up.

Explaining the Result

Authored example, not a patient quotation:

“This examination shows what your voice box did during the symptoms we captured. I will explain whether that supports ILO and what the test could not answer. We still need to account for any other breathing condition and the activities you find difficult.”

If the episode was not typical, say so in the explanation and report.

Evidence and Limitations

The 2023 modified Delphi study involved 47 experts completing two rounds; 130 of 200 statements reached consensus. It established agreement, not sensitivity or specificity against an independent reference standard. The abstract and bibliographic record were reviewed; a full-text methodological appraisal remains pending. [2]

The 2020 UK statement addressed pandemic restrictions. Its provisional pathways should not be presented as current permission to replace laryngoscopy routinely. [1]

Media and Accessibility

Use a labelled anatomy diagram or an existing, specifically consented and de-identified clinical recording. Show the phase of breathing and identify what is visible without implying that the clip represents every episode.

Provide still-image alternatives, descriptive captions and a transcript. Consent to a clinical scope recording does not automatically authorize public teaching use.

Research and Sources

The sources concern ILO assessment. They do not validate ILO as a universal FND sign. Consent, sampling and daily-impact prompts are editorial safeguards.

Citation	Full citation
[1]	Haines J, Esposito K, Slinger C, et al. UK consensus statement on the diagnosis of inducible laryngeal obstruction in light of the COVID-19 pandemic. Clinical and experimental allergy : journal of the British Society for Allergy and Clinical Immunology. 2020;50(12):1287-1293. DOI. PMID: 33034142. FND-CIT-0147.
[2]	Leong P, Vertigan AE, Hew M, et al. Diagnosis of vocal cord dysfunction/inducible laryngeal obstruction: An International Delphi Consensus Study. Journal of Allergy and Clinical Immunology. 2023;152(4):899–906. DOI. FND-CIT-0255.

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