Inducible Laryngeal Obstruction (ILO), also known as Vocal Cord Dysfunction (VCD), is a condition in which the vocal cords (also called vocal folds) involuntarily close or constrict during breathing, leading to obstruction of the upper airway. This obstruction often occurs during physical exertion, stress, or even at rest, and it results in symptoms similar to asthma, such as difficulty breathing, wheezing, coughing, and a feeling of tightness in the throat.

However, unlike asthma, ILO does not involve the lower airways, and it is not caused by inflammation or narrowing of the bronchi (airways in the lungs). The condition is primarily a dysfunction in the vocal cords, which fail to open properly during inhalation, causing airflow obstruction.

Key Features of ILO:

1. Symptoms:
   
   • Shortness of breath (especially during exertion)
   • Wheezing or stridor (high-pitched sound when breathing)
   • A feeling of throat tightness or suffocation
   • Coughing
   • Hoarseness or voice changes
   • Difficulty inhaling, with some patients feeling they can’t “catch their breath”
2. Triggers:
   • Exercise or physical activity (exercise-induced ILO)
   • Stress, anxiety, or emotional distress
   • Strong smells, allergens, or irritants (e.g., smoke)
   • Cold air
   • In some cases, the symptoms can occur during sleep or at rest
3. Cause: The exact cause of ILO is not always clear, but it is believed to involve a combination of:
   • Irritants: Reflux, post-nasal drip and allergies can serve as triggered for ILO.
   • Muscular dysfunction of the vocal cords, where they close inappropriately during inhalation.
   • Neurological factors: Abnormal signaling in the brain or nervous system can lead to improper vocal cord movement.
   • Psychological factors: Stress, anxiety, and emotional factors can contribute to or trigger episodes of ILO.
   • Multifactorial: a combination of all factors can create the “perfect storm” where ILO may occur.

4. Diagnosis:
   • Laryngoscopy: A procedure where a flexible tube with a camera is inserted into the throat to visualize the vocal cords in action.
   • Pulmonary function tests: These may be done to rule out asthma or other respiratory conditions, as ILO can mimic asthma symptoms.
   • Exercise challenge tests: To see if symptoms appear during physical activity.
   • Voice therapy: At South Tampa Voice Therapy, speech-language pathologists assist with the diagnosis and treatment of ILO. 
5. Treatment:
   
   • Breathing techniques: Learning specific techniques to control breath and avoid constriction of the vocal cords (e.g., high resistance breathing, diaphragmatic breathing).
   • Speech therapy: Voice training can help patients learn how to keep the vocal cords open during breathing, especially during exertion.
   • Relaxation and stress management: Techniques like meditation or cognitive-behavioral therapy (CBT) can be helpful for reducing anxiety and stress, which can trigger episodes.
   • Medications: In some cases, medications to reduce inflammation (e.g., inhalers) may be prescribed if there is an overlap with other conditions, but they are not the primary treatment for ILO.

Distinguishing from Asthma:

One of the key challenges in diagnosing ILO is that its symptoms often overlap with asthma, such as wheezing and shortness of breath. However, asthma typically involves inflammation and constriction of the airways in the lungs (lower airways), which is not the case with ILO. Testing like laryngoscopy helps differentiate the two.

In summary, Inducible Laryngeal Obstruction is a functional disorder of the vocal cords that can cause significant breathing difficulties, but it is treatable with proper diagnosis and management strategies.

About the Author: Cara Bryan, MA, CCC-SLP, is a speech-language pathologist and voice specialist in Tampa, Florida. She evaluates and rehabilitates voice, communication difficulties, cognitive disorders, upper airway disorders and swallowing difficulties at her private practice, South Tampa Voice Therapy. Cara is a classically trained soprano with a major in vocal performance from University of North Carolina at Chapel Hill. She has spent her career working in medical speech pathology in the hospital setting, ENT offices, and now in private practice. Cara mentors on voice, upper airway, business and private practice through www.southtampavoicetherapy.com. You can follow her on Instagram and FaceBook.