EILO, VCD, PVFM… Why does this breathing disorder have so many names?

If you or your child has struggled to breathe during sports, you may have heard terms like:

EILO.

VCD.

PVFM.

Inducible laryngeal obstruction.

Vocal cord dysfunction.

Paradoxical vocal fold motion.

You may be asking, “So… which one is it?”

If you’re confused, you’re not alone.

The terminology describing laryngeal breathing disorders has changed considerably throughout the years. In fact, researchers have identified over 40 different terms used to describe the condition before an international consensus terminology was developed.

Let me help break it down.

First, what is happening?

The larynx, commonly called the voice box, sits at the top of the airway.

During breathing, the larynx remains open to allow air to flow freely in and out of the lungs.

However, sometimes the larynx or structures surrounding it narrow or close in response to a particular trigger.

When the narrowing is episodic and causes breathing difficulty, the current umbrella term is:

Inducible Laryngeal Obstruction — or ILO

ILO describes episodes in which the larynx narrows in response to a trigger. The trigger may vary person to person, and a person may have more than one trigger.

Triggers may include:

• Environmental irritants
• Strong odors
• Stress
• Changes in temperature
• Exercise
• Other stimulants

It is important to know that ILO is an umbrella term. It is embedded with phenotypes/subtypes, such as irritant ILO and EILO.

So what is EILO?

EILO refers to exercise-induced laryngeal obstruction. In other words, exercise is the trigger.

EILO is particularly relevant to athletes because symptoms often occur during high-intensity exercise and include symptoms such as breathlessness, difficulty getting air in, noisy and high-pitched breathing sounds, and throat tightness.

These symptoms often improve quickly once exercise stops.

Okay, where did VCD come from?

You may have also heard the term VCD — or vocal cord dysfunction.

VCD was a commonly used term to describe inappropriate vocal fold closure associated with breathing difficulty.

It is still widely used by patients, parents, medical professionals, and online resources.

But there is a problem with this term. The vocal cords aren’t always the only structures involved.

For example, obstruction can occur at the level of the vocal folds (glottis), the structures above the vocal folds (supraglottis), or both.

Therefore, vocal cord dysfunction doesn’t always accurately describe what is happening anatomically.

That’s one of the reasons why the field moved toward more descriptive terminology.

What about PVFM?

PVFM stands for paradoxical vocal fold motion.

This term describes inappropriate or paradoxical movement of the vocal folds when breathing.

Like VCD, PVFM has been commonly used in the literature and in clinical practice.

Its terminology also focuses on the vocal folds, whereas ILO provides a broader framework for describing inducible obstruction of the laryngeal airway.

Does that mean VCD and PVFM are wrong?

Not necessarily. They are still terms you might encounter, but are considered older terms. They can be useful when describing what was previously observed or documented.

The challenge with these terms is that they have been used inconsistently.

Two clinicians can use different terms to describe similar symptoms. Others may use the same terms to describe somewhat different findings.

The international consensus terminology introduced ILO as an umbrella term to create a more consistent way of describing these conditions.

What does this mean for parents?

Because your search history might look like this:

You search Google for exercise-induced breathing difficulty for your child.

You find:

Vocal cord dysfunction

Then another website says:

PVFM.

Your child’s medical record says:

EILO.

It feels like everyone is talking about a different condition when they may not be.

The terminology has evolved, but the older terms remain commonly used.

Knowing the different names can actually help make it easier to find accurate information and appropriate care.

What term should you search for?

If your child experiences breathing difficulty during exercise, I’d recommend starting with exercise-induced laryngeal obstruction (EILO).

Common search terms used by parents include:

• EILO treatment
• EILO in athletes
• EILO in children
• Speech therapy for EILO
• Exercise-induced vocal cord dysfunction
• Paradoxical vocal fold motion

Searching the older terminology may remain useful.

Keep in mind that the name may have changed, but the experience hasn’t.

If you have been told your child has VCD, PVFM, or EILO, you may have wondered why different people use different terminology.

You’re not imagining an inconsistency.

The field has evolved, the terminology has become more specific as researchers and clinicians have learned more about the different ways the larynx can contribute to breathing difficulty.

Today, ILO is the broader umbrella term, while EILO refers specifically to laryngeal obstruction triggered by exercise.

That doesn’t mean the older terms are going to disappear overnight.

Sometimes finding the right information and support requires knowing all of the names.

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At Functional Airway Lab, I specialize in breathing retraining for adolescents and adults with EILO.

If you are here to better understand your child’s exercise-related breathing symptoms, please do not hesitate to reach out.

My goal is to make this make a little more sense.