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Vocal cord dysfunction (VCD) is also known as inducible laryngeal obstruction (ILO). It is also called paradoxical vocal fold motion (PVFM).

If VCD symptoms happen only during exercise, then it is called exercise-induced laryngeal obstruction (EILO). This problem causes shortness of breath which can be very severe.

VCD/ILO is a serious condition. It can cause extreme changes in quality of life. VCD/ILO is frequently misdiagnosed as asthma.

Normal and Abnormal Vocal Cord Function

To understand VCD/ILO, it is helpful to understand how the vocal cords function. The vocal cords are located at the top of the windpipe (trachea). They vibrate to produce noise and voice. Breathing causes the vocal cords to open. This allows air to flow through the windpipe (trachea) and into the lungs. During episodes of VCD/ILO, the vocal cords partly or completely tighten. This causes shortness of breath.

Vocal cord dysfunction is different from vocal cord paralysis.


History of VCD & EILO

VCD/ILO was discovered relatively recently. Some descriptions of possible cases first appeared in medical literature in 1842 and then again in 1951. Both times it was inaccurately characterized as having self-created symptoms.

In 1983, a group of people who were said to have "uncontrolled asthma" were evaluated  at National Jewish Health. A team of medical professionals, including pulmonologists, otolaryngologists, psychiatrists and speech-language pathologists provided the evaluation. They accurately identified the condition and provided treatment for what we now know as VCD. Their findings were published in the New England Journal of Medicine in 1983.

People with symptoms limited to exercise were described in the years that followed. Since the 1980s, we have come to realize that they do not share all of the features seen in the first group described in 1983.