Parodoxical Vocal Fold Motion (PVFM): Updating Your Nomenclature for Transparency in Documentation

What do the terms paradoxical vocal fold motion, paradoxical vocal cord motion disorder, vocal cord dysfunction, functional airway obstruction, and inducible laryngeal obstruction all have in common?

They are actually all different terms used to describe the same clinical entity!

The Speech-Language Pathology Perspective

For over 20 years, some variation of the term paradoxical vocal fold motion (PVFM) has been used by SLPs to describe the episodic sudden onset of difficulty inhaling (and sometimes exhaling) characterized by inspiratory stridor and a feeling of tightness at the level of the larynx.

The bias toward the term PVFM likely stems from the seminal publication by Barbara Mathers-Schmidt that so elegantly describes the etiologies and details the treatment approach upon which my own work has been based.¹ As Dr. Mathers-Schmidt indicated, the entity was described in the literature as long ago as 1842, but our failure to agree and implement a consistent label has likely slowed our understanding of the disorder.

PVFM as a clinical diagnostic term—and its many iterations—remains problematic because the disorder is not obvious from the name. Additionally, the term PVFM has had a rather broad application for etiologies that include irritant exposure as well as psychogenic and neurogenic etiologies, the latter of which may be better described with different names that reflect the etiology.

The Medical Perspective

Physicians have used many other terms to describe this clinical entity over the years. In 2017, a joint statement from the European Respiratory Society and the European Laryngological Society proposed a new label, inducible laryngeal obstruction (ILO), to replace the long-used term vocal cord dysfunction (VCD).²

The diagnosis of VCD, largely used by pulmonologists, has been problematic for SLPs who treat other disorders of the larynx because the term lacks specificity. From the SLP point of view, VCD could be a catchall term for any of a number of conditions affecting the vocal folds. The term ILO is an improvement over VCD; however, it still lacks a precision that is optimal for this laryngeal condition.

The shift to using ILO has also led to the relatively recent adoption of the diagnostic term of exercise-induced laryngeal obstruction (EILO), a more refined diagnosis for a specific condition with unique therapy approaches.³

Moving Forward

Until SLPs and our physician collaborators can arrive at a consensus for what to call this entity, I propose that we embrace a transitional and transparent approach and collectively refer to this entity as PVFM/ILO.

Some time ago, I shifted from solely using PVFM in my clinical documentation because referring physicians often use the diagnosis of VCD in the referral documentation. In this manner, we can straddle the disciplines of speech-language pathology and pulmonology to acknowledge the value of both labels, signaling to ourselves and our patients that a search of both terms will yield the most comprehensive evidence published in the literature.

Working toward a consensus for the clinical entity that we have frequently described as PVFM is an ongoing process, with changes proposed even since I developed the MedBridge courses on the assessment and treatment of PVFM. Staying current on terminology and embracing a willingness to adopt new terms is critical for discovering the most recent incidence, prevalence, and outcomes data.

Am I ready to assert the adoption of ILO as the accepted term for SLPs? Not quite yet—but I plan to use the combined term PVFM/ILO until we can establish consensus… which might just lead to more specific diagnosis codes than laryngeal spasm.