Vocal Fold Paresis: An Evolving Clinical Concept

Abstract

Neurogenic compromise of vocal fold function exists along a continuum encompassing variable degrees and patterns of partial denervation (paresis). Not abundantly recognized until recently, vocal fold paresis is probably a significant source of vocal disability, especially among cases that have eluded straightforward diagnosis. It presents with symptoms of glottic insufficiency, and probably follows a clinical course analogous to that of paralysis. As a result of preserved gross mobility, paresis can be difficult to diagnose and distinguish from innocent asymmetries of laryngeal motion. Both laryngoscopy/ stroboscopy and electromyography are useful in diagnosis despite both of them having important limitations. Because of these, trials of treatment are uniquely useful in vocal fold paresis. Significant disagreement persists regarding incidence, causes, signs, and association with other diseases. Treatment consists of medialization and/or augmentation procedures that do not compromise remaining neural function.

Vocal fold paresis

“…Patients may state that they feel that baseline speech or singing is simply more effortful despite achieving what appear to be adequate tone, pitch, and timbre. Difficulty vocalizing over distances or outdoors, fading over prolonged use, or even difficulty in rapidly changing pitch may all serve as clues of a paretic vocal fold [1].…”

“…All of these limit the ability to assess the impact of significant vocal fold asymmetrical movements or identification of subtle movement impairments. An obvious paralysis or paresis can be readily identified as gross vocal fold hypomobility or glottic insufficiency as they are the most common findings [1]. Most authors identify vocal fold paresis in the literature utilizing visual clues such as vocal…”

“…fold bowing (especially in a patient <50 years old), decreased abduction or adduction, axial tilt of the larynx, vertical height mismatch, phase lag, and asymmetric mucosal wave amplitudes and frequencies [1,3,4…”

“…In many practices, the needle is introduced by a laryngologist who is more familiar with the anatomy and then interpreted by the neurologist. The presence of fibrillation potentials, positive sharp waves, polyphasic motor action potentials, and a neuropathic interference pattern are pathognomonic for neurological injury and clearly point to a diagnosis of paralysis or paresis [1,3,13,23]. However in paresis, the LEMG signs may not always be clear cut.…”

“…However, the term 'paresis' for the purposes of this discussion denotes the preservation of some degree of mobility, thereby making it a discrete clinical entity from paralysis [1,3]. As such, the diagnosis of paresis becomes one that is attained either on visual inspection (endoscopy or stroboscopy) or in conjunction with neurodiagnostic testing [laryngeal electromyography (LEMG)] [4,5 && ,6 & ] (Fig.…”