Consideration of vocal fold position in unilateral vocal fold paralyses

Abstract

The objective of this study was to improve the evaluation of unilateral vocal fold paralyses (uVFP) by means of an area measurement of the glottic plane, which describes the position of the paralysed vocal fold. The area measurements were related to electromyographic findings and clinical outcome (recovery, voice quality). In 56 patients (33 women and 23 men), uVFP were confirmed by endolaryngeal electromyography (EMG) of the paralysed vocal fold and cricothyroid muscles (CT). The EMG response was classified on a 4-point scale (from 0 to 3). Vocal fold position was divided into 'paramedian' and 'intermediate' and additionally quantified by measurement of the glottic area. An 'area quotient' (AQ) was calculated and related to the EMG findings and clinical outcome. Voice qualities were objectified regarding their additive noise (breathiness) and irregularity (roughness) using the 'Göttingen Hoarseness Diagram'. The majority of uVFP was due to iatrogenic lesions. The AQ of classically graduated 'paramedian' and 'intermediate' vocal fold positions was significantly different but did not correlate with objective voice quality values. There were no significant correlations regarding EMG findings, duration or recovery from paralyses. Laryngeal EMG remains the gold standard for verifying uVFP. But EMG did not correlate significantly with AQ or functional outcome of uVFP. The measurement of an AQ is suitable for obtaining continuous data describing the position of paralysed vocal folds beyond the terms 'paramedian' or 'intermediate' and provides the basis for clinical evaluations of diagnostic tools and therapeutic interventions.