Effect of intralaryngeal muscle synkinesis on perception of voice handicap in patients with unilateral vocal fold paralysis

Abstract

4. Laryngoscope, 127:1628-1632, 2017.

Innervation status in chronic vocal fold paralysis and implications for laryngeal reinnervation

“…The 11% incidence of electrical silence reported in the current series is within what has been reported in the literature . Adductor synkinesis was positive in 30% of the current study cohort, which is comparable to previously reported incidences in the literature . The median time between RLN injury and LEMG was 8.5 months in this study, which represents a reasonable interval to detect reinnervation.…”

“…Therefore, there is likely no need to attempt to restore the innervation by performing LR. To further support this, individuals with electromyographic evidence of adductor synkinesis have been shown to have reduced perception of voice handicap, as measured by the VHI‐10, and are less likely to require permanent vocal fold augmentation compared to those without synkinesis, presumably due to the maintenance of laryngeal muscle tone and therefore medialization of the paralyzed vocal fold . Lastly, it is important to consider the natural history of vocal fold paralysis prior to consideration of permanent vocal fold augmentation.…”

“…previous study further quantifies this definition on LEMG; therefore, adductor synkinesis is determined to be present if the TA‐LCA motor unit potential amplitude ratio during a sniff and during phonation is greater than 0.65 . The presence of adductor synkinesis on LEMG will downgrade a patient's prognosis for vocal fold motion recovery to the poor category but has been found to result in improved voice outcomes . The combination of qualitative information, quantitative analysis, and adductor synkinesis testing has improved the positive predictive value, negative predictive value, and prognostic accuracy of LEMG to 100%, 90%, and 91%, respectively …”

The natural history of recoverable vocal fold paralysis: Implications for kinetics of reinnervation

“…This was deliberate in the study design, because patients were unlikely to undertake the expense and discomfort of LEMG after they started to experience vocal improvement. We also did not feel LEMG was absolutely necessary, because favorable voice outcomes are correlated with electromyographic evidence of synkinetic innervation of the thyroarytenoid/lateral cricoarytenoid muscle complex in patients with persistently immobile, paralyzed VFs . Another limitation was that the parameter estimates could be more robust with a larger sample size.…”

“…We also did not feel LEMG was absolutely necessary, because favorable voice outcomes are correlated with electromyographic evidence of synkinetic innervation of the thyroarytenoid/lateral cricoarytenoid muscle complex in patients with persistently immobile, paralyzed VFs. 33,34 Another limitation was that the parameter estimates could be more robust with a larger sample size. Efforts are underway for further data collection.…”