Ej. Damrose et al., Lack of evoked laryngeal electromyography response in patients with a clinical diagnosis of vocal cord paralysis, ANN OTOL RH, 110(9), 2001, pp. 815-819
There has been recent debate about whether patients with vocal cord immobil
ity have a neurologic paralysis or whether synkinesis, the misdirection of
axons to competing laryngeal muscles, is responsible for the lack of volunt
ary vocal cord motion. This issue was studied in 15 patients with vocal cor
d paralysis who underwent laryngeal reinnervation. Evoked electromyography
was performed with a surface electrode endotracheal tube. The recurrent lar
yngeal nerve (RLN) was identified and stimulated with constant current. Of
the 15 patients, only 1 produced a compound muscle action potential upon ne
rve stimulation. The remaining 14 patients had no evoked response during RL
N stimulation. A control group of 8 patients with normal vocal cord mobilit
y was studied, and each had a normal evoked electromyography response after
RLN stimulation. These results support the assertion that patients who req
uire treatment for vocal cord paralysis do not have synkinesis produced by
RLN reinnervation.