Abstract
Over-adduction of unaffected vocal fold in unilateral recurrent laryngeal nerve paralysis has been thought to be a compensatory function to decrease glottic incompetence. Using a videorecording of laryngeal fiberstroboscopy, 120 patients with unilateral recurrent laryngeal nerve paralysis were examined and 51 patients had a remarkable over-adduction of unaffected fold during phonation. However, closure of the posterior glottis was imperfect in all patients with over-adduction. The over-adduction was recognized in a number of patients soon after the onset of paralysis. In 13 patients, there was no over-adduction in spite of a marked chink of posterior glottis. Eight of them had clinical findings that suggested an existence of latent disturbance of the recurrent laryngeal nerve on the unaffected side. Examinations of maximum phonation time, mean flow rate, voice range and acoustic analyses revealed that the vocal function was worse in cases with marked over-adduction of the unaffected vocal told than those without over-adduction. The results suggested that over-adduction of unaffected fold is not a compensatory behavior and it tends to occur when the paralyzed fold is fixed away from the midsagittal plane.
