Vibration of the vocal cords in some pathological conditions

Abstract

Vibratory mede of some pathological vocal cords was investigated with a use of ultrahigh-speed photography. The most frequent abnormalities in vibration in the cases of unilateral recurrent laryngeal nerve paralysis are an incomplete glottic closure, asymmetric movements of the two cords, and a decrease in or absence of mucosal wave on the affected cord. In the cases of vocal cord polyp, a relatively soft mass, the vibrating abnormal mass causes an incomplete glottic closure, a decrease in amplitude of vibration, and phase differences between movements of the affected portion and those of the nonaffected. A cancerous lesion, which always has a great stiffness, results in absence of vibration of the affected area and a hindrance to the movements of the nonaffected cord.