High-Speed Kymography and Unilateral Paralyzed Vocal Fold: Case Reports Treated with Calcium Hydroxyapatite
Introduction: The development of methods contributes in assessment and treatment of voice.
Objective: To report changes in the phase time of the glottal cycle of patients with unilateral paralyzed vocal fold treated with calcium hydroxyapatite (CaHa), through high-speed kymography.
Report: Two female patients (67 year olds) participated in this study. Both patients showed diagnosis of unilateral paralyzed right vocal fold and underwent CaHa augmentation. The procedure was performed by a laryngology surgeon under general anesthesia. Vocal-fold vibrations were recorded with a high-speed camera (4,000 Hz, 256 × 256 pixels) before CaHa augmentation and a month after the treatment. The images were processed in order to get high-speed kymography. The closed (CPh), open (OPh), closing (cPh), and opening (oPh) phases were extracted in milliseconds. Fundamental frequencies (F0) were calculated by using the total time of the glottal cycle. The first patient showed an increase of CPh (preinjection: 1.25 ms; postinjection: 2.00 ms) and cPh (before: 1.25 ms; postinjection: 1.38 ms). There was a decrease of oPh (preinjection: 1.13 ms; postinjection: 1.00 ms) and F0 (preinjection: 276 Hz; postinjection: 228 Hz). OPh maintained the same values (preinjection and postinjection 2.38 ms). The second patient showed an increase of CPh (preinjection: 2.12 ms; postinjection: 2.38 ms) and F0 (preinjection: 152 Hz; postinjection: 170 Hz); there was a decrease of OPh (preinjection: 4.48 ms; postinjection: 3.07 ms), oPh (preinjection: 2.36 ms; postinjection: 1.42 ms) and cPh (preinjection: 2.12 ms; postinjection: 1.65 ms).
Conclusion: The glottal cycle of both patients showed a longer closed phase. This change is due to the CaHa augmentation and medialization of the paralyzed vocal fold.