Glottographic phase difference in recurrent nerve paralysis

Phase measures with simultaneously recorded electroglottography (EGG) and p hotoglottography (PGG) signals have been studied in canine models and found to be sensitive to the effect of recurrent laryngeal nerve (RLN) paralysis on vocal fold vibration. This study examined the usefulness of this type o f measure in clinical application. The combined glottographic signals were obtained from 5 men with a diagnosis of unilateral RLN paralysis and 5 age- matched controls. In the patient group, EGG waveforms were found to have a consistent phase delay in relation to PGG. A measure of the overall glottog raphic phase difference (GPD) was found to significantly distinguish the co ntrol group (mean GPD = 0.2371 ms) from the patient group (mean GPD = -0.27 65 ms). A validity analysis performed on 19 subjects with or without unilat eral RLN paralysis confirmed that the GPD test had a relatively high effici ency (91.7%) in detecting unilateral RLN paralysis in the male population.