Evaluation of vocal cords’ vibratory function using laryngeal videostroboscopy parameters in laryngopharyngeal reflux disease

Background: Reflux of gastric content into the upper aerodigestive tract may cause microtrauma to the vocal cords and lead to many vocal cord pathologies. Laryngeal videostroboscopy (LVS) is a modality to evaluate the vibratory function of vocal cords using 10 parameters such as vibratory amplitude, mucosal wave, vibratory behavior, supraglottic activity, glottal closure, vertical level, free edge contour, phase closure, phase symmetry, and regularity. These parameters have an important role in early diagnosis and defining the pathophysiology of vocal cord abnormalities in laryngopharyngeal reflux (LPR) patients. Objective: The purpose of the study was to determine which LVS parameters can be used as an indicator to identify the difference in vocal cord damage in LPR compared with the normal subject group. Materials and Methods: This study involved 61 patients who underwent LVS in Cipto Mangunkusumo Hospital. Seven patients were excluded, resulting in a total of 54 patients with 27 patients in each group. An analytic comparative cross-sectional study was conducted to compare LVS parameters between two groups. The author also conducted correlation analysis to find the relationship among each LVS parameter and the relationship between LVS parameters with grade of dysphonia. Result: Of the 27 patients in the LPR group, only 5 (18.5%) patients have dysphonia. Eight out of 10 LVS parameters were significantly different between LPR group and normal control group, that is, vibratory amplitude ( P < 0.001), mucosal wave ( P < 0.001), vibratory behavior ( P < 0.001), supraglottic activity (SGA; P < 0.001), free edge contour ( P = 0.003), phase symmetry ( P < 0.001), regularity ( P = 0.001), and phase closure ( P = 0.001). Of these eight parameters, SGA was the most important parameter in understanding the vocal cord pathology in LPR, as much as 40.3%, with an R 2 of 0.776. There was significant correlation among each parameter in the LPR group, such as amplitude, mucosal wave, SGA, and vibratory behavior ( P < 0.001). Grade of dysphonia only has a correlation with right and left mucosal wave with P values of 0.028 and 0.017, respectively, and no correlation with other parameters. Conclusion: Comprehensively, 8 out of 10 LVS parameters can be used as a tool to evaluate the vocal cord damage in LPR. Furthermore, those parameters may explain the association of vocal cord abnormalities due to reflux.