Quantitative Analysis of Videostroboscopic Images in Presbylarynges

Abstract

Objective/Hypothesis Age-related dysphonia, or presbylarynges, is often identified as the cause of voice disorders in older individuals. It is a diagnosis of exclusion that typically includes the subjective videostroboscopic findings of vocal fold bowing or atrophy and incomplete glottal closure. We hypothesize that vocal fold bowing correlates directly with glottal gap in patients with presbylarynges and that these characteristics may be quantified objectively using measures obtained from videostroboscopic images. Study Design Retrospective analysis of patient data and prospective analysis of control subjects. Methods The quantitative measures of bowing index and normalized glottal gap, as well as a novel measure, normalized laryngeal outlet, were calculated from the videostroboscopic examinations of 46 patients with presbylarynges and 20 normal control subjects. Results The mean bowing index values from the presbylarynges and control groups differed significantly, although there was overlap of individual values between groups. Bowing index values did not consistently predict normalized glottal gap values. Mean normalized laryngeal outlet values of the patients with presbylarynges were significantly smaller than those of the control group. Conclusions Bowing does not consistently predict the extent of glottal gap. Therefore, other presbylaryngeal changes are probably contributing to incomplete glottal closure, which are not well-visualized stroboscopically, so the finding of bowing is not sufficiently specific to identify presbylarynges. The significantly smaller normalized laryngeal outlet values suggest that this identifies a compensatory strategy for glottal gap to optimize vocal function. This is a novel finding that contrasts with medial ventricular fold squeezing, which is more routinely sought and is typically considered a maladaptive compensatory strategy. Despite the advantages of quantitative stroboscopic measures, limitations in reliability limit their clinical utility.