Endoscopic Assessment of Vocal Fold Movements during Cough

Abstract

Little is known about the function of the true vocal folds (TVFs) during cough. The objective of this study was to determine the reliability of measuring TVF movements during cough and to obtain preliminary normative data for these measures. Sequential glottal angles associated with TVF adduction and abduction across the phases of cough were analyzed from laryngeal videoendoscopy records of 38 young healthy individuals. The intraobserver and interobserver reliability of 3 experienced measurers was high (intraclass correlation of at least 0.97) for measuring sequential and maximum glottal angles. The TVF abduction velocity during expulsion was significantly higher than the precompression adduction velocity (p = 0.002), but there were no significant differences in maximum angle. No statistically significant differences were seen in maximum TVF angle and velocity when they were compared between the sexes and between the levels of cough strength. True vocal fold closure following expulsion occurred in 42% of soft coughs and in 57% of moderate to hard coughs. The TVF abduction angles during cough can be reliably measured from laryngeal videoendoscopy in young healthy individuals. The TVF movements are faster for expulsion abduction than for precompression adduction, but the extents of abduction are similar. To validly determine the cough phase duration, simultaneous measures of airflow are needed.