The Study of Laryngoscopic and Autonomic Patterns in Exercise-Induced Laryngeal Obstruction

Abstract

Objectives: (1) Identify laryngeal patterns axiomatic to exercise-induced laryngeal obstruction (EILO) and (2) investigate the role of autonomic function in EILO.

Methods: Twenty-seven athletic adolescents (13 EILO, 14 control) underwent laryngoscopy at rest and exercise. Glottal configurations, supraglottic dynamics, systolic blood pressure responses, and heart rate recovery were compared between conditions and groups.

Results: Inspiratory glottal angles were smaller in the EILO group than the control group with exercise. However, group differences were not statistically significant ( P > .05), likely due to high variability of laryngeal responses in the EILO group. Expiratory glottal patterns showed statistically greater abductory responses to exercise in the control group ( P = .001) but not the EILO group ( P > .05). Arytenoid prolapse occurred variably in both groups. Systolic blood pressure responses to exercise were higher in the control group, and heart rate recovery was faster in the EILO group. However, no significant differences were seen between the 2 groups on either autonomic parameter ( P > .05).

Conclusions: "Paradoxical" inspiratory and blunted expiratory vocal fold pattern responses to exercise best characterize EILO. Group differences were only seen with exercise challenge, thus highlighting the utility of provocation and control groups to identify EILO.

Keywords: airway disorders; endoscopy; exercise; laryngeal physiology; laryngology; miscellaneous; otolaryngology; vocal cord dysfunction.

Figure 1.

Anterior glottal angle measurements. Raters first identified the medial edge of each vocal fold. Raters then placed a coordinate at the medial tip of the right vocal process with a single click of the mouse, followed by double clicking the mouse at the vertex of the anterior commissure on the ipsilateral side (or slightly past the commissure) to create a line that followed the medial edge of the superior vocal fold. The same patterns were conducted on the left vocal fold, creating crosshairs at the anterior commissure. Anterior glottal angles were calculated from the crosshairs and automatically populated into an Excel spreadsheet using the customized MATLAB program.

Figure 2.

Anterior glottal angle (inspire and expire) configurations. The figure represents both an average of 2 images taken within the same condition and group averages. Glottal angles at baseline were similar between the 2 groups. In contrast, robust group differences were seen with exercise challenge. Participants in the exercise-induced laryngeal obstruction (EILO) group showed decreased inspiratory glottal configurations with exercise (ie, paradoxical vocal fold motion). Although expiratory glottal angles from rest to exercise challenge increased in both groups, angles were larger in the control group. Reduced abductory patterns during the expiratory phase in the EILO group, compared to the control group, may indicate a sluggish expiratory response to exercise.

Figure 3.

(A) Anterior glottal angle differences between 2 images taken within the same condition (baseline exhale, baseline inhale, exercise exhale, exercise inhale). This figure represents the level of variability in angle responses that occurred within the same condition. Specifically, the majority of angle differences were within 15° of each other. However, greater inspiratory differences were seen in 2 participants in the exercise-induced laryngeal obstruction (EILO) during strenuous exercise (outliers: E01 and E07). (B) Post hoc analysis of all angles within the same condition for the 2 individuals showed high variability in inspiratory laryngeal responses across the same condition (represented by line graphs). However, this variability was not present in all individuals in the EILO group; see line graph for participant E10 for example. Angles measured across the same condition were also less variable in the control group; see C06 and C10 for comparison.

Figure 4.

Parasympathetic and sympathetic autonomic responses between the 2 athletic groups, determined by (A) magnitude of change in systolic blood pressure from rest to maximum exertion and (B) 2-minute heart rate recovery (2-HRR). Changes in pressures were slightly higher in the control group than exercise-induced laryngeal obstruction (EILO) group while 2-HRR was slightly faster in the EILO group, compared to the control group. Although group differences were not significant, trends in these patterns might suggest sluggish sympathetic responses to exercise or heightened parasympathetic activity, at least in some individuals with EILO. Therefore, the role of autonomic responses in EILO warrants future investigations.