Perceptual Clinical Features in Exercise-Induced Laryngeal Obstruction (EILO): Toward Improved Diagnostic Approaches.

introductionAthletes with exercise-induced laryngeal obstruction (EILO) (previously commonly referred to as paradoxical vocal fold motion disorder, or paradoxical vocal fold motion, among other terms) are often misdiagnosed, resulting in prolonged, and at times inappropriate, clinical management. The high prevalence of misdiagnosis is largely due to a lack of universal consensus of key clinical features indicating EILO and a dearth of validated quantitative approaches to accurately detect episodic laryngeal breathing disorders (ELBD) from other pathologies. Additionally, mechanisms underlying EILO clinical presentation are poorly understood, further confounding identification and management of the condition. Therefore, the objectives of this study were twofold. The first was to identify patient-centered perception of symptoms that could distinguish adolescent athletes with EILO from athletes without the condition, at baseline (rest) and during an exercise challenge (provocation), and to quantify symptom severities for use as preliminary diagnostic benchmarks. The second objective was to investigate the merit of one commonly proposed mechanism in the EILO literature-stress reactivity (temperament)-by comparing personality traits in athletes with and without EILO.

methodsTwelve (12) athletes diagnosed with EILO and 14 healthy athletic volunteers without the condition were asked to rate the severity of their present symptoms using a 0-100 continuous visual analog scale. Participants then underwent an exercise challenge with simultaneous laryngoscopy and were asked to complete the same set of symptom severity ratings experienced during rigorous exercise. Finally, participants completed the Fear subscale on the early adolescent temperament questionnaire-revised (EATQ-R) to measure self-perceived levels of stress reactivity.

resultsThere were significant group differences for inspiratory and expiratory dyspnea with exercise (P = 0.01). Symptoms of stridor (EILO: P = .01; control: P = .001) and throat tightness (EILO: P = .01, control: P = .01) were statistically different between rest and exercise in both groups. However, no group differences were found on these two parameters (P > .05). Other symptoms from the list of previously purported symptoms indicative of ELBD (e.g. cough, dysphonia) were infrequently reported in the exercise variant. Additionally, measurements of stress reactivity on the EATQ-R Fear subscale were similar between the two athletic groups. Interestingly, EATQ-R Fear Subscale scores for both groups were significantly higher compared to typical adolescents in the U.S. population (P < .001, respectively). DISCUSSION: Results suggest dyspnea severity, particularly when experienced during an exercise-induced ELBD (EILO) episode, is the most sensitive symptom parameter to distinguish individuals with EILO from those without the condition. These findings confirm previous literature describing episodic laryngeal breathing disorders in clinical cohorts. Results also showed symptoms of throat tightness and stridor is more prevalent during exercise, compared to rest. However, the level of their severity occurred variably across both groups of athletes and may point to a less robust indication of pathology. Finally, similarities to stress reactivity between the two athletic groups imply certain temperaments historically attributed to patients with EILO may instead better reflect temperaments in competitive young athletes, in general.

conclusionStudy findings highlight the importance of using normative comparisons in the study of episodic laryngeal breathing disorders to prevent overgeneralization of characteristics to clinical cohorts. Results also speak of the clinical utility of exercise challenge to improve specificity of EILO diagnosis.