Validity and reliability of grade scoring in the diagnosis of exercise-induced laryngeal obstruction.

The current gold-standard method for diagnosing exercise-induced laryngeal obstruction (EILO) is continuous laryngoscopy during exercise (CLE), with severity classified by a visual grade scoring system. We evaluated the precision of this approach, by evaluating test-retest reliability of CLE and both inter- and intra-rater variability. In this prospective case-control study, subjects completed four consecutive treadmill CLE tests under identical conditions. Laryngoscopic video recordings were anonymised and graded by three expert raters. 2 months following initial scoring, videos were re-randomised and rating repeated to assess intra-rater agreement. 20 subjects (16 cases and four controls) completed four CLE tests. The time to exhaustion increased by 30 s (95% CI 0.02-57.8, p<0.05) in the second CLE compared with the first test, but remained identical in the subsequent tests. Only one-third of subjects retained their initial diagnosis in the subsequent three tests. Inter-rater agreement on grade scores (weighted Cohen's ϰ) was 0.16-0.45, while intra-rater agreement ranged from 0.30 to 0.67. The CLE test is key in the diagnostic assessment of patients with EILO. However, the widely adopted visual grade scoring system does not appear to be a robust means for reliably classifying severity of EILO.

Larynx during exercise: the unexplored bottleneck of the airways.

Exercise-induced shortness of breath is not uncommon in otherwise healthy young people. Based on the presenting symptoms alone, it is challenging to distinguish exercise-induced asthma (EIA) from exercise-induced obstruction of central airways, sometimes leading to diagnostic errors and inadequate treatment. Central airway obstruction usually presents with exercise-induced inspiratory symptoms (EIIS) during ongoing exercise. EIIS tends to peak towards the end of an exercise session or immediately after its completion, contradicting symptoms of EIA typically peaking 3-15 min after the exercise has stopped. EIIS is usually associated with some form of laryngeal obstruction. Transnasal flexible laryngoscopy performed continuously throughout an incremental exercise test from rest to exhaustion or to intolerable symptoms is usually diagnostic, and also provides information that is important for further handling and treatment. Reflecting the complex anatomy and functional features of the larynx, exercise-induced laryngeal obstruction (EILO) appears to be a heterogeneous condition. Contradicting previous beliefs, recent literature suggests that laryngeal adduction in a majority of cases starts in supraglottic structures and that vocal cord adduction (VCD) most often occurs as a secondary phenomenon. However, EILO is poorly understood and more and better research is needed to unravel causal mechanisms. The evidence base for treatment of EILO is weak. Speech therapy, psychotherapy, biofeedback, muscle training, anticholinergic aerosols have all been applied, as has laser supraglottoplasty. Randomized controlled trials with well-defined and verifiable inclusion and success criteria are required to establish evidence-based treatment schemes.

Exercise-induced laryngeal obstruction: natural history and effect of surgical treatment.

The current follow-up study concerning the supraglottic type of exercise-induced laryngeal obstruction (EILO) was performed to reveal the natural history of supraglottic EILO and compare the symptoms, as well as the laryngeal function in conservatively versus surgically treated patients. A questionnaire-based survey was conducted 2-5 years after EILO was diagnosed by a continuous laryngoscopy exercise (CLE) test in 94 patients with a predominantly supraglottic obstruction. Seventy-one patients had been treated conservatively and 23 with laser supraglottoplasty. The questionnaire response rate was 70 and 100% in conservatively treated (CT) and surgically treated (ST) patients, respectively. A second CLE test was performed in 14 CT and 19 ST patients. A visual analogue scale on symptom severity indicated improvements in both the groups, i.e. mean values (± standard deviations) declined from 73 (20) to 53 (26) (P < 0.001) in the CT group and from 87 (26) to 25 (27) (P < 0.001) in the ST group. At follow-up, ST patients reported lower scores regarding current level of complaints, and higher ability to perform exercise, as well as to push themselves physically, all compared to CT patients (P < 0.001). CLE scores were normalized in 3 of 14 (21%) CT and 16 of 19 (84%) ST patients (Z = -3.6; P < 0.001). In conclusion, symptoms of EILO diagnosed in adolescents generally decreased during 2-5 years follow-up period but even more after the surgical treatment. Patients with supraglottic EILO may benefit from supraglottoplasty both as to laryngeal function and symptom relief.

Exercise induced dyspnea in the young. Larynx as the bottleneck of the airways.

BACKGROUND: Exercise induced asthma may symptomatically be difficult to differentiate from exercise related obstruction in the upper airways, sometimes leading to diagnostic confusion and inappropriate treatment. Larynx accounts for a significant fraction of total airway resistance, but its role as a limiting factor for airflow during exercise has been hampered by lack of diagnostic tools. We aimed to study laryngeal function in exercising humans by transnasal laryngoscopy. METHODS: Continuous video recording of the larynx was performed in parallel with continuous film recording of the upper part of the body and recording of breath sounds in subjects running to respiratory distress or exhaustion on a treadmill. RESULTS: A successful examination was obtained in 20 asymptomatic volunteers and 151 (91%) of 166 young patients with a history of inspiratory distress or stridor during exercise. At rest, six patients had abnormal laryngeal findings. During exercise, a moderate or severe adduction of laryngeal structures was observed in parallel with increasing inspiratory distress in 113 (75%) patients. In 109 of these, adduction started within supraglottic structures, followed by adduction of the vocal cords in 88. In four patients, laryngeal adduction started in the vocal cords, involving supraglottic structures secondarily in three. CONCLUSION: Larynx can safely be studied throughout a maximum intensity exercise treadmill test. A characteristic laryngeal response pattern to exercise was visualised in a large proportion of patients with suspected upper airway obstruction. Laryngoscopy during ongoing symptoms is recommended for proper assessment of these patients.

Audiovisual assessment of exercise-induced laryngeal obstruction: reliability and validity of observations.

Variable obstruction to airflow at the laryngeal level may cause respiratory distress during exercise. The Continuous Laryngoscopy Exercise (CLE)-test enables direct visualization of the larynx during ongoing exercise. The aims of this study were to establish a scoring system for laryngeal obstruction as visualized during the CLE-test as well as to assess reliability and validity of this scoring system. Continuous video recording of the larynx was performed in parallel with continuous video recording of the upper part of the body, and recording of breath sounds in 80 patients and 20 symptom-negative volunteers, running on a treadmill to respiratory maximal tolerable distress or exhaustion. Each participant scored the degree of symptoms during exercise. The scoring system contains four sub-scores, each graded from 0 to 3. Two independent laryngologists, blinded to clinical data, scored the video recordings of the larynx twice. The proportion of inter- and intra-observer agreement (equal scores) for each sub-score through these four sessions varied between 70 and 100% (weighted kappa values varied from 0.49 to 1.00 correspondingly). A positive correlation was found between CLE-test sum score and symptom score (rho = 0.75, P < 0.001). There was a significant difference in CLE-test sum score between patients (3.34 +/- 1.34) and volunteers (0.65 +/- 0.66) (P < 0.001). The single CLE-test sub-score that correlated most strongly with symptom score was glottic adduction at maximal effort (rho = 0.75, P < 0.001). The presented scoring system is reliable and valid, and we suggest that it can be used when laryngeal function during exercise is evaluated.