Induced Laryngeal Obstruction (ILO) is defined by involuntary laryngeal adduction during inhalation which results in respiratory distress [1,2]. If symptoms are triggered by physical exertion, the term Exercise Induced Laryngeal Obstruction (EILO) is used [3,4]. EILO/ILO has been described using many terms including vocal cord dysfunction and paradoxical vocal fold movement [[5], [6], [7]]. Symptoms of EILO/ILO may include inhalation and/or exhalation difficulty, wheezing and/or stridor, and chest or throat tightness [2,8,9]. The resulting dyspnea often – causes panic or stress, limits physical exertion, and prevents participation in multiple activities, and thus restricts quality of life [[10], [11], [12]]. Additionally, the financial impact of EILO/ILO can be considerable as patients often see multiple providers prior to diagnosis [13]. Although the epidemiology of EILO/ILO has proved difficult to study, it is estimated that as many as 22 % of emergency department dyspnea cases result from this condition [[14], [15], [16]], with athletes being particularly susceptable [[17], [18], [19]]. EILO/ILO may affect from 4 to 8 % of the general population across the lifespan [[20], [21], [22], [23]].

Although the exact etiology of EILO/ILO is unknown, the condition is generally classified on the irritable larynx syndrome spectrum [24]. Laryngeal afferent neuroplasticity caused by irritation to laryngeal tissues may lead to neurosensory changes such as increased laryngeal sensitivity or lowered laryngeal adductor reflux activation threshold [[25], [26], [27], [28]]. Evidence also indicates a high prevalence of behavioral health conditions such as anxiety in individuals with EILO/ILO [29], however, this relationship remains unclear.

ILO triggers are varied and can be arranged into phenotypes [30]. The most common type of ILO may be induced by physical exertion (EILO) [31], explaining, in part, the high prevalence of EILO in athletes (as high as 35 %) [[32], [33], [34]]. Another common phenotype involves environmental triggers including dust, chemicals, scents, or exposure to other irritants [35,36]. Irritation from GERD or laryngopharyngeal reflux (LPR) may also contribute [37]. An additional phenotype involves any combination of exertion and environmental factors (henceforth referred to as EILO+).

The primary treatment for EILO/ILO is therapy with a speech-language pathologist (SLP) [38,39]. The effectiveness of such therapy in addressing EILO/ILO has been substantiated in the literature [12,[40], [41], [42], [43]]. Therapy has been shown to improve scores on dyspnea scales [39,44], facilitate a return to physical activity [41], and reduce reliance on asthma medications [[45], [46], [47]], Although objective measures quantifying symptoms of EILO/ILO are rare, multiple studies have documented patient-reported reductions in EILO/ILO symptoms following therapy [48]. Evidence suggests that these gains are generally retained long-term [49], thus avoiding unnecessary medical visits [50].

Although the evidence supporting EILO/ILO therapy is strong [12], the duration of this treatment has often eluded formal investigation. Clinical reports indicate that therapy often takes between 3 and 8 sessions, but these estimates have generally not been drawn from empirical data [51]. Children with EILO/ILO have been reported to require an average between 2.2 and 3.4 sessions before discharge [10,52], but it is unclear if these findings extend to adults. The lack of data examining EILO/ILO therapy duration in adults is unfortunate because it prevents patients from forming realistic expectations for how long therapy will last and the likelihood of needing to return for additional therapy following discharge. Research suggests that healthcare outcomes are ameliorated when patient expectations of treatment are clear [53], and receiving a EILO/ILO diagnosis is often a long and costly process in and of itself [13]. Although therapy duration cannot be predicted with complete accuracy, evidence-based estimations help clinicians and patients set realistic expectations for patients. This would allow patients to allocate the financial and emotional resources necessary for treatment.

The factors that influence the duration of EILO/ILO therapy remain unclear. In children, comorbid behavioral health diagnoses or a history of laryngeal surgery are associated with increased treatment duration [10]. In adults, it is possible that other factors such as voice, reflux, or allergy comorbidities may affect the number of sessions needed. It could also be that ILO phenotype impacts therapy course, as exertion or irritant induced symptoms require applying rescue techniques in different situations. Additionally, it is possible that access to healthcare could influence therapy course, as health outcomes are tied to neighborhood healthcare access [54,55]. These factors could also determine which patients return for additional sessions following initial discharge.

This study examined the duration of therapy with a SLP addressing EILO/ILO symptoms. Factors that could predict therapy duration were examined, as was the likelihood of patients returning for additional therapy sessions following initial discharge. It was hypothesized that voice or behavioral health comorbidities would lengthen the course of therapy, and that patients with EILO+ would require more sessions than those with exercise or irritant-induced symptoms alone.