Systematic review of the effectiveness of non-pharmacological interventions used to treat adults with inducible laryngeal obstruction

Abstract

IntroductionInducible laryngeal obstruction (ILO) describes transient laryngeal closure during respiration and can cause significant morbidity. Non-pharmacological behavioural therapy is the commonly cited treatment but efficacy is largely unknown.AimTo synthesise the current evidence base on the effectiveness of non-pharmacological interventions used to treat adults with ILO.MethodsElectronic databases (Medline/Embase/CINAHL/PsycINFO/AMED/CENTRAL) were systematically searched, informed by a population, intervention, comparison, outcome framework. Two reviewers independently screened a representative sample, with lead-author completion due to excellent inter-rater reliability. Data was extracted using a predefined piloted form. Methodological quality was appraised (blindly by two reviewers) using the Joanna Briggs Institute Critical Appraisal Tools. A narrative synthesis was performed due to heterogeneity of studies (PROSPERO registration number: CRD42020213187).ResultsInitial searching identified 3359 records. Full-text screening occurred in 92 records and 14 studies, comprising 527 participants, were deemed eligible. All studies were low-level evidence (observational by design, with four case reports), with a high risk of bias; none contained control arms for comparison. Intervention description was inconsistently and poorly described but direction of effect was positive in 76% of outcomes measured. The majority of studies showed a reduction in symptom scores and improved direct laryngeal imaging post intervention; there was an overall reduction, 59.5%, in healthcare utilisation.DiscussionThe literature is in an embryonic state and lacks robust data to truly inform on the effectiveness of non-pharmacological interventions used to treat adults with ILO. However, positive signals in the synthesis performed support non-pharmacological treatment approaches and further development is warranted.

Is trans-laryngeal ultrasound (TLUS) an accurate and acceptable tool in the assessment of inducible laryngeal obstruction? A protocol for the ILOTUS: A cross-sectional, two-stage feasibility study

“…Research indicates between 32-50% of patients with severe or difficult to control asthma may have inspiratory adduction of the vocal folds on inspiration. (Haines et al, 2022;Leong, Vertigan, et al, Fig. 2.…”

“…Speech and language therapists (SLTs) are key in the multi-disciplinary assessment and treatment for ILO (Altman et al, 2000;Christopher & Morris, 2010;Murry & Sapienza, 2010;RCSLT, 2021). SLT intervention for ILO can reduce health service utilisation and asthma medication use and includes education and instruction on targeted laryngeal control techniques (Haines et al, 2022;Murphy et al, 2021). The true efficacy of SLT treatment requires further robust and prospective study.…”

“…The true efficacy of SLT treatment requires further robust and prospective study. (Baxter et al, 2014;Haines et al, 2022;Mahoney et al, 2022;R. R. Patel et al, 2015).…”

Management of comorbidities in difficult and severe asthma

“…SLT can provide techniques for throat relaxation and cough suppression, coaching the patient to control their laryngeal response during acute attacks. Speech therapy for VCD/ILO is typically recommended, and a 2022 systematic review determined that the majority of studies demonstrated a reduction in symptoms score, although the authors noted that none contained control arms, there was an overall high risk of bias, and interpretation and intervention description was inconsistent and poorly described in most [192].…”