Muscle Tension Dysphonia: Which Laryngoscopic Features Can We Rely on for Diagnosis?

Muscle tension dysphonia (MTD) is generally diagnosed through clinical history and physical examination. Several diagnostic or classification systems exist, such as those of Van Lawrence, Morrison-Rammage, and Koufman, that delineate MTD and distinguish subtypes on the basis of laryngoscopic features. The aim of this study is to determine which of the clinical features included in these classifications are most related to the aerodynamic profile of MTD.

This is an analytic retrospective study.

This study evaluates a series of 30 consecutive patients, all over 18 years old, who attended the voice clinic consult of our department and were diagnosed with MTD. All subjects underwent fiberoptic nasal endoscopy, acoustic voice assessment, and aerodynamic voice assessment. The study only includes patients with a pathological aerodynamic profile. Presence or absence of each laryngoscopic feature in the full range of features in the Van Lawrence, Morrison-Rammage, and Koufman classification systems was evaluated independently by three experts. Cohen's kappa coefficient was calculated to indicate the degree of concordance between the experts. The chi-squared test was used to determine the degree of association between clinical features and mean value of the subglottic pressure peak (mmH₂O).

Clinical parameters that were found to have a statistically significant association (P < 0.05) with an alteration in mean subglottic pressure peak were those related to anteroposterior and lateral compression of the larynx in Van Lawrence, Morrison-Rammage, and Koufman classification systems.

While several studies have sought to clarify the laryngoscopic features of MTD, the current study is the first to evaluate these features in subjects who have been objectively diagnosed by means of aerodynamic voice assessment. The laryngoscopic features most strongly related to an aerodynamic profile of MTD were anteroposterior compression of the larynx, lateral compression of the larynx, and vestibular fold contribution to phonation.