The clinical features of functional dysphonia

Objective: This report aims to study the prevalence of features of laryngea l muscle tension in a population of patients with functional dysphonia (FD) and nondysphonic control subjects. Study Design: Prospective control-blind ed, cross-sectional study. Methods: We reported on a prospective control-bl inded, cross-sectional study of the prevalence of the six features describe d by Van Lawrence and the six features incorporated in the Morrison-Rammage classification A senior laryngologist and senior speech pathologist indepe ndently rated sound-free, random-sequence video laryngoscopies of 51 patien ts with FD and 52 nondysphonic control subjects. Assessments were made of t he presence or absence of the 12 laryngoscopic features of laryngeal dysfun ction, and an overall rating made of the vocal technique as "normal" or "ab normal," Results: More than 60% of the control population demonstrated 1 or more of the 12 features of hyperfunction. There was no significant differe nce in the prevalence of the six Van Lawrence features, the six Morrison-Ra mmage features, or the total number of abnormal features between patients w ith FD and control subjects. On overall assessment, both assessors noted a high prevalence (50% and 36%, respectively) of abnormal vocal technique in the control population. There was no statistical difference in the total nu mber of abnormal features observed between patients with FD and control sub jects. Positive predictive value calculations showed that the presence of a clinical feature, at best, presented a 75% chance of correctly identifying a patient with FD and, at worst, a 50% chance. Conclusion: The laryngoscop y features commonly associated with FD are frequently prevalent in the nond ysphonic population and fail to distinguish patients with FD from normal su bjects.