The Characteristic Features of Muscle Tension Dysphonia before and after Surgery in Benign Lesions of the Vocal Fold

Abstract

Muscular tension dysphonia (MTD) is often concomitant in patients with underlying glottic insufficiency. It remains unclear, however, whether the characteristic features of MTD appear independently or as a consequence of dysphonia. We report here on a retrospective study of the prevalence of the four prominent characteristic features of MTD, as described by the Morrison-Rammage classification, in patients with benign lesions of the vocal fold. Two otorhinolaryngologists, independent of one another, rated the preoperative and postoperative videolaryngostroboscopic results of 260 patients to assess the presence or absence of MTD. Of the 260, 185 had vocal nodules, 49 had vocal polyp, and 26 had vocal cyst. Postoperative follow-up examinations were conducted for a period ranging from 4.5 to 35 months (mean = 18.5 months). Patient ages ranged from 18 to 76 years (mean = 47.3 years). Nearly 90% of the preoperative patients in our study cohort exhibited at least one of the MTD characteristic features. Approximately 74% of postoperative ‘asymptomatic’ patients in our study cohort exhibited at least one characteristic feature. As the characteristic features of MTD were found in both preoperative dysphonic patients and those patients who were successfully treated, MTD etiology may be causal (type I), concomitant (type IIa, IIb, III) or psychogenic (type IIa, IIb). Therefore characteristic features of MTD cannot be adequately resolved through surgery, and treatment should be supplemented by speech therapy to achieve the greatest effect in causal type I MTD.