Features of Muscle Tension Dysphonia before and after Correction of Unilateral Vocal Cord Paralysis

Abstract

We performed a retrospective, longitudinal study to compare the prevalence of hyperkinetic laryngeal features before and after successful correction in patients with unilateral vocal cord paralysis (UVCP). Eighty-six patients with UVCP who had a successful surgical correction were enrolled. Preoperative and post-operative videolaryngostroboscopy images were analyzed, and the muscle tension patterns (MTPs) were rated according to the Morrison-Rammage classification. A 4-item glottal closure index was used for each patient on study entry and for 40 normal subjects as the control group. There was no significant difference in MTP prevalence before (57%) and after (55%) surgical correction for UVCP. Although the glottal closure symptoms were tremendously improved through surgical medialization for UVCP, they persisted and were more prevalent than those in normal individuals. Persistence of MTPs after correction of UVCP may be due to intractable vocal habits or psychogenic factors.