Immediate Effectiveness of Humming on the Supraglottic Compression in Subjects with Muscle Tension Dysphonia

Abstract

Aims: To verify whether humming corrects supraglottic compression in muscle tension dysphonia (MTD) patients. Methods: We enrolled 23 MTD participants (13 male, 10 female) showing supraglottic compression. Each individual was instructed to perform 3 types of phonation under transnasal laryngofiberscopy: natural phonation, humming phonation without pitch change and subsequent um-hum phonation, i.e. humming with pitch glide up as if agreeing with someone. The degree of supraglottic compression was estimated with 2 parameters. The false vocal fold and anterior-posterior indices (the FVF and AP indices) were calculated by normalizing the lateral width and AP length of the visible vocal cords at phonation normalized to the mean vocal cord length at inspiration, respectively. These indices were compared among the tasks. Results: All the MTD participants but 5 females accomplished decreases in the vocal roughness scores upon the phonatory tasks. The whole MTD group showed significant increases in the FVF and AP indices even after humming without pitch change with a dominance of the AP index. The humming-responsive MTD subgroup showed greater increases in both indices than the humming-resistant subgroup. Conclusion: These data demonstrate that humming corrects both the lateral and AP components of supraglottic compression in most MTD patients.