Monitoring the Outcome of Phonosurgery and Vocal Exercises with Established and New Diagnostic Tools

Abstract

Instrument-assisted measuring procedures expand the options within phoniatric diagnostics by quantifying the condition of the voice. The aim of this study was to examine objective treatment-associated changes of the recently developed vocal extent measure (VEM) and the established dysphonia severity index (DSI) in relation to subjective tools, i.e., self-evaluation via voice handicap index (VHI-12) and external evaluation via auditory-perceptual assessment of hoarseness (H). The findings for H (3 raters' group assessment), VHI-12, DSI, and VEM in 152 patients of both sexes (age range 16-75 years), taken before and 3 months after phonosurgery or vocal exercises, were compared and correlated. Posttherapeutically, all of the recorded parameters improved (p < 0.001). The degree of H reduced on average by 0.5, the VHI-12 score sank by 5 points, while DSI and VEM rose by 1.5 and 19, respectively. The correlations of these changes were significant but showed gradual differences between H and VHI-12 (r = 0.3), H and DSI (r = -0.3), and H and VEM (r = -0.4). We conclude that all investigated parameters are adequate to verify therapeutic outcomes but represent different dimensions of the voice. However, changes in the degree of H as gold standard were best recognized with the new VEM.

Figure 1

List of common abbreviations in voice diagnostics.

Figure 2

Subjective vocal parameters: (a) R, (b) B, (c) H, (d) VHI-12, and (e) VHIs before treatment (light grey, left columns) and after treatment (dark grey, right columns). The abscissae show the number of patients (n), and the ordinates represent the scales of the RBH system and VHIs system (0–3) as well as the VHI-12 score.

Figure 3

Objective vocal parameters: (a) DSI and (b) VEM before and after treatment, as well as their distribution according to the degree of H. The boxplots display the median, quartiles, range of values covered by the data, and any outliers (single spots).

Figure 4

Example of phonosurgery-induced changes of laryngeal and vocal findings in a 49-year-old female dental assistant suffering from persisting dysphonia and dysodia. (a) Preoperative VLS shows a marginal edema of the right vocal fold with a glottal gap during phonation, asynchronous oscillations, and impaired mucosal wave propagation. The preoperative VRP pattern displays envelope curves for the loudest (black lines) and softest (blue lines) singing voice and for the speaking voice at different vocal intensity levels (green lines) with little dynamic and frequency ranges. The singer's formant levels (red lines) are low, characterizing the impaired concentration of acoustic energy by resonator amplification of certain frequency ranges in the vocal tract. The values of all objective voice parameters (DSI: dysphonia severity index; VEM: vocal extent measure; MPT: maximum phonation time) and subjective voice parameters (RBH: roughness, breathiness, overall grade of hoarseness; VHI-12: twelve-item voice handicap index) are reduced. (b) Three months after phonomicrosurgical removal of the edema, the treated vocal fold shows a straight margin. The glottal closure is complete, and the oscillations have normalized (mucosal wave propagation regular and symmetric). The patient reveals higher dynamic and frequency ranges of speaking and singing voice with considerably improved objective and subjective parameters.