Comparative Analysis of Two Methods of Perceptual Voice Assessment

OBJECTIVES

The primary aim was to compare two methods for perceptual evaluation of voice - paired comparison (PC) and visual analog scale (VAS) ratings. Secondary aims were to assess the correspondence between two dimensions of voice- overall severity of voice quality and resonant voice, and to investigate the influence of rater experience on perceptual rating scores and rating confidence scores.

STUDY DESIGN

Experimental design.

METHODS

Voice samples from six children (pre and post therapy) were rated by 15 Speech-Language Pathologists specialized in voice. Raters completed four tasks corresponding to the two rating methods and voice qualities: PC-severity, PC-resonance, VAS-severity, and VAS-resonance. For PC tasks, raters chose the better of two voice samples (better voice quality or better resonance, depending on the task) and indicated the degree of confidence in each choice. Rating and confidence score were combined to produce a number on a 1-10 scale (PC-confidence adjusted). VAS ratings involved rating voices on a scale for degree of severity and resonance, respectively.

RESULTS

PC-confidence adjusted and VAS ratings were moderately correlated for overall severity and also vocal resonance. VAS ratings were normally distributed and had greater rater consistency than PC-confidence adjusted ratings. VAS scores reliably predicted binary PC choices (choice of voice sample only). Overall severity and vocal resonance were weakly correlated and rater experience was not linearly related to rating scores or confidence.

CONCLUSIONS

Results suggest that the VAS rating method holds advantages over PC, including normally distributed ratings, superior consistency of ratings, and the ability to provide more finely grained detail regarding the auditory perception of voice. Overall severity and vocal resonance were not redundant in the current data set, suggesting that resonant voice and overall severity are not isomorphic. Finally, the number of years of clinical experience was not linearly related to perceptual ratings or rating confidence.

Immediate Effects of the Semi-Occluded Ventilation Mask on Subjects Diagnosed With Functional Dysphonia and Subjects With Normal Voices

PURPOSE

The present study was designed to assess the immediate effects of the semi-occluded ventilation mask (SOVM) in subjects with functional dysphonia and subjects with normal voice.

METHODS

Sixty-four participants were included in this study (48 women and 16 men). Thirty-one of them were diagnosed with functional dysphonia and 33 with normal voice. All subjects were randomly assigned to one of two conditions: an experimental condition using the SOVM (n = 33) and a control condition with participants not using the SOVM (n = 31). Thus, within both conditions, participants could be either dysphonic or normal-voiced. This produced a total of four different groups: (1) subjects with normal voice with SOVM (n = 17), (2) subjects with normal voice without SOVM (n = 16), (3) dysphonic subjects with SOVM (n = 16), and (4) dysphonic subjects without SOVM (n = 15). All participants underwent aerodynamic, electroglottographic (EGG), and acoustic assessments, and were also asked to assess their own voice, before and after voice exercises.

RESULTS

Significant differences were found for aerodynamic, EGG, and acoustic variables when comparing SOVM conditions (dysphonic and normal) against control. Cepstral peak prominence and EGG contact quotient showed an increase among dysphonic participants with SOVM. L1-L0 showed an increase for all participants in SOVM condition (dysphonic and normal). Self-perceived resonant voice quality showed an increase for both groups in SOVM condition. Glottal airflow showed a decrease for the dysphonic participants in SOVM condition. Phonation threshold pressure and subglottic pressure showed a decrease for both groups in SOVM condition.

CONCLUSION

The present study suggests that immediate positive effect could be produced by connected speech phonatory tasks using the SOVM in both dysphonic subjects and subjects with normal voice, the change being greater among the former. SOVM seems to promote an easy voice production and a more efficient phonation.

Facial bone vibration in resonant voice production

PURPOSE

This study investigated whether resonant voice training would enhance facial bone vibration during resonant voice production.

METHODS

Twelve normal healthy participants undertook four sessions of resonant voice training, each lasted for 30 minutes. Piezoelectric accelerometer was used to measure the vibratory level on the face (nasal bridge and upper lip) and the perilaryngeal area during the production of nasal consonant /m/ and vowels /a/, /i/, and /u/ before and after the resonant voice training. The extents of vibration of these four sounds among these three sites were compared.

RESULTS

Significant increase in facial bone vibration following resonant voice training was found. The nasal bridge showed a significantly larger magnitude of increase when compared with that at the upper lip. Different sounds were also found to facilitate different magnitude of facial bone vibration. Greater magnitude of facial bone vibration was found with the phonation of /m/, /i/, and /u/ when compared with the phonation of /a/.

CONCLUSION

Resonant voice training facilitated an increase in facial bone vibration, more so at the nasal bridge area than around the upper lip. This is hypothesized to contribute to the improved resonant voice production. Sounds that involve relatively restricted oropharyngeal cavities facilitated a greater extent of facial bone vibration during resonant voice production.