Does a Systematic Vocal Exercise Program Enhance the Physiologic Range of Voice Production in Classical Singing Graduate-Level Students?

Purpose The purpose of this study was to assess the effects of vocal function exercises (VFEs) on the physiologic range of the operatic voice. The primary outcome measure was total voice range profile (VRP) area. Method Forty graduate-level opera majors were randomly assigned to experimental (training with VFE + vocal hygiene) and control (vocal hygiene only) groups. All participants underwent an acoustic voice assessment (modified VRP) pre and post 10 weeks of the assigned intervention. VRP total area was calculated and compared between and within the two groups. The total VRP area was subsequently divided into three area thirds (low, medium, and high). Results A significant improvement (increase) was observed in the VFE group for the primary outcome measure of VRP area when pre- and postvoice conditions were compared for total area, upper third, and middle third. No significant improvement was found in the vocal hygiene-only group. Conclusion Vocal training with VFEs over a 10-week period demonstrated positive effects on physiologic voice range as evidenced by an increase in the total VRP area and therefore may enhance the potential of those who already have professional voice training.

Descriptive Analysis of the Interactive Patterning of the Vocalization Subsystems in Healthy Participants: A Dynamic Systems Perspective.

Purpose Normative data for many objective voice measures are routinely used in clinical voice assessment; however, normative data reflect vocal output, but not vocalization process. The underlying physiologic processes of healthy phonation have been shown to be nonlinear and thus are likely different across individuals. Dynamic systems theory postulates that performance behaviors emerge from the nonlinear interplay of multiple physiologic components and that certain patterns are preferred and loosely governed by the interactions of physiology, task, and environment. The purpose of this study was to descriptively characterize the interactive nature of the vocalization subsystem triad in subjects with healthy voices and to determine if differing subgroups could be delineated to better understand how healthy voicing is physiologically generated. Method Respiratory kinematic, aerodynamic, and acoustic formant data were obtained from 29 individuals with healthy voices (21 female and eight male). Multivariate analyses were used to descriptively characterize the interactions among the subsystems that contributed to healthy voicing. Results Group data revealed representative measures of the 3 subsystems to be generally within the boundaries of established normative data. Despite this, 3 distinct clusters were delineated that represented 3 subgroups of individuals with differing subsystem patterning. Seven of the 9 measured variables in this study were found to be significantly different across at least 1 of the 3 subgroups indicating differing physiologic processes across individuals. Conclusion Vocal output in healthy individuals appears to be generated by distinct and preferred physiologic processes that were represented by 3 subgroups indicating that the process of vocalization is different among individuals, but not entirely idiosyncratic. Possibilities for these differences are explored using the framework of dynamic systems theory and the dynamics of emergent behaviors. A revised physiologic model of phonation that accounts for differences within and among the vocalization subsystems is described. Supplemental Material https://doi.org/10.23641/asha.7616462.

Effects of Vocal Function Exercises: A Systematic Review.

OBJECTIVES: The purpose of the present review was to systematically analyze the evidence for the effectiveness of vocal function exercises (VFEs) in improving voice production. METHODS: A systematic literature search was performed by two independent reviewers using PubMed and EBSCOHost to access relevant databases and to locate outcome studies that used VFEs as an intervention. Articles that met inclusion criteria were appraised based on the American Speech-Language and Hearing Association's levels of evidence. Effect sizes for outcomes were calculated using Hedge's g. Voice outcomes were categorized according to the five domains of voice assessment: visual perceptual analysis, acoustic analysis, aerodynamic analysis, auditory-perceptual analysis, and patient self-report measures. RESULTS: Twenty-one articles were included for the final appraisal. All studies demonstrated positive effects of VFEs as demonstrated by effect sizes across selected voice parameters. Effect sizes across parameters ranged from -0.59 to 1.55. None of the included studies reported adverse voice outcomes as a result of VFEs. CONCLUSIONS: Outcome studies demonstrate that VFEs are efficacious in enhancing vocal function in individuals with normal and disordered voices, presbylaryngeus, and professional voice users. The available research suggests moderate to strong evidence to support the use of VFEs for a variety of voice disorders.

Vocal function exercises for normal voice: With and without semi-occlusion.

PURPOSE: This study examined the effect of varying degrees of vocal tract (VT) occlusion used during Vocal Function Exercises (VFEs) on attainment of maximum phonation time (MPT) goals in normal voice. Greater VT occlusion was expected to result in increased MPT. The overarching goal was to determine whether the semi-occluded vocal tract (SOVT) posture used during VFEs could be modified while preserving efficacy. METHOD: Twenty-six females ages 18-30 participated in this pre-post longitudinal group study. Participants were randomly assigned to three experimental groups and completed a six-week VFE protocol. The first group performed exercises using the prescribed SOVT posture; the second group used the vowel /o/; group three used the vowel /a/. The primary outcome measure was MPT as performed on the exercise tasks using the assigned vocal tract posture. RESULT: MPT significantly improved in the prescribed SOVT group, but did not significantly improve in the modified /o/ and /a/ groups. CONCLUSION: The SOVT posture used during VFEs is modifiable to a small extent without significantly undermining efficacy. Changes in MPT are less robust with reduced VT occlusion. Research in a clinical population is warranted.

Vocalization Subsystem Responses to a Temporarily Induced Unilateral Vocal Fold Paralysis.

Purpose: The purpose of this study is to quantify the interactions of the 3 vocalization subsystems of respiration, phonation, and resonance before, during, and after a perturbation to the larynx (temporarily induced unilateral vocal fold paralysis) in 10 vocally healthy participants. Using dynamic systems theory as a guide, we hypothesized that data groupings would emerge revealing context-dependent patterns in the relationships of variables representing the 3 vocalization subsystems. We also hypothesized that group data would mask important individual variability important to understanding the relationships among the vocalization subsystems. Method: A perturbation paradigm was used to obtain respiratory kinematic, aerodynamic, and acoustic formant measures from 10 healthy participants (8 women, 2 men) with normal voices. Group and individual data were analyzed to provide a multilevel analysis of the data. A 3-dimensional state space model was constructed to demonstrate the interactive relationships among the 3 subsystems before, during, and after perturbation. Results: During perturbation, group data revealed that lung volume initiations and terminations were lower, with longer respiratory excursions; airflow rates increased while subglottic pressures were maintained. Acoustic formant measures indicated that the spacing between the upper formants decreased (F3-F5), whereas the spacing between F1 and F2 increased. State space modeling revealed the changing directionality and interactions among the 3 subsystems. Conclusions: Group data alone masked important variability necessary to understand the unique relationships among the 3 subsystems. Multilevel analysis permitted a richer understanding of the individual differences in phonatory regulation and permitted subgroup analysis. Dynamic systems theory may be a useful heuristic to model the interactive relationships among vocalization subsystems. Supplemental Material: https://doi.org/10.23641/asha.5913532.

Immediate Effects of the Vocal Function Exercises Semi-Occluded Mouth Posture on Glottal Airflow Parameters: A Preliminary Study.

OBJECTIVES: The study aimed to quantify immediate alterations in the airflow glottogram between the Vocal Function Exercises semi-occluded mouth posture (/ol/ with lip buzz) and the sustained vowel /o/ in individuals with normal voices, and to determine if noted changes were in agreement with established semi-occluded vocal tract aerodynamic theory. Based on semi-occluded vocal tract aerodynamic theory, we hypothesized the following immediate changes in the flow glottogram during the /ol-buzz/ condition: a greater open quotient, a greater skewing quotient, a greater maximum flow declination rate, increased average airflow, decreased peak airflow, and increased minimum airflow. METHODS: A cohort of eight men with normal voices produced the sustained vowel /o/ and the Vocal Function Exercises semi-occluded mouth posture (/ol-buzz/). Flow glottograms for both conditions were obtained from the inverse-filtered oral airflow signal via a circumferentially vented pneumotachograph mask. RESULTS: Data revealed that open quotient and minimum airflow rates increased significantly between conditions. All other measures trended in the directions predicted by aerodynamic theory, but were not statistically significant. CONCLUSIONS: The Vocal Function Exercises semi-occluded mouth posture appeared to provide an effective vocal tract semi-occlusion that immediately altered the flow glottogram in accordance with predictions made by computer-modeled aerodynamic theory.

Reliability of clinical office-based laryngeal electromyography in vocally healthy adults.

OBJECTIVE: This study aimed to conduct a 3-session reliability assessment of the laryngeal electromyography (LEMG) signal in healthy participants during intensity controlled vocalization tasks. We hypothesized that vocal intensity level and testing session would affect LEMG measures. METHODS: This prospective study used a 2-factor repeated measures design. Seven participants underwent bipolar needle LEMG of the right thyroarytenoid muscle. Data were collected over 3 testing sessions using vocalization tasks performed with visually guided intensity feedback targets (65 and 75 dB SPL). Root mean square amplitudes in microvolts were analyzed for within-session and between-session reliability. RESULTS: The main effect for intensity was found to approach significance (F = 5.71, P = .054). However, intraclass correlation coefficients (ICCs) using a 2-factor mixed random effect model indicated poor to fair signal reliability between testing sessions (ICC = 0.56 at 65 dB, 0.40 at 70 dB). Intraclass correlation coefficients for within-session data indicated excellent reliability for all testing conditions (0.84-0.98). CONCLUSION: Using a quantitative analysis protocol to inform an essentially qualitative technique, our results indicated that there was generally poor to fair reliability in the LEMG signal over testing sessions. Vocal intensity was an important variable that affected LEMG signal reliability. Standardization of LEMG protocols using vocal control parameters and quantitative analyses may help improve LEMG reliability in clinical settings.