Resonant Voice Therapy
Natalie Guel
Matthew Latta
Lauren Abowd
Isabel Trapp
Alex Mize
This paper takes a deeper look into the effects that resonant voice therapy has on professional
voice users and non-professional voice users alike.
Yiu, E. M.-L., Lo, M. C. M., & Barrett, E. A. (2016). A systematic review of resonant voice
therapy. International Journal of Speech-Language Pathology, 19(1), 17–29.
https://doi.org/10.1080/17549507.2016.1226953
This article reviews literature on resonant voice therapy and evaluates the evidence on the
effectiveness of using resonant voice therapy in treating dysphonia. The study took articles from
1974 to 2014 that were published in peer-reviewed journals that reported the effects of resonant
voice therapy and were reviewed by independent reviewers (Yiu, 20). The key words were
‘‘Humming, Resonance, Resonant Voice, Semi-occluded or closed tube phonation’’. If there
were dissertations, theses, books and non-refereed articles they were not included. The quality of
evidence was evaluated by using the Grading of Recommendations Assessment, Development
and Evaluation (GRADE) (Yiu,20).
Nine studies were selected after the search was concluded. The results found that
resonant voice therapy showed changes in perceptual voice quality and overall efficiency of
production (Yiu,28). The study did note that not all of these positive changes can be attributed to
resonant voice therapy because some of these studies did not have a control group. The study
found after its research there was “moderate” effectiveness regarding resonant voice therapy
(Yiu, 28). The study indicated that there is a need for more randomized controlled studies over
resonant voice therapy. Most of the studies found were more observational versus controlled
studies. Overall, the study found that there was moderate effectiveness from resonant voice
therapy.
Chen, S. H., Hsiao, T.-Y., Hsiao, L.-C., Chung, Y.-M., & Chiang, S.-C. (2007). Outcome of
resonant voice therapy for female teachers with voice disorders: Perceptual,
physiological, acoustic, aerodynamic, and functional measurements. Journal of Voice,
21(4), 415–425. https://doi.org/10.1016/j.jvoice.2006.02.001
This peer reviewed article discusses the outcome of resonant voice therapy for female
teachers with voice disorders. The study tests the effects of resonant voice therapy from
perceptual, physiological, acoustic, aerodynamic, and functional aspects for female teachers with
voice disorders. The study used 24 full-time female teachers in elementary, middle, and high
schools and received treatment in groups of 4, 90 minutes per session, 1 session per week for 8
weeks (Chen,416). The teachers were selected from questionnaires by speech-language
pathologists. The female teachers had to have reported at least one voice symptom and voice
symptoms frequently appear on the questionnaire. The mean age for all subjects was 37.0 years
with an age range of 26–56 years. In the initial assessment, the subjects were asked to take a
deep breath and sustain the vowel /a/ for as long as possible at a comfortable pitch and loudness
level(Chen, 417).
The outcomes were measured by auditory perceptual judgment, videostroboscopic
examination, acoustic measurements, aerodynamic measurements, and functional measurements
before and after therapy. Once therapy was completed by each subject the severity of roughness,
strain, monotone, resonance, hard attack, and glottal fry in auditory perceptual judgements, the
severity of vocal fold pathology, mucosal wave, amplitude, and vocal fold closure in
videostroboscopic examinations phonation threshold pressure, and the score of physical scale in
the Voice Handicap Index were significantly reduced (Chen, 417). In conclusion, the maximum
range of speaking Fo, speaking Fo, and maximum range of speaking intensity significantly
increased. Perturbation and breathiness measurements showed no significant changes. The study
noted that resonant voice therapy is effective for this population and is suggested for further use
with this population.
Meerschman, I., Van Lierde, K., Peeters, K., Meersman, E., Claeys, S., & D’haeseleer, E.
(2017). Short-Term Effect of Two Semi-Occluded Vocal Tract Training Programs on the
Vocal Quality of Future Occupational Voice Users: “Resonant Voice Training Using
Nasal Consonants” versus “Straw Phonation.” Journal of Speech, Language, and
Hearing Research, 60(9), 2519–2536.
The article presented is a comparison study analyzing the short-term effectiveness of two
types of vocal tract training programs: “resonant voice training” (RVT) and “straw phonation.”
The design of the study was a randomized multigroup pretest-posttest in which a control group
was present. The participants included thirty vocally healthy speech-language pathology
students, with a mean age of nineteen, who were randomly assigned to the following groups: (a.)
resonant voice training group, (b.) straw phonation group, or (c.) control group. The placements
for the thirty participants were divided evenly between the three groups (Meerschman, et al.,
2521). In each group, the participants were given their respective training for six weeks, with the
control group receiving no training. Subjective and objective assessments were administered to
each participant to evaluate their voice before the training and after. Within the subjective
assessments, participants were asked to answer a questionnaire and a self-report of their overall
vocal ability and auditory perception. In the objective assessments, the participants were given
an aerodynamic assessment, a maximum performance task, a voice range profile, a dysphonia
severity index, an acoustic voice quality index, and an acoustic analysis (Meerschman, et al.,
2521).
Resonant voice training began with the participants sustaining the phonemes /m/, /n/, and
/ŋ/. As the sessions progressed, these consonants were combined with unrounded and rounded
vowels and, subsequently, other consonants. Loudness and pitch exercises (loudness shifts, pitch
glides, melodies, etc.) were then introduced and added to each sessions’ routine. Halfway
through the duration of training, the conductors of the experiment primarily began focusing on
speech-embedded nasals and the transfer to open-mouth phonation. As this was implemented at
the word, phrase, and sentence level, resonance levels were reduced (Meerschman, et al., 2525).
Straw phonation training began by having the participants phonate the vowels /o/ and /ɔ/
through traditional drinking straws. The same pitch and loudness exercises utilized in the RVT
were implemented during the second session. During the seventh session, the conductors of the
experiment replaced the traditional drinking straws. The new straws given to the participants had
half the diameter of the first straws and provided greater resistance to the participants. Similar to
the RVT, the participants focused on the transition to open-mouth phonation halfway through the
six weeks (Meerschman, et al., 2525).
The authors found there were no correlations between the three groups in regards to
evolution over time. However, within-group results found there was significant improvement in
intensity range within the straw phonation group and substantial improvement in the dysphonia
severity range over time within the RVT group. Overall, the authors of this review found
significant improvements in both training strategies that can be beneficial to future clients
(Meerschman, et al., 2531).
Watts, C. R., Hamilton, A., Toles, L., Childs, L., & Mau, T. (2019). Intervention Outcomes of
Two Treatments for Muscle Tension Dysphonia: A Randomized Controlled Trial.
Journal of Speech, Language, and Hearing Research, 62(2), 272-282.
https://doi.org/10.1044/2018_JSLHR-S-18-0118
The purpose of this review was to compare the effectiveness of stretch-and-flow voice
therapy (SnF) and resonant voice therapy (RVT). The authors also utilized the study to test the
hypothesis that the SnF technique was noninferior to RVT (Watts, et al., 273). Each participant
within the study had muscle tension dysphonia and were randomly assigned to one of two
groups. In their groups, they received six weeks (one session per week) of their respective
therapy technique. The conductors obtained sustained vowels and connected speech samples of
each participant pre- and post-training. Throughout sessions, the participants were assessed using
the voice handicap index (VHI). Additionally, secondary measures were obtained using scales
from the Consensus Auditory-Perceptual Evaluation of Voice instrument and the acoustic voice
quality index. 21 participants completed the study and the groups consisted of 9 in the RVT
group and 12 in the SnF group (Watts, et al., 275).
The results found an overall increase in both the primary outcome (VHI) and secondary
outcomes. In regards to VHI, the participants demonstrated significant overall increase while
utilizing both treatment techniques. However, there were no statistically significant changes in
the pre-treatment and post-treatment results between the two groups. This suggests the authors’
hypothesis of SnF being noninferior to RVT is accurate and both techniques are fundamentally
capable of improving vocal hyperfunction (Watts, et al., 280).
MA, E. P.-M., CHEUNG, Y.-C., SIU, A. K.-Y., & LO, J. F.-W. (2021). The effectiveness of
vocal hygiene education with resonant voice therapy for school-aged children with vocal
nodules. Journal of Voice. https://doi.org/10.1016/j.jvoice.2021.08.015
This researchers in this study conducted a pretest/post-test control group design to
evaluate the efficacy of vocal hygiene with resonant voice therapy for school-aged children with
vocal nodules. This study was approved by a committee at the University of Hong Kong. This
study included 17 children between the following ages 6-9 years with vocal nodules. They were
recruited by the Voice Research Laboratory at the University of Hong Kong. These participants
were randomly placed in the following three groups: treatment, placebo, and a control group. All
participants in the study have all previously been diagnosed by an otolaryngologist as having
vocal nodules. All children were tested and as a result all had normal hearing and were all
Cantonese speakers. Prior to the study, none of the participants received speech or voice therapy.
Children who were a part of the treatment group received a total of six consecutive, weekly, onehour sessions of vocal hygiene with resonant voice therapy. Subjective outcome measure
included auditory-perceptual evaluation of overall dysphonia severity, the Pediatric Voice
Handicap Index (pVHI) and the children’s voice Handicap Index-10 (CVHI-10). Objective
outcome measures included acoustic analysis of fundamental frequency jitter, shimmer and
noise-to-harmonic ratio (MA,2).
Overall, the aim of the study was to evaluate the efficancy of vocal hygiene education
with resonant voice therapy for school-aged children with vocal nodules. Researchers
hypothesized that participants in the treatment group would have greater improvements than
those in the placebo group. It was found that vocal hygiene education decreased the risk of
phono-trauma through changing the way you speak and eating habits. Resonant voice therapy on
the other hand, increases out of vocal output (MA,4). Both of these approaches decrease
phonotraumatic impact stress on the vocal folds which reduces voice problems and restores the
voice. As believed, and after receiving treatment, the treatment group demonstrated
improvements in the overall quality of voice. The improvements in voice quality mirrored in
remarkable reductions in the pVHI physical scores and the total score, suggesting a better voicerelated quality of life (MA,4). This data supports the literature suggesting that vocal hygiene with
resonant voice therapy is effective in enhancing vocal quality and voice-related quality of life for
children with vocal nodules.
Saltürk, Z., Özdemir, E., Sari, H., Keten, S., Kumral, T. L., Berkiten, G., Tutar, B., & Uyar, Y.
(2019a). Assessment of resonant voice therapy in the treatment of vocal fold nodules.
Journal of Voice, 33(5). https://doi.org/10.1016/j.jvoice.2018.04.012
This study’s aim was to evaluate objective and subjective changes in the voice of adults
with vocal fold nodules who have received resonant voice therapy. This study included 26 adult
female participants with VFNs, who received RVT between January and December 2017, and 30
healthy female adults. This type of study had both a control and study group. However, the
article did not clarify how many were in each individual study groups. All patients received
treatment of vocal hygiene and voice resonant therapy. Recordings of the voice were obtained
from acoustic and aerodynamic analysis. Researchers stated that fundamental frequency,
shimmer, noise-to-harmonic reactions, and hitter were analyzed for acoustic analysis
(Saltürk,810e.3). A max phonation time was used for aerodynamic evaluation, Voice Handicap
Index 10 was completed by patients for subjective assessment. After 8 weeks of therapy, the
participants were reassessed using the above named assessments. Prior to the study, all
participants went through an entire otorhinolaryngological examination. All participants had
vocal folds assessed by use of a laryngostroboscopy. If participants have received speech therapy
and or present with any previous existing medical history such as vocal nodules or asthma, they
were excluded from the study. The adult females reported feeling symptoms between 3 months
and 1 year. Patients presented with bilateral nodules located at the junction of the anterior and
middle third of the vocal fold.
A stroboscopic analysis revealed that 14 patients had total and 9 had partial regression of
VFNs. (Saltürk,810.e2) Fundamental frequency increased in the study group and this was
statistically significant. Jitter, shimmer, and noise-to-harmonic ratio improvements were also
significant. Results indicated that the voice Handicap index score decreased and this was also
statistically significant (Saltürk,810e.1).
In conclusion, it was found that resonant voice therapy improved objective and subjective
measures of vocal function in patients with vocal fold nodules which indicates that it is an
effective treatment for VFNs.
Ouyoung, L. (Melody), Villegas, B. C., Liu, C., Talmor, G., & Sinha, U. K. (2018). Effects of
resonance voice therapy on hormone-related vocal disorders in professional singers: A
pilot study. Clinical Medicine Insights: Ear, Nose and Throat, 11, 1–7.
https://doi.org/10.1177/1179550618786934
The peer-reviewed article followed a study that was conducted to compare the vocal
effects of a control group using cervical-thoracic intervention and resonance voice therapy. The
subjects used in this study were healthy female vocalists in their postmenopausal phase and
premenstrual phase. These subjects were used to determine what intervention would permit
singers, regardless of their hormonal difference, to improve vocal performance (Ouyoung, et al.
2018).
Twenty professional singers, ten postmenopausal and ten premenstrual, from California,
were involved in the study. This was a randomized study so from the two groups the females
were split into random groups of five women. After this, the women received either resonance
voice therapy or cervical-thoracic intervention (control group). The study was conducted over a
period of one month and the subject were given fifteen-minute sessions daily (Ouyoung, et al.
2018).
Initial data for the postmenopausal subjects were collected at the first voice evaluation.
The final data for this subject group was collected at the follow-up session held one month after
the assigned voice intervention. As for the premenstrual group the initial data was collected at
days twenty-five through twenty-seven of the subject’s menstrual cycle. Then the final data was
collected the following month during the same three-day phase of the subject’s cycle. This data
was then assessed using the singer’s Voice Handicap Index (Ouyoung, et al. 2018).
The results of this study showed that resonance voice therapy decreased the Voice
Handicap Index of both the postmenopausal and premenstrual singers. The Voice Handicap
Index for the singers in both groups dropped 67% on average. As for the cervical-thoracic
intervention (control group), the Voice Handicap Index only dropped an average of 7.8%. This
result concludes that resonance voice therapy is an effective intervention for professional female
singers’ vocal changes related to hormone changes during postmenopausal and premenstrual
phases (Ouyoung, et al. 2018).
The article suggested that there be further research conducted in this area to further
support the research done in this study. This includes using a larger test group and testing nonsingers. These further studies would make the statistical analysis of this study far greater
(Ouyoung, et al. 2018).
Salvador, K., & Strohauer, K. (2010). From the voice studio to the speech clinic: perspectives on
resonance and resonant voice therapy. Journal of Singing, 67(1), 19+.
https://link.gale.com/apps/doc/A253056897/HRCA?u=txshracd2557&sid=summon&xid
=76a50967
This peer review article focused on studies that took a deeper dive into the use of
resonant voice therapy. The article said that resonant voice therapy is an intervention developed
by Katherine Verdolini for speech-language pathologists. This therapy technique includes
exercise that are already used by voice teachers. It stated that the main goal of this therapy is to
strengthen the voice to achieve a clear speaking voice with little impact on the vocal folds. This
will in turn reduce the possibility of a vocal injury and increase good vocal health (Salvador &
Strohauer, 2018).
According to this article there is a lot of evidence and research to support the use of
resonant voice therapy. The possible downsides that come with resonant voice therapy are a lack
of time, practice, and consistency in order to see benefits. One of the studies compared the use of
a microphone in the classroom and the use of resonant voice therapy. The conclusion of this
study was that they both resulted in improvement of the subjects. However, the use of the
microphone presented higher voice improvement overall. The article suggested that these results
were likely from the fact that it is easier to use a microphone than retrain the way one talks
(Salvador & Strohauer, 2018).
The article came to the conclusion that professional voice users like actors, singers, and
especially teachers are at a high chance of developing voice disorders. It also stated that there is
evidence that resonant voice therapy can be used as a treatment technique for professional voice
users. However, due to it requiring more effort and time more research will be needed. This
research should include a variety of populations, larger sample sizes, and the use of resonant
voice therapy to prevent voice disorders (Salvador & Strohauer, 2018).
Saltürk, Z., Özdemir, E., Sari, H., Keten, S., Kumral, T. L., Berkiten, G., Tutar, B., & Uyar, Y.
(2019). Assessment of Resonant Voice Therapy in the Treatment of Vocal Fold Nodules.
Journal of voice: official journal of the Voice Foundation, 33(5), 810.e1–810.e4.
The aims of this study are to measure the objective and subjective changes in voices of
adults with vocal nodules who receive resonant voice therapy (RVT). The study consisted of a
control group (30 normal females) and experimental group (26 females with unilateral vocal fold
paralysis). The test consisted of voice analysis (shimmer, jitter, etc.), aerodynamic evaluation
(maximum phonation duration), and subjective assessment (voice handicap index 10). After 8
weeks of therapy the analysis was repeated. The reanalysis of voice features showed statistical
significance in all areas. Fundamental frequency increased from 155.52+28.34 to 199.56+11.25.
Jitter, Shimmer, and noise to harmonic ratio also showed significant improvement. Voice
handicap index scores improved from 22.25+3.82 to 8.92+5.85 showing statistical significance
(Salturk, Z., 810e.4). Based on these results, the researchers found RVT improved objective and
subjective measures of adults diagnosed with vocal fold nodules.
Ma, E. P., Cheung, Y. C., Siu, A. K., & Lo, J. F. (2021). The Effectiveness of Vocal Hygiene
Education With Resonant Voice Therapy for School-Aged Children With Vocal Nodules.
Journal of voice: official journal of the Voice Foundation, S0892-1997(21)00294-0.
Advance online publication.
This study was conducted to analyze the effectiveness of vocal hygiene education for
school aged children with vocal nodules receiving resonant vocal therapy. The researchers
employed a pre/posttest control group design, consisting of 17 total participants between the age
6-9 years old that were randomly placed into three groups (Ma, 3). The groups are: control
group, treatment group, and placebo group. The children in the treatment group were the only
ones receiving therapy. Subjective and objective outcome measures included auditory-perceptual
evaluation of overall dysphonia severity, the Pediatric Voice Handicap Index (pVHI), Children's
Voice Handicap Index-10 (CVHI-10), and acoustic analysis of fundamental frequency, jitter,
shimmer and noise-to-harmonic ratio. There was statistical significance for the treatment group
in all areas except acoustic measures and CvHI-10.
References
Chen, S. H., Hsiao, T.-Y., Hsiao, L.-C., Chung, Y.-M., & Chiang, S.-C. (2007). Outcome
of resonant voice therapy for female teachers with voice disorders: Perceptual,
physiological, acoustic, aerodynamic, and functional measurements. Journal of
Voice, 21(4), 415–425. https://doi.org/10.1016/j.jvoice.2006.02.001
MA, E. P.-M., CHEUNG, Y.-C., SIU, A. K.-Y., & LO, J. F.-W. (2021). The effectiveness
of vocal hygiene education with resonant voice therapy for school-aged children
with vocal nodules. Journal of Voice. https://doi.org/10.1016/j.jvoice.2021.08.015
Meerschman, I., Van Lierde, K., Peeters, K., Meersman, E., Claeys, S., & D’haeseleer, E.
(2017). Short-Term Effect of Two Semi-Occluded Vocal Tract Training Programs
on the Vocal Quality of Future Occupational Voice Users: “Resonant Voice
Training Using Nasal Consonants” versus “Straw Phonation.” Journal of Speech,
Language, and Hearing Research, 60(9), 2519–2536.
https://doi.org/10.1044/2017_JSLHR-S-17-0017
Ouyoung, L. (Melody), Villegas, B. C., Liu, C., Talmor, G., & Sinha, U. K. (2018). Effects
of resonance voice therapy on hormone-related vocal disorders in professional
singers: A pilot study. Clinical Medicine Insights: Ear, Nose and Throat, 11, 1–7.
https://doi.org/10.1177/1179550618786934
Saltürk, Z., Özdemir, E., Sari, H., Keten, S., Kumral, T. L., Berkiten, G., Tutar, B., &
Uyar, Y. (2019a). Assessment of resonant voice therapy in the treatment of vocal
fold nodules. Journal of Voice, 33(5). https://doi.org/10.1016/j.jvoice.2018.04.012
Salvador, K., & Strohauer, K. (2010). From the voice studio to the speech clinic:
perspectives on resonance and resonant voice therapy. Journal of Singing, 67(1),
19+.
https://link.gale.com/apps/doc/A253056897/HRCA?u=txshracd2557&sid=summon
&xid=76a50967
Watts, C. R., Hamilton, A., Toles, L., Childs, L., & Mau, T. (2019). Intervention Outcomes
of Two Treatments for Muscle Tension Dysphonia: A Randomized Controlled
Trial. Journal of Speech, Language, and Hearing Research, 62(2), 272-282.
https://doi.org/10.1044/2018_JSLHR-S-18-0118
Yiu, E. M.-L., Lo, M. C. M., & Barrett, E. A. (2016). A systematic review of resonant
voice therapy. International Journal of Speech-Language Pathology, 19(1), 17–29.
https://doi.org/10.1080/17549507.2016.1226953