Voice Therapy Research Articles

How does the choice of acoustic measures influence evaluation of voice therapy treatment outcomes?

There exists a large amount of predominantly low-level evidence that behavioral voice therapy is effective but there is limited evidence that one therapy is more effective than another. Variability in voice therapy treatment outcomes research leaves clinicians with little guidance in the selection of treatment. A range of acoustic outcome measures with differing sensitivity for detecting voice change are used, statistical analyses vary and experimental design presents both pros and cons regarding applicability of outcomes to real-world clinical settings. In this presentation, a review of acoustic outcome measures, statistical methods, and research design used to evaluate treatment for two clinical cohorts—muscle tension voice disorder and gender affirming voice therapy—will be presented. Two treatments investigated across the two cohorts (Resonant Voice Therapy and Sob Voice Therapy) will be used to demonstrate how acoustic analysis has been used and how implications of results differ. Method: Comparison of data available in published literature will be presented alongside new data as yet unpublished. Acoustic measures, research design, and statistical tests used will be evaluated for sensitivity to voice change, level of evidence, and translation to clinical practice.

Objective tools in pediatric voice therapy: A path to improved outcomes

This is an invited presentation in the Special Session titled, “Voice therapy: objective measurement science and clinical efficacy.” Pediatric dysphonia (hoarseness) is a common condition with prevalence estimates ranging from 1.4% to 23.9%. Dysphonia can be detrimental to children both psychologically and academically; hence, early identification and restoration of optimal vocal health is critical. Direct visualization of vocal fold vibratory patterns is fundamental for appropriate diagnosis and treatment of vocal fold pathology. Thus, evaluation of vocal fold structure and cycle-to-cycle vibratory motion through techniques of direct visualization of the vocal fold is essential for clinical assessment and measurement of treatment outcomes. This session will discuss the most recent advances in objective voice assessment and measurement of voice therapy outcomes in children. The focus will be on discussing an innovative approach that leverages high-speed videoendoscopy and a cutting-edge custom developed laser projection system for quantitative evaluation of lesion size and comprehensive evaluation of opening and closing phase dynamics of the glottal cycle before and after voice therapy in children with vocal fold nodules.

Formant change and individual variation in male-to-female transgender speakers during voice therapy

Increased fundamental frequency (F0), resonance frequency (F2), and vowel formant frequency (F1, F2, F3) are linked to be perceived as feminine, making them desired outcomes of successful gender-affirmative voice therapy for male-to-female transwomen (MTF). However, treatment often only targets pitch, reporting F0 as an acoustic outcome measure. Vowel formants are measured less often and show inconsistent results. We retrospectively explored the effect of voice therapy on formants of Australian English /i:/. 44 MTF speakers were treated with Sob Voice Therapy using the Optimal Phonation Task, Sob Voice Quality, and Sob Variant therapy components in consecutive order. Speakers were recorded at baseline and after mastering each therapy component. F1, F2, and F3 were extracted at /i:/ target in maximally three words per component. Formant values were analyzed using linear mixed models with therapy component and therapy length as fixed effects and patient as random effect. We found no statistically significant effect of therapy component nor session on formant values at p = 0.05. Graphic inspection of the data suggests between-speaker variation, indicating that some patients may respond to treatment despite the lack of group effect. Future research may explore other acoustic outcome measures for the efficacy of gender-affirmative voice therapy.

Voice quality alteration and its potential implications for voice therapy

Modulating a speaker’s auditory feedback is a valuable technique for investigating vocal motor control. In auditory feedback alteration (AFA) experiments, participants receive real-time perturbed feedback of their voice through earphones while producing vocalizations into a microphone. Previous studies primarily focused on pitch and amplitude alterations, which typically result in compensatory vocal responses. The purpose of this study is to present a voice resynthesis system, called VQ-Synth, designed for real-time auditory feedback alteration of the speaker’s voice quality in terms of hoarseness. While an initial version of VQ-Synth was implemented using Matlab, the system has now been enhanced in a real-time framework written in ANSI-C to achieve effective voice quality resynthesis with minimal delay. Additionally, a graphical user interface (GUI) was implemented to guide participants through the experiment. This work presents the technical architecture of VQ-Synth and its intended application in AFA experiments involving both healthy and dysphonic speakers. Furthermore, we discuss the potential implications of the system in the context of auditory cognition and voice therapy. We hope that the novel capabilities of VQ-Synth open up exciting possibilities for investigating how alterations in voice quality affect vocal motor control and how this knowledge can be applied in therapeutic settings.

The effect of vocal tract semi-occlusion on the voice source and implications for voice therapy

Semi-occluded vocal tract exercises are often used in voice therapy to improve voice production. It is generally assumed that by enhancing source-filter interaction, such vocal exercises improve vocal efficiency while minimizing vocal fold collision. The goal of this computational study is to quantify such effects of source–filter interaction on the voice source. Voice simulations were performed with vocal tract constriction at various locations (false vocal folds, aryepiglottic folds, pharynx, oral cavity, and lips). The results showed that effects of vocal tract constriction on the voice source were generally small except for conditions of extreme constriction, at which constrictions at any location along the vocal tract decreased the mean and peak-to-peak amplitude of the glottal flow waveform. In general, source-filter interaction that reduced vocal fold contact pressure also decreased sound pressure level, thus making it impractical when targeting a desired output vocal intensity. While source–filter interaction is often assumed to improve vocal efficiency and economy, our results indicate that such improvements are mainly due to improvement in the filter rather than the voice source at the glottis. It is possible that speakers make additional laryngeal adjustments during vocal exercises, which may also contribute to the therapeutic benefits of such exercises.

The Estill Voice Model: A paradigm for voice training and treatment

For over 40 years, the Estill Voice Model (EVM) has defined voice quality according to movement of anatomy and physiology. EVM addresses the daunting degrees of freedom issue in voice motor control by isolating Craft of voice production from Artistry and Performance Metaphysics. The EVM proposes an integrated implicit-explicit approach for voice motor learning that flows through all training and therapy protocols. Implicit instructions include auditory-perceptual prompts (e.g., quack like a duck to produce “twang”) and explicit prompts train physiologic conditions of the vocal anatomy correlated with the voice quality (e.g., narrow your aryepiglottic sphincter to produce “twang”). Estill exercises address power, source, and filter properties of voice production, and include narrowing the aryepiglottic sphincter for “ring” in opera and belt and for increased power in hypofunctional voices, and varying vocal fold mass for register shifts and optimizing contact for hyperfunctional voices. Patients learn to feel, see, and hear the voice via multiple feedback modes including hand gestures, magnitude estimation of bodily kinesthetic effort, visual acoustic cues in real-time spectral analysis programs. This presentation will highlight objective measurement science and clinical evidence for using Estill exercises in treatment for all voices, from the novice speaker to the expert performer.

Inviting Self-Directed Learning into the College Voice Classroom

ABSTRACT This essay explores Self-Directed Learning in voice training for the performing arts. It begins with a philosophical discussion of adult learning theory, Self-Directed Learning, and the essay ends with tangible and practical steps for including Self-Directed Learning in the higher education classroom. Ultimately, the author encourages instructors to explore Self-Directed Learning teaching practices and for the field of voice studies to examine Self-Directed Learning further.

Intervention Strategies for Psychological Disorders Combined with Vocal Fold Closure Disorders: The Effects of Respiratory Transformation and Self-Vocalization Techniques

The intervention effects of psychological disorders combined with vocal fold closure disorders can be achieved through the transformation of respiratory patterns and the establishment of self-vocalization techniques. However, current research lacks sufficient consideration in sample preprocessing and integrated learning, leading to classifier misguidance, poor classification accuracy, and instability. Through the use of psychiatric scales, assessments, and diagnoses by professional physicians in psychiatric hospitals, it is frequently observed that patients with vocal fold closure disorders also exhibit tendencies or diagnoses of depression, anxiety disorders, and other mental disorders. This issue is often overlooked by voice doctors, voice trainers, and speech trainers, neglecting the coexistence of psychological disorders in individuals with vocal production disorders. Over the past six years, based on the collection and analysis of American Journal of Speech® voice biomarkers, as well as practical experience in voice training and voice rehabilitation systems, it has been discovered that the adoption of correct and effective self- vocalization techniques can effectively intervene in the psychological disorders of patients with voice production disorders. This intervention helps patients recover their psychological state related to voice production in a relatively short period of time, promotes the rehabilitation of their own psychological disorders, and maximizes the restoration of appropriate vocal fold movements. By simultaneously intervening in respiratory techniques and vocal correction for patients with psychological disorders, a synergistic effect is achieved, resulting in dual benefits from a single effort. Currently, renowned teams such as Harvard University and the University of Oxford are conducting research focusing solely on the respiratory transformation of psychological disorders, which has been published in top academic journals. Practices such as meditation and breathing exercises are also widespread in Silicon Valley, USA. However, through nearly a century of scientific research and practical application, the AJS® system has found that the intervention effects achieved through respiratory transformation, the establishment of self-vocalization techniques, and individual-specific vowel sound training exceed the impact of any psychological counseling or meditation training. Furthermore, it significantly accelerates the voice rehabilitation of patients with vocal fold closure disorders, far surpassing the effects of training solely focused on vocal correction. This research path and achievement differ from the research conducted by the Institute of Architectural Acoustics at Tsinghua University and a tertiary hospital in China, which is based on the Jindrak hypothesis proposed by Jindrak K.F. and Jindrak H. in 1988, studying the intervention of human vocalization and cranial resonance on brain nerves: "The vibration caused by vocalization can massage the brain, promote the exchange of metabolic products between brain tissue and cerebrospinal fluid, and affect arachnoid granules, accelerating the flow of cerebrospinal fluid from the subarachnoid space into the superior sagittal sinus and lateral ventricle, and then returning to the bloodstream. This accelerates the renewal of cerebrospinal fluid and enhances brain cleansing. With the rapid development and continuous evolution of artificial intelligence and big data, our team has collaborated with experts in voice feature analysis from the Massachusetts Institute of Technology and the University of Pennsylvania, as well as psychology experts from Harvard University, and jointly established a software platform based on frequency- related sound (vocal) neural conduction mechanisms, developed through integrated algorithms. Currently, we use two software programs, Apotheose®, for the collection and analysis of voice biomarkers, to assist in the voice rehabilitation and vocal correction of patients with vocal production disorders. Additionally, through software and data, we assist rehabilitation patients in establishing their own voice feature files.

Pediatric Unilateral Vocal Fold Paralysis

Purpose: The aim of this case study was to provide a review of a pediatric patient diagnosed with unilateral vocal fold paralysis. Method: The case history, voice samples, laryngeal examinations, and diagnostic probes were reviewed in a 10-year-old girl with the chief complaint of persistent dysphonia, characterized by use of both a breathy and a typical voice. Perceptual ratings were completed using both Consensus Auditory-Perceptual Evaluation of Voice and Grade, Roughness, Breathiness, Asthenia, and Strain scales. Cepstral peak prominence was determined and compared for the same file segment using both Praat and Analysis of Dysphonia in Speech and Voice analysis programs. Treatment probes during the initial preoperative visit are described. Results: The patient was able to compensate for short phonation tasks, but longer conversations were judged to have increased dysphonia and increased vocal fatigue. Because noted compensation was unable to be stabilized or sustained, both a reinnervation of the ansa cervicalis to the recurrent laryngeal nerve and voice therapy techniques were recommended as part of the multidisciplinary team plan. Conclusion: Pediatric patients with unilateral vocal fold paralysis may present with complex phonatory behaviors. This case study paired with supplemental acoustic and videostroboscopy files provides an opportunity to practice both an auditory-perceptual and acoustic assessment and to rate a laryngeal examination. Supplemental Material: https://doi.org/10.23641/asha.24163926

Complete Vocal Technique-Voice Therapy as a Novel Intervention for Rehabilitation of Laryngeal-Phonatory Dysfunction in Acquired Brain Injury Patients—An Exploratory Retrospective Study

Purpose: The purpose of this study was to explore the use of Complete Vocal Technique (CVT) voice therapy in acquired brain injury (ABI) patients Study: This study is an exploratory retrospective study. Method: Five ABI patients (two female and three male) with an average age of 20.6 years ( SD = 3.5) received CVT voice therapy from an authorized CVT teacher at a neurorehabilitation facility in conjunction with physical rehabilitation therapy and speech and language therapy. Pre- and postmeasures included Voice Handicap Index, Maximum Phonation Time, electroglottography, and acoustic measures. Results: All voice measures improved for all five patients after receiving CVT voice therapy. Voice Handicap Index scores decreased from an average of 48.4 to 22.8. Maximum Phonation Time improved while the electroglottography and acoustic data showed improved phonation stability in jitter and shimmer measures. Overall, following the intervention, patients demonstrated improved loudness range, improved range in contact quotient for different sound conditions, faster-paced speech, extended functional pitch range, and decrease in unwanted creaking and breathiness. Conclusions: The findings suggest that CVT may be used as therapy in ABI populations with promising results. Both patient self-assessment and objective voice measures demonstrate improved voice function. Given the longitudinal nature of recovery in ABI patients, more studies are needed to qualify at which stage(s) of recovery the CVT interventions are most effective and beneficial. Randomized controlled trials for specific patient populations of ABI are needed to assess the interventions' effectiveness in specific ABI diagnoses.

Bilateral Vocal Nodules Multidimensional Assessment: Pre- and Post- Speech Language Pathology Intervention

(1) Background: Vocal fold nodules are bilateral lesions that can have an important negative impact on a person’s job performance, social interaction, and quality of life. This study aims to analyze multidimensional voice evaluation outcomes in a group of patients with bilateral vocal fold nodules who underwent voice therapy. (2) Methods: A retrospective analysis was performed in 42 patients on the following voice evaluations, before and after voice therapy: visual-perceptual (video-laryngostroboscopic evaluation), auditory-perceptual voice analysis based on the GRBAS scale, and aerodynamic voice analysis. Data were collected from January 2001 to December 2019. Data analyses were performed with non-parametric tests (Wilcoxon test) using α = 0.05. (3) Results: The patient average age was 33.6.1 ± 10 years (range 19–60), and 95.2% were female. Voice therapy was delivered by an experienced speech-language pathologist once a week, with an average of 9.8 ± 3 appointments (range 8–17). Vocal fold lesions disappeared in 40.4% of the patients after voice therapy, especially in participants receiving early voice therapy (p = 0.035). When comparing pre- and post-therapy audio-perceptual results, all parameters were improved with statistical significance (p < 0.05) except for the asthenic voice scale. Aerodynamic parameters were all improved but without statistical significance (p > 0.05); (4) Conclusions: Early timing to initiate voice therapy after the onset of symptoms or diagnosis seems to be an important factor for the success of voice therapy (absence of vocal fold nodules).

Sining Kambayoka Ensemble’s Bayok: Connecting Philippines and Canada in Teaching Voice and Performance

ABSTRACT How does one mitigate the misappropriations of bayok in performance projects and voice training? Interweaving various positionalities and praxes of performance pedagogy and creation using the Meranaw bayok, this essay instigates a conversation on a decolonial and ethical appropriation of Indigenous voice style within the Philippines and Canada that seeks to connect various intercultural pedagogic and theatre praxes. By building a discourse on entwining the Philippine bayok in our theatre creation and voice training, the authors deploy a shared positionality and autoethnographic inquiry as critical approach of intersubjectivity, collaboration, and historical contextualization as interventions to misappropriation and other appropriative acts of Indigenous performance forms. In doing such, the authors enmesh three frameworks to cultivate a nascent but ongoing practice of decolonizing cultural appropriation through historical grounding, social-political contextualization, and informed collaboration. In shaping a discourse on ethical appropriation of bayok, the authors engage intercultural methods and predispositions of using bayok in teaching and performing theatrical projects while tackling certain socio-political goals like peace building, climate justice, and other global issues with self-reflexivity and collaboration.

Origins of Theatre Performance and Voice Training in Canada: Consciously Bringing Trauma-Informed Voice into View

ABSTRACT This article highlights the origins of performance training and voice pedagogy in Canada developed, in part, through the work of Michel Saint-Denis and Iris Warren. It further connects the origins of performance voice to the social sciences, highlighting the historical influences that psychodynamic therapeutic approaches have had toward informing somatic voice methodologies and pedagogy. By revisiting one thread within the historic collaboration between these fields, the article encourages actively revisiting cross-disciplinary collaborations to support knowledge-creation; which has the potential to advance both fields and encourage the development of trauma-informed, embodied frameworks to support integrated pedagogies and accessible interventions across disciplines.

Efficacy of the Grit Scale Score in Predicting Voice Therapy Adherence and Outcomes

BackgroundVoice therapy generally is considered first-line treatment for dysphonia and vocal fold paresis. It requires a commitment of time, effort and resources; currently, there is no good indicator to identify which patients are good candidates for voice therapy. The Grit scale, developed by psychologist Angela Duckworth, provides a method to quantify perseverance and commitment to long-term goals. ObjectiveWe hypothesized that the Grit scale score could correlate with patient adherence to voice therapy and outcomes, by which subjects with higher Grit scale scores demonstrate greater adherence and better outcomes. MethodsSubjects were categorized into five groups, subjects who (1) were discharged from therapy after successful completion, (2) improved to normal, near-normal, or a level of voice function with which the patients were satisfied, and then stopped attending therapy (3) attended as at least the recommended number of sessions or greater than 8 sessions with some voice improvement (4) failed to improve to a voice function level satisfactory to the patient despite attending voice therapy, (5) failed to attend voice therapy as recommended. Subjects in groups 1–4 were considered adherent to voice therapy, whereas group 5 was considered not adherent. Category 1 was considered the most favorable outcome, whereas Category 5 was considered the least favorable outcome (1 > 2 > 3 > 4 > 5). ResultsEighty-nine subjects are included in the study. The average age of subjects was 44.9 years old, and there was a nearly equal split between male and female subjects. The mean Grit score (48) of the adherent group (categories 1–4) was not significantly different from that of the non-adherent group (47, P = 0.190). Spearman's rho between Grit scale score and the categories (1 > 2 > 3 > 4 > 5) was 0.0674, P = 0.530. ConclusionNeither the analysis by groups nor the Spearman correlation across all categories supported our hypothesis that higher Grit scale scores would be associated with better adherence and outcomes. The failure of the Grit scale score to predict adherence to voice therapy and outcomes emphasizes the need for further research to find a metric that will help predict and improve patient adherence with voice therapy and voice outcomes. Further research is needed to determine why it was unable to be predictive and to confirm or refute our findings.

Auditory-Motor Function Pre- and Post-Therapy in Hyperfunctional Voice Disorders: A Case Series

Behavioral voice therapy is the most common treatment for hyperfunctional voice disorders (HVDs) but has limited long-term effectiveness since the comprehensive mechanisms underlying HVDs remain unclear. Recent work has implicated disordered sensorimotor integration during speech in some speakers with HVDs and suggests that auditory processing is a key factor to consider in HVD assessment and therapy. The purpose of this case-series study was to assess whether current voice therapy approaches for HVDs resulted in improvements to auditory-motor function. Longitudinal (pre-post) study. Pre and postvoice therapy for HVDs, 11 speakers underwent an assessment of auditory-motor function via auditory discrimination of vocal pitch, responses to unanticipated auditory perturbations, and responses to predictable auditory perturbations of vocal pitch. At the post-therapy session, 10 out of 11 participants demonstrated voice therapy success (via self-reported voice problems and/or auditory-perceptual judgements of voice by a clinician) and eight of the 11 participants demonstrated improvements in at least one measure of auditory discrimination and/or auditory-motor control. Specifically, three speakers demonstrated improvements in auditory discrimination, five speakers demonstrated improved (within typical cutoffs) responses to predictable perturbations, and two speakers demonstrated improvements in both auditory discrimination and auditory-motor measures. Together, these findings support that voice therapy in individuals with HVDs may impact auditory-motor control and highlight the potential benefit of systematically addressing auditory function in voice therapy and assessment for HVDs.

Bi-Weekly Voice Therapy Versus Weekly Voice Therapy for Muscle Tension Dysphonia

To compare the outcomes of bi-weekly voice therapy (BWVT) with weekly voice therapy on perception, acoustics, and quality of life for individuals with muscle tension dysphonia (MTD). Thirty participants with MTD were enrolled either BWVT (40min/session, two sessions per week for 4 weeks) or weekly voice therapy (40min/session, once a week for 8 weeks). Auditory perceptual ratings, acoustic parameters, and the Mandarin version of the voice-related quality of life questionnaire (MV-RQOL) scores were statistically analyzed before and after treatment. There were significant improvements in the voice qualities such as overall grade, roughness, asthenia, and strain in both groups after treatment. Acoustics analyses showed that fundamental frequency, speaking fundamental frequency, jitter, shimmer, and cepstral peak prominence significantly improved in both groups after treatment. For the MV-RQOL questionnaire scores, the result also demonstrated that both groups felt significant improvements in voice-related quality of life after treatment. However, there were no significant differences between the two groups of treatment effects. Patients with MTD can restore voice qualities and quality of life if they are able to complete a full course of voice therapy, regardless of the intensity of voice therapy. However, if they can receive the BWVT, they would be able to regain their voice faster. The results of this study can be provided as a reference for clinicians when treating patients with MTD.

The Influence of Multisensory Input On Voice Perception and Production Using Immersive Virtual Reality

The purpose was to examine the influence of auditory vs visual vs combined audiovisual input on perception and production of one's own voice, using immersive virtual reality technology. Thirty-one vocally healthy men and women were investigated under 18 sensory input conditions, using immersive virtual reality technology. Conditions included two auditory rooms with varying reverberation times, two visual rooms with varying volumes, and the combination of audiovisual conditions. All conditions were repeated with and without background noise. Speech tasks included counting, sustained vowel phonation, an all-voiced sentence from the Consensus Auditory-Perceptual Evaluation of Voice, and the first sentence from the Rainbow Passage, randomly ordered. Perception outcome measures were participants' self-reported perceptions of their vocal loudness, vocal effort, and vocal comfort in speech. Production outcome measures were sound pressure level (SPL) and spectral moments (spectral mean and standard deviation in Hz, skewness, and kurtosis). Statistical analyses used self-reported vocal effort, vocal loudness, and vocal comfort in percent (0 = "not at all," 100 = extremely), SPL in dB, and spectral moments in Hz. The reference level was a baseline audiovisual deprivation condition. Results suggested (i) increased self-perceived vocal loudness and effort, and decreased comfort, with increasing room volume, speaker-to-listener distance, audiovisual input, and background noise, and (ii) increased SPL and fluctuations in spectral moments across conditions. Not only auditory, but also visual and audiovisual input influenced voice perception and production in ways that have not been previously documented. Findings contribute to the basic science understanding the role of visual, audiovisual and auditory input in voice perception and production, and also to models of voice training and therapy. The findings also set the foundation for the use of virtual reality in voice and speech training, as a potentially power solution to the generalization problem.

Preliminary Perceptual Findings of Singing After Flow Phonation Voice Exercises for Singers in Training

Goals of voice therapy and vocal pedagogy share similar principles and therefore, therapy approaches designed to improve the disordered voice may be equally effective when used to enhance healthy voice and vice versa. The purpose of this study was to investigate the effects of flow phonation voice exercises on vocal characteristics of students in undergraduate vocal music training programs and examine their potential use in vocal pedagogy. A total of 10 cis females were recruited and were randomized into two groups: an experimental group (group 1, n=6) receiving five sessions of flow phonation intervention across 5weeks; and a control group (group 2, n=4) that did not receive any direct intervention other than vocal hygiene education. Participants provided data pertaining to auditory perception, subjective respiratory measures, voice-related quality of life, and vocal fatigue before and after 5weeks. Flow phonation exercises consisted of cup bubble blowing, gargling, and stretch and flow. Wilcoxon signed ranks test was administered to compare outcomes across time points and between groups. Data indicate statistically significant changes in auditory perception of the singing voice, and voice-related quality of life for the group that received flow phonation exercises alone. No other measures showed statistical significance. Overall, this study indicates that the use of flow phonation voice exercises has the potential to improve voice instruction within the voice studio. While our target enrollments were not met to achieve optimal statistical power, our hypotheses were at least partially supported. In particular, positive intervention-related changes were observed in self-perceived voice handicap, and auditory perception of singing which were not observed in the control group.

Long-Term Average Spectrum as an Outcome Measure of Vocal Projection After Resonant Voice Therapy in Carnatic Classical Singers

The current study evaluated the effects of resonant voice therapy (RVT) on the long-term average spectrum (LTAS) parameters of vocally healthy trained Carnatic classical singers. The objectives of the study were i) to understand the perceptual differences and ii) to understand the change in LTAS contour parameters and the alpha ratio of the sung voice samples of the trained Carnatic classical singers before and after RVT. The study used a quasi-experimental, prepost design and purposive-convenient sampling method. Nineteen vocally healthy singers (4 males and 15 females) aged 18-25 years (M=23; standard deviation [SD]=2.09) with minimum 10 years of formal Carnatic classical vocal music training volunteered to participate in the study. The audio recordings of the participants' sung aakaara (/a/ vowel singing) were obtained before and after the training. All participants were assigned to a 21-day-long RVTtraining program scheduled as 15-20 minutes sessions. The participants' pre-training and post-training singing samples were subjected to LTAS analysis. The spectral mean, SD, skewness, kurtosis, and alpha ratio were extracted from the sung samples. The mean and SD of the parameters were obtained using descriptive statistical methods. Wilcoxon signed-rank test was performed to evaluate significant differences in the obtained parameters across pre-training and post-training sung samples. Though there was an increase in perceptual vocal resonance in the post-training sung samples, the difference was observed to be statistically insignificant. The results indicated a significant difference only in the alpha ratio values, which were decreased, indicating an increase in the high-frequency energies. The descriptive statistical evaluations showed a reduction in the parameters of spectral mean, SD, skewness, and kurtosis. The observations from the current study indicated that the RVT training increased the energies of higher frequencies in the singers' voices (1-5kHz). This high-frequency energy favored improved voice projection, imparting perceptual resonanceor ringing quality of the voice.

Olfactory Rehabilitation in Total Laryngectomy Patients

Patients who undergo total laryngectomy often experience difficulties with their voice, olfaction, and taste due to the lack of airflow through nasal and oral cavities. While voice rehabilitation is more commonly performed, olfactory rehabilitation has gained importance in recent times with the use of various techniques. Previous studies have shown that incidence of hyposmia or anosmia (partial or total loss of smell) after total laryngectomy ranges from 25% to 100%. However, after olfactory rehabilitation, there has been notable improvement in olfaction, ranging from 46% to 88% of the patients. There are two main techniques for olfactory rehabilitation. The first involves creating airflow for smelling purposes by connecting the oral or nasal cavity to the tracheostoma using prosthetic laryngeal bypass devices. The second technique involves orofacial musculature training, which includes a nasal airflow-inducing maneuver known as the “polite yawning technique.” This maneuver creates negative pressure in the oropharynx, resulting in the induction of nasal airflow and potentially improving olfaction. Additionally, rehabilitation through biofeedback can facilitate airflow in the nasal cavity, further enhancing the sense of smell. In this review, we will introduce the principles, pathogenesis, and various techniques of olfactory rehabilitation, as well as summarize the outcomes of olfactory rehabilitation efforts.