The breath shape controls intonation of mouse vocalizations.

Intonation in speech is the control of vocal pitch to layer expressive meaning to communication, like increasing pitch to indicate a question. Also, stereotyped patterns of pitch are used to create distinct sounds with different denotations, like in tonal languages and, perhaps, the 10 sounds in the murine lexicon. A basic tone is created by exhalation through a constricted laryngeal voice box, and it is thought that more complex utterances are produced solely by dynamic changes in laryngeal tension. But perhaps, the shifting pitch also results from altering the swiftness of exhalation. Consistent with the latter model, we describe that intonation in most vocalization types follows deviations in exhalation that appear to be generated by the re-activation of the cardinal breathing muscle for inspiration. We also show that the brainstem vocalization central pattern generator, the iRO, can create this breath pattern. Consequently, ectopic activation of the iRO not only induces phonation, but also the pitch patterns that compose most of the vocalizations in the murine lexicon. These results reveal a novel brainstem mechanism for intonation.

Biomechanics of sound production in high-pitched classical singing.

Voice production of humans and most mammals is governed by the MyoElastic-AeroDynamic (MEAD) principle, where an air stream is modulated by self-sustained vocal fold oscillation to generate audible air pressure fluctuations. An alternative mechanism is found in ultrasonic vocalizations of rodents, which are established by an aeroacoustic (AA) phenomenon without vibration of laryngeal tissue. Previously, some authors argued that high-pitched human vocalization is also produced by the AA principle. Here, we investigate the so-called "whistle register" voice production in nine professional female operatic sopranos singing a scale from C6 (≈ 1047 Hz) to G6 (≈ 1568 Hz). Super-high-speed videolaryngoscopy revealed vocal fold collision in all participants, with closed quotients from 30 to 73%. Computational modeling showed that the biomechanical requirements to produce such high-pitched voice would be an increased contraction of the cricothyroid muscle, vocal fold strain of about 50%, and high subglottal pressure. Our data suggest that high-pitched operatic soprano singing uses the MEAD mechanism. Consequently, the commonly used term "whistle register" does not reflect the physical principle of a whistle with regard to voice generation in high pitched classical singing.

Systematic Review: Singing-Based Interventions to Improve Physical Functions Related to Aging Voice in Older Adults.

PURPOSE: This systematic review aimed to evaluate the effects of singing as an intervention for aging voice. METHOD: Quantitative studies of interventions for older adults with any medical condition that involves singing as training were reviewed, measured by respiration, phonation, and posture, which are the physical functions related to the aging voice. English and Chinese studies published until April 2024 were searched using 31 electronic databases, and seven studies were included. The included articles were assessed according to the Grading of Recommendations, Assessment, Development, and Evaluations rubric. RESULTS: Seven studies were included. These studies reported outcome measures that were related to respiratory functions only. For the intervention effect, statistically significant improvements were observed in five of the included studies, among which three studies had large effect sizes. The overall level of evidence of the included studies was not high, with three studies having moderate levels and the rest having lower levels. The intervention activities included trainings other than singing. These non-singing training items may have caused co-intervention bias in the study results. CONCLUSIONS: This systematic review suggests that singing as an intervention for older adults with respiratory and cognitive problems could improve respiration and respiratory-phonatory control. However, none of the included studies covers the other two of the physical functions related to aging voice (phonatory and postural functions). The overall level of evidence of the included studies was not high either. There is a need for more research evidence in singing-based intervention specifically for patient with aging voice.

Consistency of the Signature of Phonotraumatic Vocal Hyperfunction Across Different Ambulatory Voice Measures.

PURPOSE: Although different factors and voice measures have been associated with phonotraumatic vocal hyperfunction (PVH), it is unclear what percentage of individuals with PVH exhibit such differences during their daily lives. This study used a machine learning approach to quantify the consistency with which PVH manifests according to ambulatory voice measures. Analyses included acoustic parameters of phonation as well as temporal aspects of phonation and rest, with the goal of determining optimally consistent signatures of PVH. METHOD: Ambulatory neck-surface acceleration signals were recorded over 1 week from 116 female participants diagnosed with PVH and age-, sex-, and occupation-matched vocally healthy controls. The consistency of the manifestation of PVH was defined as the percentage of participants in each group that exhibited an atypical signature based on a target voice measure. Evaluation of each machine learning model used nested 10-fold cross-validation to improve the generalizability of findings. In Experiment 1, we trained separate logistic regression models based on the distributional characteristics of 14 voice measures and durations of voicing and resting segments. In Experiments 2 and 3, features of voicing and resting duration augmented the existing distributional characteristics to examine whether more consistent signatures would result. RESULTS: Experiment 1 showed that the difference in the magnitude of the first two harmonics (H1-H2) exhibited the most consistent signature (69.4% of participants with PVH and 20.4% of controls had an atypical H1-H2 signature), followed by spectral tilt over eight harmonics (73.6% participants with PVH and 32.1% of controls had an atypical spectral tilt signature) and estimated sound pressure level (SPL; 66.9% participants with PVH and 27.6% of controls had an atypical SPL signature). Additionally, 77.6% of participants with PVH had atypical resting duration, with 68.9% exhibiting atypical voicing duration. Experiments 2 and 3 showed that augmenting the best-performing voice measures with univariate features of voicing or resting durations yielded only incremental improvement in the classifier's performance. CONCLUSIONS: Females with PVH were more likely to use more abrupt vocal fold closure (lower H1-H2), phonate louder (higher SPL), and take shorter vocal rests. They were also less likely to use higher fundamental frequency during their daily activities. The difference in the voicing duration signature between participants with PVH and controls had a large effect size, providing strong empirical evidence regarding the role of voice use in the development of PVH.

Immediate effect of inspiratory exercise with exerciser and respiratory encourager in women without vocal complaints. / Efeito imediato de exercício inspiratório com exercitador e incentivador respiratório em mulheres sem queixas vocais.

PURPOSE: To evaluate the immediate effect of the inspiratory exercise with a booster and a respiratory exerciser on the voice of women without vocal complaints. METHODS: 25 women with no vocal complaints, between 18 and 34 years old, with a score of 1 on the Vocal Disorder Screening Index (ITDV) participated. Data collection was performed before and after performing the inspiratory exercise and consisted of recording the sustained vowel /a/, connected speech and maximum phonatory times (MPT) of vowels, fricative phonemes and counting numbers. In the auditory-perceptual judgment, the Vocal Deviation Scale (VSD) was used to verify the general degree of vocal deviation. Acoustic evaluation was performed using the PRAAT software and the parameters fundamental frequency (f0), jitter, shimmer, harmonium-to-noise ratio (HNR), Cepstral Peak Prominence Smoothed (CPPS), Acoustic Voice Quality Index (AVQI) and Acoustic Breathiness Index (ABI). To measure the aerodynamic measurements, the time of each emission was extracted in the Audacity program. Data were statistically analyzed using the Statistica for Windows software and normality was tested using the Shapiro-Wilk test. To compare the results, Student's and Wilcoxon's t tests were applied, adopting a significance level of 5%. RESULTS: There were no significant differences between the results of the JPA and the acoustic measures, in the pre and post inspiratory exercise moments. As for the aerodynamic measures, it was possible to observe a significant increase in the value of the TMF /s/ (p=0.008). CONCLUSION: There was no change in vocal quality after the inspiratory exercise with stimulator and respiratory exerciser, but an increase in the MPT of the phoneme /s/ was observed after the exercise.

OBJETIVO: Avaliar o efeito imediato do exercício inspiratório com incentivador e exercitador respiratório na voz de mulheres sem queixas vocais. MÉTODO: Participaram 25 mulheres sem queixas vocais, entre 18 e 34 anos, com pontuação 1 no Índice de Triagem para Distúrbio Vocal (ITDV). A coleta de dados foi realizada nos momentos antes e após realização de exercício inspiratório e consistiu na gravação de vogal sustentada /a/, fala encadeada e tempos máximos fonatórios (TMF) de vogais, fonemas fricativos e contagem de números. No julgamento perceptivo-auditivo foi utilizada a Escala de Desvio Vocal (EDV) para verificar o grau geral do desvio vocal. Avaliação acústica foi feita no software PRAAT e foram extraídos os parâmetros frequência fundamental (f0), jitter, shimmer, proporção harmônico -ruído (HNR), Cepstral Peak Prominence Smoothed (CPPS), Acoustic Voice Quality Index (AVQI) e Acoustic Breathiness Index (ABI). Para mensuração das medidas aerodinâmicas, o tempo de emissão foi extraído no programa Audacity. Para comparar os resultados utilizou-se o teste paramétrico t de Student para amostras dependentes na análise das variáveis com distribuição normal e o teste de Wilcoxon para variáveis com distribuição não normal. RESULTADOS: Não houve diferenças entre os resultados do JPA e das medidas acústicas, nos momentos pré e pós exercício inspiratório. Quanto às medidas aerodinâmicas foi possível observar aumento significativo no valor do TMF /s/ (p=0,008). CONCLUSÃO: Não houve modificação na qualidade vocal após o exercício inspiratório com incentivador e exercitador respiratório, porém foi observado aumento do TMF do fonema /s/ após a realização do exercício.

Effects of Speech Characteristics on Electroglottographic and Instrumental Acoustic Voice Analysis Metrics in Women With Structural Dysphonia Before and After Treatment.

PURPOSE: Literature suggests a dependency of the acoustic metrics, smoothed cepstral peak prominence (CPPS) and harmonics-to-noise ratio (HNR), on human voice loudness and fundamental frequency (F0). Even though this has been explained with different oscillatory patterns of the vocal folds, so far, it has not been specifically investigated. In the present work, the influence of three elicitation levels, calibrated sound pressure level (SPL), F0 and vowel on the electroglottographic (EGG) and time-differentiated EGG (dEGG) metrics hybrid open quotient (OQ), dEGG OQ and peak dEGG, as well as on the acoustic metrics CPPS and HNR, was examined, and their suitability for voice assessment was evaluated. METHOD: In a retrospective study, 29 women with a mean age of 25 years (± 8.9, range: 18-53) diagnosed with structural vocal fold pathologies were examined before and after voice therapy or phonosurgery. Both acoustic and EGG signals were recorded simultaneously during the phonation of the sustained vowels /ɑ/, /i/, and /u/ at three elicited levels of loudness (soft/comfortable/loud) and unconstrained F0 conditions. RESULTS: A linear mixed-model analysis showed a significant effect of elicitation effort levels on peak dEGG, HNR, and CPPS (all p < .01). Calibrated SPL significantly influenced HNR and CPPS (both p < .01). Furthermore, F0 had a significant effect on peak dEGG and CPPS (p < .0001). All metrics showed significant changes with regard to vowel (all p < .05). However, the treatment had no effect on the examined metrics, regardless of the treatment type (surgery vs. voice therapy). CONCLUSIONS: The value of the investigated metrics for voice assessment purposes when sampled without sufficient control of SPL and F0 is limited, in that they are significantly influenced by the phonatory context, be it speech or elicited sustained vowels. Future studies should explore the diagnostic value of new data collation approaches such as voice mapping, which take SPL and F0 effects into account.

"Lombard Effect" and Voice Changes in Adductor Laryngeal Dystonia: A Pilot Study.

OBJECTIVES: The aim was to describe the acoustic, auditory-perceptive, and subjective voice changes under the Lombard effect (LE) in adductor laryngeal dystonia (AdLD) patients. METHODS: Subjective perception of vocal effort (OMNI Vocal Effort Scale OMNI-VES), Maximum Phonation Time (MPT), and the perceptual severity of dysphonia (GRBAS scale) were assessed in condition of stillness and under LE in 10 AdLD patients and in 10 patients with typical voice. Speakers were asked to produce the sustained vowel /a/ and to read a phonetically balanced text aloud. Using the PRAAT software, the following acoustic parameters were analyzed: Mean Pitch (Hz), Minimum and Maximum Intensity (dB), the Fraction of Locally Unvoiced Frames, the Number of Voice Breaks, the Degree of Voice Breaks (%), the Cepstral Peak Prominence-Smoothed (CPPS) (dB). RESULTS: Under LE, the AdLD group showed a decrease of both G and S parameters of GRBAS and subjective effort, mean MPT increased significantly; in the controls there were no significant changes. In both groups under LE, pitch and intensity of the sustained vowel /a/ significantly increased consistently with LE. In the AdLD group the mean gain of OMNI-VES score and the mean gain of each parameter of the speech analysis were significantly greater than the controls' ones. CONCLUSION: Auditory feedback deprivation obtained under LE improves subjective, perceptual-auditory, and acoustics parameters of AdLD patients. These findings encourage further research to provide new knowledge into the role of the auditory system in the pathogenesis of AdLD and to develop new therapeutic strategies. LEVEL OF EVIDENCE: 4 Laryngoscope, 134:3754-3760, 2024.

Immediate Ansa cervicalis-to-recurrent laryngeal nerve low-tension anastomosis: A new technique for phonation recovery and bilateral anastomoses to avoid tracheotomy.

OBJECTIVE: This case series study investigated the outcomes of an innovative approach, ansa cervicalis nerve (ACN)-to-recurrent laryngeal nerve (RLN) low-tension anastomosis. METHODS: Patients who received laryngeal nerve anastomosis between May 2015 and September 2021 at the facility were enrolled. The inclusion criteria were patients with RLN dissection and anastomosis immediately during thyroid surgery. Exclusion criteria were cases with anastomosis other than cervical loop-RLN anastomosis or pronunciation recovery time > 6 months. Patients admitted before January 2020 were assigned to group A which underwent the conventional tension-free anastomosis, and patients admitted after January 2020 were group B and underwent the innovative low-tension anastomosis (Dong's method). RESULTS: A total of 13 patients were included, 11 patients received unilateral surgery, and 2 underwent bilateral surgery. For patients who underwent unilateral anastomosis, group B had a significantly higher percentage of normal pronunciation via GRBAS scale (83.3 % vs. 0 %, p = 0.015) and voice handicap index (66.7 % vs. 0 %, p = 0.002), and shorter recovery time in pronunciation (median: 1-day vs. 4 months, p = 0.001) than those in group A after surgery. CONCLUSIONS: ACNs-to-RLN low-tension anastomosis with a laryngeal segment ≤1 cm (Dong's method) significantly improves postoperative pronunciation and recovery time. The results provide clinicians with a new strategy for ACN -to-RLN anastomosis during thyroid surgery.

Changes in and clinical utility of maximum phonation time and repetitive saliva swallowing test scores after esophagectomy.

BACKGROUND: Postoperative pneumonia in patients with esophageal cancer occurs due to swallowing dysfunction and aspiration. Recently, maximum phonation time (MPT) assessment and repetitive saliva swallowing test (RSST) have been focused on as swallowing function assessment methods that can identify patients as high risk for pneumonia. We aimed to evaluate the clinical utility of MPT assessment and RSST in patients undergoing oncological esophagectomy. METHODS: In total, 47 consecutive patients who underwent esophagectomy for esophageal cancer between August 2020 and July 2023 were eligible. The perioperative changes in MPTs and RSST scores were examined. In addition, univariate and multivariate analyses were performed to identify the predictive factors of postoperative pneumonia. RESULTS: The median MPTs before surgery and on postoperative days (PODs) 3, 6, and 10 were 18.4, 7.2, 10.6, and 12.4 s, respectively; postoperative MPTs were significantly lower than preoperative MPT. In addition, the MPT of POD 6 was significantly longer than that of POD 3 (P < 0.05). Meanwhile, there were no significant changes in perioperative RSST scores. Overall, 8 of 47 patients (17.0%) developed pneumonia postoperatively. A short MPT on POD 6 was one of the independent predictive factors for the incidence of postoperative pneumonia (odds ratio: 12.6, 95% confidence interval: 1.29-123, P = 0.03) in the multivariate analysis. CONCLUSIONS: The MPT significantly decreased after esophagectomy. However, the RSST score did not. The MPT on POD6 can be a predictor of postoperative pneumonia.

Does forced whisper have an impact on voice parameters?

OBJECTIVES: There has been the assumption that whispering may impact vocal function, leading to the widespread recommendation against its practice after phonosurgery. However, the extent to which whispering affects vocal function and vocal fold oscillation patterns remains unclear. METHODS: 10 vocally healthy subjects (5 male, 5 female) were instructed to forcefully whisper a standardized text for 10 min at a sound level of 70 dB(A), measured at a microphone distance of 30 cm to the mouth. Prior to and following the whisper loading, the dysphonia severity index was assessed. Simultaneously, recordings of high speed videolaryngoscopy (HSV), electroglottography, and audio signals during sustained phonation on the vowel /i/ (250 Hz for females and 125 Hz for males) were analyzed after segmentation of the HSV material. RESULTS: The pre-post analysis revealed only minor changes after the intervention. These changes included a rise in minimum intensity, an increase in the glottal area waveform-derived open quotient, and the glottal gap index. However, no statistically significant changes were observed in the harmonic-to-noise-ratio, the glottal- to-noise-excitation-ratio, and the electroglottographic open quotient. CONCLUSION: Overall, the study suggests that there are only small effects on vocal function in consequence of a forced whisper loading.

Effect of physical frailty on maximum phonation time in community-dwelling older individuals who visited a neurology outpatient clinic.

BACKGROUND: Maximum phonation time (MPT) is used to assess speech and other oral rehabilitation-related issues. Various factors contribute to MPT decline in older individuals. Although the impact of physical frailty on MPT has been suggested, this has not been conclusively determined. OBJECTIVE: To examine the relationship between MPT and physical frailty in community-dwelling individuals aged ≥60 years who were independently mobile. MPT-associated factors were investigated. METHODS: This cross-sectional study analysed the clinical data of 122 patients (age [interquartile range]: 80.0 [74.0-83.0] years) without dementia who visited a neurology department between 1 February 2021 and 31 January 2023. Investigated factors included age, sex, weight, height, body mass index, smoking history, grip strength, functional independence measure, vital capacity, oral diadochokinesis, MPT and the Japanese Cardiovascular Health Study score. Physical frailty was assessed based on the total score from five items (weight loss, weakness, exhaustion, slowness and low physical activity). The relationship between MPT and physical frailty was examined using Spearman's rank correlation coefficient and hierarchical multiple regression analysis. RESULTS: The MPT was negatively correlated with age (r = -0.347, p < .01) and physical frailty (r = -0.681, p < .01) and positively correlated with vital capacity (r = 0.474, p < .01) and height (r = 0.248, p < .01). The hierarchical multiple regression analysis, conducted with MPT as the dependent variable, demonstrated that physical frailty (ß = -.59, 95% confidence interval: -0.74 to 0.43, p < .001) had a strong influence on MPT. CONCLUSION: In older individuals, MPT is associated with physical frailty. When assessing MPT in clinical settings, it is advisable to perform a concurrent assessment of physical frailty.

Extrinsic Laryngeal Muscle Activity With Different Diameters and Water Depths in a Semi-Occluded Vocal Tract Exercise.

PURPOSE: Surface electromyography (sEMG) has been used to evaluate extrinsic laryngeal muscle activity during swallowing and phonation. In the current study, sEMG amplitudes were measured from the infrahyoid and suprahyoid muscles during phonation through a tube submerged in water. METHOD: The sEMG amplitude values measured from the extrinsic laryngeal muscles and the electroglottographic contact quotient (CQ) were obtained simultaneously from 62 healthy participants (31 men, 31 women) during phonation through a tube at six different depths (2, 4, 7, 10, 15, and 20 cm) while using two tubes with different diameters (1 and 0.5 cm). RESULTS: With increasing depth, the sEMG amplitude for the suprahyoid muscles increased in men and women. However, sEMG amplitudes for the infrahyoid muscles increased significantly only in men. Tube diameter had a significant effect on the suprahyoid sEMG amplitudes only for men, with higher sEMG amplitudes when phonating with a 1.0-cm tube. CQ values increased with submerged depth for both men and women. Tube diameter affected results such than CQ values were higher for men when using the wider tube and for women with the narrower tube. CONCLUSIONS: Vocal fold vibratory patterns changed with the depth of tube submersion in water for both men and women, but the patterns of muscle activation differed between the sexes. This suggests that men and women use different strategies when confronted with increased intraoral pressure during semi-occluded vocal tract exercises. In this study, sEMG provided insight into the mechanism for differences between vocally normal individuals and could help detect compensatory muscle activation during tube phonation in water for people with voice disorders.

Modification of velopharyngeal closure pressures during phonation by neuromuscular electrical stimulation in healthy individuals.

Introduction: Rhinophonia aperta may result from velopharyngeal insufficiency. Neuromuscular electrical stimulation (NMES) has been discussed in the context of muscle strengthening. The aim of this study was to evaluate in healthy subjects whether NMES can change the velopharyngeal closure pattern during phonation and increase muscle strength. Method: Eleven healthy adult volunteers (21-57 years) were included. Pressure profiles were measured by high resolution manometry (HRM): isolated sustained articulation of /a/ over 5 s (protocol 1), isolated NMES applied to soft palate above motor threshold (protocol 2) and combined articulation with NMES (protocol 3). Mean activation pressures (MeanAct), maximum pressures (Max), Area under curve (AUC) and type of velum reactions were compared. A statistical comparison of mean values of protocol 1 versus protocol 3 was carried out using the Wilcoxon signed rank test. Ordinally scaled parameters were analyzed by cross table. Results: MeanAct values measured: 17.15±20.69 mmHg (protocol 1), 34.59±25.75 mmHg (protocol 3) on average, Max: 37.86±49.17 mmHg (protocol 1), 87.24±59.53 mmHg (protocol 3) and AUC: 17.06±20.70 mmHg.s (protocol 1), 33.76±23.81 mmHg.s (protocol 3). Protocol 2 produced velum reactions on 32 occasions. These presented with MeanAct values of 13.58±12.40 mmHg, Max values of 56.14±53.14 mmHg and AUC values of 13.84±12.78 mmHg.s on average. Statistical analysis comparing protocol 1 and 3 showed more positive ranks for MeanAct, Max and AUC. This difference reached statistical significance (p=0.026) for maximum pressure values. Conclusions: NMES in combination with articulation results in a change of the velopharyngeal closure pattern with a pressure increase of around 200% in healthy individuals. This might be of therapeutic benefit for patients with velopharyngeal insufficiency.

Analyzing Vocal Fold Frequency Dynamics Using High-Speed 3D Laser Video Endoscopy.

OBJECTIVE: To examine changes in lateral and vertical vibratory motion along the anterior, middle, and posterior sections of the vocal folds, as a function of vocal frequency variations. METHODS: Absolute measurements of vocal fold surface dynamics from high-speed videoendoscopy with custom laser endoscope were made on 23 vocally healthy adults during sustained /i:/ production at 10%, 20%, and 80% of pitch range. The 3D parameters of amplitude (mm), maximum velocity opening/closing (mm/s), and mean velocity opening/closing (mm/s) were computed for the lateral and vertical vibratory motion along the anterior, middle, and posterior sections of the vocal folds. Linear mixed model analysis was conducted to evaluate the differences in (a) vocal frequency levels (high vs. normal vs. low pitch), (b) axis level (vertical vs. lateral), (c) position level (anterior vs. middle vs. posterior), and (d) gender differences (male vs. female). RESULTS: Overall, the superior surface vertical motion of the vocal fold is greater compared with the lateral motion, especially in males. Along the superior surface, the mean and maximum closing velocities are greater posteriorly for low pitch. The location (anterior, middle, and posterior) along the superior surface is relevant only for vocal fold closing rather than opening, as the dynamics are different along the various locations. CONCLUSIONS: The study highlights the significance of assessing the vertical motion of the superior surface of the vocal fold to understand the complex dynamics of voice production. LEVEL OF EVIDENCE: NA Laryngoscope, 134:3267-3276, 2024.

Zoom in: factors affecting vocal habits during online meetings, a prospective trial on 40 subjects.

PURPOSE: To identify factors that influence vocal habits during online meetings (OMs). METHODS: A prospective trial of forty participants without any known hearing or vocal cord disorders. Subjects participated in an OM divided into six randomly ordered sections, with alterations in audio/speaking equipment and language: the computer's speaker-microphone, a single earbud, two-earbuds or headphones; with/without video, native-language-speaking (Hebrew) versus second language-speaking (English). Each section included free speech, sustained phonation, and a standardized passage. Participants ranked their vocal-effort for each section. Three blinded raters independently scored the voice using the GRBAS scale, and acoustic analyses were performed. RESULTS: No significant difference in self-reported vocal effort was demonstrated between sections. Second-language speaking resulted in significantly increased intensity (p < 0.0001), frequency (p = 0.015), GRBAS (p = 0.008), and strain (p < 0.0001) scores. Using the computer's speaker/microphone resulted in significantly higher strain (p < 0.0001). Using headphones, single or two earbuds resulted in lower intensity and a lower strain score. No differences were detected between OMs with or without video. CONCLUSIONS: Using the computer's microphone/speaker or speaking in a second language during OMs, may result in vocal habits associated with vocal trauma.

Brainstem control of vocalization and its coordination with respiration.

Phonation critically depends on precise controls of laryngeal muscles in coordination with ongoing respiration. However, the neural mechanisms governing these processes remain unclear. We identified excitatory vocalization-specific laryngeal premotor neurons located in the retroambiguus nucleus (RAmVOC) in adult mice as being both necessary and sufficient for driving vocal cord closure and eliciting mouse ultrasonic vocalizations (USVs). The duration of RAmVOC activation can determine the lengths of both USV syllables and concurrent expiration periods, with the impact of RAmVOC activation depending on respiration phases. RAmVOC neurons receive inhibition from the preBötzinger complex, and inspiration needs override RAmVOC-mediated vocal cord closure. Ablating inhibitory synapses in RAmVOC neurons compromised this inspiration gating of laryngeal adduction, resulting in discoordination of vocalization with respiration. Our study reveals the circuits for vocal production and vocal-respiratory coordination.

Ansa Cervicalis External Branch Anastomosis to Restore High Tone Voice in Thyroid Surgery.

OBJECTIVES: Injury to the external branch of the superior laryngeal nerve (EBSLN) causes low-pitch voice and voice fatigue, particularly in female subjects, and available treatments are limited. Here, we assess a novel surgical procedure to restore a high-tone voice: ansa cervicalis to EBSLN anastomosis (A-E anastomosis). METHODS: Between November 2012 and April 2022, 13 patients (12 female) underwent unilateral EBSLN resection and A-E anastomosis, while 20 (16 female) underwent EBSLN resection during thyroid surgery. Patients (4494 women and 1025 men) with normal laryngoscopy scheduled for thyroid surgery served as normal controls. Phonatory function was examined using a Phonation Analyzer PA-1000 preoperatively and intermittently postoperatively. RESULTS: In patients who underwent A-E anastomosis, high-tone voice pitch decreased significantly postoperatively (673.9-471.5 Hz, p = 0.047), with restoration achieved within 5 months. The mean voice pitch in female patients who underwent A-E anastomosis, EBSLN resection, and controls were 580.4, 522.8, and 682.0 Hz, respectively, indicating a significant decrease in EBSLN resection patients than controls (p = 0.002). The (mean - 1SD) of high-tone voice pitch in female controls was 497 Hz; exceeding this may indicate recovery to a high-tone voice. Overall, 73% (8/11) of A-E anastomosis patients exceeded this value, which was marginally larger than the 43% (6/14) who underwent EBSLN resection. Data on male subjects are limited. There were no cases of adverse functional or cosmetic events. CONCLUSIONS: A-E anastomosis, a novel simple procedure, restored high-tone voice to some extent without any adverse events and thus warrants further investigation. LEVEL OF EVIDENCE: 3 Laryngoscope, 134:3868-3873, 2024.

Register transitions in an in vivo canine model as a function of intrinsic laryngeal muscle stimulation, fundamental frequency, and sound pressure level.

Phonatory instabilities and involuntary register transitions can occur during singing. However, little is known regarding the mechanisms which govern such transitions. To investigate this phenomenon, we systematically varied laryngeal muscle activation and airflow in an in vivo canine larynx model during phonation. We calculated voice range profiles showing average nerve activations for all combinations of fundamental frequency (F0) and sound pressure level (SPL). Further, we determined closed-quotient (CQ) and minimum-posterior-area (MPA) based on high-speed video recordings. While different combinations of muscle activation favored different combinations of F0 and SPL, in the investigated larynx there was a consistent region of instability at about 400 Hz which essentially precluded phonation. An explanation for this region may be a larynx specific coupling between sound source and subglottal tract or an effect based purely on larynx morphology. Register transitions crossed this region, with different combinations of cricothyroid and thyroarytenoid muscle (TA) activation stabilizing higher or lower neighboring frequencies. Observed patterns in CQ and MPA dependent on TA activation reproduced patterns found in singers in previous work. Lack of control of TA stimulation may result in phonation instabilities, and enhanced control of TA stimulation may help to avoid involuntary register transitions, especially in the singing voice.

Analysis of the relationship between emotion intensity and electrophysiology parameters during a voice examination of opera singers.

OBJECTIVES: Emotions and stress affect voice production. There are only a few reports in the literature on how changes in the autonomic nervous system affect voice production. The aim of this study was to examine emotions and measure stress reactions during a voice examination procedure, particularly changes in the muscles surrounding the larynx. MATERIAL AND METHODS: The study material included 50 healthy volunteers (26 voice workers - opera singers, 24 control subjects), all without vocal complaints. All subjects had good voice quality in a perceptual assessment. The research procedure consisted of 4 parts: an ear, nose, and throat (ENT)­phoniatric examination, surface electromyography, recording physiological indicators (heart rate and skin resistance) using a wearable wristband, and a psychological profile based on questionnaires. RESULTS: The results of the study demonstrated that there was a relationship between positive and negative emotions and stress reactions related to the voice examination procedure, as well as to the tone of the vocal tract muscles. There were significant correlations between measures describing the intensity of experienced emotions and vocal tract muscle maximum amplitude of the cricothyroid (CT) and sternocleidomastoid (SCM) muscles during phonation and non-phonation tasks. Subjects experiencing eustress (favorable stress response) had increased amplitude of submandibular and CT at rest and phonation. Subjects with high levels of negative emotions, revealed positive correlations with SCMmax during the glissando. The perception of positive and negative emotions caused different responses not only in the vocal tract but also in the vegetative system. Correlations were found between emotions and physiological parameters, most markedly in heart rate variability. A higher incidence of extreme emotions was observed in the professional group. CONCLUSIONS: The activity of the vocal tract muscles depends on the type and intensity of the emotions and stress reactions. The perception of positive and negative emotions causes different responses in the vegetative system and the vocal tract. Int J Occup Med Environ Health. 2024;37(1):84-97.

Clinical Voice Outcomes for Two Voice Rest Protocols after Phonomicrosurgery.

OBJECTIVES: Voice rest is commonly recommended for patients with benign vocal fold lesions (BVFLs) after phonomicrosurgery. The study compares the clinical voice outcomes of two protocols, 7-day complete voice rest (CVR) and 3-day CVR followed by 4-day relative voice rest (CVR + RVR), for patients with BVFLs after phonomicrosurgery. STUDY DESIGN: Prospective, randomized controlled trial. METHOD: Patients with BVFLs undergoing phonomicrosurgery were recruited prospectively and randomly assigned to either protocol. Outcomes were assessed on objective measures of acoustics (fundamental frequency, frequency range, mean intensity, cepstral peak analysis) and aerodynamics (vital capacity, airflow rate, subglottal pressure, phonation threshold pressure), as well as subjective measures, both provider-reported through the Consensus Auditory-Perceptual Evaluation of Voice (CAPE-V), and patient-reported through the Voice Handicap Index (VHI). Clinical measures were collected at three-time points: preoperatively, 1-week postoperatively (on voice rest), and 1-month postoperatively. In addition, adherence was estimated using a vocal dosimeter. RESULTS: Twenty-five patients were recruited and randomized to 7-day CVR (n = 13) and CVR + RVR regimen (n = 12). Statistically significant changes were found within both groups for subglottal pressure (p = 0.03) and VHI score (p < 0.001) comparing pre-operative baseline to 1-month postoperative follow-up. There were no statistically significant differences between the groups. Regardless of group assignment, a significant decrease in overall severity ratings for the CAPE-V was found by comparing the preoperative scores to postoperative scores at 1-week (p < 0.001) and 1-month (p < 0.001). CONCLUSION: Both groups improved their overall voice quality comparably 1 month after undergoing phonomicrosurgery as measured by objective and subjective parameters. LEVELS OF EVIDENCE: 2. Laryngoscope, 134:2812-2818, 2024.