Effects of Thyroarytenoid Activation Induced Vibratory Asymmetry on Voice Acoustics and Perception

INTRODUCTION

Asymmetry of vocal fold (VF) vibration is common in patients with voice complaints and also observed in 10% of normophonic individuals. Although thyroarytenoid (TA) muscle activation plays a crucial role in regulating VF vibration, how TA activation asymmetry relates to voice acoustics and perception is unclear. We evaluated the relationship between TA activation asymmetry and the resulting acoustics and perception.

METHODS

An in vivo canine model of phonation was used to create symmetric and increasingly asymmetric VF vibratory conditions via graded stimulation of bilateral TA muscles. Naïve listeners (n = 89) rated the perceptual quality of 100 unique voice samples using a visual sort-and-rate task. For each phonatory condition, cepstral peak prominence (CPP), harmonic amplitude (H1-H2), and root-mean-square (RMS) energy of the voice were measured. The relationships between these metrics, vibratory asymmetry, and perceptual ratings were evaluated.

RESULTS

Increasing levels of TA asymmetry resulted in declining listener preference. Furthermore, only severely asymmetric audio samples were perceptually distinguishable from symmetric and mildly asymmetric conditions. CPP was negatively correlated with TA asymmetry: voices produced with larger degrees of asymmetry were associated with lower CPP values. Listeners preferred audio samples with higher values of CPP, high RMS energy, and lower H1-H2 (less breathy).

CONCLUSION

Listeners are sensitive to changes in voice acoustics related to vibratory asymmetry. Although increasing vibratory asymmetry is correlated with decreased perceptual ratings, mild asymmetries are perceptually tolerated. This study contributes to our understanding of voice production and quality by identifying perceptually salient and clinically meaningful asymmetry.

LEVEL OF EVIDENCE

N/A (Basic Science Study) Laryngoscope, 134:1327-1332, 2024.

Predicting Airflow from Measures Sensitive to Mid-cord Glottal Gap During the COVID-19 Pandemic

OBJECTIVES

To determine if trans-laryngeal airflow, important in assessing vocal function in paresis/paralysis and presbylarynges patients with mid-cord glottal gaps, could be predicted by other measures sensitive to mid-cord glottal gap size but with smaller risks of spreading COVID-19, and if any patient factors need consideration.

METHODS

Four populations were: unilateral vocal fold paresis/paralysis (UVFP, 148), aging and UVFP (UVFP plus aging, 22), bilateral vocal fold paresis/paralysis without airway obstruction (BVFP, 49), and presbylarynges (66). Five measures were selected from the initial clinic visit: mean airflow from repeated /pi/ syllables, longer of 2 /s/ and 2 /z/ productions, higher of 2 cepstral peak prominence smoothed for vowel /a/ (CPPSa), and Glottal Function Index (GFI). S/Z ratios were computed. Stepwise regression models used 3 measures and 5 patient factors (age, sex, etiology, diagnosis, and potentially impaired power source for voicing) to predict airflow.

RESULTS

Log-transformations were required to normalize distributions of airflow and S/Z ratio. The final model revealed age, sex, impaired power source, log-transformed S/Z ratio, and GFI predicted log-transformed airflow (R2 = .275, F[5,278] = 21.1; P < .001).

CONCLUSIONS

The amount of variance explained by the model was not high, suggesting adding other predictive variables to the model might increase the variance explained.

Incidence of Vocal Cord Paralysis in Medullary Thyroid Cancer

OBJECTIVE

Medullary thyroid cancer (MTC) is a neuroendocrine tumor that comprises 3-5% of all thyroid cancers in the United States. Vocal cord paralysis (VCP) may be due to involvement of the recurrent laryngeal nerve (RLN) preoperatively, or nerve sacrifice during surgery. The purpose of this study was to demonstrate the incidence of VCP in MTC and evaluate whether VCP has an impact on overall survival.

METHODS

This was a retrospective chart review of patients with MTC treated at Loyola University Medical Center from 2007 to 2021. Information on demographics, cancer diagnosis and treatment, laboratory data, and survival were collected.

RESULTS

A total of 79 patients were included in our study. 47 (59.5%) patients were female. The average age at the time of diagnosis was 51.3 years (SD 13.58). VCP was identified in 13 out of 79 (16.5%) patients. There were 71 patients with at least 1-year follow-up with median (Q1, Q3) years of 7.2 (3.9, 11.0). Those with VCP within 1 year had 7.2 (95% CI: 2.3, 22.7) times the risk of death compared to those without (p < 0.001).

CONCLUSION

MTC is a rare thyroid cancer, however, its incidence is on the rise. Our study suggests that the incidence of VCP in these patients appears to be higher than seen in other thyroid malignancies, and VCP is associated with a statistically significant negative impact on survival.

LEVEL OF EVIDENCE

3 Laryngoscope, 133:890-894, 2023.

Ingredients in the Visual Perception of Hypomobile Vocal Fold Motion Impairment

OBJECTIVES

The clinical determination of vocal fold (VF) hypomobility based on laryngoscopy is subjective. Previous studies point to VF motion anomaly as the most commonly reported factor in the diagnosis of hypomobility. This study tested the hypotheses that VF angular velocities and angular range of motion (ROM) differ between the two VFs in cases of unilateral VF hypomobility.

STUDY DESIGN

Retrospective.

METHODS

Semi-automated analysis of laryngoscopic videos of 18 subjects diagnosed with unilateral VF hypomobility and 13 subjects with normal VF mobility was performed to quantify/compare the VF angular velocity and ROM between the two VFs during /i/-sniff and laugh.

RESULTS

In the hypomobile VF group, 7 out of 15 (47%) videos with /i/-sniff and 5 out of 8 (63%) with laugh had a statistically significant difference in the angular velocities between the VFs in either abduction or adduction. For VF ROM, 8 out of 15 (53%) /i/-sniff videos and 4 out of 8 (50%) with laughter had a statistically significant difference between VFs. In the group without the diagnosis of VF hypomobility, 9 out of 13 subjects (69%) had no difference in VF angular velocity and ROM during either /i/-sniff or laugh.

CONCLUSIONS

Differences in VF angular velocity or ROM are measurable in a substantial subset of subjects diagnosed with unilateral VF hypomobility. Clinicians' ability to gauge VF motion goes beyond what can be extracted from frame-by-frame analysis. Other visual cues, in addition to VF angular velocity and ROM, likely contribute to the perception of unilateral VF hypomobility.

LEVEL OF EVIDENCE

3 Laryngoscope, 133:866-874, 2023.

[Polypositional transcutaneous ultrasound assessment of vocal folds mobility. Ultrasonographic sign of laryngeal dysfunction]

Fiberoptic laryngoscopy is a standard procedure for evaluation of vocal folds immobility. However, this method is invasive, requires special qualifications and technical equipment, which limits its routine use. Therefore, in daily practice, the vast majority of laryngoscopy are performed by an indirect way, the accuracy of which depends on the specialist experience and the patient compliance. On the other hand, a large number of patients require for a convenient, non-invasive and inexpensive approach to assess the vocal folds mobility. The transcutaneous laryngeal ultrasonography can be such a method. However, the disadvantage of this technique is low informative value.

OBJECTIVE

To increase the effectiveness of the diagnosis of laryngeal dysfunction using transcutaneous laryngeal ultrasonography.

MATERIAL AND METHODS

Patients underwent laryngeal ultrasonography and videolaryngoscopy before and after thyroid or parathyroid surgery. Ultrasound was performed polypositionally in the transverse and oblique planes. Functional tests with breathing and breath holding were used. Qualitative (the smile or flying bird signs, the vertical closing line of the vocal folds, synchronicity and symmetry movement of the arytenoid cartilages) and quantitative (the length contraction of the vocal cord, the rotation angle of the arytenoid cartilage) ultrasonic parameters determin the normal vocal folds mobility.

RESULTS

996 patients were included in the study. Vocal folds paresis was detected in 106 (10.6%) patients. In 72 (7.2%) cases partial impaired mobility of the vocal folds (laryngeal dyskinesia) were detected. The echographic patterns of these patients were analyzed. Qualitative ultrasound signs of laryngeal dysfunction were identified: a crooked smile or falling bird signs, a closing line deformation of the vocal folds, an arytenoid immobility. Quantitative ultrasound signs included: a decrease in the length contraction of the vocal cord and a reduction of rotation angle of the arytenoid cartilage. Unilateral laryngeal paresis was diagnosed in 101 (10.1%) patients. In unilateral disorders the rotation angle of the arytenoid on the affected side was 0-14° and the length contraction of the vocal cord was 0-1.8 mm. A crooked smile or falling bird signs, a closing line deformation of the vocal folds and immobility of the arytenoid cartilages were also determined. In 5 (0.5%) cases bilateral laryngeal paresis was revealed, in which on both sides the rotation angles of the arytenoid were 0-14°, and the length contraction of the vocal cords was 0-1.8 mm. At the same time there was no a smile or flying bird signs and a closing line of the vocal folds. Laryngeal dyskinesia was characterized by a crooked smile or falling bird signs and a closing line deformation of the vocal folds. At the same time, partial mobility of the arytenoid cartilage was noted in comparison with the contralateral side (there was a difference in the rotation angle of the arytenoid between the right and left sides of 15 ° or more degrees).

CONCLUSION

The sensitivity and specificity polypositional ultrasound of the vocal folds in women were 100% and 99.8%, in men - 85.7% and 99.2%, respectively.

Induced Paresis for Awake Laryngoscopy Procedures

This article describes an anesthetic technique that induces temporary adductor vocal fold paresis and dense sensory loss of the posterior glottis. This method allows for improved precision of treatment and patient tolerance during awake office-based laryngeal surgery.

Positive Predictive Value of Endoscopic Findings to Diagnose Vocal Fold Paresis

OBJECTIVE

Laryngoscopy corresponding with laryngeal electromyography (LEMG) is essential in diagnosing vocal fold paresis. However, baseline asymmetry or other diseases oftentimes confound the exam, making diagnosis difficult. There is currently no agreed upon endoscopic criteria proven to reliably correlate with LEMG findings. We define a set of endoscopic findings termed "paresis triad" that, when present together, reliably correlate with LEMG. The paresis triad consists of (1) hypocontraction of the weak side of the larynx with increased ventricular show, (2) hypercontraction of the intact side with bulging of the false fold covering the ventricle, and (3) tilting of the interarytenoid cleft to the weak side.

METHODS

We performed a retrospective review of patients with laryngeal asymmetry on laryngoscopy. Patients were divided into two groups: those with consistent paresis triad findings across all pitches and intensities, and those without. All patients underwent LEMG by a neurolaryngologist blinded to the laryngoscopic findings. The endoscopies were then rereviewed in a blinded manner by a second laryngologist to assess inter- and intrarater reliability for identification of the triad.

RESULTS

Twelve patients met inclusion criteria (age 50 +/-15, 7F:5M). Nine had the paresis triad. Three had an inconsistent triad. All patients with the paresis triad had LEMG findings consistent with neurologic injury on the suspected side. All patients with inconsistent triad findings had normal LEMG.

CONCLUSIONS

Our findings suggest the proposed laryngoscopic paresis triad may be useful objective criteria to diagnose paresis without the need for LEMG. Further prospective studies should examine a larger series of patients.

LEVEL OF EVIDENCE

4 Laryngoscope, 2022.

Evaluation of Laryngeal Motor Neuropathy Using Transcranial Magnetic Stimulation-Mediated Evoked Potentials

OBJECTIVES/HYPOTHESIS

Contemporary evaluation of vocal fold motion impairment largely relies on clinical laryngoscopy, with the diagnoses of vocal fold paresis (VFPa) and paralysis (VFP) being based on identification of partial and complete restriction of gross vocal fold motion, respectively. No consensus exists on the diagnostic criteria of VFPa. Laryngeal electromyography does not offer any insight into nerve conduction velocity without the adjunction of nerve conduction studies, which are impractical to perform on laryngeal nerves due to their anatomic location. The present study aims to assess the feasibility of laryngeal nerve conduction studies using transcranial magnetic stimulation (TMS)-mediated myogenic evoked potentials in the evaluation of laryngeal motor nerve function.

STUDY DESIGN

Prospective controlled cohort study.

METHODS

Enrollment of three groups of subjects defined as healthy volunteers, subjects with clinically diagnosed unilateral VFP, and subjects with clinically diagnosed unilateral VFPa of peripheral etiology. Electrodiagnostic studies consisting of bilateral stimulation of the laryngeal motor cortex, proximal cisternal, and peripheral portions of the vagus nerves were performed using figure-of-eight magnetic stimulation coils, and myogenic evoked potentials recorded from bilateral thyroarytenoid, cricothyroid, and posterior cricoarytenoid muscles using indwelling hook wire electrodes. Conduction latencies were plotted against demographic and anthropometric variables. Values obtained in healthy volunteers were used as normative references and compared to aggregated latencies of VFP and VFPa groups.

RESULTS

Enrolled subjects included 19 healthy volunteers, 5 subjects with VFP, and 4 subjects with VFPa. Normative laryngeal nerve conduction latency ranges measured in healthy subjects were comparable to prior published values, and recorded latencies increased in positive correlation with age. VFPa subjects exhibited increased latencies in affected nerve sites, while VFP subjects presented more variability in electrophysiologic manifestations, mostly dependent on their degree of compensatory reinnervation. Aberrant and synkinetic reinnervation patterns were more predominant in the VFP group than the VFPa group.

CONCLUSIONS

Laryngeal nerve conduction studies using TMS-mediated myogenic evoked potentials are safely feasible. They may serve as a useful complement to laryngeal electromyography in the evaluation of motor laryngeal neuropathy and represent a promising diagnostic modality in the evaluation of VFPa. Based on the present study's findings, the commonly accepted notion of VFPa as a manifestation of a less severe form of neuropathy than VFP may be unsubstantiated. Aging may contribute to progressive motor nerve dysfunction. Future investigations are needed to ascertain the role of nerve conduction studies in clinical laryngology practice.

LEVEL OF EVIDENCE

3 Laryngoscope, 2022.

Acute Vocal Fold Paresis and Paralysis After COVID-19 Infection: A Case Series

OBJECTIVE

Evidence demonstrates neurotropism is a common feature of coronaviruses. In our laryngology clinics we have noted an increase in cases of "idiopathic" vocal fold paralysis and paresis in patients with no history of intubation who are recovering from the novel SARS-Cov-2 coronavirus (COVID-19). This finding is concerning for a post-viral vagal neuropathy (PVVN) as a result of infection with COVID-19. Our objective is to raise the possibility that vocal fold paresis may be an additional neuropathic sequela of infection with COVID-19.

METHODS

Retrospective review of patients who tested positive for COVID-19, had no history of intubation as a result of their infection, and subsequently presented with vocal fold paresis between May 2020 and January 2021. Charts were reviewed for demographic information, confirmation of COVID-19 infection, presenting symptoms, laryngoscopy and stroboscopy exam findings, and laryngeal electromyography (LEMG) results.

RESULTS

Sixteen patients presented with new-onset dysphonia during and after recovering from a COVID-19 infection and were found to have unilateral or bilateral vocal fold paresis or paralysis. LEMG was performed in 25% of patients and confirmed the diagnosis of neuropathy in these cases.

CONCLUSIONS

We believe that COVID-19 can cause a PVVN resulting in abnormal vocal fold mobility. This diagnosis should be included in the constellation of morbidities that can result from COVID-19 as the otolaryngologist can identify this entity through careful history and examination.

Patient Self-Assessment and Acoustic Voice Analysis in Screening of Postoperative Vocal Fold Paresis and Paralysis

Background and objective:

The aim of this study was to evaluate the utility of two items in vocal fold paresis and paralysis screening after thyroid and parathyroid surgery: patient self-assessment of voice using the Voice Handicap Index and computer-based acoustic voice analysis using the Multi-Dimensional Voice Program.

Methods:

This was a prospective study of 181 patients who underwent thyroid or parathyroid surgery over a 1-year study period (2017). Preoperatively, all patients underwent laryngoscopic vocal fold inspection and acoustic voice analysis, and they completed the Voice Handicap Index questionnaire. Postoperatively, all patients underwent laryngoscopy prior to hospital discharge; 2 weeks after the surgery, they completed the Voice Handicap Index questionnaire a second time. Two weeks postoperatively, patients with vocal fold paresis or paralysis and 20 randomly selected controls without vocal fold paresis or paralysis underwent a follow-up acoustic voice analysis.

Results:

Fourteen patients had a new postoperative vocal fold paresis or paralysis. Postoperatively, the total Voice Handicap Index score was significantly higher (p = 0.040) and the change between preoperative and postoperative scores was greater (p = 0.028) in vocal fold paresis or paralysis patients. A total postoperative Voice Handicap Index score > 30 had 55% sensitivity, and 90% specificity, for vocal fold paresis or paralysis. In the postoperative Multi-Dimensional Voice Program analysis, vocal fold paresis or paralysis patients had significantly more jitter (p = 0.044). Postoperative jitter > 1.33 corresponded to 55% sensitivity, and 95% specificity, for vocal fold paresis or paralysis.

Conclusions:

In identifying postoperative vocal fold paresis or paralysis, patient self-assessment and jitter in acoustic voice analysis have high specificity but poor sensitivity. Without routine laryngoscopy, approximately half of the patients with postoperative vocal fold paresis or paralysis could be overlooked. However, if the patient has no complaints of voice disturbance 2 weeks after thyroid or parathyroid surgery, the likelihood of vocal fold paresis or paralysis is low.

Severe oropharyngeal dysphagia following COVID-19: a case report

Dysphagia may occur after a prolonged intubation due to COVID-19 but it is usually mild. Case reports on severe dysphagia following COVID-19 are infrequent. Diagnosis can be difficult because international indications recommend avoiding instrumental assessments as far as possible because of the infection risk. An early rehabilitation treatment is recommended.

Risk factors and prognosis of voice disorders after surgical treatment of thyroid and parathyroid diseases

AIM

To analyze risk factors and prognosis of voice disorders after surgical treatment of thyroid and parathyroid diseases.

MATERIAL AND METHODS

There were 1272 patients who were operated in the endocrine surgery department for the period from January 1, 2016 to April 30, 2017. We studied the incidence of VF paresis, VF paralysis, and persistent dysphonia as clinical outcomes. Potential risk factors have to be analyzed were sex and age of patients, BMI, diagnosis, surgical technique, thyroid volume, experience of the surgeon and assistant, use of intraoperative neuromonitoring, etc. RESULTS: Significant relationships of risk factors with various complications of thyroid surgery were found. In logistic regression analysis, the independent predictors of complications were the following: 1) for VF paresis - extent of surgery and thyroid volume; 2) for VF paralysis - sex, extent of surgery and thyroid volume; 3) for persistent postoperative dysphonia - age and thyroid volume.

CONCLUSION

The correlation of various risk factors with development of VF paresis, VF paralysis and persistent dysphonia were identified in patients undergoing thyroid and parathyroid surgery.

Recovery of laryngeal function after intraoperative injury to the recurrent laryngeal nerve

Loss of function in the recurrent laryngeal nerve (RLN) during thyroid/parathyroid surgery, despite a macroscopically intact nerve, is a challenge which highlights the sensitivity and complexity of laryngeal innervation. Furthermore, the uncertain prognosis stresses a lack of capability to diagnose the reason behind the impaired function. There is a great deal of literature considering risk factors, surgical technique and mechanisms outside the nerve affecting the incidence of RLN paresis during surgery. To be able to prognosticate recovery in cases of laryngeal dysfunction and voice changes after thyroid surgery, the surgeon would first need to define the presence, location, and type of laryngeal nerve injury. There is little data describing the events within the nerve and the neurobiological reasons for the impaired function related to potential recovery and prognosis. In addition, very little data has been presented in order to clarify any differences between the transient and permanent injury of the RLN. This review aims, from an anatomical and neurobiological perspective, to provide an update on the current understandings of surgically-induced injury to the laryngeal nerves.

Surgical procedures for voice restoration

Surgical procedures for voice restoration serve to improve oral communication by better vocal function. They comprise of phonomicrosurgery, with direct and indirect access to the larynx; laryngoplasty; laryngeal injections; and surgical laryngeal reinnervation. The basis for modern surgical techniques for voice disorders is the knowledge about the ultrastructure of the vocal folds and the increasing experience of surgeons in voice surgery, while facing high social and professional demands on the voice. Vocal activity limitation and participation restriction has become more important in the artistic and social areas. A number of surgical methods that have been developed worldwide for this reason, are presented in this article. Functional oriented surgery has to meet high standards. The diagnostics of vocal function has to be multi-dimensional in order to determine the indication and the appropriate surgical intervention.