Stroboscopic Evaluation of the Vocal Folds’ Morphometric Characteristics, between the Different Voice Categories on Professional Singers

Objective(s): The aim of this study is to explore if there is a correlation between the typical voice classification and the morphometric characteristics of the vocal folds, using video laryngeal stroboscopy, on professional singers in Greece. Methods: 70 professional singers, 50% men (35 men) and 50% women (35 women), were recruited for this study. A stroboscopic evaluation was prepared for every participant. Additionally, the voice classification and features of individuals were correlated statistically. Results: Statistically significant difference were observed between the voice categories and the size of stomatopharynx, the shape of the hard palate, the length of the vocal folds, the width and thickness of the vocal folds, as well as the tone of speech, in male singers. Statistically significant differences were also observed between the voice categories and all the variables except the shape of epiglottis, the color of speech and the shape of the vocal folds, in female singers. Conclusions: There is correlation between the morphometric characteristics of the vocal folds and the voice categories.

Image-Based Flow Prediction of Vocal Folds Using 3D Convolutional Neural Networks

In this work,a three dimensional(3D)convolutional neural network(CNN)model based on image slices of various normal and pathological vocal folds is proposed for accurate and efficient prediction of glottal flows.The 3D CNN model is composed of the feature extraction block and regression block.The feature extraction block is capable of learning low dimensional features from the high dimensional image data of the glottal shape,and the regression block is employed to flatten the output from the feature extraction block and obtain the desired glottal flow data.The input image data is the condensed set of 2D image slices captured in the axial plane of the 3D vocal folds,where these glottal shapes are synthesized based on the equations of normal vibration modes.The output flow data is the corresponding flow rate,averaged glottal pressure and nodal pressure distributions over the glottal surface.The 3D CNN model is built to establish the mapping between the input image data and output flow data.The ground-truth flow variables of each glottal shape in the training and test datasets are obtained by a high-fidelity sharp-interface immersed-boundary solver.The proposed model is trained to predict the concerned flow variables for glottal shapes in the test set.The present 3D CNN model is more efficient than traditional Computational Fluid Dynamics(CFD)models while the accuracy can still be retained,and more powerful than previous data-driven prediction models because more details of the glottal flow can be provided.The prediction performance of the trained 3D CNN model in accuracy and efficiency indicates that this model could be promising for future clinical applications.

Nonlinear oscillation of pathological vocal folds during vocalization

The extended two-mass model is adopted to analyze the nonlinear oscillation of pathological vocal folds during vocalization. Redundant tissue or area in laryngeal patients is modeled as a massless rigid connected to the upper mass of the vocal folds, and a parameter Q is introduced to represent the change of glottal configurations and tension imbalance between the left and right sides of vocal folds. Numerical simulations demonstrate that the pathological vocal-fold decreases the threshold of Q to generate nonlinear vocal oscillation, indicating the improvement of the sensitivity of vocal folds to asymmetries and enhancing the coupling between two sides. Furthermore, the pathological vocal-fold can lower the fundamental frequency and eliminate high-order harmonics, For example, the fundamental frequency decreases from 119.94 Hz to 84.95 Hz when Q=0.58 and the sub-glottal pressure 1450 Pa. However, there are no prominent effects on the amplitudes of sub-harmonic and low-order harmonics.

Paradoxical vocal fold motion masquerading as post-anesthetic respiratory distress:A case report

BACKGROUND Functional vocal cord disorders can be a differential diagnosis for postoperative upper airway obstruction requiring urgent intervention.However,this may be unfamiliar to anesthesiologists who would favor inappropriate airway intervention and increased morbidity.CASE SUMMARY A 61-year-old woman underwent cervical laminectomy,followed by laparoscopic cholecystectomy 10 mo later.Despite adequate reversal of neuromuscular blockade,the patient experienced repetitive respiratory difficulty with inspiratory stridor after extubation.After the second operation,the patient was diagnosed with paradoxical vocal fold motion(PVFM)by an otolaryngologist based on the clinical features and fiberoptic bronchoscopy results,and the patient was successfully treated.CONCLUSION PVFM should be considered a differential diagnosis if a patient presents with stridor after general anesthesia.

Adipose-derived mesenchymal stem cells accelerate nerve regeneration and functional recovery in a rat model of recurrent laryngeal nerve injury

Medialization thyroplasty or injection laryngoplasty for unilateral vocal fold paralysis cannot restore mobility of the vocal fold. Recent studies have shown that transplantation of mesenchymal stem cells is effective in the repair of nerve injuries. This study investigated wheth- er adipose-derived stem celt transplantation could repair recurrent laryngeal nerve injury. Rat models of recurrent laryngeal nerve injury were established by crushing with micro forceps. Adipose-derived mesenchymal stem cells （ADSCs; 8 ×105） or differentiated Schwann-like adipose-derived mesenchymal stem cells （dADSCs; 8×105） or extracellular matrix were injected at the site of injury. At 2, 4 and 6 weeks post-surgery, a higher density of myelinated nerve fiber, thicker myelin sheath, improved vocal fold movement, better recovery of nerve conduction capacity and reduced thyroarytenoid muscle atrophy were found in ADSCs and dADSCs groups compared with the extracellu- lar matrix group. The effects were more pronounced in the ADSCs group than in the dADSCs group. These experimental results indicated that ADSCs transplantation could be an early interventional strategy to promote regeneration after recurrent laryngeal nerve injury.

Current landscape in motoneuron regeneration and reconstruction for motor cranial nerve injuries

The intricate anatomy and physiology of cranial nerves have inspired clinicians and scientists to study their roles in the nervous system. Damage to motor cranial nerves may result from a variety of organic or iatrogenic insults and causes devastating functional impairment and disfigurement. Surgical innovations directed towards restoring function to injured motor cranial nerves and their associated organs have evolved to include nerve repair, grafting, substitution, and muscle transposition. In parallel with this progress, research on tissue-engineered constructs, development of bioelectrical interfaces, and modulation of the regenerative milieu through cellular, immunomodulatory, or neurotrophic mechanisms has proliferated to enhance the available repertoire of clinically applicable reconstructive options. Despite these advances, patients continue to suffer from functional limitations relating to inadequate cranial nerve regeneration, aberrant reinnervation, or incomplete recovery of neuromuscular function. These shortfalls have profound quality of life ramifications and provide an impetus to further elucidate mechanisms underlying cranial nerve denervation and to improve repair. In this review, we summarize the literature on reconstruction and regeneration of motor cranial nerves following various injury patterns. We focus on seven cranial nerves with predominantly efferent functions and highlight shared patterns of injuries and clinical manifestations. We also present an overview of the existing reconstructive approaches, from facial reanimation, laryngeal reinnervation, to variations of interposition nerve grafts for reconstruction. We discuss ongoing endeavors to promote nerve regeneration and to suppress aberrant reinnervation and the development of synkinesis. Insights from these studies will shed light on recent progress and new horizons in understanding the biomechanics of peripheral nerve neurobiology, with emphasis on promising strategies for optimizing neural regeneration and identifying future directions in the field of motor cranial neuron research.

Mind the gap:acute bilateral vocal cord palsy in CIDP after extending the IVIG treatment interval?

Cranial nerve involvement is rarely seen in chronic inflammatory demyelinating polyneuropathy(CIDP).We present a patient diagnosed with CIDP who was in a stable medical condition under long-term treatment with intravenous immunoglobulin(IVIG)every five weeks for more than seven years.Following a 12-day delay in the patient's regular IVIG therapy,he developed acute bilateral vocal cord palsy.The patient had to be intubated and tracheostomized because of acute respiratory distress.Weaning from mechanical ventilation was complicated due to pneumonia.After antibiotic treatment and restarting IVIG therapy vocal cord palsy rapidly improved allowing for subsequent decannulation.Although coincidence between treatment delay and symptom development does not prove definitive causality this case report may serve as a reminder how time critical IVIG therapy can be for sufficient symptom control.Moreover,it provides evidence that IVIG therapy may be effective for the treatment of cranial nerve symptoms in CIDP.

Phonosurgery:A review of current methodologies

Cold-steel has served as the gold standard modality of phonosurgery for most of its history.Surgical laser technology has revolutionized this field with its wide use of applications.Additional modalities have also been introduced such as coagulative lasers,photodynamic therapy,and cryotherapy.This review will compare the surgical modalities of cold steel,surgical lasers,phototherapy and cryotherapy.The mechanism of action,tissue effects and typical uses will be addressed for each modality.