SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: Larynx

190

Severe influenza infection represents a leading cause of global morbidity and mortality. Although influenza is primarily considered a viral infection that results in pathology limited to the respiratory system, clinical reports suggest that influenza infection is frequently associated with a number of clinical syndromes that involve organ systems outside the respiratory tract. A comprehensive Medline literature review of articles pertaining to extra-pulmonary complications of influenza infection, using organ-specific search terms, yielded 234 articles including case reports, epidemiologic investigations, and autopsy studies that were reviewed to determine the clinical involvement of other organs. The most frequently described clinical entities were viral myocarditis and viral encephalitis. Recognition of these extra-pulmonary complications is critical to determining the true burden of influenza infection and initiating organ-specific supportive care. This article is protected by copyright. All rights reserved.

Concepts: Infectious disease, Pulmonology, Respiratory system, Larynx, Upper respiratory tract, Mucus, Copyright, Respiratory tract

141

Vocal fold paralysis (BVFP) refers to neurological causes of reduced or absent movement of one or both vocal folds. Bilateral BVFP is characterized by inspiratory dyspnea due to narrowing of the airway at the glottic level with both vocal folds assuming a paramedian position. The primary objective of intervention for BVFP is to relieve patients' dyspnea. Common clinical options for management include tracheostomy, arytenoidectomy and cordotomy. Other options that have been used with varying success include reinnervation techniques and botulinum toxin (Botox) injections into the vocal fold adductors. More recently, research has focused on neuromodulation, laryngeal pacing, gene therapy, and stem cell therapy. These newer approaches have the potential advantage of avoiding damage to the voicing mechanism of the larynx with an added goal of restoring some physiologic movement of the affected vocal folds. However, clinical data are scarce for these new treatment options (i.e., reinnervation and pacing), so more investigative work is needed. These areas of research are expected to provide dramatic improvements in the treatment of BVFP.

Concepts: Stem cell, Human voice, Larynx, Phonation, Vocal folds, Phonetics, Botulinum toxin, Botulism

52

Vocal folds are used as sound sources in various species, but it is unknown how vocal fold morphologies are optimized for different acoustic objectives. Here we identify two main variables affecting range of vocal fold vibration frequency, namely vocal fold elongation and tissue fiber stress. A simple vibrating string model is used to predict fundamental frequency ranges across species of different vocal fold sizes. While average fundamental frequency is predominantly determined by vocal fold length (larynx size), range of fundamental frequency is facilitated by (1) laryngeal muscles that control elongation and by (2) nonlinearity in tissue fiber tension. One adaptation that would increase fundamental frequency range is greater freedom in joint rotation or gliding of two cartilages (thyroid and cricoid), so that vocal fold length change is maximized. Alternatively, tissue layers can develop to bear a disproportionate fiber tension (i.e., a ligament with high density collagen fibers), increasing the fundamental frequency range and thereby vocal versatility. The range of fundamental frequency across species is thus not simply one-dimensional, but can be conceptualized as the dependent variable in a multi-dimensional morphospace. In humans, this could allow for variations that could be clinically important for voice therapy and vocal fold repair. Alternative solutions could also have importance in vocal training for singing and other highly-skilled vocalizations.

Concepts: Acoustics, Human voice, Larynx, Phonation, Vocal folds, Phonetics, Fundamental frequency, Histology of the Vocal Folds

42

Dynamic MRI analysis of phonation has gathered interest in voice and speech physiology. However, there are limited data addressing the extent to which articulation is dependent on loudness.

Concepts: Human voice, Larynx, Phonation, Singing, Vocal range, Head voice, Chest voice, Whistle register

38

From complex songs to simple honks, birds produce sounds using a unique vocal organ called the syrinx. Located close to the heart at the tracheobronchial junction, vocal folds or membranes attached to modified mineralized rings vibrate to produce sound. Syringeal components were not thought to commonly enter the fossil record, and the few reported fossilized parts of the syrinx are geologically young (from the Pleistocene and Holocene (approximately 2.5 million years ago to the present)). The only known older syrinx is an Eocene specimen that was not described or illustrated. Data on the relationship between soft tissue structures and syringeal three-dimensional geometry are also exceptionally limited. Here we describe the first remains, to our knowledge, of a fossil syrinx from the Mesozoic Era, which are preserved in three dimensions in a specimen from the Late Cretaceous (approximately 66 to 69 million years ago) of Antarctica. With both cranial and postcranial remains, the new Vegavis iaai specimen is the most complete to be recovered from a part of the radiation of living birds (Aves). Enhanced-contrast X-ray computed tomography (CT) of syrinx structure in twelve extant non-passerine birds, as well as CT imaging of the Vegavis and Eocene syrinxes, informs both the reconstruction of ancestral states in birds and properties of the vocal organ in the extinct species. Fused rings in Vegavis form a well-mineralized pessulus, a derived neognath bird feature, proposed to anchor enlarged vocal folds or labia. Left-right bronchial asymmetry, as seen in Vegavis, is only known in extant birds with two sets of vocal fold sound sources. The new data show the fossilization potential of the avian vocal organ and beg the question why these remains have not been found in other dinosaurs. The lack of other Mesozoic tracheobronchial remains, and the poorly mineralized condition in archosaurian taxa without a syrinx, may indicate that a complex syrinx was a late arising feature in the evolution of birds, well after the origin of flight and respiratory innovations.

Concepts: Evolution, Bird, Larynx, Geology, Cretaceous, Fossil, Paleontology, Dinosaur

30

Patients who require positive pressure ventilation through a tracheostomy are unable to phonate due to the inflated tracheostomy cuff. Whilst a speaking valve (SV) can be used on a tracheostomy tube, its use in ventilated ICU patients has been inhibited by concerns regarding potential deleterious effects to recovering lungs. The objective of this study was to assess end expiratory lung impedance (EELI) and standard bedside respiratory parameters before, during and after SV use in tracheostomised patients weaning from mechanical ventilation.

Concepts: Pulmonology, Lung, Pneumonia, Respiratory physiology, Larynx, Mucus, Pneumothorax, Vertebrate trachea

28

Introduction: The recurrent laryngeal nerve can be injured during surgery. This study investigated recurrent laryngeal nerve reinnervation. Objective: To study the short-term effects of primary anastomosis of the recurrent laryngeal nerve, by laryngeal electromyography and histopathological analysis, in a rabbit model. Method: Twenty Zealand rabbits underwent either right recurrent laryngeal nerve (1) transection with excision of 1 cm or (2) transection and end-to-end primary anastomosis. Vocal fold movements, laryngeal electromyography results and histological changes were recorded. Results: Vocal fold analysis showed a paramedian vocal fold in both groups, with perceptible vibratory movements in group two. Electromyography revealed total denervation potentials in group one, but denervation and regeneration signs in group two. Histopathologically, hyperkeratosis and parakeratosis of the vocal fold mucosa were seen in group one, and signs of parakeratosis and hyperplasia in group two. Conclusion: Even under ideal conditions for primary recurrent laryngeal nerve anastomosis, a return to normal muscle function is unlikely. However, such anastomosis prevents muscle atrophy, and should be performed as soon as possible. The degree of nerve recovery is associated with the number, amplitude and myelination level of fibrils returning to the original motor end-plaque.

Concepts: Surgery, Muscle, Anatomical pathology, Histopathology, Muscle atrophy, Larynx, Recurrent laryngeal nerve, Superior laryngeal nerve

27

Dysphagia is a symptom of swallowing dysfunction that occurs between the mouth and the stomach. Although oropharyngeal dysphagia is a highly prevalent condition (occurring in up to 50% of elderly people and 50% of patients with neurological conditions) and is associated with aspiration, severe nutritional and respiratory complications and even death, most patients are not diagnosed and do not receive any treatment. By contrast, oesophageal dysphagia is less prevalent and less severe, but with better recognized symptoms caused by diseases affecting the enteric nervous system and/or oesophageal muscular layers. Recognition of the clinical relevance and complications of oesophageal and oropharyngeal dysphagia is growing among health-care professionals in many fields. In addition, the emergence of new methods to screen and assess swallow function at both the oropharynx and oesophagus, and marked advances in understanding the pathophysiology of these conditions, is paving the way for a new era of intensive research and active therapeutic strategies for affected patients. Indeed, a unified field of deglutology is developing, with new professional profiles to cover the needs of all patients with dysphagia in a nonfragmented way.

Concepts: Disease, Muscle, Stomach, Larynx, Esophagus, Dysphagia, Swallowing, Oropharyngeal dysphagia

27

The respiratory system, which consists of the lungs, trachea and associated vasculature, is essential for terrestrial life. In recent years, extensive progress has been made in defining the temporal progression of lung development, and this has led to exciting discoveries, including the derivation of lung epithelium from pluripotent stem cells and the discovery of developmental pathways that are targets for new therapeutics. These discoveries have also provided new insights into the regenerative capacity of the respiratory system. This Review highlights recent advances in our understanding of lung development and regeneration, which will hopefully lead to better insights into both congenital and acquired lung diseases.

Concepts: Pulmonology, Blood, Developmental biology, Stem cell, Heart, Larynx, Mucus, Vertebrate trachea

27

The present study aims to evaluate the degree of anterior-posterior and medial supraglottic laryngeal compression in healthy singers of different voice classifications while singing different pitches, loudness, and phonatory tasks.

Concepts: Human voice, Larynx, Singing, Opera, Vocal range, Head voice, Chest voice, Whistle register