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The Laryngoscope Oct 2023The purpose of this study was to determine whether automated estimates of vocal creak would differentiate speakers with adductor laryngeal dystonia (AdLD) from speakers...
OBJECTIVE
The purpose of this study was to determine whether automated estimates of vocal creak would differentiate speakers with adductor laryngeal dystonia (AdLD) from speakers with muscle tension dysphonia (MTD) and speakers without voice disorders.
METHODS
Sixteen speakers with AdLD, sixteen speakers with MTD, and sixteen speakers without voice disorders were recorded in a quiet environment reading aloud a standard paragraph. An open-source creak detector was used to calculate the percentage of creak (% creak) in each of the speaker's six recorded sentences.
RESULTS
A Kruskal-Wallis one-way analysis of variance revealed a statistically significant effect of group on the % creak with a large effect size. Pairwise Wilcoxon tests revealed a statistically significant difference in % creak between speakers with AdLD and controls as well as between speakers with AdLD and MTD. Receiver operating characteristic curve analyses indicated that % creak differentiated AdLD from both controls and speakers with MTD with high sensitivity and specificity (area under the curve statistics of 0.94 and 0.86, respectively).
CONCLUSION
Percentage of creak as calculated by an automated creak detector may be useful as a quantitative indicator of AdLD, demonstrating the potential for use as a screening tool or to aid in a differential diagnosis.
LEVEL OF EVIDENCE
3 Laryngoscope, 133:2687-2694, 2023.
Topics: Humans; Dysphonia; Muscle Tonus; Dystonia; Voice Quality; Voice; Laryngeal Muscles
PubMed: 36715109
DOI: 10.1002/lary.30588 -
Biomechanics and Modeling in... Aug 2023Neck muscles play important roles in various physiological tasks, including swallowing, head stabilization, and phonation. The mechanisms by which neck muscles influence...
Neck muscles play important roles in various physiological tasks, including swallowing, head stabilization, and phonation. The mechanisms by which neck muscles influence phonation are not well understood, with conflicting reports on the change in fundamental frequency for ostensibly the same neck muscle activation scenarios. In this work, we introduce a reduced-order muscle-controlled vocal fold model, comprising both intrinsic muscle control and extrinsic muscle effects. The model predicts that when the neck muscles pull the thyroid cartilage in the superior-anterior direction (with a sufficiently large anterior component), inferior direction, or inferior-anterior direction, tension in the vocal folds increases, leading to fundamental frequency rise during sustained phonation. On the other hand, pulling in the superior direction, superior-posterior direction, or inferior-posterior direction (with a sufficiently large posterior component) tends to decrease vocal fold tension and phonation fundamental frequency. Varying the pulling force location alters the posture and phonation biomechanics, depending on the force direction. These findings suggest potential roles of particular neck muscles in modulating phonation fundamental frequency, with implications for vocal hyperfunction.
Topics: Laryngeal Muscles; Phonation; Vocal Cords; Biomechanical Phenomena; Electric Stimulation
PubMed: 37169957
DOI: 10.1007/s10237-023-01724-3 -
Current Opinion in Otolaryngology &... Jun 2009Feeding competency is a frequent and serious challenge to the neonatal intensive care unit survivors and to the physician-provider-parent teams. The urgency of effective... (Review)
Review
PURPOSE OF REVIEW
Feeding competency is a frequent and serious challenge to the neonatal intensive care unit survivors and to the physician-provider-parent teams. The urgency of effective assessment and intervention techniques is obviated to promote safe swallow, as attainment of oral feeding for the preterm infant/newborn is one of the prerequisites for hospital discharge. If left unresolved, feeding problems may persist into early childhood and may require management by pediatric gastroenterologists and feeding therapists. This review highlights studies aimed at understanding the motor control and development of nonnutritive and nutritive suck, swallow, and coordination with respiration in preterm populations.
RECENT FINDINGS
Functional linkages between suck-swallow and swallow-respiration manifest transitional forms during late gestation and can be delayed or modified by sensory experience and/or disease processes. Moreover, brainstem central pattern generator (CPG) networks and their neuromuscular targets attain functional status at different rates, which ultimately influences cross-system interactions among individual CPGs. Entrainment of trigeminal primary afferents to activate the suck CPG is one example of a clinical intervention to prime cross-system interactions among ororhythmic pattern generating networks in the preterm and term infants.
SUMMARY
The genesis of within-system CPG control for rate and amplitude scaling matures differentially for suck, mastication, swallow, and respiration. Cross-system interactions among these CPGs represent targets of opportunity for new interventions that optimize experience-dependent mechanisms to promote robust ororhythmic patterning and safe swallows among preterm infants.
Topics: Afferent Pathways; Animals; Brain Stem; Bronchopulmonary Dysplasia; Cerebellum; Deglutition; Disease Models, Animal; Gestational Age; Humans; Infant, Newborn; Infant, Premature, Diseases; Laryngeal Muscles; Motor Cortex; Nerve Net; Pharynx; Pneumonia, Aspiration; Pulmonary Ventilation; Respiratory Distress Syndrome, Newborn; Risk Factors; Somatosensory Cortex; Sucking Behavior; Trigeminal Nerve
PubMed: 19369871
DOI: 10.1097/MOO.0b013e32832b36fe -
American Journal of Veterinary Research Jul 2022To determine whether muscle-sparing laryngoplasty results in fewer changes in swallowing function compared to standard surgical treatment for laryngeal paralysis.
OBJECTIVE
To determine whether muscle-sparing laryngoplasty results in fewer changes in swallowing function compared to standard surgical treatment for laryngeal paralysis.
ANIMALS
12 clinically normal sexually intact male Beagles.
PROCEDURES
Group A dogs (n = 4) had a standard approach to the larynx, with left arytenoid cartilage lateralization. Group B dogs (n = 4) had a muscle-sparing laryngoplasty performed with the thyropharyngeus muscle fibers bluntly separated, and the cricoarytenoideus dorsalis muscle spared. Pre- and 24-hour postoperative fluoroscopic swallowing studies were performed and graded. Larynges were harvested after humane euthanasia, and glottic area was measured. Group C dogs (n = 4) acted as controls, with surgical dissection ending lateral to the thyropharyngeus muscle, arytenoid lateralization not performed, and the dogs not euthanized. The study was performed between October 15, 2011 and May 15, 2021.
RESULTS
Changes in pharyngeal and upper esophageal sphincter function were not detected in any group. There was no difference in glottic area between treatment groups. Aspiration of liquid was not a consistent finding. Two dogs in each treatment group developed moderate to severe cervical esophageal paresis. This did not occur in control dogs.
CLINICAL RELEVANCE
We found no evidence to support our hypothesis that muscle-sparing laryngoplasty results in less severe changes in swallowing function compared to a standard technique. The cervical esophageal paresis identified in both treatment groups could increase the risk of postoperative aspiration pneumonia in dogs treated for laryngeal paralysis via a lateral approach to the larynx. Further study to determine the frequency, cause, and duration of esophageal dysfunction is warranted.
Topics: Animals; Arytenoid Cartilage; Dog Diseases; Dogs; Glottis; Laryngeal Muscles; Larynx; Male; Paresis; Vocal Cord Paralysis
PubMed: 35895756
DOI: 10.2460/ajvr.22.03.0040 -
Journal of Anatomy Aug 2011The larynx serves respiratory, protective, and phonatory functions. The motor and sensory innervation to the larynx controlling these functions is provided by the...
The larynx serves respiratory, protective, and phonatory functions. The motor and sensory innervation to the larynx controlling these functions is provided by the superior laryngeal nerve (SLN) and the recurrent laryngeal nerve (RLN). Classical studies state that the SLN innervates the cricothyroid muscle and provides sensory innervation to the supraglottic cavity, whereas the RLN supplies motor innervation to the remaining intrinsic laryngeal muscles and sensory innervation to the infraglottic cavity, but recent data suggest a more complex anatomical and functional organisation. The current neuroanatomical tracing study was undertaken to provide a comprehensive description of the central brainstem connections of the axons within the SLN and the RLN, including those neurons that innervate the larynx. The study has been carried out in 41 adult male Sprague-Dawley rats. The central projections of the laryngeal nerves were labelled following application of biotinylated dextran amines onto the SLN, the RLN or both. The most remarkable result of the study is that in the rat the RLN does not contain any afferent axons from the larynx, in contrast to the pattern observed in many other species including man. The RLN supplied only special visceromotor innervation to the intrinsic muscles of the larynx from motoneurons in the nucleus ambiguus (Amb). All the afferent axons innervating the larynx are contained within the SLN, and reach the nucleus of the solitary tract. The SLN also contained secretomotor efferents originating from motoneurons in the dorsal motor nucleus of the vagus, and special visceral efferent fibres from the Amb. In conclusion, the present study shows that in the rat the innervation of the larynx differs in significant ways from that described in other species.
Topics: Animals; Brain Stem; Dextrans; Laryngeal Muscles; Laryngeal Nerves; Male; Rats; Rats, Sprague-Dawley; Solitary Nucleus; Vagus Nerve
PubMed: 21599662
DOI: 10.1111/j.1469-7580.2011.01390.x -
Cells, Tissues, Organs 2003Mammalian skeletal muscle fibers can be classified into functional types by the heavy chain (MyHC) and light chain (MyLC) isoforms of myosin (the primary motor protein)... (Comparative Study)
Comparative Study Review
Mammalian skeletal muscle fibers can be classified into functional types by the heavy chain (MyHC) and light chain (MyLC) isoforms of myosin (the primary motor protein) that they contain. Most human skeletal muscle contains fiber types and myosin isoforms I, IIA and IIX. Some highly specialized muscle fibers in human extraocular and jaw-closing muscles express either novel myosins or unusual combinations of isoforms of unknown functional significance. Extrinsic laryngeal muscles may express the extraocular MyHC isoform for rapid contraction and a tonic MyHC isoform for slow tonic contractions. In jaw-closing muscles, fiber phenotypes and myosin expression have been characterized as highly unusual. The jaw-closing muscles of most carnivores and primates have tissue-specific expression of the type IIM or 'type II masticatory' MyHC. Human jaw-closing muscles, however, do not contain IIM myosin. Rather, they express myosins typical of developing or cardiac muscle in addition to type I, IIA and IIX myosins, and many of their fibers are hybrids, expressing two or more isoforms. Fiber morphology is also unusual in that the type II fibers are mostly of smaller diameter than type I. By combining physiological and biochemical techniques it is possible to determine the maximum velocity of unloaded shortening (V(o)) of an individual skeletal muscle fiber and subsequently determine the type and amount of myosin isoform. When analyzed, some laryngeal fibers shorten at much faster rates than type II fibers from limb and abdominal muscle. Yet some type I fibers in masseter show an opposite trend towards speeds 10-fold slower than type I fibers of limb muscle. These unusual shortening velocities are most probably regulated by MyHC isoforms in laryngeal fibers and by MyLC isoforms in masseter. For the jaw-closing muscles, this finding represents the first case in human muscle of physiological regulation of kinetics by light chains. Together, these results demonstrate that, compared to other skeletal muscles, cranial muscles have a wider repertoire of contractile protein expression and function. Molecular techniques for reverse transcription of mRNA and amplification by polymerase chain reaction have been applied to typing of single fibers isolated from limb muscles, successfully identifying pure type I, IIA and IIX and hybrid type I/IIA and IIA/IIX fibers. This demonstrates the potential for future studies of the regulation of gene expression in jaw-closing and laryngeal muscles, which have such a variety of complex fiber types fitting them for their roles in vivo.
Topics: Animals; Humans; Laryngeal Muscles; Masseter Muscle; Rectus Abdominis
PubMed: 12784043
DOI: 10.1159/000070576 -
Brain Sciences Nov 2023Laryngeal dystonia (LD), known or termed as spasmodic dysphonia, is a rare movement disorder with an unknown cause affecting the intrinsic laryngeal muscles.... (Review)
Review
Laryngeal dystonia (LD), known or termed as spasmodic dysphonia, is a rare movement disorder with an unknown cause affecting the intrinsic laryngeal muscles. Neurophysiological studies point to perturbed inhibitory processes, while conventional genetic studies reveal fragments of genetic architecture in LD. The study's aims are to (1) describe transcranial magnetic stimulation (TMS) methodology for studying the functional integrity of the corticospinal tract by stimulating the primary motor cortex (M1) for laryngeal muscle representation and recording motor evoked potentials (MEPs) from laryngeal muscles; (2) evaluate the results of TMS studies investigating the cortical silent period (cSP) in LD; and (3) present the standard treatments of LD, as well as the results of new theoretical views and treatment approaches like repetitive TMS and laryngeal vibration over the laryngeal muscles as the recent research attempts in treatment of LD. Neurophysiological findings point to a shortened duration of cSP in adductor LD and altered cSP duration in abductor LD individuals. Future TMS studies could further investigate the role of cSP in relation to standard laryngological measures and treatment options. A better understanding of the neurophysiological mechanisms might give new perspectives for the treatment of LD.
PubMed: 38002550
DOI: 10.3390/brainsci13111591 -
Ear, Nose, & Throat Journal May 2021To investigate the value of diffusion tensor imaging (DTI) in the evaluation of vocal fold tissue microstructure after recurrent laryngeal nerve (RLN) injury.
OBJECTIVE
To investigate the value of diffusion tensor imaging (DTI) in the evaluation of vocal fold tissue microstructure after recurrent laryngeal nerve (RLN) injury.
METHODS
Six canines were divided into 2 groups: a unilateral vocal fold paralysis group (n = 4) and a control group (n 2). The RLN was cut in the unilateral vocal fold paralysis group, and no intervention was applied in the control group. After 4 months, the canines' larynges were removed and placed in a small animal magnetic resonance imaging (MRI) system (9.4T BioSpec MRI; Bruker, Germany). After scanning, the vocal folds were isolated, sectioned, and stained. The slides were then analyzed for the cross-sectional area and muscle fiber density through feature extraction technology. Pearson correlation analysis was performed on the DTI scan and histological section extraction results.
RESULTS
In the vocal fold muscle layer, the fractional anisotropy (FA) of the unilateral RLN injury group was higher than that of the control group, and the Tensor Trace was lower than that of the control group. This difference was statistically significant, < .05. In the lamina propria, the FA of the unilateral RLN injury group was lower than that of the control group, > .05, and the Tensor Trace was lower than that of the control group, < .05. The muscle fiber cross-sectional area of the RLN injury group was significantly smaller than the control group with statistical significance, < .05, and the density of muscle fibers was lower, < .05. The correlation coefficient between FA and the cross-sectional area was -0.838, = .002, and .726; = .017 between Tensor Trace and the cross-sectional area.
CONCLUSION
Diffusion tensor imaging is an effective method to assess the changes in the microstructure of atrophic vocal fold muscle tissue after RLN injury.
Topics: Animals; Anisotropy; Diffusion Tensor Imaging; Dogs; Humans; Laryngeal Muscles; Recurrent Laryngeal Nerve Injuries; Vocal Cord Paralysis; Vocal Cords
PubMed: 31550925
DOI: 10.1177/0145561319874721 -
Otolaryngologia Polska = the Polish... Dec 2018Hyperfunctional dysfunction is one of the most common functional dysphonia, cha-racterized by voice insufficiency with excessive tightening of the muscles inside and...
INTRODUCTION
Hyperfunctional dysfunction is one of the most common functional dysphonia, cha-racterized by voice insufficiency with excessive tightening of the muscles inside and outside the larynx during phonation. To make the treatment process more effective, new ways of rehabilitation are constantly being sought and developed. The aim of this work is to evaluate the effectiveness of laryngotaping - an innovative method of taping around the larynx and neck muscles.
MATERIAL AND METHOD
10 patients with diagnosed hyperfunctional dysphonia participated in the study. Using the kinesiotaping principles, for 7 days, the suprahyoid and infrahyoid muscles, ster-nocleidomastoid muscles as well as the thyroid cartilage were taped. Before and after the therapy, the patients completed the VHI voice self-evaluation questionnaire. The evaluation of the larynx according to the L. Mathienson scale was also assessed palpation.
RESULTS
Analyzing the results of the VHI questionnaire and evaluation of palpation evaluation of the larynx before and after the therapy, statistically significant differences were observed. The results on average decreased by half, which is the desired effect of therapy.
DISCUSSION
The results confirm the positive impact of kinesiotaping around the larynx. However, more research is needed on a larger group of patients to fully evaluate the therapeutic effect.
CONCLUSIONS
1. Laryngotaping is an effective way to normalize muscle tone, and thus to improve the quality of the voice. 2. The presented studies require continuation, however, positive reception of the introduced therapy by patients encourages further research on a larger group of patients.
Topics: Athletic Tape; Dysphonia; Female; Humans; Laryngeal Muscles; Larynx; Male; Middle Aged; Treatment Outcome; Voice Quality; Voice Training
PubMed: 30919823
DOI: 10.5604/01.3001.0012.7890 -
Toxins Jul 2022Spasmodic dysphonia (SD) is a rare neurological disorder that impairs phonatory function by triggering involuntary and intermittent contractions of the intrinsic... (Review)
Review
Spasmodic dysphonia (SD) is a rare neurological disorder that impairs phonatory function by triggering involuntary and intermittent contractions of the intrinsic laryngeal muscles. SD is classified into three types: adductor SD (AdSD), abductor SD (AbSD), and mixed SD. Of these, AdSD accounts for 90-95% of disease; younger females are predominantly affected. Botulinum toxin injection into the laryngeal muscles is safe, minimally invasive, and very effective. Here, we review the history of clinical research for SD conducted in Japan. The first use of botulinum toxin injection therapy to treat SD in Japan was by Kobayashi et al. in 1989. The group developed an objective mora (syllable) method to evaluate SD severity. Recently, we conducted a placebo-controlled, randomized, double-blinded clinical trial of botulinum toxin therapy for AdSD and an open-label trial for AbSD to obtain the approval of such therapy by the Japanese medical insurance system. The mora method revealed significant voice improvement and the evidence was of high quality. Additionally, a clinical trial of type 2 thyroplasty using titanium bridges confirmed the efficacy and safety of such therapy. These studies broadened the SD treatment options and have significantly benefited patients.
Topics: Botulinum Toxins; Botulinum Toxins, Type A; Dysphonia; Female; Humans; Injections; Japan; Laryngeal Muscles; Randomized Controlled Trials as Topic; Treatment Outcome
PubMed: 35878189
DOI: 10.3390/toxins14070451