Vocal cord dysfunction: dealing with aggressivity.
(73/491)
QUESTIONS UNDER STUDY: Vocal cord dysfunction (VCD) is characterised by recurrent attacks of paradoxical adduction of the vocal cords during inspiration, accompanied clinically by dyspnoea attacks with inspiratory stridor lasting between minutes and hours. The aim of the study is to evaluate the self-perception of patients suffering from VCD and how they deal with aggressivity. METHODS: The Giessen Test (GT) and the Picture Frustration Test (PFT) were used on 6 patients with VCD. RESULTS: Five variables show significant differences between the patients with VCD and the values of the normative groups. VCD-patients show an idealized image of themselves, ie relaxed, open, sociable, and capable of devotion. They do not reject accusations against them by others and rarely make self-criticism. In conflicts they behave passively, thus blocking their expression of aggressivity. CONCLUSIONS: In many cases organic disposition and trigger stimuli are thought to be responsible for provoking dyspnoea attacks in VCD. However, the self-perception of patients and their way of dealing with aggressivity strongly suggests that psychosocial factors play a great role in the development of VCD. This requires not only symptom-orientated therapy but also psychological counselling. (+info)
Animal communication: big talkers and small talk.
(74/491)
Vocal tract resonances, known as formants, are important perceptual cues for the identification of human speech and animal calls. A recent study shows that monkeys can also use formants to determine the age and size of the monkey producing a call. (+info)
Refinements in modeling the passive properties of laryngeal soft tissue.
(75/491)
The nonlinear viscoelastic passive properties of three canine intrinsic laryngeal muscles, the lateral cricoarytenoid (LCA), the posterior cricoarytenoid (PCA), and the interarytenoid (IA), were fit to the parameters of a modified Kelvin model. These properties were compared with those of the thyroarytenoid (TA) and cricothyroid (CT) muscles, as well as previously unpublished viscoelastic characteristics of the human vocal ligament. Passive parameters of the modified Kelvin model were summarized for the vocal ligament, mucosa, and all five laryngeal muscles. Results suggest that the LCA, PCA, and IA muscles are functionally different from the TA and CT muscles in their load-bearing capacity. Furthermore, the LCA, PCA, and IA have a much larger stress-strain hysteresis effect than has been previously reported for the TA and CT or the vocal ligament. The variation in this effect suggests that the connective tissue within the TA and CT muscles is somehow similar to the vocal ligament but different from the LCA, PCA, or IA muscles. Further demonstrating the potential significance of grouping tissues in the laryngeal system by functional groups in the laryngeal system was the unique finding that, over their working elongation range, the LCA and PCA were nearly as exponentially stiff as the vocal ligament. This paper was written in conjunction with an online technical report (http://www.ncvs.org/ncvs/library/tech) in which comprehensive muscle data and sensitivity analysis, as well as downloadable data files and computer scripts, are made available. (+info)
Human brain activation during phonation and exhalation: common volitional control for two upper airway functions.
(76/491)
Phonation is defined as a laryngeal motor behavior used for speech production, which involves a highly specialized coordination of laryngeal and respiratory neuromuscular control. During speech, brief periods of vocal fold vibration for vowels are interspersed by voiced and unvoiced consonants, glottal stops and glottal fricatives (/h/). It remains unknown whether laryngeal/respiratory coordination of phonation for speech relies on separate neural systems from respiratory control or whether a common system controls both behaviors. To identify the central control system for human phonation, we used event-related fMRI to contrast brain activity during phonation with activity during prolonged exhalation in healthy adults. Both whole-brain analyses and region of interest comparisons were conducted. Production of syllables containing glottal stops and vowels was accompanied by activity in left sensorimotor, bilateral temporoparietal and medial motor areas. Prolonged exhalation similarly involved activity in left sensorimotor and temporoparietal areas but not medial motor areas. Significant differences between phonation and exhalation were found primarily in the bilateral auditory cortices with whole-brain analysis. The ROI analysis similarly indicated task differences in the auditory cortex with differences also detected in the inferolateral motor cortex and dentate nucleus of the cerebellum. A second experiment confirmed that activity in the auditory cortex only occurred during phonation for speech and did not depend upon sound production. Overall, a similar central neural system was identified for both speech phonation and voluntary exhalation that primarily differed in auditory monitoring. (+info)
Occupational vocal cord dysfunction due to exposure to wood dust and xerographic toner.
(77/491)
OBJECTIVES: Vocal cord dysfunction is a poorly understood entity that is often misdiagnosed as asthma. Both irritant and non-irritant vocal cord dysfunction have been described. This report presents two cases of irritant vocal cord dysfunction secondary to specific environmental exposure, the first to iroko and western red cedar wood (a carpenter) and the second to xerographic printing toner (a secretary). METHODS: Several tests were performed, including chest radiographs, measurements of total serum immunoglobulin E, skin prick tests with common pneumoallergens (as well as iroko and western red cedar in the first case), pulmonary function studies, methacholine challenge testing, specific inhalation challenge performed with suspected agents in a single-blinded fashion, and peak expiratory flow testing and fiberoptic rhinolaryngoscopy (in case 1). RESULTS: During the specific inhalation challenge, the patients showed dysphonia, chest tightness, inspiratory stridor, and flattening of the inspiratory limb of the maximum flow-volume loop in spirometry, with no significant decreases in the level of forced expiratory volume in 1 second; fiberoptic rhinolaryngoscopy confirmed the diagnosis of vocal cord dysfunction in case 1. CONCLUSIONS: It is important to know that agents that can cause occupational asthma can also cause vocal cord dysfunction. The mechanisms by which these agents produce vocal cord dysfunction are unknown. The differences in the clinical presentation of the patients described relative to the reported cases suggest that more than one pathophysiological mechanism may be implicated in the genesis of this entity. (+info)
Discovery of a low frequency sound source in Mysticeti (baleen whales): anatomical establishment of a vocal fold homolog.
(78/491)
The mechanism of mysticete (baleen whale) vocalization has remained a mystery. Vocal folds (true vocal "cords"), the structures responsible for sound production in terrestrial mammals, were thought to be absent in whales. This study tests the hypothesis that the mysticete larynx possesses structures homologous to vocal folds and that they are capable of sound generation. Laryngeal anatomy was examined in 37 specimens representing 6 mysticete species. Results indicate the presence of a U-shaped fold (U-fold) in the lumen of the larynx. The U-fold is supported by arytenoid cartilages, controlled by skeletal muscles innervated by the recurrent laryngeal nerve, is adjacent to a diverticulum (laryngeal sac) covered with mucosa innervated by the superior laryngeal nerve, and contains a ligament-conditions that also define the vocal folds of terrestrial mammals and, therefore, supports homology. Unlike the vocal folds of terrestrial mammals, which are perpendicular to airflow, the mysticete U-fold is oriented parallel to airflow. U-fold adduction/abduction and elevation/depression may control airflow, and vibration of its edges may generate sounds. The walls of the laryngeal sac can expand and contract, may serve as a resonant space, and may also propagate vibrations generated by movements of the supporting arytenoid cartilages. The extensive musculature surrounding the laryngeal sac may enable rapid and forceful expulsion of air from the lumen of the sac into other respiratory spaces, or maintain a constant sac volume despite the effects of ambient pressure (e.g., changes during diving or ascent). The size and complexity of the mysticete larynx indicates an organ with multiple functions, including protection during breathing/swallowing, regulation of airflow and pressures in the respiratory spaces, and sound generation. The presence of a vocal fold homolog offers a new insight into both the mechanism of sound generation by mysticetes and the divergent evolution of odontocete and mysticete cetaceans. (+info)
Frequency of transient ipsilateral vocal cord paralysis in patients undergoing carotid endarterectomy under local anesthesia.
(79/491)
BACKGROUND: Especially because of improvements in clinical neurologic monitoring, carotid endarterectomy done under local anesthesia has become the technique of choice in several centers. Temporary ipsilateral vocal nerve palsies due to local anesthetics have been described, however. Such complications are most important in situations where there is a pre-existing contralateral paralysis. We therefore examined the effect of local anesthesia on vocal cord function to better understand its possible consequences. METHODS: This prospective study included 28 patients undergoing carotid endarterectomy under local anesthesia. Vocal cord function was evaluated before, during, and after surgery (postoperative day 1) using flexible laryngoscopy. Anesthesia was performed by injecting 20 to 40 mL of a mixture of long-acting (ropivacaine) and short-acting (prilocaine) anesthetic. RESULTS: All patients had normal vocal cord function preoperatively. Twelve patients (43%) were found to have intraoperative ipsilateral vocal cord paralysis. It resolved in all cases < or =24 hours. There were no significant differences in operating time or volume or frequency of anesthetic administration in patients with temporary vocal cord paralysis compared with those without. CONCLUSION: Local anesthesia led to temporary ipsilateral vocal cord paralysis in almost half of these patients. Because pre-existing paralysis is of a relevant frequency (up to 3%), a preoperative evaluation of vocal cord function before carotid endarterectomy under local anesthesia is recommended to avoid intraoperative bilateral paralysis. In patients with preoperative contralateral vocal cord paralysis, surgery under general anesthesia should be considered. (+info)
A study of the histological behavior of a rabbit vocal fold after a hyaluronic acid injection.
(80/491)
The vocal fold structure is composed of tissues with many cells surrounded by the extra-cellular matrix. One of the most important components of the extra-cellular matrix is Hyaluronic Acid (HA). The aim of the study was to evaluate the inflammatory response of rabbit vocal folds after a local injection of Restylane HA. METHODS: Twelve adult male rabbits randomly received a 0.1 ml injection of Restylane HA in one vocal fold and 0.1 ml of saline in the other vocal fold. The animals were prospectively subdivided into two groups; animals in one group were sacrificed after one week of follow-up and animals in the other group were sacrificed after 3 months. Slides were Hematoxylin-Eosin (HE), Masson Trichromic and Toluidine Blue stained. RESULTS: Hyaluronic Acid was found microscopically in all specimens in both groups. There was more connective tissue surrounding HA, always associated with a mild inflammatory response. The longer exposure time did not increase the intensity of inflammation. Tissue necrosis and foreign body inflammatory reaction were not observed in both groups. CONCLUSION: The study suggests that HA is a good alternative as a filling material in vocal folds when treating glottal insufficiency. (+info)