Phonetogram Changes for Trained Singers Over a Nine-Month Period of Vocal Training

Professional vocalists encounter demands requiring voluntary control of phonation, while utilizing a considerable range of frequency and intensity. These quantifiable acoustic events can be measured and represented in a phonetogram. Previous research has compared the phonetograms of trained and untrained voices and found significant differences between these groups. This study was designed to assess the effects of vocal training for singers over a period of nine months. Phonetogram contour changes were examined, with the primary focus on expansion of frequency range and/or intensity control. Twenty-one first-year, master's level, vocal music students, who were engaged in an intensive vocal performance curriculum, participated in this study. Following nine months of vocal training, significant differences were revealed in the subjects' mean frequency range and minimum vocal intensity across frequency levels. There was no significant difference for the mean maximum vocal intensity across frequency levels following vocal training.     

Fibronectin: An Interesting Vocal Fold Protein

A great deal of information is accruing regarding the function of the extracellular matrix. Once thought to be simply a structural entity to surround cells, it is now known to do much more. Fibronectin in particular has received specific attention. Fibronectin is a ubiquitous glycoprotein found most abundantly in the extracellular matrix of regenerating, healing, and embryonic tissue. Vast evidence supports the fact that fibronectin participates in many diverse functions throughout the body that are relevant to vocal fold biology. This article introduces the structure of fibronectin and its isoforms and provides an introduction to some of the many functions it plays. It also reviews the evidence about fibronectin's place in vocal folds and vocal fold pathology. It discusses fibronectin's presence in vocal nodules, vocal polyps, vocal scarring, and Reinke's edema, and reviews the data on its role in mucosal wave impairment. Lastly, it discusses preliminary microarray data that show gene expression for fibronectin to be upregulated in true vocal folds when compared to false vocal folds.     

Dynamic glottal pressures in an excised hemilarynx model

During phonation, air pressures act upon the vocal folds to help maintain their oscillation. The air pressures vary dynamically along the medial surface of the vocal folds, although no live human or excised studies have shown how those pressure profiles vary in time. The purpose of this study was to examine time-dependent glottal pressure profiles using a canine hemilarynx approach. The larynx tissue was cut in the midsaggital plane from the top to about 5 mm below the vocal folds. The right half was replaced with a Plexiglas pane with imbedded pressure taps. Simultaneous recordings were made of glottal pressure signals, subglottal pressure, particle velocity, and average airflow at various levels of adduction. The data indicate that the pressures in the glottis (on the Plexiglas) vary both vertically and longitudinally throughout the phonatory cycle. Pressures vary most widely near the location of maximum vibratory amplitude, and can include negative pressures during a portion of the cycle. Pressures anterior and posterior to the maximum amplitude location may have less variation and may remain positive throughout the cycle, giving rise to a new concept called dynamic bidirectional pressure gradients in the glottis. This is an important concept that may relate strongly to tissue health as well as basic oscillatory mechanics.     

The frequency of hard glottal attacks in patients with muscle tension dysphonia, unilateral benign masses and bilateral benign masses

Hard or abrupt glottal attack (HGA) is one of the vocal behaviors often associated with benign lesion of the vocal folds. This study was designed to determine whether the frequency of HGA was different in hyperfunctional voice patients with and without vocal fold masses. One hundred and forty-seven subjects were studied. All subjects received a complete otolaryngological evaluation including strobovideolaryngoscopy, objective voice measures, and evaluation by a speech-language pathologist. Thirty-two patients were diagnosed with muscle tension dysphonia (19 male, 13 female) without vocal fold masses. Fifty-seven patients were diagnosed with unilateral vocal fold masses (29 male, 28 female), most of which were cysts. Fifty-eight patients were diagnosed with bilateral vocal fold masses (13 male, 45 female). Of the 45 females with bilateral vocal fold masses. 26 had a vocal cyst and reactive nodule and 19 had bilateral vocal fold nodules. The control group was balanced and matched based on sex and on percentage of singers and nonsingers. It consisted of 49 subjects with no vocal fold pathology (20 male, 29 female). The group was composed of professional speakers, singers, and nonprofessional speakers. All voice disordered groups demonstrated higher frequencies of HGA than the control group. Differences were found between the male and female subjects in this study. No differences were found between the various disorders. Differences were also found between the subgroups of bilateral masses, where the bilateral nodules group presented a higher frequency of HGA than the cyst and contralateral reactive nodule.     

Effects of a vocally fatiguing task and systemic hydration on phonation threshold pressure

Phonation threshold pressure (PTP), effort for speaking, and vibratory closure pattern were assessed in 4 women with normal untrained voices after 2 hours of loud reading. PTP generally increased after this vocally fatiguing task at conversational pitch and 10%, 50%, and especially 80% of the pitch range. Increased systemic hydration by drinking water appeared to attenuate and/or delay the elevation of PTP for 3 subjects, at least at the highest pitch tested. Effort for speaking increased consistently throughout the loud reading task and subsequently decreased after 15 minutes of vocal silence. Upon videostroboscopic examination of the larynx, 3 subjects demonstrated spindle-shaped vibratory closure patterns on occasion after loud reading. The results provide preliminary support for increasing water consumption to reduce or delay some vocal-function changes after prolonged loud phonation in untrained speakers.     

Studying edge effects near rectangular mine workings weakened by a crack

Edge effects in a rock mass near a system of periodic mine workings crossed by a crack (fold fault) are considered. The stress state near the mine workings is determined by solving an elastic problem using the piecewise-homogeneous medium model. The original differential problem is reduced to a discrete problem based on the concept of a base scheme. Methods are proposed to solve the discrete problem, and the issue of optimizing the numerical analysis is discussed. The stress distribution around mine workings is analyzed. The stress isolines that represent the boundaries of edge effect zones and indicate their maximum decay length are plotted __________ Translated from Prikladnaya Mekhanika, Vol. 44, No. 1, pp. 74–78, January 2008.     

走滑式断层地震的折迭突变模型

利用过势函数微分形式的途径,计入远场外力功的影响,对走滑式断层地震机制进行分析．研究表明:突变理论中折迭突变模型展示的性状,与走滑式断层地震的主要特征之间一一对应．折迭突变可对包括震前、震后围岩-断层系统稳定性描述在内的断层失稳起、终点位置、断层失稳错距等作出描述．给出3种性状可相互印证的断层失稳围岩弹性能释放量图解．走滑式断层地震强度与围岩压力及围岩断层的刚度比等有关,围岩压力大、刚度比小、主切应力轴与发震断层面夹角大,则地震强度大．     

Deviant Vocal Fold Vibration as Observed During Videokymography: The Effect on Voice Quality

Videokymographic images of deviant or irregular vocal fold vibration, including diplophonia, the transition from falsetto to modal voice, irregular vibration onset and offset, and phonation following partial laryngectomy were compared with the synchronously recorded acoustic speech signals. A clear relation was shown between videokymographic image sequences and acoustic speech signals, and the effect of irregular or incomplete vocal fold vibration patterns was recognized in the amount of perceived breathiness and roughness and by the harmonics-to-noise ratio in the speech signal. Mechanisms causing roughness are the presence of mucus, phase differences between the left and right vocal fold, and short-term frequency and amplitude modulation. It can be concluded that the use of simultaneously recorded videokymographic image sequences and speech signals contributes to the understanding of the effect of irregular vocal fold vibration on voice quality.     

Laryngeal Myasthenia Gravis: Report of 40 Cases

Myasthenia gravis, an autoimmune disorder of the neuromuscular junction, is usually recognized because of ocular complaints or generalized weakness. We report a series of 40 patients who presented with dysphonia as their initial and primary complaint. Diagnostic testing included strobovideolaryngoscopy, electromyography (EMG) with repetitive stimulation and Tensilon testing, and laboratory and radiographic evaluation. Strobovideolaryngoscopy most commonly revealed fluctuating impairment of vocal fold mobility, either unilateral or bilateral. EMG detected evidence of neuromuscular junction abnormalities in all patients. Only one patient had evidence of antiacetylcholine receptor (ACh-R) antibodies, but many other abnormalities suggestive of autoimmune dysfunction were present. Pyridostigmine therapy was initiated in 34 patients but was not tolerated in 4. Of the remaining 30 patients, 23 reported improvement of symptoms. We conclude that myasthenia gravis can present with symptoms confined primarily to the larynx and should be included in the differential diagnosis of dysphonia.     

Minifenestration Type I Thyroplasty Using an Expanded Polytetrafluoroethylene Implant

Several methods have been used to treat laryngeal incompetence, but no ideal technique has been identified. This paper describes a clinical experience with minifenestration type I thyroplasty using a new device made of expanded polytetrafluoroethylene (ePTFE). The device, a thin ribbon of ePTFE, is inserted through a 4-mm fenestration to produce vocal fold medialization. At our center, 26 of these devices have been implanted in the past 3 years. Good or satisfactory results were achieved in 96% of cases. Advantages of this technique include easy insertion of the implant, nominal cost and biocompatibility of the ePTFE device, ready availability of all instruments required for the procedure, and elimination of the need to perform arytenoid adduction.