An asymmetric smooth contour two-mass model for recurrent laryngeal nerve paralysis

Irregular vocal fold vibrations are assumed to be a major cause of hoarseness. A common clinical condition presenting with hoarseness is a unilateral recurrent laryngeal nerve paralysis (RLNP). In order to explain high-speed video recordings of clinical RLNP, RLNP-type vocal fold vibrations are simulated by extending the well known two-mass model (2MM) to an asymmetric smooth-contour two-mass model (SC2MM). Polynomial interpolations form a smooth surface over the lumped elements of the 2MM. Laryngeal asymmetry is accounted for by introduction of an asymmetry coefficient and an anterior commissure angle which models a variable glottal closure insufficiency. Compared to the 2MM, the SC2MM yields a smaller glottal volume flow and is more stable in critical parameter constellations of RLNP-like conditions. It is able to model the vocal fold dynamics during a glottal closure insufficiency.

Musculoskeletal patterns in patients with voice disorders

This study correlated the ear, nose, and throat (ENT) and physiotherapy input on 26 patients who presented with voice problems and were found by the ENT surgeon to have a degree of musculoskeletal issues. It also looked for patterns of musculoskeletal findings. Although all patients referred were found by the physiotherapist to have musculoskeletal abnormalities, the correlation proved to be excellent among the subgroup of performers, but only fair-to-good among the other voice professionals. Certain patterns of musculoskeletal abnormalities were frequently encountered, including a high held larynx, a shortening or contraction of the stylohyoid and sternocleidomastoid muscles, and a weak deep flexor mechanism. In this small group, most patients seemed to improve, although it must be noted that management was not limited to physiotherapy. In summary, physiotherapy input proved helpful in the evaluation and management of this group of patients presenting with voice problems.

Predicting mutational change in the speaking voice of boys

SUMMARY

The authors investigated whether acoustic speaking voice analyses can be used to predict the beginning of mutation in 21 male members of a professional boys' choir. Over a period of 3 years before mutation, children were examined every 3 months by ear, nose, and throat (ENT) and phoniatric specialists. At the same time, the voice was evaluated acoustically using analysis features of the Goettingen Hoarseness Diagram (GHD). Irregularity component and noise component, jitter, shimmer, mean waveform correlation coefficient, and fundamental frequency were determined from recordings of the speaking voice. Significant changes of acoustic features appeared 7 and 5 months before mutation onset, which indicates that vocal function is already restricted 6 months before mutation onset. This acoustic voice analysis is therefore suitable to support the care of the professional singing voice.

Stereotactic radiosurgery for recurrent pleomorphic adenoma invading the skull base--case report--

A 38-year-old man presented with a recurrent pleomorphic adenoma in the parapharyngeal space invading the skull base 19 years after the first operation for a parotid gland tumor. Stereotactic radiotherapy was performed to control the tumor growth using a marginal dose of 8 Gy and maximum dose of 18 Gy with care taken to minimize the dose to nearby structures. The symptoms were reduced within a few months. Magnetic resonance imaging over 5 years showed that the tumor was controlled with no regrowth. Stereotactic radiotherapy is a therapeutic option for the treatment of pleomorphic adenomas.

Correlates of Varying Vocal Fold Adduction Deficiencies in Perception and Production: Methodological and Practical Considerations

In this study the voice characteristics of normal male and female speakers are compared to those of two groups of patients with unilateral vocal fold paralysis. In order to enhance phonation, the patients in the first group compensate for the adduction deficiency which results from paralysis. The patients in the second group do not use compensatory strategies. Sustained vowels [i:, a:, u:] were produced by the speakers and scored for roughness, breathiness and hoarseness (RBH) by 8 raters. Although interrater agreement for RBH scores is only moderate on average, these percepts make consistent distinctions between the three speaker groups. Consistent but different distinctions are made between the three speaker groups for male and female speakers. The results show that male and female speakers should not be pooled in experimental studies of the pathological voice. Our results also indicate that female patients with a compensated unilateral vocal fold paralysis cannot be clinically evaluated solely on the basis of perception, because their voices cannot be distinguished from normal, healthy female speakers, despite their physiological impairment. The group distinctions made on the basis of RBH scores are supported by differences in the acoustic parameters which are derived by automatic analysis of the sustained vowels. Despite identical group distinctions for RBH scores and acoustic parameters, the acoustic basis of the percepts is not straightforward. Different acoustic predictors of the percepts were found for male compared to female speakers. Additionally, interrater differences point towards the presence of perceptual trading relations.

Tracking outcomes after phonosurgery for sulcus vocalis: a case report

Outcomes data after a surgical or behavioral intervention should be tracked until stability is reached. Often it is unclear how long patients should be followed and at what point an outcome can be considered stable. These issues have implications for treatment decision making, efficacy measurement, and the design of research studies. Vocal function data were collected 24 hours before and at 1, 6, and 12 months after phonosurgery for sulcus vocalis. One data series was collected daily during the first month after surgery, providing a unique opportunity to study voice changes in the immediate postoperative period. The different vocal function indices (acoustic, perceptual, videostroboscopic, aerodynamic, psychosocial) demonstrated a general pattern of improvement after intervention; however, they appeared to reach stability at different times. This report reinforces the value of following patients until complete outcome stability.

Vocal fold deposits in autoimmune disease--an unusual cause of hoarseness

The objective of this study was to evaluate the symptoms and clinical characteristics in patients with autoimmune vocal fold deposits. Fourteen patients underwent videolaryngostroboscopic examination and voice recording. Eleven of the 14 patients underwent rheumatological examination. In all cases, endoscopic examination showed transverse white-yellow band lesions in the middle of the membranous portion of the vocal folds. In most cases, the lesions were bilateral but not exactly opposing each other. The most common voice characteristics were instability and intermittent aphonia. Inflammatory disease was present in 10 patients; five of these had rheumatoid arthritis (RA). No immunological signs common for all patients could be found. The histological examination was consistent with rheumatoid nodules. Vocal fold deposits, occurring most often in patients with RA, is an uncommon cause of hoarseness. Because the patients may have hoarseness as their primary symptom, it is important for otolaryngologists to be familiar with this disorder.

[Measurement and interpretation of irregular vocal cord fold vibrations]

BACKGROUND

Irregular vibrations of the vocal folds are regarded as a main reason for the common symptom of hoarseness. With real time resolution, they can only be observed using high speed recording techniques (up to 10,000 images/s).

METHOD

During the last years, we have developed a recording device and image processing software dedicated to the extraction of vocal fold motion curves from the image series. Irregular vibrations can be understood by using Hirano's "body-cover-model": one vocal fold is assumed to act as a system of two coupled oscillators (the vocal muscle and the epithelium, coupled by the connective tissue of Reinke's space).

RESULTS

By applying this biomechanical two-mass model and inversely solving Bernoulli's equation, the driving parameters of the vibration were computed from the high speed image series in selected cases. These parameters, like the subglottal pressure und the bilateral tension of the vocal muscle cannot, in general, be measured directly.

DISCUSSION

From the model, it can be supposed that laryngeal asymmetry (either in mass or tension) is the primary reason causing irregularity. The consequence of asymmetry in the medio-lateral direction are different fundamental frequencies on each side, while asymmetry in the anterior-posterior direction leads to ap-mode vibrations.

[Vowel selection effects on the parameters of acoustic analysis]

OBJECTIVE

To investigate if there is difference about the parameters of acoustic analysis with the different vowel |a|, |i|, |ae| and decide which vowels is best fitted to the acoustic analysis.

METHOD

40 normal and 130 pathologic voice patients accepted acoustic analysis. Each acoustic parameters such as jitter, shimmer, NNE, SDF0, SNR were compared with different vowels.

RESULT

Jitter, shimmer, NNE with |i| were much lower than that with |a| and |ae| in normal cases and light hoarseness group. While the acoustic parameters with |i| were much higher than that with |a| and |ae| in moderate and heavy hoarseness group.

CONCLUSION

|a| and |ae| were the preferred vowels for normal and light hoarseness group, while the |i| could supply some useful suggestion for the moderate and heavy hoarse patients.

Objective assessment of hoarseness by measuring jitter

The objective measurement of hoarseness by measuring 'jitter' (the average percentage pitch-period variation between consecutive pitch-cycles) using an inverse filtering technique is described. Twenty-five patients with a variety of causes of hoarseness were studied, together with five individuals who had mild hoarseness induced by histamine challenge and 12 normal individuals. The mean severity of jitter in the patient group (9.8%) was significantly different from the normals. (1.04%) In addition, there was a significant correlation (R2 = 0.53; P < 0.0001) between jitter and subjective assessment of hoarseness. The mean values of jitter with histamine challenge before and after recovery (1.03%, and 1.18%) were significantly different (P < 0.0001) to the mean maximum value during the challenge (2.64%). These data suggest that jitter is an objective and repeatable measurement of hoarseness-even small changes in hoarseness in individual patients. It is likely to prove most effective for monitoring treatment response.

Dual-probe pH monitoring for the assessment of gastroesophageal reflux in the course of chronic hoarseness in children

The purpose of our study was to assess gastroesophageal reflux (GER) by dual-probe pH monitoring in children suffering from chronic hoarseness for more than six months. Seventeen children (aged between 2 and 12 years, 10 boys and 7 girls) were enrolled. All children underwent a laryngoscopy and a 24-hour dual-probe pH monitoring. At both sensor, distal and proximal esophageal, a pathological GER was defined as the presence of episodes of acid reflux with pH < 4 during a fraction of the total recording time greater than 5.2 percent. The computer considered the child was supine when asleep and upright when awake. Laryngoscopy revealed interarytenoid erythema and/or edema with vocal cord nodules or granulomas in 13 cases (76.4%), isolated vocal nodules or granulomas in three cases (17.6%) and a normal appearance in one case (5.8%). At both sensors, the majority of refluxes occurred when the child was upright, as analyzed by the percentage of time the intra-esophageal pH was below four (% time pH < 4), number of refluxes, reflux episodes/hour and longest reflux episode, p < 0.05 between upright and supine for each parameter. The median total % time pH < 4 on the proximal and distal probes was respectively 1.62 percent (95% CI 1.50-3.79) and 11.49 percent (95% CI 8.81-27.17), p < 0.0003. Among the 17 hoarse children, a pathological GER was observed in 12 (70.5%) at the distal sensor and in three (17.5%) at both sensors. Among the 16 hoarse children with abnormal findings on laryngoscopy, two (12.5%) had diagnosed pathological GER at the proximal and 11 (68.7%) at the distal sensor. The only child with normal findings on laryngoscopy exhibited a pathological GER at both sensors. Our results suggest that chronic hoarseness is associated with a pathological GER. The majority of these documented refluxes occurred when the child was awake.

Gastropharyngeal and gastroesophageal reflux in globus and hoarseness

BACKGROUND

The role of gastropharyngeal reflux in patients with globus pharyngeus and hoarseness remains unclear.

OBJECTIVE

To evaluate patients with complaints of globus, hoarseness, or globus and hoarseness combined for the presence of gastropharyngeal and gastroesophageal reflux.

DESIGN

Prospective clinical cohort study of 3 groups of patients undergoing ambulatory 24-hour double-probe pH monitoring. In patients with pathologic gastroesophageal reflux, an upper gastrointestinal endoscopy was also performed.

SETTING

Tertiary care, outpatient clinic.

PATIENTS

Twenty-seven patients with globus alone, 20 patients with hoarseness alone, and 25 patients with globus and hoarseness combined.

RESULTS

Patients with well-defined pathologic reflux (ie, gastroesophageal reflux with or without gastropharyngeal reflux) were present mainly in the group of patients with globus combined with hoarseness: 18 (72%) of 25 patients, compared with 7 (35%) of 20 patients with hoarseness alone and 8 (30%) of 27 with globus alone. Seven (10%) of all 72 patients had prolonged acid exposure at the laryngopharyngeal junction in the presence of a normal gastroesophageal pH registration. Abnormal findings in the esophagus were found at endoscopy in 17 (65%) of 26 patients with pathologic gastroesophageal reflux (with or without gastropharyngeal reflux).

CONCLUSIONS

We found a high prevalence of pathologic reflux in patients with both globus and hoarseness. Based on these findings, we strongly advise upper gastrointestinal endoscopy for symptomatic otolaryngological patients with pathologic gastroesophageal reflux.

Acoustic voice analysis by means of the hoarseness diagram

The hoarseness diagram (Michaelis, Fröhlich, & Strube, 1998a) has been proposed as a new approach to describe different acoustic properties of voices. To test its performance in the analysis of pathologically disturbed and normal voices five requirements are suggested that should be met by any acoustic voice-analysis protocol to be used in voice research and clinical practice. The hoarseness diagram is then tested with regard to these requirements. Individual voices are found to show a satisfactory localization in the diagram. Aspects of stationarity are discussed in the context of four case studies. The different cases illustrate that changes in the acoustic analysis results are observed if the voice-generation conditions change, whereas results are stationary if phonation conditions do not change. Different pathological voice groups defined on grounds of the specific phonation mechanism are found to map to specific regions of the hoarseness diagram, with differences between group locations being significant. All results can be interpreted without exceptions if the two hoarseness diagram coordinates are taken to reflect the vibrational irregularity of the voice-generation mechanisms on the one side and the degree of closure of the vibrating structures on the other side. The hoarseness diagram and its underlying algorithms are thus shown to constitute a useful approach to acoustic voice analysis in research and clinical practice. The tests themselves demonstrate several application possibilities, including the quantitative monitoring of individual voices.

Phonomicrosurgical management of vocal fold polyps: the subepithelial microflap resection technique

Vocal fold polyps are typically caused by acute and chronic trauma to the microvasculature of the superficial lamina propria (SLP). Shearing stresses that are induced by hyperfunctional glottal sound production lead to bleeding into the SLP and malformed neo-vascularized masses. Because the primary process does not involve the epithelium, the authors designed a technique to resect hemorrhagic polyps by epithelial cordotomy with partial or complete preservation of the vocal fold epithelium. This approach is different from the traditional microsurgical resection of hemorrhagic polyps by amputation with or without the carbon dioxide laser. Forty patients who underwent microlaryngoscopic resection of hemorrhagic polyps from 1996 through 1998 were reviewed retrospectively. Thirty-six of the 40 procedures were by epithelial cordotomy and subepithelial removal of the polyp contents. Sixteen of 36 were assisted by a subepithelial infusion of saline and epinephrine, and all were 3 mm to 6 mm. Four of 40 polyps were amputated; all of these were less than 3 mm and were pedicled on a narrow base. Cold instruments were used exclusively in all 40 patients. Postoperative laryngeal stroboscopy within 2 weeks revealed improved mucosal wave propagation and improved glottal closure in all 33 patients in whom postoperative strobovideolaryngoscopy was available. The epithelial cordotomy technique was introduced to minimize disturbance of normal SLP and epithelium. Despite the hemorrhagic nature of these lesions, cold instruments could be used exclusively with facility due to careful microdissection between the polyp and the residual normal SLP and the enhanced hemostasis provided by the subepithelial infusion of saline and epinephrine. The rapid return to improved glottal function is the result of this ultra tissue-sparing technique.

Vocal mechanics as the basis for phonosurgery

OBJECTIVE

A number of modifications in laryngoplastic phonosurgery have recently been proposed. This report is intended to clarify the concept on which the surgery should be based, vocal mechanics, for further rational development of the surgery.

STUDY DESIGN

The results of various previous surgeries were compared. In an attempt to elucidate what makes the difference in the results, simulation of voice production was conducted with the use of excised larynges.

METHODS

Excised larynges were mounted on a tube so as to be blown from below. Experimental variables in the model included the glottal area initially set, stiffness of the vocal folds, and subglottal pressure. The conditions under which the voice became hoarse were examined.

RESULTS

The voice became hoarse under the following major conditions: 1) the initial glottal area exceeded a certain value, 2) stiffness was too high, and 3) the glottis was too tightly closed. Clinical representation for each condition was made, particularly for excessively tight glottal closure such as in spasmodic dysphonia. A new type of surgical treatment for spasmodic dysphonia, lateralization thyroplasty, was briefly reported, which restored the voice to normal without recurrence for 1 year at the time of this writing.

CONCLUSIONS

A potential new type of laryngoplastic phonosurgery should be conformed to the mechanics of voice production. In treating dysphonia, it is often necessary to switch from etiologic or radical treatment, if infertile, to symptomatic treatment instead, at the level of mechanics.

Retrosternal goiter: a six-year institutional review

Retrosternal goiter is defined as any goiter in which at least 50 per cent of the thyroid resides below the level of the thoracic inlet. The incidence of retrosternal goiter varies from 3 to 20 per cent with respect to thyroidectomy patients. A retrospective chart review from June 1991 to December 1997 found 232 thyroidectomies performed at our institution. Sixteen patients were found to have retrosternal goiters (6.9%). The mean age was 57.8 years (range, 34-92). All were of benign pathology. Symptoms included shortness of breath (68.8%), hoarseness (37.5%), dysphagia (31.3%), and superior vena cava obstruction (6.25%). Thirteen patients were female (81.3%). Fifteen patients had surgical intervention (93.8%). Total thyroidectomy was performed in nine cases (60%), whereas lobectomy was performed in six cases (40%). All treated patients had complete resolution of symptoms. A cervical incision alone was used in 13 cases (86.7%). Complications consisted of one postoperative pleural effusion and in one case a traumatic C5 nerve root compression occurred. There were no instances of long-term vocal cord paralysis or hypoparathyroidism. There was no perioperative mortality. In the majority of patients with retrosternal goiter, surgery can be done expeditiously through a cervical incision with minimal morbidity and mortality.

[Hoarseness resulting from post-intubation arytenoid cartilage subluxation in an 11-year-old girl]

There has been described a case of the right arytenoid cartilage subluxation in a 11-year-old girl who underwent several intubations and bronchoscopies as a newborn and an infant. The voice has gone hoarse owing to those interventions. Videolaryngoscopy revealed anterior and medial dislocation of the right arytenoid cartilage accompanied by the immobility in the cricoarytenoid joint, right vocal movement being preserved. Voice therapy was not successful as the parents lost their interest, considering the present child's voice to be normal.

[The application of frequency-domain harmonics-to-noise ratio in the acoustic analysis of the normal voice and the abnormal voice]

The frequency-domain relative harmonics-to-noise ratios were analysed in 36 normal women and 30 patients who had suffered from abnormal voice. The result indicated: the frequency-domain relative harmonics-to-noise ratios of the normal voice were distributed stably and the relative harmonics-to-noise ratios of the diseased voice differed obviously from that of the normal one above 1,700 Hz (P < 0.01). The frequency-domain relative harmonics-to-noise ratio was considered as a valuable parameter in distinguishing normal voice and diseased voice.

[Functional voice quality assessment in curative microsurgery of laryngeal malignancies. Postoperative voice rehabilitation based on the "laryngeal double valve function"]

According to Negus and Pressman the sphincter systems of the vocal folds and the ventricular folds form a respiratory "laryngeal double valve function". Correspondingly, we found a physiological phonation system of the glottis and a pathological-compensatory one of the supraglottis. They appear to be regulated through an automatic phonatory control system with the glottal phonatory function evidently acting as sensor level. In order to confirm this hypothesis, objective voice analyses with glottal-relevant parameters of 26 voice-rehabilitated patients after minimally invasive laser surgery of glottal carcinomas are presented and integrated into a "hoarseness diagram" with the coordinates roughness and breathiness. Using statistically deliminated acoustic dusters, our data show a qualitative hierarchy of different postoperative phonation mechanisms. They demonstrate the influence of the vibratory capacity of glottal and supraglottal structures on the quality of the vibratory closure. Both functional parameters evidently determine the resulting voice quality in the sense of our hypothesis.

[An overview of the symptoms and signs of voice disorders and the pathophysiology of hoarseness]

Voice disorders are due to organic and functional disturbances of the voice generator, activator and resonator. They appear as a consequence of different factors which lead to the development of hoarseness, and may as well be the result of disturbed phonatory patterns. Phonatory patterns refer primarily to the muscular activity of the vocal system, which is delicately balanced within the voice generator, activator and resonator. PATHOPHYSIOLOGY OF HOARSENESS: Basic causes of hoarseness are insufficient glottic closure during phonation (glottal gap), changes in the vocal fold stiffness and imbalance in mechanical properties between the two folds. Glottal gap leads to the excessive air leakage during phonalion and insufficient conversion of the expiratory air into pulses. Turbulence of the expiratory air particles is increased, leading to the development of noise. Excessively stiff or tax vocal folds, both disturb the vibration process and lead to the development of noise and hoarseness. Imbalance in tension between the two folds, and especially in their mass, may lead to the glottal gap, with the consecutive noise and hoarseness. PHONATORY PATTERNS: Phonatory patterns refer to habitual movements of the vocal organs during phonation and speech, which are acquired during the process of learning phonation and speech. This is primarily the muscular activity of generator, activator and resonator of the voice, which is so balanced to produce the optimal voice quality with the least effort and fatigue. The activity of the phonatory organs is not well balanced in cases of voice disorders. That is the primary cause of functional voice disorders, and a very frequent consequence of organic voice disturbances. Hyperkinetic dysphonia is the most common type of disturbed phonatory patterns, characterized by excessive vocal effort, while hypokinetic dysphonia is rarely seen. The third type of functional disorders of the phonatory patterns is an incorrect placement of the voice (imposlatio falsa), which is characterized by an imbalanced muscular activity of the vocal organs, but within the normal limits concerning the overall amount of activity.