Analysis of spasmodic dysphonia by aerodynamic and laryngostroboscopic measurements

Sequential assessment of laryngeal function using laryngostroboscopy and phonatory air flow assessment was carried out in 18 patients with spasmodic dysphonia (SD). Comparison was made between findings in patients before treatment (n = 18), after unilateral recurrent nerve block by lidocaine (n = 6), after bilateral injections of botulinum toxin (Botox) (n = 13), and prior to Botox reinjection (n = 3). Unilateral nerve block resulted in higher mean phonatory airflows than after bilateral Botox injections. Both unilateral nerve block and Botox injections increased fluctuant or alternating flow source (AC); however, unilateral nerve block resulted in more unmodulated airflow leakage. Phonation time on a single breath was longer than with Botox injection. Bilateral Botox injections resulted in better glottal closure, fewer instances of vocal fold level differences, and, better vocal fold vibrations with phase symmetry, as determined by laryngostroboscopy. Partial bilateral denervation using Botox resulted in laryngeal function, which appeared to be intermediate between that of tightly squeezed pretreatment status and a breathy voice with incomplete adduction after unilateral nerve block. Of all treatments assessed, bilateral partial denervation by Botox appeared to be the most physiologic in restoring normal vocal fold vibratory function and airflow.     

Botulinum toxin injection in the treatment of vocal fold paralysis associated with multiple sclerosis: A case report

Botulinum toxin has been demonstrated clinically to be an effective treatment for a variety of laryngeal problems, most notably spasmodic dysphonia. As in other movement disorders, the theory behind the injection of this substance in the larynx has been a weakening of the vocal fold musculature to relieve uncoordinated and spasmodic movement of the vocal folds, presumably rebalancing the forces within the intralaryngeal musculature. Recently, this concept was applied to help reposition the arytenoid cartilage in acute and longstanding anteromedial cricoarytenoid dislocations. This same concept may apply to the paralyzed vocal fold. In support of this idea, a number of investigators have shown that immobile, clinically paralyzed vocal folds may still have partial voluntary motor unit activity. This voluntary activation may not produce clinically evident movement but may be sufficient to produce tone within the fold. If the voluntary motor units in the abductor musculature of the paralyzed fold are weakened with botulinum toxin, the continued pull of the functioning adductor musculature may be sufficient to medialize the paralyzed fold. This idea has been supported by animal experiments, which have shown that botulinum toxin may affect the ability of the fold to rebalance itself. With this evidence in mind, a patient with fold immobility secondary to multiple sclerosis was treated in an attempt at laryngeal rebalancing, using botulinum toxin to medialize the fold. However, instead of simply having the fold return fixed to the midline, the patient regained normal laryngeal mobility and voice. While it is unclear whether the botulinum toxin alone was responsible, the coincidence of this occurrence certainly requires reporting. This paper is a report of the first successful treatment of vocal fold paralysis using botulinum toxin to treat vocal fold fixation in a patient with multiple sclerosis.     

Combined-modality treatment of adductor spasmodic dysphonia with botulinum toxin and voice therapy

A combined-modality treatment program consisting of botulinum toxin injection (Botox) and voice therapy was used to treat 17 subjects diagnosed with adductor spasmodic dysphonia (ADD SD). Ten subjects with ADD SD served as the control and were given Botox only. Voice therapy after Botox injection was directed toward reducing the hyperfunctional vocal behaviors, primarily glottal overpressure at voice onset and anterior-posterior squeezing. The results indicated that subjects who underwent combined-modality treatment maintained significantly higher mean airflow rates for significantly longer periods. Moreover, there was a carryover effect in these patients when they received Botox only. Adductor spasmodic dysphonia is treated most effectively when intrinsic laryngeal muscle spasms are reduced or eliminated by Botox injection and extrinsic hyperfunctional vocal behaviors are treated with voice therapy     

Botox for hyperadduction of the false vocal folds: A case report

We present a patient with severe hyperadduction of the false vocal folds (FVF) treated with Botulinum Toxin injections to each FVF. This patient presented with severe dysphonia and was found to demonstrate severe hyperadduction of the FVF's with all phonatory tasks. The patient was treated with extensive speech therapy without improvement in voice quality nor FVF motion pattern. He was then injected with Botox A bilaterally using a peroral approach to the FVFs. Shortly after treatment the patient experienced dramatic improvement in voice quality. Videolaryngoscopy revealed no adduction of the FVFs with phonation and essentially normal true vocal fold motion. He remained with normal voice quality one year after treatment without any further treatment. Possible mechanism of action of this type of treatment are discussed.     

The effect of patient factors on response outcomes toBotox treatment of spasmodic dysphonia

Injection of botulinum toxin (Botox) into the laryngeal muscleshas become the treatment of choice for controlling the symptoms of spasmodic dysphonia (SD). Currently, no specific battery of objective tests to assess the outcome is universally accepted. The purpose of this study was to investigate demographic, clinical, and treatment factors with voice outcome following Botox injection. Sixty-eight patients with adductor SD who underwent at least one Botox injection during a 5-year period were studied. Voice outcome measures were made from patient self-reporting scales and included overall vocal quality, length of response, and duration of breathiness. Vocal quality was significantly correlated with the underlying severity of vocal symptoms prior to treatment, incidence of breathiness and unilateral versus bilateral injection. The length of response was greater in males and following bilateral injections. An increased period of breathiness significantly correlated with bilateral injections.     

Relationship among glottal area, static supraglottic compression, and laryngeal function studies in unilateral vocal fold paresis and paralysis

In this study, we evaluated the relationship between laryngeal function measures and glottal gap ratio and normalized measures of supraglottic behaviors in patients with unilateral vocal fold paresis (UVFP). Thirty-one patients were found to have unilateral vocal fold paresis by videoendoscopy and laryngeal electromyography, and 13 controls participated in this study. Patients with UVFP demonstrated significantly larger glottal gap ratios (p = 0.016) than control subjects. The nonparalyzed or contralateral vocal fold was associated with significantly more static false vocal fold compression (p = 0.03) compared with the paralyzed vocal fold or with the controls. Patients with unilateral vocal fold paresis were divided into subgroups: those with normal or abnormal maximum phonation time, flow, or pressure measures. Smaller glottal gap ratios were identified in patients with normal maximum phonation times and flow measures. Greater false vocal fold activity was identified in unilateral vocal fold paresis patients with normal laryngeal function measures than in unilateral vocal fold paresis patients with abnormal measures. These findings suggest that some patients with documented unilateral paresis and glottal incompetence can compensate for vocal fold weakness such that their acoustic and aerodynamic measures are normal.     

Preliminary Results of a New Temporary Vocal Fold Injection Material

Temporary vocal fold injection is a valuable procedure for vocal fold paralysis or paresis of uncertain permanency and as a trial augmentation to decide the value of vocal fold augmentation. A new material made from glycerin, carboxymethylcellulose, and water has recently been developed for temporary vocal fold augmentation. Eleven patients underwent vocal fold injection for the treatment of glottal incompetence with this material. The duration of effectiveness of this injection material was 2 to 3 months depending on the injection amount. This new material satisfies several requirements for an ideal temporary vocal fold injection material in terms of injectability, convenience, duration of effectiveness, and safety. The authors conclude that this new material is a good option for temporary vocal fold augmentation.     

Spatial arrangement of the structural elements ofvocal fold layers: An adjustment to the vibration process

It is well established that the multilayered structure of the vocal fold is highly adjusted to the requirements of the vibration process during phonation. There is also some partial data indicating that the spatial arrangement of each vocal fold layer corresponds to the functional requirements, and thus facilitate the phonation process. Nevertheless, all reports on the spatial arrangement of the vocal fold structures deal only with an individual element of the vocal fold histologic structure. The present study encompasses the spatial histologic analysis of all major elements of the vocal fold layers. It was demonstrated that the vocal fold epithelial cells, the connective and muscle fibers, and even the blood vessels run parallel to the vocal fold free edge, which indicates a high adjustment to the phonation requirements and the vibration process.     

Interstitial protein alterations in rabbit vocal fold with scar

Fibrous and interstitial proteins compose the extracellular matrix of the vocal fold lamina propria and account for its biomechanic properties. Vocal fold scarring is characterized by altered biomechanical properties, which create dysphonia. Although alterations of the fibrous proteins have been confirmed in the rabbit vocal fold scar, interstitial proteins, which are known to be important in wound repair, have not been investigated to date. Using a rabbit model, interstitial proteins decorin, fibromodulin, and fibronectin were examined immunohistologically, two months postinduction of vocal fold scar by means of forcep biopsy. Significantly decreased decorin and fibromodulin with significantly increased fibronectin characterized scarred vocal fold tissue. The implications of altered interstitial proteins levels and their affect on the fibrous proteins will be discussed in relation to increased vocal fold stiffness and viscosity, which characterizes vocal fold scar.     

Chaotic vibrations of a vocal fold model with a unilateral polyp

A nonlinear model was proposed to study chaotic vibrations of vocal folds with a unilateral vocal polyp. The model study found that the vocal polyp affected glottal closure and caused aperiodic vocal fold vibrations. Using nonlinear dynamic methods, aperiodic vibrations of the vocal fold model with a polyp were attributed to low-dimensional chaos. Bifurcation diagrams showed that vocal polyp size, stiffness, and damping had important effects on vocal fold vibrations. An increase in polyp size tended to induce subharmonic patterns and chaos. This study provides a theoretical basis to model aperiodic vibrations of vocal folds with a laryngeal mass.     

A model for vocal fold vibratory motion, contact area, and the electroglottogram

The electroglottogram (EGG) has been conjectured to be related to the area of contact between the vocal folds. This hypothesis has been substantiated only partially via direct and indirect observations. In this paper, a simple model of vocal fold vibratory motion is used to estimate the vocal fold contact area as a function of time. This model employs a limited number of vocal fold vibratory features extracted from ultra high-speed laryngeal films. These characteristics include the opening and closing vocal fold angles and the lag (phase difference) between the upper and lower vocal fold margins. The electroglottogram is simulated using the contact area, and the EGG waveforms are compared to measured EGGs for normal male voices producing both modal and pulse register tones. The model also predicts EGG waveforms for vocal fold vibration associated with a nodule or polyp.     

Infraglottic aspect of canine vocal fold vibration: Effect of increase of mean airflow rate and lengthening of vocal fold

The mucosal upheaval (MU), where the mucosal wave starts and propagates upward, appears only when the vocal fold vibrates. The location of the MU histologically and the effect of changes in mean air flow rate (MFR) and vocal fold length on occurrence of the MU were studied in twelve excised canine larynges. The lower surface of the vocal fold was marked to serve as a landmark for subsequent study. Cricothyroid approximation was performed to lengthen the vocal fold. After taking high-speed pictures or recording stroboscopic images from the tracheal side, a small cut wound was made at the mark. This wound served to compare the position of the MU with the histologically identified location of the mark. The larynx was then sectioned in the frontal plane. Before lengthening the vocal fold, the MU occurred on the area where the lamina propria became thinner and where the muscular layer neared the epithelial layer. After lengthening the vocal fold, the MU actually shifted medially compared with its original position. The subglottic area surrounded by the bilateral MUs became longer and thinner. Whether or not complete glottal closure during a vibratory cycle was achieved did not alter these findings. In contrast, with a fixed vocal fold length the MU appeared more laterally as MFR increased, but, based on the relation with the mark, its location on the vocal fold did not change from its original position before increase of MFR.     

Vocal fold augmentation with injectable calcium hydroxylapatite: short-term results.

Symptoms of unilateral vocal fold paralysis are improved significantly by augmenting the paralyzed vocal fold via vocal fold injection. In this trial, augmentation with a new calcium hydroxylapatite implant was evaluated. In addition, two different phonosurgical injection techniques were used, and these procedures were compared for accuracy and reliability. A total of 11 terminal patients with unilateral vocal fold paralysis underwent vocal fold injection with calcium hydroxylapatite. Efficacy of the implant was evaluated by comparing results from the Voice Handicap Index (VHI) and mean airflow measurements before and 6 months after injection. Surgeon evaluations determined the comparative benefits of either endoscopic direct vocal fold injection or percutaneous vocal fold injection. Six-month data were obtained for a cohort of five patients. VHI scores improved for all five patients available for full evaluation and four of the five achieved improvements in mean airflow rates. Of the remaining patients, one later had a medialization laryngoplasty, two died from their terminal diseases before the 6-month follow-up, and two of the remaining three reported satisfaction with the results via telephone follow-up. Vocal fold injection via endoscopic, direct laryngoscopy was found to be a more reliable procedure for vocal fold injection than percutaneous injection. Slight overinjection (10% to 15%) was found to provide optimum results. Vocal fold injection of calcium hydroxylapatite for unilateral vocal fold paralysis improved voice quality and reduced mean airflow rates in this patient group with short-term results. Long-term studies are needed to confirm the durability of these findings.     

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.     

Strobophotoglottographic transillumination as a method for the analysis of vocal fold vibration patterns

The purpose of this exploratory study was to determine if laryngeal transillumination in combination with stroboscopy (strobophotoglottography; SPGG) is useful for (1) the visualization of vocal fold vibration (VFV) opening patterns, (2) the localization of initial vocal fold opening in horizontal glottal thirds (anterior, midmembranous, and posterior), (3) determination of the temporal correspondence of the so-called electroglottography (EGG)-knee and initial vocal fold separation, and, finally, (4) automatized quantitative measurements of glottal area function within endoscopic images. With stroboscopic transillumination, initial inferior vocal fold separation was detectable during the "closed" phase, where the vocal folds were still closed in the upper portion and therefore initial inferior vocal fold separation could not be visualized with usual laryngoscopy techniques. In the horizontal plane within similar fundamental frequencies in modal voice registers in two male subjects, localization of initial glottal opening depended on the voice types used (soft, normal, or pressed phonation). We found zipperlike posterior-to-anterior openings, initial midmembranous openings, initial anterior openings, as well as simultaneous initial opening of all three portions in the two healthy male adults examined. This technique proved to add temporal and spatial information to vocal fold opening patterns and extends our examination techniques to the very beginning of vocal fold opening at the inferior portion. Simultaneous electroglottogram tracking and comparison with bidirectionally illuminated stroboscopic images revealed a time-locked correspondence of the EGG-knee with the aforementioned initial inferior vocal fold separation. Bidirectional illumination combined with digital color extraction techniques allowed for image separation of subglottally and supraglottally illuminated structures. This facilitated vocal fold contour detection and automatized image processing, for example, for determination of glottal area function, and is considered to be a further step to objective automatized quantitative measurements within endoscopic images.     

Autologous fat implantation for vocal fold scar: A preliminary report

New insights into the anatomy and physiology of phonation, along with technological advances in voice assessment and quantification, have led to dramatic improvements in medical voice care. Techniques to prevent vocal fold scar have been among the most important, especially scarring and hoarseness associated with voice surgery. Nevertheless, dysphonia due to vocal fold scar is still encountered all too frequently. Although it is not generally possible to restore such injured voices to normal, patients with scar-induced dysphonia can usually be helped. Voice improvement is optimized through a team approach. Treatment may include sophisticated voice therapy and vocal fold surgery. Although experience with collagen injection has been encouraging in selected cases (particularly in those involving limited areas of vocal fold scar), there is no consistently successful surgical technique. Attempts to treat massive vocal fold scar, such as may be seen following vocal fold stripping, have been particularly unsuccessful. This paper reports preliminary experience with the implantation of autologous fat into the vibratory margin of the vocal fold of patients with severe, extensive scarring. Using this technique, it appears possible to recreate a mucosal wave and improve voice quality. Additional research is needed.     

Glottal opening in patients with vocal fold tissue changes

Synchronized videostroboscopy and electroglottography were applied to the measurement of anterior-to-posterior open glottal length in four groups of patients; two with no clinically significant voice disorder, one with vocal fold polyps, and one with vocal fold nodules. The data showed that the groups did not differ significantly when open glottal length was measured at the time of minimum glottal opening. The pathological groups had significantly lower open glottal length measurements, however, when measurements were obtained at the time that vocal fold contact was initiated during the glottal cycle. The findings are preliminary evidence that vocal fold neoplasms may not have the effect of reducing glottal closure, as previously suggested in the literature. The data also highlight the importance of examining differential effects of vocal fold neoplasms at various points throughout the glottal cycle.     

Model-based classification of nonstationary vocal fold vibrations

Classification of vocal fold vibrations is an essential task of the objective assessment of voice disorders. For historical reasons, the conventional clinical examination of vocal fold vibrations is done during stationary, sustained phonation. However, the conclusions drawn from a stationary phonation are restricted to the observed steady-state vocal fold vibrations and cannot be generalized to voice mechanisms during running speech. This study addresses the approach of classifying real-time recordings of vocal fold oscillations during a nonstationary phonation paradigm in the form of a pitch raise. The classification is based on asymmetry measures derived from a time-dependent biomechanical two-mass model of the vocal folds which is adapted to observed vocal fold motion curves with an optimization procedure. After verification of the algorithm performance the method was applied to clinical problems. Recordings of ten subjects with normal voice and ten dysphonic subjects have been evaluated during stationary as well as nonstationary phonation. In the case of nonstationary phonation the model-based classification into "normal" and "dysphonic" succeeds in all cases, while it fails in the case of sustained phonation. The nonstationary vocal fold vibrations contain additional information about vocal fold irregularities, which are needed for an objective interpretation and classification of voice disorders.     

Spatiotemporal classification of vocal fold dynamics by a multimass model comprising time-dependent parameters

A model-based approach is proposed to objectively measure and classify vocal fold vibrations by left-right asymmetries along the anterior-posterior direction, especially in the case of nonstationary phonation. For this purpose, vocal fold dynamics are recorded in real time with a digital high-speed camera during phonation of sustained vowels as well as pitch raises. The dynamics of a multimass model with time-dependent parameters are matched to vocal fold vibrations extracted at dorsal, medial, and ventral positions by an automatic optimization procedure. The block-based optimization accounts for nonstationary vibrations and compares the vocal fold and model dynamics by wavelet coefficients. The optimization is verified with synthetically generated data sets and is applied to 40 clinical high-speed recordings comprising normal and pathological voice subjects. The resulting model parameters allow an intuitive visual assessment of vocal fold instabilities within an asymmetry diagram and are applicable to an objective quantification of asymmetries.