Laryngeal electromyography: an evidence-based review

Botulinum Neurotoxin Therapy in the Clinical Management of Laryngeal Dystonia

Laryngeal dystonia (LD), or spasmodic dysphonia (SD), is a chronic, task-specific, focal movement disorder affecting the larynx. It interferes primarily with the essential functions of phonation and speech. LD affects patients' ability to communicate effectively and significantly diminishes their quality of life. Botulinum neurotoxin was first used as a therapeutic agent in the treatment of LD four decades ago and remains the standard of care for the treatment of LD. This article provides an overview of the clinical application of botulinum neurotoxin in the management of LD, focusing on the classification for this disorder, its pathophysiology, clinical assessment and diagnosis, the role of laryngeal electromyography and a summary of therapeutic injection techniques, including a comprehensive description of various procedural approaches, recommendations for injection sites and dosage considerations.

LaDIVA: A neurocomputational model providing laryngeal motor control for speech acquisition and production

Many voice disorders are the result of intricate neural and/or biomechanical impairments that are poorly understood. The limited knowledge of their etiological and pathophysiological mechanisms hampers effective clinical management. Behavioral studies have been used concurrently with computational models to better understand typical and pathological laryngeal motor control. Thus far, however, a unified computational framework that quantitatively integrates physiologically relevant models of phonation with the neural control of speech has not been developed. Here, we introduce LaDIVA, a novel neurocomputational model with physiologically based laryngeal motor control. We combined the DIVA model (an established neural network model of speech motor control) with the extended body-cover model (a physics-based vocal fold model). The resulting integrated model, LaDIVA, was validated by comparing its model simulations with behavioral responses to perturbations of auditory vocal fundamental frequency (fo) feedback in adults with typical speech. LaDIVA demonstrated capability to simulate different modes of laryngeal motor control, ranging from short-term (i.e., reflexive) and long-term (i.e., adaptive) auditory feedback paradigms, to generating prosodic contours in speech. Simulations showed that LaDIVA’s laryngeal motor control displays properties of motor equivalence, i.e., LaDIVA could robustly generate compensatory responses to reflexive vocal fo perturbations with varying initial laryngeal muscle activation levels leading to the same output. The model can also generate prosodic contours for studying laryngeal motor control in running speech. LaDIVA can expand the understanding of the physiology of human phonation to enable, for the first time, the investigation of causal effects of neural motor control in the fine structure of the vocal signal.

The Hellenic Voice Handicap Index of Different Laryngeal Mass Lesions: A Receiver-Operating Characteristic Analysis

BACKGROUND

Voice disorders influence the quality of people's life. When the type of disorder is determined then the clinicians are capable of finding their patients' needs and address their complaints concerning their vocal problems. One of the most used tools, for assessing the patients' quality of life (in accordance with their vocal status), is the Voice Handicap Index. In this study, we determined the cut-off scores of Voice Handicap Index for population with laryngeal mass lesions such as vocal polyps and nodules. The calculated cut-off points further guide clinicians toward applying a needed interventional method/therapy even in the cases where the condition of a person could not be easily estimated.

METHODS

The study involved 130 participants (aged 19-74). Specifically, 90 nondysphonic people served as the control group, while 40 participants had already been diagnosed with voice disorders due to laryngeal mass lesions. Participants who were diagnosed with a laryngeal inflammation or had undergone a surgery were excluded from the study. The cut-off scores were determined through a receiver-operating characteristic (ROC) analysis.

RESULTS

The calculated cut-off points were 19.50 for the total score of VHI, 7.50 for the functional domain, and 8.50 for the physical and the emotional domain.

CONCLUSIONS

The aforementioned cut-off points could be used in empowering the everyday clinical practice. Moreover, their knowledge could help the construction of an individualized therapy plan, as well as monitoring-biofeedback tool for the populations with vocal fold lesions.

Predicting the Outcome of Unilateral Vocal Fold Paralysis: A Multivariate Discriminating Model Including Grade of Dysphonia, Jitter, Shimmer, and Voice Handicap Index-10

OBJECTIVES

The aim of this study was to investigate if any clinical and phoniatric characteristics or quality-of-life measures could predict the outcome of unilateral vocal fold paralysis (UVFP) initially managed with speech therapy.

METHODS

Forty-six patients with UVFP were evaluated using laryngostroboscopy, the GIRBAS (grade, instability, roughness, breathiness, asthenia, and strain) scale, acoustic analysis, and the Voice Handicap Index-10 (VHI-10) questionnaire. Treatment was speech therapy according to a 3-phase protocol. The main outcome measure was incomplete vocal fold mobility 12 months after symptom onset. Univariate and multivariate modeling ( k-nearest neighbors model) were applied.

RESULTS

Fifteen patients had incomplete motion recovery 12 months after the onset of UVFP. On univariate analysis, time to diagnosis (0.01), global grade of dysphonia (0.018), jitter (0.01), shimmer (0.012), and VHI-10 score (0.006) were associated with the outcome of vocal fold paralysis. Using a k-nearest neighbors multivariate discriminating model, the best discrimination of UVFP outcome was achieved with 4 parameters: global grade of dysphonia 2 or 3, jitter > 2.46%, shimmer > 6.97%, and VHI-10 score > 13. The model's misclassification rate for incomplete motion recovery was only 6%. The model showed sensitivity of 93% and specificity of 74%.

CONCLUSIONS

Delayed diagnosis and speech therapy was associated with negative outcomes. Higher grade of dysphonia, jitter, shimmer, and VHI-10 score on initial phoniatric assessment may help clinicians in predicting the outcomes of UVFP patients.

Acoustic and Perceived Measurements Certifying Tango as Voice Treatment Method

Voice disorders are affecting everyday life in many levels, and their prevalence has been studied extensively in certain and general populations. Notably, several factors have a cohesive influence on voice disorders and voice characteristics. Several studies report that health and environmental and psychological etiologies can serve as risk factors for voice disorders. Many diagnostic protocols, in the literature, evaluate voice and its parameters leading to direct or indirect treatment intervention. This study was designed to examine the effect of tango on adult acoustic voice parameters. Fifty-two adults (26 male and 26 female) were recruited and divided into four subgroups (male dancers, female dancers, male nondancers, and female nondancers). The participants were asked to answer two questionnaires (Voice Handicap Index and Voice Evaluation Form), and their voices were recorded before and after the tango dance session. Moreover, water consumption was investigated. The study's results indicated that the voices' acoustic characteristics were different between tango dancers and the control group. The beneficial results are far from prominent as they prove that tango dance can serve stand-alone as voice therapy without the need for hydration. Also, more research is imperative to be conducted on a longitudinal basis to obtain a more accurate result on the required time for the proposed therapy.

Using Receiver Operating Characteristic Curve to Define the Cutoff Points of Voice Handicap Index Applied to Young Adult Male Smokers

Voice performance is an inextricable key factor of everyday life. Obviously, the deterioration of voice quality can cause various problems to human communication and can therefore reduce the performance of social skills (relevant to voice). The deterioration could be originated from changes inside the system of the vocal tract and larynx. Various prognostic methods exist, and among them is the Voice Handicap Index (VHI). This tool includes self-reported questionnaires, used for determining the cutoff points of total score and of its three domains relevant to young male Greek smokers. The interpretation of the calculated cutoff points can serve as a strong indicator of imminent or future evaluation by a clinician. Consistent with previous calculation, the VHI can also act as a feedback for smokers' voice condition and as monitoring procedure toward smoking cessation. Specifically, the sample consisted of 130 male nondysphonic smokers (aged 18-33 years) who all participated in the VHI test procedure. The test results (through receiver operating characteristic analysis) concluded to a total cutoff point score of 19.50 (sensitivity: 0.838, 1-specificity: 0). Also, in terms of constructs, the Functional domain was equal to 7.50 (sensitivity: 0.676, 1-specificity: 0.032), the Physical domain was equal to 7.50 (sensitivity: 0.706, 1-specificity: 0.032), and the Emotional domain was equal to 6.50 (sensitivity: 0.809, 1-specificity: 0.048).

Voice Handicap Index and Interpretation of the Cutoff Points Using Receiver Operating Characteristic Curve as Screening for Young Adult Female Smokers

The relationship between smoking and alterations of the vocal tract and larynx is well known. This pathology leads to the degradation of voice performance in daily living. Multiple assessment methods of vocal tract and larynx have been developed, and in recent years they were enriched with self-reported questionnaires such as Voice Handicap Index (VHI). This study determined the cutoff points of VHI's total score and its three domains for young female smokers in Greece. These estimated cutoff points could be used by voice specialists as an indicator for further clinical evaluation (foreseeing a potential risk of developing a vocal symptom because of smoking habits). A sample of 120 female nondysphonic smokers (aged 18-31) was recruited. Participants filled out the VHI and Voice Evaluation Form. VHI's cutoff point of total score was calculated at the value of 19.50 (sensitivity: 0.780, 1-specificity: 0.133). Specifically, the construct domain of functional was 7.50 (sensitivity: 0.900, 1-specificity: 0.217), for physical it was 8.50 (sensitivity: 0.867, 1-specificity: 0.483), and for emotional it was 7.50 (sensitivity: 0.833, 1-specificity: 0.200) through the use of receiver operating characteristic. Furthermore, VHI could be used as a monitoring tool for smokers and as a feedback for smoking cessation.

Laryngeal Reflexes: Physiology, Technique, and Clinical Use

This review examines the current level of knowledge and techniques available for the study of laryngeal reflexes. Overall, the larynx is under constant control of several systems (including respiration, swallowing and cough) as well as sensory motor reflex responses involving glossopharyngeal, pharyngeal, laryngeal, and tracheobronchial sensory receptors. Techniques for the clinical assessment of these reflexes are emerging and need to be examined for sensitivity and specificity in identifying laryngeal sensory disorders. Quantitative assessment methods for the diagnosis of sensory reductions and sensory hypersensitivity may account for laryngeal disorders, such as chronic cough, paradoxical vocal fold disorder, and muscular tension dysphonia. The development of accurate assessment techniques could improve our understanding of the mechanisms involved in these disorders.

Recurrent laryngeal nerve recovery patterns assessed by serial electromyography

OBJECTIVES/HYPOTHESIS

Following acute injury to the recurrent laryngeal nerve (RLN), laryngeal electromyography (LEMG) is increasingly being used to determine prognosis for recovery. The LEMG findings change during the recovery process, but the timing of these changes is not well described. In this canine study, LEMGs were obtained serially following model RLN injuries.

STUDY DESIGN

Animal Study.

METHODS

Thirty-six canine RLNs underwent crush (n = 6), complete transection with reanastomosis (n = 6), half-transection half-crush (n = 5), cautery (n = 5), stretch (n = 5), inferior crush (n = 4), or inferior transection with reanastomosis (n = 5) injuries. Injuries were performed 5 cm from cricoid or were 5 cm further inferior. Under light sedation, LEMG of thyroarytenoid muscles was performed monthly for 6 months following injury. At 6 months, spontaneous and induced vocal fold motion was assessed.

RESULTS

Except for the stretch injury, the remaining groups showed very similar recovery patterns. Fibrillation potentials (FPs) and/or positive sharp waves (PSWs; signs of bad prognosis) were seen in all cases at 1 month and lasted on average for 2.26 months (range = 1-4 months). Motor unit potentials of at least 2+ (scale = 0-4+; signs of good prognosis) were seen beginning at 3.61 months (range = 2-6 months). The stretch injury was less severe, with 3 of 5 showing no FPs/PSWs at 1 month; all recovered full mobility. Ten of the 36 thyroarytenoid muscles (27.8%) had 1 electromyograph showing both bad prognosis and good prognosis signs simultaneously at 2 to 4 months postinjury.

CONCLUSIONS

LEMG can be used to predict RNL recovery, but timing is important and LEMG results earlier than 3 months may overestimate a negative prognosis.

LEVEL OF EVIDENCE

NA Laryngoscope, 126:651-656, 2016.

Factors associated with the improvement of vocal fold movement: an analysis of LEMG and laryngeal CT parameters

The aim of this study is to elucidate the relationship of laryngeal electromyography (LEMG) and computed tomographic (CT) parameters to improve the prognosis of recurrent laryngeal nerve injury. 22 patients clinically suspected of having recurrent laryngeal nerve injury were examined with LEMG and CT studies. Bilateral thyroarytenoid (TA) muscles were examined and findings were interpreted by a single blind technique. Laryngeal CT image analysis of the ventricle dilation symmetry determined TA muscle atrophy. Finally, a follow-up laryngoscopic examination determined improvement of vocal fold movement. Ventricle dilation symmetry and the dichotomized TA muscle atrophy parameter significantly relate to the improvement of vocal fold movement (χ(2)=4.029, P=0.039, and χ(2)=3.912, P=0.048, respectively). When the severity of vocal fold impairment was classified as severe TA muscle atrophy or none/discrete MUAP recruitment, it was found to significantly relate with the improvement of vocal fold movement (χ(2)=6.712, P=.010). From this study, image analysis of the ventricle dilation symmetry to determine the severity of TA muscle atrophy shows promise for the improved prognosis of vocal fold immobility.

Investigation of Fatigue, Delayed-Onset Muscle Soreness, and Spectral-Based Cepstral Measurements in Healthy Speakers after Neuromuscular Electrical Stimulation

Objectives:

We observed whether 30 minutes of neuromuscular electrical stimulation applied to the necks of healthy speakers would result in significant acoustic changes and perceptions of fatigue and/or delayed-onset muscle soreness (DOMS).

Methods:

Twelve participants were assigned to experimental (n = 6; 3 male and 3 female) and control groups (n = 6; 3 male and 3 female). Neuromuscular electrical stimulation was applied to the anterior neck in the experimental group only. All participants produced 3 trials of the vowel / a/ and the Rainbow Passage before and after completing a 30-minute phonation protocol. Recorded samples were analyzed for measures of the cepstral peak prominence, the ratio of low- to high-frequency spectral energy, and their respective standard deviations. Perceptions of fatigue and DOMS were rated on visual analog scales before, 5 minutes after, and 24 hours after completion of the phonation protocol.

Results:

Statistically significant acoustic findings reflecting reduced relative sound pressure level, increased high-frequency noise, and phonatory instability were observed in the experimental group. In addition, reports of fatigue and DOMS were also reported by some participants.

Conclusions:

A 30-minute dosage may be too high for some people experiencing neuromuscular electrical stimulation for the first time.

Efficacy of laryngeal botulinum toxin injection: comparison of two techniques

OBJECTIVES/HYPOTHESIS

It is hypothesized that there is no difference in the effectiveness of botulinum toxin (BTX) injection between electromyography (EMG)-guided and non-EMG guided "point-touch" techniques in the treatment of adductor spasmodic dysphonia.

STUDY DESIGN

Retrospective chart review.

METHODS

Patients selected for evaluation underwent sequential treatment by one or both of the senior authors using two different injection techniques with similar BTX dilution and preparation. Data gathered included dose injected, injection effect, and presence and duration of breathiness and dysphagia after injection. Statistical analysis was performed used a generalized estimating equations model.

RESULTS

A total of 417 injections in 64 patients were analyzed. There was no difference in the rate of successful injections between the EMG-guidance group and the non-EMG guidance group (94.4% and 93.2%, respectively; P = .7).

CONCLUSIONS

This unique study demonstrates that efficacy of BTX does not necessarily depend on the method of injection used. In experienced hands, excellent clinical results can be achieved with either EMG-guided or non-EMG guided injection techniques.

Efficacy of laryngeal botulinum toxin injection: comparison of two techniques

OBJECTIVES/HYPOTHESIS

It is hypothesized that there is no difference in the effectiveness of botulinum toxin (BTX) injection between electromyography (EMG)-guided and non-EMG guided "point-touch" techniques in the treatment of adductor spasmodic dysphonia.

STUDY DESIGN

Retrospective chart review.

METHODS

Patients selected for evaluation underwent sequential treatment by one or both of the senior authors using two different injection techniques with similar BTX dilution and preparation. Data gathered included dose injected, injection effect, and presence and duration of breathiness and dysphagia after injection. Statistical analysis was performed used a generalized estimating equations model.

RESULTS

A total of 417 injections in 64 patients were analyzed. There was no difference in the rate of successful injections between the EMG-guidance group and the non-EMG guidance group (94.4% and 93.2%, respectively; P = .7).

CONCLUSIONS

This unique study demonstrates that efficacy of BTX does not necessarily depend on the method of injection used. In experienced hands, excellent clinical results can be achieved with either EMG-guided or non-EMG guided injection techniques.

[Neurolaryngology]

The neuroanatomy of voice and speech is complex. An intricate neural network is responsible for ensuring the main functions of the larynx: airway protection, cough and Valsalva production, and providing voice. Coordination of these roles is very susceptible to disruption by neurological disorders. Neurological disorders that affect laryngeal function include Parkinson's disease, stroke, amyotrophic lateral sclerosis, multiple sclerosis, dystonia and essential tremor. A thorough neurological evaluation should be routine for any patient presenting with voice complaints suggestive of neurogenic cause. Endoscopic visualisation of the larynx using a dynamic voice assessment with a flexible laryngoscope is a crucial part of the evaluation and ancillary tests are sometimes performed. Otolaryngologic evaluation is important in the diagnosis and treatment of neurological disorders that affect laryngeal function.

A single-centre retrospective review of unilateral and bilateral Dysport injections in adductor spasmodic dysphonia

We reviewed the results and side-effect profile of the Dysport preparation of botulinum toxin A (BTA) in the management of the adductor spasmodic dysphonia. We performed 272 injection episodes in 68 patients, 42 (62%) female, 26 (38%) male. A total of 116 of these injections were unilateral, and 156 were bilateral; 94% of the injections were considered to have been successful with a voice score of 2 or higher. The mean duration of effect (injection intervals) was 128.8 days in the unilateral cohort and 118.7 days in the bilateral (P > 0.05). We injected a relatively lower dose of BTA for unilateral injection episodes in our institution compared to those reported by others to produce comparable results and side-effect profiles.

[Dysphonia following glyphosate exposition]

Glyphosate is a commonly used nonselective herbicide which inhibits plant growth through interference with the production of essential aromatic amino acids. Toxicity for humans has been reported after suicidal ingestion. Here we describe a 26-year-old teacher who used glyphosate correctly but suffered from severe dysphonia after some hours. Laryngostroboscopy revealed decreased vocal fold mobility suggesting innervation impairment. The symptoms resolved spontaneously 6 weeks later and vocal fold mobility returned to normal. Glyphosate neurotoxicity has been discussed in the literature therefore, the dysphonia observed here may have been due to an intermittent neuropraxia of the laryngeal nerve. However, to our knowledge a similar case has not been reported in literature.

Unilateral versus bilateral thyroarytenoid Botulinum toxin injections in adductor spasmodic dysphonia: a prospective study

Objectives

In this preliminary prospective study, we compared unilateral and bilateral thyroarytenoid muscle injections of Botulinum toxin (Dysport) in 31 patients with adductor spasmodic dysphonia, who had undergone more than 5 consecutive Dysport injections (either unilateral or bilateral) and had completed 5 concomitant self-rated efficacy and complication scores questionnaires related to the previous injections. We also developed a Neurophysiological Scoring (NPS) system which has utility in the treatment administration.

Method and materials

Data were gathered prospectively on voice improvement (self-rated 6 point scale), length of response and duration of complications (breathiness, cough, dysphagia and total voice loss). Injections were performed under electromyography (EMG) guidance. NPS scale was used to describe the EMG response. Dose and unilateral/bilateral injections were determined by clinical judgment based on previous response. Time intervals between injections were patient driven.

Results

Low dose unilateral Dysport injection was associated with no significant difference in the patient's outcome in terms of duration of action, voice score (VS) and complication rate when compared to bilateral injections. Unilateral injections were not associated with any post treatment total voice loss unlike the bilateral injections.

Conclusion

Unilateral low dose Dysport injections are recommended in the treatment of adductor spasmodic dysphonia.

Recommendations of the Neurolaryngology Study Group on laryngeal electromyography

The Neurolaryngology Study Group convened a multidisciplinary panel of experts in neuromuscular physiology, electromyography, physical medicine and rehabilitation, neurology, and laryngology to meet with interested members from the American Academy of Otolaryngology Head and Neck Surgery, the Neurolaryngology Subcommittee and the Neurolaryngology Study Group to address the use of laryngeal electromyography (LEMG) for electrodiagnosis of laryngeal disorders. The panel addressed the use of LEMG for: 1) diagnosis of vocal fold paresis, 2) best practice application of equipment and techniques for LEMG, 3) estimation of time of injury and prediction of recovery of neural injuries, 4) diagnosis of neuromuscular diseases of the laryngeal muscles, and, 5) differentiation between central nervous system and behaviorally based laryngeal disorders. The panel also addressed establishing standardized techniques and methods for future assessment of LEMG sensitivity, specificity and reliability for identification, assessment and prognosis of neurolaryngeal disorders. Previously an evidence-based review of the clinical utility of LEMG published in 2004 only found evidence supported that LEMG was possibly useful for guiding injections of botulinum toxin into the laryngeal muscles. An updated traditional/narrative literature review and expert opinions were used to direct discussion and format conclusions. In current clinical practice, LEMG is a qualitative and not a quantitative examination. Specific recommendations were made to standardize electrode types, muscles to be sampled, sampling techniques, and reporting requirements. Prospective studies are needed to determine the clinical utility of LEMG. Use of the standardized methods and reporting will support future studies correlating electro-diagnostic findings with voice and upper airway function.

Management of Neurologic Disorders of the Larynx

Objectives:

I review the literature on management of neurologic disorders of the larynx.

Methods:

I reviewed the literature on laryngeal physiology, clinical evaluation of laryngeal function, and the clinical presentation and treatment of neurologic disorders that frequently affect the larynx.

Results:

Laryngeal function is complex, as this organ is important in breathing, speech, and swallowing. Coordination of these roles is very susceptible to disruption by neurologic disorders. Diagnosis of neurologic disease is primarily based on history and physical examination; however, the diagnosis of laryngeal dysfunction is frequently overlooked, because the larynx is not easily accessible to examination by non-otolaryngologists. Evaluation of laryngeal function includes listening to the voice, systematic observation of the larynx during speech and nonspeech tasks, and, sometimes, ancillary tests. Neurologic disorders that affect laryngeal function include Parkinson's disease, essential tremor, stroke, amyotrophic lateral sclerosis, multiple sclerosis, and dystonia. The otolaryngologist can sometimes provide treatment to specifically improve symptoms of laryngeal involvement.

Conclusions:

Otolaryngology consultation is important in the diagnosis and treatment of neurologic disorders that affect laryngeal function. The otolaryngologist should be able to perform a systematic evaluation of laryngeal and pharyngeal function, and should be aware of the clinical presentation of neurologic disorders that affect the larynx.

The Value of Laryngeal Electromyography in the Evaluation of Laryngeal Motion Abnormalities

SUMMARY

Laryngeal electromyography (EMG) functions routinely as a prognostic tool in the evaluation of vocal fold paralysis, as a guide for therapeutic injections into the laryngeal muscles, and more recently as an assessment tool in the evaluation of vocal fold paresis. This study investigates the clinical utility of laryngeal EMG as a diagnostic aid in the evaluation of movement disorders of the larynx in patients complaining of dysphonia. A retrospective chart review of all laryngeal EMGs performed at a tertiary laryngology referral center over a 13-month period was performed. All laryngeal EMGs were performed to evaluate laryngeal motion abnormalities in dysphonic patients. Thirty-seven laryngeal EMGs were completed during this study period. Analysis of the data revealed that the medical treatment plan changed as a result of findings on laryngeal EMG in 10/37 patients (27.0%); laryngeal EMG guided and/or confirmed the course of treatment in 12/37 patients (32.4%) and did not change the treatment plan in 15/37 patients (40.5%). Laryngeal EMG is a useful diagnostic tool that, in this study, contributed significantly to and helped guide the evaluation and management of motion disorders in the larynx of dysphonic patients.

Diagnostic Testing for Vocal Fold Paralysis: Survey of Practice and Evidence-Based Medicine Review

OBJECTIVES/HYPOTHESIS

Vocal fold paralysis continues to be a dominant topic in laryngology. Although the majority of cases can be attributed to a known etiology, a significant number of patients present without a clear precipitating event. Over 1,500 studies regarding vocal fold paralysis exist in the medical literature, although only a small percentage report on the use of serum or radiographic testing for the evaluation of idiopathic paralysis. Despite this, patients are routinely subjected to diagnostic evaluation to investigate the underlying cause. To characterize contemporary practice, a national survey of the American Broncho-Esophagological Association (ABEA) membership was undertaken. It is hypothesized that the current practice of diagnostic testing for idiopathic vocal fold paralysis is not well supported by an evidence-based medicine (EBM) review of the available medical literature.

STUDY DESIGN

The authors conducted a national survey, systematic EBM review of existing literature.

METHODS

Surveys were mailed to all active ABEA members; responses regarding practice specialization as well as serum/radiographic diagnostic preferences for idiopathic vocal fold paralysis were tabulated and subjected to statistical analysis. To compare contemporary practice with evidence in the available literature, an EBM review was first performed. Articles for evaluation were selected from a Medline search of English-language abstracts related to adult vocal fold paralysis. The publications were individually reviewed and an EBM level and grade were assigned and compared with the survey results.

RESULTS

Eighty-four of 249 active members responded with 76 (31%) replies submitted for analysis. Specific serum tests were advocated by 41 of 76 (54%) respondents, although the majority (52 of 65 [80%]) felt that they were only "occasionally" or "never" necessary. The most common tests were rheumatoid factor (38%), Lyme titer (36%), erythrocyte sedimentation rate (34%), and antinuclear antibody (33%). Fifty-one of 71(72%) felt that computed tomography (CT) was "always" or "often" necessary and 50 of 72 (69%) replied that chest radiography (CXR) was "always" or "often" necessary. There was no significant difference between CT and CXR ordering (P < .51). In contrast, magnetic resonance imaging (MRI) was described as "always" or "often" necessary in 28 of 71 (39%) of the surveys, significantly less than CT (P < .0001). There was no statistical impact of practice specialization on ordering of serum tests (P = .25) or imaging (P = .50 for CT; P = .46 for CXR; P = .45 for MRI). Following analysis of 1,510 vocal fold paralysis abstracts, 19 publications were found to be appropriate for an EBM review of serum testing with 15 available for review of radiographic imaging. Only one study presented level III evidence; the remainder were levels IV and V comprised of retrospective series and case reports. The evidence supporting serum or radiographic testing toward the evaluation of idiopathic vocal fold paralysis is given an overall grade of "C."

CONCLUSIONS

Serum and radiographic testing for the evaluation of vocal fold paralysis is supported by grade "C" evidence only. There are no existing prospective studies estimating the clinical impact of testing on diagnosis or patient outcome. Current practice, as estimated by a survey of the ABEA membership, is not well founded for serum testing and only by retrospective case series with regard to imaging. Further study into the nature of idiopathic vocal fold paralysis and outcomes assessment of diagnostic paradigms may improve clinical practice.

Mild Vocal Fold Paresis: Understanding Clinical Presentation and Electromyographic Findings

The implications of mild vocal fold hypomobility are incompletely understood. This study describes the clinical, electromyographic, and probable etiologic findings in patients who presented with complaints of dysphonia and whose physical examination revealed vocal fold paresis as a factor possibly contributing to their voice complaints. A retrospective chart review of all patients who presented to a tertiary laryngology referral center over a 13-month period, who had a clinical diagnosis of mild vocal fold hypomobility and who underwent laryngeal electromyography, were included in the study. A total of 22 patients completed the medical evaluation of their voice complaint. Of these patients, 19 (86.4%) were found to have evidence of neuropathy on laryngeal electromyography. The clinical picture indicated the following probable origins for the vocal fold paresis: goiter/thyroiditis (7/22 or 31.8%), idiopathic (4/22 or 18.2%), viral neuritis (4/22 or 18.2%), trauma (3/22 or 13.6%), and Lyme's disease (1/22 or 4.5%). This article describes the clinical entity of mild vocal fold hypomobility and associated flexible laryngoscopic, rigid strobovideolaryngoscopic, and laryngeal electromyographic findings.

Applying the Voice Handicap Index (VHI) to Dysphonic and Nondysphonic Hebrew Speakers

OBJECTIVE

To evaluate a translated version of the Voice Handicap Index (VHI) as a diagnostic tool for people with and without a laryngeal pathology, among Hebrew speakers.

STUDY DESIGN

Parallel group design.

METHODS

The VHI was translated and adapted to Hebrew. The translated version was, then, administered to a group of 182 patients with various laryngeal pathologies and a control group of 171 people with no laryngeal pathology. Based on the participants' responses to the VHI, statistical analyses were, initially, performed to assess validity and reliability, and then to evaluate group differences between the pathological and control groups and among the different pathological groups included in the study.

RESULTS

Statistical analyses showed high reliability values of the Hebrew version of the VHI (overall Cronbach's alpha r = 0.976). Participants' scores were not affected by their age (P = 0.156) or gender (P = 0.261). The participants in the control group obtained significantly lower scores on the overall VHI score, as well as on all three subscale scores, in comparison with the pathological group (P < 0.001). In addition, within the pathological group, patients with neurogenic pathologies received higher scores than all other pathological groups, whereas patients with laryngeal inflammation received lower scores than all other pathological groups (P < 0.05).

CONCLUSION

The VHI is a powerful tool for quantifying patients' perceptions of their voice handicaps, and it maintained its power across translation. The VHI was shown to be valuable for the assessment of speakers with, as well as without laryngeal pathologies.

Botulinum toxin therapy of laryngeal muscle hyperactivity syndromes: comparing different botulinum toxin preparations

Spasmodic dysphonia (SD) is a focal dystonia characterized by a strained, strangled voice. Botulinum toxin is a symptomatic treatment for SD and has become the mainstay of therapy over the last two decades. In this manuscript, we briefly review different laryngeal muscle hyperactivity syndromes, their injection techniques and toxins currently available. Adductor SD is the most common indication for botulinum toxin treatment in the larynx. All studies report similar results with regard to improvement, patient satisfaction and side effects. We describe different injection techniques to treat this disorder such as the percutaneous, transoral, transnasal, point-touch techniques. In abductor SD, a subtype of SD, the treatment is aimed at the posterior cricoarytenoid muscle. Other applications of botulinum toxin in the larynx include spasmodic laryngeal dyspnea and voice tremors. We also review injection techniques, the different toxin types used, and toxin doses.

Diagnostic tools in laryngology

PURPOSE OF REVIEW

Laryngology has become recognized as a subspecialty within the field of otolaryngology-head and neck surgery over the course of the past 30 years. The evolution of laryngology stems primarily from our better understanding of the physiology of vocal production, society's increased reliance on oral communication in industry, and the resultant demand for improvements in diagnostic and therapeutic protocols to enhance vocal performance. The purpose of this review is to describe current advances in diagnostic tools in laryngology that contribute to our understanding of vocal physiology and our ability to improve quality of life as it relates to vocal performance.

RECENT FINDINGS

Diagnostic tools in laryngology allow the clinician the ability to assess the vibratory function of the vocal folds, evaluate laryngeal structure and airway patency, assess glottal and pulmonary airflow, assess the neurologic integrity of the vocal folds, analyze the quality of the voice signal, and assess the degree of functional disability as it relates to laryngeal pathology.

SUMMARY

Primary advances in diagnostic laryngology include improvements in laryngoscopy techniques, imaging, electromyography, aerodynamic testing, acoustic analysis, and functional assessment, each of which is improving our ability to understand, diagnose, and treat a wider spectrum of voice, airway, and swallowing disorders.