Analysis of Laryngoscopic Features in Patients With Unilateral Vocal Fold Paresis

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1 The Laryngoscope VC 2015 The American Laryngological, Rhinological and Otological Society, Inc. Analysis of Laryngoscopic Features in Patients With Unilateral Vocal Fold Paresis Peak Woo, MD; Arjun K. Parasher, MD; Tova Isseroff, MD; Amanda Richards, MBBS, FRACS; Mark Sivak, MD Objectives/Hypothesis: The diagnosis of paresis in patients with vocal fold motion impairment remains a challenge. More than 27 clinical parameters have been cited that may signify paresis. We hypothesize that some features are more significant than others. Study Design: Prospective case series. Methods: Two laryngologists rated laryngoscopy findings in 19 patients suspected of paresis. The diagnosis was confirmed with laryngeal electromyography. A standard set of 27 ratings was used for each examination that included movement, laryngeal configuration, and stroboscopy signs. A Fisher exact test was completed for each measure. A kappa coefficient was calculated for effectiveness in predicting the laterality of paresis. Results: Left-sided vocal fold paresis (n 5 13) was significantly associated with ipsilateral axis deviation, thinner vocal fold, bowing, reduced movement, reduced kinesis, and phase lag (P <.05). Right-sided vocal fold paresis (n 5 6) was significantly associated with ipsilateral shorter vocal fold, axis deviation, reduced movement, and reduced kinesis (P <.05). Using these key parameters, the senior author was accurately able to diagnose the side of paresis in 89.5% of cases for a kappa coefficient of Conclusions: Of the multiple features on laryngoscopy, glottic configuration, ipsilateral thin vocal fold, vocal fold bowing, reduced movement, reduced kinesis, and phase lag were more likely to be associated with vocal fold paresis. Key Words: Vocal fold paresis, vocal fold motion abnormality, laryngoscopy, stroboscopy. Level of Evidence: 4 Laryngoscope, 126: , 2016 From the Department of Otolaryngology Head and Neck Surgery (P.W., A.K.P., T.I., A.R.) and the Department of Neurology (M.S.), Icahn School of Medicine at Mount Sinai, New York, New York, U.S.A. Editor s Note: This Manuscript was accepted for publication October 27, Presented as a poster at the American Laryngological Association s 2015 Annual Meeting, Boston, Massachusetts, U.S.A., April 22 23, The authors have no funding, financial relationships, or conflicts of interest to disclose. Send correspondence to Arjun K. Parasher, MD, 1 Gustave Levy Place, Box 1189, New York, NY arjun.parasher@mountsinai.org DOI: /lary INTRODUCTION The diagnosis of vocal fold paresis remains challenging. In their review of missed diagnosis, Rafii et al. noted vocal fold paresis was the second most common missed diagnosis in patients diagnosed with reflux that failed to respond to treatment. 1 Paresis may represent the diagnosis for a subset of patients presenting with glottal insufficiency symptoms of vocal fatigue, breathy voice quality, cough, and strain. 2 Vocal fold paresis may be an underdiagnosed pathology. In a study of elderly patients, paresis was found in a high percentage of patients undergoing laryngeal electromyography (LEMG). 3 However, most clinicians make the diagnosis of vocal fold paresis on a clinical basis without performing LEMG. In a practice survey of laryngologists, Wu and Sulica noted the majority depended on video strobelaryngoscopy (VSL) findings to make the diagnosis of paresis. 4 The key features on VSL that were thought to be important were: slow vocal fold motion, decreased adduction or abduction and decreased vocal fold tone. Other authors have cited vocal fold bowing, unilateral hypomobility, unilateral vocal fold bowing, bilateral bowing, bilateral hypomobility, axial rotation, 5 and asymmetry of the mucosal wave. 6 In addition, laryngoscopy findings in paresis confirmed on LEMG can include asymmetry between left and right vocal fold mucosal wave, incomplete glottal closure, and impaired mobility of the arytenoid cartilage. 7 No less than 27 separate features could be noted on videostroboscopy that may indicate paresis. The term paresis may be defined in many ways. In patients with unilateral vocal fold motion asymmetry, the differential diagnosis may cause the clinician to include the diagnosis of paresis. In these patients, the diagnosis of paresis is suspected mainly on endoscopic findings of asymmetric vocal fold movement (reduced diadochokinesis, incomplete abduction or adduction), glottis configuration (vocal fold bowing, thin vocal fold, shorter vocal fold), or on stroboscopy (open phase dominant pattern, lateral to medial phase shift, incomplete closure). 4 An alternate way to define paresis is using LEMG criteria. 8 LEMG criteria include positive findings of: laryngeal irritability (insertional irritability, positive sharp waves, and complex repetitive discharges), motor 1831

2 Category Glottis configuration Movement Stroboscopy TABLE I. Videostroboscopy Features Evaluated. Feature Shorter vocal fold, axis deviation, thin vocal fold, bowing, asymmetric pyriform opening, lower vocal fold Reduced movement, reduced kinesis, pharyngeal squeeze Phase lag, open phase dominant,* incomplete closure,* reduced, glottic gap anterior,* glottic gap middle,* glottic gap posterior* *All features require bilateral evaluation except for those indicated by the asterisks. unit abnormalities (reduced, units firing fast and out of sequence, and reduced motor units), and motor unit morphology abnormalities (giant potentials,, nascent units). 9 LEMG is a difficult test to do well. It is dependent on subjective interpretation and often requires multidisciplinary input from neurology for interpretation and otolaryngology for insertion. This expertise is not commonly available. Although the clinician may use the term suspected paresis based on endoscopic criteria, the finding of positive LEMG findings is usually considered more secure in the diagnosis of paresis. 10 At present, limited data exist to correlate a positive LEMG finding to the variety of endoscopic findings that prompted the clinical diagnosis of paresis. If the multiple clinical findings that prompted the clinical diagnosis of paresis could be simplified and correlated to LEMG findings, the clinician may be able to more secure in the diagnosis of paresis without the need for LEMG. Although there are many papers that suggest signs of paresis, there is little literature to give clinical weighting to these findings. Simplification and identification of the most pertinent configuration, movement, and stroboscopy findings potentially would enable improved accuracy of clinical diagnosis, avoidance of unnecessary medical interventions, and reduced morbidity. The purpose of this study was to identify patients who have unilateral vocal fold paresis confirmed by LEMG studies and correlate them to laryngoscopy features. We hypothesized that some configuration, movement, and vibration features on laryngoscopy are more likely to be present than others in unilateral vocal fold paresis. By focusing on these key features, the identification of vocal fold paresis on laryngoscopy may be made easier. MATERIALS AND METHODS Between 2013 and 2014, 25 symptomatic subjects with mobile vocal folds suspected of having unilateral vocal fold paresis were prospectively recruited for LEMG. These 25 patients were all initial examinations with no prior medical or voice therapy treatment. None of the patients had received a diagnosis or treatment before this initial examination. Although many had seen otolaryngologists prior, the diagnosis of vocal fold paresis was not made. All were symptomatic in having acute complaints related to voice with symptoms of hoarse voice and vocal fatigue. Each subject was a symptomatic voice-disordered patient with unilateral vocal fold motion disturbance. The diagnosis for suspected paresis was based on clinical symptoms of glottic incompetence and laryngeal videostroboscopic examination. Of the 25 patients, two had prior surgical trauma, with one having a prior thyroidectomy and the other a prior anterior approach for cervical disc disease. The remaining 23 patients were considered to have idiopathic vocal fold paresis. The criteria for diagnosis of paresis is based on the literature reports of abnormal vocal fold motion, abnormal glottis configuration, and abnormal vocal fold vibration. For each subject, the VSL was done prior to LEMG evaluation. The examination included observation of three distinct categories: glottis configuration, evaluation of kinesis, and videostroboscopy. All the subjects were examined by distal chip-tip flexible laryngoscopy with videostroboscopy (Pentax VNL1170-K, RLS 9100B; Pentax Medical, Montvale, NJ). Firstly, for glottis configuration, the examination recording included observations of static laryngoscopy features suggestive of paresis that included shorter vocal fold, thin vocal fold, vocal fold bowing, level difference, and open pyriform sinus. Secondly, movement and diadochokinesis was assessed by phonation with alternating deep inspiration (/eee/ sniff gesture), whistle, and cough. From this, assessment was made regarding reduced movement, reduced kinesis, or reduced pharyngeal squeeze. Finally, the stroboscopy examination was used to determine the presence of a glottal gap at the most closed phase, open phase dominant pattern, reduced, incomplete closure, or phase lag. The VSL rating form is shown in Table I. Two laryngologists, (P.W., A.R.) rated the VSL together, and when there was agreement, noted the findings as being present. The data were entered into a spreadsheet. The patient then underwent LEMG at a later setting. The LEMG was performed together with a laryngologist (P.W.) and interpretation done by an American Association of Neuromuscular and Electrodiagnostic Medicine board-certified neurologist (M.S.) who was blinded to the clinical findings as to site and side of lesion. Four intrinsic laryngeal muscles (the paired cricothyroid and thyroarytenoid muscles) were sampled for each subject. The needle used was a 26-gauge concentric bipolar needle (Alpine BioMed, Skovlunde, Denmark; 50 mm mm). Standard validation gestures for each muscle activation were used. After the LEMG, the patients were categorized to have normal examination, unilateral recurrent nerve paresis, unilateral vagal nerve paresis, bilateral paresis, or other. The 19 subjects with LEMG-confirmed unilateral recurrent laryngeal nerve (RLN) paresis or unilateral vagal nerve paresis were selected for further analysis. LEMG diagnosis of paresis was based on the findings of denervation potentials, abnormal, and motor unit morphology. Table II tabulates the 19 subjects and their LEMG findings. RLN paresis was defined by findings in the thyroarytenoid muscle only, whereas vagal paresis was determined by findings in both the cricothyroid and thyroarytenoid muscles. Four of 19 patients had acute denervation potentials such as fasciculation, fibrillation potentials, and positive sharp wave. All 19 patients had abnormalities that included reduced, units firing out of sequence, fast firing units, and reduced number of voluntary units. Each of the 19 patients with paresis had a finding of decreased. Thirteen of the 19 subjects had motor unit morphology abnormalities such as giant potentials and. Multiple criteria from each category of acute denervation potential, abnormality, and motor unit morphology abnormality were used by the neurologist to make the diagnosis of unilateral paresis. The 19 patients with unilateral paresis, defined as either unilateral RLN or vagal paresis, were divided into the right and left side and analyzed versus the laryngoscopy findings. A 1832

3 TABLE II. LEMG Findings in Patients With Unilateral Vocal Fold Paresis. Case Weeks Site of Paresis Acute Recruitment Morphology RLN Voluntary units, fast firing units, decreased units, decreased, decreased 2 60 RLN Decreased 3 24 RLN Decreased 4 6 RLN Fast firing units, decreased units, decreased 5 36 RLN Irritable, fibrillation potentials Fast firing units, decreased 6 4 RLN Fast firing units, decreased units, decreased 7 20 RLN Fasciculations Decreased 8 48 RLN Decreased units, decreased, decreased 9 24 RLN Decreased units, decreased, decreased 10 5 Vagus Fast firing units, decreased 11 8 Vagus Decreased units, decreased Vagus Irritable, fibrillation potentials, positive sharp waves Voluntary units, fast firing units, decreased units, decreased, decreased 13 6 Vagus Fasciculations Decreased 14 4 Vagus Fast firing units, decreased Vagus Decreased units, decreased 16 6 Vagus Fast firing units, decreased units, decreased 17 2 Vagus Decreased Vagus Decreased 19 3 RLN Decreased units, decreased LEMG 5 laryngeal electromyography; RLN 5 recurrent laryngeal nerve. Fisher exact test was completed for each measure. A kappa coefficient was calculated for effectiveness in predicting the laterality of paresis. The institutional review board at the Icahn School of Medicine at Mount Sinai approved this study. A P value of.05 or less was considered significant in the laryngoscopy finding for predicting the laterality of paresis found on LEMG. RESULTS Twenty-five patients were suspected of having unilateral paresis with mobile vocal folds. Two had a normal LEMG and four had evidence of bilateral denervation. For this reason, these six patients were excluded from the analysis. The remaining patients had evidence of unilateral vocal fold paresis. Ten had evidence of unilateral RLN involvement with abnormal electrical signals in the thyroarytenoid (TA) muscle. The rest had vagal involvement with signal abnormalities in the cricothyroid and TA muscles. Left-sided vocal fold paresis (n 5 13) was significantly associated with ipsilateral axis deviation, thinner vocal fold, bowing, reduced movement, reduced kinesis, and phase lag (P <.05). Right-sided vocal fold paresis (n 5 6) was significantly associated with ipsilateral shorter vocal fold, axis deviation, reduced movement, and reduced kinesis (P <.05). VSL finding of ipsilateral axis deviation, reduced movement, and reduced kinesis were significant findings in both right- and left-sided paresis, whereas the rest were found in only one group. Because twice as many subjects had left-sided paresis versus the right, the statistics are reported for each finding relative to the side of paresis and are different between the two sides. For left-sided vocal fold paresis, a thin ipsilateral vocal fold (P ) and lower ipsilateral vocal fold (P ) displayed a trend toward statistical significance. For right-sided vocal fold paresis, ipsilateral phase lag (P ) and decreased (P

4 TABLE III. Clinical Parameters More Likely to Be Useful in Identifying Vocal Fold Paresis. Category Glottis configuration Movement Stroboscopy Finding Axis deviation, shorter vocal fold, thinner vocal fold, vocal fold bowing Abnormal abduction or adduction, kinesis Phase lag, open phase dominant* *Found in 16 of 19 patients with vocal fold paresis, but does not assist in determining side of laterality..0709) approached statistical significance. The remaining clinical features did not approach statistical significance. Of the five stroboscopy measures that did not specify laterality, open phase dominant was the most common finding, manifesting in 16 of 19 patients. Using these key parameters, the senior author was accurately able to diagnose the side of paresis in 89.5% of cases for a kappa coefficient of Table III lists the laryngoscopy features that showed statistical significance in prediction of paresis for either side. Figures 1 and 2 show examples of the key endoscopic findings that supported the finding of unilateral vocal fold paresis on LEMG. These include axis deviation, bowing, vocal fold thinning, shorter vocal fold, phase lag, and reduced kinesis. By dividing the findings into glottic configuration abnormalities (axis deviation, bowing, shorter vocal fold, and thin vocal fold), movement abnormalities (reduced abduction and reduced diadochokinesis), and stroboscopy abnormalities (phase lag), one can assess the relative frequency of multiple types of findings in the paresis patients. In this series, 11 subjects had abnormality in all three categories, six had abnormalities in two of three categories, and two had abnormalities in only one category. In tabulation of the frequency of each classification of abnormalities, abnormal configuration was present in 18/19 subjects, movement abnormalities were present in 18/19 subjects, and stroboscopy abnormalities were present in 10/19 subjects. Thus, multiple category findings were present in 18 of 19 subjects. The finding of configuration and movement abnormalities was more commonly found than stroboscopy abnormalities. DISCUSSION We found from this study a relatively poor agreement between the laryngoscopy findings and LEMG findings in patients with vocal fold paresis. Six of the patients (24%) had LEMG findings showing normal LEMG or bilateral paresis, whereas the clinical diagnosis was unilateral paresis. In analysis of the 19 subjects with unilateral paresis, the senior author correctly predicted the side of paresis in 89.5% of cases for a kappa coefficient of 0.78, signifying substantial agreement. 11 Table III describes the VSL findings that reached statistical significance in the diagnosis of unilateral vocal fold paresis. Our study shows that despite a high index of suspicion and careful stroboscopy examination, a large discrepancy remains between the LEMG findings and the clinical diagnosis. Therefore, the diagnosis of paresis would better be classified as a clinical diagnosis of paresis based on endoscopy versus a diagnosis of paresis based on LEMG criteria. In a study of laryngoscopy and LEMG findings, Dejonckere stated that vocal fold paresis demonstrates reduced vocal fold mobility. 12 He noted that, although the majority of the patients in his series had LEMG findings of partial denervation, many had normal LEMG findings. Conversely, many patients with good innervation as defined by LEMG signals displayed no evidence of movement despite good muscle tone and activity. These findings further complicate the diagnosis of vocal fold paresis. Is vocal fold paresis defined as a clinical entity of glottic incompetence with reduced or asymmetric motion or as an electrophysiological diagnosis of denervation and reinnervation? In the clinical diagnosis of vocal fold paresis, most authors have used laryngoscopy findings to define possible presence of paresis. Most authors also go on to recommend LEMG to refine the diagnosis. 4,5,10,13,14 Despite the literature suggesting LEMG is useful in the diagnosis of paresis, it is unlikely it will become standard for clinicians in the diagnosis of paresis. Firstly, LEMG interpretation is subjective and requires experience. Secondly, the testing and interpretation requires an interdisciplinary collaboration. Simply put, needle placement is typically completed by a laryngologist, whereas the interpretation is provided by a neurologist. As a result, without better diagnostic tools, the clinical diagnosis of paresis will be continue to be based primarily on endoscopy and clinical suspicion. Fig. 1. Left vocal fold paresis displaying findings of (A) left thin, bowed vocal fold with left axis deviation, (B) left vocal fold shortening, and (C) left vocal fold phase lag. 1834

5 Fig. 2. A series of vocal fold images displaying reduced right-sided kinesis. The left vocal fold showed increased excursion with greater movement than the right. It may be best to define laryngeal asymmetry and evidence of glottal incompetence not verified by site of lesion testing or LEMG as suspected paresis, whereas patients with electrophysiological evidence of paresis may then be subcategorized to site and prognosis. By doing so, the nomenclature of vocal fold paresis may be further refined to improve discussion of treatment, outcome, or research. Because the majority of patients carrying the diagnosis of paresis will be based on clinical and endoscopic criteria, sharpening the endoscopic criteria may be of value in the diagnosis of paresis. The endoscopic criteria to diagnosis paresis have been quite disparate. Many authors have noted associated lesions in patients with paresis including granuloma, pseudo cyst, polyp, nodules, and muscle tension dysphonia. Laryngoscopy evaluation that suggests unilateral paresis may be divided into three distinct categories: glottal configuration, kinesis or movement, and stroboscopy evidence of vibration and competence. As noted by Sulica and Blitzer, paresis patients present with glottic insufficiency. 14 Koufman and Postma noted bowing and axis deviation and hypomobility on abduction greater than adduction. 5 Meyer and Hillel 15 also noted the difficulty of deciphering vocal fold motion asymmetry, and furthermore, in determining the possibility of neurological causes. Sataloff and Rubin observed that patients with subtle movement differences can be unmasked by stress testing. 16 They advocated repetitive phonatory tasks to fatigue patients vocally, and thereby elicit signs of subtle paresis. Thus, both configuration and movement differences between the two sides have been used to characterize patients with suspected paresis. More difficult is the use of stroboscopy features to identify paresis. Sulica and Blitzer studied videostroboscopy findings of vibratory asymmetry in mobile vocal folds, an indicator for vocal fold paresis. Their study showed that vibratory asymmetry on stroboscopy examination was associated with paresis, but was a poor predictor the side of paresis. 14 With so many features and subtle changes possible, there are no data supporting which laryngoscopy features are most predictive of paresis. Even among experts with many years of practice, there is disagreement on the significance of some laryngoscopy features. In a survey of practicing laryngologists, Wu and Sulica noted that the majority of laryngologists believed abnormalities of gross vocal fold motion were more predictive than stroboscopy signs followed by glottis configuration differences. 4 Furthermore, it was not clear if the majority of laryngologists depended on one or multiple findings to make the diagnosis of paresis. From this study, we believe that simplifying the observations can help to stratify the possible findings, identify the most predictive measures, and improve clinical diagnostic accuracy. Our study identifies that the laryngoscopy features that enable diagnosis of paresis and determination of laterality to be glottis configuration (ipsilateral axis deviation, thinner vocal fold, and bowing), kinesis (ipsilateral reduced movement, reduced kinesis), and from stroboscopy (ipsilateral phase lag). Open phase dominance is a common finding in patients with paresis, but does not assist in the determination of laterality. Of note, the findings of axis deviation, reduced kinesis, and thin vocal folds were present in patients with both right and left-sided paresis. In patients suspected of paresis, a protocol of fiberoptic examination with systematic query of glottic configuration abnormalities, movement abnormalities, and stroboscopy abnormalities should be instituted. Configuration changes such as bowing, axis deviation, and thin vocal folds should be evaluated. Systematic examination of vocal fold motion via fiberscope examination of vocal fold motion that includes, rapid diadochokinesis, cough, and phonation should be recorded and reviewed. The examination of kinesis should include both observation of degree of vocal fold abduction as well as kinesis of movement between the two sides. Kinesis being whether the vocal folds move at the same speed when viewed in adduction and abduction. Finally, the stroboscopy should look at asymmetric lateral to medial phase differences between the two vocal folds during sustained phonation. In this series, multiple findings from each category of configuration, movement, and stroboscopy were used to support the clinical diagnosis of paresis. In our study, abnormal configuration was present in 18/19 subjects, movement abnormalities were present in 18/19 subjects, and phase lag abnormalities were present in 10/19 subjects. Thus, findings from at least two categories were present in 18 of 19 subjects with unilateral vocal fold paresis. The finding of configuration and movement abnormalities being more commonly found than phase lag abnormalities. 1835

6 As a result, we believe multiple supportive findings from each category should be present before the diagnosis of paresis is made. By using these criteria, the clinical diagnosis may be more likely to be associated with a positive LEMG finding of unilateral nerve injury. To reduce the over- and underdiagnosis of paresis, we feel features should be present from at least two of the three categories to support the diagnosis. If only one category is present, LEMG should be considered to better define the diagnosis. As in all patients with subtle abnormalities, careful follow-up for pseudoparesis such as Parkinson s, myasthenia gravis, and presbyphonia should be done in patients with suspected glottal incompetence, but no definite evidence of paresis. The limitations of this study include that these findings are from a single institution experience with laryngoscopy and LEMG. The laryngoscopy findings are based on two laryngologists with similar training backgrounds. Therefore, the conclusions from this study results should be considered preliminary. The limited number of subjects means statistical analysis using multivariate analysis is impractical. Future studies are needed. In particular, a study with multiple rater evaluations would enable the clinical diagnosis of paresis to be better refined. CONCLUSION Laryngoscopy evidence of unilateral vocal fold paresis can be categorized by features of glottis configuration, reduced movement, and stroboscopy evidence of vibratory asymmetry. This study shows that the multiple laryngoscopy features can be distilled to observations of ipsilateral axis deviation, thin vocal fold, bowing, reduced movement, reduced kinesis, and phase lag. The presence of observations from at least two of the three categories should be present for clinical diagnosis. Findings from only one category should be confirmed by LEMG. BIBLIOGRAPHY 1. Rafii B, Taliercio S, Achlatis S, Ruiz R, Amin MR, Branski RC. Incidence of underlying laryngeal pathology in patients initially diagnosed with laryngopharyngeal reflux. Laryngoscope 2014;124: Bielamowicz S, Stager SV. Diagnosis of unilateral recurrent laryngeal nerve paralysis: laryngeal electromyography, subjective rating scales, acoustic and aerodynamic measures. Laryngoscope 2006;116: Gregory ND, Chandran S, Lurie D, Sataloff RT. Voice disorders in the elderly. J Voice 2012;26: Wu AP, Sulica L. Diagnosis of vocal fold paresis: current opinion and practice. Laryngoscope 2015;125: Koufman JA, Postma GN, Cummins MM, Blalock PD. Vocal fold paresis. Otolaryngol Head Neck Surg 2000;122: Kitzing P. Stroboscopy a pertinent laryngological examination. J Otolaryngol 1985;14: Stager SV. Vocal fold paresis: etiology, clinical diagnosis and clinical management. Curr Opin Otolaryngol Head Neck Surg 2014;22: Blitzer A, Crumley RL, Dailey SH, et al. Recommendations of the Neurolaryngology Study Group on laryngeal electromyography. Otolaryngol Head Neck Surg 2009;140: Faaborg-Andersen K, Briess FB, Brewer DW. Phonation: clinical testing versus electromyography. Acta Otolaryngol Suppl 1960;158: Rickert SM, Childs LF, Carey BT, Murry T, Sulica L. Laryngeal electromyography for prognosis of vocal fold palsy: a meta-analysis. Laryngoscope 2012;122: Landis J, Koch G. The measurement of observer agreement for categorical data. Biometrics 1977;33: Dejonckere PH. Unilateral paralysis of the vocal fold: correlation between laryngoscopy and electromyography [in French]. Folia Phoniatr Basel 1993;45: Stager SV, Bielamowicz SA. Using laryngeal electromyography to differentiate presbylarynges from paresis. J Speech Lang Hear Res 2010;53: Sulica L, Blitzer A. Vocal fold paresis: evidence and controversies. Curr Opin Otolaryngol Head Neck Surg 2007;15: Meyer TK, Hillel AD. Is laryngeal electromyography useful in the diagnosis and management of vocal fold paresis/paralysis? Laryngoscope 2011; 121: Rubin AD, Praneetvatakul V, Heman-Ackah Y, Moyer CA, Mandel S, Sataloff RT. Repetitive phonatory tasks for identifying vocal fold paresis. J Voice 2005;19: