[Analysis of vocal fold movement characteristics in patients with laryngeal neurogenic injury].

Objective:To analyze the characteristics of vocal fold movement and glottic closure in patients with laryngeal neurogenic injury. Methods:A total of 185 patients with vocal fold paralysis diagnosed by laryngeal electromyography as neurogenic damage to cricothyroid muscle, thyreoarytenoid muscle and posterior cricoarytenoid muscle were enrolled, they were divided into unilateral vocal fold paralysis group and bilateral vocal fold paralysis group, respectively, and superior laryngeal paralysis group, recurrent laryngeal nerve paralysis group and vagal nerve paralysis group according to nerve injury. The characteristics of vocal fold movement and glottic closure were analyzed under strobe laryngoscope. The qualitative evaluation of vocal fold movement was fixed vocal fold, reduced vocal fold movement and normal vocal fold movement, and the qualitative evaluation of glottic closure was glottic closure and glottic imperfection. The results were analyzed statistically. Results:The proportion of normal, reduced and fixed vocal fold motion in bilateral vocal fold paralysis group was significantly different from that in unilateral vocal fold paralysis group（P<0.05）, the composition of normal and reduced vocal fold motion in bilateral vocal fold paralysis group（47.70%） was significantly greater than that in unilateral vocal fold paralysis group（12.27%）. There was no significant difference between the proportion of glottic closure and glottic imperfecta in bilateral vocal fold paralysis group and unilateral vocal fold paralysis group（P<0.05）. The proportion of decreased vocal fold motion in superior laryngeal nerve paralysis group（50.00%） was higher than that in recurrent laryngeal nerve paralysis group（9.32%） and vagal nerve paralysis group（9.00%）. The proportion of decreased and fixed vocal fold motion in superior laryngeal nerve paralysis group, recurrent laryngeal nerve paralysis group and vagal nerve paralysis group was statistically significant（P<0.05）.There was no significant difference in glottic closure among the three groups（P<0.05）. Conclusion:Vocal fold movement characteristics of patients with laryngeal neurogenic injury were mainly vocal fold fixation, or normal or weakened vocal fold movement. There may be missed diagnosis of unilateral vocal fold paralysis in clinical practice. In half of the patients with superior laryngeal nerve palsy, vocal fold movement is characterized by vocal fold fixation.

The mechanism of action for laryngeal manual therapies: the need for an update.

PURPOSE OF REVIEW: To propose a pathway for expanding the understanding of potential mechanisms of action with laryngeal-based manual therapy (LMT) for muscle tension dysphonia (MTD). This review may help determine if current LMT literature has kept up with advances in the more general manual therapy (MT) findings. RECENT FINDINGS: Studies over the past thirty years, including recently published articles, have confirmed the efficacy of various manual therapy interventions in treating MTD. However, gaps exist between current LMT literature and that being presented in the more general MT field. Instead of viewing peripheral manipulation's influences as a local cause/effect process, the MT literature paints a richer tapestry of centrally mediated impacts. SUMMARY: Evidence from outside the LMT field has introduced a broad tapestry of factors that may contribute to the efficacy of MT, extending beyond the local effects reported in LMT literature. To better understand the effect and mechanism of action touch-based interventions have on a patient's voice and to potentially improve outcomes, it is necessary to broaden investigations to include a broader range of perspectives.

Abnormal Laryngeal Electromyography Findings in Asymptomatic Adults Across the Age Spectrum.

OBJECTIVES/HYPOTHESIS: Laryngeal electromyography (LEMG) is a diagnostic tool for patients with suspected neurogenic abnormalities of the larynx. LEMG is often used with the assumption that any abnormality is symptom-/disease-related. We sought to determine the prevalence of abnormal LEMG findings in a group of healthy asymptomatic adults across a large age spectrum. STUDY DESIGN: Open, prospective study, gender-match and age balanced by decade. METHODS: Forty-six healthy participants (age 20-78) underwent LEMG, including 178 muscles. Participants had no history of voice problems, normal VHI-10, and normal flexible laryngoscopy. Qualitative and quantitative LEMG (bilateral) were performed involving the thyroarytenoid-lateral cricoarytenoid muscle complex (TA-LCA) and cricothyroid (CT) muscles. LEMG parameters included evaluation for fibrillation potentials, sharp waves, reduced recruitment, polyphasic potentials, electrical synkinesis, and measurement of turns per second. RESULTS: Of participants, 4% had at least one abnormal qualitative finding (slightly reduced recruitment or two to three discrete polyphasic potentials). There were no findings of fibrillation potentials or sharp waves. There were no abnormal qualitative findings in the CT muscles tested. Of participants, 16% had at least one abnormal synkinesis finding. LEMG qualitative abnormalities and quantitative abnormalities do not appear to correlate with gender or age. CONCLUSION: Abnormal qualitative and quantitative LEMG findings were uncommon and minor in severity in our group of asymptomatic healthy adults. The likelihood of abnormal LEMG results in asymptomatic adults was 2.2% for qualitative findings, 9.3% for synkinesis, and 5.4% for turns/s. LEVEL OF EVIDENCE: 3 Laryngoscope, 131:2065-2069, 2021.

Crumley's Classification of Laryngeal Synkinesis: A Comparison of Laryngoscopy and Electromyography.

OBJECTIVES/HYPOTHESIS: Applying the principles of misdirected nerve regeneration to the larynx, Roger Crumley in 1989 coined the term laryngeal synkinesis (LS) which he later (2000) classified into 4 types (type I - good voice, type II - involuntary twitches and poor voice, type III - adduction during inspiration, type IV - abduction during phonation). Neurophysiological data were not available for all LS patients at that time. The current study was undertaken to utilize and test the Crumley classification for a clinical interrater comparison and, secondly, compare predicted with actual laryngeal electromyography (LEMG) results. STUDY DESIGN: Descriptive study. METHODS: Laryngoscopic and LEMG data of patients with unilateral vocal fold paralysis (VFP) of 6 months duration or longer were combined for retrospective evaluation. Forty-five data sets were available for laryngoscopic classification by two local laryngologists and by Roger Crumley. Twenty-three data sets with complete thyroarytenoid (TA) and posterior cricoarytenoid (PCA) - EMG data were used to compare predicted with actual LEMG results. RESULTS: Local laryngologists were able to classify 24 of 45, Crumley 30 of 45 cases into one of the 4 synkinesis types. There was substantial agreement between examiners (Cohens Kappa 0.66 [P < .001]). Comparison of predicted and actual LEMG data showed only moderate agreement. EMG sykinesis rates were lower in TA than in PCA and highest in Crumley type I cases. CONCLUSION: The Crumley classification is helpful in describing and understanding synkinesis. It does not always correlate predictably with actual LEMG data. A complete LEMG mapping of all intrinsic muscles may improve understanding of chronic VFP. LEVEL OF EVIDENCE: 4. Laryngoscope, 131:E1605-E1610, 2021.

Laryngeal Electromyography.

Laryngeal electromyography (LEMG) is an important diagnostic and prognostic tool in neurolaryngology. This chapter presents the advances in LEMG in the last 5 years based on clinical trials. LEMG is in most cases an office-based procedure for decision making in neurolaryngology. When performed in a standardized way, LEMG helps to differentiate abnormal function of the vocal folds from nonorganic disorders. It is mainly used to confirm the diagnosis of vocal fold paralysis (VFP) and is less frequently used for the diagnosis of myopathies and motor neuron disorders. Also, the value of LEMG for other diseases than VFP is presented. First consensus recommendations for standard performance of LEMG have been published. This will facilitate the comparison of results from different researchers in the future. For many years, LEMG focused on the thyroarytenoid muscle. Data are presented showing that now more and more studies are performed including other laryngeal muscles, most importantly the posterior cricoarytenoid muscle and cricothyroid muscle. Diagnostics and estimating the prognosis for patients with VFP remains the most important issue for LEMG. First meta-analyses are now available analyzing which LEMG parameters are the best prognosticators for recovery or persistent palsy. Due to the advances in multichannel LEMG, laryngeal nerve monitoring can now control the recurrent laryngeal nerve and the external branch of the superior laryngeal nerve during thyroid surgery. Finally, also the advances of LEMG for laryngeal pacing, guided laryngeal injections, laryngeal electrostimulation, and other indications beyond otolaryngology are discussed.

Long term phonatory function following acoustic neuroma surgery: a cohort study.

Background: Acoustic neuroma (AN) is a well-recognized cause of neurological morbidity, peripheral facial paralysis being one of the most prevalent. Phonatory dysfunction in the late post-operative term has not been properly addressed so far.Objective: The objective of this study is to describe the outcomes of phonatory function on the long-term follow-up of AN surgery and identify its prognostic factors.Material and methods: This cohort study included patients submitted to AN surgery from 1999 to 2014, with a mean follow up of 6.4 ± 4.5 years. To evaluate the phonatory function, we performed a combination of noninvasive acoustic and aerodynamic measurements including vocal intensity and stability, maximum declination rate of the glottal airflow (MDR) and transglottal pressure scale (TP).Results: 101 patients were studied. 25 (24.7%) presented a deficit in phonatory function. Women comprised 56% and the mean age was 42.4 ± 13.8 years (range19-80). 100% presented reduced expiratory airflow capacity with excessive manifestation of the laryngeal musculature (TP > 1,23s ;MDR/z/

The Nerve to Thyrohyoid Muscle as a Novel Donor Nerve for Laryngeal Reinnervation.

OBJECTIVES: Recurrent laryngeal nerve (RLN) injury may be a consequence of surgical procedures of the skull base, neck, and chest, with adverse consequences to function and quality of life. Laryngeal reinnervation offers a potentially stable improvement in vocal fold position and tone. The classic donor nerve is the ansa cervicalis, but is not always available due to damage or sacrifice during previous neck surgeries. Our objective was to introduce the nerve to the thyrohyoid (TH) muscle as an alternate donor nerve for reinnervation, which has not previously been described. METHODS: Case series of two patients using the TH nerve for laryngeal reinnervation after RLN injury, with description of surgical harvest. RESULTS: Follow-up results are available for 10 months (one patient) and 3 years (one patient) demonstrating both subjective and objective improvement in function. GRBAS scores were reduced. Maximal phonation time was improved. Patient rating of voice was stable or improved postoperatively. One patient described significant preoperative dyspnea which was significantly improved postoperatively, from a score of 24 to 10 out of 40 on the dyspnea handicap index. VHI was improved in one patient, but scores elevated in the other, despite a change from "moderately severe impairment" to "normal voice" subjectively. Neither patient experienced significant complications from the procedure. CONCLUSION: Laryngeal reinnervation procedures provide good outcomes in pediatric patients. When ansa cervicalis is not available as a donor nerve, the nerve to TH provides a reasonable alternative.

Bilateral Posterior Cricoarytenoid Myoneurectomy for Abductor Spasmodic Dysphonia.

OBJECTIVE: To discuss the utility and outcomes of bilateral myoneurectomy for treatment of abductor spasmodic dysphonia. METHODS: Bilateral myoneurectomy is a known treatment option for patients with adductor spasmodic dysphonia. Its use for treatment of abductor spasmodic dysphonia, however, has not been documented previously. In this case report, treatment and long-term outcomes of abductor spasmodic dysphonia with bilateral myoneurectomy are discussed. RESULTS: A 50-year-old male presented with abductor spasmodic dysphonia. His initial Voice Handicap Index-10 (VHI-10) score was 29, and he had breathy breaks during 60 series. He had no improvement in vocal quality after 6 botulinum toxin injections over 21 months. He underwent staged bilateral posterior cricoarytenoid partial myoneurectomy, with the left posterior cricoarytenoid myoneurectomy performed 33 months after presentation and right posterior cricoarytenoid myectomy 11 months later. Eight years postoperatively, his VHI-10 score was 12. During postoperative 60 series, the patient demonstrated few breathy breaks. Overall, the patient reports improved quality of life and satisfaction with his voice. CONCLUSION: This is the first report of a long-term follow-up data for bilateral, endoscopic, partial posterior cricoarytenoid muscle myoneurectomy to treat refractory abductor spasmodic dysphonia. Long-term VHI-10 results suggest improvement of symptoms, despite mild difficulty with 60 series. While botulinum toxin therapy is the mainstay of management for abductor spasmodic dysphonia, surgical treatment is a potential alternative at least for refractory cases.

Selective stimulation of human intrinsic laryngeal muscles: Analysis in a mathematical three-dimensional space.

OBJECTIVES/HYPOTHESIS: Standard stimulating methods using square waves do not appropriately restore physiological control of individual intrinsic laryngeal muscles (ILMs). To further explore our earlier study of evoked orderly recruitment by quasitrapezoidal (QT) currents, we integrated the contribution of the cricothyroideus (CT) with attention to mutual activation in an additional patient, based on recent studies of appropriate responses via strict recurrent laryngeal nerve (RLN) stimulation. STUDY DESIGN: Basic science study. METHODS: The patient received functional electrical stimulation (FES) with QT pulses at 5 Hz, 60 to 2,000 µAmp, 100 to 500 µs pulse width, 0 to 500 µs decay. Ipsilateral electromyography (EMG) responses were calculated using the average maximum amplitude, area under the curve, and the root mean square of the rectified amplitude waveforms. The thyroarytenoideus (TA), posterior cricoarytenoideus (PCA), lateral cricothyroideus (LCA), and the CT were each interrogated via two monopolar electrodes, values were recorded in MATLAB, exported to Excel, and analyzed. Individual and mutual recruitment configurations and activation delays with stimulation were explored using multiple regression and exploration factor analyses. RESULTS: A total of 868 EMG data points based on 18 trials and up to 11 subtrials were captured from each of the four ILMs. Various combinations of pulse amplitude, pulse width, and exponential decay were found to produce significant (P ≤ .001) individual ILM responses. CT mirrored the LCA, whereas the TA and PCA exhibited separate interactions along shared trajectories in a three-dimensional space. CONCLUSIONS: FES calibrated to individual and coupled ILMs offers promise for restoring normal and pathological contraction patterns via strict RLN stimulation. LEVEL OF EVIDENCE: 5 Laryngoscope, 130:967-973, 2020.

Vibratory Onset of Adductor Spasmodic Dysphonia and Muscle Tension Dysphonia: A High-Speed Video Study✰.

OBJECTIVE: Adductor spasmodic dysphonia (AdSD) is a challenging voice disorder to diagnose, often erroneously diagnosed as muscle tension dysphonia (MTD) or vocal tremor, due to its similarity in auditory and perceptual presentation. Assessments using laryngoscopy or strobolaryngoscopy procedures have demonstrated limited utility in the diagnosis of spasmodic dysphonia. High-speed videoendoscopy (HSV) provides visualization of the precise vibratory pattern of phonatory onset and thus, offers an alternative to previous diagnostic strategies for visual diagnosis of AdSD. The purpose of this study was to examine vibratory onset of patients with AdSD and patients with MTD using HSV methodology. METHODS: HSV of six adults with AdSD and five adults with MTD were captured during sustained phonation. Digital kymography was used to obtain precise vibrogram data at the mid-membranous region of the vocal fold prior to and at the onset of phonation. Voice onset delay was examined by (1) quantifying timing of prephonatory delay and steady state delay and (2) describing vocal fold onset movements qualitatively in each diagnosis. RESULTS: HSV adequately captured the phonatory onset of the vocal folds. Voice onset delay was not significantly different between AdSD and MTD. However, there were distinct differences in voice onset gestures. Both AdSD and MTD patients presented with vocal hyperfunction during the onset of phonation. In a subset of AdSD patients, a rapid sustained adduction occurred following the initial vibratory motion. Vocal fold vibration then continued until steady phonation was achieved. This oscillatory break pattern was not observed in patients with MTD. Therefore, there appears to be differences in vocal fold vibratory onset motion between MTD and AdSD. CONCLUSION: HSV captures the precise vibratory onset in patients with MTD and AdSD. Differences were most notable after vibratory onset as opposed to vibratory delay measurements. Examination of voice onset gesture may offer an additional laryngeal parameter to assist in the differential diagnosis of spasmodic dysphonia.

A summary of the Clinical Practice Guideline for the Diagnosis and Management of Voice Disorders, 2018 in Japan.

OBJECTIVE: To develop a summary of the first version of the Clinical Practice Guideline of Voice Disorders for Diagnosis, Management, and Treatment in Japan by the Clinical Practice Guideline Committee of the Japan Society of Logopedics and Phoniatrics and The Japan Laryngological Association. The 2018 recommendations, based on a review of the scientific literature, are intended to serve as clinical practice guidelines for the diagnosis, management, and treatment of voice disorders in Japan. METHODS: A summary of the original version of the Clinical Practice Guideline of Voice Disorders for Diagnosis, Management, and Treatment in Japan was described. Recommendations for the diagnosis, management, and treatment of voice disorders were prepared. Twelve clinical questions (CQs) regarding the diagnosis, management, treatment, and effectiveness of therapy for voice disorders were also prepared. RESULTS: A summary of the first version of the clinical practice guidelines for the diagnosis, management, and therapy of voice disorders was prepared and is presented. Additionally, answers to the 12 CQs on the diagnosis, management, treatment, and effectiveness of voice disorder therapy were prepared, and include evidence-based recommendations. CONCLUSION: These guidelines present a summary of the standard approaches for the diagnosis and treatment of voice disorders and relevant CQs that consider the medical environments in Japan. We hope that the guidelines will assist physicians in clinical settings for patients with voice disorders.

Exploring stimulation patterns for electrical stimulation of the larynx using surface electrodes.

PURPOSE: Functional electrical stimulation (FES) is considered an upcoming treatment modality for a number of laryngeal diseases. However, sound data are scarce when it comes to surface FES to treat voice disorders. Aim of the present study was to identify and differentiate suitable surface FES patterns to activate internal laryngeal muscles. METHODS: Non-invasive FES was performed in a cohort of 17 elderly woman. Our user-customized electrical stimulation setup allowed us to deliver ten different stimulation patterns (rectangular and sawtooth shaped) with variation of frequency and amplitude. Stimulation outcome, i.e., vocal fold (VF) reaction, was continuously verified by transnasal endoscopy. RESULTS: Responses to FES using ten different stimulation patterns varied inter-individually. None of the stimulation parameter sets could elicit a VF reaction in all participants. CONCLUSION: Based on our findings we conclude that individual fitting is necessary when defining surface stimulation parameters. To overcome limitations of previous studies, devices with freely programmable patterns are required as shown here. Endoscopic control of VF reaction is absolutely essential to ensure effectiveness of the delivered patterns.

Movement Disorders and Voice.

The primary movement disorders affecting the voice are laryngeal dystonia (including spasmodic dysphonia), essential voice tremor, and Parkinson disease. Diagnosis of these conditions is clinical and based on a detailed history, voice evaluation, and physical and laryngoscopic examination. Laryngeal dystonia and essential voice tremor are hyperfunctional disorders and are treated most commonly with botulinum toxin injections. Parkinson disease is a hypofunctional disorder that may affect the voice and most commonly is treated with Lee Silverman Voice Treatment.

Ultrasonography-guided electromagnetic needle tracking in laryngeal electromyography.

PURPOSE: The clinical evaluation of vocal fold movement disorders should contain the electromyography of the laryngeal muscles (LEMG). The most challenging point in LEMG is the right positioning of the EMG needle in the small target muscles. As the results of the EMG have great influence in the decision of treatment it is important to confirm the results of this examination. Anatomical structures of the larynx should be identified with laryngeal ultrasonography and the ultrasonography (US)-guided electromagnetic needle tracking should guide the LEMG needle to the target muscle. METHODS: The thyroarytenoid (TA) and cricothyroid (CT) muscles had been evaluated in 19 patients (20 examinations). The US-guided transcutaneous LEMG using electromagnetic needle tracking was performed by one ENT doctor and all examinations had been video monitored. The videos were analyzed for the accuracy rate and the visibility of the important laryngeal structures. RESULTS: The laryngeal structures were identified in all the cases using laryngeal ultrasonography. The examination times of the US-guided LEMG were acceptable (8 min, 32 s). The US-guided LEMG was feasible in 56 (36 TA, 20 CT) examinations. The TA and CT could be visualized successfully but in 17 examinations (30%) the signal was not stable. We could still reach the target muscles in more than 50% of these cases. CONCLUSION: US-guided electromagnetic needle tracking in LEMG helps to determine the exact position of the laryngeal structures. With further technical improvement of the stability of the electromagnetic needle tracking signal the US-guided electromagnetic needle tracking of the target muscles in the larynx could help to improve the accuracy of the transcutaneous LEMG.

Asymmetric recurrent laryngeal nerve conduction velocities and dorsal cricoarytenoid muscle electromyographic characteristics in clinically normal horses.

The dorsal cricoarytenoid (DCA) muscles, are a fundamental component of the athletic horse's respiratory system: as the sole abductors of the airways, they maintain the size of the rima glottis which is essential for enabling maximal air intake during intense exercise. Dysfunction of the DCA muscle leads to arytenoid collapse during exercise, resulting in poor performance. An electrodiagnostic study including electromyography of the dorsal cricoarytenoid muscles and conduction velocity testing of the innervating recurrent laryngeal nerves (RLn) was conducted in horses with normal laryngeal function. We detected reduced nerve conduction velocity of the left RLn, compared to the right, and pathologic spontaneous activity (PSA) of myoelectrical activity within the left DCA muscle in half of this horse population and the horses with the slowest nerve conduction velocities. The findings in this group of horses are consistent with left sided demyelination and axonal loss, consistent with Recurrent Laryngeal Neuropathy (RLN), a highly prevalent degenerative disorder of the RLn in horses that predominantly affects the left side. The detection of electromyographic changes compatible with RLN in clinically unaffected horses is consistent with previous studies that identified "subclinical" subjects, presenting normal laryngeal function despite neuropathologic changes within nerve and muscle confirmed histologically.

Selective reinnervation using phrenic nerve and hypoglossal nerve for bilateral vocal fold paralysis.

OBJECTIVE: To evaluate the extent of airway improvement and voice quality in patients with bilateral vocal fold paralysis (BVFP) who underwent selective laryngeal reinnervation surgery. METHODS: Seven patients with BVFP caused by thyroid surgeries were enrolled. They underwent selective laryngeal reinnervation surgery. Videostroboscopy data, voice perceptual data (grade [G]), acoustic data, laryngeal electromyography data, and pulmonary function test data were obtained preoperatively and postoperatively. RESULTS: Videostroboscopic videos showed that six patients could achieve moderate-to-maximal abduction in the bilateral vocal folds during inspiration, whereas all patients achieved adduction in the bilateral vocal folds during phonation at 4 to 7 months postoperatively. G score was decreased significantly versus preoperative values (P < 0.05), and vocal functional parameters were improved significantly at 12 months postoperatively (P < 0.05). The aerodynamic parameter of maximum phonation time was significantly longer than the preoperative value (P < 0.05). Most parameters in pulmonary function test recovered to normal reference levels as early as 3 months postoperatively, whereas maximal inspiratory pressure (PImax) values were still slightly lower than normal levels 12 months after surgery. All of these parameters improved significantly versus preoperative values. Electromyographic data at 12 months postoperatively showed full interference potentials in bilateral posterior cricoarytenoid muscles during inspiration and full interference potentials in bilateral thyroarytenoid muscles during phonation in all patients. Moderate electric potentials were seen in left interarytenoid muscle in one failed patient. CONCLUSION: This new selective laryngeal reinnervation procedure can achieve physiological movements of the bilateral vocal folds in selected patients with BVFP. LEVEL OF EVIDENCE: 4. Laryngoscope, 129:2669-2673, 2019.

Pediatric laryngeal electromyography technique for vocal fold immobility using bipolar double hookwire electrodes.

Vocal fold immobility (VFI) is a common cause of dysphonia and dysphagia in children. Laryngeal electromyography (LEMG) is an important adjunctive test in its diagnosis and treatment. In this study, we present an alternative technique in which bipolar double hookwire electrodes allow simultaneous placement and recordings from the bilateral thyroarytenoid and posterior cricoarytenoid muscles. Details of the technique are shown for a 5 y/o F with history of Neurofibromatosis Type 2 with left VFI and aspiration and dysphonia. This modified technique for pediatric LEMG has the potential to be a useful tool in predicting return of laryngeal function.