Long-term stimulation by implanted pacemaker enables non-atrophic treatment of bilateral vocal fold paresis in a human-like animal model.

A wide variety of treatments have been developed to improve respiratory function and quality of life in patients with bilateral vocal fold paresis (BVFP). One experimental method is the electrical activation of the posterior cricoarytenoid (PCA) muscle with a laryngeal pacemaker (LP) to open the vocal folds. We used an ovine (sheep) model of unilateral VFP to study the long-term effects of functional electrical stimulation on the PCA muscles. The left recurrent laryngeal nerve was cryo-damaged in all animals and an LP was implanted except for the controls. After a reinnervation phase of six months, animals were pooled into groups that received either no treatment, implantation of an LP only, or implantation of an LP and six months of stimulation with different duty cycles. Automated image analysis of fluorescently stained PCA cross-sections was performed to assess relevant muscle characteristics. We observed a fast-to-slow fibre type shift in response to nerve damage and stimulation, but no complete conversion to a slow-twitch-muscle. Fibre size, proportion of hybrid fibres, and intramuscular collagen content were not substantially altered by the stimulation. These results demonstrate that 30 Hz burst stimulation with duty cycles of 40% and 70% did not induce PCA atrophy or fibrosis. Thus, long-term stimulation with an LP is a promising approach for treating BVFP in humans without compromising muscle conditions.

Impact of functional electrical stimulation on nerve-damaged muscles by quantifying fat infiltration using deep learning.

Quantitative imaging in life sciences has evolved into a powerful approach combining advanced microscopy acquisition and automated analysis of image data. The focus of the present study is on the imaging-based evaluation of the posterior cricoarytenoid muscle (PCA) influenced by long-term functional electrical stimulation (FES), which may assist the inspiration of patients with bilateral vocal fold paresis. To this end, muscle cross-sections of the PCA of sheep were examined by quantitative image analysis. Previous investigations of the muscle fibers and the collagen amount have not revealed signs of atrophy and fibrosis due to FES by a laryngeal pacemaker. It was therefore hypothesized that regardless of the stimulation parameters the fat in the muscle cross-sections would not be significantly altered. We here extending our previous investigations using quantitative imaging of intramuscular fat in cross-sections. In order to perform this analysis both reliably and faster than a qualitative evaluation and time-consuming manual annotation, the selection of the automated method was of crucial importance. To this end, our recently established deep neural network IMFSegNet, which provides more accurate results compared to standard machine learning approaches, was applied to more than 300 H&E stained muscle cross-sections from 22 sheep. It was found that there were no significant differences in the amount of intramuscular fat between the PCA with and without long-term FES, nor were any significant differences found between the low and high duty cycle stimulated groups. This study on a human-like animal model not only confirms the hypothesis that FES with the selected parameters has no negative impact on the PCA, but also demonstrates that objective and automated deep learning-based quantitative imaging is a powerful tool for such a challenging analysis.

[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.

Understanding the variability of the electrophysiologic laryngeal adductor reflex.

OBJECTIVE: The laryngeal adductor reflex (LAR) is vital for airway protection and can be electrophysiologically obtained under intravenous general anesthesia (IGA). This makes the electrophysiologic LAR (eLAR) an important tool for monitoring of the vagus nerves and relevant brainstem circuitry during high-risk surgeries. We investigated the intra-class variability of normal and expected abnormal eLAR. METHODS: Repeated measures of contralateral R1 (cR1) were performed under IGA in 58 patients. Data on presence/absence of cR2 and potential confounders were also collected. Review of neuroimaging, pathology and clinical exam, allowed classification into normal and expected abnormal eLAR groups. Using univariate and multivariate analysis we studied the variability of cR1 parameters and their differences between the two groups. RESULTS: In both groups, cR1 latencies had coefficients of variation of <2%. In the abnormal group, cR1 had longer latencies, required higher activation currents and was more frequently desynchronized and unsustained; cR2 was more frequently absent. CONCLUSIONS: cR1 latencies show high analytical precision for measurements. Delayed onset, difficult to elicit, desynchronized and unsustained cR1, and absence of cR2 signal an abnormal eLAR. SIGNIFICANCE: Understanding the variability and behavior of normal and abnormal eLAR under IGA can aid in the interpretation of its changes during monitoring.

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.

Electromyographic measures of asymmetric muscle control of swallowing in Parkinson's disease.

INTRODUCTION: During the early stages, Parkinson's disease (PD) is well recognized as an asymmetric disease with unilateral onset of resting tremor with varying degrees of rigidity, and bradykinesia. However, it remains unknown if other impairments, such as swallowing impairment (i.e., dysphagia), also present asymmetrically. PURPOSE: The primary aim of this study was to examine muscle activity associated with swallow on the most affected side (MAS) and least affected side (LAS) in persons with PD. A secondary aim was to explore the relationship between differences in muscle activity associated with swallow and subjective reports of swallowing impairment and disease severity. METHODS: Function of muscles associated with swallowing was assessed using surface electromyography placed over the right and left submental and laryngeal regions during three swallows for a THIN and THICK condition. The Swallowing Quality of Life (SWAL-QOL) questionnaire and the Unified Parkinson's Disease Rating Scale (UPDRS) were collected as measures of subjective swallow impairment and disease severity, respectively. RESULTS: Thirty-five participants diagnosed with idiopathic PD and on a stable antiparkinsonian medication regimen completed this study. Results revealed no significant mean difference in muscle activity during swallow between the more and less affected side. For the laryngeal muscle region, a significant difference in coefficient of variation between the MAS and LAS was revealed for peak amplitude for the THIN swallow condition. For the laryngeal muscle region, a significant association was revealed between muscle activity and disease severity but not subjective reports of swallowing impairment. CONCLUSION: Superficially it appears that swallowing impairment present symmetrical during the early stages of PD, however, our variability data indicates otherwise. These results will be used to inform future studies in specific types of swallowing impairment (i.e., oral dysphagia, pharyngeal dysphagia, and esophageal dysphagia), disease progression, and overall asymmetry.

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.

Quantitative laryngeal electromyography parameters may correlate with improved outcomes following botulinum toxin injection for spasmodic dysphonia.

BACKGROUND: Despite use of qualitative laryngeal electromyography (LEMG) guided botulinum toxin A (BoNT-A) injection for treatment of adductor spasmodic dysphonia (AdSD), unsatisfactory injections and complete "misses" remain problematic. We aimed to determine if the quantitative LEMG measure of number of small segments (NSS) correlates with voice outcomes following (BoNT-A injection for AdSD. METHODS: Automated quantitative LEMG analysis was performed during electromyography (EMG) -guided BoNT-A injection into the thyroarytenoid-lateral cricoarytenoid muscle complex for treatment of AdSD. Pre-injection phonatory NSS values were correlated with clinical voice outcomes and patient reported injection results. RESULTS: Quantitative LEMG measures were obtained for 45 AdSD patients (28 female, mean age 60.8 ± 12.8 years) during EMG-guided BoNT-A injection. Mean sampled NSS during phonation immediately prior to BoNT-A injection was 524 ± 323 (range: 2-904). Mean follow up was 36.5 ± 9.4 days; one patient was lost to follow-up. In comparison to their previous BoNT-A injection, the current injection was rated as worse, same, and better by 13 (29.5%), 25 (56.8%), and 6 (13.6%) patients, respectively. All 4 (9.1%) patients with NSS < 200 rated their BoNT-A injection result as worse than previous, and change in Voice Handicap Index-10 (VHI-10) scores were worse or without change. CONCLUSIONS: Aiming for an NSS value greater than 200 during phonation prior to BoNT-A toxin injection for AdSD may reduce unfavorable voice outcomes.

Muscle Tension Dysphagia: Contributing Factors and Treatment Efficacy.

OBJECTIVE: To determine factors contributing to disease etiology and treatment efficacy. STUDY DESIGN: Original Report. SETTING: Tertiary academic center. METHODS: IRB approved prospective study of 20 patients with reported dysphagia who exhibited normal oropharyngeal and esophageal swallowing function as evidenced by videofluoroscopic swallow study, esophagogastroduodenoscopy, high-resolution esophageal manometry with stationary impedance, and Bravo pH probe off proton pump inhibitor. Patients underwent speech-language pathology intervention. RESULTS: Atypical laryngeal muscle tension was present in 100% of patients. Forty percent of patients had diagnosed positive gastroesophageal reflux disease. Sixty-five percent of patients showed signs of non-specific laryngeal inflammation and laryngeal hyperresponsiveness during strobolaryngoscopy. All patients reported a mean of 90% recovery by the completion of voice therapy directed toward unloading muscle tension. CONCLUSION: The study results suggest an association between laryngeal muscle tension and these patients' dysphagia symptoms regardless of associated conditions. Speech-language pathology intervention showed high treatment efficacy. LEVEL OF EVIDENCE: 2c- Outcomes research.

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.

Visual Neurolaryngology.

Visual diagnosis of laryngeal neurologic impairments is not only possible but is perhaps the most accurate method for evaluating the neurologic status of the upper airway. Precise assessments may lead to appropriate treatment without an EMG study. Principles of the neurolaryngology examination include: (1) each muscle has a single action; (2) that action can be elicited and to some degree isolated and visualized; (3) each muscle has an appropriate time to contract; (4) that timing can be compared to the opposite side; (5) inappropriate timing represents reinnervation; (6) inappropriate degree of motion represents reinnervation; (7) patients naturally compensate for any loss; (8) removing compensation during an exam reveals pathology. Some of the visual diagnostic findings available to the astute endoscopic examiner are (1) paralysis, (2) paresis, (3) synkinesis, (4) fixation, (5) tremor, (6) spasm, and (7) reinnervation.

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.

Muscle activity and kinematics show different responses to recurrent laryngeal nerve lesion in mammal swallowing.

Understanding the interactions between neural and musculoskeletal systems is key to identifying mechanisms of functional failure. Mammalian swallowing is a complex, poorly understood motor process. Lesion of the recurrent laryngeal nerve, a sensory and motor nerve of the upper airway, results in airway protection failure (liquid entry into the airway) during swallowing through an unknown mechanism. We examined how muscle and kinematic changes after recurrent laryngeal nerve lesion relate to airway protection in eight infant pigs. We tested two hypotheses: 1) kinematics and muscle function will both change in response to lesion in swallows with and without airway protection failure, and 2) differences in both kinematics and muscle function will predict whether airway protection failure occurs in lesion and intact pigs. We recorded swallowing with high-speed videofluoroscopy and simultaneous electromyography of oropharyngeal muscles pre- and postrecurrent laryngeal nerve lesion. Lesion changed the relationship between airway protection and timing of tongue and hyoid movements. Changes in onset and duration of hyolaryngeal muscles postlesion were less associated with airway protection outcomes. The tongue and hyoid kinematics all predicted airway protection outcomes differently pre- and postlesion. Onset and duration of activity in only one infrahyoid and one suprahyoid muscle showed a change in predictive relationship pre- and postlesion. Kinematics of the tongue and hyoid more directly reflect changes in airway protections pre- and postlesion than muscle activation patterns. Identifying mechanisms of airway protection failure requires specific functional hypotheses that link neural motor outputs to muscle activation to specific movements.NEW & NOTEWORTHY Kinematic and muscle activity patterns of oropharyngeal structures used in swallowing show different patterns of response to lesion of the recurrent laryngeal nerve. Understanding how muscles act on structures to produce behavior is necessary to understand neural control.

Laryngeal electromyography in amyotrophic lateral sclerosis.

BACKGROUND: Bulbar involvement is a hallmark of amyotrophic lateral sclerosis (ALS), but surprisingly very few studies have addressed the frequency, pattern and clinical relevance of laryngeal involvement in the disease. METHODS: Twenty-six patients with spinal-onset ALS underwent nasofibroscopy (NF), followed by laryngeal electromyography (LEMG). We also studied resting activity and motor unit potentials of the genioglossus and masseter muscles. RESULTS: Twenty-four patients presented neurogenic changes in at least one laryngeal muscle. There were fibrillation and/or fasciculation potentials associated with chronic neurogenic changes in the same muscle in 16 patients; of these, 9 had no alteration in the genioglossus. We found no patient with tongue neurogenic changes and normal LEMG. NF was abnormal in 14 patients; in the remaining 12, LEMG identified neurogenic changes in 11 of them. CONCLUSION: LEMG is able to identify laryngeal denervation in patients with ALS, sometimes before clinical manifestations are noticed. This technique may be a useful diagnostic tool for selected patients with suspicion of ALS.

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/

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.

Detection of Muscle Tension Dysphonia Using Eulerian Video Magnification: A Pilot Study.

OBJECTIVE: To determine whether Eulerian Video Magnification software is useful in diagnosis of muscle tension dysphonia (MTD). STUDY DESIGN: Prospective. METHODS: Adult patients scheduled in a tertiary care laryngology practice for evaluation of dysphonia were recruited between November 2016 and March 2017. Demographic and clinical data were extracted from patient charts. Diagnosis of MTD was confirmed with videostroboscopic and physical exam and by a speech-language pathologist. Eighteen MTD patients were video recorded while at rest and with phonation. Five patients without MTD also were analyzed as controls. Videos were analyzed using Eulerian Video Magnification software (Massachusetts Institute of Technology) to assess change in blood flow at the forehead, infrahyoid muscles, and sternocleidomastoid muscles, while using the values of the background wall as a control value. RESULTS: Patients with MTD demonstrated little change in perfusion to the infrahyoid muscles of the neck while phonating (+1% ± 55%). Control subjects demonstrated an increase in perfusion to the infrahyoid muscles while phonating (+102% ± 164%), with this change being significant when comparing the two groups (P = 0.04, t = 2.189, df = 21). A change in perfusion of 0% or less to infrahyoid muscles was 75% sensitive and 70% specific for diagnosis of MTD. No differences in perfusion were found between other regions assessed. Patient age and gender did not correlate with any change in perfusion between rest and phonation. CONCLUSION: Our data suggest that Eulerian Video Magnification can be used in the diagnosis of MTD by focusing on the difference in perfusion to the infrahyoid muscles between rest and phonation.

The impact of cricothyroid involvement on adductor recovery in unilateral vocal fold paralysis.

OBJECTIVES/HYPOTHESIS: Wide variation in postinjury functional recovery is a hallmark of unilateral vocal fold paralysis (UVFP), ranging from zero to full recovery. The present study examined the impact of cricothyroid (CT) muscle involvement on recovery using quantitative laryngeal electromyography (LEMG) of the thyroarytenoid-lateral cricoarytenoid (TA-LCA) muscle complex at multiple times postinjury. STUDY DESIGN: Prospective cohort study in a medical center. METHODS: Eighty-one patients with UVFP (37 males and 44 females) received an initial assessment of quantitative LEMG, stroboscope, acoustic voice analysis and 36-Item Short Form Survey quality-of-life questionnaire at 3 to 6 months after UVFP onset and a follow-up assessment at 12 months after UVFP onset. RESULTS: The initial and follow-up assessments were performed at 4.3 ± 1.9 and 12.5 ± 1.3 months after UVFP onset, respectively. The peak turn frequency of the TA-LCA muscle complex on the lesion side was improved at the follow-up (470 ± 294 Hz) compared with the initial assessment (300 ± 204 Hz) (P < .001). Patients were also divided into two groups with (n = 27) and without (n = 54) CT involvement, respectively. TA-LCA muscle complex turn frequency improved in patients without CT involvement (from 277 ± 198 to 511 ± 301 Hz; P < .001), but not in those with CT involvement (from 345 ± 211 to 386 ± 265 Hz; P = .46). Seventy-one of all patients received early intervention with intracordal hyaluronate injection, showing similar therapeutic effects in those with and without CT involvement. CONCLUSIONS: Acute UVFP with combined TA-LCA muscle complex and CT muscle involvement has a poor prognosis, with poorer recovery of TA-LCA muscle complex recruitment. Early interventions should be considered in patients with UVFP with CT involvement. LEVEL OF EVIDENCE: 2 Laryngoscope, 130:139-145, 2020.