Laryngeal Electromyography Research Articles

Technical Challenges for Laryngeal Electromyography.

Laryngeal electromyography (LEMG) is a useful diagnostic test in the evaluation of vocal fold paralysis (VFP). This study investigates factors that can make LEMG challenging to perform. Patients with subacute unilateral VFP presented for LEMG were prospectively enrolled. Demographic data including BMI, previous neck surgery, and anatomic factors were collected. Patient-reported pain related to the procedure was recorded on a visual analogue scale (VAS). Electromyographer and otolaryngologist recorded a consensus rating of the perceived difficulty in performing the test and confidence in using the results for clinical decision-making. A total of 111 patients (56.8% female) were enrolled between August 2015 and August 2018. The mean age was 55 ± 14 years, and the average body mass index (BMI) was 28.5 ± 6.4. The mean patient-reported VAS score for pain was 35 ± 24. Notably, 31.2% of the tests were considered "very easy," 32.1% were considered "mildly challenging" and 23.9% and 12.8% were considered "moderately challenging" and "extremely challenging," respectively, by the clinicians. Common factors affecting LEMG difficulty included poorly palpable surface anatomy (50.5%) and patient intolerance (15.6%). Clinicians felt confident in 76.1% of the test findings. Bivariate analyses showed that prior neck surgery is associated with elevated VAS (p = 0.02), but clinician-perceived difficulty of performing the test is not associated with elevated VAS scores (p = 0.55). Majority of LEMG tests are well tolerated by patients. Physicians reported more confidence using LEMG for clinical decision-making when the test was easier to perform. Difficult surface anatomy and patient intolerance affects clinician confidence in integrating the test results with clinical care. 3 Laryngoscope, 134:831-834, 2024.

Training for Awake, Office-Based Laryngeal Procedures-The Laryngology Fellow's Perspective.

The aim was to explore recent laryngology graduates' perspectives on their experience, competency, and challenges learning office-based procedures during fellowship training in the United States and Canada. Anonymous 22-item questionnaire survey was distributed electronically to fellowship-trained laryngologists having completed fellowship within past 5 years. Ninety fellowship-trained laryngologists between 2018 and 2022 were surveyed. Response rate was 48.9% (n = 44), 1 declined participation, with 20 different fellowship programs represented. Fellows were frequently provided the opportunity to act as primary surgeon for most procedures, except for laryngeal botulinum toxin injection, diagnostic laryngeal electromyography, trans-nasal esophagoscopy, secondary tracheoesophageal puncture, and high-resolution pharyngeal manometry. A majority reported high (n = 27, 62.8%) or moderate (n = 12, 27.9%) confidence with vocal fold injection augmentation. Various techniques were taught: transoral (74.4%), cricothyroid (74.4%), thyrohyoid (69.8%), transcartilagenous (14.0%), and catheter-needle (25.6%). Numerous statistically significant associations with independent procedure involvement and competence were identified. Laryngeal botulinum toxin injection was a procedure performed with high frequency but low volume of independent fellow involvement, and the procedure with which fellows reported wanting more practice learning. Most common training barriers included patient being awake, patient consenting to trainee performing the procedure, and the technical challenge/complexity of the procedure. Teaching methods/tools largely focused on informal debriefing (97.3%) and case by case troubleshooting (81.1%). Laryngology fellows are well trained with favorable perceived levels of competence for numerous office-based procedures, particularly vocal fold injection augmentation. Procedures for which fellows reported a low level of independent participation trended towards lower perceived competency. 5 Laryngoscope, 134:873-881, 2024.

Early Changes in Porcine Larynges Following Injection of Motor-Endplate Expressing Muscle Cells for the Treatment of Unilateral Vocal Fold Paralysis.

No curative injectable therapy exists for unilateral vocal fold paralysis. Herein, we explore the early implications of muscle-derived motor-endplate expressing cells (MEEs) for injectable vocal fold medialization after recurrent laryngeal nerve (RLN) injury. Yucatan minipigs underwent right RLN transection (without repair) and muscle biopsies. Autologous muscle progenitor cells were isolated, cultured, differentiated, and induced to form MEEs. Three weeks after the injury, MEEs or saline were injected into the paralyzed right vocal fold. Outcomes including evoked laryngeal electromyography (LEMG), laryngeal adductor pressure, and acoustic vocalization data were analyzed up to 7 weeks post-injury. Harvested porcine larynges were examined for volume, gene expression, and histology. MEE injections were tolerated well, with all pigs demonstrating continued weight gain. Blinded analysis of videolaryngoscopy post-injection revealed infraglottic fullness, and no inflammatory changes. Four weeks after injection, LEMG revealed on average higher right distal RLN activity retention in MEE pigs. MEE-injected pigs on average had vocalization durations, frequencies, and intensities higher than saline pigs. Post-mortem, the MEE-injected larynges revealed statistically greater volume on quantitative 3D ultrasound, and statistically increased expression of neurotrophic factors (BDNF, NGF, NTF3, NTF4, NTN1) on quantitative PCR. Minimally invasive MEE injection appears to establish an early molecular and microenvironmental framework to encourage innate RLN regeneration. Longer follow-up is needed to determine if early findings will translate into functional contraction. NA Laryngoscope, 134:272-282, 2024.

Clinical Experiences of Speech-Language Pathologists in the Rehabilitation of Unilateral Vocal Fold Paralysis

Unilateral vocal fold paralysis (UVFP) is a neurological voice disorder that is often first treated by a speech-language pathologist (SLP). In literature, little consensus is found regarding voice therapy onset, duration, frequency, and content. The aim of the current study is to investigate the clinical practice of SLPs for treatment of UVFP regarding diagnostics and treatment characteristics. Additionally, the study examined the personal experiences of SLPs regarding UVFP care. An online survey was completed by 37 respondents, all SLPs with experience in treating UVFP. Demographic characteristics, experiences with voice assessments and treatment modalities were examined. Lastly, experiences and opinions of SLPs on evidence-based practice and their own clinical practice were surveyed. Almost all respondents used a multidimensional voice assessment with findings from laryngovideostroboscopy to assess UVFP. Laryngeal electromyography is not yet integrated in regular clinical practices. The most commonly used vocal techniques were resonant voice exercises, laryngeal manipulation, semioccluded vocal tract exercises (SOVTEs), vocal hygiene, and Vocal Function Exercises, with SOVTEs most often considered effective. A total of 75% of the respondents feel confident treating UVFP, and 87.6% believe it is important to stay updated on evidence-based practice. Variation in therapy timing and dosage was observed, and 48.4% of SLPs usually started early voice therapy within 4 weeks after UVFP onset. Flemish SLPs generally feel confident treating UVFP patients and show interest in improving evidence-based practice. Initiatives to train clinicians further in UVFP care and encouraging SLPs to provide practice-based evidence will enhance the knowledge base for evidence-based practice in UFVP.

The Relationship Between Vocal Fold Mobility Disorders and Ineffective Esophageal Motility

Deglutition, speech production, and airway protection are extraordinarily complex, interrelated functions that are coordinated, in large part, by the motor and sensory innervation of CN X. Previous studies assessing the relationship between neurogenic voice disorders and dysphagia have focused on the risk of aspiration due to glottic insufficiency and the association of vocal fold hypomobility (VFH) with systemic neurologic disease. The purpose of this study was to investigate the relationship between VFH disorders and ineffective esophageal motility (IEM). Adult voice patients who underwent laryngeal electromyography (LEMG) and dual 24-hour pH impedance with high-resolution manometry (HRM) testing were included in the study. Subjects were assigned to one of two groups based on the presence or absence of moderate-to-severe RLN and/or SLN VFH (Mo-SLNH/RLNH) using results from six muscle LEMG tests. In subjects with Mo-SLNH/RLNH, there was 0-60% muscle recruitment on LEMG, whereas control subjects in the non-Mo-SLNH/RLNH group demonstrated 61-100% muscle recruitment. Analysis of mild-to-severe VFH (80% muscle recruitment or less) was also performed in a similar manner. The prevalence of IEM, defined using Chicago Classification Version 4.0 (CCv4.0), was compared between groups, as were HRM parameters. One hundred sixty-two subjects were included (37.7% male/62.3% female, mean age of 43.88 ± 17.285). No differences in IEM prevalence were found when stratifying for cases of mild-to-severe VFH. However, there was significantly higher percentage of IEM in those with Mo-SLNH/RLNH. Mo-SLNH/RLNH subjects demonstrated higher rates of weak swallows and inefficient swallows, as well as lower IBP and UES residual pressures on HRM. Patients with Mo-SLNH/RLNH demonstrated a significantly higher prevalence of IEM. Those with mild-to-severe VFH did not. Higher rates of ineffective and weak swallows, and lower IBP and UES residual pressures among Mo-SLNH/RLNH subjects suggest a possible connection between Mo-SLNH/RLNH and IEM disorders. These manometric differences were more prominent with sub-stratification of the Mo-SLNH/RLNH group by IEM. Additional research is advised.

Thyroarytenoid Muscle Avulsion

Thyroarytenoid muscle avulsion is a rare condition in which laryngeal trauma causes a separation of the thyroarytenoid muscle from the arytenoid cartilage. Typically, symptoms are nonspecific but include severe dysphonia and voice fatigue. They are similar to symptoms of vocal process avulsion. Strobovideolaryngoscopy, laryngeal electromyography, and laryngeal computed tomography may be helpful in diagnosis. However, intraoperative palpation under general anesthesia is the most definitive way to establish its diagnosis. We present two cases of thyroarytenoid muscle avulsion, a condition that has not been described previously. Surgical techniques for repair are detailed.

Assessing the Prevalence and Associated Risk Factors for Presbylarynx in the Elderly Laryngology Population

The primary objective of this study was to assess the prevalence of presbylarynx and its associated features in an elderly population representative of patients seen in a tertiary care laryngology practice. The secondary objective of this study was to compare laryngeal electromyography (LEMG) findings, coexisting VF conditions, medical history, surgical history, medication use, and other parameters between patients with and without presbylarynx. Adult voice patients aged 60 years and older who underwent strobovideolaryngoscopy were included in the study. Patients were assigned to one of two groups based on the majority (≥2/3) agreement of three blinded authors' (GA, KL, and HP) graded examinations of strobovideolaryngoscopy (SVL) videos for findings consistent with presbylarynx (atrophic vocal folds [VFA], vocal fold bowing [VFB], vocal process prominence [VPP] and anterior glottic insufficiency [GI]). Patient demographics, medical history, surgical history, medication use, laboratory results, and SVL videos were compiled. Statistical analysis was performed using SPSS 28.0.0.0 (IBM, Armonk, NY). All tests were performed two-tailed, and a P-value of less than 0.05 was considered statistically significant. One hundred sixty-four patients (84 female/80 male, mean age of 68.397 ± 4.947 years) were included in this study. The prevalence of presbylarynx was 52.4% (n=86) in the study population. The mean age of patients in the presbylarynx group was significantly higher than the nonpresbylarynx group. Additionally, there were significantly more males than females in the presbylarynx group. The presbylarynx group also was found to have a higher proportion of ACE inhibitor (ACEi) use. Further, laboratory results revealed a significantly higher proportion of patients with elevated thyroid stimulating hormone (TSH) levels in the presbylarynx group. Conversely, patients in the nonpresbylarynx group were found to have a significantly higher rate of levothyroxine use. On SVL, patients in the nonpresbylarynx cohort were found to have a significantly higher proportion of benign vocal fold lesions and vocal fold paresis. However, LEMG testing revealed no statistically significant differences in muscle recruitment between groups. Men with presbylarynx were found to have a significantly higher proportion of VFB and VPP compared to women with presbylarynx. This retrospective study investigated the prevalence and risk factors associated with presbylarynx in patients representative of those treated by laryngologists. Signs consistent with presbylarynx are observable even in the presence of coexisting VF conditions. Older age, elevated TSH, the use of ACEi, and male gender was associated with signs of presbylarynx on SVL. Of those diagnosed with presbylarynx, males were identified as having higher proportions of VFB and VPP compared to females. More education regarding presbylarynx and further studies to improve standardization of the criteria for its diagnosis, as well as its relationship with other VF conditions, are encouraged to improve management of the aging voice.

Laryngeal sensory neuropathy caused by COVID-19: findings using laryngeal electromyography

PurposeLaryngeal sensory neuropathy (LSN) is caused by a disorder of the superior laryngeal nerve or the recurrent laryngeal nerve. A diagnosis of LSN should include laryngeal electromyography (LEMG) and laryngovideostroboscopy (LVS). The aim of this study was to characterize the physical and subjective symptoms of neuropathy in patients diagnosed with LSN following COVID-19.Material and methodsSince the beginning of the COVID-19 pandemic, 6 patients who had recovered from the disease presented to us with LSN symptoms. All patients underwent laryngological and phoniatric examination, objective and subjective voice assessment, and LEMG.ResultsThe most common LSN symptom reported by patients was periodic hoarseness of varying severity. Other common symptoms were the sensation of a foreign body in the throat and voice fatigue. Endoscopy often showed functional abnormalities. The LSN patients could be characterized by LEMG recordings, and all showed abnormal activity of the cricothyroid (CT) muscle. The degree of EMG changes in the CT correlated moderately with the severity of dysphonia.ConclusionsSensory neuropathy of the larynx may be a long-lasting complication of SARS-COV-2 infection. The severity of EMG neuropathic changes in the CT muscle broadly corresponds to the severity of dysphonia.

3D VOSNet: Segmentation of endoscopic images of the larynx with subsequent generation of indicators

Video laryngoscope is available for visualizing the motion of vocal cords and aid in the assessment of analyzing the larynx-related lesion preliminarily. Laryngeal Electromyography (EMG) needs to be performed to diagnose the factors of vocal cord paralysis, which may cause patient feeling unwell. Thus, the problem is the lack of credible larynx indicators to evaluate larynx-related diseases in the department of otolaryngology. Therefore, this paper aims to propose a 3D VOSNet model, which has the characteristics of sequence segmentation to extract the time-series features in the video laryngoscope. The 3D VOSNet model can keep the time-series features of three images before and after of the specific image to achieve translation and occlusion invariance, which explicitly signifies that our model can segment and classify each item in the video of laryngoscopy not affected by extrinsic causes such as shaking or occlusion during laryngoscope. Numerical results revealed that the testing accuracy rates of the glottal, right vocal cord, and the left vocal cord are 89.91%, 94.63%, and 93.48%, respectively. Our proposed model can segment glottal and vocal cords from the sequence of laryngoscopy. Finally, using the proposed algorithm computes six larynx indicators, which are the area of the glottal, area of vocal cords, length of vocal cords, deviation of length of vocal cords, and symmetry of the vocal cords. In order to assist otolaryngologists in staying credible and objective when making decisions without any doubt during diagnosis and also explaining the clinical symptoms of the larynx such as vocal cord paralysis to patients after diagnosis, our proposed algorithm provides otolaryngologists with explainable indicators (X-indicators).

Ultrasound-guided injection into the lateral crico-arytenoid muscle: a pilot study

ObjectivesThe anterior, percutaneous Botulinum neurotoxin (BoNT) injection in the lateral cricoarytenoid muscle (LCA) guided by laryngeal electromyography (LEMG) is considered the golden standard treatment for several neurolaryngological disorders. The study presented in this article aims to assess the effectiveness of an alternative approach by which the injection is performed laterally under ultrasound monitoring.Study designAnatomical dissection study in human cadavers.SettingsAcademic health care center.MethodsUltrasound-guided bilateral dye (0.1 mL of dye solution containing cold-curing polymers, latex, acrylates, acrylic esters, alcohol, and green color) injection in the LCA was performed by means of 24G needles and 1 mL syringes using the lateral approach. The dye location and distribution were assessed by anatomic dissection, performed immediately after the injection.ResultsIn 9/10 specimens, the dye was exclusively detectable in the LCA. In 1/10 case (left side), the dye could not be delivered in the LCA because of unintended penetration of the thyroid cartilage by the needle during injection. Anatomic dissection confirmed that the dye spread neither into the thyroarytenoid (TA) nor the cricothyroid muscle (CT).ConclusionsThe anatomic dissection following lateral dye injection in the LCA under ultrasound guide confirmed the precision of this approach in delivery a substance exclusively in a pre-determined target. This feature makes this method an interesting addition or alternative to the standard LEMG-guided BoNT injection at least when the LCA is its target.Level of evidenceIII.

Does the Severity of Vocal Fold Paresis on Laryngeal Electromyography Correlate With Radiographic Findings on Cross Sectional Imaging?

Unilateral vocal fold paresis or paralysis (UVFP) is a condition for which radiographic evaluation and laryngeal electromyography (LEMG) are valuable to evaluate severity of injury and direct treatment plans. Despite extensive research involving findings suggestive of UVFP with radiographic imaging, no study has attempted to determine which findings suggestive of UVFP on imaging are clinically significant and suggest a need for intervention. The purpose of this study was to evaluate whether the severity of vocal fold paresis/paralysis affects the likelihood of encountering radiographic findings suggestive of UVFP. We also aimed to determine which findings suggestive of UVFP on imaging were clinically significant and were associated with surgical intervention. A retrospective chart review was conducted of patients who had been diagnosed with unilateral vocal fold paresis or paralysis and had been evaluated by CT scan and/or magnetic resonance imaging and laryngeal electromyography (EMG) between the dates of January 1, 2017 and January 9, 2018. Fisher's exact testing with Monte Carlo Simulation was utilized to determine statistical significance of identified relationships.Univariate analysis was conducted to assess for individual relationships between imaging results and the potential predictor variables. Chi square analysis was conducted with the various categorical variables to assess for any potential relationships to imaging results. Statistical significance was determined utilizing chi square analysis. After data collection, 130 patients were included in the study population. Of the 112 patients with documented MRI results, 17% had a reported imaging abnormality suggestive of true vocal fold paresis or paralysis (VFP). Of the 71 patients with documented CT Neck results, 15.4% had an abnormality potentially concerning for true VFP. The average decrease in recruitment of the right and left SLN was 23.8% and 26.1%, respectively. The average decrease in recruitment of the right and left RLN was 37.3% and 57.78%, respectively. Seventy four percent of patients who exhibited abnormal MRI were found to have isolated SLN weakness, and 21% of patients were found to have a combined SLN and ipsilateral RLN weakness. In patients with abnormal CT scans 45% were found to have isolated SLN weakness, and 35% were found to have a combined SLN and RLN weakness. MRI imaging again failed to display any significant degree of paresis. However, abnormal CT results displayed severe CN X paresis in 36.84% vs 1.96% in normal scans. The chance of an abnormal MRI and CT result was 2.78 and 5.55 times greater, respectively, for each increase in the degree of severity of CN X paresis. When looking at the ability of imaging to predict the chance of a patient undergoing surgery, 34.8% of patients with an abnormal MRI underwent surgery compared to just 14.61% of those with normal scans. For CT scans, 35% of patients with an abnormal scan underwent surgery, compared with only 15.69% with normal imaging. When pooled, over 33% of patients with any abnormal imaging underwent a laryngeal procedure compared to 13% of patients with normal imaging. There is a relationship between severity of vocal fold paresis found on laryngeal EMG and likelihood of detection on imaging. While CT was more likely to find characteristics of UVFP than MRI, patients who had an abnormal finding on either modality were more likely to undergo surgical intervention. These findings highlight the importance of early referral of patients with abnormal laryngeal imaging to an otolaryngologist for evaluation and possible intervention.

Safety of Laryngeal Electromyography and Repetitive Stimulation

Laryngeal Electromyography (LEMG) is a procedure used to assess electrical signals from laryngeal muscles. It is considered to be the gold standard test for examining vocal fold paresis/paralysis. Repetitive stimulation studies, which usually are performed at the time of LEMG, can aid in assessment of neuromuscular function. Electromyography poses risks to the patient due to the use of electricity and needles. The purpose of this paper was to evaluate the safety of LEMG and discuss the possible complications. This was a retrospective review of patients from January 2015 through February 2022. Information from patient charts included age, sex, chief complaint, past medical history, family medical history, medications, social history, strobovideolaryngoscopy results, type of paresis, professional voice user status, presence of pacemaker, laryngeal electromyography and repetitive stimulation study results, and reported complications. Complications were considered to be anything that differed from the norm. Pain was included as a complication. Data were analyzed for relationships and significance. Five hundred patients were included. Eighteen of the 500 (3.6%) experienced complications. Four (2.1%) males and 14 (4.5%) females experienced complications. Nine of the 18 (50%) reported pain after the procedure, 1 (5.56%) had excessive bleeding (controlled with pressure), 5 (27.78%) reported voice changes, and 3 (16.67%) experienced difficulty with completion of the procedure. No patients with pacemakers or patients taking anticoagulants had complications, but repetitive stimulation studies were not performed on patients with pacemakers. LEMG and repetitive stimulation studies are safe and effective procedures to examine laryngeal muscles. Repetitive stimulation studies are not recommended for patients with pacemakers.

Aerodynamic Performance and Neuromuscular Control in Patients with Unilateral Vocal Fold Paralysis.

Unilateral vocal fold paralysis (UVFP) causes glottal incompetence and poor vocal efficiency. The influence of laryngeal neuromuscular control on aerodynamics in UVFP remains unclear. This study investigated the relationship between laryngeal muscle activities using quantitative laryngeal electromyography (LEMG) and aerodynamics in UVFP. This prospective study recruited patients with UVFP, and the diagnosis was confirmed with videolaryngostroboscopy and LEMG. The patient received aerodynamic assessment and LEMG of the thyroarytenoid-lateral cricoarytenoid (TA-LCA) muscle complex and the cricothyroid (CT) muscle. The relationship between quantitative LEMG and aerodynamic parameters was analyzed. A total of 134 UVFP patients without concurrent CT muscle involvement were enrolled. Compared with the normal side, the peak turn frequency of the lesioned side was lower in the TA-LCA (p < 0.001) and CT (p = 0.048) muscles. Stepwise linear regression revealed that the turn ratio of TA-LCA muscles was a robust factor in the decrease in peak expiratory airflow (β = -0.34, p = 0.036), mean airflow during voicing (β = -0.28, p = 0.014), and aerodynamic power (β = -0.42, p = 0.019), and an increase in aerodynamic efficiency (β = 27.91, p = 0.012). In addition, the turn ratio of CT muscles was a potent factor in inducing an increase in aerodynamic resistance (β = 14.93, p = 0.029). UVFP without CT involvement still showed suppression of CT muscles on the lesioned side, suggesting that neurological impairment of the TA-LCA complex could cause asymmetrical compensation of CT muscles, further impeding aerodynamics. The residual function of TA-LCA muscle complexes facilitates less air leakage and power dissipation, enhancing aerodynamic efficiency. On the other hand, the symmetrical compensation of the CT muscles improves aerodynamic resistance.

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.

Cricothyroid Dysfunction in Unilateral Vocal Fold Paralysis Females Impairs Lexical Tone Production.

In this cross-sectional study, we compared voice tone and activities relating to the laryngeal muscle between unilateral vocal fold paralysis (UVFP) patients with and without cricothyroid (CT) muscle dysfunction to define how CT dysfunction affects language tone. Eighty-eight female surgery-related UVFP patients were recruited and received acoustic voice analysis and laryngeal electromyography (LEMG) when the patient was producing the four Mandarin tones. The statistical analysis was compared between UVFP patients with (CT+ group, 17 patients) and without CT muscle (CT- group, 71 patients) involvement. When producing Mandarin Tone 2, the voice tone in the CT+ group had smaller rise range (p = 0.007), lower rise rate (p = 0.002), and lower fundamental frequency (F0) at the offset point of the voice (p = 0.023). When producing Mandarin Tone 4, the voice tone in the CT+ group had smaller drop range (p = 0.019), lower drop rate (p = 0.005), and lower F0 at voice onset (p = 0.025). The CT+ group had significantly lower CT muscle activity when producing the four Mandarin tones. In conclusion, CT dysfunction causes a limitation of high-rising tone in Tone 2 and high-falling tone in Tone 4, a property that dramatically limits the tonal characteristics in Mandarin, a tonal language. This limitation could further impair the patient's communication ability.

Positive Predictive Value of Endoscopic Findings to Diagnose Vocal Fold Paresis.

Laryngoscopy corresponding with laryngeal electromyography (LEMG) is essential in diagnosing vocal fold paresis. However, baseline asymmetry or other diseases oftentimes confound the exam, making diagnosis difficult. There is currently no agreed upon endoscopic criteria proven to reliably correlate with LEMG findings. We define a set of endoscopic findings termed "paresis triad" that, when present together, reliably correlate with LEMG. The paresis triad consists of (1) hypocontraction of the weak side of the larynx with increased ventricular show, (2) hypercontraction of the intact side with bulging of the false fold covering the ventricle, and (3) tilting of the interarytenoid cleft to the weak side. We performed a retrospective review of patients with laryngeal asymmetry on laryngoscopy. Patients were divided into two groups: those with consistent paresis triad findings across all pitches and intensities, and those without. All patients underwent LEMG by a neurolaryngologist blinded to the laryngoscopic findings. The endoscopies were then rereviewed in a blinded manner by a second laryngologist to assess inter- and intrarater reliability for identification of the triad. Twelve patients met inclusion criteria (age 50 +/-15, 7F:5M). Nine had the paresis triad. Three had an inconsistent triad. All patients with the paresis triad had LEMG findings consistent with neurologic injury on the suspected side. All patients with inconsistent triad findings had normal LEMG. Our findings suggest the proposed laryngoscopic paresis triad may be useful objective criteria to diagnose paresis without the need for LEMG. Further prospective studies should examine a larger series of patients. 4 Laryngoscope, 133:1712-1716, 2023.

Clinical usefulness of transcutaneous laryngeal ultrasonography in otolaryngology practice during COVID-19 pandemic: a literature review.

As a consequence of the outbreak of SARS-CoV-2, the clinical practice of otolaryngologists underwent profound transformations. Non-aerosol-generating procedures have been researched and implemented. Transcutaneous laryngeal ultrasonography (TLUSG) provides a rapid and noninvasive method to assess laryngeal function and can support the management of laryngeal disorders. With the aim of investigating the clinical usefulness of TLUSG in otolaryngology practice, a review of the literature published on PubMed, Cochrane Library and Ovid/ Medline databases was performed up to March 2022. 38 studies were eligible to be included in the review. The selected papers were divided into six topics of interest: evaluation of vocal cords function, diagnosis of laryngeal disorders in infants and children, evaluation of swallowing disorders, assessment of laryngeal cancer and other laryngeal lesions, ultrasound-guided cricothyroidotomy, ultrasound-guided laryngeal electromyography. The results of this review demonstrated that TLUSG, applied to ENT practice, can be a valid method for dynamic laryngeal assessment and airway management, since it is time-efficient, non invasive, well tolerated and easily performed.

A comparison between cisatracurium and rocuronium-induced neuromuscular block on laryngeal electromyography recovery after neostigmine reversal in a porcine model.

BackgroundInducing and reversing neuromuscular block is essential to a positive outcome of thyroid surgery, with intraoperative neuromonitoring (IONM) being used to decrease recurrent and superior laryngeal nerve injuries and improve vocal outcome. Neostigmine is a non-specific broad-spectrum and inexpensive reversal agent for neuromuscular blocking agents (NMBAs). The aim of this porcine study was to explore the effect of neostigmine on electromyography (EMG) signal recovery profile following the commonly used NMBAs, cisatracurium and rocuronium.MethodsTwelve piglets were allocated into two groups with six piglets in each group. When stable baseline EMG signals were obtained, a neuromuscular block was induced by intravenous cisatracurium 0.2 mg/kg (group C) or rocuronium 0.6 mg/kg (group R) for each piglet. We compared laryngeal EMG tracing with spontaneous recovery (control) and neostigmine (0.04 mg/kg) reversal for each group. The time course of real-time laryngeal EMG signals was observed for 30 min from NMBA injection. Effects of neostigmine on EMG signal were assessed at 50% EMG recovery and by the maximum neuromuscular block recovery degree from the baseline value.ResultsNeostigmine shortened the recovery time to 50% EMG amplitude in both group C (16.5 [2.5] vs. 29.0 [2.0] min, P<0.01) and group R (16.5[2.5] vs. 26.5 [1.5] min, P<0.05) compared to spontaneous recovery, respectively. Neostigmine reversal also enhanced the maximum degree of EMG amplitude recovery in both group C (83.6 [5.1] vs. 47.2 [6.1] %, P<0.01) and group R (85.6 [18.2]vs. 57.1 [6.3] %, P<0.05) compared to spontaneous recovery, respectively. The reversal effect of neostigmine did not differ significantly between cisatracurium and rocuronium.ConclusionsThis porcine model demonstrated that neostigmine provides an adequate and timely IONM signal suppressed by both cisatracurium and rocuronium. These results can potentially expand the options for precision neuromuscular block management during IONM to improve vocal outcomes in thyroid surgery patients.

Laryngeal electromyography, a useful tool in difficult cases of pediatric laryngeal mobility disorders

IntroductionPediatric laryngeal mobility disorders constitute a challenge in terms of diagnosis and treatment, especially in small children and those complex patients with prior history of prolonged intubation or surgery. Laryngeal electromyography (L-EMG) may help to distinguish vocal fold paralysis from fixation. Material and methodsTen children with laryngeal mobility disorders (including bilateral vocal fold immobility (BVFI) or unilateral vocal fold immobility (UVFI) with contralateral hypomobility) underwent suspension laryngoscopy and L-EMG between July 2019 and March 2021. The EMG data were acquired simultaneously in both thyroarytenoid muscles. Anesthesia was lightened until volitional activity appeared like cough, cry or spontaneous Valsalva maneuver. ResultsWe found secondary airway lesions in 2 patients and 3 vocal fold fixation. L-EMG recordings were pathologic in 4 patients (3 moderate and 1 severe nerve lesion). No recurrent laryngeal nerve injury was found in congenital BVFI cases. The data from both suspension laryngoscopy and L-EMG recordings influenced clinical decision-making. ConclusionsL-EMG adds value to suspension laryngoscopy in the management of pediatric patients with laryngeal mobility disorders. Selected cases such as patients with iatrogenic BVFI, UVFI with associated contralateral hypomobility or patients with combined pathologies may obtain the greatest benefit.

Exploring the Clinical Characteristics of Superior Laryngeal Nerve Injury

To observe the cases of superior laryngeal nerve injury along with summarizing and analyzing its clinical characteristics. A total of 14 patients with unilateral superior laryngeal nerve injury (SLN) diagnosed by laryngeal electromyography (LEMG) in our department from 2018 to 2020 were collected as SLN injury group. A total of 14 healthy subjects with normal laryngeal electromyography were recruited as normal group matched by age and sex. The etiology and LEMG of the SLN injury group were analyzed, and the video stroboscopic manifestations of SLN injury group and normal group were compared to see the characteristic video stroboscopic manifestations of SLN injury. The most common causes of SLN injury were surgery and idiopathic etiology. Compared with normal group, the most frequent video stroboscopic manifestations of SLN injury group were vocal fold dyskinesia. Abnormal video stroboscopic manifestations occurred in normal group except larynx deviation, epiglottic petiole deviation, and dyskinesia. There was a significant difference between the two groups in various abnormal video stroboscopic manifestations (P < 0.05). Time limit widening was the most common manifestation of LEMG. Vocal fold dyskinesia was a prominent finding in SLN injury, laryngeal deviation and epiglottic petiole deviation were relative specific signs of SLN injury. Vocal fold bowing combined with shortening will contribute to the diagnosis of SLN injury. There were no specific diagnostic signs for SLN injury, clinicians need further LEMG for a firm diagnosis.