Randomized Trial of Metformin, Ivermectin, and Fluvoxamine for Covid-19.

BACKGROUND: Early treatment to prevent severe coronavirus disease 2019 (Covid-19) is an important component of the comprehensive response to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. METHODS: In this phase 3, double-blind, randomized, placebo-controlled trial, we used a 2-by-3 factorial design to test the effectiveness of three repurposed drugs - metformin, ivermectin, and fluvoxamine - in preventing serious SARS-CoV-2 infection in nonhospitalized adults who had been enrolled within 3 days after a confirmed diagnosis of infection and less than 7 days after the onset of symptoms. The patients were between the ages of 30 and 85 years, and all had either overweight or obesity. The primary composite end point was hypoxemia (≤93% oxygen saturation on home oximetry), emergency department visit, hospitalization, or death. All analyses used controls who had undergone concurrent randomization and were adjusted for SARS-CoV-2 vaccination and receipt of other trial medications. RESULTS: A total of 1431 patients underwent randomization; of these patients, 1323 were included in the primary analysis. The median age of the patients was 46 years; 56% were female (6% of whom were pregnant), and 52% had been vaccinated. The adjusted odds ratio for a primary event was 0.84 (95% confidence interval [CI], 0.66 to 1.09; P = 0.19) with metformin, 1.05 (95% CI, 0.76 to 1.45; P = 0.78) with ivermectin, and 0.94 (95% CI, 0.66 to 1.36; P = 0.75) with fluvoxamine. In prespecified secondary analyses, the adjusted odds ratio for emergency department visit, hospitalization, or death was 0.58 (95% CI, 0.35 to 0.94) with metformin, 1.39 (95% CI, 0.72 to 2.69) with ivermectin, and 1.17 (95% CI, 0.57 to 2.40) with fluvoxamine. The adjusted odds ratio for hospitalization or death was 0.47 (95% CI, 0.20 to 1.11) with metformin, 0.73 (95% CI, 0.19 to 2.77) with ivermectin, and 1.11 (95% CI, 0.33 to 3.76) with fluvoxamine. CONCLUSIONS: None of the three medications that were evaluated prevented the occurrence of hypoxemia, an emergency department visit, hospitalization, or death associated with Covid-19. (Funded by the Parsemus Foundation and others; COVID-OUT ClinicalTrials.gov number, NCT04510194.).

Simultaneous cortical, subcortical, and brainstem mapping of sensory activation.

Nonpainful tactile sensory stimuli are processed in the cortex, subcortex, and brainstem. Recent functional magnetic resonance imaging studies have highlighted the value of whole-brain, systems-level investigation for examining sensory processing. However, whole-brain functional magnetic resonance imaging studies are uncommon, in part due to challenges with signal to noise when studying the brainstem. Furthermore, differentiation of small sensory brainstem structures such as the cuneate and gracile nuclei necessitates high-resolution imaging. To address this gap in systems-level sensory investigation, we employed a whole-brain, multi-echo functional magnetic resonance imaging acquisition at 3T with multi-echo independent component analysis denoising and brainstem-specific modeling to enable detection of activation across the entire sensory system. In healthy participants, we examined patterns of activity in response to nonpainful brushing of the right hand, left hand, and right foot (n = 10 per location), and found the expected lateralization, with distinct cortical and subcortical responses for upper and lower limb stimulation. At the brainstem level, we differentiated the adjacent cuneate and gracile nuclei, corresponding to hand and foot stimulation respectively. Our findings demonstrate that simultaneous cortical, subcortical, and brainstem mapping at 3T could be a key tool to understand the sensory system in both healthy individuals and clinical cohorts with sensory deficits.

Favorable Antiviral Effect of Metformin on Severe Acute Respiratory Syndrome Coronavirus 2 Viral Load in a Randomized, Placebo-Controlled Clinical Trial of Coronavirus Disease 2019.

BACKGROUND: Metformin has antiviral activity against RNA viruses including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The mechanism appears to be suppression of protein translation via targeting the host mechanistic target of rapamycin pathway. In the COVID-OUT randomized trial for outpatient coronavirus disease 2019 (COVID-19), metformin reduced the odds of hospitalizations/death through 28 days by 58%, of emergency department visits/hospitalizations/death through 14 days by 42%, and of long COVID through 10 months by 42%. METHODS: COVID-OUT was a 2 × 3 randomized, placebo-controlled, double-blind trial that assessed metformin, fluvoxamine, and ivermectin; 999 participants self-collected anterior nasal swabs on day 1 (n = 945), day 5 (n = 871), and day 10 (n = 775). Viral load was quantified using reverse-transcription quantitative polymerase chain reaction. RESULTS: The mean SARS-CoV-2 viral load was reduced 3.6-fold with metformin relative to placebo (-0.56 log10 copies/mL; 95% confidence interval [CI], -1.05 to -.06; P = .027). Those who received metformin were less likely to have a detectable viral load than placebo at day 5 or day 10 (odds ratio [OR], 0.72; 95% CI, .55 to .94). Viral rebound, defined as a higher viral load at day 10 than day 5, was less frequent with metformin (3.28%) than placebo (5.95%; OR, 0.68; 95% CI, .36 to 1.29). The metformin effect was consistent across subgroups and increased over time. Neither ivermectin nor fluvoxamine showed effect over placebo. CONCLUSIONS: In this randomized, placebo-controlled trial of outpatient treatment of SARS-CoV-2, metformin significantly reduced SARS-CoV-2 viral load, which may explain the clinical benefits in this trial. Metformin is pleiotropic with other actions that are relevant to COVID-19 pathophysiology. CLINICAL TRIALS REGISTRATION: NCT04510194.

A cross exploratory analysis between nursing working conditions and the occurrence of errors in the northeast region of Brazil.

OBJECTIVES: Analyze and verify the association between working conditions and the occurrence of errors in nursing work. BACKGROUND: Many of the known errors in nursing are based on the structural failure of the complex health service system. Our study addresses the question "Is there an association between errors made by nursing workers and working conditions?" METHODS: The study was carried out through a cross-sectional exploratory analysis of 19 ethical-disciplinary processes focused on errors made by nursing workers. The articles were processed, judged, and archived at the Regional Nursing Councils of the Northeast Region of Brazil from 2000 to 2018. The chi-square test or Fisher's exact test was used to verify the relationship between the variables through multivariate analysis. RESULTS: The analyzes show that working conditions can interfere at occurrence in error. This increases the chance of an "inconsequential" error occurring for the patient in poor/very poor working conditions. The most serious errors, "with consequences irreversible" for the patient, only occur from more severe working conditions. Adversely, it was found that there is no statistically significant difference in the frequency of errors in hospitals (33.33 %) compared to "other places" (28.58 %) when these occurred in poor working conditions. When conducting the incident in poor working conditions, there was a minimum of 52 % protection OR = 0.48 % [0.16; 11.80]; (1-0.48)) against these errors in general in the nursing area. CONCLUSION: The strong association was exposed in working conditions classified as bad/very bad/very bad, resulting in the most serious errors and with irreversible consequences for patients. However, a level of protection for different types of workers was noticed in the field, which shows that there is hope that if the work environment changes with more organization, management, and standards of care, we can prevent future errors.

Impact of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Vaccination and Booster on Coronavirus Disease 2019 (COVID-19) Symptom Severity Over Time in the COVID-OUT Trial.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination has decreasing protection from acquiring any infection with emergence of new variants; however, vaccination continues to protect against progression to severe coronavirus disease 2019 (COVID-19). The impact of vaccination status on symptoms over time is less clear. METHODS: Within a randomized trial on early outpatient COVID-19 therapy testing metformin, ivermectin, and/or fluvoxamine, participants recorded symptoms daily for 14 days. Participants were given a paper symptom diary allowing them to circle the severity of 14 symptoms as none (0), mild (1), moderate (2), or severe (3). This is a secondary analysis of clinical trial data on symptom severity over time using generalized estimating equations comparing those unvaccinated, SARS-CoV-2 vaccinated with primary vaccine series only, or vaccine-boosted. RESULTS: The parent clinical trial prospectively enrolled 1323 participants, of whom 1062 (80%) prospectively recorded some daily symptom data. Of these, 480 (45%) were unvaccinated, 530 (50%) were vaccinated with primary series only, and 52 (5%) vaccine-boosted. Overall symptom severity was least for the vaccine-boosted group and most severe for unvaccinated at baseline and over the 14 days (P < .001). Individual symptoms were least severe in the vaccine-boosted group including cough, chills, fever, nausea, fatigue, myalgia, headache, and diarrhea, as well as smell and taste abnormalities. Results were consistent over Delta and Omicron variant time periods. CONCLUSIONS: SARS-CoV-2 vaccine-boosted participants had the least severe symptoms during COVID-19, which abated the quickest over time. Clinical Trial Registration. NCT04510194.

Top advances of the year: Precision oncology.

The advent of precision medicine has changed the landscape of oncologic biomarkers, drug discovery, drug development, and, more importantly, outcomes for patients with cancer. Precision oncology entails the genomic profiling of tumors to detect actionable aberrations. The advances in clinical next-generation sequencing from both tumor tissue and liquid biopsy and availability of targeted therapies has rapidly entered mainstream clinical practice. In this review, recent major developments in precision oncology that have affected outcomes for patients with cancer are discussed. Rapid clinical development was seen of targeted agents across various mutational profiles such as KRASG12C (which was considered "undruggable" for almost 4 decades), Exon 20 insertions, and RET mutations. Approaches to precision chemotherapy delivery by the introduction of antibody drug conjugates in the armamentarium against lung cancer has been appreciated.

Cardiovascular risk factor profiles in North and South Indian and Pakistani Americans: The MASALA Study.

South Asians in the United States have disproportionately high burden of cardiovascular disease compared to other race/ethnic groups but are a heterogenous population, so we evaluated differences in prevalence and adjusted odds of cardiovascular risk factors including diabetes, hypertension, dyslipidemia, and obesity between North Indian, South Indian, and Pakistani immigrants in the United States in the Mediators of Atherosclerosis in South Asians Living in America (MASALA) study. Given cultural differences among residents of Indian regions, for example in dietary patterns, we categorized Indian participants as North or South Indian. In 1,018 participants (728 North Indian [47% women], 223 South Indian [43% women], 67 Pakistani [52% women]), unadjusted diabetes and obesity prevalence was highest in Pakistani participants (33% and 48%, respectively); hypertension prevalence was highest in North Indian participants (54%); dyslipidemia prevalence was highest in South Indian and Pakistani participants (55%); and South Indian participants had a higher odds of dyslipidemia (OR 1.77, 95% CI 1.27, 2.47) compared with North Indian participants in fully adjusted models. As differences in cardiovascular risk factors were observed across South Asian American subgroups, identifying the determinants of suboptimal cardiovascular health within South Asian American subgroups may help to better tailor cardiovascular disease prevention strategies.

A Scoping Review on the Concept of Physician Caring.

BACKGROUND: Physicians' interest in the health and well-being of their patients is a tenet of medical practice. Physicians' ability to act upon this interest by caring for and about their patients is central to high-quality clinical medicine and may affect burnout. To date, a strong theoretical and empirical understanding of physician caring does not exist. To establish a practical, evidence-based approach to improve health care delivery and potentially address physician burnout, we sought to identify and synthesize existing conceptual models, frameworks, and definitions of physician caring. METHODS: We performed a scoping review on physician caring. In November 2019 and September 2020, we searched PubMed MEDLINE, Embase, PsycINFO, CINAHL, and CENTRAL Register of Controlled Trials to identify conceptual models, frameworks, and definitions of physician caring. Eligible articles involved discussion or study of care or caring among medical practitioners. We created a content summary and performed thematic analysis of extracted data. RESULTS: Of 11,776 articles, we reviewed the full text of 297 articles; 61 articles met inclusion criteria. Commonly identified concepts referenced Peabody's "secret of care" and the ethics of care. In bioethics, caring is described as a virtue. Contradictions exist among concepts of caring, such as whether caring is an attitude, emotion, or behavior, and the role of relationship development. Thematic analysis of all concepts and definitions identified six aspects of physician caring: (1) relational aspects, (2) technical aspects, (3) physician attitudes and characteristics, (4) agency, (5) reciprocity, and (6) physician self-care. DISCUSSION: Caring is instrumental to clinical medicine. However, scientific understanding of what constitutes caring from physicians is limited by contradictions across concepts. A unifying concept of physician caring does not yet exist. This review proposes six aspects of physician caring which can be used to develop evidence-based approaches to improve health care delivery and potentially mitigate physician burnout.

Tele-buprenorphine for emergency department overdose visit follow up and treatment initiation.

INTRODUCTION: An ED visit for opioid overdose may be a person's only contact with the medical and behavioral health care systems and is an important opportunity to reduce risk of subsequent overdose and death. While ED initiatives to engage people with opioid use disorder (OUD) are being increasingly implemented, there are significant gaps in the receipt of services at the time of the ED encounter. METHODS: This is a retrospective cohort study of an outreach pilot project providing real-time telehealth delivered buprenorphine initiation and referral to community harm reduction and addiction treatment services via a follow up telephone call to patients after an ED visit for an opioid overdose. RESULTS: From January 2020 to April 2021 there were 606 patients with an ED visit for an opioid overdose eligible for a callback. Of the 606 eligible patients, 254/645 (42%) patients could be contacted and accepted service and/or treatment referrals. Fifteen patients were connected same-day to a buprenorphine prescriber for a telehealth encounter and, of connected patients, nine received a buprenorphine prescription. CONCLUSION: A post-ED follow up telephone call protocol is an opportunity to improve treatment engagement and access to buprenorphine for patients at high risk for opioid overdose and death.

Integrating reproductive health care into substance use disorder services.

People who use drugs face layered stigma and barriers to accessing reproductive health care services. At the same time, they have unique needs for compassionate, trauma-informed, low-barrier reproductive health care. We review the literature on collocated reproductive health care and substance use treatment services in this population and advocate for expansion of reproductive health care services at sites providing care for substance use disorder. Through this review article, we outline the evidence for and best practices in collocating reproductive health care within substance use disorder services.

Mycoplasma genitalium and Trichomonas vaginalis: addressing disparities and promoting public health control of two emerging sexually transmitted infections.

PURPOSE OF REVIEW: Mycoplasma genitalium (M. genitalium) and Trichomonas vaginalis (T. vaginalis), sexually transmitted infections that remain non-reportable in the United States, may lead to pelvic inflammatory disease (PID) and adverse pregnancy outcomes if left untreated. Prevalence estimates have highlighted socioeconomic and racial/ethnic disparities in rates of infection. This review summarizes the recent literature on M. genitalium and T. vaginalis with a focus on the epidemiology, screening, and treatment of M. genitalium and T. vaginalis. RECENT FINDINGS: The burden of T. vaginalis testing remains on women. Antimicrobial resistance is of great concern for M. genitalium. Comprehensive screening and treatment guidelines present an opportunity to address these public health concerns. SUMMARY: M. genitalium and T. vaginalis infections disproportionately affect sexual and racial/ethnic minorities and those facing socioeconomic disparities. The availability of nucleic acid amplification test testing has facilitated accurate diagnosis of both disorders. Safe and efficacious treatments are available for treatment of both disorders. Integrating macrolide resistance testing into treatment algorithms for M. genitalium and dual antibiotic therapy may prove a useful strategy for future US-based guidance. Public health reporting and increased public awareness campaigns are key next steps to addressing the observed reproductive health disparities.

Early prediction of clinical response in first episode schizophrenia (FES) patients receiving olanzapine.

Background: At present, schizophrenia guidelines recommend waiting for 8 weeks before considering a patient as non-responder. This study aims to detect the optimal early response threshold that best predict the final outcome of olanzapine.Methods: The study was conducted for 8-week, four points follow up (week 2,3,4, and 8) prospective observational study. A reduction of 20, 25, 30% in Positive and Negative Syndrome Scale (PANSS) score from the base line at week 2,3, and 4 respectively were considered as early response. A reduction of 50% at week 8 was considered as responders. Receiver Operating Characteristics (ROC) curves were performed to detect the optimal threshold.Results: Mean total baseline PANSS score was 106.66(95% CI; 100.4, 112.9). Week 2 (AUC = 50.5%, p > 0.964) and week 3 (AUC = 64.9, p > 0.13) responses failed to predict the 8th week response. Week 4 response (AUC = 92%, p < 0.001) can be taken for the prediction of 8th week response (specificity = 72%, sensitivity = 100%, Positive Predictive Value = 61.1%, Negative Predictive Value = 100% and Optimum Early Response (OER) = 29.4%). 25 patients (69%) achieved more than 50% reduction (responders) in PANSS score after 8 weeks of treatment.Conclusions: Our study suggests that patients with early response at week 4 are likely to achieve positive response after 8 weeks. This may help in appropriate clinical decision making for early non-responders.Key PointsThe early response can forecast the outcome at the endpoint for the treatment of FESA reduction of baseline PANSS score by 30% or more after four weeks are likely to have remission after week 8 with olanzapine therapy.

Effects of Thyroarytenoid Activation Induced Vibratory Asymmetry on Voice Acoustics and Perception.

INTRODUCTION: Asymmetry of vocal fold (VF) vibration is common in patients with voice complaints and also observed in 10% of normophonic individuals. Although thyroarytenoid (TA) muscle activation plays a crucial role in regulating VF vibration, how TA activation asymmetry relates to voice acoustics and perception is unclear. We evaluated the relationship between TA activation asymmetry and the resulting acoustics and perception. METHODS: An in vivo canine model of phonation was used to create symmetric and increasingly asymmetric VF vibratory conditions via graded stimulation of bilateral TA muscles. Naïve listeners (n = 89) rated the perceptual quality of 100 unique voice samples using a visual sort-and-rate task. For each phonatory condition, cepstral peak prominence (CPP), harmonic amplitude (H1-H2), and root-mean-square (RMS) energy of the voice were measured. The relationships between these metrics, vibratory asymmetry, and perceptual ratings were evaluated. RESULTS: Increasing levels of TA asymmetry resulted in declining listener preference. Furthermore, only severely asymmetric audio samples were perceptually distinguishable from symmetric and mildly asymmetric conditions. CPP was negatively correlated with TA asymmetry: voices produced with larger degrees of asymmetry were associated with lower CPP values. Listeners preferred audio samples with higher values of CPP, high RMS energy, and lower H1-H2 (less breathy). CONCLUSION: Listeners are sensitive to changes in voice acoustics related to vibratory asymmetry. Although increasing vibratory asymmetry is correlated with decreased perceptual ratings, mild asymmetries are perceptually tolerated. This study contributes to our understanding of voice production and quality by identifying perceptually salient and clinically meaningful asymmetry. LEVEL OF EVIDENCE: N/A (Basic Science Study) Laryngoscope, 134:1327-1332, 2024.

Histologic Examination of Vocal Fold Mucosal Wave and Vibration.

OBJECTIVES: Despite gross anatomic and histologic differences between human and canine vocal folds, similar wave patterns have been described yet not fully characterized. We reconstructed vocal fold (VF) vibration in a canine hemilarynx and performed histologic examination of the same vocal fold. We demonstrate comparable wave patterns while exploring the importance of certain anatomic architectures. METHODS: An in vivo canine hemilarynx was phonated against a glass prism at low and high muscle activation conditions. Vibration was captured using high-speed video, and trajectories of VF medial surface tattooed landmarks were 3D-reconstructed. The method of empirical eigenfunctions was used to capture the essential dynamics of vibratory movement. Histologic examination of the hemilarynx was performed. RESULTS: Oscillation patterns were highly similar between the in vivo canine and previous reports of ex vivo human models. The two most dominant eigenfunctions comprised over 90% of total variance of movement, representing opening/closing and convergent/divergent movement patterns, respectively. We demonstrate a vertical phase difference during the glottal cycle. The time delay between the inferior and superior VF was greater during opening than closing for both activation conditions. Histological examination of canine VF showed not only a thicker lamina propria layer superiorly but also a distinct pattern of thyroarytenoid muscle fibers and fascicles as described in human studies. CONCLUSIONS: Histologic and vibratory examination of the canine vocal fold demonstrated human vocal fold vibratory patterns despite certain microstructural differences. This study suggests that the multilayered lamina propria may not be fundamental to vibratory patterns necessary for human-like voice production. LEVEL OF EVIDENCE: NA (Basic science study) Laryngoscope, 134:264-271, 2024.

Cell-Based Outer Vocal Fold Replacement Both Treats and Prevents Vocal Fold Scarring in Rabbits.

OBJECTIVE: Numerous pharmacological and cell-based treatments have shown promise in preventing vocal fold (VF) scarring when applied at the time of injury. A common clinical scenario, however, is the finding of mature scar impeding voicing. Many treatments are less effective in remodeling existing scar tissue. This objective of this study is to determine if a cell-based outer vocal fold replacement (COVR) effectively restores VF function when applied to existing scar. METHODS: Eighteen rabbits were allocated to three groups: unilateral COVR implant at the time of cordectomy (acute COVR); unilateral cordectomy followed by COVR implant 2 months later (chronic COVR); and unilateral cordectomy followed by sham implant surgery 2 months later (chronic scar). Larynges were harvested 2 months after implant or sham surgery. RESULTS: All larynges in the COVR groups demonstrated human leukocyte antigen labeling on immunohistochemistry (IHC). COVR groups had increased hyaluronic acid content compared with normal. VF stiffness as measured by elastic moduli in acute COVR and chronic COVR were similar to their contralateral unoperated VF. CONCLUSION: COVR implantation in both acutely injured and chronically scarred VF demonstrate persistence of implanted cells, restored tissue biomechanics, and increased hyaluronic acid content. LEVEL OF EVIDENCE: NA Laryngoscope, 134:764-772, 2024.

Simultaneous cortical, subcortical, and brainstem mapping of sensory activation.

Non-painful tactile sensory stimuli are processed in the cortex, subcortex, and brainstem. Recent functional magnetic resonance imaging (fMRI) studies have highlighted the value of whole-brain, systems-level investigation for examining pain processing. However, whole-brain fMRI studies are uncommon, in part due to challenges with signal to noise when studying the brainstem. Furthermore, the differentiation of small sensory brainstem structures such as the cuneate and gracile nuclei necessitates high resolution imaging. To address this gap in systems-level sensory investigation, we employed a whole-brain, multi-echo fMRI acquisition at 3T with multi-echo independent component analysis (ME-ICA) denoising and brainstem-specific modeling to enable detection of activation across the entire sensory system. In healthy participants, we examined patterns of activity in response to non-painful brushing of the right hand, left hand, and right foot, and found the expected lateralization, with distinct cortical and subcortical responses for upper and lower limb stimulation. At the brainstem level, we were able to differentiate the small, adjacent cuneate and gracile nuclei, corresponding to hand and foot stimulation respectively. Our findings demonstrate that simultaneous cortical, subcortical, and brainstem mapping at 3T could be a key tool to understand the sensory system in both healthy individuals and clinical cohorts with sensory deficits.

Characterizing opioid overdose hotspots for place-based overdose prevention and treatment interventions: A geo-spatial analysis of Rhode Island, USA.

OBJECTIVE: Examine differences in neighborhood characteristics and services between overdose hotspot and non-hotspot neighborhoods and identify neighborhood-level population factors associated with increased overdose incidence. METHODS: We conducted a population-based retrospective analysis of Rhode Island, USA residents who had a fatal or non-fatal overdose from 2016 to 2020 using an environmental scan and data from Rhode Island emergency medical services, State Unintentional Drug Overdose Reporting System, and the American Community Survey. We conducted a spatial scan via SaTScan to identify non-fatal and fatal overdose hotspots and compared the characteristics of hotspot and non-hotspot neighborhoods. We identified associations between census block group-level characteristics using a Besag-York-Mollié model specification with a conditional autoregressive spatial random effect. RESULTS: We identified 7 non-fatal and 3 fatal overdose hotspots in Rhode Island during the study period. Hotspot neighborhoods had higher proportions of Black and Latino/a residents, renter-occupied housing, vacant housing, unemployment, and cost-burdened households. A higher proportion of hotspot neighborhoods had a religious organization, a health center, or a police station. Non-fatal overdose risk increased in a dose responsive manner with increasing proportions of residents living in poverty. There was increased relative risk of non-fatal and fatal overdoses in neighborhoods with crowded housing above the mean (RR 1.19 [95 % CI 1.05, 1.34]; RR 1.21 [95 % CI 1.18, 1.38], respectively). CONCLUSION: Neighborhoods with increased prevalence of housing instability and poverty are at highest risk of overdose. The high availability of social services in overdose hotspots presents an opportunity to work with established organizations to prevent overdose deaths.

3D Reconstruction of Phonatory Glottal Shape and Volume: Effects of Neuromuscular Activation.

INTRODUCTION: Although phonatory glottal posture and airflow pulse shape affect voice quality, studies to date have been limited by visualization of vocal fold (VF) vibration from a superior view. We performed a 3D reconstruction of VF vibratory motion during phonation from a medial view and assessed the glottal volume waveform and resulting acoustics as a function of neuromuscular stimulation. STUDY DESIGN: In vivo canine hemilarynx phonation. METHODS: Across 121 unique combinations of the superior laryngeal nerve (SLN) and recurrent laryngeal nerve (RLN) stimulation, the hemilarynx was excited to the oscillation with airflow. VF medial surface reference points were tracked on high-speed video, mapped into 3D space, and surface shape was restored using cubic spline interpolation. Glottal surface shape, reconstruction-based parameters, and glottal volume waveform were calculated. Fundamental frequency (F0), cepstral peak prominence (CPP), and harmonic amplitude (H1-H2) were measured from high-quality audio samples. RESULTS: The glottis was convergent during opening and divergent during closing. Neuromuscular activation changed phonatory glottal shape and reduced glottal volume. Significant reduction in glottal volume and closing quotient were present with SLN stimulation. RLN stimulation significantly increased F0 and CPP and decreased H1-H2 (constricted glottis), while SLN effects were similar and synergistic with concurrent RLN stimulation. CONCLUSION: 3D reconstruction of in vivo medial surface vibration revealed effects of laryngeal nerve stimulation on glottal vibratory pattern and acoustic correlates of voice quality. SLN activation resulted in significantly quicker glottal closure per cycle, decreased glottal volume, and higher-pitched, less breathy, and less noisy voice. RLN had a similar effect on acoustic measures. LEVEL OF EVIDENCE: NA, Basic Science Laryngoscope, 133:357-365, 2023.

Control of Pre-phonatory Glottal Shape by Intrinsic Laryngeal Muscles.

OBJECTIVES: Surgical manipulations to treat glottic insufficiency aim to restore the physiologic pre-phonatory glottal shape. However, the physiologic pre-phonatory glottal shape as a function of interactions between all intrinsic laryngeal muscles (ILMs) has not been described. Vocal fold posture and medial surface shape were investigated across concurrent activation and interactions of thyroarytenoid (TA), cricothyroid (CT), and lateral cricoarytenoid/interarytenoid (LCA/IA) muscles. STUDY DESIGN: In vivo canine hemilarynx model. METHODS: The ILMs were stimulated across combinations of four graded levels each from low-to-high activation. A total of 64 distinct medial surface postures (4 TA × 4 CT × 4 LCA/IA levels) were captured using high-speed video. Using a custom 3D interpolation algorithm, the medial surface shape was reconstructed. RESULTS: Combined activation of ILMs yielded a range of unique pre-phonatory postures. Both LCA/IA and TA activation adducted the vocal fold but with greater contribution from TA. The transition from a convergent to a rectangular glottal shape was primarily mediated by TA muscle activation but LCA/IA and TA together resulted in a smooth rectangular glottis compared to TA alone, which caused rectangular glottis with inferomedial bulging. CT activation resulted in a lengthened but slightly abducted glottis. CONCLUSIONS: TA was primarily responsible for the rectangular shape of the adducted glottis with synergistic contribution from the LCA/IA. CT contributed minimally to vocal fold medial shape but elongated the glottis. These findings further refine laryngeal posture goals in surgical correction of glottic insufficiency. LEVEL OF EVIDENCE: NA, Basic science Laryngoscope, 133:1690-1697, 2023.