Conducting high-quality and reliable acoustic analysis: A tutorial focused on training research assistants.

Open science practices have led to an increase in available speech datasets for researchers interested in acoustic analysis. Accurate evaluation of these databases frequently requires manual or semi-automated analysis. The time-intensive nature of these analyses makes them ideally suited for research assistants in laboratories focused on speech and voice production. However, the completion of high-quality, consistent, and reliable analyses requires clear rules and guidelines for all research assistants to follow. This tutorial will provide information on training and mentoring research assistants to complete these analyses, covering areas including RA training, ongoing data analysis monitoring, and documentation needed for reliable and re-creatable findings.

Analysis of factors on voice quality in thyroidectomy patients.

OBJECTIVE: Vocal cord paralysis (VCP) is a serious complication in thyroidectomy operations; however, its management remains unclear. The present study evaluated the voice parameters of patients who underwent surgery using Intraoperative Neurophysiologic Monitoring (IONM). PATIENTS AND METHODS: A total of 52 patients (41 females and 11 males) who underwent a total thyroidectomy operation were evaluated using objective and subjective voice analysis examinations before and after surgery. Acoustic parameters, such as Fundamental Frequency (F0), Shimmer, Jitter, Noise-to-Harmonic ratio (NHR), and aerodynamic parameters, including S/Z ratio and maximum phonation time (MPT), were analyzed. Objective findings, including the VHI-10 (Voice Handicap Index) and V-RQOL (Voice-Related Quality of Life), were also analyzed. The relationship between voice parameters and IONM values was investigated. RESULTS: The objective analysis (acoustic and aerodynamic parameters) showed no difference (p>0.05). However, the subjective analysis, which involved the VHI-10 and V-RQOL measures, revealed a significant difference before and after the operation (p<0.05). The Spearman correlation analysis showed that the NHR postoperative 1st-month parameter negatively correlated (rho=-0.317, p<0.059), while the F0 postoperative 6th-month parameter positively correlated (rho=0.347) with the amplitude difference before and after dissection (Right R2-R1 difference) for the right RLN measured in IONM. CONCLUSIONS: Patients who are planning to undergo a thyroidectomy procedure should undergo voice assessment during both the preoperative and postoperative periods. IONM could improve voice quality outcomes.

Factors associated with voice-related quality of life among patients with temporomandibular disorders.

BACKGROUND: Research would be important for obtaining a better understanding of voice complaints among patients with temporomandibular disorders (TMD). OBJECTIVE: The identification of predictors of voice disorders associated with TMD pain was made according to Diagnostic Criteria for TMD (DC/TMD) Axis I. METHODOLOGY: Functional limitations were measured using the Jaw Functional Limitation Scales for mastication (JFLS-M), jaw mobility (JFLS-JM), and verbal and emotional expression (JFLS-VEE). Patients also completed the Hospital Anxiety and Depression Scale (HADS). The primary outcome was social-emotional and physical functioning as indicated by scores on the Voice-Related Quality of Life (V-RQOL) questionnaire. Multiple linear regression was used to model the relationship between the domains on the V-RQOL questionnaire and scores on the HADS and JFLS after adjusting for age, gender, DC/TMD diagnosis, pain intensity, and time since pain onset. RESULTS: The HADS-D (B=-1.15; 95% CI, -1.718 to -0.587; p<.001) and JFLS-VEE (B=-0.22; 95% CI, -0.40 to -0.06; p=.008) were significant predictors of scores on the V-RQOL questionnaire. CONCLUSION: Higher scores on depression measures and limitations in verbal and emotional expression could exacerbate voice problems among TMD pain patients. Future research should promote multidisciplinary treatments for TMD pain-related voice disorders.

Speaking without vocal folds using a machine-learning-assisted wearable sensing-actuation system.

Voice disorders resulting from various pathological vocal fold conditions or postoperative recovery of laryngeal cancer surgeries, are common causes of dysphonia. Here, we present a self-powered wearable sensing-actuation system based on soft magnetoelasticity that enables assisted speaking without relying on the vocal folds. It holds a lightweighted mass of approximately 7.2 g, skin-alike modulus of 7.83 × 105 Pa, stability against skin perspiration, and a maximum stretchability of 164%. The wearable sensing component can effectively capture extrinsic laryngeal muscle movement and convert them into high-fidelity and analyzable electrical signals, which can be translated into speech signals with the assistance of machine learning algorithms with an accuracy of 94.68%. Then, with the wearable actuation component, the speech could be expressed as voice signals while circumventing vocal fold vibration. We expect this approach could facilitate the restoration of normal voice function and significantly enhance the quality of life for patients with dysfunctional vocal folds.

Voice disorder recognition using machine learning: a scoping review protocol.

INTRODUCTION: Over the past decade, several machine learning (ML) algorithms have been investigated to assess their efficacy in detecting voice disorders. Literature indicates that ML algorithms can detect voice disorders with high accuracy. This suggests that ML has the potential to assist clinicians in the analysis and treatment outcome evaluation of voice disorders. However, despite numerous research studies, none of the algorithms have been sufficiently reliable to be used in clinical settings. Through this review, we aim to identify critical issues that have inhibited the use of ML algorithms in clinical settings by identifying standard audio tasks, acoustic features, processing algorithms and environmental factors that affect the efficacy of those algorithms. METHODS: We will search the following databases: Web of Science, Scopus, Compendex, CINAHL, Medline, IEEE Explore and Embase. Our search strategy has been developed with the assistance of the university library staff to accommodate the different syntactical requirements. The literature search will include the period between 2013 and 2023, and will be confined to articles published in English. We will exclude editorials, ongoing studies and working papers. The selection, extraction and analysis of the search data will be conducted using the 'Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for scoping reviews' system. The same system will also be used for the synthesis of the results. ETHICS AND DISSEMINATION: This scoping review does not require ethics approval as the review solely consists of peer-reviewed publications. The findings will be presented in peer-reviewed publications related to voice pathology.

Validity, reliability and reproducibility of the VLS parameters form for the collection of videolaryngostroboscopic basic findings.

OBJECTIVE: The videolaryngostroboscopy parameters form (VLSP form) is a diagnostic tool for the collection of videolaryngostroboscopic basic findings through the evaluation of 12 parameters. The aim of the present study is to preliminarily investigate intra- and inter-rater reliability, validity and responsiveness of the VLSP form. METHODS: A study on a total amount of 160 forms for the evaluation of VLS basic findings was carried out. 80 forms were scored through the VLSP form and 80 with the Voice Vibratory Assessment with Laryngeal Imaging (VALI) form Stroboscopy (S) by four expert phoniatricians, that blindly scored the VLS recordings of 5 subjects without voice disorders and 5 patients with organic voice disorder before and after successful phonosurgery. Intra-rater and inter-rater analysis have been performed for both forms. The scores obtained through VLSP form and VALI form S have been compared to analyse concurrent validity, while VLSP scores before and after phonosurgery have been compared to analyse responsiveness. Finally, each rater annotated the "difficulty" in rating every parameter and its "importance" for the diagnosis. RESULTS: The VLSP form showed good inter- and intra-rater reliability. It showed a good accuracy for the documentation of changes of laryngeal anatomy and function after phonosurgery, similarly to the VALI form S. The 12 parameters of the VLSP form were judged "Slightly Important" in 28.3% of the samples, "Very Important" in 64.8% of the samples, "Not Difficult" in 73.1% of the samples. CONCLUSIONS: The results of the present study suggest that the VLSP form is comparable to the VALI form S for the evaluation of videolaryngostroboscopic parameters and is a valid, reliable and reproducible diagnostic tool. It can help voice clinicians in the evaluation of VLS examinations and it allows for a punctual assessment of modifications in laryngeal anatomy and function in pathological conditions and after phonosurgery.

Voice use of nurses working in the intensive care unit during the COVID-19 pandemic.

OBJECTIVE: This study aimed to investigate the voice use of nurses working in intensive care units (ICUs) and their perception of acoustic environments. SETTING AND SAMPLE: The research was conducted in four different hospitals in China during the COVID-19 pandemic. A total of 60 ICU nurses were recruited for their voice use monitoring and 100 nurses participated in the survey. RESEARCH METHODOLOGY: Firstly, voice-related parameters such as voice level (SPL, dB), fundamental frequency (F0, Hz), and voicing time percentage (Dt, %) were measured using a vocal monitor. To collect data, a non-invasive accelerometer was attached to the participants' necks during their working hours. Secondly, the perception of the ICU acoustic environment was assessed using semantic differential. RESULTS: The results showed that nurses spoke approximately 0.9-4 dB louder to patients and colleagues in ICUs compared to quiet rooms, and their fundamental frequency (F0) significantly increased during work. The voice levels of nurses were influenced by background noise levels, with a significant correlation coefficient of 0.44 (p < 0.01). Furthermore, the background noise levels ranged from 58.1 to 73.9 dBA, exceeding the guideline values set by the World Health Organisation (WHO). The semantic differential analysis identified 'Stress' and 'Irritation' as the two main components, indicating the prevalence of negative experiences within ICUs. IMPLICATIONS FOR CLINICAL PRACTICE: This study highlights the potential risk of voice disorders among ICU nurses. The findings also underscore the importance of implementing strategies to reduce noise levels in ICUs to reduce voice disorders among nurses.

Self-perception of voice, hearing, and general health in screening for voice changes in older women. / Autopercepção da voz, audição e saúde geral no rastreio de distúrbio vocal em idosas.

PURPOSE: To verify the association between sociodemographic factors, vocal behavior, morbidities, and self-perception of voice, hearing, and general health in older women with voice disorders. METHODS: The sample had 95 older women aged 60 to 84 years (mean of 69,5). They were interviewed with a structured questionnaire on sociodemographic aspects, health, and vocal behavior. The Screening Protocol for Voice Disorders in Older Adults (RAVI) was used to identify the presence of voice disorders. RESULTS: Participants who had finished high school and were retired predominated. The number of older women with voice disorders according to RAVI was 46.3%. Physical sensations such as dry throat, throat clearing, and itchy throat were the most common complaints. The group of older women with voice disorders had worse self-perception of voice quality, hearing, and general health and a higher frequency of upper airway infections than those without voice disorders (p ≤ 0.05). CONCLUSION: The vocal self-assessment measured with RAVI was statistically associated with self-perception of voice quality, hearing, general health, sore throat, sinusitis, and respiratory allergies.

OBJETIVO: Verificar a associação de fatores sociodemográficos, do comportamento vocal, morbidades e autopercepção da voz, auditiva e de saúde geral de idosas com distúrbio vocal. MÉTODO: Participaram 95 idosas com idades entre 60 e 84 anos (média 69,5). Realizou-se uma entrevista com apoio de um questionário estruturado contendo questões sociodemográficas, de saúde e do comportamento vocal. Utilizou-se o Protocolo para Rastreamento de Alterações Vocais em Idosos (RAVI) para identificar a presença de distúrbio vocal. RESULTADOS: Houve o predomínio de participantes com ensino médio completo e aposentadas. O número de idosas que apresentaram distúrbio vocal segundo o RAVI foi de 46,3%. Queixas relacionadas às sensações físicas como garganta seca, pigarro e coceira na garganta foram as mais presentes. O grupo de idosas com distúrbio vocal apresentou pior autopercepção da qualidade vocal, audição, saúde geral e maior frequência de infecções de vias aéreas superiores quando comparadas àquelas sem distúrbio vocal (p≤0,05). CONCLUSÃO: Houve associação estatística entre a autoavaliação vocal mensurada pelo RAVI e a autopercepção da qualidade da voz, da audição, da saúde geral, inflamações de garganta, sinusite e alergias respiratórias.

Evaluation of quality and readability of internet information on voice disorders.

OBJECTIVES: The purpose of this study is to evaluate the readability and quality of Internet information related to vocal health, voice disorders and voice therapy. STUDY DESIGN: This is a cross-sectional study. METHODS: Eighty-two websites were included. Websites were then analyzed; their origin (clinic/hospital, non-profit, government), quality (Health On the Net [HON] certification and DISCERN scores) and readability (Atesman readability formula and Bezirci-Yilmaz new readability formula) were assessed. Statistical analysis was used to examine differences between website origin and quality and readability scores and correlations between readability instruments. RESULTS: Of the 82 websites, 93% were of private clinic/hospital, 6% were of non-profit organisation and 1% were of government. None of the 82 websites were HON certification, and the mean score of the item determining the general quality measure in DISCERN was 1.83 in a five-point scale. The mean of Atesman readability formula value was calculated as 50.46 (±8.16). This value is defined as 'moderately hard' according to the readability scale. The average of Bezirci-Yilmaz new readability formula value is 13.85 (±3.48). This value is defined as 13th and 14th grade. CONCLUSIONS: The quality of Internet-based health information about the voice is generally inadequate, and the sites examined in this study may be limited due to high readability levels. This may be a problem in people with poor literacy skills. For this reason, it is very important for speech and language therapists and other health professionals to evaluate and monitor the quality and readability of Internet-based information.

Do Adult Naïve Listeners Perceive Differences in Speech Before and After Therapy for Cleft Palate Speech Disorders? A Reliability Study of Perceptual Speech Ratings.

PURPOSE: This study compared the interrater reliability of adult naïve listeners' perceptual assessments of different speech variables in children with a cleft palate with or without a cleft lip (CP ± L). In addition, the study investigated whether the listeners were able to perceive differences in these speech variables before and after speech therapy for cleft palate speech disorders. METHOD: Thirty-four speech samples of 14 children with a CP ± L (14 samples collected immediately before 10 hr of speech intervention, 14 samples collected immediately after speech intervention, and six randomly selected samples that were duplicated to assess intrarater reliability) were perceptually assessed by 26 adult naïve listeners. The listening panel consisted of nine men and 17 women (age range: 18-51 years). The speech variables included speech understandability, speech acceptability, hypernasality, hyponasality, nasal airflow, and articulation, which were assessed on a visual analog scale. Furthermore, the need for speech therapy was assessed. RESULTS: Good to very good interrater reliability was observed for the naïve listeners' ratings of all speech variables. A significant time effect was found for the pre- and postevolution of the speech variables "speech understandability," "speech acceptability," "nasal airflow," and "articulation." This time effect indicates an improvement of these variables postintervention. According to the naïve listeners, children were less in need of additional speech therapy after the 10-hr intervention period compared to assessments before this intervention period. CONCLUSIONS: Adult naïve listeners perceptually identified an improvement in different speech variables after 10 hr of cleft palate speech therapy. These findings confirm previous assessments of expert speech-language pathologists and suggest that speech improvements after cleft palate speech therapy can also be perceived by communication partners outside the therapy room. Perceptual ratings of naïve listeners can, thus, be used to add life-situation significance to the assessments of experts. Future research could include both expert raters and caregivers or relatives of children with a CP ± L in listening panels, as previous knowledge on craniofacial anomalies may lead to different results.

Treatment efficacy of 532-nm diode laser glottoplasty in patients with sulcus vocalis: a prospective study.

PURPOSE: This study prospectively assessed the efficacy and safety of 532-nm diode laser glottoplasty in patients with sulcus vocalis. METHODS: A prospective human trial was performed from August 2016 to September 2021. 532-nm diode laser glottoplasty was performed in 30 consecutive patients with sulcus vocalis who suffered from voice problems. Patients underwent acoustic aerodynamic, perceptual, stroboscopic, and Voice Handicap Index-10 (VHI-10) evaluations before and 1, 6, and 12 months after laser glottoplasty. RESULTS: Most subjective parameters showed significant improvement (P < 0.05) at 6 months after laser glottoplasty and remained stable at 12 months. Most objective parameters showed significant improvement (P < 0.05) at 12 months after laser glottoplasty. Complications during follow-up included mild vocal fold vibration reduction in 3.3% of patients (1/30) and persistent vocal fold edema in 3.3% of patients (1/30). CONCLUSIONS: Statistically significant voice improvement at 12 months after 532-nm diode laser glottoplasty was achieved without serious complications.

Systematic Review of Literature on Vocal Demand Response: Understanding Physiology, Measurements, and Associated Factors.

PURPOSE: Considering the conceptual migration from vocal load and vocal loading to vocal demand and vocal demand response, this review of literature aimed to identify physiological explanations, reported measurements, and associated factors (vocal demands) reported in the literature when considering the phonatory response to a vocal demand. METHODS: A systematic review of literature, following the PRISMA Statement, was conducted using Web of Science, PubMed, Scopus, and ScienceDirect. Data were analyzed and presented in two parts. First, a bibliometric analysis, co-occurrence analysis, and content analysis were performed. Three criteria that got article inclusion were defined: (1) written in English, Spanish, and Portuguese; (2) published between 2009 and 2021; and (3) focused on vocal load and loading, vocal demand response, and voice assessment parameters. A total of 54 publications met the criteria and were included in this review. The second part included a conceptual framework based on the content analysis of three aspects of vocal demand response: (1) physiological explanations, (2) reported measurements, and (3) vocal demands. RESULTS AND CONCLUSION: As would be expected since vocal demand response is a relatively new term and not yet commonly used in literature when discussing way that the speakers respond to communicative scenarios, most of the studies reviewed (both historical and recent) still use the term of vocal load and vocal loading. Although there is a broad variety of literature discussing a wide range of vocal demands and voice parameters used to characterize the vocal demand response, results show that there is consistency across the studies. While vocal demand response is unique and intrinsic to the talker, associated factors that contribute to this response include both internal talker and external talker factors. Internal factors include muscle stiffness, viscosity in the phonatory system, vocal fold tissue damage, elevated sound pressure levels during occupational voice demands, extended periods of voice use, suboptimal body posture, difficulties in breathing technique, and sleep disturbances. Associated external factors include the working environment (noise, acoustics, temperature, humidity). In conclusion, although vocal demand response is intrinsic to the speaker, the speaker's response is affected by external vocal demands. However, due to the wide methods to evaluate vocal demand response, it has been difficult to establish its contribution to voice disorders in the general population and, specifically, among occupational voice users. This literature review identified commonly reported parameters and factors that may help clinicians and researchers define vocal demand response.

Biomechanical Parameters of Voice in Parkinson's Disease Patients.

INTRODUCTION: Previous research on voice in Parkinson's disease (PD) has consistently demonstrated alterations in acoustic parameters, including fundamental frequency (F0), maximum phonation time, Shimmer, and Jitter. However, investigations into acoustic parameter alterations in individuals with PD are limited. METHODS: We conducted an experimental study involving 20 PD patients (six women and fourteen men). Subjective measures of voice (VHI-30 scale and GRBAS) and objective measures using the OnlineLAB App tool for analyzing biomechanical correlates of voice were recorded. The app analyzed a total of 22 biomechanical parameters of voice. RESULTS: The results of subjective measures were consistent with findings from previous studies. However, the results of objective measures did not align with studies that employed acoustic measures. CONCLUSIONS: The biomechanical analysis revealed alterations in various parameters according to gender. These findings open up a new avenue of research in voice analysis for patients with PD, whether through acoustic or biomechanical analysis, aiming to determine whether the observed changes in these patients' voices are attributable to age or disease progression. This line of investigation will help elucidate the relative contribution of these factors to vocal alterations in PD patients and provide a more comprehensive understanding of the underlying mechanisms.

Prevalence of Voice Disorders in the United States: A National Survey.

OBJECTIVES: The prevalence of voice disorders has not been explored in the context of recent trends in voice use, including voice assistant technology and increased use of teleconferencing for remote work. The objective of this research is (1) to determine the prevalence of voice disorders in the adult population of the United States, and (2) to understand the association of voice disorders with demographic and voice use factors, including vocal demands, and use of teleconferencing and voice assistant technology. METHODS: A survey pertaining to voice disorders and voice use was developed and administered to a representative sample of US population. Demographics and information related to risk factors for voice disturbance, including high vocal demands, teleconferencing, and voice-assistant use were also analyzed. RESULTS: A total of 1522 responses were included. Of these, 20.6% reported having had a voice disorder at some point in their life. This rate was higher in employed respondents, singers, and teachers (all p < 0.0001) and was notably higher in those who used teleconferencing technology and voice assistant technology (both p < 0.0001). Approximately 60% of this subset reported seeking medical care for their voice, 12.6% reported a current voice disorder, and 9.5% reported a voice problem that had recurred multiple times. CONCLUSIONS: Approximately 1 in 5 Americans surveyed has had a voice disorder. Risk factors for voice disorders include use of teleconferencing technology, voice assistant use, and occupational factors. LEVEL OF EVIDENCE: 3 Laryngoscope, 134:347-352, 2024.

A Medicare Physician Fee Schedule Analysis of Reimbursement Trends in Laryngology from 2000 to 2021.

OBJECTIVE: The purpose of this study is to characterize Medicare reimbursement trends for laryngology procedures over the last two decades. METHODS: This analysis used CMS' Physician Fee Schedule (PFS) Look-Up Tool to determine the reimbursement rate of 48 common laryngology procedures, which were divided into four groups based on their practice setting and clinical use: office-based, airway, voice disorders, and dysphagia. The PFS reports the physician service reimbursement for "facilities" and global reimbursement for "non-facilities". The annual reimbursement rate for each procedure was averaged across all localities and adjusted for inflation. The compound annual growth rate (CAGR) of each procedure's reimbursement was determined, and a weighted average of the CAGR for each group of procedures was calculated using each procedure's 2020 Medicare Part B utilization. RESULTS: Reimbursement for laryngology procedure (CPT) codes has declined over the last two decades. In facilities, the weighted average CAGR for office-based procedures was -2.0%, for airway procedures was -2.2%, for voice disorders procedures was -1.4%, and for dysphagia procedures was -1.7%. In non-facilities, the weighted average CAGR for office-based procedures was -0.9%. The procedures in the other procedure groups did not have a corresponding non-facility reimbursement rate. CONCLUSION: Like other otolaryngology subspecialties, inflation-adjusted reimbursements for common laryngology procedures have decreased substantially over the past two decades. Because of the large number of physician participants and patient enrollees in the Medicare programs, increased awareness and further research into the implications of these trends on patient care is necessary to ensure quality in the delivery of laryngology care. LEVEL OF EVIDENCE: NA Laryngoscope, 134:247-256, 2024.

Vocal Problems and Burnout Syndrome in Nonuniversity Teachers in Galicia, Spain.

INTRODUCTION: Voice disorders and burnout syndrome are common among teachers. This study aimed to explore the relationship among vocal problems, burnout syndrome, and some personal work factors. METHODS: This cross-sectional descriptive study enrolled 90 nonuniversity teachers who completed the Multidimensional Vocal Scale for Teachers (EVM-D) to evaluate vocal problems and an adapted Spanish version of the Maslach Burnout Inventory-Educators Survey (MBI-ES) to detect burnout syndrome. RESULTS: Overall, 16% of teachers expressed symptoms compatible with burnout, and 60% of them were in the interval above the 75th percentile of the EVM-D, i.e., they had a high risk of vocal problems. An association between burnout and more vocal problems was established among teachers, particularly between the vocal symptoms and vocal abuse dimensions with the emotional exhaustion subscale of the MBI-ES. A history of anxiety/depression and fewer years of professional experience were associated with more vocal problems. The burnout group perceived more "loss of vocal power," "vocal fatigue," "vocal effort," and "hoarseness." Vocal abuse items received the highest scores of EVM-D. However, only "shouting" in the classroom was significantly different between the groups with and without burnout. CONCLUSION: Emotional exhaustion of burnout syndrome, history of anxiety/depression, and a shorter professional experience were associated with vocal problems, which could limit the performance of teachers. Reducing classroom noise, establishing strategies to avoid shouting, or strengthening personal accomplishments in teachers could be useful in breaking the cycle of vocal problems and emotional exhaustion, particularly at the beginning of their professional experience.

The Effects of Classroom Acoustic Conditions on Teachers' Health and Well-Being: A Scoping Review.

PURPOSE: Teachers spend a significant amount of time in classrooms, which can be noisy environments. The aim of this scoping review was to determine what is known from the literature about the effect of classroom acoustic conditions on teachers' health and well-being. METHOD: This scoping review followed the PRISMA-ScR (Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews) protocol. Four bibliographic databases were searched: ERIC, PubMed, Scopus, and Web of Science. RESULTS: Thirty-three articles were deemed relevant for the review. The most studied health aspect was teachers' vocal health. The majority of results showed higher noise levels or a higher number of students have a negative effect on teachers' health and well-being (61% and 60%, respectively), while 39% showed a negative effect of longer reverberation times. Most other results showed no effect. CONCLUSIONS: These results show that poor classroom acoustic conditions can have a negative effect on teachers' health and well-being. Therefore, creating classrooms with good acoustic conditions and controlling noise is vital. Limitations are discussed, and future research to better understand the relationship between classroom acoustic conditions and teachers' health and well-being is proposed. This future research will help in understanding the acoustic conditions that are needed to optimize teachers' health and well-being in the classroom.

Comparison of the efficacy and adverse effects of unilateral or bilateral botulinum toxin injections for adductor spasmodic dysphonia: a systematic review and meta-analysis.

PURPOSE: This study aims to aggregate and analyze existing clinical evidence to compare the efficacy and adverse effects of unilateral or bilateral botulinum toxin injections for the treatment of adductor spasmodic dysphonia (ADSD). METHODS: Reports from non-randomized controlled trials and cohort studies pertaining to the efficacy and adverse effects of unilateral and bilateral botulinum toxin injections for ADSD were identified and retrieved from four electronic databases from inception to July 2023. The meta-analysis employed fixed or random effects models to assess pooled relative risks (RR), mean differences (MDs), and standard mean differences (SMDs) with their corresponding 95% confidence intervals (CIs). RESULTS: We included two non-randomized controlled trials and seven cohort studies comprising 854 total patients. Meta-analysis of the included studies showed that bilateral botulinum toxin injections associated with a longer duration of vocal improvement (MD = - 2.89, 95% CI - 3.13 to - 2.65, I2 = 0%, P < 0.00001). However, bilateral botulinum toxin injections associated with an increase in adverse effects, including a longer duration of breathy voice quality (SMD = - 0.51, 95% CI - 0.79 to - 0.22, I2 = 35%, P = 0.0005) and a higher occurrence of swallowing difficulties (RR = 0.46, 95% CI 0.35 to 0.11, I2 = 0%, P < 0.00001). CONCLUSION: Bilateral botulinum toxin injections for ADSD showed a longer duration of vocal improvement, a longer breathy voice duration and a higher dysphagia occurrence and duration than unilateral injections.