Quantitative Evaluation of Video Laryngostroboscopy: Reliability of the Basic Parameters

Endoscopic Distance and its Impact on Quantified Age-related Vocal Fold Atrophy Measures

INTRODUCTION

The bowing index (BI) and normalized glottal gap area (NGGA) are used to quantify vocal fold morphology in ARVA; however, the influence of the distance between the flexible laryngoscope lens and the target area is not known. The goal is to test whether the endoscopic distance impacts vocal fold morphology measurements in patients with ARVA during flexible video laryngostroboscopy (VLS).

METHOD

Patients with ARVA who underwent VLS were included. Images were classified into near (close to the petiole of the epiglottis) and far (below nasopharynx, with tongue base and entire epiglottis visible) conditions. BI was calculated using a mobile application, and NGGA was measured using ImageJ.

RESULTS

This study included 23 patients; the mean age was 77 ± 7 years. Mean BI measured at the near distance was higher than far distances with a mean difference of 1.94 (95% CI: 0.92-2.96, p = 0.001). NGGA showed difference with changed distance -0.24 (95% CI: -0.48 to 0.01, p < 0.05).When stratifying patients into two groups based on median BI measurement, there was a statistically significant difference between near and far conditions, with increased BI in the near condition for patients above the median (p < 0.05), but no difference between the near and far condition for patients with BI below the median.

CONCLUSION

The BI and NGGA were impacted by the endoscopic distance during flexible VLS. BI was significantly higher in the near condition compared with the far condition. The difference in BI between the near and far conditions was more pronounced when the vocal fold bowing was greater. These findings call for heightened awareness of measurement discrepancies secondary to the endoscopic distance during flexible laryngostroboscopy.

LEVEL OF EVIDENCE

Level 2 Laryngoscope, 2024.

A Comparison of Voice and Psychotherapeutic Treatments for Adults With Functional Voice Disorders: A Systematic Review

OBJECTIVE

To examine the effect of traditional voice therapy and cognitive therapy on the voice and client-wellbeing outcomes in adults with functional voice disorders (FVD).

METHODS

A systematic review of English articles was conducted using Medline (Ovid), Embase (Elsevier), CINAHL (Ebsco), The Cochrane Central Register of Controlled Trials (CENTRAL), PsychInfo (Ebsco) and Speechbite from inception to current date. Additional studies were identified through bibliographies and authors were contacted when further information was required from an article. All study designs were included with pretest/posttest outcome measures related to voice. Independent extraction of studies was completed by three authors using predefined data fields and quality assessment tools.

RESULTS

Outcomes of 23 studies (2 RCTs and 21 cohort or case studies) are summarised using a narrative style due to heterogeneity of interventions and outcome scales used. Overall research quality of included studies was low, with many cohort and case studies lacking controls, blinding and robust outcome measures.

CONCLUSIONS

There are some benefits to pairing cognitive behavioural therapy (CBT) with traditional voice therapy for FVD including improved voice quality, psychosocial wellbeing and prevention of relapse. It is feasible to train speech-language pathologists (SLPs) in CBT-enhanced voice therapy. Further high-quality research is needed, however, to guide the clinical implementation of CBT for the management of FVD.

Consensus for voice quality assessment in clinical practice: guidelines of the European Laryngological Society and Union of the European Phoniatricians

INTRODUCTION

To update the European guidelines for the assessment of voice quality (VQ) in clinical practice.

METHODS

Nineteen laryngologists-phoniatricians of the European Laryngological Society (ELS) and the Union of the European Phoniatricians (UEP) participated to a modified Delphi process to propose statements about subjective and objective VQ assessments. Two anonymized voting rounds determined a consensus statement to be acceptable when 80% of experts agreed with a rating of at least 3/4. The statements with ≥ 3/4 score by 60-80% of experts were improved and resubmitted to voting until they were validated or rejected.

RESULTS

Of the 90 initial statements, 51 were validated after two voting rounds. A multidimensional set of minimal VQ evaluations was proposed and included: baseline VQ anamnesis (e.g., allergy, medical and surgical history, medication, addiction, singing practice, job, and posture), videolaryngostroboscopy (mucosal wave symmetry, amplitude, morphology, and movements), patient-reported VQ assessment (30- or 10-voice handicap index), perception (Grade, Roughness, Breathiness, Asthenia, and Strain), aerodynamics (maximum phonation time), acoustics (Mean F0, Jitter, Shimmer, and noise-to-harmonic ratio), and clinical instruments associated with voice comorbidities (reflux symptom score, reflux sign assessment, eating-assessment tool-10, and dysphagia handicap index). For perception, aerodynamics and acoustics, experts provided guidelines for the methods of measurement. Some additional VQ evaluations are proposed for voice professionals or patients with some laryngeal diseases.

CONCLUSION

The ELS-UEP consensus for VQ assessment provides clinical statements for the baseline and pre- to post-treatment evaluations of VQ and to improve collaborative research by adopting common and validated VQ evaluation approach.

Validation and enhancement of a vocal fold medial surface 3D reconstruction approach for in-vivo application

In laryngeal research, studying the vertical vocal fold oscillation component is often disregarded. However, vocal fold oscillation by its nature is a three-dimensional process. In the past, we have developed an in-vivo experimental protocol to reconstruct the full, three-dimensional vocal fold vibration. The goal of this study is to validate this 3D reconstruction method. We present an in-vivo canine hemilarynx setup using high-speed video recording and a right-angle prism for 3D reconstruction of vocal fold medial surface vibrations. The 3D surface is reconstructed from the split image provided by the prism. For validation, reconstruction error was calculated for objects located at a distance of up to 15 mm away from the prism. The influence of camera angle, changing calibrated volume, and calibration errors were determined. Overall average 3D reconstruction error is low and does not exceed 0.12 mm at 5 mm distance from the prism. Influence of a moderate (5°) and large (10°) deviation in camera angle led to a slight increase in error to 0.16 mm and 0.17 mm, respectively. This procedure is robust towards changes in calibration volume and small calibration errors. This makes this 3D reconstruction approach a useful tool for the reconstruction of accessible and moving tissue surfaces.

Quantification of Vocal Fold Atrophy in Age‐Related and Parkinson's Disease‐Related Vocal Atrophy

OBJECTIVE

Vocal fold atrophy (VFA) is associated with aging and Parkinson's disease (PD). Clinical diagnosis of VFA depends on several visual-perceptual laryngostroboscopy findings that are inherently subjective. The purpose of this study was to use quantitative measurements to; (1) examine the relationships between VFA and dysphonia severity and (2) evaluate differences in VFA in patients with age-related VFA versus PD.

METHODS

Thirty-six patients >60 years of age with VFA were included in this retrospective cohort study. Demographic information, medical history, Consensus Auditory-Perceptual Evaluation of Voice (CAPE-V), Voice Handicap Index-10 (VHI-10), and still images from the stroboscopic exam were obtained. Image J™ was used to measure VFA, including bowing index (BI), normalized glottal gap area, and normalized mucosal wave amplitude. Pearson's correlation was used to evaluate the relationship between VFA, CAPE-V, and VHI-10. t-Tests and multivariate linear regression were used to compare VFA measures by dysphonia severity (CAPE-V <30 vs. >30) and diagnosis (age-related vocal atrophy [ARVA] and PD).

RESULTS

BI was positively correlated with CAPE-V. Patients with CAPE-V >30 had a significantly larger BI compared to those with CAPE-V <30. Patients with PD had significantly larger BI than those with ARVA. Diagnosis of PD also predicted a larger BI after controlling for age and CAPE-V.

CONCLUSION

Quantitative measures supported an association between bowing severity and dysphonia severity in patients with PD and ARVA. A PD diagnosis significantly predicted more severe BI. These findings demonstrate the potential utility of BI. Quantitative VFA measures might also provide insight into the mechanisms of ARVA and dysphonia.

LEVEL OF EVIDENCE

3 Laryngoscope, 133:1462-1469, 2023.

Interdependencies between acoustic and high-speed videoendoscopy parameters

In voice research, uncovering relations between the oscillating vocal folds, being the sound source of phonation, and the resulting perceived acoustic signal are of great interest. This is especially the case in the context of voice disorders, such as functional dysphonia (FD). We investigated 250 high-speed videoendoscopy (HSV) recordings with simultaneously recorded acoustic signals (124 healthy females, 60 FD females, 44 healthy males, 22 FD males). 35 glottal area waveform (GAW) parameters and 14 acoustic parameters were calculated for each recording. Linear and non-linear relations between GAW and acoustic parameters were investigated using Pearson correlation coefficients (PCC) and distance correlation coefficients (DCC). Further, norm values for parameters obtained from 250 ms long sustained phonation data (vowel /i/) were provided. 26 PCCs in females (5.3%) and 8 in males (1.6%) were found to be statistically significant (|corr.| ≥ 0.3). Only minor differences were found between PCCs and DCCs, indicating presence of weak non-linear dependencies between parameters. Fundamental frequency was involved in the majority of all relevant PCCs between GAW and acoustic parameters (19 in females and 7 in males). The most distinct difference between correlations in females and males was found for the parameter Period Variability Index. The study shows only weak relations between investigated acoustic and GAW-parameters. This indicates that the reduction of the complex 3D glottal dynamics to the 1D-GAW may erase laryngeal dynamic characteristics that are reflected within the acoustic signal. Hence, other GAW parameters, 2D-, 3D-laryngeal dynamics and vocal tract parameters should be further investigated towards potential correlations to the acoustic signal.

Machine learning based identification of relevant parameters for functional voice disorders derived from endoscopic high-speed recordings

In voice research and clinical assessment, many objective parameters are in use. However, there is no commonly used set of parameters that reflect certain voice disorders, such as functional dysphonia (FD); i.e. disorders with no visible anatomical changes. Hence, 358 high-speed videoendoscopy (HSV) recordings (159 normal females (N_F), 101 FD females (FD_F), 66 normal males (N_M), 32 FD males (FD_M)) were analyzed. We investigated 91 quantitative HSV parameters towards their significance. First, 25 highly correlated parameters were discarded. Second, further 54 parameters were discarded by using a LogitBoost decision stumps approach. This yielded a subset of 12 parameters sufficient to reflect functional dysphonia. These parameters separated groups N_F vs. FD_F and N_M vs. FD_M with fair accuracy of 0.745 or 0.768, respectively. Parameters solely computed from the changing glottal area waveform (1D-function called GAW) between the vocal folds were less important than parameters describing the oscillation characteristics along the vocal folds (2D-function called Phonovibrogram). Regularity of GAW phases and peak shape, harmonic structure and Phonovibrogram-based vocal fold open and closing angles were mainly important. This study showed the high degree of redundancy of HSV-voice-parameters but also affirms the need of multidimensional based assessment of clinical data.

Determination of Clinical Parameters Sensitive to Functional Voice Disorders Applying Boosted Decision Stumps

BACKGROUND

Various voice assessment tools, such as questionnaires and aerodynamic voice characteristics, can be used to assess vocal function of individuals. However, not much is known about the best combinations of these parameters in identification of functional dysphonia in clinical settings.

METHODS

This study investigated six scores from clinically commonly used questionnaires and seven acoustic parameters. 514 females and 277 males were analyzed. The subjects were divided into three groups: one healthy group (N01) (49 females, 50 males) and two disordered groups with perceptually hoarse (FD23) (220 females, 96 males) and perceptually not hoarse (FD01) (245 females, 131 males) sounding voices. A tree stumps Adaboost approach was applied to find the subset of parameters that best separates the groups. Subsequently, it was determined if this parameter subset reflects treatment outcome for 120 female and 51 male patients by pairwise pre- and post-treatment comparisons of parameters.

RESULTS

The questionnaire "Voice-related-quality-of-Life" and three objective parameters ("maximum fundamental frequency", "maximum Intensity" and "Jitter Percent") were sufficient to separate the groups (accuracy ranging from 0.690 (FD01 vs. FD23, females) to 0.961 (N01 vs. FD23, females)). Our study suggests that a reduced parameter subset (4 out of 13) is sufficient to separate these three groups. All parameters reflected treatment outcome for patients with hoarse voices, Voice-related-quality-of-Life showed improvement for the not hoarse group (FD01).

CONCLUSION

Results show that single parameters are insufficient to separate voice disorders but a set of several well-chosen parameters is. These findings will help to optimize and reduce clinical assessment time.

Value of pre- and intraoperative diagnostic methods in suspected glottic neoplasia

PURPOSE

To evaluate the individual and combined ability of videostroboscopy (VS), high-speed digital imaging (HSDI), enhanced endoscopy (EE) and saline infusion (SI) to predict neoplasia, defined as glottic precursor lesion (GPL) or T1a glottic cancer, in patients suspected for glottic neoplasia.

METHODS

A nationwide prospective cohort study of patients treated by cordectomy for suspected GPL or T1a glottic cancer from August 1st 2016 to October 31st 2018 was conducted in the five Danish University Departments of Head and Neck surgery. Sensitivity, specificity, negative and positive predictive values, and area under Receiver Operating Curves (AUC-ROC) were calculated with 95% confidence intervals with respect to the histological diagnosis. Logistic regression with an imputation model for missing data was applied.

RESULTS

261 patients aged 34-91 years participated; 79 (30.3%) with non-neoplasia (i.e., inflammation, papilloma, hyperkeratosis) and 182 (69.7%) neoplasia, hereof 95 (36.4%) with GPL and 87 (33.3%) with T1a glottic cancer. Data from 188 VS, 60 HSDI, 100 preoperative EE, 209 intraoperative EE, and 234 SI were analyzed. In the complete case analysis the AUC-ROC of each diagnostic test was low, but increased when the tests were combined and especially if the combination included EE. However, multinomial logistic regression with imputation showed significant association (p < 0.05) only between age, male gender, and perpendicular vasculature in intraoperative EE, and the endpoint neoplasia.

CONCLUSIONS

Intraoperative EE was the most accurate diagnostic method in detecting neoplasia. The prediction ability of methods applied preoperatively was more limited, but improved when test modalities were combined.

Assessment of Clinical and Social Characteristics That Distinguish Presbylaryngis From Pathologic Presbyphonia in Elderly Individuals

Importance

An aging population experiences an increase in age-related problems, such as presbyphonia. The causes of pathologic presbyphonia are incompletely understood.

Objective

To determine what distinguishes pathologic presbyphonia from presbylaryngis.

Design, Setting, and Participants

This was a cohort study at an outpatient otolaryngology subspecialty clinic of a tertiary academic referral center. Participants were consecutive consenting adults older than 74 years without laryngeal pathologic abnormalities who visited the clinic as participants or companions. Patient questionnaires, otolaryngologic, video stroboscopic, and voice examinations were compiled. Patients were divided into groups based on whether they endorsed a voice complaint. Three blinded authors graded stroboscopic examinations for findings consistent with presbylaryngis (vocal fold bowing, vocal process prominence, glottic insufficiency).

Main Outcomes and Measures

Voice Handicap Index-10, Reflux Symptom Index, Cough Severity Index, Dyspnea Index, Singing Voice Handicap Index-10 , Eating Assessment Tool -10, Voice-Related Quality of Life (VRQOL), and Short-Form Health Survey; face-sheet addressing social situation, work, marital status, education, voice use, transportation; acoustic and aerodynamic measures; and a full otolaryngologic examination, including videostroboscopic imaging.

Results

A total of 31 participants with dysphonia (21 were female; their mean age was 83 years [range, 75-97 years]) and 26 control participants (16 were female; their mean age was 81 years [range, 75-103 years]) completed the study. Presbylaryngis was visible in 27 patients with dysphonia (87%) and 22 controls (85%). VHI-10 and VRQOL scores were worse in patients with pathologic presbyphonia (median [range] VHI-10 scores, 15 (0-40) vs 0 (0-16) and median VRQOL score, 19 [0-43] vs 10 [10-23]). All other survey results were indistinguishable, and no social differences were elucidated. Acoustic measures revealed that both groups averaged lower than normal speaking fundamental frequency (mean [SD], 150.01 [36.23] vs 150.85 [38.00]). Jitter was 3.44% (95% CI, 2.46%-4.61%) for pathologic presbyphonia and 1.74% (95% CI, 1.35%-2.14%) for controls (d = 0.75). Shimmer means (95% CI) were 7.8 2 (6.08-10.06) for the pathologic presbyphonia group and 4.84 (3.94-5.72) for controls (d = 0.69). Aerodynamic measures revealed an odds ratio of 3.03 (95% CI, 0.83-11.04) for patients with a maximum phonation time of less than 12 seconds who had complaints about dysphonia.

Conclusions and Relevance

Presbylaryngis is present in most ambulatory people older than 74 years. Some will endorse pathologic presbyphonia that has a negative effect on their voice and quality of life. Pathologic presbyphonia seems to be influenced by respiratory capacity and sex. Further study is required to isolate other social, physiologic, and general health characteristics that contribute to pathologic presbyphonia.

Influence of spatial camera resolution in high-speed videoendoscopy on laryngeal parameters

In laryngeal high-speed videoendoscopy (HSV) the area between the vibrating vocal folds during phonation is of interest, being referred to as glottal area waveform (GAW). Varying camera resolution may influence parameters computed on the GAW and hence hinder the comparability between examinations. This study investigates the influence of spatial camera resolution on quantitative vocal fold vibratory function parameters obtained from the GAW. In total 40 HSV recordings during sustained phonation (20 healthy males and 20 healthy females) were investigated. A clinically used Photron Fastcam MC2 camera with a frame rate of 4000 fps and a spatial resolution of 512×256 pixels was applied. This initial resolution was reduced by pixel averaging to (1) a resolution of 256×128 and (2) to a resolution of 128×64 pixels, yielding three sets of recordings. The GAW was extracted and in total 50 vocal fold vibratory parameters representing different features of the GAW were computed. Statistical analyses using SPSS Statistics, version 21, was performed. 15 Parameters showing strong mathematical dependencies with other parameters were excluded from the main analysis but are given in the Supporting Information. Data analysis revealed clear influence of spatial resolution on GAW parameters. Fundamental period measures and period perturbation measures were the least affected. Amplitude perturbation measures and mechanical measures were most strongly influenced. Most glottal dynamic characteristics and symmetry measures deviated significantly. Most energy perturbation measures changed significantly in males but were mostly unaffected in females. In females 18 of 35 remaining parameters (51%) and in males 22 parameters (63%) changed significantly between spatial resolutions. This work represents the first step in studying the impact of video resolution on quantitative HSV parameters. Clear influences of spatial camera resolution on computed parameters were found. The study results suggest avoiding the use of the most strongly affected parameters. Further, the use of cameras with high resolution is recommended to analyze GAW measures in HSV data.

Systematic review of the diagnostic value of laryngeal stroboscopy in excluding early glottic carcinoma

OBJECTIVE

Laryngeal stroboscopy is an important diagnostic tool in the work-up of patients with phoniatric complaints. The aim of this article was to evaluate the diagnostic value of laryngeal stroboscopy in excluding glottic carcinoma in patients with suspected glottic carcinoma.

DATA SOURCES

PubMed, Embase and the Cochrane Library.

REVIEW METHODS

A systematic literature search was performed in PubMed, Embase and the Cochrane Library. Studies reporting original study data were included. Studies were selected based on predefined inclusion and exclusion criteria and were consequently systematically assessed for their relevance and risk of bias. Studies with low relevance, high risk of bias or both were excluded from analysis. The prevalences, sensitivities, specificities and post-test probabilities of laryngeal stroboscopy for detecting glottic carcinoma were extracted or calculated with data supplied in the articles.

RESULTS

Seven studies, with high relevance and moderate risk of bias, were selected for data extraction. The baseline risk of glottic carcinoma was 25-49% in the included studies. Sensitivity ranged between 80% and 100% and specificity between 25% and 100%. Post-test probabilities of malignancy in case of an abnormal stroboscopy ranged between 35% and 100%. Post-test probabilities of malignancy in case of a normal stroboscopy ranged between 0% and 29%.

CONCLUSION

A normal laryngeal stroboscopic result predicts the absence of invasive carcinoma. Laryngeal stroboscopy can therefore be suggested as a useful supplemental examination in the standard diagnostic work-up for all patients with suspected glottic carcinoma.