A Cepstral Analysis of Pathological Voice Quality in the Korean Population using Praat.

OBJECTIVES: This study aimed to investigate the reference values for cepstral peak prominence (CPP) and smoothed CPP (CPPS) measured using Praat in Korean speakers with the normal, healthy and pathological voice. METHODS: A total of 4,524 Korean participants with vocally healthy (n = 410) and dysphonic voices (n = 4,114) participated in this study. The speech task consisted of a sustained vowel /a/ and a sentence reading the Korean passage "Walk". CPP and CPPS values were quickly and automatically measured in sustained vowel and continuous speech tasks using Praat script. Furthermore, three veteran speech language pathologists (SLPs) scored the severity of dysphonia using the GRBAS scale (grade, roughness, breathiness, asthenia, strain) and Consensus Auditory Perceptual Evaluation of Voice (CAPE-V). RESULTS: Three SLPs showed high inter- and intra-rater reliabilities (IRR) in auditory-perceptual (A-P) evaluation. Significant differences were confirmed in CPP and CPPS between the normally healthy and pathological voice groups for both voice tasks (P < 0.01). The measured values of CPP and CPPS varied depending on the laryngeal pathology. In the receiver operating characteristic (ROC) curve analysis, the CPP_Vowel (CPP_V), CPPS_V, CPP_Sentence (CPP_S), and CPPS_S cut-off values were <21.5, <12.0, <19.7, and <10.1, respectively. Through ROC curve analysis, it was confirmed that CPP and CPPS had excellent diagnostic accuracy in distinguishing disordered voice (area under the ROC: 0.951-0.966). CONCLUSION: We investigated the reference values for CPP and CPPS measured with Praat for Korean speakers and confirmed that cepstral analysis is a promising tool for differentiating pathological voice.

Clinical Significance of the Preoperative Thyroidectomy-Related Voice Questionnaire Score in Thyroid Surgery.

BACKGROUND: The thyroidectomy-related voice questionnaire (TVQ) is an efficient screening tool for detecting postoperative vocal dysfunction. The aim of this study was to confirm the significance of the preoperative TVQ score in thyroid surgery. METHODS: We examined 180 women who underwent total thyroidectomy with central lymph node dissection from March 2014 to May 2016. Based on the preoperative TVQ score, participants were categorized under "normal" (TVQ score <5) and "abnormal" (TVQ score ≥5) groups. The laryngoscopic examination and acoustic analysis were performed and the TVQ score assessed before and after surgery (2 weeks, 2 months, and 8 months). RESULTS: In the normal group, the TVQ score increased up to 2 months postoperatively and had decreased at 8 months postoperatively but was significantly higher than the preoperative TVQ score. In the abnormal group, the TVQ score increased up to 2 months postoperatively but had recovered similar to the preoperative TVQ score 8 months postoperatively. The preoperative TVQ score in the abnormal group moderately correlated with the final TVQ score; however, the preoperative TVQ score in the normal group did not correlate with the TVQ score 8 months postoperatively. CONCLUSION: During preoperative patient counseling, it is important to explain that voice changes without vocal cord palsy may occur postoperatively and that it may take a long time to resolve, particularly in patients with a normal preoperative TVQ score.

Validation of Acoustic Voice Quality Index Version 3.01 and Acoustic Breathiness Index in Korean Population.

OBJECTIVES: This study aimed to verify the Acoustic Voice Quality Index (AVQI) version 3.01 and the Acoustic Breathiness Index (ABI) as tools for acoustic analyses in the Korean language. METHODS: Concatenated voice samples of sustained vowels (SV) and continuous speech (CS) were collected from 151 subjects with dysphonia and 71 vocally healthy subjects. The overall voice disorder severity (grade [G] and overall severity [OS]) and breathiness severity (B) were subjected to an auditory-perceptual rating by three raters. First, we equalized the proportions of SV and CS with respect to the time lengths of the voice samples to improve the ecological validity. We then validated the AVQI and ABI in the Korean language, using our most recent dataset of 1,667 voice samples. Second, we compared the results of the acoustic analyses between the vocally healthy controls and the dysphonia groups. Third, we confirmed the concurrent validity and diagnostic accuracy using the Spearman rank-order correlation coefficient (rs) and various statistical methods (receiver operating characteristic curve, pairwise comparison, and likelihood ratio [LR] analyses). RESULTS: We observed strong inter-rater reliability for G, B, and OS. Moreover, we identified 26 standardized syllables in the CS samples (3 second voiced segments), which allowed the equalization of both voice tasks. A comparison of the two voice groups revealed statistically significant differences in the AVQI, ABI, G, B, and OS (all P < 0.01). Moreover, we identified strong correlations of the AVQI with G (rs > 0.88, P < 0.01) and OS (rs > 0.84, P < 0.01) and of ABI with B (rs > 0.87, P < 0.01). Finally, we confirmed cutoffs of 3.154 (sensitivity: 90%, specificity: 89%, LR+: 8.45, and LR-: 0.12) and 3.685 (sensitivity: 88%, specificity: 86%, LR+: 6.47, and LR-: 0.14) as optimal predictive powers for AVQI and ABI, respectively. CONCLUSION: As per our results, in a sample of Korean speakers, the AVQI and ABI exhibited strong concurrent validity for the quantification of dysphonia severity with respect to OS and B. We consider that analyses based on the AVQI and ABI will enable the discrimination and assessment of dysphonia in clinical practice.

Korean Voice Catastrophization Index (K-VCI): Validation of the Voice Catastrophization Index for Koreans.

OBJECTIVE: The purpose of present study was to validate a Korean version of the Voice Catastrophization Index for assessing catastrophization in patients with voice problems in a Korean population. METHODS: Case group patients with voice problems (n = 80) and control group patients without voice problems (n = 25) participated in the study. They were asked to complete three questionnaires: Korean Voice Handicap Index, Korean Voice-Related Quality of Life, and Korean Voice Catastrophization Index (K-VCI). Some of case group with voice problems completed the same three questionnaires again to assess test-retest reliability. Clinicians implemented the Consensus Auditory-Perceptual Evaluation of Voice evaluation to rate the overall severity on voice quality. RESULTS: K-VCI scores for case group were significantly higher than those for control group. K-VCI scores were significantly correlated with Korean Voice Handicap Index, Korean Voice-Related Quality of Life, and overall severity. The K-VCI had significant test-retest reliability and its internal consistency was good to excellent (range of Cronbach alpha correlation coefficients: 0.789-0.930). The K-VCI was not affected by patient sex, age, symptom duration, or diagnosis types. K-VCI scores were highest among patients with primary muscle tension dysphonia. CONCLUSION: We validated the K-VCI questionnaire for use in measuring the degree of catastrophization of voice problems in a Korean population. Future studies with a larger sample size will be necessary to further verify this and determine the clinical usefulness of the K-VCI.

Comparison of Cepstral Analysis Based on Voiced-Segment Extraction and Voice Tasks for Discriminating Dysphonic and Normophonic Korean Speakers.

OBJECTIVES: This study investigated whether there are differences in the discriminatory power of cepstral analysis according to the voiced-segment extraction method and voice tasks used for identifying dysphonic and normophonic Korean individuals. MATERIALS AND METHODS: A total of 2,863 subjects (2,595 subjects with and 268 subjects without dysphonia) were included in this study. The 3-second sustained vowel (SV) /a/ and one sentence of "Sanchaek" were edited and analyzed using Praat scripts. Cepstral analyses (cepstral peak prominence [CPP], smoothed cepstral peak prominence [CPPS], and low/high spectral ratio [LHRatio]) were performed using three voice tasks, namely, SV, continuous speech (CS), and extracted continuous speech (EXT) samples. Additionally, auditory-perceptual (A-P) assessments were performed by three speech language pathologists. RESULTS: Significant differences were found between dysphonic and normophonic voice groups for all cepstral parameters, except the LHRatio_EXT. Cepstral measurements of both SV and CS were highly correlated with A-P ratings. Furthermore, the diagnostic predictive power of CPP and CPPS for CS using the area under the receiver operating characteristic curve (AUC) was >0.919, the positive likelihood ratio (LR+) was ≥6.85, and the negative likelihood ratio (LR-) was ≤0.23. Additionally, for EXT, the AUC was >0.816, LR+ was 3.10, and LR- was ≤0.33. CONCLUSION: Both CS and EXT can predict dysphonia relatively well (r > 0.816). EXT showed lower predictability than the original sample (CS) analysis. Subsequent studies should implement voiced-segment extraction methods using various algorithms.

The validity of the Acoustic Breathiness Index in the evaluation of breathy voice quality: A Meta-Analysis.

BACKGROUND: The evaluation of voice quality with acoustic measurements is useful to objectify the diagnostic process. Particularly, breathiness was highly evaluated and the Acoustic Breathiness Index (ABI) might have promising features. OBJECTIVE OF REVIEW: The goal of the present meta-analysis is to quantify, from existing cross-validation studies, the evidence for the diagnostic accuracy of ABI, including its sensitivity and specificity. TYPE OF REVIEW: Meta-analysis. SEARCH STRATEGY: We searched in MEDLINE, Google Scholar and Science Citation Index, and as manual search for the term Acoustic Breathiness Index from inception to February 2020. Studies were included that used equal proportion of continuous speech and sustained vowel segments, a recording hardware with a sufficient standard for voice signal analyses, the software Praat for signal processing and the customised Praat script, and two groups of subjects (vocally healthy and voice-disordered). Furthermore, the diagnostic accuracy of ABI was measured. EVALUATION METHOD: The primary outcome variable was ABI. The score ranged from 0 to 10 with varying thresholds according to different languages to determine the absence or presence of breathiness. A meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses of diagnostic test accuracy study guidelines. Data were extracted, and the risk of bias was assessed using the QUADAS-2 tool. The pooled sensitivity and specificity of ABI were determined using a summary receiver operating characteristic (SROC) approach to calculate also a weighted threshold value of ABI with its sensitivity and specificity. RESULTS: A total of 34 unique citations were screened, and 10 full-text articles were reviewed, including six studies. In total, 3603 voice samples were considered for further analysis separating into 467 vocally healthy and 3136 voice-disordered voice samples. The pooled sensitivity was 0.84 (95% CI, 0.83-0.85), and the pooled specificity was 0.92 (95% CI, 0.89-0.94). The area under the curve of the SROC curve of this analysis showed an excellent value of 0.94. The weighted ABI threshold was determined at 3.40 (sensitivity: 0.86, 95% CI, 0.84-0.87.; specificity: 0.90, 95% CI 0.88-0.92). CONCLUSIONS: The results confirm the ABI as robust and valid objective measure for evaluating breathiness.

Comparison of Two Versions of the Acoustic Voice Quality Index for Quantification of Dysphonia Severity.

OBJECTIVES: The acoustic voice quality index (AVQI) is a specific acoustic indicator designed to objectively estimate dysphonia severity and measure the values of acoustic parameters based on the diagnostic category. This study compared the performance of two AVQI versions (2.02 and 3.01, v2 and v3) and PraatCPPS using a voice sample of Korean population. MATERIALS AND METHODS: Voice samples for sustained vowel and connected speech were elicited from 2257 patients across 14 diagnostic categories. Auditory-perceptual (A-P) assessments of dysphonia severity were compared to acoustic parameters of severity derived from two versions of the AVQI (v2 and v3) as well as the PraatCPPS. RESULTS: The AVQI-estimated severity (v2 and v3) and PraatCPPS severity for concatenated voice samples strongly correlated with each other and were significantly associated with A-P ratings. The AVQI (v2 and v3) and PraatCPPS showed high reliability in differentiating between pathological voice disorders. CONCLUSION: The AVQI (v2 and v3) and PraatCPPS were strongly correlated with the A-P ratings and provided valid estimates of dysphonia severity. However, the associations of the A-P ratings with the AVQIv2 were significantly stronger than those with the AVQIv3 and PraatCPPS, suggesting that the V2 outperformed the V3 and PraatCPPS.

Voice Recovery in a Patient with Inhaled Laryngeal Burns.

INTRODUCTION: Laryngeal burns cause long-term voice disorders due to mucosal changes of the vocal folds. Inhalation injuries affect voice production and result in changes in the mucosal thickness and voice quality. CASE REPORT: A 47-year-old woman was transferred to our department with laryngeal burns sustained during a house fire. On laryngoscopic examination, mucosal waves of both vocal folds were not visualized due to the injury caused by inhalation of high-temperature toxic smoke. Hence, voice analysis, laryngoscopic examinations, and high-speed videoendoscopy (HSV) were performed to evaluate vocal fold vibrations. An absence of mucosal waves and a breathy and strained voice with a severe grade were noted. We report that voice quality was recovered to close to the normal state through multiple treatments such as medication, voice therapy, and counseling. CONCLUSION: This paper presents the unique case of a patient with laryngeal burns, in which vibrations of the vocal folds were observed using laryngoscopic examination and HSV. Voice samples before and after treatment were also analyzed. By observing the vibration pattern of the injured vocal fold, it is expected that appropriate diagnosis and treatment planning can be established in clinical practice.

Validation of the Acoustic Voice Quality Index in the Korean Language.

OBJECTIVE: The purpose of this study was to explore the concurrent validity of the Acoustic Voice Quality Index (AVQI) in a Korean population. We investigated the feasibility of its cutoff values and diagnostic accuracy in discriminating between normal and dysphonic voices. MATERIALS AND METHODS: A total of 1,524 native Korean subjects with normal voices (n = 113) and with voice disorders (n = 1,411) were asked to speak and sustain the vowel "a" and to read the Korean text "Walk" aloud. A 2-second mid-speech portion of the sustained vowel sound and two sentences (with 26 syllables) were edited and concatenated, and the AVQI was calculated. Additionally, two auditory-perceptual assessments, namely the Grade, Roughness, Breathiness, Asthenia, Strain scale, and the Consensus Auditory-Perceptual Evaluation of Voice were used by five speech language pathologists to rate the severity of dysphonia. RESULTS: Both auditory-perceptual assessments showed high confidence levels among the five speech language pathologists. The AVQI correlated with grade (G) and overall severity (OS). There were statistically significant differences in AVQI, G, and OS between normal and pathological speech groups. In the receiver operating characteristic curve analysis, AVQI, G, and OS cutoff values were <3.33, <0.00, and <22.00, respectively. The receiver operating characteristic curve analysis indicated that AVQI had excellent diagnostic accuracy for discriminating between normal and dysphonic voices (area under the curve: 0.970-0.977). CONCLUSIONS: We demonstrated the concurrent validity of AVQI as a promising tool for assessing overall voice quality and quantifying dysphonia in a Korean-speaking population.

Usefulness of Two-Dimensional Digital Kymography in Patients With Vocal Fold Scarring.

OBJECTIVE: Although laryngeal videostroboscopy is widely utilized in the analysis of vocal fold vibrations, it is often difficult to identify patterns of vocal fold vibrations in patients with aperiodic voice signals due to failure of synchronization during laryngeal videostroboscopy examination. Therefore, the present study aimed to compare the usefulness of simultaneous two-dimensional digital kymography (2D DKG) and traditional DKG for the detection of changes in the pattern of vocal fold vibrations in patients with vocal fold scarring (VFS). METHODS: Seven patients with VFS and one normal subject underwent high-speed videoendoscopy (HSV). DKG and 2D DKG evaluations of vocal fold vibrations were performed simultaneously, following which both qualitative and quantitative analyses were performed. RESULTS: Simultaneous DKG and 2D DKG enabled observation of vibratory patterns as well as amplitude and phase symmetry. DKG revealed and provided temporal information regarding the pattern of vocal fold vibrations at sites of VFS. In contrast, 2D DKG provided real-time information regarding the pattern of vibrations for the whole vocal fold region and regions of increased stiffness, as well as spatial information regarding changes in this pattern. CONCLUSION: Our findings indicate that 2D DKG enables the assessment of overall vocal fold vibrations, regardless of periodicity, and that simultaneous DKG and 2D DKG can be used to confirm abnormal patterns of vocal fold vibrations in patients with impaired flexibility and elasticity of the vocal folds.

Effects of Injection Laryngoplasty with Hyaluronic Acid in Patients with Vocal Fold Paralysis.

OBJECTIVES: The purpose of this study was to explore the effects of injection laryngoplasty (IL) with hyaluronic acid in patients with vocal fold paralysis (VFP). METHODS: A total of 50 patients with VFP participated in this study. Pre- and post-IL assessments were performed, which included analyzing the sustained vowel /a/ phonation, and the patient reading 1 Korean sentence from the "Walk" passage that comprised 25 syllables in 10 words. To investigate the effect of IL on vocal fold function, acoustic analysis (acoustic voice quality index, cepstral peak prominence, maximum phonation time, speaking fundamental frequency) was conducted and auditory-perceptual (grade and overall severity), visual judgment (gap), and self-questionnaire (voice handicap index-10) assessments were performed. RESULTS: The patients with VFP showed statistically significant differences between pre-and post-IL assessments for acoustic and auditory-perception, visual judgment, and self-questionnaire assessments. CONCLUSION: The patients with VFP showed positive change in vocal fold function between pre- and post-IL measurements. The findings showed that IL with hyaluronic acid is an effective method to improve vocal fold function in patients with VFP.

The cut-off analysis using visual analogue scale and cepstral assessments on severity of voice disorder.

Purpose: The aims of this study were to: (1) determine the visual analogue scale (VAS) and cepstrum peak prominence (CPP) cut-off points on the ratings of numerical scale (NS) related to the severity of voice disorder ratings and (2) verify the discriminative power of these cut-off points for distinguishing between different severities of voice disorder. Methods: Auditory-perceptual severity assessments (VAS and four-point NS) of 214 voice samples were performed by three speech-language pathologists and CPP parameters were used for the acoustic analysis. Both VAS and CPP cut-off points were obtained using receiver operating characteristic (ROC) curve analyses, based on their correspondence with NS ratings. Results: A high level of inter- and intra-rater reliability was found for the auditory-perceptual assessments of both VAS and NS. The VAS cut-off points for overall severity (OS), between normal variation and mild/moderate severity, mild/moderate and moderate severity, and moderate and severe severity were 32.7, 51.7, and 71.7 points, respectively, and CPP cut-off points were 7.050, 4.651, and 2.989 points, respectively. Areas under the ROC curves demonstrated excellent specificity and sensitivity of all cut-off points. Conclusions: The VAS and CPP cut-off points of OS of voice disorder demonstrated a high power to discriminate between different severities of voice disorder. The results of this study suggested cut-off points for clinical use.

Real-time dual visualization of two different modalities for the evaluation of vocal fold vibration - Laryngeal videoendoscopy and 2D scanning videokymography: Preliminary report.

OBJECTIVE: Currently, various tools have been introduced for the assessment of vocal fold vibration: laryngeal videolaryngoscopy (LV), videokymography (VKG), high speed videoendoscopy (HSV), digital videokymography (DKG), and 2D scanning videokymography (2D VKG). Among these, the authors have recently designed a dual modality examination system using LV and 2D VKG for more detailed information regarding the vibrations of the vocal folds. The clinical availability of this hybrid system offers medical imaging departments a range of potential advantages in the evaluation of vocal fold vibration. The obvious benefit of simultaneous acquisition is the improved integration of information that allows not only optimal anatomic localization, but also physical movement patterns. Other advantages include the lessened inconvenience to patients due to no longer requiring repeated examinations and shortening the examination time, and increased profitability. The purpose of study was to identify the efficacy of real-time dual examination of two different modalities for the evaluation of vocal fold vibration in human subjects and vocal fold vibration simulator. METHODS: One vocally healthy subject and three patients with vocal fold nodules, a vocal cyst, and vocal fold paralysis took part in this study. The vibratory patterns of the vocal folds were visualized using simultaneous real-time examination of two different modalities. Additionally, qualitative and quantitative analyses of the dual LV and 2D VKG images were performed. RESULTS: Real-time dual examination using a two modality system provided high definition images of the vibratory movements of the vocal folds. By assessing the obtained images, we confirmed that the dual modality examination method was useful in the evaluation of pathologic vibratory patterns, even in non-periodic phonation. CONCLUSION: The present system might improve the understanding of the processes of vocal fold vibration and make a contribution to pathologic voice research, as well as clinical practice.

Development of a device for real-time light-guided vocal fold injection: A preliminary report.

OBJECTIVES/HYPOTHESIS: Vocal fold injection is a minimally invasive technique for various vocal fold pathologies. The shortcomings of the cricothyroid (CT) membrane approach are mainly related to invisibility of the injection needle. If localization of the needle tip can be improved during vocal fold injection with the CT approach, the current problems of the technique can be overcome. We have conceptualized real-time light-guided vocal fold injection that enables simultaneous injection under precise localization. In this study, we developed a device for real-time light-guided vocal fold injection and applied it in excised canine larynx. STUDY DESIGN: Animal model. METHODS: A single optic fiber was inserted in an unmodified 25-gauge needle. A designated connector for the device was attached to the needle, the optic fiber, and the syringe. A laser diode module was used as the light source. An ex vivo canine larynx model was used to validate the device. RESULTS: The location of the needle tip was accurately indicated, and the depth from the mucosa could be estimated according to the brightness and size of the red light. The needle was inserted and could be localized in the canine vocal fold by the light of the device. Precise injection at the intended location was easily performed with no manipulation of the device or the needle. CONCLUSIONS: Real-time light-guided vocal fold injection might be a feasible and promising technique for treatment of vocal fold pathology. It is expected that this technique can improve the precision of vocal fold injection and expand its indication in laryngology. LEVEL OF EVIDENCE: NA.

Imaging and Analysis of Human Vocal Fold Vibration Using Two-Dimensional (2D) Scanning Videokymography.

OBJECTIVE: Laryngeal videokymography and high-speed digital kymography are the currently available techniques for studying aperiodic vibration of the vocal folds. However, videokymography has a fundamental limitation that only linear portions of the vocal fold mucosa can be visualized, whereas high-speed digital kymography has the disadvantages of lack of immediate feedback during examination and considerable waiting time before kymographic visualization. We developed a new system, two-dimensional (2D) scanning videokymography, that provides a possible alternative for evaluation of the vibratory pattern of the vocal folds. Herein, we report the application of 2D scanning videokymography for visualization of vocal fold vibration in humans and an analysis of its parameters. MATERIALS AND METHODS: Two young healthy volunteers (one man and one woman) took part in this study. The vibratory patterns of their vocal folds were evaluated using 2D scanning videokymography and laryngeal stroboscopy. RESULTS: Two-dimensional scanning videokymography provided a high-definition image of the vibratory movements of the vocal folds. In analysis of the images acquired by the device, various parameters including fundamental frequency; ratio of the vibratory phases; phase, amplitude, and glottal area symmetry; and cycle-to-cycle variability were extracted. CONCLUSIONS: Our results indicate that 2D scanning videokymography is a useful and promising tool for visualization of the vibratory movement of the vocal folds. This new technique might improve our understanding of the mechanism of vocal fold vibration and contribute to voice research as well as clinical practice.

Changes and recovery of voice quality after sinonasal surgery.

Changes in the configuration of sinonasal cavity after surgery have been assumed to cause changes in the voice quality. The purpose of this study was to know when the hypernasality will be recovered after sinonsal surgery in patients with nasal septal deviation or chronic rhinosinusitis by checking long-term and serially obtained nasalance scores using nasometer. Sixty-five patients underwent sinonasal surgery were included. We classified the subjects into three groups according to the different surgical interventions employed: septoplasty group, endoscopic sinus surgery (ESS) group, and ESS with septoplasty group. The nasalance scores were obtained using a nasometer preoperatively, 1, 2, 3, 4, 5, and 6 months after surgery. The mean nasalance scores for vowels, nasal consonant, plosive consonant-vowel combinations, nasal consonant-vowel combinations, a hypernasality sentence, and hyponasality sentence increased significantly after sinonasal surgery. Hypernasality was most prominent in all groups for all acoustic parameters 1 month after surgery. Thereafter nasality decreased and returned to its preoperative level in all groups at 5 months in the [m], [ma], [mi], and hypernasality sentence, but at 6 months in the [a], [i], [u], [p(h)a], [p(h)i], and hyponasality sentence. Sinonasal surgery can change the acoustic characteristics of the vocal tract and produce a significant increase in nasality. After nasality showed the highest scores at 1-month post-surgery, it returned to its preoperative level at 5 or 6 months after surgery depending on the subtype of speech stimuli.