Toshihiko Iwahashi

Immediate Effects of Humming on Computed Electroglottographic Parameters in Patients With Muscle Tension Dysphonia

OBJECTIVES To investigate the immediate effects of humming and subsequent um-hum phonation on the computed parameters of electroglottographic (EGG) signals in muscle tension dysphonia (MTD) patients and nondysphonic speakers. METHODS We included 21 MTD participants exhibiting both vocal roughness and supraglottic compression, who were able to produce successful humming and um-hum phonation. Twenty nondysphonic participants were selected as controls. Each participant was instructed to perform three phonatory tasks: natural phonation, humming phonation without pitch changes, and subsequent um-hum phonation, that is, humming with a pitch glide up as if agreeing with someone. Acoustic and EGG signals were recorded while the participants performed these tasks. Computed parameters reflecting the irregularities in vocal fold vibrations and the degree of glottal contact were calculated and compared between the tasks. RESULTS The MTD group showed decreases in both perceptual vocal roughness and acoustic perturbation parameters while performing the tasks. The perturbation parameters of EGG signals and the standard deviation of the contact quotient (CQ) also exhibited significant decreases associated with either of humming or um-hum phonation in both groups. In addition, the CQ exhibited significant increases following humming alone in the MTD group and the combination of humming and um-hum phonation in both groups. CONCLUSIONS These results suggest that the combination of humming without pitch changes and subsequent um-hum phonation have the immediate effect in adjusting the regularity of vocal fold vibration and augmenting the degree of glottal contact in MTD patients as well as nondysphonic speakers, whereas humming alone increases the degree of glottal contact in MTD patients.

Validation of the Acoustic Voice Quality Index in the Japanese Language

OBJECTIVES The Acoustic Voice Quality Index (AVQI) is a multivariate construct for quantification of overall voice quality based on the analysis of continuous speech and sustained vowel. The stability and validity of the AVQI is well established in several language families. However, the Japanese language has distinct characteristics with respect to several parameters of articulatory and phonatory physiology. The aim of the study was to confirm the criterion-related concurrent validity of AVQI, as well as its responsiveness to change and diagnostic accuracy for voice assessment in the Japanese-speaking population. STUDY DESIGN This is a retrospective study. METHODS A total of 336 voice recordings, which included 69 pairs of voice recordings (before and after therapeutic interventions), were eligible for the study. The auditory-perceptual judgment of overall voice quality was evaluated by five experienced raters. The concurrent validity, responsiveness to change, and diagnostic accuracy of the AVQI were estimated. RESULTS The concurrent validity and responsiveness to change based on the overall voice quality was indicated by high correlation coefficients 0.828 and 0.767, respectively. Receiver operating characteristic analysis revealed an excellent diagnostic accuracy for discrimination between dysphonic and normophonic voices (area under the curve: 0.905). The best threshold level for the AVQI of 3.15 corresponded with a sensitivity of 72.5% and specificity of 95.2%, with the positive and negative likelihood ratios of 15.1 and 0.29, respectively. CONCLUSIONS We demonstrated the validity of the AVQI as a tool for assessment of overall voice quality and that of voice therapy outcomes in the Japanese-speaking population.

A Detailed Motion Analysis of the Angular Velocity Between the Vocal Folds During Throat Clearing Using High-speed Digital Imaging

OBJECTIVES To assess the angular velocity between the vocal folds just before the compression phase of throat clearing (TC) using high-speed digital imaging (HSDI) of the larynx. METHODS Twenty normal healthy adults (13 males and seven females) were enrolled in the study. Each participant underwent transnasal laryngo-fiberscopy, and was asked to perform weak/strong TC followed by a comfortable, sustained vowel phonation while recording an HSDI movie (4000 frames/s) of the larynx. Using a motion analysis, the changes in the vocal fold angle and angular velocity during vocal fold adduction were assessed. Subsequently, we calculated the average angular velocities in the ranges of 100-80%, 80-20%, and 20-0% from all of the angular changes. RESULTS The motion analysis demonstrated that the changes in the angular velocity resulted in polynomial-like and sigmoid curves during TC and vowel phonation, respectively. The angular velocities during weak TC were significantly higher in the 20-0%, 80-20%, and 100-80% regions (in order); the 80-20% angular velocity in vocal fold adduction during phonation was highest. The 20-0% angular velocity during strong TC was more than twofold higher than 20-0% angular velocity during phonation. CONCLUSIONS The present results confirmed that the closing motions of the vocal folds accelerate throughout the precompression closing phase of a TC episode, and decelerate just before the impact between the vocal folds at the onset of phonation, suggesting that the vocal fold velocity generated by TC is sufficient to damage the laryngeal tissues.

The Effects of Humming on the Prephonatory Vocal Fold Motions Under High-Speed Digital Imaging in Nondysphonic Speakers

OBJECTIVES This study aimed to investigate whether humming affects the adductive motion of the vocal folds and transient glottal closure in the prephonatory adjustment phase of vocal onset using high-speed digital imaging (HSDI) and a motion analysis software program. METHODS Twenty normal healthy adults without any vocal abnormalities were enrolled. While a transnasal flexible fiberscope connected to a high-speed camera was inserted, each participant was asked to perform three phonatory tasks-natural /e:/ phonation, loud /e:/ phonation, and humming /m:/ phonation-and laryngeal HSDI movies (4000 frame/s) were recorded. On each HSDI movie, the duration of the prephonatory glottal closure was measured. In addition, using motion analysis, the changes in the angle between the bilateral vocal folds during vocal fold adduction and the average angular velocity in the ranges of 100%-80%, 80%-20%, and 20%-0% from all of the angular changes were analyzed. RESULTS The angular changes showed sigmoid and polynomial-like curves during the natural/humming and loud phonation, respectively, and the 80%-20% and 20%-0% average velocities were the highest during the natural/humming and loud phonation, respectively. The humming phonation decreased all of the average regional velocities, eliminated the transient prephonatory glottal closures observed during the natural and loud phonation, and induced a greater value for the minimal angle than the natural phonation. CONCLUSIONS The present study demonstrates that humming encourages easy vocal initiation by decelerating the vocal fold adductive motion throughout the prephonatory adjustment phase and alleviating transient prephonatory laryngeal closure, leading to gradual and smooth vocal fold positioning.

The results of Kaplan-Meier and multivariate analyses of etiological factors related to the outcome of combined pharmacological therapy against laryngeal granuloma

Abstract Conclusions: The present results indicate that the diagnosis of gastroesophageal reflux disease (GERD) is an independent etiological factor predicting retardation of the resolution of laryngeal granuloma. Objectives: To assess the effects of combined usage of an inhaled corticosteroid plus tranilast and/or a proton pump inhibitor on the size of granulomatous lesions, and to reveal etiological factors related to the outcome using the Kaplan-Meier method and a subsequent multivariate analysis. Methods: Sixty-two patients with laryngeal granuloma were enrolled. An inhaled corticosteroid plus tranilast (300 mg/day) and rabeprazole (20 mg/day) were administered to all of the patients, and only to those diagnosed to have GERD, respectively. The size of granulomatous lesion was measured for each patient at the initial visit and every 4 weeks. At 48 weeks, the Kaplan-Meier plots for lesion disappearance rate were compared between groups with and without each of the etiological factors, followed by Cox proportional-hazards regression. Results: The 48-week lesion disappearance rates for the whole population were 82.3%. Although the Kaplan-Meier analysis exhibited significant differences between patients separated by GERD diagnosis, phonotrauma, and habitual smoking, only GERD were identified as a real independent etiological factor affecting the resolution of the lesion by a multivariate analysis using Cox’s proportional-hazards regression.

The Acoustic Voice Quality Index Version 03.01 for the Japanese-speaking Population

OBJECTIVES We aimed to determine the most appropriate syllable number for analyzing the Acoustic Voice Quality Index for the Japanese-speaking population (AVQIv3-JP) and to validate AVQIv3-JP using the determined syllable number. METHODS First, we counted how many syllables should be included in each continuous speech (CS) sample to achieve time-balanced analysis between CS and sustained vowel samples using our previous dataset including 336 CS samples with 58 syllables. From the descriptive statistics of the counted syllable numbers, the most appropriate syllable number was identified. Subsequently, we performed validation procedures of AVQIv3-JP using our latest dataset including 455 recordings. RESULTS Thirty Japanese syllables were judged to be the most appropriate syllable number. The concurrent validity of the AVQIv3-JP using 30 syllables was confirmed by Spearmans rho of 0.873. Subsequently, the receiver operating characteristic analysis demonstrated the excellent discriminative capability of AVQIv3-JP, showing the area under the curve of 0.915. The AVQIv3s original threshold of 2.43 in the Dutch language corresponded to sensitivity and specificity of 64.6% and 97.3%, respectively. In the present study, a threshold of 1.41 achieved the best accuracy with balanced sensitivity and specificity of 84.4% and 85.6%, respectively. Furthermore, the 95th percentile of the control participants exhibited a threshold of 2.06, showing sensitivity and specificity of 72.1% and 93.8%, respectively, as well as reasonable positive and negative likelihood ratios of 11.7 and 0.298, respectively. CONCLUSION The AVQIv3 using 30 Japanese syllables is a reliable measurement tool for estimating the severity of voice quality and detecting abnormal voices.

Computed tomographic assessment of the causal factors of unsuccessful medialization thyroplasty

Abstract Conclusion: The present results demonstrate that a small implant size, undercorrection of the vocal fold, antero-posterior implant malposition, and the use of expanded polytetrafluoroethylene (ePTFE) are the primary factors that cause a poor outcome of medialization thyroplasty (MT). Objectives: To assess the postoperative laryngeal condition using computed tomography (CT) in patients with unilateral vocal fold paralysis who underwent MT alone, and to identify the primary causal factors in terms of the surgical procedures that affect the outcomes of MT. Methods: Twenty-two patients who underwent MT alone were divided into two groups based on either the maximal phonation time or the perceived vocal breathiness. Two laryngologists assessed the postoperative laryngeal CT images during sustained vowel phonation and judged whether there were abnormalities of the arytenoid cartilage position, window position, implant size, and implant position, as well as the degree of correction of the vocal fold. As implant material, a silicone block, ePTFE, and hydroxyapatite had been inserted in 2, 9, and 11 patients, respectively. Comparisons of the prevalence of abnormalities in the abovementioned factors between the different outcomes and between the types of material used for the implant were performed. Results: Twelve patients with a poor outcome and 10 with a good outcome showed 36 and 18 abnormal findings identified by either of the two laryngologists, respectively. In the poor outcome group, a smaller implant size and undercorrection of the vocal fold showed both high kappa values and a significantly higher prevalence than those in the good outcome group (p < 0.001 and p < 0.05), respectively. The comparison between material types demonstrated that the sheet-like material (ePTFE) group exhibited a significantly higher prevalence of undercorrection than the block-like material group (p < 0.05).

Measurement of the Maximum Frequency of Electroglottographic Fluctuations in the Expiration Phase of Volitional Cough as a Functional Test for Cough Efficiency

The hypotheses of the present study were that the maximum frequency of fluctuation of electroglottographic (EGG) signals in the expiration phase of volitional cough (VC) reflects the cough efficiency and that this EGG parameter is affected by impaired laryngeal closure, expiratory effort strength, and gender. For 20 normal healthy adults and 20 patients diagnosed with unilateral vocal fold paralysis (UVFP), each participant was fitted with EGG electrodes on the neck, had a transnasal laryngo-fiberscope inserted, and was asked to perform weak/strong VC tasks while EGG signals and a high-speed digital image of the larynx were recorded. The maximum frequency was calculated in the EGG fluctuation region coinciding with vigorous vocal fold vibration in the laryngeal HSDIs. In addition, each participant underwent spirometry for measurement of three aerodynamic parameters, including peak expiratory air flow (PEAF), during weak/strong VC tasks. Significant differences were found for both maximum EGG frequency and PEAF between the healthy and UVFP groups and between the weak and strong VC tasks. Among the three cough aerodynamic parameters, PEAF showed the highest positive correlation with the maximum EGG frequency. The correlation coefficients between the maximum EGG frequency and PEAF recorded simultaneously were 0.574 for the whole group, and 0.782/0.717/0.823/0.688 for the male/female/male-healthy/male-UVFP subgroups, respectively. Consequently, the maximum EGG frequency measured in the expiration phase of VC was shown to reflect the velocity of expiratory airflow to some extent and was suggested to be affected by vocal fold physical properties, glottal closure condition, and the expiratory function.