[Analysis of vocal fold vibration characteristics of spasmodic dysphonia by laryngeal high speed photography combined with glottis area wave].

Objective: To analyze the characteristics of vocal fold vibration of normal people and patients with spasmodic dysphonia (SD) using laryngeal high speed videoendoscopy combined with glottal area wave analysis. Methods: This prospective study examined twenty healthy subjects (10 males and 10 females), 12 patients with adductor spasmodic dysphonia(AdSD) (2 males,10 females)as AdSD group and 2 patients with abductor spasmodic dysphonia(AbSD) (2 males) as AbSD group. Twelve of healthy subjects (2 males,10 females) were selected as control group according to AdSD group gender match. All the subjects were recruited from the Department of Voice, Zhongshan Hospital, Xiamen University from October 2019 to December 2020. All subjects underwent laryngeal high speed videoendoscopy and 10 vibration periods were selected from each recording and were used to quantitatively analyze the change of glottal area and vocal fold vibration parameters (Speed Quotient (SQ), Open Quotient (OQ) and Close Quotient (CQ)). Results: 1. There were statistically significant differences in SQ, CQ and OQ between males and females in the healthy subjects (t=12.28, 5.59, 5.59, P<0.05). The change of the glottal area during each vibration period in healthy subjects was relatively stable(0.19-0.42). 2. The change of the glottal area during each vibration period in AdSD subjects had larger fluctuations, with the glottal area change index fluctuating in the range of 0.31 to 0.62. The SQ value of the AdSD group was significantly lower than that of control group (t=4.246, P<0.05). There were no significant differences in OQ and CQ between AdSD group and normal group (t=1.064, 1.332, P>0.05); The SQ value of the AbSD group tended to increase compared to normal group. Conclusions: Laryngeal high speed videoendoscopy combined with glottal area wave analysis has a certain reference value in the studying the vibration characteristics of SD patients. SQ has good specificity.

[Application of dynamic CT scan in the three-dimensional dynamic morphology changes of laryngeal soft tissue in unilateral vocal fold paralysis patients].

Objective: To explore the dynamic changes of three-dimensional morphology of laryngeal soft tissue and its clinical value in the unilateral vocal fold paralysis (UVFP) patients through dynamic CT scanning during the process from inspiration to phonation. Methods: From October 2017 to July 2019, a retrospective study was performed in 18 patients with UVFP (10 males and 8 females with the range of age from 29 to 75 years old) and 10 normal subjects (5 males and 5 females with the range of age from 25 to 58 years old) in Department of Voice-Otolaryngology Head and Neck Surgery, Section Two, Zhongshan Hospital Xiamen University. The laryngeal dynamic computed tomography (CT) of cine mode was performed. Ten dynamic sequence images of vocal folds movements were obtained during the process from inspiration to phonation. Based on the dynamic changes of glottic area and the displacement of cricoid cartilage. The above dynamic sequence images were divided into inspiratory phase and phonation phase as well as open phase and closed phase. The soft tissue parameters were measured respectively, including vocal folds length, width, thickness and subglottal convergence angle. Independent-sample t test was used to analyze between UVFP group and control group. Results: During the process from inspiration to phonation, the morphology of vocal folds in control group was relatively stable at inspiratory phase and closed phase in phonation. When open phase and closed phase of phonation were switching, the morphology of vocal folds changed obviously. The length of vocal folds became longer (1.19±0.10) mm, the width became wider (2.19±0.17) mm, the thickness became thinner (2.66±0.56) mm, and the subglottal convergence angle decreased (31.45±4.78)°. Compared with the controll group, in the open phase, the thickness and width of the vocal fold on affected side in the UVFP group were thinner (t=10.25, P<0.001) and wider (t=5.25, P<0.001).While in the closed phase, the subglottal convergence angle was larger (t=4.41, P=0.001).The width of the healthy side vocal fold in the UVFP was wider (t=2.54, P=0.026) than that in the control group. The differences in other parameters were not statistically significant. Conclusions: Dynamic laryngeal CT scanning provides a simple and non-invasive method for the objective and quantitative measurement of the dynamic changes of laryngeal morphology from inspiration to phonation. Compared with the control group, the characteristic dynamic changes among UVFP were observed during this particular process, which included changes of subglottal convergence angle and thickness of vocal muscle due to denervation. In addition, in UVFP group, the width of the vocal fold healthy side in the closed phase may be used to assess its compensatory function.

[Effect of cricothyroid and thyroarytenoid muscle botulinum toxin injection on patients with dyspnea caused by bilateral recurrent laryngeal nerve paresis].

Objective: To discuss the clinical effect of small dose of botulinum toxin injection in cricothyroid muscle and thyroarytenoid muscle on patients with incomplete bilateral recurrent laryngeal nerve paresis. Methods: Six patients were selected with Ⅰor Ⅱ or Ⅲ degree of dyspnea diagnosed as bilateral recurrent laryngeal nerve injury by laryngeal electromyography, and small dose of botulinum toxin injection was performed in cricothyroid muscle and thyroarytenoid muscle as a treatment. Degree of dyspnea was assessed one month before and after the treatment, and the stroboscopic laryngoscope results, acoustic parameters and CT image of the patients were collected in the 6 patients. The relevant parameters were also collected one month before and after treatment, including the degree of dyspnea, stroboscopic laryngoscope results, acoustic parameters and CT image of the patients. The angle between bilateral vocal cords in stroboscopy at full inspiratory was calculated, acoustic parameters (F0, jitter, shimmer) were analysed, and vocal length, width and the vocal region were measured. Then, the paired t test was performed for statistical analysis between before and after one month injection, the one way analysis of variance was performed among vocal parameters in CT image. Result: Botulinum toxin injection was successfully completed in the 6 patients, followed without any serious complications. The degree of dyspnea was alleviated to some extent after treatment in all 6 patients; the angle between bilateral vocal cords at the end of a deep inspiration was significantly increased (t=2.44, P<0.05) after the treatment. The changes of F0 and jitter between before and after treatment were not statistically significant (t=0.72, t=1.42, P>0.05). Shimmer was significantly decreased after treatment (t=2.61, P<0.05). Vocal fold length, width and vocal region increased with F0, there was a statistically significant difference between different F0 before injection, and there was no statistically significant difference between different F0 after injection. The follow-up time was respectively seven months, 1 year, 1 year, 18 months, 22 months and 2 years respectively. Conclusion: Small dose of botulinum toxin injection in bilateral cricothyroid muscles and thyroarytenoid muscles can relieve the dyspnea caused by bilateral vocal cords paresis to some extent, accompanied without serious complications, despite the sound quality was slightly worse.

[Effect of extent of glottal incompetence on phonation in excised canine larynx models].

Objective: To compare the acoustic signal, mucosal wave and aerodynamic parameter (phonation threshold pressure, PTP) under different sub-glottal pressure (SGP) on the excised canine models with different extent of glottal incompetence. Methods: Perturbation measures and nonlinear dynamic measures were applied to analyze the acoustic signal (jitter, shimmer), mucosal wave [frequency(F), amplitude(A), phase(P)] and PTP from our study including 11 excised canine larynges with different extent of glottal incompetence (0 mm, 1 mm, 2 mm, 3 mm, n=11, respectively) under 1-4 kPa sub-glottal pressure. Results: There were significant differences between different groups in jitter, shimmer, amplitude, frequency and PTP under various SGPs and extent of glottal incompetence (all P<0.05), inversely, there was no significant difference in P between groups (P>0.05). Jitter and shimmer changed obviously when the SGP increased to 3 kPa in the control group and GI 1 mm group. Jitter and shimmer changed obviously when the SGP increased to 2 kPa in the GI 2 mm and 3 mm groups. The F and A of mucosal wave increased with increasing SGP, decreased with increasing GI, and the P changed irregularly. There was statistically significant difference of PTP between different GI groups. Conclusions: The SGP and the extent of GI had obvious affection on the the acoustic signal, mucosal wave and aerodynamic parameters.

[A study on the X-ray measurement predictors of difficult laryngealexposure in patients undergoing microlaryngosurgery].

Objective:This paper seeks to identify useful and reliable indicators for predicting the occurrence of difficult laryngeal exposure(DLE) in microlaryngosurgery.Method:Sixty-two patients were given physical examinations,including 4 general parameters:age,sex,BMI,and MMI,and 14 physical measurement parameters(TA,UIA,LIA,IG,LIMD,MA,MCD,MH,MDI,HMD,TMD,SMD,TMA,THUIA).Univariate analysis,stepwise regression analysis and ROC curve analysis were employed to identify parameters with the potential to predict DLE.Result:We found sex(P<0.05) showed significant correlation with the laryngeal exposure score(P<0.05).We also found LIMD,MA,TMA and THUIA to be reliable DLE predictors.The cutoff values for predicting DLE were LIMD>4.53cm,MA>115.5°,TMA>99.2°,and THUIA>152.6°.Conclusion:X-ray measurement predictors of LIMD,MA,TMA,and THUIA before operation are important for the prediction of DLE.Sex is also the reliable DLE predictor.Males were prone to DLE.

[The role of acoustic analysis of fundamental frequency in differentiating arytenoid dislocation from vocal fold paralysis].

Objective:Analysis of the sustained vowels of acoustic parameters in arytenoid dislocation and vocal fold paralysis. To investigate their acoustic characteristics and evaluate the role of this acoustic analysis method in differentiating arytenoid dislocation from vocal fold paralysis. Method:Thirty-three cases with unilateral vocal cord movement disorders were collected.All cases were divided into arytenoid dislocation group and vocal fold paralysis group through the laryngeal electromyography. Each group was further devided into male group and female group. The voice signals of sustained vowel of /a/ were measured using the software MDVP and obtain the acoustic parameters(Jitter, Shimmer, SPI and Fo). The acoustic characteristics between the two groups were observed and compared. Results were analyzed using Rank sum test for group design.Result:There were significant differences in Fo between arytenoid dislocation group and vocal fold paralysis group in both male and female group（P <0.05）. And mean rank order of Fo in arytenoid dislocation group was greater than vocal fold paralysis group. There were no significant differences in jitter,shimmer and SPI between arytenoid dislocation group and vocal fold paralysis group（P >0.05）.Conclusion:Mean rank order of Fo in arytenoid dislocation group is greater than vocal fold paralysis group in both the male and the female group. Fo is of value in differentiating arytenoid dislocation from vocal fold paralysis. This provides a theoretical basis for the acoustic analysis method to identify these two diseases.