Brain adaptation following various unilateral vocal fold paralysis treatments: A magnetic resonance imaging based longitudinal case series.

Aim: Examination of central compensatory mechanisms following peripheral vocal nerve injury and recovery is essential to build knowledge about plasticity of the neural network underlying phonation. The objective of this prospective multiple-cases longitudinal study is to describe brain activity in response to unilateral vocal fold paralysis (UVFP) management and to follow central nervous system adaptation over time in three patients with different nervous and vocal recovery profiles. Materials and methods: Participants were enrolled within 3 months of the onset of UVFP. Within 1 year of the injury, the first patient did not recover voice or vocal fold mobility despite voice therapy, the second patient recovered voice and mobility in absence of treatment and the third patient recovered voice and vocal fold mobility following an injection augmentation with hyaluronic acid in the paralyzed vocal fold. These different evolutions allowed comparison of individual outcomes according to nervous and vocal recovery. All three patients underwent functional magnetic resonance imaging (fMRI task and resting-state) scans at three (patient 1) or four (patients 2 and 3) time points. The fMRI task included three conditions: a condition of phonation and audition of the sustained [a:] vowel for 3 s, an audition condition of this vowel and a resting condition. Acoustic and aerodynamic measures as well as laryngostroboscopic images and laryngeal electromyographic data were collected. Results and conclusion: This study highlighted for the first time two key findings. First, hyperactivation during the fMRI phonation task was observed at the first time point following the onset of UVFP and this hyperactivation was related to an increase in resting-state connectivity between previoulsy described phonatory regions of interest. Second, for the patient who received an augmentation injection in the paralyzed vocal fold, we subsequently observed a bilateral activation of the voice-related nuclei in the brainstem. This new observation, along with the fact that for this patient the resting-state connectivity between the voice motor/sensory brainstem nuclei and other brain regions of interest correlated with an aerodynamic measure of voice, support the idea that there is a need to investigate whether the neural recovery process can be enhanced by promoting the restoration of proprioceptive feedback.

A Systematic Review on Surgical Treatments for Sulcus Vocalis and Vocal Fold Scar.

OBJECTIVES/HYPOTHESIS: Vocal fold sulcus and scars are benign vocal fold lesions that present as a challenge to the laryngologist. A number of different surgical techniques have been proposed, aiming at restoring the lamina propria (LP), closing the glottal gap, or both. This study aimed to provide a systematic review of surgical treatment for sulcus and scar and to propose a new classification for these techniques. STUDY DESIGN: A literature search using MEDLINE and Google Scholar through August 2020. METHODS: Data on study design were retrieved and outcomes were classified as acoustic, aerodynamic, self-reported, perceptual, and stroboscopic. Methodological quality was assessed using the MINORs criteria. Each technique was classified as direct, indirect, or combined. RESULTS: Our search included 31 studies with a total of 617 patients. Direct techniques included dissection, graft interposition, or LP regeneration/scar degradation while indirect techniques aimed for glottal gap closure. Only one article performed a comparison between different types of techniques and only eight studied the five types of outcomes. No superiority of any technique was noted in our analysis. Self-reported outcomes were the most frequently improved. CONCLUSIONS: There seems to not exist a one-fits-all treatment for this clinical picture and no clear decision-making pattern. A recent trend toward sequential approaches, starting with less invasive procedures, can be observed. Laryngoscope, 132:822-830, 2022.

Does the wearing of masks change voice and speech parameters?

PURPOSE: The authors aim to review available reports on the potential effects of masks on voice and speech parameters. METHODS: A literature search was conducted using MEDLINE and Google Scholar databases through July 2021. Several targeted populations, mask scenarios and methodologies were approached. The assessed voice parameters were divided into self-reported, acoustic and aerodynamic. RESULTS: It was observed that the wearing of a face mask has been shown to induce several changes in voice parameters: (1) self-reported-significantly increased vocal effort and fatigue, increased vocal tract discomfort and increased values of voice handicap index (VHI) were observed; (2) acoustics-increased voice intensity, altered formants frequency (F2 and F3) with no changes in fundamental frequency, increased harmonics-to-noise ratio (HNR) and increased mean spectral values in high-frequency levels (1000-8000 Hz), especially with KN95 mask; (3) aerodynamics-maximum phonatory time was assessed in only two reports, and showed no alterations. CONCLUSION: Despite the different populations, mask-type scenarios and methodologies described by each study, the results of this review outline the significant changes in voice characteristics with the use of face masks. Wearing a mask shows to increase the perception of vocal effort and an alteration of the vocal tract length and speech articulatory movements, leading to spectral sound changes, impaired communication and perception. Studies analyzing the effect of masks on voice aerodynamics are lacking. Further research is required to study the long-term effects of face masks on the potential development of voice pathology.

Laryngeal Reinnervation: The History and Where We Stand Now.

Injury to the recurrent laryngeal nerve (RLN) can result in impairment of all three laryngeal functions. The RLN is capable of regeneration, but laryngeal functions in cases of severe injury remain impaired. This permanent impairment is caused by either incomplete regeneration and/or occurrence of laryngeal synkinesis. Laryngeal reinnervation can be approached either nonselectively, focusing on nerve reconstruction, or selectively, focusing on separate target muscle reinnervation. Nonselective reinnervation comprises anastomosis to the mainstem of the RLN leading to reinnervation of both abductor and adductor muscle groups (nerve-based reconstruction). In selective reinnervation, abductor and/or adductor muscles are separately reinnervated (function-based reconstruction). A review of laryngeal reinnervation techniques, results in animal models, and the results achieved in patients are given. The clinical implications of reinnervation in unilateral as opposed to bilateral vocal fold paralysis are considered. For unilateral vocal fold paralysis and nonselective reinnervation, good voice results can be achieved. It has the advantage that no foreign materials need to be implanted and may also be used in a growing larynx in the case of children or adolescents. For bilateral vocal fold paralysis, good functional results, recovery of airway as well as voice, can be achieved with selective (or function-based) reinnervation.

Accuracy of Thyroid Cartilage Fenestration During Montgomery Medialization Thyroplasty.

INTRODUCTION: Accuracy of thyroid cartilage fenestration during Montgomery thyroplasty (MTIS) is considered a key success factor. The primary aim of the study was to retrospectively evaluate the accuracy of fenestration. Furthermore, recent publications indicate a possible discrepancy in MTIS voice outcomes related to gender. The secondary aim of the study was to investigate whether the fenestration accuracy could explain this discrepancy. MATERIAL AND METHOD: Study was performed by virtually drawing the fenestration on a 3D CT scan as proposed by the MTIS's instructions for use (the "expected window" (EW)), and comparing it to the actually realized fenestration (the "realized window "(RW)). Four position variables, (a) surface overlap (%), (b) the distances between RW and EW centers (mm), (c) the angle between RW and EW (°), and (d) the orientation of RW's center, were studied and compared to MPT (seconds) and VHI-30 scores outcomes. A descriptive statistical analysis and comparison between males and females were performed using a Mann-Whitney U test. Linear regression and multivariate analysis were also performed. RESULTS: The median overlapping surface was 58.8 % [34.6; 75.4]. The median radius was 3.2 mm [1.7; 4.1]. The median angle was 16° [6.8; 21.2]. Results show no significant differences of overlapping surface percentage, distance, or angle by gender. Data show no correlation between voice outcome and percentage overlap, distance, or angle. However, data show better outcomes when fenestration was located in the infero-anterior orientation. All patients of this orientation were males. CONCLUSIONS: Data provided by this study advocate a maximal infero-anterior positioning of the window during MTIS. This position is more difficult to obtain in female patients.

The larynx ruler to measure height and profile of vocal folds: a proof of concept.

INTRODUCTION: Glottic leakage during phonation is a direct consequence of unilateral vocal fold (VF) paralysis. This air leakage can be in the horizontal plane and in the vertical plane. Presently, there is no easily applicable medical device allowing noninvasive, office-based measurement of the relative vertical position of the VFs. The larynx ruler (LR) is a laser-based measuring device that could meet the previously stated need, using a flexible endoscope. This study represents a proof of concept regarding the use of the LR in assessing VF relative positions in the vertical plane. MATERIALS AND METHODS: One fresh male human cadaver larynx, free of neurologic and anatomic disease, was explored with the LR system through the operative channel of a flexible gastroenterology video-endoscope. The tip of the video-endoscope was located in the laryngeal vestibule. The right crico-arytenoid joint was posteriorly disarticulated. Tilting of the VF was obtained by pulling or pushing the arytenoid cartilage with a mosquito forceps fixed to the stump of the previously sectioned superior tip of the posterior crico-arytenoid muscle allowing anterior and posterior tilting of the arytenoid cartilage in order to induce an elevation or a depression of the VF process. Ten "push" and ten "pull" sessions were performed. The distance from the tip of the video-endoscope to each illuminated pixel of the laser beam was recorded. The level difference between the left and right VFs was measured for each recording. RESULTS: Data provided by the LR were consistently in accordance with the movements applied on the VFs. The accuracy of 0.2 mm of the LR is compatible with the envisioned applications for the human larynx. CONCLUSION: The LR system represents a feasible technique to evaluate respective vertical position of VFs in the human larynx. Technical limitations were identified that will require improvements before experimental use on human beings.

Shape of Thyroid Cartilage Influences Outcome of Montgomery Medialization Thyroplasty: A Gender Issue.

OBJECTIVE: This study aimed to determine whether the shape of the thyroid cartilage and gender influence voice outcomes after a Montgomery thyroplasty implant system (MTIS). METHODS: A retrospective cohort study was performed on 20 consecutive patients who underwent MTIS. Voice outcome variables were the relative decrease in Voice Handicap Index (%) and the absolute increase in maximum phonation time (MPT) (in seconds). Material variables were the angle between the thyroid cartilage laminae (α-angle), the size of the prosthesis, and a combination of both (the α-ratio). Continuous variables were analyzed using medians and were compared between groups using the Mann-Whitney U test. Factors associated with the outcome variables were assessed by multivariable linear regression. A Pearson coefficient was calculated between material variables. RESULTS: The absolute increase in MPT between the pre- and postoperative period was significantly different between men and women, with a median absolute increase of 11.0 seconds for men and of 1.3 seconds for women (P < 0.001). A strong inverse correlation between the α-ratio and the absolute increase in MPT is observed in all patients, with a Pearson correlation coefficient R = -0.769 (P < 0.001). No factors were significantly associated with the relative Voice Handicap Index decrease in univariable or multivariable analyses. A better Pearson coefficient between the α-angle and the prosthesis size was found for females (0.8 vs 0.71). CONCLUSION: The MTIS is a good thyroplasty modality for male patients, but inadequate design of MTIS female implants leads to poor MPT outcomes. This represents a gender issue that needs to be further studied and eventually tackled.