Laryngeal Videostroboscopy Research Articles

Computerized Analysis of Vocal Folds Vibration From Laryngeal Videostroboscopy

To develop an objective analysis of laryngeal videostroboscopy (VSS) movies in the space-time domain for quantitative determination of the true vocal folds (TVFs) vibratory pattern to allow for detection of local pathologies at early stages of development. Contours of the TVF and false vocal folds (FVFs) were tracked on each frame of a VSS movie. A registration algorithm was used with respect to the centerline of the FVF to eliminate movements not related to TVF vibration. The registered contours of the TVF were analyzed in time and frequency domains. The TVF vibration demonstrated a sinusoidal pattern with the same fundamental frequency at every section along the folds of healthy subjects, as well as detection of an abnormal area with a different fundamental frequency in TVF with local pathologies. Analysis of the TVF vibration time delay of healthy subject revealed a posterior-to-anterior longitudinal wave that was not detected by visual observation. An objective analysis of laryngeal VSS movies was developed for quantitative determination of the TVF vibration. This analysis was able to detect and quantify TVF characteristics in normal subjects as well as in patients with pathologies beyond the ability of examinee's naked eyes.

Transnasal injection laryngoplasty.

The objective of this study was to evaluate the role of transnasal fiber-optic injection laryngoplasty in the treatment of glottic insufficiency. Video recordings of 16 patients who underwent fiber-optic injection laryngoplasty for the treatment of glottic insufficiency were reviewed. Outcome measures included perceptual evaluation using the GRBAS (grading, roughness, breathiness, asthenia, straining) classification, laryngeal videostroboscopy, and frame-by-frame analysis to assess the extent, shape, and duration of glottic closure. Nine patients were ultimately included in this study. Their mean age was 66.2 years, with 7 men and 2 women. The most common symptoms were dysphonia and aspiration, and the most common diagnosis was vocal fold paralysis. Patients underwent transnasal fiber-optic injection laryngoplasty with hyaluronic acid as a filling material (0.2-0.8 mL). The procedure was well tolerated by all patients, with improvement in the phonatory symptoms and aspiration in 66.66% and 50% of patients, respectively. There were significant decreases in the mean scores of all perceptual parameters (P<.05 for all). All subjects had glottal gap preoperatively that was closed completely in 66.66% and reduced to <2 mm in 33.33%. The mean closed quotient significantly increased from 0.10 to 0.51 (P<.05). Transnasal fiber-optic injection laryngoplasty is a safe procedure well tolerated by patients with good results.

Prevalence and risk factors of voice disorders among attendants of the Speech Unit at King Abdulaziz Medical City, Riyadh, Saudi Arabia

Introduction: Voice disorders are defined as effortful or difficulties in phonation and deviant voice qualities that are often associated with discomfort and disability. The causes of voice disorders can be classified as congenital or acquired. Many authors have investigated the prevalence of voice disorders in the general population. Others have investigated the risk factors for voice disorders, such as high vocal demand, age, gender, smoking and gastro-oesophageal reflux. Objectives: To determine the prevalence of voice disorders among patients of the Speech Unit at King Abdulaziz Medical City (KAMC) and identify variables associated with increased risk for voice disorders. Materials and methods: A retrospective, cross-sectional study was conducted to estimate the prevalence of voice disorders among all patients who attended the Speech Unit at KAMC, Riyadh, Saudi Arabia, during the period from 2008 to 2013. Data were extracted from the QuadraMed (Reston, VA, USA) hospital information system and the database of the laryngeal videostroboscopy. Patient information was reviewed for key variables, such as age, gender, occupation, smoking history and history of known related diseases. Descriptive univariate analysis was carried out to identify variables associated with high risk of voice disorders. Results: The overall prevalence of voice disorders of all patients attending the Speech Unit was 12.1%. Of the sample studied, 52% were female and 48% were male. Only 16.2% of the patients with voice disorders were smokers. The analysis of occupation showed that 28.26% were housewives, 17.8% were students and 11.12% were teachers. Conclusions: The result of this study provides valuable information about the prevalence and risk factors and different aetiology of voice disorders. Acknowledgements: Dr Nasser Hassan for supervising this project.

Current role of stroboscopy in laryngeal imaging

To summarize recent technological advancements and insight into the role of stroboscopy in laryngeal imaging. Although stroboscopic technology has not undergone major technological improvements, recent clarifications have been made to the application of stroboscopic principles to video-based laryngeal imaging. Also recent advances in coupling stroboscopy with high-definition video cameras provide higher spatial resolution of vocal fold vibratory function during phonation. Studies indicate that the interrater reliability of visual stroboscopic assessment varies depending on the laryngeal feature being rated and that only a subset of features may be needed to be representative of an entire assessment. High-speed videoendoscopy (HSV) judgments have been shown to be more sensitive than stroboscopy for evaluating vocal fold phase asymmetry, pointing to the future potential of complementing stroboscopy with alternative imaging modalities in hybrid systems. Laryngeal videostroboscopy alone continues to play a central role in clinical voice assessment. Even though HSV may provide more detailed information about phonatory function, its eventual clinical adoption will depend on how remaining practical, technical, and methodological challenges will be met. Laryngeal videostroboscopy continues to be the modality of choice for imaging vocal fold vibration, but technological advancements in HSV and associated research findings are driving increased interest in the clinical adoption of HSV to complement videostroboscopic assessment.

Frontolateral Laryngectomy with Imbrication Laryngoplasty for Stage I Glottic Carcinoma

Frontolateral Laryngectomy with Imbrication Laryngoplasty for Stage I Glottic Carcinoma

Voice Quality after Recurrent Laryngeal Nerve Resection and Immediate Reconstruction

To evaluate clinician perception of voice quality, patient self-reported psychosocial impact of dysphonia, and glottic closure in patients who have undergone resection of the recurrent laryngeal nerve (RLN) and immediate operative reconstruction during thyroid surgery. Prospective observational study. Single tertiary care hospital. Nine patients underwent immediate operative reconstruction of the RLN by the senior author from 2002 to present. Outcome measures included (1) perceptual voice ratings assessed using the GRBAS (Grade, Roughness, Breathiness, Asthenia, Strain) scale, (2) psychosocial impact of dysphonia assessed using the Voice Handicap Index (VHI), and (3) assessment of glottic closure from laryngeal videostroboscopy. The RLN was reconstructed with primary anastomosis (4), free nerve graft (3), or vagus-RLN anastomosis (2). Seven patients had voice samples and videostroboscopy examinations obtained at a minimum of 9 months from surgery. Six were judged to have slight disturbance of voice based on overall Grade scoring (G = 1). Five rated their voice as normal or mild on the VHI instrument (score range 8-29). Laryngeal analysis revealed the immobile vocal fold in the median, physiologic phonating position with preserved bulk, recovered tension, and glottic closure during phonation. Three patients less than 9 months from surgery had an expected severe self-reported rating of dysphonia. Primary anastomosis, free nerve grafting, and vagus-RLN anastomosis are viable options for RLN reconstruction. Patients who undergo resection and immediate reconstruction of the RLN are able to regain self-perceived functional voices.

Vocal Folds Analysis Using Global Energy Tracking

Detection and quantification of oscillatory irregularities in laryngeal videostroboscopy can be particularly difficult for the human expert. Accordingly, there is a wide interest in automated methods for recovering the folds' temporal trajectory. Unfortunately, current methods typically provide only crude glottal measurements. An automated procedure for consistently tracking the entire vocal folds' boundary in laryngeal stroboscopy videos, even when the glottal opening is closed. A preprocessing frame-by-frame crude midpoint identification is followed by an active contour evolution to detect the global boundary in each frame independently. A global energy active contour is then jointly defined over the entire video sequence, and the full glottal boundary is detected throughout the video via standard energy minimization. The vocal folds' boundary is accurately tracked in normal and abnormal stroboscopy videos collected in a clinical setting, and that exhibit a varied range of visual characteristics (eg, lighting conditions). A proof-of-concept evaluation based on the analysis of the waveform of the location of points along the boundary separates between a normal and two markedly different abnormal subjects, and automatically provides a hypothesized localization of the abnormality. The first method for automatically tracing the temporal trajectory of all points along the vocal folds' boundary in all frames of a stroboscopy video is presented. The approach opens the door for novel analysis of all regions of the contour, which in turn may lead to automated localization of pathologies.

Short term effect of hubble-bubble smoking on voice

To investigate the short term effect of hubble-bubble smoking on voice. Prospective study. Eighteen non-dysphonic subjects (seven men and 11 women) with a history of hubble-bubble smoking and no history of cigarette smoking underwent acoustic analysis and laryngeal video-stroboscopic examination before and 30 minutes after hubble-bubble smoking. On laryngeal video-stroboscopy, none of the subjects had vocal fold erythema either before or after smoking. Five patients had mild vocal fold oedema both before and after smoking. After smoking, there was a slight increase in the number of subjects with thick mucus between the vocal folds (six, vs four before smoking) and with vocal fold vessel dilation (two, vs one before smoking). Acoustic analysis indicated a drop in habitual pitch, fundamental frequency and voice turbulence index after smoking, and an increase in noise-to-harmonics ratio. Even 30 minutes of hubble-bubble smoking can cause a drop in vocal pitch and an increase in laryngeal secretions and vocal fold vasodilation.

Vocal Changes in Patients With Polycystic Ovary Syndrome

The purpose of this study is to look at the prevalence of vocal symptoms and acoustic changes in patients with polycystic ovary syndrome (PCOS). A total of 17 patients with PCOS diagnosed on the basis of three criteria: the presence of irregular menstrual cycles, hirsutism, and polycystic ovaries were included in the study. Twenty-one normal females' frequencies matched on age with the cases were used as controls. The following vocal symptoms were investigated: throat clearing, deepening of the voice, loss of voice, lump in the throat, and difficulty being heard. Acoustic analysis and laryngeal videostroboscopy were performed. The age range was between 19 and 38 years with a mean age of 26 years. The most common prevailing symptom was throat clearing present in 76.5% versus 4.8% in the controls, followed by loss of voice (47.6%), lump in the throat (41.2%), and deepening of voice (35.3%). The differences in the prevalence of throat clearing, deepening of voice, lump in the throat, and difficulty being heard were statistically significant compared with controls (P value<0.05). There was no statistically significant difference in the acoustic parameters except for an increase in the relative average perturbation (P value=0.035) and a decrease in maximum phonation time (P value=0.001) in patients with PCOS. In the PCOS group, three patients had evidence of mild vocal fold edema and one patient had vocal fold nodules. In the control group, one subject had vocal fold edema and one subject had vocal fold nodules. Patients with PCOS seem to have more vocal symptoms compared with controls. Physicians should be aware of vocal changes in hirsute subjects with PCOS.

Effect of fasting on voice in males

Purpose of the study The aim of the study was to study how fasting between 12 and 14 hours affects voice production. Study design This is a prospective study of male subjects. Material and method A total of 26 healthy male subjects were recruited for the study. The age varied between 22 and 50 years with a mean of 28 years. Exclusion criteria included hoarseness at the time of presentation, history of recent upper respiratory tract infection, or microlaryngeal surgery. Subjects were evaluated while fasting and nonfasting. Each subject was asked about vocal fatigue and ease of phonation. This was followed by acoustic analyses and laryngeal videostroboscopy. Results The incidence of vocal fatigue was not higher while fasting compared to nonfasting ( P = 1.00). Phonatory effort was significantly greater during fasting ( P < .001). Fifty percent of the subjects had an increase in their phonatory effort. There was a significant decrease in the habitual pitch, voice turbulence index, and noise-to-harmonic ratio ( P = .018, .045, and .001, respectively). There were no laryngeal videostroboscopic changes. Conclusion Fasting in males results in an increase in phonatory effort. These phonatory changes may be secondary to dehydration as well as overall neuromuscular fatigability.

Evaluation of laryngeal findings in users of inhaled steroids

The objective of the prospective study is to examine the laryngeal changes by laryngeal videostroboscopy and electromyography (EMG) regarding new-onset dysphonia in asthmatic patients taking inhaled corticosteroids (ICS). Laryngeal changes and electrophysiological status of the laryngeal muscles were evaluated by these methods in 12 patients both at the time of presentation of dysphonia and after cessation of therapy. Laryngeal changes of our patients were mucosal edema, erythema, thickening, adduction deficit, nodule and irregularity in videostroboscopy. Significant correlations were found between laryngeal pathology and dosage and duration of ICS therapy. We detected myopathy by EMG in most of the patients. Also, EMG revealed that cricothyroid muscle was much more affected than thyroarytenoid muscle. In conclusion, we consider that steroid myopathy or mucosal inflammatory theory alone is not sufficient to explain the etiopathogenesis of dysphonia in asthmatic patients taking ICS. The laryngeal mucosal changes were detected by laryngeal videostroboscopic examination in some asthmatic patients, with dysphonia using ICS, and/or laryngeal myopathy was found by laryngeal EMG in some of them in this study. Thus, various factors may have role simultaneously in the occurrence of dysphonia.

Investigation of four distinct glottal configurations in classical singing—A pilot study

This study investigates four qualities of singing voice in a classically trained baritone: "naive falsetto," "countertenor falsetto," "lyrical chest" and "full chest." Laryngeal configuration and vocal fold behavior in these qualities were studied using laryngeal videostroboscopy, videokymography, electroglottography, and sound spectrography. The data suggest that the four voice qualities were produced by independently manipulating mainly two laryngeal parameters: (1) the adduction of the arytenoid cartilages and (2) the thickening of the vocal folds. An independent control of the posterior adductory muscles versus the vocalis muscle is considered to be the physiological basis for achieving these singing voice qualities.

Flexible Laryngoscopy: A Comparison of Fiber Optic and Distal Chip Technologies. Part 1: Vocal Fold Masses

This study was designed to evaluate the usefulness of fiber optic (FO) and distal chip (DC) flexible imaging platforms in the diagnosis of true vocal fold pathology when compared to the gold standard rigid transoral laryngeal telescopic examination. The recorded strobovideolaryngoscopic examinations of 34 consecutive patients were evaluated retrospectively by five raters. All stroboscopy segments were evaluated by two laryngologists, an otolaryngologist, a laryngology fellow, and an otolaryngology resident. Seventeen patients were examined with a high-quality, large-diameter, FO flexible laryngoscope (FO group) and 17 random patients were examined with a DC flexible laryngoscope (DC group). Each patient was also examined using rigid laryngeal videostroboscopy at the same sitting. Examinations of three patients from each group were presented twice to monitor internal consistency. Diagnoses of intrinsic vocal fold pathology made with the flexible laryngoscopes were compared for accuracy to the diagnoses provided using the rigid laryngeal telescope. The ability to make clinical diagnoses via stroboscopy was statistically equivalent with FO technology and DC technology. Rigid examination provided more information than the flexible examination in 27% of the FO examinations and in 32% of the DC examinations. DC technology did not add diagnostic information to the examination when compared to a high-quality, large-diameter, FO endoscope. Rigid endoscopy provides superior images of the true vocal folds and is necessary for precise diagnosis in patients with true vocal fold pathology. Thus, the most cost-effective means of evaluation of voice disorders remains FO flexible endoscopy for dynamic voice assessment and the neurolaryngologic examination followed by rigid stroboscopy for evaluation of the vocal fold edge and mucosal wave. Strobovideolaryngoscopy using high-quality FO or DC flexible equipment should be reserved for patients who cannot tolerate transoral rigid examination, such as children and those with a very strong gag reflex.

Recognizing and Understanding the Limitations of Laryngeal Videostroboscopy

Recognizing and Understanding the Limitations of Laryngeal Videostroboscopy

Blinded Evaluation of the Effects of High Definition and Magnification on Perceived Image Quality in Laryngeal Imaging

Advances in commercial video technology have improved office-based laryngeal imaging. This study investigates the perceived image quality of a true high-definition (HD) video camera and the effect of magnification on laryngeal videostroboscopy. We performed a prospective, dual-armed, single-blinded analysis of a standard laryngeal videostroboscopic examination comparing 3 separate add-on camera systems: a 1-chip charge-coupled device (CCD) camera, a 3-chip CCD camera, and a true 720p (progressive scan) HD camera. Displayed images were controlled for magnification and image size (20-inch [50-cm] display, red-green-blue, and S-video cable for 1-chip and 3-chip cameras; digital visual interface cable and HD monitor for HD camera). Ten blinded observers were then asked to rate the following 5 items on a 0-to-100 visual analog scale: resolution, color, ability to see vocal fold vibration, sense of depth perception, and clarity of blood vessels. Eight unblinded observers were then asked to rate the difference in perceived resolution and clarity of laryngeal examination images when displayed on a 10-inch (25-cm) monitor versus a 42-inch (105-cm) monitor. A visual analog scale was used. These monitors were controlled for actual resolution capacity. For each item evaluated, randomized block design analysis demonstrated that the 3-chip camera scored significantly better than the 1-chip camera (p < .05). For the categories of color and blood vessel discrimination, the 3-chip camera scored significantly better than the HD camera (p < .05). For magnification alone, observers rated the 42-inch monitor statistically better than the 10-inch monitor. The expense of new medical technology must be judged against its added value. This study suggests that HD laryngeal imaging may not add significant value over currently available video systems, in perceived image quality, when a small monitor is used. Although differences in clarity between standard and HD cameras may not be readily apparent on small displays, a large display size coupled with HD technology may impart improved diagnosis of subtle vocal fold lesions and vibratory anomalies.

The clinical usefulness of laryngeal videostroboscopy and the role of high-speed cinematography in laryngeal evaluation

Proper use of laryngeal videostroboscopy aids the otolaryngologist in appreciating vocal fold vibratory patterns and phonatory characteristics. A laryngology practice is incomplete without the application of the stroboscope in diagnosing and tracking treatment progression in patients with vocal complaints. Understanding both the mechanics and the principles of stroboscopy aids in understanding its utility in the diagnosis of laryngeal pathologic lesions. Videostroboscopic parameters evaluated during examination include symmetry, periodicity, glottic closure, amplitude, mucosal wave, and vertical phase differences. Published research has emphasized that videostroboscopic application improves diagnostic accuracy, as compared with traditional methods. High-speed laryngeal cinematography has mainly been a research tool over the years. Improvements in technology with digital imaging have brought it closer to clinical application, as it may have advantages over videostroboscopy in evaluating aperiodic vibratory patterns, visualization of onset and decay of vocalization, and in cases of diplo-or triplophonia.

Post-thyroidectomy superior laryngeal nerve injury.

Voice dysfunction after thyroidectomy may be caused by damage to laryngeal nerves or lesions to strap muscles with laryngo-tracheal movement impairment. Injury to an external branch of the superior laryngeal nerve (EBSLN) is sometimes difficult to recognize clinically and its electromyographic incidence ranges from 0% to 58%. In this study we evaluated, 12-18 months postoperatively, 45 patients who had undergone thyroid surgery (6 total lobectomy, 5 subtotal thyroidectomy, and 34 total thyroidectomy), using a subjective interview, laryngeal videostroboscopy and spectrographic analysis with a multidimensional voice program. Vocal parameters included fundamental frequency, jitter, shimmer, noise-to-harmonic-ratio (NHR) and degree of sub-harmonics. Laryngeal electromyography (LEMG) of the cricothyroid (CT) muscles was performed in 21 subjects with voice problems (35 EBSLNs) using a modified method for the CT recording. In 3 patients of this group (14%) LEMG documented a unilateral EBSLN injury. Easy voice fatigue and decreased pitch range were the most common symptoms after surgery. Average values of vocal parameters pre- and postoperatively in patients without neural damage (n = 42) were: jitter 0.64% and 0.78%, shimmer 3.25% and 3.54%, and NHR 0.12% and 0.13%, respectively (P > 0.05). Acoustic analysis revealed altered patterns in some patients with no objective evidence of damage to EBSLNs, suggesting an extralaryngeal cause of vocal dysfunction, such as laryngo-tracheal fixation or lesions to strap muscles. We conclude that laryngeal videostroboscopy and spectrographic analysis are very useful to assess voice problems after thyroidectomy, including in patients without LEMG-proven neural lesions, in order to suggest early speech rehabilitation, especially in professional voice users.

Effect of mitomycin-C on vocal fold healing in a canine model.

For evaluation of the effect of topical mitomycin-C on vocal fold healing and return of function after surgical excision of mucosa, 6 dogs underwent suspension microlaryngoscopy with bilateral microflap excision of vocal fold mucosa. Topical mitomycin-C, a chemotherapeutic agent and a fibroblast inhibitor, was applied randomly to one side, with the contralateral side serving as the control. Laryngeal videostroboscopy (LVS) was performed on each animal before the operation, at 2 weeks, and before sacrifice at 4 weeks. Both functional analysis with LVS and histologic analysis were performed in a blinded fashion to determine the effect of mitomycin-C on healing. Histologic analysis was augmented with computer morphometrics. The LVS revealed diminished mucosal wave vibration in the vocal folds treated with mitomycin-C, as well as a more atrophic appearance to the vibratory surface. The vocal folds treated with mitomycin-C showed fewer fibroblasts and less collagen within the superficial layer of the lamina propria than the control vocal folds (p < .05, Student's t-test, paired analysis). Inflammatory infiltrate was not significantly different between the two sides. Consistent with the known suppression of fibroblast proliferation by mitomycin-C, the treated vocal folds showed less connective tissue response to the surgical injury. In contrast to the reported positive effects of mitomycin-C on tracheal and glottic stenosis, the observed decrease in the healing response in the present study had negative consequences on the vocal fold vibratory pattern.

Superior laryngeal nerve preservation in peri-apical surgery by mobilization of the viscerovertebral angle

Iatrogenic lesions of the superior laryngeal nerve (SLN) are much more common than is generally recognized. Since injury to this nerve may cause transient or even persistent changes either in quality of voice or in deglutition, an attempt should be made to localize and identify the nerve during surgery. This study included 74 patients who underwent surgical dissection near the thyroid apex in the neck. Effective prevention of SLN injury during surgery was achieved by anatomical localization of the nerve in the viscerovertebral angle and its functional identification with the nerve stimulator. Post-operative analysis consisted of subjective interview, rigid laryngoscopy, acoustic analysis, laryngeal videostroboscopy and cricothyroid electromyography. Four patients complained of post-operative voice changes; two were diagnosed as SLN injury (2.4 per cent), one as reflux laryngitis and the fourth as intubation granuloma. Surgical access to the SLN in the periapical area may be achieved through mobilization of the viscerovertebral angle. The use of a nerve stimulator during difficult situations should keep SLN injury at a minimum.

Allergies and vocal fold edema: a preliminary report.

This paper describes different tools to rule out the etiology of vocal fold edema. A complete voice assessment is used in our Voice Center. This includes patient history, acoustic analysis, laryngeal video-stroboscopy, otolaryngology consultation, allergy testing from our Allergy Clinic, and gastroenterology consultation as appropriate. Inhalant allergy can be a hidden, yet very common cause of chronic laryngitis. Respiratory allergies can also cause decreased pulmonary function; excessive secretions in either the lower airway, trachea, bronchi or in the upper airway of the pharynx; edema of the vocal folds themselves; and unusual resonance characteristics of the pharynx or nasal cavity due to congestion of the membrane in those areas. Voice patients with a history of seasonal hay fever, a history of allergic reactions around cats or dogs, or a strong family history of allergies should be allergy tested. Screening tests for allergies are available, which include a screening radioallergosorbent test or a screening panel of scratch or intradermal skin tests. Once specific allergens are identified, recommendations for therapy or other intervention can be made. Straining the voice, in combination with the above conditions, can increase the voice problem. The histories, allergy test results, and voice laboratory evaluations of several patients are described. Identifying these voice patients and treating their allergies are important in keeping these patients healthy and maintaining a clear, good voice quality. The multidisciplinary approach in voice disorders is indispensable in diagnosis and treatment of these disorders.