Visual Documentation of the Larynx PDF

54 Visual Documentation of the Larynx Robin A. Samlan, Melda Kunduk KEY POINTS otolaryngologist, and both professionals use endoscopy and...

54 Visual Documentation of the Larynx Robin A. Samlan, Melda Kunduk KEY POINTS otolaryngologist, and both professionals use endoscopy and stroboscopy to assess (1) vibratory patterns during various voicing Laryngeal endoscopy, using flexible or rigid endoscopes, conditions, (2) the behavior of the laryngeal and supralaryngeal is used to examine vocal fold structure and gross structures during phonation, and (3) how treatment probes alter function. phonatory physiology. Speech-language pathologists also use endoscopy for visual feedback during therapy for voice, resonance, Videostroboscopy is used to examine vocal fold vibration and laryngeal airway disorders. Because each professional brings patterns and the relationship between the body and the a different perspective to the process, the most thorough examina- cover. tions are typically conducted and analyzed in a team setting. Laryngeal high-speed videoendoscopy complements The first section of this chapter pertains to endoscopy and endoscopy and stroboscopy by showing details of short stroboscopy: assessment protocols, equipment, examination and aperiodic vibration and quantifying vibration technique, and medical records. The second section describes parameters. LHSV, and the third section discusses NBI. Narrow-band imaging uses the tissue’s light-absorption characteristics to show vascular detail. VIDEOENDOSCOPY AND STROBOSCOPY Each vocal fold visualization tool makes a unique contribution to the assessment puzzle. Endoscopy: Assessment Using Continuous Light Several options are available for visualizing and Endoscopic examination with continuous light, as opposed to documenting laryngeal structure and function, and each stroboscopy, provides information about structure and gross has unique advantages and limitations. This chapter movement. Several aspects of laryngeal structure, arytenoid and discusses laryngeal videoendoscopy and stroboscopy vocal fold motion, mucus, vascularity, supraglottal activity, and (LVES), laryngeal high-speed videoendoscopy (LHSV), vocal fold edge shape can be observed. and narrow-band imaging (NBI). Laryngeal Structure Abnormalities and asymmetries of the valleculae, piriform sinuses, epiglottis, aryepiglottic folds, ventricular folds, and posterior glottal The term endoscopy is used here to refer to an examination with rim are noted. Lowered pitch during sustained “ee” widens the a continuous light source and a rigid or flexible endoscope. Laryngeal angle, allowing better visualization of the valleculae. An omega- videoendoscopy provides information about vocal fold structure and shaped epiglottis is a common variant in men, but it is rare in gross function. It is used to diagnose and document voice and women.2,3 Signs of laryngeal irritation or possible laryngopharyngeal laryngeal disorders, plan treatment, make longitudinal comparisons, reflux are noted; these primarily include edema and erythema of educate patients, and provide biofeedback for voice and breathing the posterior larynx, cobblestoning of the posterior pharyngeal therapy. Recording the examination and including still images in wall, interarytenoid bar, and pseudosulcus.4–7 The changes can the medical record are important for routine follow-up and for occur for reasons other than reflux, such as infection, allergies, medicolegal reasons. and mechanical trauma and also occur in well-screened “normal” Stroboscopy is a lighting technique used to examine vocal fold volunteers.8–10 Intra-rater and inter-rater reliability of the findings vibration patterns and the relationship between the vocal fold body is often poor, particularly when rated from flexible fiberoptic and cover. It is valuable for describing mucosal disease and its effect laryngoscopy.9,11,12 on vocal fold vibration. Stroboscopy is necessary to determine glottal closure and mucosal pliability and, sometimes, to identify or differentiate lesions. Rigid and flexible endoscopes can be used Arytenoid and Vocal Fold Motion for stroboscopic evaluations and have different advantages and Movement and position of the arytenoids inform the examiner limitations. about the integrity of the cricoarytenoid joint and the recurrent Laryngeal high-speed videoendoscopy (LHSV) complements laryngeal nerve. Arytenoids are described with respect to their endoscopy and stroboscopy. It allows short and aperiodic vibration mobility and symmetry. Immobile arytenoids are further described to be observed, and analysis procedures provide quantification of by position (e.g., paramedian, intermediate, and lateral) and their vibratory details that is not otherwise possible. axis (e.g., upright and anteromedial rotation). Mobility is most Narrow-band imaging (NBI) is a technique that uses the absorp- easily rated when patients phonate and then rapidly inhale, such tion characteristics of light to enable a detailed analysis of vascular as during “ee”-sniff or coughing. Rapid pitch glide from lowest patterns within and outside a lesion. In the larynx, it has been to highest notes is helpful for observing symmetry of posterior used to improve identification of recurrent respiratory papillo- and lateral pharyngeal wall bulging. Tilting of the petiole during matosis and to screen for malignancies by identifying high-yield the pitch glide might indicate superior laryngeal nerve weakness.13 areas to sample for biopsy. Endoscopic imaging of the larynx and vocal tract is within the scope of practice of both otolaryngologists and qualified speech- Mucus language pathologists.1 Assessment of mucosal health and diagnosis Thickened mucus often adheres to the vocal fold edges or superior of laryngeal pathology are solely within the purview of the surface. The presence of thick mucus generally relates to a lack 808 Downloaded for Andrea Trigueros ([email protected]) at Francisco Marroquín University from ClinicalKey.com by Elsevier on December 02, 2024. For personal use only. No other uses without permission. Copyright ©2024. Elsevier Inc. All rights reserved.  CHAPTER 54 Visual Documentation of the Larynx 808.e1 Abstract Keywords 54 Visualizing the larynx and vocal folds is a key component of laryngeal endoscopy evaluation. In this chapter, laryngeal endoscopy, stroboscopy, videostroboscopy high-speed video endoscopy, and narrow-band imaging are laryngeal high-speed video endoscopy described. The equipment, components of the assessment, and narrow-band imaging protocols are reviewed. voice evaluation Downloaded for Andrea Trigueros ([email protected]) at Francisco Marroquín University from ClinicalKey.com by Elsevier on December 02, 2024. For personal use only. No other uses without permission. Copyright ©2024. Elsevier Inc. All rights reserved.  CHAPTER 54 Visual Documentation of the Larynx 809 of hydration or to chronic irritation from sources such as mechanical narrowing of the epilaryngeal space might help create the singer’s trauma, smoking, or laryngopharyngeal reflux. Mucus pooling in formant,15 and aryepiglottic narrowing or dilation occurs for 54 the pyriform sinuses can indicate poor laryngeal sensation, weak different vowels during connected speech.16–18 lateral pharyngeal walls, or inefficient swallowing. Thickened mucus Other supraglottal movements are clear signs of disorder: tremor adherent to the vocal folds can masquerade as a lesion or mask and myoclonic movement, for example, are evidence of neurologic an abnormality. To allow differentiation of mucus from underlying impairment. Supraglottal constriction is sometimes considered a structures or lesions, patients should be instructed to try to clear normal variant, and other times it is a sign of disordered voice. the mucus by swallowing or with a gentle cough. Constriction occurring with initiation of phonation and mild constriction throughout a production can be normal findings,19,20 whereas sustained supraglottal constriction, as seen in Figs. 54.1 Vascularity and 54.2, is generally indicative of muscle tension dysphonia.16 A blush throughout the vocal fold mucosa is considered erythema Muscle tension dysphonia can be the cause of the voice disorder or hyperemia. Visible capillaries are typically aligned parallel with (primary muscle tension dysphonia), or it may be compensation the free edge; horizontal vascularity is notable. Abnormally dilated for an underlying abnormality (secondary muscle tension dyspho- and tortuous vessels, capillary ectasias or microvarices, might represent nia).21,22 Changing the production target to “oo,” “m,” increasing areas of stiffness or risk for hemorrhage, particularly when they pitch slightly, or phonation on inhalation might decrease the are located along the vocal fold edge. Hemorrhage occurs when constriction enough to achieve vocal fold visualization sufficient enough blood cells have escaped from a vessel to lend a diffuse for teasing apart the etiology. If not, then voice therapy is recom- coloring to the vocal fold. Posthemorrhage vocal folds often appear mended, followed by repeat visualization. yellow brown, similar to healing bruises in other areas. Increased vascularity of the vocal folds, ventricular folds, arytenoids, and epiglottis is common in women during premenstrual days.14 Vocal Fold Edges The degree to which the folds are straight or irregular and smooth or rough should be described.23,24 In addition to describing Supraglottal Activity irregularities related to lesions, indicating whether edges are convex Supraglottal activity refers to motion above the level of the vocal or concave (“bowed”) is necessary. Note that bowing is a descriptive folds. Some supraglottal activity is normal: lateral wall constriction term, not a disorder itself, and bowed folds can be a symptom of is frequently observed with increasing pitch, anteroposterior a number of underlying disorders. A B Fig. 54.1 (A) Vocal folds during respiration. (B) Vocal folds with anteroposterior constriction during phonation. A B Fig. 54.2 (A) Vocal folds during respiration. (B) Vocal folds with lateromedial constriction during phonation. Downloaded for Andrea Trigueros ([email protected]) at Francisco Marroquín University from ClinicalKey.com by Elsevier on December 02, 2024. For personal use only. No other uses without permission. Copyright ©2024. Elsevier Inc. All rights reserved. 810 PART V Laryngology and Bronchoesophagology position, shape, and mechanical properties allow aerodynamic and BOX 54.1 Protocol for Laryngeal Videoendoscopy elastic forces to initiate and sustain vibration. (Continuous Light) Two basic movement patterns underlie most normal and disordered vocal fold vibration. The first is lateral displacement Rest breathing and return to midline, which cyclically opens and closes the airspace Deep breathing between the vocal folds, called the glottis. The second pattern is Easy cough or throat clear a timing difference between the superior and inferior portions of Sustained “ee” at the most comfortable pitch and loudness the vocal folds, so that the inferior portion of the fold leads the Rapid pitch glide from lowest to highest note superior portion in its movement away from and back to midline. Quiet and loud phonation This second pattern is sometimes called a vertical phase difference, Rapid repetitions of “ee” and along with the inertia of the air column just superior to the Rapid repetitions of “hee” vocal folds, it plays an important role in initiating and sustaining The “ee” followed by a quick sniff (×3)a vibration.17,18 Vibration occurs as long as respiratory pressure Whistlinga provides a power source, and intraglottal pressure, the air pressure Sentences and/or conversation as neededa between the vocal folds, is at least partially in phase with the Gentle touch of endoscope to aryepiglottic foldsa velocity of vocal fold movement. In other words, intraglottal Observation of velopharyngeal function during sustained sounds pressure must be high as the vocal folds are separating and low such as “ee” and “s”a as the vocal folds are returning to midline. The driving pressure Observation of velopharyngeal function during sentences loaded asymmetry is facilitated by the vertical phase difference, the with nasal-oral contrastsa inertance of the supraglottal air column, or both.17,18 Alterations a If using a flexible endoscope. to vocal fold structure, occurring with disorders or postoperatively, can significantly affect the vibratory patterns; in the extreme, such perturbations may prevent vibration from occurring at all. The vibrating vocal folds cyclically change the glottal area over time, converting the steady exhaled airstream into a series of air pulses that interact with the subglottal and supraglottal pressures; this is called the glottal flow. The particular pattern Protocol of vocal fold vibration and the influence of the supraglottal air Typical tasks for the endoscopic exam are listed in Box 54.1 and column determine the temporal characteristics of each glottal provide the clinician the opportunity to focus on structure and flow pulse and influence the resultant sound quality. Glottal gross function during a variety of activities. Typical rapid repetition flow and the resultant sound pressure wave are discussed further rate for “ee” and “hee” is four to six syllables per second,2 and in Chapter 55. difficulty with accurate and rhythmic voice onset/offset is common To assess vibration patterns during phonation, where the in neurologic impairment.25,26 Assessment of connected speech fundamental frequency (Fo) of vocal fold vibration is typically (e.g., phrases, sentences, and conversation) is necessary when voice more than 100 cycles per second (Hz), vibration must be observed quality during sustained vowels is inconsistent with symptoms or in slow motion or in what appears to be slow motion. Videostro- what was heard during the patient interview. If there is concern boscopy is used clinically to approximate slow motion for laryngeal about laryngeal sensation, a rough estimate can be gained through and voice evaluation. A stroboscopic light source brightly illuminates observing the patient’s response to gently touching the endoscope the vocal folds across multiple vibratory cycles, and a series of to the posterior aryepiglottic folds. A more precise exam is possible images are captured that highlight the vocal folds at successive using sensory threshold testing (FEESST).27 Examination of phases of the cycle. When the images are presented to the viewer velopharyngeal function is indicated if nasal emission or hypernasal- at the proper rate, the vocal folds appear to be moving and create ity is present. smooth cycles of the vocal folds separating and returning to midline.31–33 The timing of the light flash and image capture is determined by predicting the measurement of current Fo and, if Limitations the prediction is incorrect, the illusion of slow motion vibration Although endoscopy is appealing because of its routine availability will crumble, and the vocal folds will appear to “flutter” rather in otolaryngology clinics, the information it provides is insufficient than vibrate. The strobe light can also be used in a stop or locked to fully understand a voice disorder. Observation of structural mode, where the light flashes at a rate matched with the frequency detail is limited compared to the other techniques, and the vibratory of the vocal fold vibration and creates the illusion that the vocal patterns thought to determine voice quality cannot be observed. folds are not moving at all. Because vocal fold vibration occurs at hundreds of cycles per Stroboscopic assessment is particularly valuable for character- second, specialized lighting or cameras are needed to adequately izing stiffness, scar, or submucosal injury; detecting small vocal visualize vocal fold vibration. fold lesions; identifying asymmetric mass or tension; and monitoring tissue healing after phonosurgery. It has been shown to change the diagnosis in 30% to 47% of patients diagnosed using flexible Assessment With Stroboscopy endoscopy,22,34,35 and it provides additional detail to the original Videostroboscopy is used to assess vocal fold vibration patterns. diagnosis in an additional 32% (e.g., where hyperfunction was Understanding normal vocal fold physiology for different modes indeed present but it appeared as a result of an underlying pathology, of phonation is essential to interpreting stroboscopic examinations. such as atrophy or a lesion).22 Many rating forms are available in A brief description of vocal fold vibration follows, and more detailed the published literature and they include a core set of parameters explanations can be found elsewhere.17,18 Healthy vocal folds are for describing vocal fold vibration patterns and mucosal pliability.36 comprised of a pliable “cover” consisting of the epithelium and Inter-rater and intra-rater reliability vary by parameter and superficial lamina propria and a stiffer “body” consisting of the study.37–39 The Voice-Vibratory Assessment with Laryngeal Imaging intermediate and deep lamina propria and thyroarytenoid Form (VALI)24 appears to improve relatability of ratings by muscle.28–30 Muscle contraction is responsible for positioning incorporating parameter definitions, rating notes, and graphical (adduction and abduction to and from midline) and shaping depictions of each parameter into the rating form. Regardless of (lengthening, shortening, and bulging) the vocal folds. Adequate the rating scale used, the following parameters should be assessed. Downloaded for Andrea Trigueros ([email protected]) at Francisco Marroquín University from ClinicalKey.com by Elsevier on December 02, 2024. For personal use only. No other uses without permission. Copyright ©2024. Elsevier Inc. All rights reserved.  CHAPTER 54 Visual Documentation of the Larynx 811 Hourglass-shaped gaps (see Fig. 54.3E) are common with Regularity bilateral lesions, such as vocal nodules, or a unilateral lesion with 54 Regularity, or periodicity, describes the degree to which the time a contralateral reactive lesion. Large unilateral lesions can also it takes to complete one phonatory cycle is similar to the time it cause hourglass-shaped gaps. An incomplete closure pattern occurs takes to complete the next cycle.28 Regularity is best assessed in when the gap extends the entire length of the folds, and is common the stop mode, where the image appears static if vibration is regular, with vocal fold motion impairment, scar, and one variant of muscle and it quivers if vibration is irregular. It can also be estimated tension dysphonia/aphonia. Sometimes closure alternates between from the strobe mode in that the strobe light will not adequately two or more patterns, and multiple patterns should be delineated track fundamental frequency if vibration is irregular, and the image when that occurs. quivers or blurs. Aperiodicity is more common in older adults than younger adults.40 Regular vibration depends on a steady balance between pulmonary pressure and the vocal folds. Irregular Phase Closure vibration can be caused by a variety of factors that include asym- The previous section describes terminology indicating the degree metries of innervation (e.g., paresis), homogeneity (e.g., lesion of closure, and it is also useful to describe the duration of closure. such as cyst or carcinoma), flaccidity (e.g., paralysis, atrophy, and The glottis is typically open (opening, fully open, or closing) for edematous lesion), unsteady tonus (e.g., spasmodic dysphonia or approximately two-thirds of one vibratory cycle during vibration other neuromuscular disease), or inconsistent force (e.g., functional at MCPL. Closed time generally decreases with higher pitches. pulmonary disease).28 Importantly, evaluation of other stroboscopic It might increase or decrease in older adults, though findings vary parameters will not be accurate if vibration is aperiodic. across studies.3,45–47 Phase closure is a useful measurement in a patient who sounds breathy but achieves complete closure. It also explains one type of hyperfunction, when the vocal folds open Glottal Closure only briefly during each cycle. Closure pattern indicates the degree and pattern of vocal fold contact at the most closed instant of the vibratory cycle. Two principal questions should be addressed: First, is the glottis completely Vertical Closure Level closed or not completely closed? Second, if the vocal folds are The vocal folds typically meet on the same vertical plane. Off-plane not completely abutting one another, what is the shape of the closure can occur secondary to neuromuscular differences between remaining gap? Gap shapes and incomplete closure patterns can the folds (paralysis or paresis) or as a result of laryngeal trauma be described using a variety of terms, and one such scheme is or surgery. A level difference can significantly impact the glottal shown in Fig. 54.3. As stated, closure is traditionally rated at flow and voice quality. most comfortable pitch and loudness (MCPL), and it is common for closure to become more complete with low pitch or loud phonation and to become less complete with high pitch and quiet Mucosal Pliability and Stiffness phonation. Amplitude of vibration, each fold’s horizontal excursion from midline, Complete closure (see Fig. 54.3A) is the most common is one aspect of pliability/stiffness. Excursion of approximately pattern for men,41 and it occurs in some women at MCPL or one-third of the width of the fold (Fig. 54.4) is considered normal.28 with increased loudness.41–43 A posterior gap (see Fig. 54.3B) is The maximum vibratory amplitude of the left and right folds is the most common closure pattern for women,40,41,44 and it might generally symmetric, smaller in women than men, generally covaries be a normal variant for men.41 The gap is typically limited to the with loudness, and varies inversely with pitch.3 Decreased amplitude space between the cartilaginous folds during MCPL, but it can of vibration can be the result of glottal incompetence, tight glottal extend into the membranous folds during quiet productions.41 closure, or increased vocal-fold mass or stiffness. Decreased A gap extending into the membranous larynx during phonation amplitude is common in lesions such as firm polyps, cysts, papilloma, at MCPL is considered a laryngeal isometric pattern of muscle carcinoma, Reinke edema, scarring, and hyperfunction.28 Increased tension dysphonia.16 amplitude may be a sign of decreased tonicity, as observed in vocal Anterior (see Fig. 54.3C) and spindle-shaped gaps (see Fig. fold paresis or atrophy. 54.3D) are normal variants in men of any age and in older Mucosal wave is the vertical upheaval of the vocal fold cover women.2,40 They are also present in patients with disordered voices over the vocal fold body. It occurs because of the vertical phase and can occur with tissue deficit of the membranous folds as a shift, the timing difference between the upper and lower margins result of scarring, prior surgery, atrophy, vocal fold motion impair- of the vocal folds that is vital to the self-oscillation of the folds.17,18,48 ment, superior laryngeal nerve deficit, or sulcus vocalis. The wave is propagated from the inferior edge of the vocal fold, A B C D E Fig. 54.3 Glottal closure and gap patterns. (A) Complete closure. (B) Posterior glottal gap. (C) Anterior glottal gap. (D) Spindle-shaped gap. (E) Hourglass-shaped gap. Downloaded for Andrea Trigueros ([email protected]) at Francisco Marroquín University from ClinicalKey.com by Elsevier on December 02, 2024. For personal use only. No other uses without permission. Copyright ©2024. Elsevier Inc. All rights reserved. 812 PART V Laryngology and Bronchoesophagology A B Fig. 54.4 (A) Complete glottal closure. (B) Maximum amplitude of vibration/excursion. and then it travels up the medial edge and across the superior surface of the fold. The velocity of the mucosal wave is related BOX 54.2 Protocol for Laryngeal Videostroboscopy to the amount of pressure needed to establish phonation,49,50 and (Xenon Light) we judge mucosal wave as the distance it travels across the superior surface of the fold. In a healthy system at MCPL, this wave travels RIGID ENDOSCOPE across approximately half the width of the vocal fold.51 The mucosal Sustained “ee” at patient’s most comfortable pitch and loudness wave travels farther across the fold when mucosa is abnormally (several times) pliable, as in polypoid degeneration or with increased subglottal Phonation of the “ee” on inhalation air pressure. As such, it is normally greater than half of the width Glide midrange to high, sustaining the high note of the fold for loud phonation, when subglottal air pressure Glide midrange to low, sustaining the low note is increased. Mucosal wave is decreased or even absent when Quiet “ee” the mucosa is stiff or when the differentiation of the vocal fold Loud “ee” layered structure is minimal; this occurs normally with increasing Sustained “ee” at the patient’s most comfortable pitch and pitch28 and with aging.40 In pathologic conditions, decreased loudness using locked mode or absent mucosal wave occurs with some lesions, scarring, and Trial therapy as needed sulcus vocalis. Incomplete glottal closure that results from aging, FLEXIBLE ENDOSCOPE atrophy, or motion impairment can also lead to decreased or absent Consensus Auditory Perceptual Evaluation for Voice57 sentences: mucosal wave.40,52,53 “The blue spot is on the key again.” “How hard did he hit him?” Symmetry “We were away a year ago.” Phase symmetry is a timing parameter. It refers to the extent to “We eat eggs every Easter.” which the vocal folds mirror each other during vibration. The “My mama makes lemon muffins.” vocal folds should depart from and arrive back to midline at the “Peter will keep at the peak.” same time as one another. Asymmetric vibration raises questions Singing tasks as necessary about differences in the mechanical properties or neurologic status Conversation as necessary of the folds,28 and left-right differences in position, mass, tension, elasticity, and viscosity should be further explored. Altering the left-right symmetry does not necessarily alter perceived voice quality,54,55 however, and mild left-right asymmetry has been identified in almost 80% of control subjects with normal voice lengthening of the folds during ascending pitch glides confirms quality.56 grossly intact cricothyroid muscle function, and sustained high-pitch phonation highlights midmembranous edema and stiff or scarred segments along the edge. The locked mode is useful for assessing Protocol vibratory regularity, which is the extent to which one vibration Stroboscopic parameters are traditionally rated from sustained cycle is similar in duration to the next. It is also useful for highlight- phonation at MCPL, although a more thorough sample video- ing lesions of the vocal fold edge and differences in the vertical stroboscopy protocol is listed in Box 54.2. Vibratory parameters plane of the two vocal folds. are rated from phonation of “ee” at the MCPL, so the examiner If the patient’s concern does not manifest during sustained should elicit several of these productions, monitoring voice quality phonation, the flexible endoscope is used to assess connected during the examination. If the quality during stroboscopy is dis- speech. The sentences included in the Consensus Auditory Per- similar to conversational quality, additional productions should ceptual Evaluation for Voice57 are a good standard sample, because be elicited when possible. Phonation on inhalation can decrease they encourage a variety of different speech sound contexts and supraglottal constriction, which is useful when the ventricular have differing laryngeal motor control requirements. If the patient folds limit visualization of the vocal folds,16 and the task highlights is concerned with their singing voice, singing tasks must be included edema or lesions of the inferior compartment of the vocal fold in the examination. Trial (probe) therapy techniques are used to edge. Vibratory patterns should change for high and low pitch alter muscle tension or vibratory patterns to achieve a more accurate and for quiet and loud phonation. Bilateral and symmetric diagnosis, and the results help the speech-language pathologist Downloaded for Andrea Trigueros ([email protected]) at Francisco Marroquín University from ClinicalKey.com by Elsevier on December 02, 2024. For personal use only. No other uses without permission. Copyright ©2024. Elsevier Inc. All rights reserved.  CHAPTER 54 Visual Documentation of the Larynx 813 make decisions regarding how to approach voice therapy and the This type of endoscope provides a wider viewing angle, and a patient’s prognosis for improvement with behavioral treatment. longer lens or a zoom lens might be needed to magnify vocal fold 54 There are many such techniques. Humming, twang, breath cues, details for accurate observation. sighs, or descending glides with high airflow can alter supraglottal Defogging endoscopes can be a challenge, because sterilizing postures, the glottal closure pattern, and the vocal fold vibration. beads can damage the lens and injure the patient. Alternatives Trills, breathy voice, flow phonation, coughing, pushing, abdomi- include liquid defogger, hot (not boiling) water, soap film, surgical nodiaphragmatic onsets, and visual feedback are also useful for wax, and holding the endoscope lens briefly against the patient’s evaluation. cheek or the side of the tongue. The examination is generally tolerated without topical anesthesia, but a small amount of ben- zocaine topical spray or a similar product is sometimes useful and STROBOSCOPY SYSTEMS does not appear to affect examination results.59 Videoendoscopy and stroboscopy systems can be purchased as a complete unit, or they can be assembled by the end user. A complete system includes light sources bright enough for endoscopy and Flexible Endoscopes stroboscopy, rigid and flexible endoscopes, a camera and lens, a The primary advantage of the flexible endoscope is the ability to monitor, a computer for digital recording, a contact microphone view the larynx dynamically—that is, during natural functions or electroglottograph for determining Fo, and a printer. Many such as speech and singing. Arytenoid mobility and the glottal choices are available for each part of the system and should be gap can be accurately described,42 and the nasal cavity and velo- selected to best meet the users’ needs. A variety of rigid and flexible pharyngeal port can be assessed during the same examination. endoscopes are available; these will be described in more detail Flexible endoscopy is preferred when the question is one of in the following paragraphs. Cameras can be digital or high defini- movement rather than structure or mucosal health. It is particularly tion, and some require specific image processors. Recordings can useful for disorders such as spasmodic dysphonia and muscle-tension be standard or high definition, and viewing options, which include dysphonia, in which the voice problem is more obvious during real time and playback, can be customized to meet the users’ needs connected speech than in sustained vowels. The disadvantages are and budget. Software for retrieval and playback of previously that light transport and magnification are inferior to rigid endos- recorded examinations varies for different systems, and some copy; distortion occurs at the periphery of the image, and a moiré systems provide options for review of images and videos from any or honeycomb effect can occur when the image is focused. The networked computer utilizing the facility’s network infrastructure. honeycomb effect is not a concern with flexible endoscopes that These options are discussed in additional detail in the section on contain a charged-coupled device (CCD) camera in the tip. These medical records. “chip-tip” endoscopes eliminate the fiberoptic bundle and provide superior optics. Newer high definition chip-tips are also available and the difference in image quality can be seen in Fig. 54.5. Endoscopes Although the chip-tip endoscope represents a significant improve- ment over fiberoptic scopes, the new technology comes at a Rigid Endoscopes significant cost increase, and the quality of resultant examinations Both 70- or 90-degree endoscopes can be used with clinical is not equal to that achieved with rigid endoscopy. In addition, laryngeal imaging systems. Rigid scopes provide higher resolution many patients find the flexible examination to be more invasive than flexible ones and provide brighter, clearer pictures. Contrast than the rigid examination, and the flexible technique carries the is excellent, the selection of viewing angles is large, and the image risks of nosebleed, adverse reactions to the anesthetic, and vasovagal is more accurately magnified than with a flexible endoscope. The reaction. Flexible endoscopes can be purchased in varying channel examination is simple and does not usually require topical anes- and distal tip diameters and working lengths, and they are available thesia.16,28,58 Small diameter (6 mm outer diameter) endoscopes with or without a working channel. are available and can improve exam tolerance for children and adults with anxiety. The primary limitation of the rigid endoscope Technique. The flexible endoscope is typically inserted after the is that speech production is limited to sustained vowels, most application of a topical anesthetic and a vasoconstrictor. It can be commonly “ee,” which complicates assessment of disorders that passed through the inferior or middle meatus of the nose. The are more apparent in connected speech. Because visualization with superior path is preferred for examination of the velopharyngeal a 70-degree rigid endoscope usually requires an extended neck port, but the paths are equivalent for visualizing the larynx. The and protruded tongue, the size of a glottal gap might appear examiner should raise the endoscope slightly, as the patient exaggerated,42 and in some patients, it is difficult to accurately swallows, to avoid triggering a cough or laryngeal closure reflex, assess arytenoid motion. which can occur if the endoscope touches the rising larynx during a swallow. Technique. The laryngeal examination with a 70-degree rigid endoscope is conducted with the patient bending slightly forward from the hips while maintaining a straight back. The neck and Troubleshooting chin are extended, and the tongue is slightly protruded. The A quality examination, with either a rigid or flexible endoscope, examiner wraps the tongue in gauze and holds it gently during means that the image is in focus, it is large enough to show small the examination. The endoscope is advanced just under the uvula mucosal irregularities, and it is bright enough to show details but or between the uvula and faucial pillars until the epiglottis is not so bright as to obscure them. Contrasting color is important visualized. The examiner might need to flex the wrist to tilt the for differentiating subtle lesions and vascular changes. Ideally, an endoscope tip inferiorly; the angle can be varied for differing examination includes both a wide-angle view of the larynx and a levels of magnification and differing fields of view. Sometimes close-up view of the vocal folds. Common imaging problems and closing the mouth down around the endoscope improves the view. solutions are listed in Table 54.1. Other trouble-shooting tips are provided in Table 54.1. Examination with the 90-degree endoscope is similar, but the patient does not need to bend forward or extend the neck. Another difference is Medical Records the angle; the tip of the 90-degree scope is positioned with minimal Some medical records systems provide a built-in database that tilt so that the light is parallel to the surface of the vocal folds. allows easy storage and retrieval of patients’ laryngeal endoscopic Downloaded for Andrea Trigueros ([email protected]) at Francisco Marroquín University from ClinicalKey.com by Elsevier on December 02, 2024. For personal use only. No other uses without permission. Copyright ©2024. Elsevier Inc. All rights reserved. 814 PART V Laryngology and Bronchoesophagology TABLE 54.1 Common Problems and Solutions for Laryngeal Endoscopy and Stroboscopy Problem Solution(s) The image is foggy. Warm the endoscope. As needed, clean the lens of the endoscope, eyepiece, or camera. Turn the endoscope so that the lens is facing the cheek during insertion. The image is fuzzy. Check or adjust the focus. As needed, clean the lens of the endoscope, eyepiece, or camera. The image is dark. As needed, clean the lens of the endoscope, eyepiece, or camera. Increase light as recommended for the particular system. Reposition the endoscope. Check the number of hours on the xenon bulb (its brightness fades with use). The image is grainy. Decrease the gain. Slightly defocus the endoscope. Consider a shorter camera lens. The image is tilted, or the vocal folds appear to Modify the alignment of the endoscope and camera. have different widths. Be sure your arm and wrist are straight when approaching the patient. Decrease the pressure on the laryngeal microphone on the thyroid cartilage. The image is mostly of the valleculae and Insert the endoscope farther. epiglottis, or the anterior commissure cannot Tilt the tip of the endoscope down. be seen. Have the patient close his or her mouth around the endoscope. Check the patient’s position: legs should be uncrossed, back straight, and neck slightly extended. Start with a high-pitched “ee.” Mostly arytenoids and posterior vocal folds are Withdraw the endoscope slightly. seen. Tilt the tip of the endoscope down. Have the patient phonate in a high pitch. Request the production be closer to an “ee.” The base of the tongue is high. Start with a “hey,” sustaining the “ee” part of the diphthong. Ask the patient to allow the back of the tongue to be “floppy.” Have the patient hold his or her own tongue. The uvula is “in the way.” Direct the endoscope around the uvula. Request the production be closer to an “ee.” Have the patient pant. Have the patient plug his or her nose or use nose clips. The color is abnormal. The color control is system specific; consult your manual. Check the brightness settings. Check the focus; slight defocusing might be needed. The epiglottis is omega shaped. Use a 90-degree endoscope. Have the patient bend farther and extend the neck more. Try a lateral approach. The strobe is “not tracking.” Modify placement of the laryngeal microphone or electroglottograph electrodes. Have the patient take a big breath and phonate louder or quieter. Try additional pitches. If possible, select an approximate fundamental frequency as an override. Plica ventricularis: ventricular folds are closed so Ask the patient to sigh a soft, gentle, breathy “hhheee.” the true vocal folds cannot be seen. Ask the patient to laugh “hee hee hee.” Request phonation on inhalation. Perform voice therapy, and then repeat the evaluation. Gagging occurs. Reduce anticipation through education about the examination. Talk the patient through the examination in a calming voice. Distract the patient by having him or her think the alphabet backward. Have the patient focus on a spot without blinking. Ask the patient to keep the tongue protruded and to pant when breathing in. Have the patient hold his/her own tongue. Alter the approach (e.g., lateral vs. anterior; elevate or lower the endoscope tip). Apply topical anesthetic. Use a flexible endoscope. and stroboscopic examinations. Multiple stroboscopy units can be linked using a central server so that videos can be accessed LARYNGEAL HIGH-SPEED VIDEOENDOSCOPY from remote locations. Images can be printed or saved electronically Videostroboscopy is one of the most frequently used visualization as part of a report. Report templates can be prepared for different techniques of vocal fold vibration and works well when vibration procedures, such as transnasal esophagoscopy or stroboscopy, and is fairly periodic.28,52 Unfortunately, it works poorly, or not at all, reports can be attached to electronic medical records. Laryngeal when vibration is irregular. Irregular vibration is common in endoscopic images and videos can also be archived over the hospital disordered voice production and during short phonatory events, network using the Digital Imaging and Communications in limiting stroboscopic assessment of some patient productions, and Medicine standard. Several vendors have incorporated this process components of phonation such as onset and offset. into their systems for documenting and reporting endoscopic Currently, only LHSV60–62 and high-speed kymography63–65 and stroboscopic findings. Capabilities for integrating images have sufficient temporal resolution for observing vocal fold vibration and electronic medical records are ever-evolving and should be regardless of phonatory duration or severity of dysphonia. Both considered when purchasing equipment (Videos 54.1 to 54.9). techniques capture images much faster than the vibration rate of Downloaded for Andrea Trigueros ([email protected]) at Francisco Marroquín University from ClinicalKey.com by Elsevier on December 02, 2024. For personal use only. No other uses without permission. Copyright ©2024. Elsevier Inc. All rights reserved.  CHAPTER 54 Visual Documentation of the Larynx 815 54 A B Fig. 54.5 Image quality with flexible (A) high-definition chip-tip and (B) standard chip-tip scope. 1.Ln  141 192 320 A B 0.160s (320) Fig. 54.6 Kymographic images (A) taken on line (Ln) 141 from endoscopic high-speed digital imaging (B) from frames 192 to 320 show initiation of vocal fold vibration during phonation in a normal voice. Note the number of vocal fold oscillations and detail before the first vocal fold contact compared with those in Fig. 54.7. the vocal folds so that detailed information of every vibration promise for clinical applications. These recordings have provided cycle is collected. Kymography can be considered a one-dimensional the foundation upon which much of our subsequent knowledge version of LHSV in that it shows movement of a single horizontal of vocal fold vibration is based. Technologic advances in cameras, line from a laryngeal image while LHSV allows the observation image resolution, and computers have resulted in development of the full length of vocal folds. Figs. 54.6 and 54.7 demonstrate of LHSV, which permits recording of 2000 to 10,000 (and higher) the advantage of generating kymograms from LHSV in comparison frames per second (fps) as opposed to the 25 or 30 fps available to stroboscopy. in videostroboscopy. This technique holds great promise for As the first recordings of vocal fold vibrations were made with overcoming the limitations of currently available techniques for high-speed photography,66–68 high-speed recordings have shown direct observation of laryngeal function. Videos 54.1 to 54.12 Downloaded for Andrea Trigueros ([email protected]) at Francisco Marroquín University from ClinicalKey.com by Elsevier on December 02, 2024. For personal use only. No other uses without permission. Copyright ©2024. Elsevier Inc. All rights reserved. 816 PART V Laryngology and Bronchoesophagology 1.Ln  173 a flexible endoscope.70–73 A 300-watt cold light source is used to 188 achieve sufficient clarity and brightness of LHSV images using rigid and flexible endoscopes, though a lower frame rate must be used to achieve good images with the flexible (2000 fps,72,73 3000 fps,71 or 4000 fps70). The use of an LHSV system requires research- ers to make trade-offs among capture rate, length of recording, 252 color, image size, computational time, storage space, and analysis. A LHSV systems, for example, may permit a faster capture rate for a longer sample duration in color, but with a trade of a smaller image size. LHSV images at the highest capture rates are most often in black and white. Note that the custom LHSV systems allow simultaneous recordings of the endoscopic and acoustic signals and permit later analysis and comparisons of endoscopic and acoustic data. Assessment of Vocal Fold Vibration Some of the parameters used in perceptual evaluation of high-speed image data analysis are the same as those for LVES: closure pattern, phase symmetry, amplitude of vibration, mucosal wave, pliability of tissue, adynamic segments, symmetry, regularity, vertical closure level, and vocal fold edges. The VALI24 includes a section for visual perceptual ratings of LHSV parameters. In spite of its limitations, there will likely be a role for LHSV assessment in clinical settings when the technology is available. Patel and col- B leagues74 reported that assessment of vocal fold vibratory function via stroboscopy was not possible in 63% of their study sample, Fig. 54.7 Kymographic images (A) taken on line (Ln) 173 from yet assessment using LHSV was possible for all participants. laryngeal videoendoscopy and stroboscopy (B) from frames 188 to Zacharias et al. reported a 7% change in the diagnosis and manage- 252 show initiation of vocal fold vibration during phonation in a normal ment of vocal fold pathology when LHSV was used in addition voice. Note the number of vocal fold oscillations and detail before the to LVES.75 Powell and colleagues (2016) simulated stroboscopy first vocal fold contact compared with those in Fig. 54.6. from LHSV, deriving the glottic cycle directly from the changing glottal area. They found the simulated stroboscopy had fewer asynchronous image sequences than the acoustic-based LVES, and inter-rater reliability was higher for the simulated stroboscopy.76 show examples of stroboscopy and LHSV for individuals with As indicated, “high-speed” includes many different frame rates and without voice disorders. and the rate selected will impact the reliability of ratings and measures of vocal fold vibratory features.77,78 Image degradation to 5333 fps did not alter the clinical assessment, yet degradation Equipment to 2000 fps changed the perceptual ratings of 16% of the samples There are no LHSV systems currently commercially available, analyzed. The resulting recommended minimum rate for laryngeal ready to be used in clinic settings. End users must combine imaging is 4000 fps.77 components to build a system for their use. However, there are LHSV also allows the observation of phonation onset and several user-friendly LHSV systems that are still in use at various offset,79,80 vibration in the surrounding structures such as ventricular research sites, including the KayPENTAX Color High-Speed Video folds,81 intermittent vibration breaks, asymmetry between right System, model 9710 (KayPENTAX, Montvale, NJ), and the Wolf and left vocal fold vibration, and differences in frequency of High-Speed (Richard Wolf Medical Instruments, Vernon Hills, vibration along different portions of the same vocal fold.82 IL). The KayPENTAX system has a spatial resolution of 512 × The primary challenge in analyzing high-speed images has 512 at 2000 fps, 512 × 256 pixels at 4000 fps, and 512 × 96 pixels been managing the vast amount of data generated (a 2-second at 10,000. The Wolf Endocam 5562 has spatial resolution of 256 recording requires ∼90 MB of digital storage).66–68 The analysis × 256 pixels at 4000 fps. Their sample duration varies from 2 to has been mostly perceptual, and reviewing the whole captured 4 seconds. As a frame of reference, the spatial resolution of the phonation segment could take a long time, depending on the KayPENTAX High-Definition Digital Stroboscopy System is capture rate. Advances in computer processing speed, storage 1920 × 1080 pixels and there is no limit to the sample duration. capacity, and image-processing techniques83–85 have helped address Other research laboratories set up custom LHSV systems using some of the aforementioned issues related to LHSV. The Quick more powerful cameras. For example, the Phantom v7.3 high- Vibratory Profile software86 provides a quick overview of LHSV speed camera (Vision Research, Wayne, NJ) records at 10,000 data and allows rapid identification of the best video segments fps and higher with a spatial resolution of 640 × 480 pixels and for perceptual and objective analyses, shortening the viewing time sample duration of 32 seconds. At full resolution (800 × 600 for the LHSV recording. Current image-processing techniques pixels), maximum speed is 6688 fps.31 A powerful LHSV system (e.g., Phonovibrogram85) allow rapid and objective data analysis like this one is primarily a research tool because of equipment and introduce easily recognizable visual representations of vocal size, the quantity of the data acquired, the amount of time it fold vibratory patterns in normal and disordered voice produc- takes to review the captured data, and the complexity of image tion.87,88 The Wolf system includes an automated image-processing processing. Several other custom-made LHSV systems exist and system that provides quantitative information regarding right and are being used to investigate the vocal fold vibratory function in left vocal fold asymmetry and the glottal perturbation measures research settings.31,69 (e.g., open quotient, speed quotient, jitter, and shimmer). Additional LHSV is typically completed using a rigid endoscope, though image-processing systems are used to process LHSV data in several laboratories have successfully reported use of LHSV with research settings, but these are not commercially available at this Downloaded for Andrea Trigueros ([email protected]) at Francisco Marroquín University from ClinicalKey.com by Elsevier on December 02, 2024. For personal use only. No other uses without permission. Copyright ©2024. Elsevier Inc. All rights reserved.  CHAPTER 54 Visual Documentation of the Larynx 817 time. Several methods of visual representation of high-speed than adult men.98 The findings indicate that we cannot extrapolate videoendoscopy data have been proposed. Some of these include from adult data to understand how children’s vocal folds vibrate. 54 the Nyquist plot,84 digital kymography playback, and mucosal LHSV has also been used to determine that hormone fluctuations wave kymography playback.56 observed across the menstrual cycle do not appear to have direct effect on vocal fold vibratory characteristics in young women with no voice concerns.99 The findings provide new insights Limitations about the long-debated effects of hormonal changes on vocal fold Many challenges prevent LHSV from replacing LVES as a clinical vibration. Several different analyses of LHSV data were performed tool: the short duration of the recording; prolonged saving time to show how vocal fold vibration in people with vocal fold paralysis of the captured images, which will lengthen the examination session differed from those with normal voice. Those with vocal fold if the tester wishes to obtain several phonation tasks in one session; paralysis presented with differences in amplitude symmetry, lack of synchronized audio playback; decreased spatial resolution; mucosal wave, frequency, phase, open quotient, and speed index no medical insurance billing code for the procedure; and cost. in addition to glottic closure patterns.100 Chen, Woo, and Murry Image distortion secondary to the distance between the endoscope (2017)101 measured digital kymography from LHSV recordings and the vocal folds, the endoscope angle, or movement of the to demonstrate that despite improvement of the pathologic fold endoscope during the image-capturing process is inherent to any vibratory behavior with surgical treatment of polyp, paresis, endoscopic procedure and makes comparison of images taken paralyses, and scar, the pattern was still different from that of the from different visits difficult. The calibration issue has been normal vocal fold’s vibration. The vocal fold vibratory behaviors addressed by the development of a laser projection system,89 but at the initiation102–104 and termination102,103 of voice are also laser projection is not available with the current LHSV systems. becoming of great interest to demonstrate the tissue pliability Each of the image-processing systems84,85 can compensate for some and health in investigating vocal function in vocal health and of the endoscope movement during the imaging. The examiner’s disease processes. endoscopic skills, training, and understanding of the LHSV It appears that quantitative analysis of LHSV will further our technique further improve the quality of the data collection and understanding of the voice source and biomechanics of vocal analysis. In addition, the parameters used to rate vocal fold vibration fold vibration. Once the aforementioned technical limitations are still being refined. Research that shows firm evidence for the are overcome and following further evidence of the relevance clinical relevance of LHSV is in its infancy, but it is emerging. of perceptual and objective/quantitative LHSV parameters to Only when standard parameters and normative data are identified assessment of vocal function, LHSV is poised to become an will the added benefit of observing cycle-to-cycle vocal fold excellent tool to show the efficacy of medical, surgical, and vibration be realized in a clinical setting. behavioral interventions for voice disorders in a clinical setting (Videos 54.10 to 54.15). Applications Results of studies using LHSV have already improved our under- NARROW-BAND IMAGING standing of normal and pathologic voice production. Kiritani and NBI is considered one of the “biologic endoscopy” techniques.105 colleagues90,91 found that, during diplophonia, the left and right Initially developed to improve the recognition of Barrett esophagus vocal folds vibrate at different frequencies, and the phase difference at the squamocolumnar junction of the lower esophageal sphinc- between the movements of vocal folds varies with time. Lindestad ter,106,107 NBI takes advantage of the absorption characteristics and associates81 used LHSV techniques to study the relationship of light and the differential absorption characteristics of tissues between ventricular fold vibration, vocal fold vibration, and voice to highlight mucosal and submucosal vascular structures. Blue quality. Patel and colleagues92 demonstrated that LHSV can help light, with its shorter wavelength, is better absorbed by hemo- differentiate between adductor spasmodic dysphonia and muscle globin. Mechanical light-filtering technology passes only the tension dysphonia, which has not been possible with stroboscopy. blue subset of the white light spectrum so that structures with Ahmad, Yan, and Bless45 showed a variety of vocal fold vibratory high hemoglobin concentration become more apparent and patterns in young females with normal voices. the clinician can visualize the tissue’s vascular pattern.108 This Subjective perceptual evaluation of LHSV exams has been creates a sharp contrast for good visualization of fine mucosal disappointing. For example, subjective evaluation failed to identify detail and helps identify subtle microvascular abnormalities pathology-specific parameters for distinguishing between vocal (Figs. 54.8 and 54.9). fold vibration in adductor spasmodic dysphonia and vocal tremor.93 In the larynx, NBI provides surgeons with information about Quantification of subtle differences in vibratory characteristics submucosal vascular patterns under leukoplakia109 and improves and demonstration of their relevance to perceived voice quality the yield of biopsies in laryngeal110 and hypopharyngeal111 lesions are needed. It is possible that quantitative analysis of LHSV will by directing the examiner to the more “suspicious” areas. Ni and be useful in demonstrating the effects of neurologic diseases, such colleagues112 suggested a classification of microvascular abnor- as spasmodic dysphonia and vocal tremor,94 on vocal fold vibration, mality patterns in the larynx and reported 89% sensitivity, 93% possibly helping with the differential diagnosis. LHSV has also specificity, 91% positive predictive value, 92% negative predictive been used to investigate different singing styles and their effects value, and 90% accuracy in making a correct diagnosis. Lin and on laryngeal configuration.95,96 colleagues113 reported a significantly higher accuracy of NBI Quantitative analysis of LHSV has provided important detail over white-light endoscopy in detecting second tumors in the about vocal fold vibration in several populations, leading to insights oropharynx and hypopharynx. The European Laryngological about normal and disordered production. Several examples follow. Society (ELS) proposed a protocol to classify laryngeal vascular Measures of vocal fold vibration differed between older adults with changes that is simpler than the Ni et al. (2011) classification.114 and without age-related dysphonia (ARD), yet there was consider- In one study, this classification system yielded 100% sensitiv- able overlap in some measures. The findings provide evidence ity, 95% specificity, 100% positive predictive value, and 96% that normal and atypical aging voice exists on a continuum of negative predictive value.115 NBI has also been used in diagnosis health and disease, with some aspects of vibration in common of recurrent respiratory papillomatosis.113,116 The ELS classifi- and others separating the two conditions.97 Quantitative LHSV cation system has been shown to differentiate papilloma from analysis was used to show that amplitude and time periodicity, malignant lesions based on the angle of the turning points for phase asymmetry, and glottal gap are more variable in children perpendicular changes.115 Downloaded for Andrea Trigueros ([email protected]) at Francisco Marroquín University from ClinicalKey.com by Elsevier on December 02, 2024. For personal use only. No other uses without permission. Copyright ©2024. Elsevier Inc. All rights reserved. 818 PART V Laryngology and Bronchoesophagology A B Fig. 54.8 True vocal fold scar at the anterior commissure. (A) White light imaging. (B) Narrow-band imaging. A B Fig. 54.9 Carcinoma in situ of the left true vocal fold. (A) White light imaging. (B) Narrow-band imaging. coherence tomography.118 Applicability of these techniques to EMERGING TECHNOLOGIES clinical evaluation of vocal fold vibration has not yet been Other exciting emerging imaging techniques are being used in determined. the laboratory to study vocal fold vibration. Two promising technologies include depth kymography117 and dynamic optical For a complete list of references, visit ExpertConsult.com. Downloaded for Andrea Trigueros ([email protected]) at Francisco Marroquín University from ClinicalKey.com by Elsevier on December 02, 2024. For personal use only. No other uses without permission. Copyright ©2024. Elsevier Inc. 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