Roger C. Nuss
A child's voice changes throughout childhood, both due to normal physiologic development as well as from various pathologic conditions that may affect the vocal folds. Though many of these conditions are benign, it is important for the clinician to recognize if a child's voice is significantly deviated from the norm, and pursue an appropriate evaluation and treatment plan. A voice disturbance that persists for more than 3 months, has no clear underlying etiology, or impairs a child's intelligibility, needs to be investigated. This chapter will discuss the clinical evaluation of children with voice disorders, describe several common laryngeal pathologies that affect children, and review treatment options including voice therapy, medical management, and surgical intervention.
Vocal folds grow in length and mature structurally from infancy through adolescence. These changes do not occur in a linear manner, and are accompanied by changes in a child's fundamental frequency as well as their vocal range and control. There is a period of more rapid growth from birth through 3 years of age, then slower growth, until another period of rapid growth during adolescence and puberty. Before puberty, the larynx is similar in size for boys and girls and there is not a great deal of voice difference based on gender.1 During puberty, the laryngeal and vocal fold growth rate is greater for boys with a corresponding greater change in fundamental frequency.2
The definition of what constitutes a “pediatric voice disorder” is not generally uniform, though may be understood as a perceptual deviation of at least one standard deviation from normal of the qualities of overall severity, roughness, breathiness, strain, pitch, or loudness. Voice disorders in children are felt to be fairly common, with a reported incidence ranging from 6 to 25% of children.3–5 The most common cause of hoarseness in children—vocal fold nodules—is more common in boys than girls by an almost 2:1 ratio in school-age children. However, in the teenage population, there is a strong female preponderance.6–8 There has been a surging interest in pediatric voice disorders over the past decade, partly due to the realization that there are therapeutic interventions which can have a positive impact on a child's voice quality and intelligibility, and partly due to technological advances in our diagnostic equipment.
A clinician's ability to judge a child's voice quality may be based on observations in the office setting during conversational speech as well as parental report as to whether such speech sample is typical for their child. Beyond an informal perceptual assessment, it is also helpful to use a validated scale that may describe a child's voice quality. The Consensus Auditory-Perceptual Evaluation of Voice scale has been developed and adopted by the American Speech-Language-Hearing Association Special Interest Division 3 (Voice and Voice Disorders) as the recommended standard protocol for the perceptual assessment of disordered voices.9 Perceptual qualities including overall severity, roughness, breathiness, strain, pitch, and loudness are rated on a visual analog scale (Appendix I).
Computer-based programs to analyze voice are widely available and are a useful adjunct in creating an objective description of audible characteristics of voice. These tools may be used in children as young as 4 years of age, and sometimes even in younger children. Routine acoustic measurements include fundamental frequency, intensity, frequency and intensity perturbations (jitter and shimmer), and signal-to-noise ratio. In singers, phonation range is also measured. Variations from normative values based on age and gender may reflect on the size, tension, irregularity, biomechanics, and state of hydration of the vocal folds.
Aerodynamic Measures and Electroglottography
Aerodynamic tests allow the clinician to measure air pressure, flow rate, and resistance during voice production. Subglottic and supraglottic air pressure as well as glottic impedance and volume flow rate are recorded while a child phonates into a facemask. An inefficient glottal valve, due to a nodule or polyp, may result in higher glottal airflow and the perceptual quality of breathiness. Electroglottography is a noninvasive means of measuring vocal fold vibratory behavior. Electrodes placed on opposite side of the neck overlying the larynx allow for measurement of variation in electrical resistance (impedance) through the larynx. This measure of vocal fold contact, however, does not examine noncontact vibratory events. Both these measures are still relatively new to the pediatric population, and their value will be determined over time.
The laryngeal examination is typically performed after perceptual and acoustic measures have been recorded, and allows for the consolidation of all clinical information and the confirmation of a diagnosis. There are several options for obtaining an excellent view of a child's larynx. In general, most preschool and school-age children, and young teens are best examined with a flexible nasolaryngoscope passed transnasally. Either a traditional fiberoptic nasolaryngoscope or one of the newer distal-chip flexible scopes may be used, with attention to the diameter of the scope chosen appropriate to the age of the child. A mixture of 4% lidocaine solution and 0.25% oxymetazoline solution is sprayed into one of the nasal passages. The scope may be advanced through the inferior meatus or middle meatus, depending on the child's individual anatomy. A complete laryngeal examination includes visualization of the supraglottic larynx, false and true vocal folds, arytenoids, and possibly also the subglottis. Gross vocal fold speed and range of movement are noted. The patient is asked to phonate “/eeee/” at various pitches, to assess for lesions that may only be apparent at higher frequencies when the vocal folds are elongated and thinned. The use of stroboscopy may be especially helpful in assessing epithelial and subepithelial lesions, scarring, and disruptions of the mucosal wave. Supraglottic compression may reflect underlying vocal hyperfunction or compensation for vocal fold immobility or scarring. A laryngeal examination summary sheet is helpful in reporting and documenting the noted abnormalities (Appendix II).
Rigid laryngeal telescopes have historically provided the most optically clear, bright, and undistorted images of the larynx. These telescopes are now available in diameters as small as 6 mm, and may be tolerated in some older school-age children as well as teenagers. The use of an intraoral topical anesthetic spray may help reduce gag sensation and improve cooperation.
Vocal Fold Pathology in Children
The underlying etiology of a child's voice disorder may be related to issues that may be missed if attention is directed only to the vocal folds themselves. The patency of a child's lower airway as well as his pulmonary status should be considered for any abnormalities that may affect breath support. The presence of tracheal stenosis, tracheomalacia, or subglottic stenosis may limit airflow through the larynx and impair voice production. Lower airway reactivity with associated exercise or cold-air–induced asthma may result in increased coughing and throat clearing as well as decreased subglottic air pressure. The presence of neck muscle tension may give an important clue for underlying laryngeal strain and vocal hyperfunction.
Glottic lesions are the most common cause of a child's voice disturbance. Vocal fold nodules and polyps are epithelial lesions located in the anterior membranous vocal fold. Large vocal fold nodules may affect glottal closure, and be accompanied both by breathiness as well vocal strain/hyperfunction (Fig. 17.1). Vocal fold nodule size may be graded by the examining clinician, based on a validated scale.10There is a significant relationship between vocal fold nodule size and overall severity of a child's voice disturbance.11 Subepithelial lesions, such as keratin or mucus-filled cysts, will affect vocal fold vibratory behavior, with resulting reduced range and amplitude of vocal fold mucosal wave as well as incomplete glottic closure (Fig. 17.2). These lesions may cause a reactive nodule on the contralateral vocal fold. Dilated and tortuous blood vessels, known as vocal fold varices, may hemorrhage within the vocal fold and result in areas of stiffness. The epithelial covering of the vocal fold may scar down to the underlying vocal ligament (sulcus vocalis)—a finding that may be congenital in nature or result from rupture of a subepithelial cyst. Iatrogenic injury to the vocal folds, as may occur from prior surgical removal of a lesion or from airway reconstructive surgery, may cause scarring of the vocal folds with loss of the normal vibratory characteristics of the mucosal wave (Fig. 17.3). Areas of scarred and adynamic mucosal wave may result in alterations of pitch, vocal breaks, diplophonia, loss of upper vocal range, and vocal fatigue.
Figure 17.1 Vocal fold nodules.
Figure 17.2 Vocal fold cyst.
Figure 17.3 Iatrogenic scarring of vocal folds.
Vocal fold immobility may be idiopathic or congenital in nature, may have a central nervous system or brainstem etiology, or may be due to recurrent laryngeal nerve injury. The underlying cause may be mass effect causing pressure or traction on the recurrent laryngeal nerve, or direct injury to the nerve during cardiothoracic surgical procedures. In addition, prolonged endotracheal tube intubation as well as laryngeal reconstructive surgery may result in cricoarytenoid joint fixation with reduced or absent arytenoid movement. A child with unilateral vocal fold immobility will have a resulting weak and breathy voice quality, which may be associated with increased strain and decreased loudness (Fig. 17.4). Bilateral vocal fold immobility may allow a child to phonate with a fairly strong clear voice, though with associated stridor and dyspnea with exertion.
Congenital lesions may underlie a child's long-standing voice disorder. An anterior glottic web may result in a strained, high-pitched vocal quality, and possibly may interfere with a child's airway with resulting stridor (Fig. 17.5).
Infectious causes of voice disorders include self-limited viral inflammation of the larynx and vocal folds, due to rhinoviruses, parainfluenza viruses, respiratory syncytial virus, and others. A diagnosis of acute laryngitis based on a viral etiology can be managed with conservative measures. Recurrent respiratory papillomatosis caused by human papilloma virus (HPV) may result in long-term laryngeal involvement requiring multiple procedures over a patient's lifetime (Fig. 17.6). Various surgical instruments and techniques have evolved to treat this condition, including cold steel laryngeal instruments, carbon dioxide lasers, laryngeal microdebrider, and additional lasers with varying wavelengths and tissue effects. The underlying surgical premise is to preserve the airway, avoid any damage to the superficial lamina propria of the vocal fold, while trying to minimize the number of procedures in a given child. Ultimately, however, the greatest promise may be in the vaccination of all children, both girls and boys, before they become sexually active. Current recommendations are that all boys and girls receive the quadrivalent HPV vaccine at age 11 to 12 years.12 With the expected decreased incidence of HPV in general, there will also be an expected decreased incidence of laryngeal papillomatosis.
Figure 17.4 Unilateral vocal fold palsy.
Figure 17.5 Anterior glottic web.
Functional voice disorders may be present in the pediatric patient with a structurally normal larynx. These are more common in the adolescent years, and may manifest in near total aphonia or a severe dysphonia. The term “muscle tension dysphonia” may be used to describe this condition, with increased tension within the intrinsic laryngeal muscles and resulting inefficient and ineffective vocal production. Boys may maintain a persistently high pitch voice or hoarseness at puberty and beyond, and not be able to transition to the expected lower pitch as their larynx grows. This is referred to as a mutational voice disorder or “puberphonia.” These functional voice disorders are best managed through voice therapy with an experienced speech–language pathologist.
Figure 17.6 Laryngeal papilloma.
Measurement of Impact
Quality-of-life scales may be useful to better understand the impact of a person's voice disorder on their lifestyle. The Voice Handicap Index (VHI) and the Voice-Related Quality of Life index are designed to address self-perception of emotional, physical, and functional impact in relation to voice.13,14 A quality-of-life scale oriented toward the pediatric patient is the Pediatric Voice-Related Quality of Life scale, intended for administration with the parent(s) of a child with a voice disorder.15
The ideal treatment plan for a child with a voice disorder is multifaceted. This includes education to the child and his/her parents, vocal hygiene, direct voice therapy, as well as medical and/or surgical intervention. Education requires explaining the diagnosis and nature of the voice problem in a manner appropriate to a child's age and cognitive level, with additional details provided to the parents. Visual images, review of stroboscopy recordings, and line drawings are all helpful. Improved comprehension by the patient and his/her parents will improve compliance as well as help them develop realistic expectations from treatment.
Vocal hygiene includes maintenance of good hydration, moderation of amount of voice use and volume of voice, dietary precautions to minimize laryngopharyngeal reflux, and reduction/elimination of vocal abuse. Basic vocal hygiene is reviewed with the entire family, with an emphasis on creating an atmosphere of positive reinforcement for achieving the targeted behavior. Behavioral approaches to voice hygiene are generally appropriate in the preschool and school-age group of children.
Direct voice therapy helps a child improve the manner of voice production and work toward achieving his/her best possible voice quality. Considerations involve breathing techniques to ensure proper breath support, reduction of increased neck and laryngeal muscle tension, coordination of respiration and phonation, and improvement in glottal closure. Various therapy techniques may be useful, depending on the age, developmental level, and motivation of the child.
Medical conditions associated with voice disorders should be recognized, appropriately evaluated, and treated in conjunction with management of the voice disorder. A diagnosis of pediatric laryngopharyngeal reflux (LPR) should be based on relevant history and symptoms, physical findings, and judicious use of testing. Findings during laryngoscopy may include posterior laryngeal mucosal hyperplasia, erythema, and pachydermia. Generalized vocal fold edema and erythema, thick mucus secretions, and lymphoid follicular hyperplasia (“cobblestoning”) of the hypopharyngeal mucosa are subjective observations that may reflect inflammation and irritation of the laryngeal mucosa from LPR. Objective measures of reflux include the use of pH probe studies, impedance manometry, and esophageal endoscopy and biopsy. Of note, the pediatric gastroenterologist evaluating for gastroesophageal reflux may have a different impression of the severity of findings as compared with the pediatric otolaryngologist evaluating for LPR.16–18 A child with a significant degree of dysphonia and notable laryngeal findings that are suggestive of LPR may warrant a trial of reflux management. This should be part of the overall management strategy, including patient and family education, improved hydration, vocal hygiene, dietary management of reflux, and direct vocal therapy. A 3-month trial of a proton pump inhibitor is reasonable, with follow-up assessment of the effects of the medication and the overall treatment plan. The strategy of prescribing a medication (proton pump inhibitor) without an overall treatment approach is not likely to be successful.
Asthma may be an important contributing factor in a child's voice disturbance. Coughing and throat clearing may traumatize the vocal folds with the subsequent development of vocal fold edema, nodules, polyps, and varices. Asthma medications, including the use of inhaled steroids and bronchodilators, may result in dehydration of the vocal folds and even some degree of vocal fold epithelial atrophy. Environmental allergies may cause vocal fold edema, increased upper airway secretions, coughing, throat clearing, and sneezing. Environmental controls at home are the first line of treatment. Antihistamines have a role as well; although they can lead to drying of the vocal folds and thicker secretions. Other medications, including nasal steroid sprays and leukotriene inhibitors, may be a part of allergy management. Sinusitis may contribute to voice disorders, due to upper aerodigestive tract inflammation, postnasal drip, and laryngeal irritation. Appropriate evaluation and treatment is an important part of improving the health of the larynx.
Surgery is rarely indicated as a first line of treatment for the majority of pediatric voice disorders. Patient and family education, vocal hygiene, improvement of state of hydration, management of associated medical conditions, and patience are the best approach in general. There are times, however, when surgical management is called for. Vocal fold nodules that significantly impact a child's voice quality and intelligibility and persist despite an appropriate period of therapy and monitoring may be considered for surgical excision. Risks include scarring of the vocal fold as well as recurrence of the nodules. Excellent microlaryngeal surgical techniques are required, and a 1-week period of voice rest after surgery is recommended. Vocal fold cysts may mimic vocal fold nodules but can be distinguished with the use of stroboscopy. These lesions are not likely to resolve spontaneously, and may be excised with microlaryngeal surgical techniques. The goal in this instance is to avoid complications related to chronic dysphonia with compensatory hyperfunction as well as risk of cyst rupture and scarring of the vocal fold epithelium.
Unilateral vocal fold palsy is associated with a weak, breathy, and strained voice quality. Neonates and infants with this condition may also exhibit dysphagia, with a higher risk of aspiration of thin liquids. Though a period of “watchful waiting” may allow some children to compensate and achieve a safe swallow, it is appropriate even in infants and young children to consider an injection medialization of the paralyzed vocal fold. This may be accomplished safely without airway compromise, and allow for an improvement in glottal closure and airway protection. Helping a child achieve a more “normal” voice quality at this younger age might be beneficial, during which time a higher degree of neural plasticity allows for better long-term voice results.
The school-age child with newly diagnosed vocal fold immobility may make some gains in voice quality with vocal therapy. Treatment goals include decreasing breathiness, improving loudness, and improving intelligibility. If treatment goals are not met with therapy alone, there may then be consideration of a medialization procedure. Injection medialization is an appropriate technique for younger children, whereas older school-age children and adolescents may be treated more effectively with laryngeal framework surgery.
When considering injection medialization, the surgeon may choose from several options that have different periods of effectiveness. Short-lived materials include Gelfoam (Pfizer, New York, United States) and Radiesse Voice Gel (BioForm Medical, San Mateo, California, United States), which may last for a few months before they are resorbed. Longer lasting materials include abdominal fat prepared appropriately for injection or commercially available substances made of a hydroxyapatite/water-based gel that may last for several years. Laryngeal framework surgery, including vocal fold medialization, has become an accepted technique for use in older children. There are commercially available vocal fold medialization implant systems. Of these, the Montgomery Thyroplasty Implant System (Boston Medical Products, Westborough, Massachusetts, United States) offers various sizes of male and female implants, with the ability to upsize the implants as a child's larynx grows.
Additionally, the use of nerve transfers from the ansa cervicalis nerve to the affected recurrent laryngeal nerve may help improve vocal fold tone with associated improvement in adduction and voice quality. This technique may be performed in conjunction with a vocal fold medialization procedure.
Vocal fold scarring is a difficult surgical problem to resolve. The superficial lamina propria is the layer of loose connective tissue beneath the vocal fold epithelium, and is necessary to achieve the desired vocal fold vibratory characteristics. This layer does not regenerate if damaged, and loss of the superficial lamina propria results in scarring and an adynamic area of the vocal fold. This is an area of active research, including the development of synthetic materials that may be injected into the vocal fold to re-create the characteristics of this important structure and hence to improve vocal fold mucosal wave and voice quality.
Pediatric voice disorders are common, and should be evaluated and treated in the context of the severity of the problem as well the impact on the child's life. A “total body” approach encourages the clinician to consider the child, his/her family, as well as home and school environmental influences in the causes and management of a child's voice disorder. Dysphonia in children may be a congenital problem, acquired though overuse and hyperfunction, or due to an infectious/inflammatory condition. Iatrogenic injury from prolonged intubation, laryngeal surgery, or cardiothoracic surgery are possible causes of a child's voice disturbance. Neoplasms causing hoarseness need to be diagnosed and treated appropriately. Related medical conditions may cause poor breath support, airway insufficiency, or chronic irritation of the larynx and vocal folds.
A coordinated team diagnostic approach, considering the entire child, the impact of any concurrent medical conditions, and the status of the larynx and vocal folds, will allow the voice clinicians to develop an age and developmentally appropriate treatment plan. There may be roles for simple monitoring, vocal therapy, medical management, and surgical interventions. It is the role of the voice care team to make an accurate diagnosis and also to individualize the treatment plan best suited for the child with a voice disorder.
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Appendix I Consensus Auditory-Perceptual Evaluation of Voice scale.
Source: Reprinted with permission from Consensus Auditory-Perceptual Evaluation of Voice: Development of a Standardized Clinical Protocol by G. B. Kempster, B. R. Gerratt, K. V. Abbott, J. Barkemeier-Kraemer, and R. E. Hillman. American Journal of Speech-Language Pathology, 18, 124–132. Copyright 2009 by American Speech-Language-Hearing Association. All rights reserved.
Appendix II Laryngeal examination record.