This article reviews the management of voice disorders in children. We describe the relevant anatomy and development of the larynx throughout childhood, which affects voice. We consider the epidemiologic data to establish the size of the problem. The assessment of the patient in the clinic is described stepwise through the history, examination, laryngoscopy, and extra tests. We then review the common voice disorders encountered and their management, concluding with discussion of future directions, which may herald advances in this field.
Key points
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Understanding the distinct anatomy of the pediatric larynx and changes that occur through to adolescence is key to effectively managing voice disorders in children.
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Multidisciplinary pediatric voice clinics are increasing, and provide an excellent setting for detailed assessment in an office environment.
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Awake laryngoscopic examination in the office is possible in most children and provides superior dynamic information compared with a rigid laryngoscopy under anesthetic.
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It is important to distinguish those conditions that may recover spontaneously, those that respond to speech and language therapy, and those that require surgical intervention to allow appropriate patient and parent counseling.
Introduction
There have been great advances in knowledge regarding voice disorders and strategies for managing them in recent years. This initially occurred in adult practice, with the development of the subspecialty of phoniatrics, which has evolved rapidly. It is now common for ear, nose, and throat (ENT) departments to have a clinician with a specialist interest in phoniatrics and a multidisciplinary voice clinic. This experience has more recently been applied in the pediatric setting to guide assessment and management of voice disorders in children.
Introduction
There have been great advances in knowledge regarding voice disorders and strategies for managing them in recent years. This initially occurred in adult practice, with the development of the subspecialty of phoniatrics, which has evolved rapidly. It is now common for ear, nose, and throat (ENT) departments to have a clinician with a specialist interest in phoniatrics and a multidisciplinary voice clinic. This experience has more recently been applied in the pediatric setting to guide assessment and management of voice disorders in children.
The pediatric larynx is different
To effectively manage childhood voice disorders, it is important to consider the differences between the child and adult larynx and indeed the transition between the 2 during adolescence. In a child, the larynx is relatively smaller, and sits in a higher position, with the cricoid at the level of the fourth cervical vertebra compared with the sixth in an adult, which can have an impact on endoscopic access. The epiglottis has a more tightly curled shape. The vocal folds are shorter with a reduced membranous–to–cartilaginous fold ratio. The structure of the vocal fold is immature, lacking the 5 layers seen in the adult vocal fold. The mucosa of the subglottis is more reactive and therefore prone to edema, hence the predisposition to croup and laryngeal obstruction in children. The suggestion that the subglottis is the narrowest level of the pediatric airway has been challenged, with the finding that in children the narrowest part is also at the glottic level, with no evidence of the classically described funnel-shaped larynx; however, this observation has been made in anesthetized paralyzed children ( Table 1 ).
| Features | Pediatric | Adult |
|---|---|---|
| Position | Higher (cricoid T4) | Lower (cricoid T6) |
| Shape | Curled epiglottis | More open epiglottis |
| Vocal fold structure | Immature | Mature: 5 layers |
| Vocal cords | Membranous:Cartilage ratio 1.0:1.5 | Membranous:Cartilage ratio 1.0:5.0 |
| Mucosa | Reactive, prone to edema | Less reactive |
Epidemiology
Epidemiologic data suggest that the prevalence of voice disorders in children is high, with figures in the 1960s to 1980s reported between 6% and 23% in 5-year-olds to 18-year-olds. In most of these cases, the voice problem is not perceived to be a concern by the parents or children, and they therefore do not seek medical attention. They have often become accustomed to a slightly abnormal pitch or tone, and the suggestion that this may represent an abnormality often comes from an external individual (eg, a teacher when a child starts school), which may trigger a medical review. The range of voice problems that do present varies widely, from those child performers with normal conversational voice but concern about loss in the upper range of their singing voice, to those with severe laryngeal pathology and no voice at all. After a thorough assessment, the appropriate voice therapy, and, on occasion, surgical treatment, most voice disorders in children can be improved.
There is evidence in the literature to demonstrate the impact of voice disorders in children, both in terms of the child’s perception of themselves and how they are perceived by others. A study carried out in the United States in 2008 used the pediatric voice-related quality-of-life instrument in 95 children with vocal nodules, vocal fold paralysis, and paradoxic vocal fold dysfunction. The study found reduced total scores, and reduced scores in social-emotional and physical-functional domains compared with children without voice dysfunction. A separate study assessed the attitudes of adults in response to listening to children with dysphonia, finding significant negative perceptions of the children as “dirty, weak, sick, ugly” compared with their peers without dysphonia.
Development of the larynx
It is beyond the scope of this review to discuss the embryology of the larynx, which is well described elsewhere, although it is important to bear in mind that some causes of voice disorders may be congenital and relate to the embryologic development of the larynx. An example is a glottic web, resulting from incomplete recanalization of the embryonic larynx at approximately 10 weeks’ gestation. The postnatal changes that occur during the growth and development of the larynx are also pertinent to development and management of voice disorders and therefore a description of those is included. The work of Hirano and colleagues during the 1980s informs much of this knowledge.
Vocal Fold Growth
The length of the vocal folds is equal in both genders (6–8 mm) until the age of 10 years. Following this, there is significant growth in both boys and girls; however, more marked in boys, with the membranous vocal fold increasing to 14.8 to 18.0 mm, compared with 8.5 to 12.0 mm in girls. The cartilaginous part of the vocal cord also lengthens with age, but relatively less, so that the ratio of membranous-to-cartilaginous fold is 1.5:1.0 in the newborn, 4.0:1.0 in the adult female, and 5.5:1.0 in the adult male. Hirano and colleagues also derived the concept that the posterior wider glottis acts as the respiratory glottis, with the phonatory glottis anteriorly. This is an important consideration when planning phonosurgery, such as arytenoidectomy in bilateral cord palsy. Increasing the airway size exclusively posteriorly should have a limited impact on the voice outcome.
Vocal Fold Structure
The understanding of the layered vocal fold structure is key to phonosurgery in adults. The 5 layers are the epithelium; the superficial, intermediate, and deep layers of the lamina propria; and the muscle layer. The 2 most superficial layers are known as “the cover,” moving freely over the deeper layers. These form the vocal ligament and body of the vocal fold, and care should be taken to maintain these intact to preserve voice. Hirano and colleagues and others have observed that this structure is not present at birth, but rather starts to develop during the first months of life, reaching recognizable adult structure by puberty. This provides a challenge in phonosurgery in young children, as the lack of a clear plane of dissection in the superficial lamina propria makes raising microflaps more difficult.
The pitch of the voice in children is a characteristic difference from the adult voice. Pitch lowers gradually throughout infancy and childhood in both genders, with a more marked change at puberty, most significant in boys. This pitch change relates to the anterior growth of the thyroid cartilage, driven by testosterone, and corresponds to the external development of the thyroid prominence or Adam’s apple.
Assessment
Children with voice disorders may be seen in a general or specialist voice clinic. The history and basic ENT examination are the same in both settings; however, the specialist clinic provides the added benefit of the combined expertise of an otolaryngologist and speech and language therapist. There should also be the availability of videostroboscopic equipment and expertise to use it for a more detailed assessment. The availability of this clinic is likely to vary and, therefore, whether all children are seen in such a clinic or whether screened initially in a general clinic will differ between departments. The general trend is toward children with dysphonia being seen in specialist pediatric voice clinics.
History
A key step early on when taking the history is to distinguish whether the child has a voice disorder rather than a problem with speech, articulation, or language. The presenting symptom in voice disorders is, classically, hoarseness, whereas mispronunciation suggests a problem with speech and articulation, and inability to find the correct words relates to a disorder of language ( Table 2 ).
| Symptom | Classification of Problem |
|---|---|
| Hoarseness | Disorder of voice |
| Mispronunciation | Disorder of speech/articulation |
| Problems with word finding | Disorder of language |
Where possible, information should be sought from both the parents and the child. The chronology of the symptom is helpful. If the problem has been present since birth, a congenital pathology is likely, although a history of intubation in the perinatal period may be more suggestive of an acquired pathology, such as subglottic stenosis, formation of cysts, or cricoarytenoid fibrosis. It is common for later-onset symptoms to be related to an upper respiratory tract infection with associated laryngitis, with persistence of the hoarseness exacerbated by voice misuse. The severity of the problem ranges from a complete loss of voice to loss of singing voice in certain situations. The perceived importance of the disorder is also variable, with very mild dysphonia a serious concern to children who perform, or aspire to. The time course of the dysphonia is also important, an intermittent dysphonia is less likely to indicate a discrete vocal cord lesion, although the symptom may fluctuate and fatigue throughout the day.
The presence of associated laryngeal symptoms is an indicator of possible serious underlying pathology and must not be missed. Stridor and reduced exercise tolerance suggest an obstructive pathology, such as laryngeal stenosis or papillomas. Swallowing problems or choking may suggest vocal fold paralysis.
Other pathologies may influence the health of the larynx. It is helpful to inquire about symptoms suggestive of laryngopharyngeal reflux, which may cause local irritation and dysphonia. Throat clearing related to postnasal drip in allergic rhinitis will do the same. Respiratory disease may also cause dysphonia via several mechanisms. Persistent cough can lead to hoarseness, restrictive pathology reduces infraglottic pressure affecting the strength of the voice, and corticosteroid inhalers used to treat asthma can also cause dysphonia, which may be amenable to modification of the regimen or inhaler technique.
Less direct symptoms may also have an impact; for example, hearing loss may encourage the child to shout, leading to voice misuse–related dysphonia. It is helpful to ask about voice use in general and in the home environment. It has been noted that children with larger sibling groups have a higher prevalence of dysphonia associated with voice misuse. This can be related to development of vocal nodules. Asking about smoking and alcohol use may also be relevant.
Examination
A general otolaryngologic examination should be performed, including examination of the ears and hearing. Assessment of the voice should be thorough and may use a combination of subjective and objective voice analysis measures, including perceptual evaluation of voice, videostroboscopic imaging of vocal cord movement, and acoustic analysis. Self-assessment tools are also valuable. In the authors’ practice, children and their parents attending voice clinic are asked to complete the voice handicap index and a vocal tract discomfort scale, which was modified from a study in adults with muscle tension dysphonia by Mathieson and colleagues in 2009. These are repeated following voice therapy or surgical intervention to aid assessment of the outcome of these interventions.
The aims of examining the larynx can be considered as twofold. First, to assess for any evidence of a structural abnormality, such as a cyst, nodule, or papillomata. Second, to assess the dynamic view of laryngeal function during phonation to identify problems, such as vocal cord paralysis or muscular hyperfunction. There are several methods of laryngoscopic examination, each of which has advantages and disadvantages ( Table 3 ).
| Modality | Advantages | Disadvantages |
|---|---|---|
| Microlaryngoscopy (general anaesthetic [GA]) | Full cooperation Ability to biopsy/excise | Invasive Limited dynamic view |
| Flexible nasendoscopy | Well tolerated Awake Good view | Limited time Limited stroboscopy |
| Awake rigid endoscopy | Awake Best dynamic view Teaching aid | Less well tolerated |
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