Alison J. Kemph and Devin L. McCaslin
Widespread initiatives for early identification of permanent hearing loss in infants have brought an increased focus to the early auditory development of children. It is now well established that hearing loss can delay a child's receptive and expressive speech and language, reduce academic achievement, and have significant social consequences. The Joint Committee on Infant Hearing (JCIH) endorses early hearing detection intervention (EHDI) for infants with hearing loss. The goal of EHDI is to maximize speech, language, and literacy development because children with hearing loss are known to be at risk for communication, cognition, reading, and social–emotional delays. One specific goal of EHDI is to ensure that children with hearing loss receive access to early intervention services before 6 months of age. However, no such guidelines or recommendations exist for children with vestibular impairments. In fact, until recently, very little attention has been directed toward understanding the consequences of vestibular impairments in children and what, if any, intervention should be prescribed.
This lack of guidelines is not due to a failure to understand how the balance system matures. The vestibular and visual systems are well developed at birth. It has been suggested that the reason for the early development is because these sensory systems are critical components in facilitating a child's ability to explore his or her environment. In fact, one of the key elements of the development of postural control and locomotion is a child's motivation to interact with his or her surroundings. When a developing child sees something of interest (e.g., a puppy), he or she will work to move toward the object of interest and attempt to interact with it. As infants begin to crawl toward and reach for objects, they must be able to see the objects clearly—even when the head is moving. The fovea of the eye has a high concentration of photoreceptor cells, known as cones, and is the part of the eye that has the highest spatial sensitivity. If the child wishes to visually examine an object in detail, the two foveae must be directed toward the target. When a child with a typically functioning vestibular system moves his or her head, the eyes are reflexively deviated in the opposite direction so that the image may be stabilized on the retina without blurring. This reflexive eye movement in response to the head movement is generated by the vestibular and ocular motor systems and is called the vestibulo-ocular reflex (VOR). Adults with peripheral vestibular impairment often describe a blurring of the visual field during head movements and are known to restrict the speed at which they turn their heads. Similarly, impairment in the peripheral vestibular system at birth can degrade a child's visual acuity during activity. That is, a child with vestibular hypofunction may have a deficient VOR, and that may alter his or her ability see clearly when the head is moving. It would then stand to reason that children with vestibular impairments may be slower than children with typical development in reaching key milestones.
It is well documented that children can have both vestibular impairments and hearing impairments simultaneously. Because of the close proximity of the auditory structures to the balance structures in the inner ear, impairment in one system increases the likelihood of impairment in the other. In fact, published reports have shown that vestibular dysfunction can occur in up to 85% of children with sensorineural hearing loss (Cushing, Papsin, Rutka, James, & Gordon, 2008; O'Reilly et al., 2011). Studies such as these have led to a renewed interest in the effects that impairments in the vestibular system have on the everyday functions of children. One of the distinct challenges facing health care professionals in the area of balance disorders is how to accurately identify vestibular disorders in young children and determine those who may benefit from intervention. When identifying hearing impairments, highly sensitive and specific technologies such as the auditory brainstem response (ABR) and otoacoustic emissions (OAEs) have made diagnosing hearing loss at an early age extremely effective. However, systems for diagnosing vestibular impairment with the performance characteristics of the ABR and OAE are still in development. In many cases, vestibular disorders are more difficult to identify in children than in adults. This is due, in large part, to the fact that a young child will rarely complain of dizziness in the same way that an older child or adult will. A child born with a vestibular impairment has no reference for what "normal" is and so may be unaware that anything is wrong. Furthermore, a child experiencing vertigo may lack the necessary language skills to verbalize the abnormal sensations that he or she is experiencing. Recognizing a child with a vestibular deficit requires coordinating descriptions of the problem offered by the caregiver and child with the clinical observations made by additional health care professionals (e.g., pediatrician or neurologist). This poses an additional challenge because vestibular disorders in young children may be dismissed by professionals and caregivers alike (Tusa, Saada, & Niparko, 1994), and the symptoms may be mischaracterized as simply "behavioral problems" (e.g., finding ways to attract attention) or being "clumsy." It is important for professionals to recognize when signs of vestibular disorders do exist—studies have shed light on the extent to which these impairments affect the daily lives of children. Not only do children with vestibular deficits report being dizzy or having visual acuity problems with head movements, but they have also been shown to have significantly more difficultly reading as well as to have severe motion intolerance, impaired gait, and delays in motor milestones.
Clinicians who interact with children on a daily basis should understand the causes and prevalence of balance problems in the pediatric population. In this way, those children at risk can be identified and provided with timely intervention. Because vestibular impairment is the single most commonly associated feature of sensorineural hearing loss, health care providers should always consider balance function and motor development in children with hearing loss. Specifically, children with etiologies such as meningitis, cytomegalovirus, ototoxicity, and auditory neuropathy spectrum disorder, and those with abnormal cochleovestibular anatomy should be considered for balance testing because the incidence of vestibular impairment is higher in these populations. For example, a recent report (Cushing, Gordon, Rutka, James, & Papsin, 2013) found that every child in a cohort of pediatric patients with hearing loss caused by meningitis also had an abnormal VOR, and nine out of 10 had a severe impairment in which no vestibular response could be elicited from either ear during caloric testing. There are also various syndromes and conditions associated with both hearing loss and vestibular impairment (e.g., Pendred, Waardenburg, Albers-Schonberg, Albinism, Ushers, Wolfram, and Alport) that may warrant formal vestibular assessment. For many patients, however, the cause of hearing loss may never be identified. Audiologists and speech-language pathologists who provide routine care to these patients may have a unique vantage point from which to monitor other factors that provide an indication of vestibular function, such as timeliness of gross motor milestones or the child's ability to perform more complex activities such as riding a bike, climbing a jungle gym, or learning to skateboard. Some pediatric audiology programs have even instituted clinical protocols to monitor motor milestones closely in their patients with hearing loss in order to determine whether further investigation into the status of the child's vestibular system is indicated.
Vestibular function studies should also be strongly considered in cochlear implant candidates. The prevalence of vestibular impairment is higher in children with severe to profound hearing loss, and research has shown that cochlear implantation itself may result in changes to vestibular function following surgery. Perhaps more important, emerging research shows that children with bilateral vestibular loss via caloric testing were 8 times more likely to have a mechanical or electrical failure of their cochlear implant (Wolter, Gordon, Papsin, & Cushing, 2015). The implication is that children with impaired balance are more likely to incur falls, with head injuries causing damage to the internal components of the implant. The potential consequences of this finding are significant not only to communication—the child may experience significant difficulty communicating without use of the implant—but also to the cost and health implications of reimplantation surgery. Identifying children who are at high risk for cochlear implant failure would allow for additional counseling, as well as early therapeutic intervention, prior to implantation.
Last, children may have vestibular impairment without any associated hearing loss. Most often, these children have vestibular symptoms associated with migraine or migraine variants (which account for approximately 30% of cases of childhood dizziness and vertigo), concussion/head trauma, viral infection, or recurrent otitis media. Older children may be able to describe dizziness or imbalance, but younger children may be limited by vocabulary or developmental ability to express their symptoms. Instead, young children may exhibit acute signs of dizziness such as pallor, unexplained fright, or unsteadiness. Although vestibular deficits in children have been largely unrecognized until lately, a prevalence study found that 1% of children ages 0–18 years presenting to a pediatric health system over a 4-year period had a primary complaint related to balance (O'Reilly et al., 2010). Of those, 0.45% received a diagnosis of a balance disorder. One challenge for health care providers is determining which patients would ultimately benefit from specialized vestibular testing.
One approach that has been used successfully in adults to help identify individuals with significant dizziness is to measure the impact of dizziness on the individual's psychosocial function (i.e., handicap). It is now standard practice to assess handicap in adults for a number of modalities (e.g., hearing and tinnitus). Self-report measures have become popular because they measure disability and/or handicap from the patient's perspective, which has been shown to be, in most cases, disparate compared with impairment measured with semi-objective measures (e.g., vestibular evoked myogenic potentials). A similar strategy may be effective in the pediatric population. In an effort to develop a device to identify children with significant handicap due to dizziness, we developed an assessment tool for use in pediatrics. The device is called the Pediatric Dizziness Handicap Inventory for Caregivers (pDHI-PC; McCaslin, Jacobson, Lambert, English, & Kemph, 2015). The scale is designed for use with children 5–12 years of age (see attached PDF). Development of this instrument consisted of three phases designed to provide caregivers with a reliable method to report and quantify the impact of dizziness on their child's everyday life. The pDHI-PC is composed of questions that are written in such a way that they can be answered by the child's caregiver using a simple "yes," "sometimes," or "no" response. The subject matter of the questions is focused on the physical, emotional, and functional aspects of life that can be affected by a balance problem. Formal investigation using the pDHI-PC yielded interquartile scores that can allow the clinician to quantify a child's activity limitation as "none," "mild," "moderate," or "severe." The pDHI-PC is a psychometrically robust tool that is reliable, easy to administer, and easy to score. Not only does it have the potential to provide clinicians with information regarding a child's handicap imposed by dizziness, but it may prove to be useful in assessing the efficacy of therapeutic intervention.
Once a child has been identified with significant balance impairment, it is important to have resources available for intervention. First, a medical referral—usually to an otolaryngologist—is typically recommended. Other referrals may be indicated as well. For example, if migraine-associated vertigo is suspected, a referral to a neurologist and/or an ophthalmologist may be advised. Once it is determined that a child has a peripheral vestibular impairment, he or she may be referred for vestibular rehabilitative therapy (VRT) with a specially trained physical or occupational therapist. The goals of VRT can vary depending on the type and extent of vestibular deficiency. Typically, therapy involves the use of three main strategies for rehabilitation: habituation, adaptation, and substitution. Habituation exercises are targeted for children with vestibular symptoms and focus on minimizing symptoms by repetitive exposure to provoking movements. Adaptation activities typically concentrate on modifying the VOR by asking the patient to keep his or her focus on a visual target during specific head movements. The goal of these activities is to work on improving the child's coordination of eye and head movements. Substitution strategies involve use of visual or somatosensory systems, rather than the impaired peripheral vestibular system, to maintain balance. Research has shown vestibular rehabilitation to be successful in improving gross motor skills, postural control, dynamic visual acuity, and even reading acuity in pediatric patients with vestibular deficits. Functionally, these improvements can assist children with important day-to-day activities such as note-taking in the classroom—which requires quick movements of the head up to look at the chalkboard and down to focus on the paper.
In conclusion, although EHDI has been on the forefront of health initiatives for the past 20 years, awareness of vestibular impairment in children has only recently begun to grow. Mounting research shows that vestibular impairment significantly affects multiple aspects of the life of the developing child. Strategies used in vestibular rehabilitation promote significant, meaningful improvements in the functional activities of pediatric patients with vestibular impairment. For this reason, it is the responsibility of health care providers to be mindful of balance and dizziness problems in pediatric patients. Specifically, audiologists and speech-language pathologists must remain vigilant for signs of this disorder in their patients, considering the fact that many of their pediatric patients may be at higher risk for impairment than individuals in the general population.
Alison J. Kemph is a pediatric audiologist and newborn hearing screening coordinator at the Vanderbilt Bill Wilkerson Center in Nashville, Tennessee. Alison joined the Vanderbilt Bill Wilkerson Center team in 2012 after receiving her AuD from Vanderbilt University School of Medicine. She is responsible for managing more than 4,400 newborn hearing screenings in the newborn nursery and Level IV neonatal intensive care unit (NICU) annually. Alison also works in advanced diagnostic settings, completing unsedated and sedated ABRs as well as behavioral testing in the pediatric population. Alison's interests include EHDI, electrophysiology, pediatric vestibular assessment, and clinical research. Contact her at firstname.lastname@example.org.
Devin L. McCaslin is an associate professor at the Vanderbilt Bill Wilkerson Center in Nashville, Tennessee. He received a master's degree in audiology from Wayne State University and a PhD in hearing science from The Ohio State University. Following the completion of his PhD, McCaslin took a position as a clinical audiologist at the Dayton Veteran's Administration Hospital for 2 years and then joined the Division of Audiology at Henry Ford Hospital in Detroit. McCaslin joined the faculty at the Bill Wilkerson Center in the Vanderbilt School of Medicine in 2004. At the Center, he is the associate director of audiology and co-director of the Division of Vestibular Sciences. McCaslin maintains a clinical practice and is an instructor in both the AuD and PhD programs. His major academic, clinical, and research interests relate to clinical electrophysiology, tinnitus, and vestibular assessment. Contact him at email@example.com.
Cushing, S. L., Papsin, B. C., Rutka, J. A., James, A. L., & Gordon, K. A. (2008). Evidence of vestibular and balance dysfunction in children with profound sensorineural hearing loss using cochlear implants. Laryngoscope, 118(10), 1814–1823.
Cushing, S. L., Gordon, K. A., Rutka, J. A., James, A. L., & Papsin, B. C. (2013). Vestibular end-organ dysfunction in children with sensorineural hearing loss and cochlear implants: An expanded cohort and etiologic assessment. Otology & Neurotology, 34, 422–428.
McCaslin, D. L., Jacobson, G. P., Lambert, W., English, L. N., & Kemph, A. J. (2015). The development of the Vanderbilt Pediatric Dizziness Handicap Inventory for Patient Caregivers (DHI-PC). International Journal of Pediatric Otorhinolaryngology, 79, 1662–1666.
O'Reilly, R. C., Morlet, T., Nicholas, B. D., Josephson, G., Horlbeck, D., Lundy, L., & Mercado, A. (2010). Prevalence of vestibular and balance disorders in children. Otology & Neurotology, 31, 1441–1444.
O'Reilly, R. C., Greywoode, J., Morlet, T., Miller, F., Henley, J., Church, C., Campbell, J., ... Falcheck, S. (2011). Comprehensive vestibular and balance testing in the dizzy pediatric population. Otolaryngology–Head & Neck Surgery, 144, 142–148.
Tusa, R. J., Saada A. A., Jr., & Niparko, J. K. (1994). Dizziness in childhood. Journal of Child Neurology, 9, 261–274.
Wolter, N. E., Gordon, K. A., Papsin, B. C., & Cushing, S. L. (2015). Vestibular and balance impairment contributes to cochlear implant failure in children. Otology & Neurotology, 36, 1029–1034.
See the Vanderbilt Pediatric Dizziness Handicap Inventory (DHI) [PDF].