Cisplatin Ototoxicity in Children: Implications for Primary Care Providers

Jessica Helt-Cameron, MSN, MA, RN; Patricia Jackson Allen, MS, RN, PNP, FAAN

Disclosures

Pediatr Nurs. 2009;35(2):121-127. 

In This Article

Implications for Primary Care

Importance of Hearing in Children’s Development

Children’s ability to hear facilitates many domains of their development, including their cognitive development. In young children, hearing and auditory processing play key roles in language acquisition (including vocabulary, phoneme, morpheme, syntax, and grammar development), and the development of literacy and reading skills. Undetected or uncorrected hearing loss in early childhood can interfere with children’s normal speech and language development (Kiese-Himmel, 2008; Moeller, Tomblin, Yoshinaga-Itano, Connor, & Jerger, 2007). Children who acquire hearing losses after the language acquisition years can be affected in slightly different ways. They can have trouble attending to or cognitively processing information at school, which can lead to academic difficulties. In a study of childhood neuroblastoma survivors, Gurney and colleagues (2007) found that children with hearing impairments secondary to their cancer treatments were more than twice as likely to have difficulties with reading, math, or attention skills than children who did not acquire any hearing losses from treatment.

Children’s social development can also be affected by hearing losses. Young children learn to read other’s social cues as they develop peer interaction and communication skills. Social cues and communication with others can be done in both verbal and non-verbal ways. If children are unable to hear or process these verbal cues, they do not attend to them and may respond inappropriately to their peers (Brinton & Fujiki, 2002; Brown, Bortoli, Remine, & Othman, 2008). This puts children with undetected hearing impairments at risk for developing social difficulties with peer relations, which can negatively influence their socio-emotional development. For a detailed description of the impact of hearing impairments on children’s social development, see Brinton and Fujiki, 2002.

Monitoring Hearing in Primary Care

When to monitor hearing. Since children’s ability to hear is crucial to their cognitive, social, and language development, universal guidelines for hearing screening have been established. As part of the Recommendations for Preventive Pediatric Health Care, Bright Futures and the American Academy of Pediatrics (2008) recommend formal hearing screening in newborns and all children of ages of 4, 5, 6, 8, and 10 years. At all other ages and preventive health care visits, they advocate for the clinician to conduct hearing risk assessments, and if appropriate, follow up by performing a hearing screen measure, such as otoacoustic emissions testing or pure tone audiometry.

Since childhood cancer survivors treated with cisplatin are at increased risk for developing hearing impairments, primary care clinicians need to monitor their hearing more closely. Typically, children’s hearing will be monitored by their oncology team during their chemotherapy treatment. Once children complete treatment, they may seek follow-up care in their regional cancer survivorship clinics or from their primary care doctor. Children followed in late effects clinics may have their hearing tested there; those not followed in late effects clinics must be regularly screened in primary care. The Children’s Oncology Group’s (2006) long-term follow-up guidelines for cancer survivors recommend yearly clinical histories of any hearing difficulties, otoscopic examinations of outer and middle ear structures, and sensorineural hearing screening for children who received cisplatin chemotherapy. If any hearing loss is detected or if results of the screening tests are inconclusive, children need to be referred directly to an audiologist who is familiar with the late effects of childhood cancer chemotherapy. Since cisplatin hearing loss is progressive, the audiologist determines how often children with hearing loss must be re-tested based on their total cumulative dose of cisplatin and their age when it was administered.

How to monitor hearing. The Children’s Oncology Group recommends using otoacoustic emissions, pure tone audiograms, or auditory-evoked response tests to monitor for cisplatin-induced sensorineural hearing loss in cancer survivors. However, in studies of childhood cancer survivors, distortion-product otoacoustic emissions (DPOAE) testing was found to be a more sensitive screening tool for hearing losses than pure tone audiometry and transient-evoked otoacoustic emissions testing (Dhooge et al., 2006; Knight, Kraemer, Winter, & Neuwelt, 2007; Stavroulaki, Apostolopoulos, Segas, Tsakanikos, & Adamopoulos, 2001). These studies advocate for DPOAE testing to become the preferred method to monitor inner ear cochlear function and detect sensorineural hearing losses related to cisplatin ototoxicity.

DPOAE testing is a non-invasive test where a small probe is inserted into the outer ear canal of the child. The probe itself is connected to a small portable computer device. The otoacoustic emissions device is programmed to emit acoustic sounds at variable frequencies and digitally measure the response of the hair cells in the cochlea to those sounds. DPOAE testing differs from other forms of otoacoustic emissions screening because it measures the hair cell’s response to two sounds of different frequencies emitted simultaneously (Stavroulaki et al., 2001; Wagner, Heppelmann, Vonthein, & Zenner, 2008). After conducting the test, the computer device digitally analyzes the cochlear response and determines whether the child’s hearing requires further assessment. Usually, the DPOAE device summarizes its findings into “pass” or “refer” results. Complex DPOAE devices that communicate to office computer networks are available, and these devices enable the provider to print out the digital analysis or electronically transfer the test results into children’s medical records. While the cost of the portable DPOAE computer device can range from $4,000 to $25,000 depending on its degree of technological sophistication, the cost of the disposable probe covers needed for each patient is only about $0.50 to $1.00 per child (National Center for Hearing Assessment and Management, 2008).

The DPOAE test offers many advantages to other traditional forms of hearing assessment, such as pure tone audiometry. First, it is a sensitive screening tool with high test-retest reliability (Wagner et al., 2008). Test sensitivity of the DPOAE is superior to pure tone audiometry; it is able to detect drug-induced sensorineural hearing losses before pure tone audiometry measures can (Lonsbury-Martin & Martin, 2003; Stavroulaki et al, 2002). Second, DPOAE testing can be used with children of all ages, from newborns to adolescents, for regular assessment of their hearing in primary care settings. Third, it is a fast, efficient computerized method to screen children’s hearing. Although the test must be done separately for each ear, it takes less than 1 minute to perform on each child, taking approximately 15 to 30 seconds per ear (Stowe, 2009). Fourth, unlike pure tone audiograms that depend on the child’s cooperation to indicate when he or she hears a sound, DPOAE testing does not depend on children’s verbal or physical responses (for example, saying yes or raising their hand to indicate they heard a sound). The only requirement is that children stay relatively still for the few seconds the probe is in each ear. Fifth, medical assistants and/or nursing staff can be trained to use the device and administer the testing. They can incorporate it into their normal routine with children. Typically, a practice will only need one DPOAE device. Since the DPOAE device is portable, the medical and/or nursing staff can do the testing in the quiet environment of an examination room. Finally, computerized testing will also provide analysis and guidelines for when to refer children to an audiologist for further hearing assessment. Although other forms of hearing screening are available, DPOAE testing provides many benefits and is practical for primary care settings. The major disadvantage to DPOAE testing is the cost of the equipment; it is markedly more expensive than pure tone audiometers, which range in price from $500 to $1500 (American Speech-Language Hearing Association [ASHA], 2009c).

Family Education

Primary care clinicians have a responsibility to educate childhood cancer survivors and their families about the necessity of continual hearing assessments. They must explain to parents what is known about the long-term ototoxic effects of cisplatin and how a DPOAE test in the primary care office can screen for hearing losses. Clinicians should clarify that it is only a screening test and that the results will help determine if the child needs further audiological assessment. Families and children may have difficulty talking about the cancer treatment and its persistent affect on their lives (Fuemmeler, Mullins, Van Pelt, Carpentier, & Parkhurst, 2005; Santacroce & Lee, 2006). Clinicians need to provide concrete information about the potential for hearing impairments while remaining sensitive to the family’s emotional status and coping abilities.

When referring children to audiologists, clinicians should inform families about what to expect during their appointment. The audiologist will use a battery of tests, including otoacoustic emissions, pure tone audiometry, speech audiometry, and auditory brainstem response tests to thoroughly assess the child’s hearing (ASHA, 2009b). The audiologist will measure the degree and type of hearing loss, and develop an audiogram that outlines the specific frequencies (pitch) and intensities (loudness) that the child can and cannot hear. Once the hearing profile is developed, management options will be presented.

Management of Hearing Loss

Primary care clinicians need to educate childhood cancer survivors and their families about the potential implications of hearing loss on children’s language, speech, social, and academic abilities. They need to encourage families to view hearing loss as a significant problem that must be addressed. Primary care clinicians need to be knowledgeable about the range of management options for pediatric hearing impairments. Management of children’s hearing loss will depend on its severity. Children with moderate to severe hearing impairments may require hearing aid devices and classroom accommodations, while children with mild hearing impairments may not require hearing aids but still require educational accommodations. Although hearing impairments are managed by the audiologist, the primary care clinician provides the medical home, oversees the child’s care, and acts as a resource for the family. There is a range of management options for hearing loss in children, including various hearing aids, cochlear implants, assistive listening devices, and educational accommodations.

Electronic hearing aids. There are three different types of hearing aids available for children: behind-the-ear, in-the-ear, and completely in-the-canal aids (The Children’s Hearing Institute, 2009; National Institute on Deafness and Other Communication Disorders, 2009). Behind-the-ear aids include an ear mold that sits in the outer ear and is connected to a plastic case that is placed behind the ear. With behind-the-ear aids, sounds are amplified in the plastic case and travel through the ear mold into the ear. In-the-ear aids are smaller than behind-the-ear aids, and the whole device fits into the outer ear. In general, in-the-ear aids are avoided in children because they are difficult to fit precisely in the outer ear and often need to be re-made as the child grows (The Children’s Hearing Institute, 2009). As their name implies, completely in-the-canal aids sit entirely in the ear canal and are the least visible hearing aids. Audiologists can advise families on what type of aid will work best for their child and whether the child needs an analog or digital version.

Cochlear implants. Children with severe sensorineural hearing loss may be eligible for cochlear implants. Cochlear implants involve external and internal components that are surgically inserted into the child’s cochlea (The Children’s Hearing Institute, 2009). The external part is similar to a behind-the-ear hearing aid and acts as processor and transmitter of acoustic signals, which are received by the internal component that transmits the information into electrical signals read by the cranial auditory nerve (ASHA, 2005, 2009b). Children have to undergo extensive testing by a cochlear implant center to determine their eligibility for the procedure.

Assistive listening devices. Audiologists sometimes recommend that children use assistive listening devices alone or in combination with hearing aids. One common assistive listening device is a personal frequency modulation (FM) system. Children use FM systems to aid in their hearing in group-like settings, such as school classrooms. FM systems include a microphone for the speaker to use and a portable FM receiver that looks like a small radio for the child to use. The FM receiver amplifies the sound waves so that the child can better understand the auditory input (ASHA, 2009a). Other common assistive listening devices are telephone amplification systems and one-to-one communicators.

Educational and school support for young children. Young children with hearing impairments may qualify to receive early intervention services. Primary care clinicians are responsible for referring children and their families for these services and coordinating their care. Early intervention services are critical for language and speech development (Moeller, 2000).

Educational and school support for school-age children and adolescents. Children with hearing impairments may need special accommodations for school. Primary care clinicians can collaborate with the family and school to develop an individualized education program for the child. Accommodations can include preferential classroom seating, the use of personal FM systems in the classroom, and auditory-visual curriculum adaptation. With the family’s permission, clinicians can also communicate with teachers about the child’s specific learning needs.

Resources for parents. There are several associations and Web sites that provide information about hearing impairments in children, hearing aids, and other support measures as well as promoting healthy child development (see Figure 2).

Figure 2.

Resources for Parents

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