Diagnostic Challenges and Safety Considerations in Cochlear Implantation Under the Age of 12 Months
International Journal of Pediatric Otorhinolaryngology
Vlastarakos, P. V., Candiloros, D., et al. (2010).
International Journal of Pediatric Otorhinolaryngology, 74(2), 127-132.
This systematic review investigates the diagnostic, surgical, and anesthetic challenges associated with cochlear implantation (CI) in children before the age of 12 months. Of particular interest to audiologists is the assessment and diagnosis of hearing loss to determine candidacy for CI.
Not stated
1982 to December 2008
Not further specified
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Behavioral audiometry, including visual reinforcement audiometry, is not applicable for determining candidacy for cochlear implantation in young infants or children with additional disorders or complications (e.g. prematurity). Depending on the child, behavioral audiometry can be attempted during postoperative fitting and tuning.
While otoacoustic emissions (OAEs) are useful as a hearing screening tool, they are not adequate for discriminating level of severity of hearing loss (i.e., moderate, severe, profound hearing loss) to identify cochlear implant candidacy in young children. Additionally OAEs<ul> <li>display overlapping results between hearing loss and typical hearing, and</li> <li>require additional analysis tools to improve the sensitivity and specificity.</li></ul>
Assessment of preverbal skills provides indirect and additional information about the cochlear implant candidate. “The examination of complex prelinguistic vocalization types by measures of vocal development is necessary to document the progress of children who are expected to acquire speech at later-than-typical ages (such as infant implantees)” (p. 129).
Auditory steady state responses (ASSRs) demonstrate better specificity than auditory brainstem responses (ABRs) and demonstrate more objectivity in predicting auditory responses. While ASSRs produce variable results during the first weeks of life, ASSRs completed after the neonatal period “have been found to highly correlate to behavioural hearing levels obtained later in childhood” (p. 128) in both children with typical hearing and with hearing loss. ASSRs are considered a “promising assessment method in identifying our target population for pediatric cochlear implant surgery” (p. 128).
While auditory brainstem responses (ABR) “are considered an objective technique for the assessment of hearing thresholds” (p. 128), “the determination of waveforms and the estimated level of hearing can be subjective” (p. 128) when determining candidacy for cochlear implantation. Because ABRs test a narrow range of frequency, cases with useful residual hearing (e.g. normal hearing or mild hearing loss in low frequencies) may be missed.
"The diagnosis of profound hearing loss in infancy, although challenging, can be confirmed with acceptable certainty when objective measures...are combined" (p. 131) when determining cochlear implant candidacy.
After diagnostic evaluations, additional considerations for cochlear implant candidacy in newborns with hearing loss include:<ul> <li>anatomical constraints,</li> <li>existing comorbidities (e.g. otitis media with effusion), and</li> <li>device parameters.</li></ul>
