2015 HSC Section 1 Book of Articles

Objectives:

To compare the results of a “no response” (NR) result on

auditory brainstem response (ABR) testing with those of behavioral

pure-tone audiometry and ultimate clinical tracking to cochlear implan-

tation (CI).

Design:

Retrospective review of pediatric patients who underwent mul-

tifrequency ABR testing in a 5 year span. Total of 1143 pediatric patients

underwent ABR testing during the study period and 105 (9.2%) were

identified with bilateral NR based on absent responses to both click and

tone burst stimuli. For the children with NR, various clinical parameters

were evaluated as these children progressed through the CI evaluation

process. Children were grouped based on whether they underwent ABRs

for diagnostic or for confirmatory purposes.

Results:

Of the 105 children who met inclusion criteria, 94 had suffi-

cient follow-up to be included in this analysis. Ninety-one (96.8%) of

94 children with bilateral NR ABRs were ultimately recommended for

and received a CI. Three (3.2%) children were not recommended for

implantation based on the presence of multiple comorbidities rather than

auditory factors. None of the children (0%) had enough usable residual

hearing to preclude CI. For those who had diagnostic ABRs, the average

time at ABR testing was 5.4 months (SD 6.2, range 1–36) and the aver-

age time from ABR to CI was 10.78 months (SD 5.0, range 3–38).

Conclusions:

CI should tentatively be recommended for children with

a bilateral NR result with multifrequency ABR, assuming confirmatory

results with behavioral audiometric testing. Amplification trials, counsel-

ing, and auditory-based intervention therapy should commence but not

delay surgical intervention, as it does not appear to change the even-

tual clinical course. Children not appropriate for this “fast-tracking” to

implantation might include those with significant comorbidities, audi-

tory neuropathy spectrum disorder, and unreliable or poorly correlated

results on behavioral audiometric testing.

Key words:

Auditory brainstem response, Cochlear implant, Cochlear

implant candidacy, Hearing loss.

(Ear & Hearing 2015;36;8–13)

INTRODUCTION

Auditory brainstem response (ABR) testing is widely

accepted for identification and diagnosis of hearing loss in the

pediatric population. For patients who are unable to participate

in behavioral audiometry because of age or medical comorbidi-

ties, frequency-specific tone burst ABR is useful for estimat-

ing the pure-tone audiogram so that early intervention can be

implemented. There is extensive literature supporting a strong

correlation between estimated ABR and behavioral pure-tone

thresholds (Stapells 2000). However,

correlation

does not nec-

essarily imply that the test is

predictive

. In fact, there remains

a great deal of variation regarding the accuracy of ABR as a

predictor of actual behavioral thresholds. Factors that contribute

to this variation include stimulus characteristics and recording

parameters as well as developmental age and degree of hearing

loss (Sininger 2006). In one study, the inherent degree of uncer-

tainty in estimating pure-tone thresholds from ABR thresholds

with a 95% confidence levels was ±15dB HL (Stapells 2000). So

the range of pure-tone thresholds estimated from ABR thresh-

olds can be quite large with individuals in the upper limits of the

range possibly amenable to amplification (Marttila & Karikoski

2006). Furthermore, ABR estimates are generally less accurate

in the lower frequencies and in those with severe to profound

hearing loss (Gorga et al. 2006). ABR tends to overestimate the

degree of hearing loss in individuals with severe to profound

impairments (Marttila & Karikoski 2006; Sininger 2006). Thus,

even in the setting of a “no response” (NR) result on ABR test-

ing, definitive conclusions about usable residual hearing cannot

be made.

In the current management paradigm, children with congeni-

tal hearing loss and a NR result onABR testing are initially fitted

with hearing aids based on threshold estimates predicted by the

ABR with the use of a prescriptive formula for estimating gain

and output. Reliable behavioral audiometric testing is then used

to confirm pure-tone thresholds more precisely between 6 and 8

months of age and hearing aid adjustments are made as needed.

For those children who do not make appropriate progress in

communication skills development, despite good compliance

with well-fit amplification and auditory-based intervention, a

cochlear implant (CI) is recommended. When uncomplicated,

this process should result in cochlear implantation by the end of

the first year of life. This paradigm is consistent with the goals

and recommendations of the Joint Committee on Infant Hearing

(Reference Note 1).

Unfortunately, a variety of factors can and often do cause

considerable delays in access to a CI (Table 1). From an auditory

perspective, even in the setting of a bilateral NR result on ABR

testing, behavioral audiometric testing often reveals that the

degree of residual hearing might support meaningful progress

with proper fit and use of amplification. In these cases, the hear-

ing aid trial may be extended with the hope of greater progress

in lieu of exposing the child to unnecessary surgery and poten-

tial compromise of residual hearing. Moreover, for families that

are noncompliant with the early stages of the hearing aid trial,

a period of prolonged counseling and observation is often rec-

ommended to improve acceptance of the commitment needed

for success. In some cases, other medical diagnoses, including

Is “No Response” on Diagnostic Auditory Brainstem

Response Testing an Indication for Cochlear

Implantation in Children?

Anna X. Hang,

Patricia A. Roush,

Holly F. B. Teagle,

Carlton Zdanski,

Harold C. Pillsbury,

Oliver F. Adunka,

and Craig A. Buchman

Department of Otolaryngology-Head and Neck Surgery, University of

North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA; and

Division of Audiology, University of North Carolina Hospitals, Chapel

Hill, North Carolina, USA.

Reprinted by permission of Ear Hear. 2015; 36(1):8-13.

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