2015 HSC Section 1 Book of Articles

HANG ET AL. / EAR & HEARING, VOL. 36, NO. 1, 8–13

some cases, older children were referred to our institution after behavioral testing and/or ABR testing had already been per- formed. If any behavioral data had been obtained before ABR testing regardless of testing method, the ABR was considered confirmatory (cABR). Often, cABR was performed just before CI surgery to also rule out ANSD. Patients ultimately receiving bilateral CIs were noted, but analysis included only time course up to the date of the first CI. RESULTS A total of 1142 pediatric patients underwent ABR testing in the 5-year period and 105 (9.2%) met the above criteria for inclusion in the study. A summary of hearing loss etiologies and significant comorbidities can be found in Table 2. Of the 105 children identified in the review, 11 (10.5%) were lost to follow-up at the time of data collection and/or did not have reliable behavioral audiometry results. Ninety-four ( n = 94) chil- dren with NRABRs had adequate data to report with appropriate follow-up. Of the 94 patients, 80 (85.1%) failed the NBHS in at least one ear, 8 (8.5%) passed, and 6 (6.4%) did not have newborn screening data because of birth outside of the United States or adoption history. As a tertiary care medical center, many children were referred after some degree of workup or diagnosis else- where before initial evaluation at our institution. The mean age at presentation to our institution was 16.9 months (SD 25.3, range 1–137). The mean age at the time of ABR testing for all included patients was 19.3 months (SD 26.9, range 1–140). The mean age at dABR was 5.40 months (SD 6.2, range 1–36) as compared to 35.79 months (SD 28.4, range 4–131) for cABR. Although all 94 patients had an NR response on ABR test- ing at the maximum stimulus level for the frequency tested, the actual corresponding thresholds documented on behavioral testing showed a wide range of results. Figure 1 compiles the corresponding behavioral thresholds for all tested ears (175 total ears), although not all frequencies were able to be tested on both ears for all subjects. Behavioral responses at 250 Hz TABLE 2. Etiology of hearing loss and comorbidities in patients with a “no response” auditory brainstem response Etiology N (%)  Unknown 57 (54.3) Connexin 26 9 (8.6) Cytomegalovirus infection 11 (10.5) Waardenburg syndrome 7 (6.7) CHARGE syndrome 5 (4.8)  Meningitis 3 (2.9) Other congenital syndrome 5 (4.8) Inner ear malformations 29 (27.6)   Cochleo-vestibular dysplasia 18 (17.1) Enlarged vestibular aqueduct 3 (2.9) Cochlear nerve deficiency or hypoplasia 8 (7.6) Medical co-morbidities  Prematurity 20 (19.0)  Hyperbilirubinemia 11 (10.5) Neonatal intensive care unit stay 17 (16.1) Seizure disorder 9 (8.6) Developmental delay 23 (21.9) Cerebral palsy 7 (6.7) Family history of hearing loss 17 (16.1)

demonstrated a particularly broad range varying from 40 dB HL to no measurable responses. The range at higher frequen- cies showed somewhat less variability. Of the four children with thresholds 65 dB HL or better at 250 and 500 Hz, one had pro- gressive hearing loss and the remainder failed to make progress with amplification. All had a history of prematurity with three requiring mechanical ventilation in the neonatal intensive care unit. The majority of patients (>50%) with a NR ABR had no demonstrable evidence of residual hearing on behavioral testing at any of the frequencies tested. The various clinical outcomes are graphically depicted in Figure 2. Of the 94 children, 91 (96.8%) ultimately received at least one CI and 49 (52.1%) received bilateral CIs. Importantly, no child (0%) demonstrated auditory thresholds on behavioral testing or sufficient progress in speech and language develop- ment with amplification to contraindicate implantation. Of the 3 (3.2%) children who did not receive a CI, this result was sec- ondary to significant and pervasive comorbidities. For the 91 patients who ultimately went on to receive a CI, the progression through the CI evaluation process varied greatly. Two distinct patterns of progression emerged from this group based on the purpose of the initial ABR. ABRs were considered as dABR if the study was performed before any behavioral testing. If the ABR was performed with the purpose of verifying prior behavioral testing data, then it was considered as cABR. Table 3 summarizes the range, average, and SD of ages at ABR testing, behavioral testing, and CI surgery, as well as the amount of time elapsed between each of the above measures. The overall mean age at time of ABR

Fig. 1. Residual hearing as confirmed by behavioral audiometry for patients with no response on auditory brainstem response.

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