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The value of ASSR threshold-based bilateral hearing aid fitting in children with difficult or unreliable behavioral audiometry.

Abstract

We conducted an analysis to assess the relative contribution of auditory brainstem response (ABR) testing and auditory steady-state response (ASSR) testing in providing appropriate hearing aid fitting in hearing-impaired children with difficult or unreliable behavioral audiometry. Of 150 infants and children who had been referred to us for hearing assessment as part of a neonatal hearing screening and cochlear implantation program, we identified 5 who exhibited significant discrepancies between click-ABR and ASSR testing results and difficult or unreliable behavioral audiometry. Hearing aid fitting in pediatric cochlear implant candidates for a trial period of 3 to 6 months is a common practice in many implant programs, but monitoring the progress of the amplified infants and providing appropriate hearing aid fitting can be challenging. If we accept the premise that we can assess the linguistic progress of amplified infants with an acceptable degree of certainty, the auditory behavior that we are monitoring presupposes appropriate bilateral hearing aid fitting. This may become very challenging in young children, or even in older children with difficult or unreliable behavioral audiometry results. This challenge can be addressed by using data from both ABR and ASSR testing. Fitting attempts that employ data from only ABR testing provide amplification that involves the range of spoken language but is not frequency-specific. Hearing aid fitting should also incorporate and take into account ASSR data because reliance on ABR testing alone might compromise the validity of the monitoring process. In conclusion, we believe that ASSR threshold-based bilateral hearing aid fitting is necessary to provide frequency-specific amplification of hearing and appropriate propulsion in the prelinguistic vocalizations of monitored infants.

Introduction

Early cochlear implantation in children has a positive effect on the development of the auditory pathways, as well as on postimplantation outcomes. (1,3) Delays in detecting severe hearing impairment can significantly impair the development of verbal communication skills and spoken language. Thus, the implementation of universal screening of neonatal hearing is the only way to achieve very early detection of deafness and a timely referral to a cochlear implant center if need be. (4,5)

It is common practice to fit pediatric cochlear implant candidates who are identified by neonatal screening with bilateral hearing aids for a trial period of 3 to 6 months. If these patients do not progress linguistically, then cochlear implantation can be considered. Another rationale for fitting hearing aids in severely or even profoundly deaf infants is to provide some access to the normal auditory spectrum, taking advantage of the critical periods of neuroplasticity. (6,7)

The aforementioned practice in cochlear implant programs should satisfy two important prerequisites: (1) provision of appropriate hearing aid fitting and (2) monitoring the linguistic progress of the amplified infants. Both aspects can be challenging in hard-of-hearing children.

In this article, we describe our case series in which we assessed the relative contributions of auditory brainstem response (ABR) testing and auditory steady-state response (ASSR) testing in facilitating appropriate hearing aid fitting for hearing-impaired children in whom behavioral audiometry was difficult or unreliable.

Patients and methods

Over a period of 5.5 years, we assessed the hearing of 150 infants and children who had been referred to the Clinic of Pediatric Hearing Loss at Attikon University Hospital in Athens as part of a neonatal hearing screening and cochlear implantation program. The children underwent a full ENT examination, tympanometry, transient evoked otoacoustic emissions (TEOAEs) measurements, and automated ABR testing. A detailed medical and family history was also taken.

Those children whose hearing failed the initial assessment were subsequently subjected to more TEOAE measurements in addition to click-evoked ABR testing and mixed-modulation ASSR testing (90 Hz sleeping-child default mode) while they were under sedation with 4% chloral hydrate (maximum dose: 1.5 mg/kg) or, for older children, hydroxyzine HC1 (10 mg/5 ml) under the guidance of a pediatrician.

Children with mild to moderate hearing loss were fitted with bilateral hearing aids and referred for speech and occupational therapy. Children with severe to profound or deteriorating hearing loss also underwent radiologic evaluation with computed tomography and magnetic resonance imaging, and they were referred for genetic testing for connexin-26 protein. They were also referred for multidisciplinary assessment in the various specialties of the cochlear implantation program. Finally, they were fitted with hearing aids for a 3--to 6-month trial.

Results

Among the 150 tested children, 5 presented with significant discrepancies between their ABR and ASSR test results (table). In these 5 children, either (1) behavioral audiometry was too difficult to be performed or (2) its results were unreliable. In these cases, hearing aid fitting was based on the information obtained by both ABR threshold testing and ASSR-predicted audiograms (figures 1 and 2).

By study's end, the ensuing linguistic progress of these children did not necessitate cochlear implantation in any of them.

Discussion

It is widely accepted that a patients age at the time of hearing aid fitting and cochlear implantation is a significant predictor of the development of speech perception and intelligibility in deaf children. (7,11) This fact--coupled with (1) a growing body of evidence that supports providing implants to very young children (<12 mo), (1,2) (2) improvements in technology, (12) and (3) an enhanced awareness regarding the safety of cochlear implantation in young children (13)--has led to an increasing trend toward shortening the delay of auditory access to spoken language for pediatric cochlear implant candidates.

Even though it is frequently fraught with difficulty, hearing aid fitting in pediatric cochlear implant candidates for a trial period of 3 to 6 months is common practice in many implant programs. This approach appears to be necessary for children who present with a bilateral hearing loss between 65 and 85 dB. The findings of a study by Leigh et al suggest that for severely deaf children, cochlear implantation offers a chance of about a 75% greater improvement in hearing com pared with bilateral hearing aids. (14) If such a chance of improvement is probable, then cochlear implantation should be considered for hearing-impaired children who fail to demonstrate linguistic progress during a hearing aid trial. If linguistic progress during the trial is demonstrated, cochlear implantation can be postponed or cancelled.

In view of the challenges encountered in a hearing aid trial, we should note that objective outcomes of hearing amplification in infancy are usually considered to be "soft," as they are in the vast majority subjective and often indirect (i.e., assessing parental views), (15,16) or may even easily reach a ceiling effect in some cases. (17)

The development of communication skills in hearing-impaired infants can be assessed by examining their preverbal communication skills. (18) Preverbal behaviors are natural precursors of language development in all children, irrespective of their hearing status. These behaviors include appropriate eye contact, conversational-style turn-taking, autonomy, and auditory awareness of the sound of speech. (18) They form the normal pattern of language development, which begins in early infancy.

The Tait video analysis is a fine example of a methodology for assessing preverbal communication in infants. (18,19) It can also be used to monitor the development of vocal and auditory preverbal skills in very young deaf children who have been using acoustic hearing aids.

If we accept the premise that we can assess the linguistic progress of amplified infants with an acceptable degree of reliability, the auditory behavior that we are monitoring presupposes appropriate bilateral hearing aid fitting. Fitting might become very challenging in young children, and even in older children whose behavioral audiometry is unreliable due to limited cooperation or other disabilities. However, even this challenge could be addressed by using data from ABR and/or ASSR testing.

Considering the vague and non-frequency-specific information obtained from click ABRs, it is obvious that fitting attempts based on these data may not address the hearing needs of amplified children; even worse, they might lead to unpleasant or even harmful hearing. Therefore, click ABR testing should not be the only method of monitoring children's preverbal progress, especially in cases where behavioral audiometry is unreliable.

Even though tone-burst-evoked ABRs have been used to estimate the configuration of hearing loss in children, technical issues along with the amount of time needed to record electrophysiologic thresholds seem to limit their applicability. (20) Hence, hearing aid fitting should take into account ASSR data to ascertain the validity of the fitting and monitoring processes.

Our case series involves a subpopulation of hearing-impaired children with significant discrepancies between the results of their ABR and ASSR tests. These discrepancies might prove to be challenging for appropriate hearing aid fitting when reliable behavioral audiometry is not available. For example, in our patient 3, the 70-dB ABR threshold waveform referred to the 4.0-kHz frequency only (figures 1 and 2). The remaining frequencies appeared to be normal or borderline. Fitting this child with a uniform amplification of 55 to 60 dB in all frequencies likely would have resulted in intolerance to the use of the hearing aids, which would understandably hinder the child's auditory and vocal progress. If this were to pose a problem for a 2-year-old such as our patient 3, the issue could be even more serious in infants due to the limitations mentioned above, and it could compromise the validity of the monitoring process.

The idea that ASSRs might be a more accurate predictor of behavioral thresholds than are ABRs in certain patients with steeply sloping hearing loss has been previously supported by other investigators. (21,22) ASSR thresholds can be used to predict the configuration of pure-tone audiometry, (23,24) which would contribute to an appropriate bilateral hearing aid fitting in hard-of-hearing infants. However, the potential difference between pure-tone and ASSR thresholds in the hearing-impaired population--which usually does not exceed 7 dB ([+ or -]5), depending on the frequency (25,26)--should also be considered, both during the fitting process and when determining cochlear implant candidacy.

In conclusion, appropriate management of hearing-impaired children should ensure that they will receive the maximum amount of auditory information during the critical periods for spoken language development and thereby achieve age-appropriate spoken language skills to the closest extent possible. Moreover, we must ensure that a reliable monitoring process is established for the group of children who are in a hearing aid trial before cochlear implantation. To achieve this, especially in children with difficult or unreliable behavioral audiometry, ASSR threshold-based bilateral hearing aid fitting is necessary to provide frequency-specific amplification of hearing and appropriate propulsion in the prelinguistic vocalizations of monitored infants.

Petros V. Vlastarakos, MD, MSc, PhD; Alexandra Vasileiou, MD; Thomas P. Nikolopoulos, MD, DM, PhD

From the ENT Department, MITERA Paediatric Infirmary, Athens, Greece (Dr. Vlastarakos); the Clinic of Pediatric Hearing Loss (Dr. Vasileiou) and the ENT Department (Prof. Nikolopoulos), Attikon University Hospital, Athens. The study described in this article was conducted at the Attikon University Hospital.

Corresponding author: Dr. Petros V. Vlastarakos, ENT Department, MITERA Paediatric Infirmary, 6 Erythrou Stavrou Str., Athens 15123, Greece. Email: pevlast@hotmail.com

References

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(2.) Colletti L, Mandala M, Zoccante L, et al. Infants versus older children fitted with cochlear implants: Performance over 10 years. Int J Pediatr Otorhinolaryngol 2011;75(4):504-9.

(3.) Silva LA, Couto MI, Tsuji RK, et al. Auditory pathways' maturation after cochlear implant via cortical auditory evoked potentials. Braz J Otorhinolaryngol 2014;80(2):131-7.

(4.) Vlastarakos PV, Candiloros D, Papacharalampous G, et al. Diagnostic challenges and safety considerations in cochlear implantation under the age of 12 months. Int J Pediatr Otorhinolaryngol 2010;74(2): 127-32.

(5.) Vlastarakos PV, Kalampalikis E. The impact of the economic crisis on neonatal hearing screening in Greece. Cent Eur J Public Health 2015;23(l):85-6.

(6.) Yoshinaga-Itano C. Early intervention after universal neonatal hearing screening: Impact on outcomes. Ment Retard Dev Disabil Res Rev 2003;9(4):252-66.

(7.) Yoshinaga-Itano C, Sedey AL, Coulter DK, Mehl AL. Language of early- and later-identified children with hearing loss. Pediatrics 1998;102(5):1161-71.

(8.) Tait ME, Nikolopoulos TP, Lutman ME. Age at implantation and development of vocal and auditory preverbal skills in implanted deaf children. Int J Pediatr Otorhinolaryngol 2007;71(4):603-10.

(9.) Nikolopoulos TP, Dyar D, Gibbin KP. Assessing candidate children for cochlear implantation with the Nottingham Childrens Implant Profile (NChIP): The first 200 children. Int J Pediatr Otorhinolaryngol 2004;68(2):127-35.

(10.) O'Donoghue GM, Nikolopoulos TP, Archbold SM. Determinants of speech perception in children after cochlear implantation. Lancet 2000;356(9228):466-8.

(11.) Nikolopoulos TP, O'Donoghue GM, Archbold S. Age at implantation: Its importance in pediatric cochlear implantation. Laryngoscope 1999;109(4):595-9.

(12.) Schauwers K, Gillis S, Daemers K, et al. Cochlear implantation between 5 and 20 months of age: The onset of babbling and the audiologic outcome. Otol Neurotol 2004;25(3):263-70.

(13.) Colletti V, Carner M, Miorelli V, et al. Cochlear implantation at under 12 months: Report on 10 patients. Laryngoscope 2005;115(3):445-9.

(14.) Leigh J, Dettman S, Dowell R, Sarant J. Evidence-based approach for making cochlear implant recommendations for infants with residual hearing. Ear Hear 2011;32(3):313-22.

(15.) Rossetti L. The Rossetti Infant-Toddler Language Scale. East Moline, 111.: LinguiSystems; 2006.

(16.) Robbins AM, Renshaw JJ, Berry SW. Evaluating meaningful auditory integration in profoundly hearing-impaired children. Am J Otol 1991;12(Suppl):144-50.

(17.) Sininger YS, Grimes A, Christensen E. Auditory development in early amplified children: Factors influencing auditory-based communication outcomes in children with hearing loss. Ear Hear 2010;31(2):166-85.

(18.) Tait ME, Nikolopoulos TP, Wells P, White A. The use and reliability of Tait video analysis in assessing preverbal language skills in profoundly deaf and normally hearing children under 12 months of age. Int J Pediatr Otorhinolaryngol 2007;71(9):1377-82.

(19.) Tait DM. Video analysis: A method of assessing changes in preverbal and early linguistic communication after cochlear implantation. Ear Hear 1993;14(6):378-89.

(20.) Pinto FR, Matas CG. A comparison between hearing and tone burst electrophysiological thresholds. Braz J Otorhinolaryngol 2007;73(4):513-22.

(21.) Lin YH, Ho CH, Wu HP. Comparison of auditory steady-state responses and auditory brainstem responses in audiometric assessment of adults with sensorineural hearing loss. Auris Nasus Larynx 2009;36(2):140-5.

(22.) Johnson TA, Brown CJ. Threshold prediction using the auditory steady-state response and the tone burst auditory brain stem response: A within-subject comparison. Ear Hear 2005;26(6): 559-76.

(23.) Venema T. The ASSR revisited: A clinical comparison of two stimuli. The Hearing Review website. http://www.hearingreview. com/2005/06/the-assr-revisited-a-clinical-comparison-of-twostimuli/. Published June 4, 2005. Accessed Sept. 7, 2017.

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(25.) Beck RM, Ramos BF, Grasel SS, et al. Comparative study between pure tone audiometry and auditory steady-state responses in normal hearing subjects. Braz J Otorhinolaryngol 2014;80(1): 35-40.

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Caption: Figure 1. The ABR thresholds of patient 3 clearly identify wave V at 70 dB HL.

Caption: Figure 2. The ASSR-predicted audiogram of patient 3 clearly demonstrates the difference in ABR thresholds. (The numbers at the bottom of the figure refer to the percentage probability that the patient can hear at the corresponding dB HL.)
Table. General and audiologic characteristics of children
presenting with significant discrepancies between
ABR and ASSR test results

                                    kHz

                     ABRs,      ASSRs, right
                     dBHL

Pt.    Age    OAEs    R/L    0.5   1.0   2.0   4.0
       (yr)

1       5     N/A    50/80   40    10    25    20

2      2.5    Fail   60/60   30    40    40    40

3       2     N/A    70/70   25    15    35    70

4       5     Fail   40/50   35    45    60    55

5      3.7    Fail   60/80   35    15    20    10

                kHz

            ASSRs, left

Pt.    0.5   1.0   2.0   4.0   Remarks

1      80    65    60    65    Patient had received
                               intravenous antibiotics for
                               pneumonia

2      30    35    45    40    Patient had sisters with SNHL

3      20    20    30    65    Patient had hyperbilirubinemia
                               and was admitted to the NICU

4      75    65    80    55    Patient had lower-limb
                               hypotonia and increased
                               white-matter signal

5      90    90    90    90    One member of patient's
                               maternal family had
                               pediatric SNHL

Key: OAEs = otoacoustic emissions; ABRs = auditory brainstem responses;
ASSRs = auditory steady-state responses; SNHL = sensorineural hearing
loss; NICU = neonatal intensive care unit.
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Title Annotation:ORIGINAL ARTICLE
Author:Vlastarakos, Petros V.; Vasileiou, Alexandra; Nikolopoulos, Thomas P.
Publication:Ear, Nose and Throat Journal
Date:Dec 1, 2017
Words:2761
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