Aiding and Occluding the Contra lateral Ear in Implanted Children with Auditory Neuropathy Spectrum Disorder

Department of Otolaryngology and Communication Sciences, Medical College of Wisconsin, WI, USA.
Journal of the American Academy of Audiology (Impact Factor: 1.58). 10/2011; 22(9):567-77. DOI: 10.3766/jaaa.22.9.2
Source: PubMed


The challenges associated with auditory neuropathy spectrum disorder (ANSD) are due primarily to temporal impairment and therefore tend to affect perception of low- to midfrequency sounds. A common treatment option for severe impairment in ANSD is cochlear implantation, and because the degree of impairment is unrelated to degree of hearing loss by audiometric thresholds, this population may have significant acoustic sensitivity in the contralateral ear. Clinically, the question arises as to how we should treat the contralateral ear in this population when there is acoustic hearing-should we plug it, amplify it, implant it, or leave it alone?
The purpose of this study was to examine the effects of acute amplification and plugging of the contralateral ear compared to no intervention in implanted children with ANSD and aidable contralateral hearing. It was hypothesized that due to impaired temporal processing in ANSD, contralateral acoustic input would interfere with speech perception achieved with the cochlear implant (CI) alone; therefore, speech perception performance will decline with amplification and improve with occlusion.
Prospective within-subject comparison. Adaptive speech recognition thresholds (SRTs) for monosyllable and spondee word stimuli were measured in quiet and in noise for the intervention configurations.
Nine children treated at the Medical College of Wisconsin Koss Cochlear Implant Program participated in the study. Inclusion criteria for this study were children diagnosed with ANSD who were unilaterally implanted, had aidable hearing in the contralateral ear (defined as a three-frequency pure-tone average of ≤80 dB HL), had at least 1 yr of cochlear implant experience, and were able to perform the speech perception task.
We compared SRT with the CI alone to SRTs with interventions of cochlear implant with a contralateral hearing aid (CI+HA) and cochlear implant with a contralateral earplug (CI+plug).
SRTs were measured and compared within subjects across listening conditions. Within-subject comparisons were analyzed using paired t-tests, and analyses of predictive variables for effects of contralateral intervention were analyzed using linear regression.
Contrary to the hypothesis, the bimodal CI+HA configuration showed a significant improvement in mean performance over the CI-alone configuration in quiet (p = .04). In noise, SRTs were obtained for six subjects, and no significant bimodal benefit was observed (p = .09). There were no consistent effects of occlusion observed across subjects and stimulus conditions. Degree of bimodal benefit showed a significant relationship with performance with the CI alone, with greater bimodal benefit associated with poorer CI-alone performance (p = .01). This finding, however, was limited by floor effects.
The results of this study indicate that children with ANSD who are experienced cochlear implant users may benefit from contralateral amplification, particularly for moderate cochlear implant performers. It is unclear from these data whether long-term contralateral hearing aid use in real-world situations would ultimately benefit this population; however, a hearing aid trial is recommended with assessment of bimodal benefit over time. These data may help inform clinical guidelines for determining optimal hearing configurations for unilaterally implanted children with ANSD, particularly when considering candidacy for sequential cochlear implantation.

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    • "Substantial across-patient variations in aided speech perception skills have been reported for children with ANSD. Some patients demonstrate speech perception in quiet and spoken language abilities that are comparable to their matched peers with sensorineural hearing loss (Deltenre et al. 1999; Rance et al. 1999 2002; Rance & Baker 2008, 2009; Berlin et al. 2010; Runge et al. 2011). In contrast, many patients fail to show significant improvement in speech "
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    ABSTRACT: The overall aim of the study was to evaluate the feasibility of using electrophysiological measures of the auditory change complex (ACC) to identify candidates for cochlear implantation in children with auditory neuropathy spectrum disorder (ANSD). To achieve this overall aim, this study (1) assessed the feasibility of measuring the ACC evoked by temporal gaps in a group of children with ANSD across a wide age range and (2) investigated the association between gap detection thresholds (GDTs) measured by the ACC recordings and open-set speech-perception performance in these subjects. Nineteen children with bilateral ANSD ranging in age between 1.9 and 14.9 years (mean: 7.8 years) participated in this study. Electrophysiological recordings of the auditory event-related potential (ERP), including the onset ERP response and the ACC, were completed in all subjects and open-set speech perception was evaluated for a subgroup of 16 subjects. For the ERP recordings, the stimulus was a Gaussian noise presented through ER-3A insert earphones to the test ear. Two stimulation conditions were used. In the "control condition," the stimulus was an 800-msec Gaussian noise. In the "gapped condition," the stimuli were two noise segments, each being 400 msec in duration, separated by one of five gaps (i.e., 5, 10, 20, 50, or 100 msec). The interstimulation interval was 1200 msec. The aided open-set speech perception ability was assessed using the Phonetically Balanced Kindergarten (PBK) word lists presented at 60 dB SPL using recorded testing material in a sound booth. For speech perception tests, subjects wore their hearing aids at the settings recommended by their clinical audiologists. For a subgroup of five subjects, psychophysical GDTs for the Gaussian noise were also assessed using a three-interval, three-alternative forced-choice procedure. Responses evoked by the onset of the Gaussian noise (i.e., onset responses) were recorded in all stimulation conditions from all subjects tested in this study. The presence/absence, peak latency and amplitude, and response width of the onset response did not correlate with aided PBK word scores. The objective GDTs measured with the ACC recordings from 17 subjects ranged from 10 to 100 msec. The ACC was not recorded from two subjects for any gap durations tested in this study. There was a robust negative correlation between objective GDTs and aided PBK word scores. In general, subjects with prolonged objective GDTs showed low-aided PBK word scores. GDTs measured using electrophysiological recordings of the ACC correlated well with those measured using psychophysical procedures in four of five subjects who were evaluated using both procedures. The clinical application of the onset response in predicting open-set speech-perception ability is relatively limited in children with ANSD. The ACC recordings can be used to objectively evaluate temporal resolution abilities in children with ANSD having no severe comorbidities, and who are older than 1.9 years. The ACC can potentially be used as an objective tool to identify poor performers among children with ANSD using properly fit amplification, and who are thus, cochlear implant candidates.
    No preview · Article · Nov 2014 · Ear and Hearing
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    • "This suggested that the residual hearing in the ear contralateral to the CI was in some way facilitating the patient ' s ability to localize sound sources prior to receiving a second implant. This fi nding is consistent with the unexpected fi nding of bimodal listening benefi t described by Runge et al, (2011). "
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    ABSTRACT: Objective: The neural dys-synchrony associated with auditory neuropathy spectrum disorder (ANSD) causes a temporal impairment that could degrade spatial hearing, particularly sound localization accuracy (SLA) and spatial release from masking (SRM). Unilateral cochlear implantation has become an accepted treatment for ANSD but treatment options for the contralateral ear remain controversial. We report spatial hearing measures in a child with ANSD before and after receiving a second cochlear implant (CI). Study sample: An 11-year-7-month old boy with ANSD and expressive and receptive language delay received a second CI eight years after his first implant. Design: The SLA and SRM were measured four months before sequential bilateral CIs (with the contralateral ear plugged and unplugged), and after nine months using both CIs. Results: Testing done before the second CI, with the first CI alone, suggested that residual hearing in the contralateral ear contributed to sound localization accuracy, but not word recognition in quiet or noise. Nine-months after receiving a second CI, SLA improved by 12.76° and SRM increased to 3.8-4.2 dB relative to pre-operative performance. Results were compared to published outcomes for children with bilateral CIs. Conclusions: The addition of a second CI in this child with ANSD improved spatial hearing.
    Full-text · Article · Apr 2013 · International journal of audiology
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    ABSTRACT: Spatial release from masking (SRM) was measured in groups of children with bilateral cochlear implants (BiCIs, average ages 6.0 and 7.9 yr) and with normal hearing (NH, average ages 5.0 and 7.8 yr). Speech reception thresholds (SRTs) were measured for target speech in front (0°), and interferers in front, distributed asymmetrically toward the right (+90°/+90°) or distributed symmetrically toward the right and left (+90°/-90°). In the asymmetrical condition both monaural "better ear" and binaural cues are available. In the symmetrical condition, listeners rely heavily on binaural cues to segregate sources. SRM was computed as the difference between SRTs in the front condition and SRTs in either the asymmetrical or symmetrical conditions. Results showed that asymmetrical SRM was smaller in BiCI users than NH children. Furthermore, NH children showed symmetrical SRM, suggesting they are able to use binaural cues for source segregation, whereas children with BiCIs had minimal or absent symmetrical SRM. These findings suggest that children who receive BiCIs can segregate speech from noise under conditions that maximize monaural better ear cues. Limitations in the CI devices likely play an important role in limiting SRM. Thus, improvement in spatial hearing abilities in children with BiCIs may require binaural processing strategies.
    No preview · Article · Jul 2012 · The Journal of the Acoustical Society of America
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