A Longitudinal Study in Children With Sequential Bilateral Cochlear Implants: Time Course for the Second Implanted Ear and Bilateral Performance

Abstract

a Purpose: Whether, and if so when, a second-ear cochlear implant should be provided to older, unilaterally implanted children is an ongoing clinical question. This study evaluated rate of speech recognition progress for the second implanted ear and with bilateral cochlear implants in older sequentially implanted children and evaluated localization abilities. Method: A prospective longitudinal study included 24 bilaterally implanted children (mean ear surgeries at 5.11 and 14.25 years). Test intervals were every 3-6 months through 24 months postbilateral. Test conditions were each ear and bilaterally for speech recognition and localization.Results: Overall, the rate of progress for the second implanted ear was gradual. Improvements in quiet continued through the second year of bilateral use. Improvements in noise were more modest and leveled off during the second year. On all measures, results from the second ear were poorer than the first. Bilateral scores were better than either ear alone for all measures except sentences in quiet and localization. Conclusions: Older sequentially implanted children with several years between surgeries may obtain speech understanding in the second implanted ear; however, performance may be limited and rate of progress gradual. Continued contralateral ear hearing aid use and reduced time between surgeries may enhance outcomes. Bilateral cochlear implantation in children has become more prevalent (Peters, Wyss, & Manrique, 2010) with sequential implantation more common than simultaneous procedures. The dominance of sequential implantation has been driven by the many unilateral pediatric cochlear implant (CI) recipients who were implanted before bilateral implantation was considered and the fact that worldwide, the majority of children continue to be implanted unilaterally (Cullington, Bele, Brinton, & Lutman, 2013;Peters et al., 2010). During the decision process for individual children about second-side implantation, clinicians and families must consider the type and extent of benefit to be expected, for both the second implanted ear and bilaterally, and the rate of improvement to expect after varied years of unilateral CI experience.Pediatric studies have focused on bilateral compared with unilateral performance in the same individual using one of three study designs: bilateral compared with the first implanted (CI1) ear, bilateral compared to the better performing ear (Galvin, Mok, & Dowell, 2007;Kim et al., 2009;Kühn-Inacker, Shehata-Dieler, Müller, & Helms, 2004;Wolfe et al., 2007), or bilateral compared with each ear individually (Galvin, Hughes, & Mok, 2010;Galvin, Mok, Dowell, & Briggs, 2008;Peters, Litovsky, Parkinson, & Lake, 2007;Steffens et al., 2008; for reviews of pediatric sequential bilateral studies, see Dowell et al., 2011;Johnston, Durieux-Smith, Angus, O'Connor, & Fitzpatrick, 2009;Lammers, Venekamp, Grolman, & van der Heijden, 2014;Sparreboom et al., 2010). Most published studies report results from a single time point with participants having varied amounts ...

Unilateral Hearing Loss: Understanding Speech Recognition and Localization Variability—Implications for Cochlear Implant Candidacy

“…Whether later implantation of a congenital, unilaterally deaf ear is as viable as early implantation of that ear is unknown at this time. Bilaterally implanted children and adults with delayed second-ear implantation have reduced binaural benefits due to extended periods of unilateral hearing (Gordon et al 2013; Litovsky and Gordon 2016; Litovsky and Misurelli 2016; Ramsden et al 2005; Reeder et al 2016; Reeder et al 2014). Collectively, these studies suggest potential compromises to binaural benefits of cochlear implantation for individuals with prolonged unilateral deafness.…”

Auditory Attention and Spatial Unmasking in Children With Cochlear Implants

“…Today, many children who are deaf receive BiCIs, in part, to help overcome difficulties associated with listening in noisy environments. Although multiple studies show improvement on spatial hearing tasks for children with BiCIs versus children with unilateral CIs ( Bennett & Litovsky, 2020 ; Cullington et al., 2017 ; Galvin et al., 2007 ; Grieco-Calub & Litovsky, 2010 , 2012 ; Litovsky et al., 2004 ; Murphy et al., 2011 ; Reeder et al., 2017 ; Suneel et al., 2020 ; Zheng et al., 2015 ), there are still notable gaps in performance between children with BiCIs and children with NH. When target speech and interfering speech are spatially separated, children with BiCIs typically demonstrate smaller benefits (i.e., spatial unmasking) compared with NH peers who are matched for either chronological age or for number of years of auditory experience ( Hess et al., 2018 ; Misurelli & Litovsky, 2012 , 2015 ).…”

Sound Localization in Toddlers with Normal Hearing and with Bilateral Cochlear Implants Revealed Through a Novel “Reaching for Sound” Task

“…A common thread in studies with bilaterally implanted children is that regardless of the delay in implantation between the ears, they generally perform more poorly than NH peers Grieco-Calub and Litovsky, 2010;Misurelli and Litovsky, 2012;2015;Zheng et al, 2015;Dorman et al, 2016;Cullington et al, 2017;Reeder et al, 2017). A notable feature in previous studies is that children were aged four years or older, and in many cases, their hearing was not bilaterally activated until age three years or older.…”