Importance of Age and Postimplantation Experience on Speech Perception Measures in Children With Sequential Bilateral Cochlear Implants

Abstract

Sequential bilateral cochlear implantation in children of diverse ages has the potential to improve speech perception abilities in the second implanted ear and to provide access to the use of binaural mechanisms such as the head shadow effect. The improvement unfolds over time and continues to grow during the 6 to 12 months after activation of the second implant. Younger children in this study achieved higher open-set speech perception scores in the second ear, but older children still demonstrate bilateral benefit in noise. Determining the long-term impact and cost-effectiveness that results from such potential capabilities in bilaterally implanted children requires additional study with larger groups of subjects and more prolonged monitoring.

Contrasting benefits from contralateral implants and hearing aids in cochlear implant users

“…While such measures may be inflated by better ear contributions, the greater experience with the first-implanted ear (CI-1) means it is more likely to be the ear with better performance, at least for sequentially implanted children with longer intervals between ears. Results generally indicate that the benefit in quiet is in approximate agreement with adult outcomes (Kühn-Innacker et al, 2004;Bohnert et al, 2006;Peters et al, 2007;Zeitler et al, 2008;Kim et al, 2009;Gordon and Papsin, 2009;Scherf et al, 2009a;Sparreboom et al, 2011). For co-located speech and noise, benefits are marginally larger than in quiet, and are also larger than for adults tested in noise possibly due to better ear contributions.…”

“…Schafer and Thibodeau (2006) presented sentences from 0 and two uncorrelated multi-classroom recordings at 135 and 225 and found a bilateral SRT benefit of 2 dB relative to the first-implanted ear, which allowing for better ear contributions appears in approximate agreement with the adult binaural benefit that is on the order of 1 dB. Several studies have described longitudinal speech outcomes in BiCI children delineated according to age at implantation in one or both ears (Peters et al, 2007;Wolfe et al, 2007;Gordon and Papsin, 2009;Scherf et al, 2009a;Sparreboom et al, 2011). Monaural performance is generally more similar between ears when children are implanted early, and the delay between implantations is small or absent.…”

“…Occasionally larger benefits (Litovsky et al, 2006b;Wolfe et al, 2007) may be attributable to high subject variation or experimental methods that lead to an increased role of loudness summation. For spatially separated speech and noise the monaural benefit due to the head-shadow approaches that found in adults (Litovsky et al, 2006b;Peters et al, 2007;Galvin et al, 2007Galvin et al, , 2008Steffens et al, 2008). However the binaural benefit obtained when adding later implanted ear (CI-2) at a favorable SNR appears smaller than predicted by the head-shadow result, presumably because performance is often poorer with CI-2 than CI-1.…”

Bilateral Simultaneous Cochlear Implantation in Children: Report of a Case and Review of Literature

“…Bilateral paediatric CI is becoming common in clinical practice. Benefit appears to be gained if a second implant is provided after a short interval and in as young an age group as possible [2,4]. Based on research published regarding the plasticity and maturation of the auditory system in mammals and the presence of sensitive or critical periods for hearing and speech development, it is plausible to assume the presence of critical periods for the development of binaural hearing and the optimal bilateral integration of both ears [5].…”

Speech-perception-in-noise and bilateral spatial abilities in adults with delayed sequential cochlear implantation

“…It is a modest bilateral benefit with effects up to 2 dB, although some reports indicate no effect or even negative effects Laszig et al, 2004;Litovsky et al, 2006). Bilateral implantation can be divided into the following categories: (i) simultaneous implantation where both ears are implanted during the same surgical procedure; (ii) sequential implantation with interimplant intervals between 6 and 12 months on average; and (iii) delayed sequential implantation with inter-implant intervals of more than 2 years (Manrique, Huarte, Valdivieso & Pérez, 2007;Peters, Litovsky, Parkinson & Lake, 2007). In the South African context simultaneous implantation is not yet routinely employed.…”