How interaural level differences differ between children with bilateral cochlear implants and their normally-hearing peers
Reviewed by Kerri Millward & Morag Lockley

A group in the Netherlands investigated interaural level differences (ILDs) in children who were bilaterally implanted with cochlear implants (CIs) and compared their performance to their normally-hearing peers. ILDs are used to localise sound and rely on the high-frequency cues. Therefore, children with cochlear implants are likely to have a disadvantage given the period of profound hearing loss before they received their CIs. Most of the children were implanted sequentially (seven children) compared with two implanted simultaneously, which allowed the effect of inter-implant delay to be investigated. Of the four frequency bands investigated (low-pass, mid-pass, high-pass and broadband), there were no differences found between the groups on ILDs. However, for the broadband signal, children with sequentially implanted CIs showed a ILD shift towards their first implant. The shift was greater the longer the inter-implant delay. Nevertheless, this shift was not seen in a localisation task which, again, showed no difference between the two groups. This study showed that children with bilateral CIs can perform as well as their normally-hearing peers. However, implanting simultaneously or having a short inter-implant delay will maximise the binaural benefit they receive from having two CIs.

Lateralization of interaural level differences in children with bilateral cochlear implants.
Sparreboom M, Ausili SA, Mylanus EAM.
COCHLEAR IMPLANTS INT
2022;23(3):125-33.