Challenges of Cochlear Implant Use for Spatial Hearing in Children and Adolescents With Asymmetric Hearing Including Single Sided Deafness.
Robel Z Alemu, Alan Blakeman, Jaina Negandhi and 4 others
Children with a cochlear implant in one ear and hearing in the other still cannot reliably locate sounds or track their direction.
The implant helps a little for stationary sounds on the implanted side but does not restore normal spatial hearing.
Key findings
1Stationary sound localization error was significantly greater in bimodal listeners than in children with normal hearing, and perception of moving sound direction was significantly reduced. Turning the cochlear implant on did not improve moving-sound accuracy at all.
2Sensitivity to interaural level differences was reduced and sensitivity to interaural timing differences was significantly impaired in bimodal listeners. These cue deficits were associated with poorer stationary and moving sound localization, but the association held only across groups, not within the cochlear implant group alone.
3Later onset of hearing loss was associated with reduced error in stationary sound localization and more acute perception of movement direction, suggesting that having normal binaural hearing in early childhood matters for later spatial hearing with a cochlear implant.
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What it does not show
Small sample: 34 bimodal listeners and only 5–6 controls per task, so subgroup comparisons (hearing-aid-plus-implant vs single-sided deafness) have limited power. Cross-sectional design: all measurements were taken at one time point, so it is impossible to tell whether spatial hearing improves with more cochlear implant experience or whether the children are still developing. The children used their own clinically programmed cochlear implants, which were set for comfortable sound rather than optimized for binaural cue access, so the spatial hearing results may underestimate what better programming could achieve. Interaural level differences were created by equal changes in decibels on the acoustic side and cochlear implant units on the implant side, which the authors acknowledge may reduce measured sensitivity. No data on daily device use or compliance were collected, and inconsistent use is known to affect outcomes. No adaptation period was tested; the authors note that normal-hearing adults can reduce spatial hearing errors over three days with a monaural plug, but this was not explored here. Data from 12 participants had been published previously in related papers.
Declared interests
The authors declared no financial support and no conflicts of interest.
The easy way to misread this
Do not read the finding that the cochlear implant reduces asymmetry on the implanted side as evidence that the implant adequately addresses spatial hearing. Overall localization errors remained comparable to a child with one ear plugged, moving-sound direction was significantly impaired with no benefit from the implant (p = 0.99), and binaural cue access was still severely limited. The implant helps a little in one specific condition but does not restore the spatial hearing these children need for a classroom or playground.
Summarised by AI from the full paper, without a clinician reviewing it. Check it against the source before it changes what you do. Read it on PubMed →