Lateralization of Interaural Level Differences with Multiple Electrode Stimulation in Bilateral Cochlear-Implant Listeners.
Olga A Stakhovskaya, Matthew J Goupell
PMID 27579987WHAT IT FOUND
Bilateral cochlear implant users often hear sounds intended to be centered in the head as shifted to one side.
Adjusting electrode levels to correct these biases significantly reduced them, potentially improving spatial hearing.
Key findings
01Bilateral cochlear implant listeners showed substantial variability in perceiving the location of sounds, with 44% of single-electrode measurements having a bias of at least 5 current units away from the center.
02Adjusting current levels on individual electrode pairs to correct for these biases significantly reduced the proportion of large biases in multi-electrode stimulation from 25% to 4%.
03Normal-hearing listeners perceived zero-level differences as centered, whereas bilateral cochlear implant listeners did not, indicating a fundamental difference in how spatial cues are processed between the groups.
STILL TO COME
How it was doneWhat they found
Read the rest of this summary
You get three full summaries a month, free, and we do not ask for a card. Search, the TL;DRs and your library stay unlimited either way.
What it does not show
The study used research processors, not standard clinical devices, so the results may not directly translate to current clinical mapping software. The sample size was small (9 BiCI listeners), and there was high variability between individuals. The comparison between NH and BiCI groups is complicated by the lack of a direct way to equate acoustic decibels to electrical current units. The study did not measure actual sound localization accuracy in real-world environments, only intracranial lateralization perception.
Declared interests
The study was supported by NIH/NIDCD grants. The authors declared no conflicts of interest.
The easy way to misread this
Do not assume this centering procedure is ready for clinical use. It was performed with research processors and did not test whether the adjustments negatively impacted speech understanding or audibility in the other ear.