Subjective inter-aural differences in pitch perception related to depth of electrode array insertion after sequential bilateral cochlear implants.

This paper will present a case study of a post-lingually deaf adult who reported a significant difference in pitch perception between the two ears after receiving sequential bilateral cochlear implants. In spite of one ear sounding lower in pitch than the other, speech perception tests using open set sentences showed maximum scores in each individual ear. Inter-aural comparison of pitch perception of every electrode in each ear confirmed patient's report that one side sounded lower in pitch than the other. Imaging studies of the petrous temporal bones using high resolution CT-scans revealed cochlear implant electrode array insertion to be deeper in the ear with lower pitch perception in comparison to the side with higher pitch perception. Interestingly, 6 months after consistent usage of bilateral cochlear implants, the difference in pitch between the two ears was no longer noticed suggesting that neural plasticity had taken place. [ABSTRACT FROM AUTHOR]