Comparison of sound localisation ability in bimodal versus bilateral cochlear implant users

To compare the sound localisation abilities of bimodal cochlear implant and bilateral cochlear implant users.

A horizontal sound source discrimination task was conducted with 44 and 20 bimodal and bilateral cochlear implant users, respectively. Paired and two-sample t-tests were performed for paired and unpaired data, respectively.

The root mean square error scores of the bimodal cochlear implant and bilateral cochlear implant users were 75.77 ± 10.49° and 54.39 ± 19.82°, respectively. The bilateral cochlear implant users' root mean square error score was significantly better than that of the bimodal cochlear implant users (t = 5.65, p < 0.001). The root mean square error scores of bimodal cochlear implant users with good and poor low-frequency hearing were 75.45 ± 11.07° and 76.10 ± 10.14°, respectively, with no significant intergroup difference (t = 0.20, p = 0.84).

Bilateral cochlear implantation may be more helpful for sound localisation in patients with bilateral sensorineural hearing loss. The better low-frequency hearing threshold of the non-implanted ears did not result in better sound localisation ability in bimodal cochlear implant users.