Objective: To compare speech understanding with bimodal hearing and bilateral cochlear implants (CIs).
Study design: Within-subjects, repeated-measures.
Methods: Speech understanding was assessed in the following conditions: unilateral hearing aid (HA) in the non-implanted ear, unilateral CI, bimodal (CI + HA), and bilateral CI. In addition, three participants had bilateral hearing preservation and were also tested with bilateral CIs and bilateral HAs (BiBi).
Setting: Tertiary academic CI center.
Patients: Eight adult sequential bilateral recipients who, despite achieving incredibly high performance with the first CI, self-selected for bilateral cochlear implantation.
Intervention(s): Bilateral cochlear implantation.
Main outcome measure(s): Speech understanding for the adult minimum speech test battery as well as sentences in semidiffuse noise using the R-SPACE system.
Results: Bilateral CIs afforded significant individual improvement in a complex listening environment even for individuals demonstrating near perfect sentence scores with both the first CI alone as well as the bimodal condition. The 3 BiBi participants demonstrated additional significant benefit over the bilateral CI condition-presumably because of the availability of interaural time difference cues.
Conclusions: These data suggest that, for noisy environments, adding a second implant can significantly improve speech understanding-even for high-performing unilateral CI with bimodal hearing. In diffuse noise conditions, bilateral acoustic hearing can yield even greater benefits beyond that offered by bilateral implantation.