Integrated bimodal and bilateral cochlear implant users: who performs better, and how do they compare with normal...

Adults typically receive only one cochlear implant (CI). Bimodal fitting (i.e. a contralateral hearing aid) is recommended when aidable hearing remains. However, standard hearing aids typically function independently from a CI, requiring the user to integrate disparate signals. Integrated bimodal technology has been developed to address this challenge. This study aimed to (1) to compare integrated bimodal and bilateral CI outcomes using a spatial hearing test battery that is more representative of real-life listening situations, and (2) to compare outcomes with those of adults with normal hearing.

Twenty-six CI users fitted with the integrated bimodal technology, 16 bilateral CI users and 45 normal-hearing adults were recruited. Performance and user experience were assessed using a 'real-life' spatial hearing test battery (speech perception in noise, localisation test, and tracking) and the Speech, Spatial, and Qualities-of-Hearing Scale (SSQ).

The relatively small sample size limited statistical power. No statistically significant difference was observed between the integrated bimodal and bilateral CI groups in speech-in-noise performance; however, this should not be interpreted as evidence of equivalent outcomes. Bilateral CI users demonstrated significantly better localisation (36%) and tracking (44%) performance than integrated bimodal users. Both CI groups performed significantly more poorly than the normal-hearing group. Perceived benefit of a second implant was significantly greater than that from integrated bimodal fitting.

The limited sample size precluded definitive conclusions regarding speech-in-noise differences between integrated bimodal and bilateral CI users. Bilateral CI users demonstrated significantly better spatial listening perfromace than integrated bimodal users, although outcomes remained significantly poorer than those of normal hearing adults.