To compare the speech perception benefit, provided by a contralateral hearing aid
(HA) or a second cochlear implant
A total of 25 adult subjects participated in the study, including 12 bilateral (10 female and 2 male patients) and 13 bimodal (6 female and 7 male subjects) users. All bilateral users were sequentially implanted. The bimodal users were separated into a poor group (n = 5, aided pure-tone average (PTA) of 55 dB HL or greater at audiometric frequencies of 1 kHz or lesser) and a good group (n = 8, aided PTA < 55 dB HL).
Main Outcome Measures
Consonant, vowel, and sentence recognition was measured in quiet and noise at +5 dB and +10 dB signal-to-noise ratios (SNRs). Speech recognition
performance was evaluated under three listening conditions: CI alone, HA alone, and CI+HA for bimodal users; first CI alone, second CI alone, and first CI + second CI for bilateral users when speech and noise were presented from the front.
There was no significant difference in the binaural benefit between the good bimodal and bilateral groups in vowel and sentence recognition. However, the binaural benefit is significantly better in the bilateral group than in the poor bimodal group for all 3 speech measures.
These results suggest that the aided pure-tone average at audiometric frequencies of 1 kHz or lesser may serve as one of the clinical criteria for the recommendation of whether bimodal patients should consider a second cochlear implant
to maximize their binaural listening ability.