Better-ear glimpsing in Japanese adult bilateral cochlear implant users

Abstract

Better-ear glimpsing (BEG) is a phenomenon that helps understanding speech in the presence of fluctuating, spatially separated distractors. This phenomenon has been studied in normal-hearing (NH) and hearing-impaired listeners but remains untapped in adults with cochlear implants (CIs). Further, it has not been investigated how far providing CIs in both ears can improve BEG over providing a single CI in one ear. In the current study, seven Japanese adult bilateral CI users with post-lingual deafness were recruited. Male and female speech distractors were presented from + 900 and—900 and target questions taken from the Helen sentence test (translated into Japanese, spoken by a native Japanese female speaker) were presented from the front. Speech comprehension thresholds (SCTs) were measured in both a co-located and spatially separated condition with CIs in both ears and only in one ear. BEG was calculated as the difference in SCTs between the co-located and spatially separated condition. BEG noted with bilateral CIs was about 2 dB and with unilateral CI was about 0.3 dB, which is significantly smaller than found in NH listeners. The bilateral benefit noted was about 3 dB indicating the advantage of having CIs in both the ears.