Speech Performance and Sound Localization Abilities in Neurelec Digisonic® SP Binaural Cochlear Implant Users

In this prospective study the outcome of the Digisonic (R) SP Binaural cochlear implant (CI), a device enabling electric stimulation of both cochleae by a single receiver, was evaluated in 14 postlingually deafened adults after 12 months of use. Speech perception was tested using French disyllabic words in quiet and in speech-shaped noise at +10 dB signal-to-noise ratio. Horizontal sound localization in quiet was tested using pink noise coming from 5 loudspeakers, from -90 to +90 degrees along the azimuth. Speech scores in quiet were 76% (+/- 19.5 SD) in the bilateral condition, 62% (+/- 24 SD) for the better ear alone and 43.5% (+/- 27 SD) for the poorer ear alone. Speech scores in noise were 60% (+/- 27.5 SD), 46% (+/- 28 SD) and 28% (+/- 25 SD), respectively, in the same conditions. Statistical analysis showed a significant advantage of the bilateral use in quiet and in noise (p < 0.05 compared to the better ear). Significant spatial perception benefits such as summation effect (p < 0.05), head shadow effect (p < 0.0001) and squelch effect (p < 0.0005) were noted. Sound localization accuracy improved significantly when using the device in the bilateral condition with an average root mean square of 35 degrees. Compared with published outcomes of usual bilateral cochlear implantation, this device could be a valuable alternative to two CIs. Prospective controlled trials, comparing the Digisonic SP Binaural CI with a standard bilateral cochlear implantation are mandatory to evaluate their respective advantages and cost-effectiveness. Copyright (C) 2012 S. Karger AG, Basel