■ OBJECTIVE: To test, whether the use of experimental in-the-ear canal (ITE) microphones improves speech intelligibility and spatial discrimination in patients with bilateral cochlear implants (CIs) through preservation of auricular cues.

■ METHODS: Seven adult patients with bilateral MEDEL Combi 40+ or Pulsar CIs were fitted with experimental Tempo+ speech processors equipped with free movable, cable connected, omnidirectional microphones. On both sides simultaneously, the active microphone was either placed ITE or above/behind the ear (BTE), while a dummy microphone was placed into the other available position for blinding. Speech intelligibility was assessed in competing noise originating sequentially from four quadrants around the head using German 'Oldenburg' sentences presented from the front. Spatial discrimination was assessed in each quadrant by measuring the minimum audible angle (MAA) using a free movable, rotating boom presenting white noise bursts. No time was granted to the patients to adapt to the new processors and microphones. A Wilcoxon matched pairs signed rank test was used to compare ITE and BTE test scores.

  RESULTS: Although a trend towards better speech intelligibility in noise was found using ITE microphones, the changes were not significant. Spatial discrimination was significantly improved (p=0.031) on the side of the first implanted ear using ITE microphones (mean MAA= 28.4° ±SD =7.61°; n=7) compared to using BTE microphones (34.1±14.4°; n=7). On the side of the second CI, four out of seven patients had measurable MAAs (28.8 ±13.1°; n=4) using ITE microphones compared to two patients using BTE microphones (32±18.4°; n=2). Spatial discrimination was further non-significantly improved in front (8.43±7.6° vs. 10.1±7.1°; n=7) and in the back of the head (10.4±11.4° vs. 10.7±11.5°; n=7).