Speech Understanding and Subjective Listening Effort in Noise With Different OTEs and Sound Processing Technologies.

OBJECTIVE: To determine speech reception thresholds (SRTs) in noise and subjective listening effort (LE) in cochlear implant (CI) recipients for application of three sound processing (SP) technologies with two off-the-ear (OTE) CI sound processors, a fixed moderately directional microphone (Standard), an adaptive directional microphone (Beam), and the spatial noise-reduction setting ForwardFocus, with the Kanso 2 (OTE2), and Beam with the Kanso (OTE1). STUDY DESIGN: Prospective repeated measures, within-subject design. SETTING: Single tertiary-referral center. PATIENTS: Twenty CI recipients with bilateral severe-to-profound sensorineural hearing loss. MAIN OUTCOME MEASURES: SRTs were assessed in two spatial configurations with frontal speech and noise from 90-180-270 degrees (S0N90-180-270) or from the CI side (S0NCI). SRTs were obtained for sentences of the Oldenburg sentence test presented in International Collegium of Rehabilitative Audiology (ICRA) noise ICRA5-250. LE for speech understanding in noise was evaluated in S0N90-180-270 and assessed in effort scale categorical units (ESCUs) by using Adaptive Categorical Listening Effort Scaling (ACALES). LEs at 5-dB signal-to-noise ratio (SNR) were calculated from fitted psychometric curves. RESULTS: With OTE2 in S0N90-180-270, SRT with ForwardFocus (-4.28 dB SNR) was better than with Beam (-3.13 dB SNR) and Standard (0.43 dB SNR). ForwardFocus showed lower LE5dB (2.61 ESCU) compared with Beam (4.60 ESCU) and Standard (5.32 ESCU). In a comparison of both OTEs in S0N90-180-270 regarding best-performing SP technology, ForwardFocus with OTE2 yielded a better SRT and better LE5dB than Beam with OTE1 (SRT: -1.70 dB SNR; LE5dB: 4.00 ESCU). With OTE2 in S0NCI, SRT was improved with ForwardFocus (-2.78 dB SNR) compared with Beam (-1.23 dB SNR) and Standard (1.83 dB SNR). CONCLUSION: With respect to SP technology and OTE, CI recipients experience best SRT and lowest LE in S0N90-180-270 when using ForwardFocus with OTE2. ACALES is feasible for assessing subjective LE in CI recipients.

Speech Perception in Quiet and Noise With an Off the Ear CI Processor Enabling Adaptive Microphone Directionality.

OBJECTIVE: To investigate the impact of the wearing position of an off-the-ear-processor (OTE) on speech perception in quiet and noise. PATIENTS: The study group consisted of 16 adult subjects with bilateral severe-to-profound sensorineural hearing loss, 2 of them unilaterally, and 14 bilaterally provided with cochlear implants. MAIN OUTCOME MEASURES: Speech perception in quiet and noise was measured for frontal presentation with the recipients behind-the-ear processor CP810 or CP910 and the OTE processor Kanso (Cochlear Limited, Sydney, Australia). Additionally, speech performance in noise with the OTE for spatially separated signal and noise sources was assessed. RESULTS: The recipients showed monosyllabic word recognition scores in quiet between 65 and 95% and speech reception thresholds in noise between 2.4 and -5.5 dB SNR with the OTE. For frontal presentation of speech and noise, application of the adaptive directional microphone (Beam) yielded a slight median decrement of 0.6 dB for the speech reception threshold compared with standard directionality. However, huge median improvements, ranging from -3.7 to -11.6 dB, for the three tested conditions with spatially separated sources (S0NIL, S0NCL, S0N180) were observed. CONCLUSION: The beamforming algorithm in the investigated OTE processor provides similar benefits as described in previous studies for behind-the-ear processors in conditions with spatially separated speech and noise sources. Adaptive microphone directionality can be successfully implemented in an OTE processor. The OTE processor's potential to increase usability, comfort, and cosmetics might not be compromised by a deterioration of speech performance.

The benefits of sequential bilateral cochlear implantation for hearing-impaired children.

CONCLUSION: Sequential bilateral implantation offers listening advantages demonstrable on speech recognition in noise and for lateralization. Whilst the trend was for shorter inter-implant intervals and longer implant experience to positively impact binaural advantage, we observed no contraindications for binaural advantage. OBJECTIVE: To evaluate the benefits of sequential bilateral cochlear implantation over unilateral implantation in a multicentre study evaluating speech recognition in noise and lateralization of sound. SUBJECTS AND METHODS: Twenty children, implanted bilaterally in sequential procedures, had the following characteristics: they were native German-speaking, were3 years or older and had a minimum of 1 year inter-implant interval and had between 2 months and 4 years 7 months binaural listening experience. Binaural advantage was assessed including speech recognition in noise using the Regensburg modification of the Oldenburger Kinder-Reimtest (OLKI) and lateralization of broadband stimuli from three speakers. RESULTS: A significant binaural advantage of 37% was observed for speech recognition in noise. Binaural lateralization ability was statistically superior for the first and second implanted ear (p = 0.009, p = 0.001, respectively). Binaural experience was shown to correlate moderately with absolute binaural speech recognition scores, with binaural advantage for speech recognition and with binaural lateralization ability. The time interval between implants correlated in an inverse direction with binaural advantage for speech recognition.