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Objectives: To study the changes in behavioural and cortical responses over time in a child with single-sided deafness fitted with a cochlear implant (CI)., Methods: Cortical auditory evoked potentials (CAEPs) in noise (+5 dB signal-to-noise ratio) were recorded and auditory skills were assessed using tests of sound localization, spatial speech perception in noise, and self-ratings of auditory abilities (Listening inventory for education, LIFE and Speech, spatial and qualities of hearing questionnaire, SSQ parental version). Measures were obtained prior to and after a CI fitting, including one, six, and 12 months after the CI switch on., Results: Spatial speech recognition improved over time. At 12 months post-CI, word recognition scores were similar to those of normal hearing children. Signal-to-noise ratios for sentences decreased (i.e. improved) over time post-CI. Sound localization markedly improved at 12 months post-CI compared to baseline. Self-perception of difficulty scores decreased over time. Parental ratings of hearing abilities improved compared to baseline for all subscales. There were changes in the P1-N1-P2 complex at 12 months post-CI, which were clearer frontally across stimuli. Further research is needed to understand the significance of such changes after CI fitting for single-sided deafness., Conclusion: Although the changes observed could reflect maturational changes, the clinically significant improvement in recognition of speech in noise and improved questionnaire results suggest that the CI was beneficial, consistent with the feedback from the participant.

Objectives: The purpose of this study was to investigate the impact of cognition and noise reduction (NR) technology in cochlear implants (CIs) on speech perception and listening effort., Methods: Thirteen adults fitted with unilateral CIs (Nucleus ® 6, CP900) participated in this study. Participants performed: (I) cognitive tests of working memory and processing speed, (II) speech perception in noise tests, and (III) an auditory-visual dual-task paradigm to quantify listening effort, as a part of the three-phase experimental study. Both the participant and the tester, performing the outcome measures, were blinded to the NR settings (ON/OFF) of the CI for phases II and III., Results: Speech intelligibility significantly improved with the NR activated, but was independent of individual differences in cognitive abilities. Listening effort did not significantly change with NR setting; however, there was a trend for participants with good working memory to have better speech perception scores with NR activated during the effortful listening task (dual-task paradigm)., Conclusion: Future studies are warranted to explore the interaction between cognition and CI NR algorithms during an effortful listening task.

This case is of a 70-year-old man with single-sided deafness (SSD) in the right ear since childhood, who developed a sudden severe hearing loss in the left ear at the age of 63. Eventually, after he received cochlear implants in both ears, he started to present behavioural auditory processing skills associated with binaural hearing, such as improved ability to understand speech in the presence of background noise, and sound localization. Outcomes were measured using cortical auditory evoked potentials, speech perception in noise, sound localization tests, and a self-rating questionnaire. The results suggest that even after more than 50 years of unilateral deafness it was possible to develop binaural interaction and sound localization as a result of electric auditory stimulation.

Cochlear implant (CI) trends are changing as more recipients are receiving bilateral implantation. Also more pre-lingually deafened adults are choosing to be implanted. Clinical assessment after cochlear implantation is usually based on speech perception tests. Such tests, however, may not be a realistic outcome measure for some of these cases, creating a need for more objective measures of CI performance. Cortical auditory evoked potentials (CAEPs) recorded in the sound field may be a fast and reliable procedure for the clinical audiologist to determine CI outcomes. This paper presents two case studies illustrating CAEP findings in an adult CI user who was pre-lingually deafened and a bilateral CI user., (Copyright 2009 John Wiley & Sons, Ltd.)

A male with unilateral deafness in the right ear since 8 years of age developed a sudden hearing loss in the left ear at age 63. A hearing aid was fitted in the left ear with limited benefit. The right ear received a cochlear implant (CI) 20 months later. Cortical auditory evoked potentials (CAEPs) and speech recognition scores (SRS) were measured in free-field three, six and nine months after implantation with the hearing aid alone, CI alone and bimodal condition (hearing aid and CI together). Three months after implantation the cortical responses for the two ears were similar, despite more than 50 years of unilateral auditory deprivation. CAEPs measured over time show evidence of binaural interaction and improvements in SRS., (Copyright (c) 2007 John Wiley & Sons, Ltd.)