Hearing In Cochlear Implant Users Research Articles

Cognitive Functions and Subjective Hearing in Cochlear Implant Users.

: A cochlear implant (CI) is an effective prosthetic device used to treat severe-to-profound hearing loss. The present study examined cognitive function in CI users by employing a web-based cognitive testing platform, i.e., BrainCheck, and explored the correlation between cognitive function and subjective evaluation of hearing. : Forty-two CI users (mean age: 58.90 years) were surveyed in the subjective evaluation of hearing, and 20/42 participated in the BrainCheck cognitive tests (immediate recognition, Trail Making A, Trail Making B, Stroop, digit symbol substitution, and delayed recognition). As controls for cognitive function, young normal-hearing (YNH, mean age=23.83 years) and older normal-hearing (ONH, mean age=52.67 years) listener groups were subjected to Brain- Check testing. : CI users exhibited poorer cognitive function than the normal hearing groups in all tasks except for immediate and delayed recognition. The highest percentage of CI users who had "possible" and "likely" cognitive impairment, based on BrainCheck scores (ranging from 0-200), was observed in tests assessing executive function. The composite cognitive score across domains tended to be related to subjective hearing (p=0.07). : The findings of the current study suggest that CI users had a higher likelihood of cognitive impairment in the executive function domain than in lower-level domains. BrianCheck online cognitive testing affords a convenient and effective tool to self-evaluate cognitive function in CI users.

Spatial Hearing in Cochlear Implant Users Improves With Training Protocol

Spatial Hearing in Cochlear Implant Users Improves With Training Protocol

Electro-Haptic Enhancement of Spatial Hearing in Cochlear Implant Users

Cochlear implants (CIs) have enabled hundreds of thousands of profoundly hearing-impaired people to perceive sounds by electrically stimulating the auditory nerve. However, CI users are often very poor at locating sounds, which leads to impaired sound segregation and threat detection. We provided missing spatial hearing cues through haptic stimulation to augment the electrical CI signal. We found that this “electro-haptic” stimulation dramatically improved sound localisation. Furthermore, participants were able to effectively integrate spatial information transmitted through these two senses, performing better with combined audio and haptic stimulation than with either alone. Our haptic signal was presented to the wrists and could readily be delivered by a low-cost wearable device. This approach could provide a non-invasive means of improving outcomes for the vast majority of CI users who have only one implant, without the expense and risk of a second implantation.

Neurophysiological evidence of impaired musical sound perception in cochlear-implant users

Objective Music perception with a cochlear implant (CI) can be unsatisfactory because current-day implants are primarily designed to enable speech discrimination. The present study aimed at evaluating electrophysiological correlates of musical sound perception in CI users to help achieve the long-term goal of improved restoration of hearing in those individuals. Methods Auditory discrimination accuracy in adult CI users ( n = 12) and matched normal-hearing controls ( n = 12) was measured by behavioral discrimination tasks and mismatch negativity (MMN) recordings. Discrimination profiles were obtained by using a set of clarinet sounds (original/vocoded) varying along different acoustic dimensions (frequency/intensity/duration) and deviation magnitudes (four levels). Results Behavioral results and MMN recordings revealed reduced auditory discrimination accuracy in CI users. An inverse relationship was found between MMN amplitudes and duration of profound deafness. Conclusions CI users have difficulties in discriminating small changes in the acoustic properties of musical sounds. The recently developed multi-feature MMN paradigm ( Pakarinen et al., 2007) can be used to objectively evaluate discrimination abilities of CI users for musical sounds. Significance Measuring auditory discrimination functions by means of a multi-feature MMN paradigm could be of substantial clinical value by providing a comprehensive profile of the extent of restored hearing in CI users.

Effects of introducing unprocessed low-frequency information on the reception of envelope-vocoder processed speech

This study investigated the benefits of adding unprocessed low-frequency information to acoustic simulations of cochlear-implant processing in normal-hearing listeners. Implant processing was simulated using an eight-channel noise-excited envelope vocoder, and low-frequency information was added by replacing the lower frequency channels of the processor with a low-pass-filtered version of the original stimulus. Experiment 1 measured sentence-level speech reception as a function of target-to-masker ratio, with either steady-state speech-shaped noise or single-talker maskers. Experiment 2 measured listeners' ability to identify two vowels presented simultaneously, as a function of the F0 difference between the two vowels. In both experiments low-frequency information was added below either 300 or 600 Hz. The introduction of the additional low-frequency information led to substantial and significant improvements in performance in both experiments, with a greater improvement observed for the higher (600 Hz) than for the lower (300 Hz) cutoff frequency. However, performance never equaled performance in the unprocessed conditions. The results confirm other recent demonstrations that added low-frequency information can provide significant benefits in intelligibility, which may at least in part be attributed to improvements in F0 representation. The findings provide further support for efforts to make use of residual acoustic hearing in cochlear-implant users.