This study revisits the issue of the spectral ripple resolution abilities of cochlear implant (CI) users. The spectral ripple resolution of recently implanted CI recipients (implanted during the last 10 years) were compared to those of CI recipients implanted 15 to 20 years ago, as well as those of normal-hearing and hearing-impaired listeners from previously published data from Henry, Turner, and Behrens [J. Acoust. Soc. Am. 118, 1111–1121 (2005)]. More recently, implanted CI recipients showed significantly better spectral ripple resolution. There is no significant difference in spectral ripple resolution for these recently implanted subjects compared to hearing-impaired (acoustic) listeners. The more recently implanted CI users had significantly better pre-operative speech perception than previously reported CI users. These better pre-operative speech perception scores in CI users from the current study may be related to better performance on the spectral ripple discrimination task; however, other possible factors such as improvements in internal and external devices cannot be excluded.
Measuring nascent macromolecular synthesis in vivo is key to understanding how cells and tissues progress through development and respond to external cues. Here we perform in vivo injection of alkyne- or azide-modified analogs of thymidine, uridine, methionine, and glucosamine to label nascent synthesis of DNA, RNA, protein, and glycosylation. Three-dimensional volumetric imaging of nascent macromolecule synthesis was performed in axolotl salamander tissue using whole-mount click chemistry-based fluorescent staining followed by light sheet fluorescent microscopy. We also developed an image processing pipeline for segmentation and classification of morphological regions of interest and individual cells, and we apply this pipeline to the regenerating humerus. We demonstrate our approach is sensitive to biological perturbations by measuring changes in DNA synthesis after limb denervation. This method provides a powerful means to quantitatively interrogate macromolecule synthesis in heterogenous tissues at the organ, cellular, and molecular levels of organization.
Remote microphones serve as assistive devices with the potential to enhance speech perception and sound quality for cochlear implant (CI) users in challenging listening environments. However, the extent to which adult CI users and their communication partners perceive these benefits remains uncertain. To address this question, we organized support groups for adult CI recipients implanted at the University of Iowa Hospitals and Clinics and their partners residing. The primary objectives of these support groups were twofold: firstly, to provide comprehensive education on the benefits of utilizing remote microphones, and secondly, to facilitate discussions on pertinent topics, including troubleshooting device-related issues. This study focuses on identifying and addressing the barriers encountered by adult CI users and their communication partners in effectively utilizing remote microphones, while simultaneously promoting their proper use through education and guidance. During the support group sessions, we engaged in discussions focused on strategies for optimizing remote microphone utilization among CI users and their frequent communication partners. These strategies encompassed comprehensive education and training, technical assistance, addressing concerns and potential stigma, and involving family members and caregivers in the process. Following participation in the support group sessions, all attendees completed questionnaires indicating an increased motivation to utilize remote microphones effectively. This finding underscores the critical role of education and support in promoting the efficient use of assistive devices and ultimately enhancing communication outcomes for both CI recipients and their communication partners. In summary, this project indicates the potential advantages of incorporating remote microphones into the lives of adult CI recipients and their communication partners. It underscores the imperative need for robust education and support mechanisms to ensure the optimal utilization of remote microphone systems.
Nucleus Hybrid Cochlear Implant (CI) users hear low-frequency sounds via acoustic stimulation and high-frequency sounds via electrical stimulation. This within-subject study compares three different methods of coordinating programming of the acoustic and electrical components of the Hybrid device. Speech perception and cortical auditory evoked potentials (CAEP) were used to assess differences in outcome. The goals of this study were to determine whether (1) the evoked potential measures could predict which programming strategy resulted in better outcome on the speech perception task or was preferred by the listener, and (2) CAEPs could be used to predict which subjects benefitted most from having access to the electrical signal provided by the Hybrid implant.CAEPs were recorded from 10 Nucleus Hybrid CI users. Study participants were tested using three different experimental processor programs (MAPs) that differed in terms of how much overlap there was between the range of frequencies processed by the acoustic component of the Hybrid device and range of frequencies processed by the electrical component. The study design included allowing participants to acclimatize for a period of up to 4 weeks with each experimental program prior to speech perception and evoked potential testing. Performance using the experimental MAPs was assessed using both a closed-set consonant recognition task and an adaptive test that measured the signal-to-noise ratio that resulted in 50% correct identification of a set of 12 spondees presented in background noise. Long-duration, synthetic vowels were used to record both the cortical P1-N1-P2 "onset" response and the auditory "change" response (also known as the auditory change complex [ACC]). Correlations between the evoked potential measures and performance on the speech perception tasks are reported.Differences in performance using the three programming strategies were not large. Peak-to-peak amplitude of the ACC was not found to be sensitive enough to accurately predict the programming strategy that resulted in the best performance on either measure of speech perception. All 10 Hybrid CI users had residual low-frequency acoustic hearing. For all 10 subjects, allowing them to use both the acoustic and electrical signals provided by the implant improved performance on the consonant recognition task. For most subjects, it also resulted in slightly larger cortical change responses. However, the impact that listening mode had on the cortical change responses was small, and again, the correlation between the evoked potential and speech perception results was not significant.CAEPs can be successfully measured from Hybrid CI users. The responses that are recorded are similar to those recorded from normal-hearing listeners. The goal of this study was to see if CAEPs might play a role either in identifying the experimental program that resulted in best performance on a consonant recognition task or in documenting benefit from the use of the electrical signal provided by the Hybrid CI. At least for the stimuli and specific methods used in this study, no such predictive relationship was found.
Regulation of cell cycle progression is essential for cell proliferation during regeneration following injury. After appendage amputation, the axolotl (Ambystoma mexicanum) regenerates missing structures through an accumulation of proliferating cells known as the blastema. To study cell division during blastema growth, we generated a transgenic line of axolotls that ubiquitously expresses a bicistronic version of the fluorescent ubiquitination-based cell-cycle indicator (FUCCI). We demonstrate near-ubiquitous FUCCI expression in developing and adult tissues, and validate these expression patterns with DNA synthesis and mitosis phase markers. We demonstrate the utility of FUCCI for live and whole-mount imaging, showing the predominantly local contribution of cells during limb and tail regeneration. We also show that spinal cord amputation results in increased proliferation at least 5 mm from the site of injury. Finally, we use multimodal staining to provide cell type information for cycling cells by combining fluorescence in situ hybridization, EdU click-chemistry and immunohistochemistry on a single FUCCI tissue section. This new line of animals will be useful for studying cell cycle dynamics using in situ endpoint assays and in vivo imaging in developing and regenerating animals.
Introduction: Expanding cochlear implant (CI) candidacy criteria and advances in electrode arrays and soft surgical techniques have increased the number of CI recipients who have residual low-frequency hearing. Objective measures such as obligatory cortical auditory-evoked potentials (CAEPs) may help clinicians make more tailored recommendations to recipients regarding optimal listening mode. As a step toward this goal, this study investigated how CAEPs measured from hybrid CI users differ in two listening modes: acoustic alone (A-alone) versus acoustic plus electric (A + E). Methods: Eight successful hybrid CI users participated in this study. Two CAEPs, the P1-N1-P2 and the acoustic change complex (ACC), were measured simultaneously in response to the onset and change of a series of different and spectrally complex acoustic signals, in each of the two listening modes (A-alone and A + E). We examined the effects of listening mode and stimulus type on the onset and ACC N1-P2 amplitudes and peak latencies. Results: ACC amplitudes in hybrid CI users significantly differed as a function of listening mode and stimulus type. ACC responses in A + E were larger than those in the A-alone mode. This was most evident for stimuli involving a change from low to high frequency. Conclusions: Results of this study showed that the ACC varies as a function of listening mode and stimulus type. This finding suggests that the ACC can be used as a physiologic, objective measure of the benefit of hybrid CIs, potentially supporting clinicians in making clinical recommendations on individualized listening mode, or to document subjective preference for a given listening mode. Further research into this potential clinical application in a range of hybrid recipients and/or long electrode users who have residual low-frequency hearing is warranted.
Purpose: Unilateral cochlear implant (CI) recipients with limited hearing in the contralateral ear are deprived of the advantages of binaural hearing. To address speech recognition challenges arising from the head shadow effect, a contralateral routing of signal (CROS) device can be used; however, less is known of the broader impact of a CROS device on an individual's quality of life (QoL) or that of their frequent communication partners (FCPs). This preliminary study aimed to evaluate the impact of CROS on speech recognition in noise and its influence on the QoL of unilateral CI recipients and their FCPs. Method: This preliminary study enrolled seven adult unilateral CI recipients and their FCPs. All CI recipients were fitted with CROS devices during their initial appointments. Speech recognition testing was conducted in noise with and without the CROS device in a sound booth before a take-home trial. Participants used the CROS devices for approximately 1 year, with device fitting occurring before and continuing during the COVID-19 pandemic. Participants completed two QoL questionnaires, the Auditory Performance and Satisfaction Scale for Single-Sided Deafness (APS-SSD) and the Nijmegen Cochlear Implant Questionnaire (NCIQ), twice: once prior to CROS device use and once after the take-home trial. Additionally, the FCPs of each CI recipient completed the Significant Other Scale of Hearing Disability (SOS-HEAR) Questionnaire twice, once before and once after extended CROS device use. Results: When noise was directed toward the CI ear and speech toward the non-CI ear, speech recognition improved by 32% with the CROS device ( p = .001). CI recipients reported significant median improvement in the “general” domain of the APS-SSD after the take-home trial (Wilcoxon Z = 12.0, p < .05). FCPs reported a significant median reduction in concerns related to their partner's hearing when the CI recipient used the CROS device (Wilcoxon Z = 2.0, p < .05). Conclusions: This preliminary study demonstrates the benefit of CROS devices for unilateral CI recipients in noisy environments. Additionally, it highlights the positive impact of CROS devices on the QoL of both CI recipients and their FCPs. These findings emphasize the importance of considering CROS devices as a valuable solution for unilateral CI recipients to enhance their hearing experience, overall well-being, and that of their FCPs.
Objectives: The purposes of this study were (1) to determine the reliability of the Korean version of the Scale of Parental Involvement and Self-efficacy-Revised (SPISE-R-K), (2) to examine whether rehabilitation experience and residual hearing level have an impact on parental self-efficacy and their involvement in rehabilitation processes, and (3) to describe the early intervention for young children with hearing loss (CHL) and their caregivers in Korea by analyzing the items in the SPISE-R-K. Methods: We collected 61 SPISE-R-K questionnaires from the caregivers of CHL (mean age = 20.85 months, SD = 7.85; male = 33, female = 28). All children used hearing devices (hearing aid (s) users = 36; cochlear implant (s) users = 25). The reliability of the questionnaire was assessed, and the effects of rehabilitation experience, and children’s residual hearing were examined for the sub-sections of ‘Knowledge’, ‘Confidence’ and ‘Action’. Moreover, the item scores from each section were compared. Results: Cronbach’s α analyses indicated that the SPISE-R-K was reliable in measuring the self-efficacy and involvement of caregivers of CHL. We found that the rehabilitation experience did not show a significant effect on each section’s score whereas residual hearing level had a significant effect on the ‘Knowledge’ section scores. Overall, parents showed higher self-efficacy in items related to auditory access than in items related to language development. Conclusion: The SPISE-R-K is a reliable tool for measuring the self-efficacy and involvement of Korean caregivers of young CHL. We hope that professionals utilize SPISE-R-K to identify the information that needs to be provided to caregivers of young Korean children with hearing loss, making it a valuable tool for early intervention.
