Speech Perception Changes in the Acoustically Aided, Nonimplanted Ear after Cochlear Implantation: A Multicenter Study.

In recent years there has been an increasing percentage of cochlear implant (CI) users who have usable residual hearing in the contralateral, nonimplanted ear, typically aided by acoustic amplification. This raises the issue of the extent to which the signal presented through the cochlear implant may influence how listeners process information in the acoustically stimulated ear. This multicenter retrospective study examined pre- to postoperative changes in speech perception in the nonimplanted ear, the implanted ear, and both together. Results in the latter two conditions showed the expected increases, but speech perception in the nonimplanted ear showed a modest yet meaningful decrease that could not be completely explained by changes in unaided thresholds, hearing aid malfunction, or several other demographic variables. Decreases in speech perception in the nonimplanted ear were more likely in individuals who had better levels of speech perception in the implanted ear, and in those who had better speech perception in the implanted than in the nonimplanted ear. This raises the possibility that, in some cases, bimodal listeners may rely on the higher quality signal provided by the implant and may disregard or even neglect the input provided by the nonimplanted ear.

Speech Perception Outcomes for Adult Cochlear Implant Recipients Using a Lateral Wall or Perimodiolar Array.

AIM: To assess the speech perception outcomes of adult CI recipients with significant preimplant low frequency hearing, examining differences between perimodiolar and lateral wall electrode placement in order to provide clinical guidance for clinicians and surgeons. METHODS: A prospective cohort study was undertaken identifying all adults who received a thin straight electrode array (TSEA) at the Royal Victorian Eye & Ear Hospital (RVEEH) from 2010 to 2015 and who had a preimplant low frequency pure tone median ≤70 dB HL (n = 63). A retrospective review was completed of the RVEEH database to identify a comparison group who had been implanted with a perimodiolar electrode array, comprising adults implanted between 2004 and 2011 (PM Group) with preimplant hearing equivalent to the TSEA group (n = 70). The TSEA Group were further divided into subgroups in which n = 19 used EAS (TSEA-EAS) and n = 44 who used electric-only hearing (TSEA-Standard). RESULTS: There was no significant difference in median speech perception outcomes between the TSEA and PM Groups (TSEA 61.7%, PM 67.3%, p = 0.954). A significant difference was found between the TSEA-EAS and TSEA-Standard subgroups for median speech perception outcome (TSEA-EAS median 73.5%, TSEA-Standard median 58.3%, p = 0.043). CONCLUSIONS: Significant speech perception benefit following cochlear implantation was achieved with both the perimodiolar and lateral wall electrode arrays and no significant difference was found between outcomes with those array types in this population of adults with functional low frequency hearing pre-implant. Those that received a TSEA, had preserved hearing, and utilised an EAS sound processor performed better than their peers with a TSEA and electric-only hearing.

Hearing Preservation Outcomes for 139 Cochlear Implant Recipients Using a Thin Straight Electrode Array.

OBJECTIVE: To assess the hearing preservation outcomes in a large group of adult cochlear implant recipients implanted with a thin straight electrode array using atraumatic surgical techniques. Factors affecting hearing preservation will be investigated. STUDY DESIGN: Prospective cohort study undertaken at the Royal Victorian Eye and Ear Hospital in Melbourne, Australia from December 2010 to May 2015. SETTING: Tertiary academic hospital. PATIENTS: One hundred thirty-nine adults undergoing cochlear implantation (CI). MAIN OUTCOME MEASURE: Primary outcome measure of interest was pre and postoperative pure-tone audiometry. RESULTS: Median low-frequency hearing change for the whole group of 139 recipients was -22.5 dB at the 3 months postop point. Eighty-six participants had functional preoperative low-frequency hearing (≤70 dB average at 250 and 500 Hz). Of these, 90.7% retained measureable hearing at 3 months postimplant. 39.5% of this original 86 participants retained functional hearing at 3 months postimplant. At 12 months postimplant, those who retained functional hearing at 3 months had no significant change in hearing. The group who lost functional hearing continued to have a significant deterioration in low-frequency hearing. Degree of hearing loss preimplant was identified as a predictor for the preservation of hearing postoperatively. CONCLUSION: Preservation of hearing is possible following atraumatic cochlear implant surgery with a thin straight electrode array. The amount of hearing preserved seems to be variable, and factors related to this variability are not yet known. The results of the present study suggest preoperative low-frequency hearing at or better than 45 dB may be related to preservation of functional hearing.

Exposure to polychlorinated biphenyl-153 decreases incidence of autoimmune Type 1 diabetes in non-obese diabetic mice.

Type 1 diabetes (T1D) incidence has been steadily rising across the globe. Exposure to persistent organic pollutants (POP) has been implied as one potential cause of increased T1D occurrence. Since data regarding the role of POP polychlorinated biphenyl-153 (PCB-153) in autoimmune T1D development in experimental animal models are lacking, this study sought to evaluate the effect of PCB-153 exposure on T1D development in a non-obese diabetic (NOD) mouse model. As T1D is an autoimmune, T-cell-dependent disease, PCB-153 effects on T-cells were studied as well. Pre-diabetic 8-9-week-old NOD mice were exposed to intraperitoneal injections of PCB-153 in a 10-day short- (subacute exposure; 0.5 or 50 mg/kg) or 16-week long-term (subchronic exposure; 0.125 or 12.5 mg/kg) fashion. A significant decrease in incidence of T1D was observed in both low- and high-dose subchronically exposed mice. Analysis of various immune parameters, including T-cell types and subtypes, T-cell proliferative responses - as well as their cytokine secretions, revealed that both short- and long-term exposure to PCB-153 caused significant immunosuppression. PCB-153-induced immunosuppression was reflected in reductions in levels of T helper (TH)-type cells and their functions after subacute treatment with low- and high-dose PCB-153. In agreement, decreased levels of TH cells, reduced proliferation and IL-2 secretion seemed to be a mechanism of PCB-153 action in the development of T1D in subchronically exposed mice. In conclusion, this study for the first time revealed the effects of PCB-153 on development of T1D, bridging the existing experimental knowledge gap regarding the association of non-dioxin-like PCBs and T1D.

Music appreciation and music listening in prelingual and postlingually deaf adult cochlear implant recipients.

OBJECTIVE: To explore the music appreciation of prelingually deaf adults using cochlear implants (CIs). DESIGN: Cohort study. Adult CI recipients were recruited based on hearing history and asked to complete the University of Canterbury Music Listening Questionnaire (UCMLQ) to assess each individual's music listening and appreciation. Results were compared to previous responses to the UCMLQ from a large cohort of postlingually deaf CI recipients. STUDY SAMPLE: Fifteen prelingually deaf and 15 postlingually deaf adult cochlear implant recipients. RESULTS: No significant differences were found between the prelingual and postlingual participants for amount of music listening or music listening enjoyment with their CI. Sound quality of common instruments was favourable for both groups, with no significant difference in the pleasantness/naturalness of instrument sounds between the groups. Prelingually deaf CI recipients rated themselves as significantly less able to follow a melody line and identify instrument styles compared to their postlingual peers. CONCLUSIONS: The results suggest that the pre- and postlingually deaf CI recipients demonstrate equivalent levels of music appreciation. This finding is of clinical importance, as CI clinicians should be actively encouraging all of their recipients to explore music listening as a part of their rehabilitation.

A multicentre clinical evaluation of paediatric cochlear implant users upgrading to the Nucleus(®) 6 system.

OBJECTIVES: The aim of this study was to investigate whether experienced paediatric cochlear implant users could show benefits to speech perception outcomes from the introduction of noise reduction and automated scene classification technologies as implemented in the Nucleus(®) 6 sound processor. Previous research with adult cochlear implant users had shown significant improvements in speech intelligibility for listening in noisy conditions and good user acceptance for upgrading to the Nucleus 6 processor. In adults, these improvements for listening in noise were primarily attributed to the use of a range of new input processing technologies including noise reduction, as well as introduction of automatic scene classification technology. METHODS: Experienced paediatric cochlear implant users (n=25) were recruited from four clinics located in three countries. Research participants were evaluated on three occasions, an initial session using their Nucleus 5 sound processor; a second session in which participants used the Nucleus 6 processor programmed with the same technologies as were used in their Nucleus 5 sound processor; and a final session in which participants used the Nucleus 6 processor programmed with the default technologies including automatic scene classification (SCAN) which automatically selects the microphone directionality, noise reduction (SNR-NR), and wind noise reduction (WNR) technologies. Prior to both the second and third evaluations, research participants had approximately two weeks take-home experience with the new system. Speech perception performances on monosyllabic word tests presented in quiet and in noise, and a sentence test presented in noise, were compared across the three processor conditions. Acceptance of the Nucleus 6 default settings was assessed in a final session. RESULTS: No group mean difference in performance was found for monosyllabic words in quiet. A significant improvement in speech perception was found for both monosyllabic words and sentences in noise with the default Nucleus 6 program condition as compared with the Nucleus 5 condition. No acceptance issues were noted for any of the children. CONCLUSIONS: Experienced paediatric cochlear implant users showed a significant improvement in speech perception in listening in noise when upgraded to the Nucleus 6 sound processor primarily due to the introduction of a noise reduction technology, and all children accepted the default program. These findings suggest that school-aged children may benefit from upgrading to the Nucleus 6 sound processor using the default program.

Evidence-based guidelines for recommending cochlear implantation for postlingually deafened adults.

OBJECTIVE: Adult selection criteria for cochlear implantation have been developed based on analysis of the post-operative performance of a large group of postlingually deafened adults. Original criteria published in 2004 were reviewed and amended to reflect outcomes currently being achieved by implant recipients. DESIGN: Retrospective review of 12-month post-operative speech perception performance of adults implanted at the Eye and Ear Hospital, Melbourne, Australia. STUDY SAMPLE: A total of 382 postlingually deafened adults, using a Freedom, Nucleus 5, or CI422 Slim Straight cochlear implant were used to create a comparative set of data. RESULTS: Revised guidelines suggest that adults with postlingual hearing loss can now be considered cochlear implant candidates if they obtain scores of up to 55% for open-set phonemes in quiet in the ear to be implanted. Functional benefit may vary depending on the recipients' contralateral hearing. CONCLUSIONS: This study supports the provision of cochlear implants to candidates with significant residual hearing when at least one ear meets the criterion outlined above. Patient-specific counseling is required to ensure the potential to benefit predicted by the current model is acceptable to the individual patient and their family. Counseling regarding functional benefit must take into consideration hearing in the contralateral ear.

Outcomes After Cochlear Implantation in the Very Elderly.

OBJECTIVE: To evaluate the outcomes after cochlear implantation (CI) in the elderly population, with a particular emphasis on perioperative complications, dizziness, and speech perception outcomes. STUDY DESIGN: A retrospective cohort study of elderly cochlear implant patients. SETTING: Tertiary referral center (Cochlear Implant Clinic, Royal Victorian Eye and Ear Hospital, Melbourne). PATIENTS: All patients aged 75 and above at the time of first cochlear implant (N = 150). Comparison was made between groups aged 85+ to 80-84, and 75-79. INTERVENTIONS: All patients received Nucleus devices (either CI512 or CI24RE(CA)). MAIN OUTCOME MEASURES: Speech recognition scores both pre- and postimplantation, symptomatic dizziness and effects upon independent living after surgery, and the incidence of perioperative medical and surgical complications. Complications were classified as major (intrinsic device failure, device migration, extracochlear insertion, meningitis, surgical site infection requiring reoperation, wound breakdown, permanent facial nerve paralysis) and minor (tinnitus, transient facial nerve palsy, facial nerve stimulation, taste disturbance, delayed wound healing). RESULTS: All three cohorts had poor preoperative speech perception. There was significant improvement in postoperative word scores at 3 and 12 months across all groups. There was no statistically significant difference between the three cohorts in terms of speech recognition outcomes at 3 and 12 months. After surgery, more than 20% of patients at all ages experienced transient imbalance, although the incidence did not differ significantly between age groups (p = 0.71). In total, there were 13 major complications in 7 patients (4.7%), and 28 minor complications in 25 patients (16.7%). CONCLUSION: Postoperative disequilibrium was commonly observed in this elderly population, yet patients still benefited with improved speech perception after cochlear implantation. Elderly patients can benefit from cochlear implantation, and age should not be a limitation for CI surgery. Cochlear implantation can be done safely and provides significant patient benefits.

Comprehensive analysis of cochlear implant failure: usefulness of clinical symptom-based algorithm combined with in situ integrity testing.

OBJECTIVE: Accurate diagnosis of cochlear implant failures is important for management; however, appropriate strategies to assess possible device failures are not always clear. The purpose of this study is to understand correlation between causes of device failure and the presenting clinical symptoms as well as results of in situ integrity testing and to propose effective strategies for diagnosis of device failure. STUDY DESIGN: Retrospective case review. SETTING: Cochlear implant center at a tertiary referral hospital. PATIENTS: Twenty-seven cases with suspected device failure of Cochlear Nucleus systems (excluding CI512 failures) on the basis of deterioration in auditory perception from January 2000 to September 2012 in the Melbourne cochlear implant clinic. MAIN OUTCOME MEASURES: Clinical presentations and types of abnormalities on in situ integrity testing were compared with modes of device failure detected by returned device analysis. RESULTS: Sudden deterioration in auditory perception was always observed in cases with "critical damage": either fracture of the integrated circuit or most or all of the electrode wires. Subacute or gradually progressive deterioration in auditory perception was significantly associated with a more limited number of broken electrode wires. Cochlear implant mediated auditory and nonauditory symptoms were significantly associated with an insulation problem. An algorithm based on the time course of deterioration in auditory perception and cochlear implant-mediated auditory and nonauditory symptoms was developed on the basis of these retrospective analyses, to help predict the mode of device failure. In situ integrity testing, which included close monitoring of device function in routine programming sessions as well as repeating the manufacturer's integrity test battery, was sensitive enough to detect malfunction in all suspected device failures, and each mode of device failure showed a characteristic abnormality on in situ integrity testing. CONCLUSION: Our clinical manifestation-based algorithm combined with in situ integrity testing may be useful for accurate diagnosis and appropriate management of device failure. Close monitoring of device function in routine programming sessions as well as repeating the manufacturer's integrity test battery is important if the initial in situ integrity testing is inconclusive because objective evidence of failure in the implanted device is essential to recommend explantation/reimplantation.