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IMPORTANCE The cost of bilateral cochlear implantation (BCI) is usually not reimbursed by insurance companies because of a lack of well-designed studies reporting the benefits of a second cochlear implant. OBJECTIVE To determine the benefits of simultaneous BCI compared with unilateral cochlear implantation (UCI) in adults with postlingual deafness. DESIGN, SETTING, AND PARTICIPANTS A multicenter randomized clinical trial was performed. The study took place in 5 Dutch tertiary referral centers: the University Medical Centers of Utrecht, Maastricht, Groningen, Leiden, and Nijmegen. Forty patients eligible for cochlear implantation met the study criteria and were included from January 12, 2010, through November 2, 2012. The main inclusion criteria were postlingual onset of hearing loss, age of 18 to 70 years, duration of hearing loss of less than 20 years, and a marginal hearing aid benefit. Two participants withdrew from the study before implantation. Nineteen participants were randomized to undergo UCI and 19 to undergo BCI. INTERVENTIONS The BCI group received 2 cochlear implants during 1 surgery. The UCI group received 1 cochlear implant. MAIN OUTCOMES AND MEASURES The primary outcome was the Utrecht Sentence Test with Adaptive Randomized Roving levels (speech in noise, both presented from straight ahead). Secondary outcomes were consonant-vowel-consonant words in silence, speech-intelligibility test with spatially separated sources (speech in noise from different directions), sound localization, and quality of hearing questionnaires. Before any data were collected, the hypothesis was that the BCI group would perform better on the objective and subjective tests that concerned speech intelligibility in noise and spatial hearing. RESULTS Thirty-eight patients were included in the study. Fifteen patients in the BCI group used hearing aids before implantation compared with 19 in the UCI group. Otherwise, there were no significant differences between the groups' baseline characteristics. At 1-year follow-up, there were no significant differences between groups on the Utrecht Sentence Test with Adaptive Randomized Roving levels (9.1 dB, UCI group; 8.2 dB, BCI group; P = .39) or the consonant-vowel-consonant test (median percentage correct score 85.0% in the UCI group and 86.8% in the BCI group; P = .21). The BCI group performed significantly better than the UCI group when noise came from different directions (median speech reception threshold in noise, 14.4 dB, BCI group; 5.6 dB, BCI group; P <.001). The BCI group was better able to localize sounds (median correct score of 50.0% at 60 degrees, UCI group; 96.7%, BCI group; P CONCLUSIONS AND RELEVANCE This randomized clinical trial demonstrates a significant benefit of simultaneous BCI above UCI in daily listening situations for adults with postlingual deafness

Assessing auditory nerve condition by tone decay in deaf subjects with a cochlear implant

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Electro-acoustic pitch matching experiments in patients with single-sided deafness and a cochlear implant : Is there a need for adjustment of the default frequency allocation tables?

Patients with single-sided deafness (SSD) and a cochlear implant (CI) can compare the pitch of stimulated electrodes and acoustic tones. A pitch mismatch may negatively bear on the fusion of the signals from the two ears, which may limit auditory performance. We aimed to explore this mismatch, correlate it to performance, and finally to discuss its possible clinical consequences. Ten patients with SSD and a CI (Cochlear Ltd.) compared the pitch of electrical and acoustic stimuli. Patients had to choose one of two acoustic stimuli, with the pitch closest to the pitch of the electrical stimulus at electrodes 3, 7, 11, 15, and 19. The difference between the two acoustic stimuli iteratively decreased from 2 octaves to 1/8 octave, resulting in a "pitch match" per electrode. Furthermore, we computed the insertion angle of the CI electrode array based on high-resolution computed-tomography scans. Subsequently, we created frequency-place maps. The difference between our pitch matches and two references (the spiral ganglion map and the default frequency allocation by Cochlear Ltd.) was defined as "mismatch". We observed large intra- and intersubject variability. Following the tonotopic organization of the cochlea, we observed that the pitch matches decreased with increasing insertion angle. The pitch-matched frequencies were on average 2.0 and 1.3 octaves lower than the spiral ganglion map and the default frequency allocation, respectively. There was no significant correlation between performance (consonant-vowel-consonant phoneme recognition score) and mismatch (R(2) = 0.06, P > 0.1). Given the methodological considerations, and the insignificant correlation between mismatch and performance, pitch matching results must not necessarily lead to a change in clinical fitting strategies

Electro-acoustic pitch matching experiments in patients with single-sided deafness and a cochlear implant : Is there a need for adjustment of the default frequency allocation tables?

Patients with single-sided deafness (SSD) and a cochlear implant (CI) can compare the pitch of stimulated electrodes and acoustic tones. A pitch mismatch may negatively bear on the fusion of the signals from the two ears, which may limit auditory performance. We aimed to explore this mismatch, correlate it to performance, and finally to discuss its possible clinical consequences. Ten patients with SSD and a CI (Cochlear Ltd.) compared the pitch of electrical and acoustic stimuli. Patients had to choose one of two acoustic stimuli, with the pitch closest to the pitch of the electrical stimulus at electrodes 3, 7, 11, 15, and 19. The difference between the two acoustic stimuli iteratively decreased from 2 octaves to 1/8 octave, resulting in a "pitch match" per electrode. Furthermore, we computed the insertion angle of the CI electrode array based on high-resolution computed-tomography scans. Subsequently, we created frequency-place maps. The difference between our pitch matches and two references (the spiral ganglion map and the default frequency allocation by Cochlear Ltd.) was defined as "mismatch". We observed large intra- and intersubject variability. Following the tonotopic organization of the cochlea, we observed that the pitch matches decreased with increasing insertion angle. The pitch-matched frequencies were on average 2.0 and 1.3 octaves lower than the spiral ganglion map and the default frequency allocation, respectively. There was no significant correlation between performance (consonant-vowel-consonant phoneme recognition score) and mismatch (R(2) = 0.06, P > 0.1). Given the methodological considerations, and the insignificant correlation between mismatch and performance, pitch matching results must not necessarily lead to a change in clinical fitting strategies

Altered Cortical Activity in Prelingually Deafened Cochlear Implant Users Following Long Periods of Auditory Deprivation

Auditory stimulation during childhood is critical for the development of the auditory cortex in humans and with that for hearing in adulthood. Age-related changes in morphology and peak latencies of the cortical auditory evoked potential (CAEP) have led to the use of this cortical response as a biomarker of auditory cortical maturation including studies of cortical development after deafness and subsequent cochlear implantation. To date, it is unknown whether prelingually deaf adults, with early onset deafness (before the age of 2 years) and who received a cochlear implant (CI) only during adulthood, would display absent or aberrant CAEP waveforms as predicted from CAEP studies in late implanted prelingually deaf children. In the current study, CAEP waveforms were recorded in response to electric stimuli in prelingually deaf adults, who received their CI after the age of 21 years. Waveform morphology and peak latencies were compared to the CAEP responses obtained in postlingually deaf adults, who became deaf after the age of 16. Unexpectedly, typical CAEP waveforms with adult-like P1-N1-P2 morphology could be recorded in the prelingually deaf adult CI users. On visual inspection, waveform morphology was comparable to the CAEP waveforms recorded in the postlingually deaf CI users. Interestingly, however, latencies of the N1 peak were significantly shorter and amplitudes were significantly larger in the prelingual group than in the postlingual group. The presence of the CAEP together with an early and large N1 peak might represent activation of the more innate and less complex components of the auditory cortex of the prelingually deaf CI user, whereas the CAEP in postlingually deaf CI users might reflect activation of the mature neural network still present in these patients. The CAEPs may therefore be helpful in the assessment of developmental state of the auditory cortex

Correlation between subjective and objective hearing tests after unilateral and bilateral cochlear implantation

Background: There are many methods for assessing hearing performance after cochlear implantation. Standard evaluations often encompass objective hearing tests only, while patients' subjective experiences gain importance in today's healthcare. The aim of the current study was to analyze the correlation between subjective (self-reported questionnaires) and objective (speech perception and localization) hearing test results in adult cochlear implant (CI) users. Secondary, the correlation between subjective and objective hearing tests was compared between bilateral and unilateral CI patients. Methods: Data for this study were prospectively collected as part of a multicentre randomized controlled trial. Thirty-eight postlingually deafened adult patients were randomly allocated to receive either unilateral (n = 19) or bilateral (n = 19) cochlear implantation. We used data gathered after one year of follow-up. We studied the correlation between objectively measured speech perception and localization skills on the one hand and related domains of the Speech, Spatial and Qualities of Hearing Scale (SSQ) and Nijmegen Cochlear Implant Questionnaire (NCIQ) on the other hand. We also compared these correlations between unilateral and bilateral CI users. Results: We found significant weak to moderate negative correlations between the subjective test results (speech domain of the SSQ and the advanced speech perception domain of the NCIQ) and the related objective speech perception in noise test results (r = -0.33 to -0.48). A significant moderate correlation was found between the subjective test results (spatial domain of the SSQ) and the related objective localization test results (r = 0.59). The correlations in the group of bilateral CI patients (r = -0.28 to -0.54) did not differ significantly from the correlations in the group of unilateral CI patients (r = 0.15 to -0.40). Conclusions: Current objective tests do not fully reflect subjective everyday listening situations. This study elucidates the importance and necessity of questionnaires in the evaluation of cochlear implantation. Therefore, it is advised to evaluate both objective and subjective tests in CI patients on a regular basis. Trial registration: This trial was registered on March 11, 2009 in the Dutch Trial Register. Trial registration number: NTR1722

Effectiveness of Earplugs in Preventing Recreational Noise-Induced Hearing Loss : A Randomized Clinical Trial

IMPORTANCE: The incidence of hearing loss has risen in past years. Attendance at music festivals and concerts may contribute to this increasing problem. OBJECTIVE: To assess the effectiveness of earplugs in preventing temporary hearing loss immediately following music exposure. DESIGN, SETTING, AND PARTICIPANTS: A randomized, single-blind clinical trial was conducted on September 5, 2015, at an outdoor music festival in Amsterdam, the Netherlands. Normal-hearing adult volunteers were recruited via social media. An exclusion criterion was the participants' intention to wear earplugs. Of the 86 volunteers assessed, 51 were included in the study. All analyses were performed on an intention-to-treat basis. INTERVENTIONS: Participants were randomly assigned to a group using earplugs or an unprotected group during a 4½-hour festival visit. MAIN OUTCOMES AND MEASURES: The primary study outcome was a temporary threshold shift (TTS) on the audiogram, primarily for frequencies at 3 and 4 kHz. Secondary study outcomes included distortion product otoacoustic emission (DPOAE) measurements and claims of tinnitus using a questionnaire and tinnitus matching experiments. RESULTS: Of 51 participants included, 25 were randomized to the earplug group and 26 to the unprotected group. Nine in each group (36% and 35%, respectively) were men, and the mean (SD) ages were 27.3 (5.6) years in the earplug group and 27.0 (6.2) years in the unprotected group. Baseline demographics were similar in both groups. The time-averaged, equivalent A-weighted sound pressure level experienced was 100 dBA during the festival. A TTS over frequencies at 3 and 4 kHz after exposure was seen in 4 of 50 ears (8%) in the earplug group compared with 22 of 52 ears (42%) in the unprotected group (P < .001). The relative risk for a TTS after exposure was 5.3 (95% CI, 2.0-14.3) for the unprotected group vs the earplug group. The number needed to treat with earplugs for preventing 1 TTS was 2.9. The DPOAE amplitudes decreased significantly more over the frequencies 2 to 8 kHz in the unprotected group: the mean (SD) decrease in magnitude was 0.6 (2.8) dB in the earplug group vs 2.2 (1.9) dB in the unprotected group (P = .04). Newly induced tinnitus following sound exposure occurred in 3 of the 25 participants (12%) in the earplug group vs 10 of 25 (40%) in the unprotected group (difference, 28%; 95% CI, 3.6%-49.0%; P = .02). CONCLUSIONS AND RELEVANCE: Earplug use is effective in preventing temporary hearing loss after loud music exposure. The present randomized clinical trial adds proof to the scarce evidence and knowledge on this topic, which is a growing global problem. TRIAL REGISTRATION: trialregister.nl Identifier: NTR5401