Véronique J. C. Kraaijenga

Stable benefits of bilateral over unilateral cochlear implantation after two years: A randomized controlled trial

To investigate hearing capabilities and self‐reported benefits of simultaneous bilateral cochlear implantation (BiCI) compared with unilateral cochlear implantation (UCI) after a 2‐year follow‐up and to evaluate the learning effect of cochlear implantees over time.

Factors that influence outcomes in cochlear implantation in adults, based on patient-related characteristics – a retrospective study

Outcomes in speech perception following cochlear implantation in adults vary widely. Many studies have been carried out to identify and quantify factors that influence outcomes. This study adds a new dimension to pre‐existing literature.

Development of a Squelch Effect in Adult Patients After Simultaneous Bilateral Cochlear Implantation

Objectives: To investigate whether a squelch effect occurs in the first 3 years after simultaneous bilateral cochlear implantation and to investigate whether this effect increases during follow-up. Study Design: Prospective study as part of a multicenter randomized controlled trial that compares simultaneous bilateral cochlear implantation to sequential and unilateral cochlear implantation. Setting: Tertiary referral center. Patients: Nineteen postlingually deafened adults. Intervention: Simultaneous bilateral cochlear implantation. Main Outcome Measure: The squelch effect, measured yearly with a speech-intelligibility-in-noise test with spatially separated sources. Bilateral results were compared to unilateral results in which the cochlear implant at the noise side was turned off. The squelch effect was investigated for the patients’ best performing ear and for the left and right ears separately. Results: In 13 individual patients, a squelch effect was present after 1 year. This number increased during follow-up years. On group level, a squelch effect was present in patients’ best performing ear after 2 and 3 years (1.9 dB). A squelch effect was present in both ears after 3 years (AS: 1.7 dB, AD: 1.3 dB). Conclusion: Patients who underwent simultaneous bilateral cochlear implantation developed a measurable benefit from the squelch effect after 2 years in their best performing ear and after 3 years in both ears. These observations suggest that the brain learns to use interaural differences to segregate sound from noise after simultaneous bilateral cochlear implantation. The squelch effect increased over time which suggests a growth in cortical integration and differentiation of inputs from bilateral CIs due to brain plasticity. Trial Registration: Dutch Trial Register NTR1722. Level of evidence: 1b.

The Effect of Earplugs in Preventing Hearing Loss From Recreational Noise Exposure: A Systematic Review

IMPORTANCE The prevalence of hearing loss among children and adolescents is rising dramatically, caused mainly by increased exposure to recreational noise. OBJECTIVE To present a systematic overview of the effectiveness of wearing earplugs to music venues, such as nightclubs and concert halls, to prevent hearing loss and tinnitus directly after exposure. EVIDENCE ACQUISITION PubMed, EMBASE, and the Cochrane Library databases were searched for articles from database inception to June 22, 2015, using the keywords music and earplugs and all synonyms. Titles, abstracts, and full text of retrieved articles were screened for eligible articles. The directness of evidence (relevance of the assessed articles) and risk of bias of eligible articles were assessed. For the included articles, the study characteristics and data on our outcomes of interest (hearing loss and tinnitus) were extracted. Data analysis occurred from June 22 to July 3, 2015. FINDINGS Of 228 articles screened, 4 were eligible for critical appraisal. After critical appraisal, 2 studies with a high directness of evidence and low or moderate risk of bias remained for data extraction. Only 1 of these articles was a randomized clinical trial, which found significantly lower postconcert differences in thresholds and a lower proportion of threshold shifts in the group using earplugs compared with the unprotected group. In the other study, only 3 individuals wore earplugs, and no significant differences were found between the 2 groups. CONCLUSIONS AND RELEVANCE The available evidence on the effectiveness of earplugs in preventing hearing damage directly after recreational music exposure is scarce. Only 1 well-conducted randomized clinical trial was found, which showed that wearing earplugs to concerts is effective in reducing postconcert threshold shifts. There is a need for further research on this topic to strengthen the level of evidence. Physicians should promote awareness on the risks of recreational noise and recommend the use of earplugs among their patients who visit music venues.

Agreement between health utility instruments in cochlear implantation

The objectives of our study were threefold: to compare health utility scores measured with different health utility instruments in adult patients with bilateral deafness, to compare the change in health utility scores after unilateral or bilateral cochlear implantation using the different health utility instruments and to assess which health utility instrument would be the most appropriate for future studies on cochlear implantation.

Objective and Subjective Measures of Simultaneous vs Sequential Bilateral Cochlear Implants in Adults: A Randomized Clinical Trial

Importance To date, no randomized clinical trial on the comparison between simultaneous and sequential bilateral cochlear implants (BiCIs) has been performed. Objective To investigate the hearing capabilities and the self-reported benefits of simultaneous BiCIs compared with those of sequential BiCIs. Design, Setting, and Participants A multicenter randomized clinical trial was conducted between January 12, 2010, and September 2, 2012, at 5 tertiary referral centers among 40 participants eligible for BiCIs. Main inclusion criteria were postlingual severe to profound hearing loss, age 18 to 70 years, and a maximum duration of 10 years without hearing aid use in both ears. Data analysis was conducted from May 24 to June 12, 2016. Interventions The simultaneous BiCI group received 2 cochlear implants during 1 surgical procedure. The sequential BiCI group received 2 cochlear implants with an interval of 2 years between implants. Main Outcomes and Measures First, the results 1 year after receiving simultaneous BiCIs were compared with the results 1 year after receiving sequential BiCIs. Second, the results of 3 years of follow-up for both groups were compared separately. The primary outcome measure was speech intelligibility in noise from straight ahead. Secondary outcome measures were speech intelligibility in noise from spatially separated sources, speech intelligibility in silence, localization capabilities, and self-reported benefits assessed with various hearing and quality of life questionnaires. Results Nineteen participants were randomized to receive simultaneous BiCIs (11 women and 8 men; median age, 52 years [interquartile range, 36-63 years]), and another 19 participants were randomized to undergo sequential BiCIs (8 women and 11 men; median age, 54 years [interquartile range, 43-64 years]). Three patients did not receive a second cochlear implant and were unavailable for follow-up. Comparable results were found 1 year after simultaneous or sequential BiCIs for speech intelligibility in noise from straight ahead (difference, 0.9 dB [95% CI, –3.1 to 4.4 dB]) and all secondary outcome measures except for localization with a 30° angle between loudspeakers (difference, –10% [95% CI, –20.1% to 0.0%]). In the sequential BiCI group, all participants performed significantly better after the BiCIs on speech intelligibility in noise from spatially separated sources and on all localization tests, which was consistent with most of the participants’ self-reported hearing capabilities. Speech intelligibility-in-noise results improved in the simultaneous BiCI group up to 3 years following the BiCIs. Conclusions and Relevance This study shows comparable objective and subjective hearing results 1 year after receiving simultaneous BiCIs and sequential BiCIs with an interval of 2 years between implants. It also shows a significant benefit of sequential BiCIs over a unilateral cochlear implant. Until 3 years after receiving simultaneous BiCIs, speech intelligibility in noise significantly improved compared with previous years. Trial Registration trialregister.nl Identifier: NTR1722

Towards Clinical Application of Neurotrophic Factors to the Auditory Nerve; Assessment of Safety and Efficacy by a Systematic Review of Neurotrophic Treatments in Humans

Animal studies have evidenced protection of the auditory nerve by exogenous neurotrophic factors. In order to assess clinical applicability of neurotrophic treatment of the auditory nerve, the safety and efficacy of neurotrophic therapies in various human disorders were systematically reviewed. Outcomes of our literature search included disorder, neurotrophic factor, administration route, therapeutic outcome, and adverse event. From 2103 articles retrieved, 20 randomized controlled trials including 3974 patients were selected. Amyotrophic lateral sclerosis (53%) was the most frequently reported indication for neurotrophic therapy followed by diabetic polyneuropathy (28%). Ciliary neurotrophic factor (50%), nerve growth factor (24%) and insulin-like growth factor (21%) were most often used. Injection site reaction was a frequently occurring adverse event (61%) followed by asthenia (24%) and gastrointestinal disturbances (20%). Eighteen out of 20 trials deemed neurotrophic therapy to be safe, and six out of 17 studies concluded the neurotrophic therapy to be effective. Positive outcomes were generally small or contradicted by other studies. Most non-neurodegenerative diseases treated by targeted deliveries of neurotrophic factors were considered safe and effective. Hence, since local delivery to the cochlea is feasible, translation from animal studies to human trials in treating auditory nerve degeneration seems promising.

The effect of side of implantation on unilateral cochlear implant performance in patients with prelingual and postlingual sensorineural hearing loss: A systematic review

Cerebral lateralisation of language processing leads to a right ear advantage in normal hearing subjects. The aim of this study was to present a systematic overview of the effect of implantation side on postoperative cochlear implant performance in patients with symmetrical severe to profound sensorineural hearing loss.

Association of Behavior With Noise-Induced Hearing Loss Among Attendees of an Outdoor Music Festival: A Secondary Analysis of a Randomized Clinical Trial

Importance To date, factors associated with noise-induced hearing loss at music festivals have not yet been analyzed in a single comprehensive data set. In addition, little is known about the hearing loss–associated behavior of music festival attendees. Objectives To assess which factors are associated with the occurrence of a temporary threshold shift (TTS) after music exposure and to investigate the behavior of music festival attendees. Design, Setting, and Participants This prospective post hoc analysis gathered data from a randomized, single-blind clinical trial conducted on September 5, 2015, at an outdoor music festival in Amsterdam, the Netherlands. Adult volunteers with normal hearing were recruited via social media from August 26 through September 3, 2015. Intention to use earplugs was an exclusion criterion. Of 86 volunteers assessed, 51 were included. This post hoc analysis was performed from October 3, 2016, through February 27, 2017. Interventions Music festival visit for 4.5 hours. Main Outcomes and Measures The primary outcome was a TTS on a standard audiogram for the frequencies 3.0- and 4.0-kHz. Multivariable linear regression was performed to determine which factors are associated with a TTS. A questionnaire on behavior, hearing, and tinnitus was distributed to the participants before and after the festival visit. Results A total of 51 participants were included (18 men [35%] and 33 women [65%]) with a mean (SD) age of 27 (6) years. Mean (SD) threshold change across 3.0 and 4.0 kHz was 5.4 (5.7) dB for the right ear and 4.0 (6.1) dB for the left ear. Earplug use (absolute difference in the left ear, −6.0 dB [95% CI, −8.7 to −3.2 dB]; in the right ear, −6.4 dB [95% CI, −8.8 to −4.1 dB]), quantity of alcohol use (absolute difference per unit in the left ear, 1.1 dB [95% CI, 0.5 to 1.7 dB]; in the right ear, 0.7 dB [95% CI, 0.1 to 1.4 dB]), drug use (absolute difference in the right ear, 6.0 dB [95% CI, 0.9 to 11.1 dB]), and male sex (absolute difference in the right ear, 4.1 dB [95% CI, 0.3 to 5.9 dB]) were independently associated with hearing loss, with earplug use being the most important factor. Unprotected participants reported significantly worse subjective hearing performance and tinnitus after the festival visit than did participants using earplugs (Cramer V, 0.62 [95% CI, 0.47-0.79] and 0.39 [95% CI, 0.16-0.62], respectively). In the earplug group, the perceived loudness (r = −0.72; 95% CI, −1.00 to −0.43) and appreciation (r = 0.53; 95% CI, 0.29 to 0.78) of music and speech perception (r = 0.21; 95% CI, 0.09 to 0.35) were correlated with the duration of earplug use. Conclusions and Relevance The present study identified nonuse of earplugs, use of alcohol and drugs, and male sex as associated with a TTS at an outdoor music festival. Physicians should consider these factors to raise awareness about the combined risk of attending music festivals without using earplugs while consuming alcohol and/or drugs. The intention to use earplugs was correlated with the loudness and appreciation of music with earplugs, which may advocate for the use of personalized earplugs. Trial Registration trialregister.nl Identifier: NTR5401

Tinnitus after Simultaneous and Sequential Bilateral Cochlear Implantation

Importance There is an ongoing global discussion on whether or not bilateral cochlear implantation should be standard care for bilateral deafness. Contrary to unilateral cochlear implantation, however, little is known about the effect of bilateral cochlear implantation on tinnitus. Objective To investigate tinnitus outcomes 1 year after bilateral cochlear implantation. Secondarily, to compare tinnitus outcomes between simultaneous and sequential bilateral cochlear implantation and to investigate long-term follow-up (3 years). Study design This study is a secondary analysis as part of a multicenter randomized controlled trial. Methods Thirty-eight postlingually deafened adults were included in the original trial, in which the presence of tinnitus was not an inclusion criterion. All participants received cochlear implants (CIs) because of profound hearing loss. Nineteen participants received bilateral CIs simultaneously and 19 participants received bilateral CIs sequentially with an inter-implant interval of 2 years. The prevalence and severity of tinnitus before and after simultaneous and sequential bilateral cochlear implantation were measured preoperatively and each year after implantation with the Tinnitus Handicap Inventory (THI) and Tinnitus Questionnaire (TQ). Results The prevalence of preoperative tinnitus was 42% (16/38). One year after bilateral implantation, there was a median difference of −8 (inter-quartile range (IQR): −28 to 4) in THI score and −9 (IQR: −17 to −9) in TQ score in the participants with preoperative tinnitus. Induction of tinnitus occurred in five participants, all in the simultaneous group, in the year after bilateral implantation. Although the preoperative and also the postoperative median THI and TQ scores were higher in the simultaneous group, the median difference scores were equal in both groups. In the simultaneous group, tinnitus scores fluctuated in the 3 years after implantation. In the sequential group, four patients had an additional benefit of the second CI: a total suppression of tinnitus compared with their unilateral situation. Conclusion While bilateral cochlear implantation can have a positive effect on preoperative tinnitus complaints, the induction of (temporary or permanent) tinnitus was also reported. Clinical Trial Registration Dutch Trial Register NTR1722.