Is mastoidectomy indispensable in cochlear implant surgery?

OBJECTIVE: To challenge the need for mastoidectomy in cochlear implant (CI) surgery by comparing the advantages and disadvantages of the classic technique for CI, the mastoidectomy posterior tympanotomy approach (MPTA), with the suprameatal approach (SMA), a nonmastoidectomy approach. STUDY DESIGN and SETTING: A retrospective study of 290 patients who underwent cochlear implantation in our department between 1989 and 2002. One hundred fifty-seven of them underwent the MPTA and 133 underwent the SMA. The ability of the electrode to expand in the MPTA patients who were reoperated on was examined, as was the influence of mastoidectomy on the course of chronic secretory otitis media (SOM) in a group of 56 children who suffered from chronic SOM prior to implantation. RESULTS: In all 4 reoperated children, in whom the MPTA was used, the mastoid was completely closed by bony regrowth on the cortical portion of the mastoid and the mastoid cavity was obliterated. The electrode had been embedded in dense fibrous tissue and bony spicule, preventing electrode expansion. Mastoidectomy was found to have no influence on the course of chronic SOM. The rate of postoperative SOM was found to be equal in 40 children who were operated on using the MPTA compared with 16 operated on using the SMA. CONCLUSION: Using a nonmastoidectomy approach, such as the SMA, provides a wide exposure of the middle ear and promontory and thus enables a well-controlled cochleostomy site and safe insertion of the electrode into the cochlea. Mastoidectomy in CI surgery is not indispensable; it may cause more disadvantages than advantages.     

How does a cochlear implant speech processor work?

Cochlear implants have become a standard treatment modality for sensorineural hearing loss. In this review article, assembly and function of a cochlear implant are described. Cochlear implants replace the normal inner ear by transforming acoustic sound signals into electric stimuli and deliver these to the auditory nerve. Speech processors translate the acoustic signal of the microphone into one that fits electrostimulation of the auditory system. In multiple steps, the signal has to be analyzed and processed to fit the demands of electrical stimulation. The speech processor then sends commands and the energy for stimulation to the implanted parts via a transcutaneous high frequency radio link. The implant refers the information as electrical stimuli to each electrode contact.     

Is there a best side for cochlear implants in post-lingual patients?

Introduction

Cochlear Implant is a sensory prosthesis capable of restoring hearing in patients with severe or profound bilateral sensorineural hearing loss.

Evaluation of pediatric cochlear implant care throughout Europe: Is European pediatric cochlear implant care performed according to guidelines?

Objectives: International guidelines indicate that children with profound hearing loss should receive a cochlear implant (CI) soon after diagnosis in order to optimize speech and language rehabilitation. Although prompt rehabilitation is encouraged by current guidelines, delays in cochlear implantation are still present. This study investigated whether European countries establish timely pediatric CI care based on epidemiological, commercial, and clinical data.

Methods: An estimation of the number of pediatric CI candidates in European countries was performed and compared to epidemiological (Euro-CIU), commercial (Cochlear^®), and clinical (institutional) age-at-implantation data. The ages at implantation of pediatric patients in eight countries (the Netherlands, Belgium, Germany, the United Kingdom, France, Turkey, Portugal, and Italy) between 2005 and 2015 were evaluated.

Results: From 2010 onwards, over 30% of the pediatric CI candidates were implanted before 24 months of age. Northern European institutions implanted children on average around 12 months of age, whereas southern European institutions implanted children after 18 months of age. The Netherlands and Germany implanted earliest (between 6 and 11 months).

Discussion: Implemented newborn hearing screening programs and reimbursement rates of CIs vary greatly within Europe due to local, social, financial, and political differences. However, internationally accepted recommendations are applicable to this heterogeneous European CI practice. Although consensus on early pediatric cochlear implantation exists, this study identified marked delays in European care.

Conclusion: Regardless of the great heterogeneity in European practice, reasons for latency should be identified on a national level and possibilities to prevent avoidable future implantation delays should be explored to provide national recommendations.     

Which imaging modality in cochlear implant candidates?

European Archives of Oto-Rhino-Laryngology - There is no guideline or consensus on preoperative radiologic imaging modality despite the fact that it has a vital importance in appropriate candidacy...     

Can the acoustic change complex be recorded in an individual with a cochlear implant? Separating neural responses from cochlear implant artifact

The purpose of this case study was to determine whether the P1-N1-P2 acoustic change complex (ACC) could be recorded in an individual with a cochlear implant. In a cochlear implant recipient, stimulus-related artifact from the implant can overlap the evoked potential of interest, making it difficult to determine whether the recorded response is neural or a simple reflection of the artifact. This is an even greater technical challenge for the ACC because stimuli having relatively long durations are used. The subject was a 24-year-old with a diagnosis of auditory neuropathy/auditory dys-synchrony and used a MED-EL Tempo+ cochlear implant in her left ear. The ACC was recorded to synthetic vowels containing a change of F2 at midpoint ranging from 0 (no change) to 1200 Hz (perceived as /ui/). The stimuli were presented randomly at 75 dB SPL via a loudspeaker. In one condition the subject ignored the stimuli and watched a captioned video. In the other, the subject pressed one button on a response pad if she perceived an acoustic change at stimulus midpoint and another if she did not. Cortical auditory evoked potentials were recorded from 32 scalp electrodes. Results indicated that the ACC was present and could be teased apart from the cochlear implant stimulus artifact. ACC thresholds showed good agreement with behavioral discrimination performance, and therefore, results are positive for the potential clinical application of the ACC technique to individuals with cochlear implants.     

Is psychological status a determinant of speech perception outcomes in highly selected good adolescent cochlear implant users?

OBJECTIVE: The main purpose of this study was to assess the relationship between the speech perception skills and state-trait anxiety in cochlear implant user adolescents who were highly selected good candidates. The impact of preoperative speech perception ability on postoperative speech perception and state-trait anxiety status were also examined. SUBJECTS AND METHODS: The subjects for this study were 25 consecutively chosen congenitally profoundly deaf adolescents (12 boys, 13 girls) who received nucleus multi channel cochlear implants and were followed for at least a year at Hacettepe University. Daily Sentences in Turkish and State-Trait Anxiety Inventories (STAI) were administered to subjects after 12-72 months (mean: 35.28+/-18.27) of implant use. RESULTS: The trait and state anxiety scores were matched with the relative rank of normal hearing subjects' trait-state anxiety scores and the analysis of post-implant state-trait anxiety findings shows that both state and trait anxiety scores were widespread but still in normal range. The correlation between trait, state anxiety scores and speech perception ability was not statistically significant in adolescent cochlear implant users. However, their preoperative speech perception scores were significantly correlated with their postoperative speech perception abilities. CONCLUSION: The majority of adolescents, in this study, achieved varying degrees of open-set speech recognition and made greater gains than their previous auditory experience with hearing aids. Also, the indirect positive effects of early identification-amplification, communication therapy and counseling programs on their personal well-being is clearly observed from the outcomes of their state and trait anxiety scores. As a result of correlating the trait and state anxiety levels with pre- and post-implant speech perception skills, a significant negative correlation was expected. However, no statistical correlation was found between speech perception skills and the psychological outcomes. This result may be the indicator of the positive effect of the early habilitation-parental support and cochlear implant on the quality of life as the adolescents involved in this study were developmentally and audiologically ready for implantation. The present study provides understanding of the audiological and social-emotional influences of early identification and habilitation programs on adolescents with cochlear implants.     

Are cochlear implant patients suffering from perceptual dissonance?

Cochlear implants provide functional hearing to the majority of recipients and have gained widespread acceptance clinically, but the range of performance remains great and largely unexplained. Designs for implanted electrodes and electronics have converged, whereas novel speech processing strategies have proliferated. For each patient, the fitting audiologist must sort empirically through options that produce large but idiosyncratic differences in both objective performance and subjective preference. This review and analysis suggests that the place-pitch and rate-pitch theories on which cochlear implants have been designed are incomplete. The missing component may be related to the phase-locking of auditory nerve activity to both acoustic and electrical stimulation. This component is likely to be highly distorted by electrical stimulation but its importance as one of several different pitch encoding mechanisms may vary widely among patients. Systematic means to control these putative phase effects using modern, high-speed, and high-density cochlear implants may make it possible to identify more efficiently the best strategy for a given patient and to minimize the perceptual confusion that arises from conflicting cues.     

Does acoustic fundamental frequency information enhance cochlear implant performance?

Abstract

Objectives

Low-frequency information via an acoustic aid has been shown to increase speech intelligibility in noise for cochlear implant (CI) listeners. It has been suggested that fundamental frequency (F0) provides this advantage. This study aimed to investigate the contribution of F0.

Methods

Seven cochlear implant users having residual hearing at 125, 250, and 500 Hz contralateral to the implant were recruited. Speech intelligibility in noise was measured using an adaptive procedure for three listening conditions: (1) CI alone, (2) CI plus filtered acoustic information contralaterally, and (3) CI plus acoustic F0 contralaterally. In condition 2, the sentence material was low-passed at 500 Hz and presented via an insert earphone into the contralateral ear. In condition 3, F0 was extracted using Praat and presented as a sine wave with the same F0 variation over time as the original sentence.

Results

Although benefit was observed when low-frequency information was added for the majority of participants, on average no statistically significant difference was found for the three listening conditions.

Discussion

These results are not consistent with current literature. It is proposed that glimpsing cues may be responsible for the advantage observed in previous studies; in this study, both target and masker were presented in the acoustic condition and this may explain the discrepancy.

Conclusion

The benefit of additional acoustic information may be highly variable and individual to participants, but on average no statistically significant difference was seen.     

Does size of the cochlear nerve affect postoperative auditory performance in pediatric cochlear implant patients with normal cochlear nerves?

IntroductionCochlear implantation is an effective treatment method for severe to profound hearing loss. Many factors that may influence cochlear implantation success have been explained in previous studies. Apart from those, minor differences in size of normal cochlear nerves may affect postoperative performance.ObjectiveTo investigate whether the minor differences in cochlear nerve size in normal cochlear nerves affect postoperative cochlear implant performance.Methods30 pediatric prelingually deaf patients who were treated with cochlear implantation were included in this study. From the reconstructed parasagittal magnetic resonance images, the diameter and cross-sectional area of the cochlear nerve on the ipsilateral and contralateral side were measured. Auditory evaluations were performed 1, 3, 6 and 12 months following the first fitting. All the analysis was performed by using EARS®, evaluation of auditory responses to speech tool. Correlation between cochlear nerve diameter, cross-sectional area and postoperative auditory perception was analyzed to determine whether variation in cochlear nerve size contributes to postoperative auditory performance.ResultsThe mean diameter of the cochlear nerve on the ipsilateral side was 718.4 μm (504.5 ? 904.3 μm) and mean cross sectional area was 0.015 cm² (0.012 ? 0.018 cm²). On the contralateral side the mean cochlear nerve diameter was 714.4 μm (502.6 ? 951.4 μm) and mean cross sectional area was 0.014 cm² (0.011 ? 0.019 cm²). The correlation between the diameter and cross-sectional area of the ipsilateral and contralateral cochlear nerve revealed no significance. Mean score at first month monosyllable-trochee-polysyllable test, MTP1, was 0.17 (0.08 ? 0.33), at 6th month with 6 words test, 6th month MTP6 was 0.72 (0.39 ? 1.0), at 6th month with 12 words, 6th month MTP 12 was 0.46 (0.17 ? 0.75) and at 12th month with 12 words, 12th month MTP12 was 0.73 (0.25 ? 1.0). There was no correlation between the monosyllable-trochee-polysyllable test, values at any time with the diameter of the ipsilateral cochlear nerve. However, the first month MTP, 6th month MTP6 and 12th month MTP12 correlated with the cross-sectional area of the ipsilateral cochlear nerve.ConclusionMeasuring the cross sectional area of the normal- appearing cochlear nerve may give important prognostic knowledge on cochlear implant outcomes. In patients with a larger cross sectional area the auditory performance was better and faster. Although normal appearing, slight differences on cross sectional area of the cochlear nerve may affect performance. Measuring the size of the cochlear nerve on parasagittal magnetic resonance images may provide beneficial information on the postoperative rehabilitation process.     

Should a hearing aid in the contralateral ear be recommended for children with a unilateral cochlear implant?

OBJECTIVES: To predict bimodal benefit before cochlear implantation, we compared the performances of participants with bimodal fitting and with a cochlear implant alone on speech perception tests. METHODS: Twenty-two children with a cochlear implant in one ear and a hearing aid in the other (bimodal fitting) were included. Several aided and unaided average hearing thresholds and the aided word recognition score of the hearing aid ear were related to the bimodal benefit on a phoneme recognition test in quiet and in noise. Results with bimodal fitting were compared to results with the cochlear implant alone on a phoneme recognition test in quiet and in noise. RESULTS: No relationship was found between any of the hearing thresholds or the aided phoneme recognition score of the hearing aid ear and the bimodal benefit on the phoneme recognition tests. At the group level, the bimodal scores on the phoneme recognition tests in quiet and in noise were significantly better than the scores with the cochlear implant alone. CONCLUSIONS: Preoperatively available audiometric parameters are not reliable predictors of bimodal benefit in candidates for cochlear implantation. Children with unilateral implants benefit from bimodal fitting on speech tests. This improvement in performance warrants the recommendation of bimodal fitting even when bimodal benefit cannot be predicted.     

Telephone use: What benefit do cochlear implant users receive?

This study evaluated the use of landline and mobile phones in an international sample of cochlear implant users. A custom-designed survey was mailed to cochlear implant users from four different countries. A link to the survey was posted on the MED-EL website, with responses from a further six countries. Results from 196 surveys show that there is a significant shift from pre-operative non-use of a telephone to use of a telephone post-operatively. Seventy-one percent of MED-EL cochlear implant users are able to use a landline telephone to some extent and 54% are able to use a mobile phone to some extent. Talking to familiar speakers about familiar topics is the easiest listening condition on the telephone, and it is easier to recognize a voice using the landline. Many respondents found it difficult to make a call without some assistance. Most respondents could manage to call someone in an emergency, even on a mobile phone. Data obtained should provide useful information in the counselling and rehabilitation of cochlear implant recipients and candidates.     

Telephone use: what benefit do cochlear implant users receive?

This study evaluated the use of landline and mobile phones in an international sample of cochlear implant users. A custom-designed survey was mailed to cochlear implant users from four different countries. A link to the survey was posted on the MED-EL website, with responses from a further six countries. Results from 196 surveys show that there is a significant shift from pre-operative non-use of a telephone to use of a telephone post-operatively. Seventy-one percent of MED-EL cochlear implant users are able to use a landline telephone to some extent and 54% are able to use a mobile phone to some extent. Talking to familiar speakers about familiar topics is the easiest listening condition on the telephone, and it is easier to recognize a voice using the landline. Many respondents found it difficult to make a call without some assistance. Most respondents could manage to call someone in an emergency, even on a mobile phone. Data obtained should provide useful information in the counselling and rehabilitation of cochlear implant recipients and candidates.     

Inside implant criteria or not? – Detection of non-organic hearing loss during cochlear implant assessment

Objectives: The diagnosis of non-organic hearing loss (NOHL) is a difficult but important issue during the assessment process for cochlear implantation (CI). We aim to identify the key factors in identifying patients with NOHL during CI assessment and present our local screening protocol for NOHL.

Methods: A retrospective review of patients referred to the Yorkshire Auditory Implant Service (YAIS) between 2003 and 2015 who were subsequently diagnosed with NOHL during the assessment. Patient demographic data, audiological and functional assessments were assessed.

Results: Thirty-two patients were included in the study. Mean age was 43 years (range 14–82 years). Male to female ratio was 1:1.7. Indicators of possible NOHL included a sudden deterioration in hearing (n?=?21; 66%), mismatches in observed behaviour and either pure-tone audiogram (PTA) (n?=?27; 84%) or functional testing (n?=?20; 80%) and stapedial reflexes below reported audiological thresholds (n?=?12; 46%). A mismatch in functional hearing and PTA was seen in 72% of patients. Patients with suspected NOHL were referred for further objective testing. All 23 patients who underwent objective testing had better hearing levels compared to reported hearing thresholds thus placing them outside of implant criteria. Five candidates were found to have normal hearing thresholds.

Discussion: NOHL can present a significant challenge to the implant team, particularly in the subgroup with a pre-existing organic hearing loss with non-organic overlay. We discuss the common features in this cohort of patients.

Conclusions: To facilitate the identification of patients with NOHL, the YAIS has developed a screening protocol.