Cochlear implantees: Analysis of behavioral and objective measures for a clinical population of various age groups.

INTRODUCTION: As of 2014 more than 1200 patients have received a cochlear implant (CI) at Oslo University Hospital (OUS) and approximately half of them have been children. The data obtained from these patients have been used to develop a comprehensive database for a systematic analysis of several objective measurements and programming measurements. During the past 10 years, we have used an objective measurements protocol for our CI surgeries. Our intra-operative protocol includes: Evoked Compound Action Potentials (ECAP), visually observed Electrically evoked Stapedius Reflex Threshold (ESRT), and electrode impedances. Post-operative (Post-OP) programming sessions typically begin 4-6 weeks after surgery and continue on a scheduled basis. The initial programming data include threshold levels (T-levels) and comfortable levels (C-levels) for the different patient age groups. In this study, we compared initial stimulation levels and stimulation levels after at least 1 year of CI with objective measurements obtained intra-operatively. METHOD: This study focused on the development of a comprehensive database of detailed intra-operative objective measures and post-OP programming measurements from a group of 296 CI patients who received the same type of CI and electrode configuration (Cochlear Corporation CI with Contour electrode). This group included 92 bilateral CI patients. Measurements from 388 CI devices were studied. Patients were divided into 5 different age groups at the age of implantation: 0-2, 2-5, 5-10, 10-20, and above 20 years in order to investigate age-related differences in programming levels and objective measurements. For the comparison analysis we used T- and C-levels obtained after the last day of initial programming and also after at least 1 year implant use. These programming levels were then correlated with some of the intra-operative objective measurements. RESULTS: T-levels were found to be the lowest for the youngest patient group and increased with age. C-levels varied within age groups and frequency range. Patients above 20 years of age had the highest comfort levels in the low to mid-frequencies (electrodes 22-8) and the lowest comfort levels in the high-frequency range (electrodes 1-7). Correlation coefficients between intra-operative objective measurements and programming levels were found to be in the range of no correlation to moderate correlation. Adult patients had the most significant correlation coefficients between ECAP thresholds and T-levels in the low frequencies. The younger patients aged 10-20 years and 5-10 years had more significant correlations in the higher frequency channels compared to the other age groups. Intra-operative visually observed ESRTs and electrode impedances were not significantly correlated with initial or stable programming levels for the children or adults. CONCLUSION: Analyzing initial and follow-up mapping levels from previous patients is very important for a CI Center in terms of quality control. The mean T/C-levels reported in this study can provide guidance to our programming audiologists and help them determine the initial programming levels to be stored in the speech processor, especially for very young patients. Unfortunately intra-operative objective measures in our study, such as ECAP, ESRT, and electrode impedances did not provide statistically significant correlations that may help to predict the programming T- and C-levels for all patients. However, we have observed cases where the intra-operative objective measures of ESRT and TECAP profiles were very similar to an individual's MAP profile. It was not possible, however, to determine why some patients did not have an objective measures profile that was similar to their programming levels profile.

Resolution of untoward nonauditory stimulation and cochlear implant performance gain after extraction of a stainless steel dental crown in a patient with cochlear otosclerosis.

OBJECTIVE: To report a unique case of untoward nonauditory stimulation and cochlear implant performance deterioration after the placement of a stainless steel dental crown. STUDY DESIGN: Clinical capsule report. SETTING: Tertiary academic referral center. PATIENT: A 64-year-old female with a history of advanced otosclerosis and sequential bilateral cochlear implantation was evaluated at our institution for concerns of poor device performance. Approximately 3 years earlier, the patient had undergone stainless steel mandibular molar crown placement. After her dental procedure, she began experiencing worsening facial nerve stimulation, pain, and poor performance with the implant in her right ear. In-house device integrity testing demonstrated a series of phase reversals in the electrode voltages involving the mid-portion of the array that were consistent with otosclerosis and current shunting. RESULTS: The patient underwent removal of the mandibular crown 5 years after initial placement and experienced diminished facial nerve stimulation, resolution of pain, and a statistically significant improvement in monosyllabic word scores and speech in noise testing (Consonant-Nucleus-Consonant, 36%-76%; Bamford-Kowal-Bench Speech-in-Noise, 15-10.5 dB SNR). These findings were reproducible with serial audiometric testing over the subsequent 1.5 years, and she subjectively reported a substantial and lasting improvement in sound quality. CONCLUSION: We present the first published report documenting resolution of nonauditory stimulation and objective device performance improvement after stainless steel crown extraction. Although we cannot make any definitive conclusions based on a single report, it remains plausible that dental work incorporating metal substrates may interfere with device function through participation in aberrant current shunting in patients with otosclerosis.

Superficial siderosis of the central nervous system: phenotype and implications for audiology and otology.

OBJECTIVE: Superficial siderosis of the central nervous system (SSCN) results after chronic subarachnoid hemorrhage. Consequent demyelination, particularly of the cochleovestibular nerve and cerebellum, causes auditory-vestibular dysfunction. Predominant symptoms include progressive sensorineural hearing loss, imbalance, and ataxia. Despite characteristic auditory-vestibular involvement, SSCN is not well known among the hearing health community. STUDY DESIGN: Clinical records of 49 patients diagnosed with SSCN were reviewed. Analysis included review of demographic, audiometric, and vestibular data of the largest sample to date and comparison to 31 audiovestibular case reports in the literature. RESULTS: Hearing loss and disordered balance were reported by 92% and 67% of patients, respectively. Results suggest variable but substantial auditory-vestibular involvement related to SSCN. Hearing loss is typically progressive, sloping, and asymmetric and exceeds hearing loss expected based on age or sex. Decreased word recognition is possible and traditional amplification may fail to provide benefit. CONCLUSION: SSCN is a destructive disorder affecting the auditory-vestibular system. Although not a common diagnosis, SSCN may be more prevalent than clinicians realize. Site of lesion may be anywhere within the auditory-vestibular system from the inner ear to the cortex, although the cochleovestibular nerve and cerebellum are particularly vulnerable. The progressive retrocochlear nature of the disorder makes differential diagnosis difficult and development of effective treatment options challenging. It is essential that audiologists and otologists recognize this uncommon cause of sensorineural hearing loss and balance disorder and the implications for evaluation, treatment, and counseling.

Multi-site diagnosis and management of 260 patients with auditory neuropathy/dys-synchrony (auditory neuropathy spectrum disorder).

Test results and management data are summarized for 260 patients with diagnoses of Auditory Neuropathy Spectrum Disorder (ANSD). Hearing aids were tried in 85 of these patients, and 49 patients tried cochlear implants. Approximately 15% reported some benefit from hearing aids for language learning, while improvement in speech comprehension and language acquisition was reported in 85% of patients who were implanted. Approximately 5% (13/260) of the total population developed normal speech and language without intervention. Patients were diagnosed at our laboratory (n=66) or referred from other sites (n=194), and all showed absent/grossly abnormal auditory brainstem responses (ABR), often 'ringing' cochlear microphonics, and the presence or history of otoacoustic emissions. Etiologies and co-existing conditions included genetic (n=41), peripheral neuropathies (n=20), perinatal jaundice and/or anoxia and/or prematurity (n=74). These patients comprise 10% or more of hearing impaired patients; their language acquisition trajectories are generally unpredictable from their audiograms.

Evidence for the expansion of adult cochlear implant candidacy.

OBJECTIVES: The primary objective of this study was to determine whether a revision and/or expansion of current audiologic cochlear implant candidacy criteria is warranted. DESIGN: The study design was a retrospective review of postoperative speech perception performance for 22 adult cochlear implant recipients who demonstrated preoperative Consonant Nucleus Consonant word recognition scores of 30% or higher in the best-aided condition. This criterion was chosen to exceed that specified by the North American clinical trial of the Nucleus Freedom cochlear implant system. RESULTS: The mean preoperative best-aided monosyllabic word score for the 22 patients was 41% correct. The degree of postoperative benefit for the best postoperative condition (electric only or bimodal) ranged from 10 to 68 percentage points with a mean benefit of 27 percentage points for the electric-only condition and 40 percentage points for the bimodal condition. Statistical analyses revealed highly significant differences between preoperative-aided, implant-only, and bimodal performance on Consonant Nucleus Consonant monosyllabic word recognition performance. That is, both postoperative scores--electric only and bimodal--were significantly different from one another and from the preoperative best-aided performance. CONCLUSIONS: The current results suggest that a large-scale reassessment of manufacturer and Medicare preoperative audiologic candidacy criteria for adults is warranted to allow more hearing-impaired individuals to take advantage of the benefits offered by cochlear implantation.

Cochlear implant patients with superficial siderosis.

BACKGROUND: Considered a rare disorder, superficial siderosis of the central nervous system (SSCN) has become more frequently diagnosed in recent years. As it is characterized by progressive sensorineural hearing loss, patients' needs may surpass the capability of hearing aid technology. Despite the retrocochlear nature of the disorder, patients have undergone cochlear implantation (CI) with varying success. PURPOSE: To summarize the issues surrounding cochlear implant candidates with SSCN as well as highlight trends in performance postimplantation. RESEARCH DESIGN: Retrospective case reports of seven cochlear implant candidates detail the symptoms, typical audiologic presentation, and array of clinical issues for patients with this progressive and potentially fatal disease. RESULTS: Despite the retrocochlear component of a hearing loss caused by SSCN, cochlear implantation may be a viable option. CONCLUSIONS: It is essential that the CI audiologist not only be aware of the disorder but also be well versed in the resulting implications for the cochlear implant process. A more thorough case history, an expanded candidacy test battery, and knowledge of the typical presentation of SSCN are critical. The diagnosis of SSCN will impact expectations for success with the cochlear implant, and counseling should be adjusted accordingly.

Word recognition following implantation of conventional and 10-mm hybrid electrodes.

We compared the effectiveness of 2 surgical interventions for improving word recognition ability in a quiet environment among patients who presented with: (1) bilateral, precipitously sloping, high-frequency hearing loss; (2) relatively good auditory thresholds at and below 500 Hz, and (3) poor speech recognition. In 1 intervention (n = 25), a conventional electrode array was inserted into 1 cochlea. As a consequence, hearing was lost in the implanted ear. In the other intervention (n = 22), a Nucleus Hybrid short-electrode array was inserted 10 mm into 1 cochlea with the aim of preserving hearing in that ear. Both groups of patients had similar low-frequency hearing and speech understanding in the ear contralateral to the implant. Following surgery, both groups had significantly higher word recognition scores than before surgery. Between-group comparisons indicated that the conventional electrode array group had higher word recognition scores than the 10-mm group when stimulation was presented to the operated ear and when stimulation was presented to both ears.

Susac syndrome--a report of cochlear implantation and review of otologic manifestations in twenty-three patients.

OBJECTIVE: Susac syndrome is a disease condition of unknown cause consisting of vestibulocochlear dysfunction, retinopathy, and multifocal encephalopathy derived from microangiopathy of the ear, retina, and brain, respectively. We present a unique case of bilateral cochlear implantation in a Susac syndrome patient and seek to describe in detail the specific nature of the otologic manifestations of this disease. STUDY DESIGN: Clinical records of 23 patients diagnosed with Susac syndrome were reviewed. Analysis included demographics, clinical course, and audiometric data. An additional review of relevant vestibulocochlear data is undertaken among the approximately 100 previously reported cases. RESULTS: Of the 23 patients with Susac syndrome, 19 (83%) were women. Mean age was 36 years, ranging from 19 to 69 years. Ten patients (43.5%) reported a fluctuating hearing loss, 14 (61%) reported tinnitus, and 13 (56.5%) noted vertigo. Eleven patients (48%) presented with bilateral symptoms, and 12 (52%) were unilateral. In the 34 affected ears, the pure-tone average was 41.5 dB, and the mean percent hearing loss was 26.4%. Forty-seven percent of the affected ears had American Academy of Otolaryngology-Head and Neck Surgery hearing classification type A. Only 26.5% of the affected ears had 100% word recognition. Statistical analysis supported an overall "upsloping" pattern of hearing loss. Bilateral simultaneous cochlear implantation was successful in restoring significant hearing in our patient. CONCLUSION: Susac syndrome is a rare and potentially devastating disease. Hearing loss is quite variable. Low- and mid-range frequencies seem to be most commonly affected. Patients whose hearing loss meets criteria should be considered for cochlear implantation.

Hearing loss and cerebrospinal fluid pressure: case report and review of the literature.

A decrease in cerebrospinal fluid pressure may result in an endolymphatic hydrops through a patent cochlear aqueduct or through the fundus of the internal auditory canal. This hydrops typically leads to low-frequency sensorineural hearing loss. We describe the case of a man who presented with a subjective and objective hearing loss in addition to a headache 4 days after he had undergone a dural puncture. We treated him with a standard epidural blood patch. Immediately after treatment, his hearing improved and his headache resolved.

Speech recognition materials and ceiling effects: considerations for cochlear implant programs.

Cochlear implant recipients have demonstrated remarkable increases in speech perception since US FDA approval was granted in 1984. Improved performance is due to a number of factors including improved cochlear implant technology, evolving speech coding strategies, and individuals with increasingly more residual hearing receiving implants. Despite this evolution, the same recommendations for pre- and postimplant speech recognition testing have been in place for over 10 years in the United States. To determine whether new recommendations are warranted, speech perception performance was assessed for 156 adult, postlingually deafened implant recipients as well as 50 hearing aid users on monosyllabic word recognition (CNC) and sentence recognition in quiet (HINT and AzBio sentences) and in noise (BKB-SIN). Results demonstrated that for HINT sentences in quiet, 28% of the subjects tested achieved maximum performance of 100% correct and that scores did not agree well with monosyllables (CNC) or sentence recognition in noise (BKB-SIN). For a more difficult sentence recognition material (AzBio), only 0.7% of the subjects achieved 100% performance and scores were in much better agreement with monosyllables and sentence recognition in noise. These results suggest that more difficult materials are needed to assess speech perception performance of postimplant patients - and perhaps also for determining implant candidacy.

Clinical results of AutoNRT, a completely automatic ECAP recording system for cochlear implants.

OBJECTIVE: AutoNRT is the completely automatic electrically evoked compound action potential (ECAP) measuring algorithm in the recently released Nucleus Freedom cochlear implant system. AutoNRT allows clinicians to automatically record T-NRT profiles that in turn can be used as a guide for initial fitting. The algorithm consists of a pattern recognition part that judges if the traces contain an ECAP and an intelligent flow that optimizes the measurement parameters and finds the ECAP threshold (T-NRT). The objective of this study was to determine how accurate, reliable, and fast the automatic measurements are. DESIGN: Data on more than 400 electrodes were collected as part of the multicenter clinical trial of the Nucleus Freedom cochlear implant system. T-NRT values determined by the algorithm were compared with T-NRT determinations on the same data by different human observers. Also, the time the measurements took was analyzed. RESULTS: In 90% of the cases, the absolute difference between the AutoNRT and the human observer determined T-NRT was less than 9 CL; the median absolute difference was 3 CL. A second experiment, in which a group of human observers were asked to analyze NRT data, showed high variability in T-NRT; in some cases, two experienced clinicians disagreed by more than 30 current levels. Compared with the group, AutoNRT performed as well as the "average" clinician, with the advantage that the AutoNRT threshold determinations are objective. Analysis of the timing data showed an average intraoperative measurement time of less than 20 sec per electrode with a standard deviation of 5 sec, suggesting that the total array of 22 electrodes can be measured intraoperatively in about 7 minutes on average. CONCLUSIONS: AutoNRT provides comparable accuracy to an average clinician but with the added benefit of significant time savings over manual recordings. This makes it a valuable tool for clinical measurement of ECAP threshold in cochlear implant recipients.

Scalar localization of the electrode array after cochlear implantation: clinical experience using 64-slice multidetector computed tomography.

OBJECTIVE: To use the improved resolution available with 64-slice multidetector computed tomography (MDCT) in vivo to localize the cochlear implant electrode array within the basal turn. STUDY DESIGN: Sixty-four-slice MDCT examinations of the temporal bones were retrospectively reviewed in 17 patients. Twenty-three implants were evaluated. SETTING: Tertiary referral facility. PATIENTS: All patients with previous cochlear implantation evaluated at our center between January 2004 and March 2006 were offered a computed tomographic examination as part of the study. In addition, preoperative computed tomographic examinations in patients being evaluated for a second bilateral device were included. INTERVENTION: Sixty-four-slice MDCT examination of the temporal bones. MAIN OUTCOME MEASURE: Localization of the electrode array within the basal turn from multiplanar reconstructions of the cochlea. RESULTS: Twenty-three implants were imaged in 17 patients. We were able to localize the electrode array within the scala tympani within the basal turn in 10 implants. In 3 implants, the electrode array was localized to the scala vestibuli. Migration of the electrode array from scala tympani to scala vestibuli was observed in three implants. Of the 7 implants in which localization of the electrode array was indeterminate, all had disease entities that obscured the definition of the normal cochlear anatomy. CONCLUSIONS: Sixty-four-slice MDCT with multiplanar reconstructions of the postoperative cochlea after cochlear implantation allows for accurate localization of the electrode array within the basal turn where normal cochlear anatomy is not obscured by the underlying disease process. Correlating the position of the electrode in the basal turn with surgical technique and implant design could be helpful in improving outcomes.

Long-term clinical course and temporal bone histology after cochlear implantation.

OBJECTIVES: Illustrate long-term follow-up clinical and histologic data from a patient with unilateral multichannel cochlear implantation. DESIGN: Case report. METHODS: Clinical history, evolution of audiometric findings, and results of temporal bone histopathology of a patient implanted with a Nucleus 22 system in the right ear were analysed and interpreted. RESULTS: Audiometry showed severe bilateral sensorineural hearing loss, which progressed in the non-implanted ear postoperatively. With the implanted ear, speech perception was excellent postoperatively and remained stable over 5 years. Histology showed a relatively small number of spiral ganglion cells bilaterally. CONCLUSIONS: Cochlear implantation can provide stable hearing in light of deteriorating hearing loss in the non-implanted ear. Only a small number of surviving ganglion cells were necessary for the implant.

Outcomes of cochlear implantation in children with auditory neuropathy.

Ten children who were diagnosed with auditory neuropathy were matched with ten children who were diagnosed with other etiologies. All twenty children received cochlear implants at the Mayo Clinic in Rochester, Minnesota. Various measures were used to compare the outcomes for the two groups. We compared the children's unaided and aided audiograms, and measures of threshold and comfort levels. Performance on age appropriate speech perception tests was measured. Electrically elicited auditory brainstem response, predicted Neural Response Telemetry thresholds, and visually detected electrical stapedius reflexes were compared. Parental report of cochlear implant benefit was evaluated using either the Meaningful Auditory Integration Scale or the Infant-Toddler Meaningful Auditory Integration Scale depending on the age of the child. We also compared educational placement and communication mode. The results of this study demonstrated that there were no important differences in cochlear implant benefit between the two groups. In light of these findings, we support the use of cochlear implants as a viable option for selected children with auditory neuropathy.