Full-array channel discrimination in cochlear implants: validation and clinical application.

OBJECTIVE: We sought to validate our proposed tool for estimating channel discrimination of cochlear implant (CI) users along the full electrode array and to assess associations between place-pitch discrimination and speech perception. DESIGN: In two tests, participants identified one stimulus (probe) as the odd-one-out compared with two reference stimuli. Probe stimuli were evoked using dual electrode stimulation characterised by the current steering coefficient α. The first test measured psychometric functions (PFs) on pre-defined contacts, with just a noticeable difference (JNDα) as the outcome variable. The second test estimated channel discrimination on the full electrode array, yielding a discrimination score of Dα. We measured speech perception as free-field consonant-vowel-consonant phoneme recognition scores. STUDY SAMPLE: We included 25 adults with at least 6 months of CI experience. RESULTS: JNDα and Dα scores measured on the same contact correlated significantly (rs = 0.64, p < 0.001). Mean JNDα and speech perception scores showed significant relationships in quiet and in noise. CONCLUSIONS: Dα correlated strongly with JNDα scores obtained with the PFs. For poor performers, the full-array test may underestimate JNDα. The full-array pitch discrimination test could be a helpful clinical tool, such as for fitting regions of lesser pitch discrimination ability.

Diagnostic value of preoperative measures in selecting post-lingually deafened candidates for cochlear implantation - a different approach.

OBJECTIVES: We examined which preoperative diagnostic measure is most suited to serve as a selection criterion to determine adult cochlear implantation (CI) candidacy. DESIGN: Preoperative diagnostic measures included pure tone audiometry (PTA; 0.5, 1, 2, 4 kHz), speech perception tests (SPT) unaided with headphones and with best-aided hearing aids (in quiet and in noise). Gain in speech perception was used as outcome measure. Performance of preoperative measures was analysed using the area under the curve (AUC) of receiver operating characteristic (ROC) curves. STUDY SAMPLE: This retrospective longitudinal cohort study included 552 post-lingually deafened adults with CI in a tertiary referral centre in the Netherlands. RESULTS: Best-aided SPT in quiet was the most accurate in defining which CI candidates improved their speech perception in quiet postoperatively. For an improvement in speech perception in noise, the best-aided SPT in noise was the most accurate in defining which adult would benefit from CI. PTA measures performed lower compared to the SPT measures. CONCLUSIONS: SPT is better than PTA for selecting CI candidates who will benefit in terms of speech perception. Best-aided SPT in noise was the most accurate for indicating an improvement of speech perception in noise but was only evaluated in high performers with residual hearing. These insights will assist in formulating more effective selection criteria for CI.

Selection Criteria for Cochlear Implantation in the United Kingdom and Flanders: Toward a Less Restrictive Standard.

OBJECTIVES: The impact of the newly introduced cochlear implantation criteria of the United Kingdom and Flanders (Dutch speaking part of Belgium) was examined in the patient population of a tertiary referral center in the Netherlands. We compared the patients who would be included/excluded under the new versus old criteria in relation to the actual improvement in speech understanding after implantation in our center. We also performed a sensitivity analysis to examine the effectiveness of the different preoperative assessment approaches used in the United Kingdom and Flanders. DESIGN: The selection criteria were based on preoperative pure-tone audiometry at 0.5, 1, 2, and 4 kHz and a speech perception test (SPT) with and without best-aided hearing aids. Postoperatively, the same SPT was conducted to assess the benefit in speech understanding. RESULTS: The newly introduced criteria in Flanders and the United Kingdom were less restrictive, resulting in greater percentages of patients implanted with CI (increase of 30%), and sensitivity increase of 31%. The preoperative best-aided SPT, used by both countries, had the highest diagnostic ability to indicate a postoperative improvement of speech understanding. We observed that patient selection was previously dominated by the pure-tone audiometry criteria in both countries, whereas speech understanding became more important in their new criteria. Among patients excluded by the new criteria, seven of eight (the United Kingdom and Flanders) did exhibit improved postoperative speech understanding. CONCLUSIONS: The new selection criteria of the United Kingdom and Flanders led to increased numbers of postlingually deafened adults benefitting from CI. The new British and Flemish criteria depended on the best-aided SPT with the highest diagnostic ability. Notably, the new criteria still led to the rejection of candidates who would be expected to gain considerably in speech understanding after implantation.

[Hearing without ears]. / Horen zonder oren.

An Auditory Brainstem Implant (ABI) is a technique developed for patients with severe hearing loss. The ABI consists of a microphone and speech processor located on the scalp, which is connected to a transmitting and receiving coil and electrode on the brain stem placed in the skull. Eligible for an ABI are adults with cochlea and acoustic nerve damage due to neurofibromatosis type 2, and children with congenital malformation or aplasia, cochlear trauma or cochlear ossification after meningitis. An ABI can provide useful hearing. It has proven to be a safe procedure without serious complications. The entire ABI process is handled by a multidisciplinary team with extensive experience in cerebellopontine angle tumour surgery and cochlear implantation in adults and children. Concentration of this care in a specialized centre is important to maximize the chances of a successful outcome.

Pediatric Auditory Brainstem Implant Users Compared With Cochlear Implant Users With Additional Disabilities.

OBJECTIVES: To evaluate long-term language development in children with prelingual deafness who received auditory brainstem implants (ABIs) compared with children who received cochlear implants (CIs) at the same hospital. Additional non-auditory disabilities were taken into account. STUDY DESIGN: Retrospective cohort study. SETTING: Tertiary referral center. PATIENTS: Ten children with bilateral malformations of the cochlea and/or cochlear nerve who received ABIs, including seven with additional disabilities, and 147 children with CIs as a reference group, including 22 children with additional disabilities. INTERVENTION: ABIs were implanted at 1.3 to 6.2 years of age. Follow-up ranged from 1.1 to 7.7 years. MAIN OUTCOME MEASURES: Receptive and expressive language abilities were assessed using the Infant Toddler Meaningful Auditory Integration Scale (IT-MAIS), the Categories of Auditory Performance (CAP), the Meaningful Use of Speech Scale (MUSS), and the Speech Intelligibility Rate (SIR). RESULTS: Of the 10 children with ABIs, seven had long-term follow-up data. Within 1 year, six of the seven children with ABIs could identify sounds, respond to speech, and use their voice to attract attention. Language skills developed at a slower rate than in children with CIs and reached the same competence level when additional disabilities were absent. These language skills matched, on average, those of children with CIs with additional disabilities. CONCLUSION: For deaf children with bilateral inner ear malformations, ABIs provide satisfactory auditory input. Children with ABIs are able to develop receptive and expressive language skills comparable to those of children with CIs with additional disabilities. Using this knowledge, preoperative parent counselling can be refined.

Evidence-Based Inclusion Criteria for Cochlear Implantation in Patients With Postlingual Deafness.

OBJECTIVES: This study determined the relationship between preoperative phoneme and word scores and the gain in speech perception after cochlear implantation in a large cohort of patients. The authors aimed to define evidence-based selection criteria for cochlear implantations in adults with postlingual deafness. DESIGN: This retrospective study included 364 adults with postlingual deafness who received a cochlear implant between 2000 and 2013 at the Leiden University Medical Center. The gain in speech perception observed postimplantation was compared with preoperative-aided/binaural speech perception scores, measured at 65 dB SPL in quiet. Patients who showed preoperative phoneme scores on monosyllabic words above 50% were also tested for speech perception in the presence of speech-shaped background noise, at a +5 dB signal to noise ratio. RESULTS: Speech perception in quiet improved after implantation in all except 7 patients. Average scores in quiet continued to improve, up to approximately 1 year after implantation. When participants were divided into five groups, based on preoperative speech perception scores, all groups showed gains in speech perception, except for the group with aided preoperative phoneme scores above 80%. However, all patients who were tested preoperatively with the addition of background noise showed improvements in speech perception in noise after the cochlear implantation. CONCLUSIONS: Although the decision to implant should consider individual ear differences and other factors that might apply to a particular case, based on our data, all patients with preoperative scores of either 80% (phonemes correct) or 60% (words correct) and lower in an optimal-aided situation are potential candidates for a cochlear implant, provided that their preoperative speech perception score decreases below 50% (phonemes correct) or 20% (words correct), when background noise is added at a +5 dB signal to noise ratio.

Intelligibility of the Patient's Speech Predicts the Likelihood of Cochlear Implant Success in Prelingually Deaf Adults.

OBJECTIVES: The objective of this study was to determine the validity and clinical applicability of intelligibility of the patient's own speech, measured via a Vowel Identification Test (VOW), as a predictor of speech perception for prelingually deafened adults after 1 year of cochlear implant use. Specifically, the objective was to investigate the probability that a prelingually deaf patient, given a VOW score above (or below) a chosen cutoff point, reaches a postimplant speech perception score above (or below) a critical value. High predictive values for VOW could support preimplant counseling and implant candidacy decisions in individual patients. DESIGN: One hundred and fifty-two adult cochlear implant candidates with prelingual hearing impairment or deafness took part as speakers in a VOW; 149 speakers completed the test successfully. Recordings of the speech stimuli, consisting of nonsense words of the form [h]-V-[t], where V represents one of 15 vowels/diphthongs ([(Equation is included in full-text article.)]), were presented to two normal-hearing listeners. VOW score was expressed as the percentage of vowels identified correctly (averaged over the 2 listeners). Subsequently, the 149 participants enrolled in the cochlear implant selection procedure. Extremely poor speakers were excluded from implantation, as well as patients who did not meet regular selection criteria as developed for postlingually deafened patients. From the 149 participants, 92 were selected for implantation. For the implanted group, speech perception data were collected at 1-year postimplantation. RESULTS: Speech perception score at 1-year postimplantation (available for 77 of the 92 implanted participants) correlated positively with preimplant intelligibility of the patient's speech, as represented by VOW (r = 0.79, p < 0.00001): the more intelligible the patient's speech, the higher the predicted postimplant speech perception score. This correlation is explained by the hypothesis that the two variables have a common driving force, i.e., (in)adequacy of auditory speech input in the earliest years of life. With a 60% cutoff point, VOW can discriminate between individuals with "above-chance" postimplant speech perception and those with "chance level" postimplant speech perception with sensitivity and specificity of 0.84 and 0.86, respectively. The probability that a patient with a VOW score ≥ 60% achieves "above-chance" speech perception after implantation is 0.91. Conversely, the probability that a patient with VOW < 60% reaches "above-chance" speech perception is 0.25. CONCLUSIONS: For prelingually deaf adults, intelligibility of the patient's speech-as represented by VOW-is a valid predictor of postimplant speech perception. A patient with a VOW score above a preset cutoff is much more likely to develop acceptable speech perception after implantation than a patient with a VOW score below that cutoff. The binary classification based on VOW and the associated probabilities of cochlear implant success in terms of speech perception can be used-in addition to existing criteria-to support the clinician in guiding patient expectations and in considering implant candidacy for individual patients.

Effects of pulse width, pulse rate and paired electrode stimulation on psychophysical measures of dynamic range and speech recognition in cochlear implants.

OBJECTIVES: In this article results are described of a study on the effects of stimulation rate (PR), pulse duration (PW), and paired pulsatile stimulation (PPS) versus continuous interleaved sampling (CIS) on speech perception and psychophysical loudness measures. METHODS: During 3 nonconsecutive days, 27 postlingually deafened patients, implanted with either a CII or a HiRes90K with a HiFocus electrode array, were fitted with nine 12-channel strategies after a Latin-square design, systematically investigating the effect of stimulation rate (774-3868 pps/channel), PW (11-43 µsec/phase), and PPS versus CIS. Speech perception was measured in phonemes using open-set monosyllabic words. Minimum (T level) and maximum stimulation (M level) levels were measured. RESULTS: In general, performance was better with CIS strategies than with PPS strategies. There was little variation in speech perception performance between the different CIS strategies. As expected, PW and rate influenced the T and M levels in a systematic way for all electrode array positions. The T levels decreased by 2.11 dB per doubling of the pulse rate, whereas the M levels were considerably less influenced (slope -0.81 dB per doubling of the rate). T levels decreased 6.46 dB per doubling of pulse width, with an associated decrease in M levels of 5.58 dB, which is expressed in a closed-set formula. Changing from CIS to PPS led to a reduction of T levels by 1.34 dB and of M levels by 1.91 dB. This reduction was superimposed on the changes caused by doubling the rate, inherent to the PPS paradigm. CONCLUSIONS: CIS strategies tend to perform better than PPS strategies. PW, rate and paired stimulation have little effect on speech perception scores. However, they do have predictable and independent effects on both T and M levels for all strategies tested. The relationships found allow the improvement of the versatility of current fitting software and provide a basis to let the fitting software automatically adjust T and M levels if the PW or rate are adjusted in an existing program.

Cochlear reimplantation with same device: surgical and audiologic results.

OBJECTIVES/HYPOTHESIS: To study to what extent it is possible to achieve identical insertion depths and to maintain the same performance after cochlear reimplantation. STUDY DESIGN: Outcome research on a retrospective case series in a tertiary university referral center. METHODS: Data were collected for 12 adults and three children who underwent reimplantation during the last 3 years with a new HiRes90K device with HiFocus 1J electrode owing to failure of the feed-through seal. Multislice computed tomography scans were used to compare positions of the original and newly placed electrode arrays. The speech-perception scores on a consonant-vowel-consonant word test before and after reimplantation were compared. RESULTS: All reimplantations were successfully performed by two experienced cochlear implantation surgeons, and no complications were observed. Postoperative imaging showed that the average displacement of the new implant was only 0.59 mm. Reactivation of the implant gave immediate open set speech understanding in all patients, and speech perception rapidly returned to the previous level obtained with the original implant within weeks; it was even significantly better at the 3-month follow-up. No relation was found between changes in performance and the amount of displacement of the electrode array. CONCLUSIONS: After cochlear reimplantation with the same device, electrode-array position can be accurately replicated and speech perception can be regained or even improved within weeks.

Speech intelligibility as a predictor of cochlear implant outcome in prelingually deafened adults.

OBJECTIVES: Among adult patients with prelingual deafness, interindividual variability in speech perception outcome after cochlear implantation is generally large. It was hypothesized that the intelligibility of the patient's own speech may be predictive of speech perception with a cochlear implant. The objectives were (1) to provide a validation of a new test battery as a measurement tool for intelligibility using a group of prelingually deafened patients; (2) to investigate the validity of the test battery as a predictor of postimplant speech perception, based on preliminary data with a cochlear implant from a subgroup of patients; and (3) to investigate the validity of the test battery as a predictor of postimplant health-related quality of life (HRQoL) for the same subgroup of patients. DESIGN: Twenty-five adult cochlear implant candidates with prelingual deafness participated in this study. Average age at onset of deafness was 8 mos (range 0 to 4 yrs). Speech samples from the participants were recorded and presented to two normal-hearing listeners. Results from the seven intelligibility tests in the battery were subjected to analyses of reliability and validity. Furthermore, the multiple test outcomes were submitted to a Principal Component Analysis to investigate the possibility of summarizing the data. Subsequently, from the group of 25 participants, 9 participants with above-average intelligibility were selected for implantation. Speech perception data with a cochlear implant from the nine implantees were collected at 12 mos postimplantation, as well as HRQoL data. Predictive validity of the intelligibility test battery was determined, using the postimplant data as the criterion. RESULTS: Results from the 25 participants averaged over listeners showed that all tests in the battery had good reliability and validity as measures of intelligibility. Principal Component Analysis showed that the multiple test outcomes could be summarized by a single underlying variable. Despite the early age at onset of deafness, the subgroup of nine participants who received a cochlear implant included several good performers in terms of speech perception with the implant. The intelligibility test battery summary score had good validity as a predictor of postimplant outcome: the more intelligible the participant's speech, the better his or her speech perception outcome with the cochlear implant. Availability of effective auditory input in early life may be the fundamental factor underlying the potential for speech perception with a cochlear implant in later life. The intelligibility test battery can be reduced to a single test to minimize testing time without negatively affecting its predictive validity. Predictive validity of the intelligibility test battery can be generalized to HRQoL outcomes of cochlear implantation, provided these outcomes are concerned with speech processing abilities. CONCLUSIONS: The new test battery (or its reduced version), used as a measure of intelligibility, is a promising tool for guiding cochlear implant candidacy decisions and counseling for individual patients with prelingual deafness. Because intelligibility has superior predictive power in comparison to age at onset of deafness, the latter should be discarded as an exclusion criterion for cochlear implantation.