Combined electric and acoustic hearing performance with Zebra® speech processor: speech reception, place, and temporal coding evaluation.

OBJECTIVE: To assess the auditory performance of Digisonic(®) cochlear implant users with electric stimulation (ES) and electro-acoustic stimulation (EAS) with special attention to the processing of low-frequency temporal fine structure. METHOD: Six patients implanted with a Digisonic(®) SP implant and showing low-frequency residual hearing were fitted with the Zebra(®) speech processor providing both electric and acoustic stimulation. Assessment consisted of monosyllabic speech identification tests in quiet and in noise at different presentation levels, and a pitch discrimination task using harmonic and disharmonic intonating complex sounds ( Vaerenberg et al., 2011 ). These tests investigate place and time coding through pitch discrimination. All tasks were performed with ES only and with EAS. RESULTS: Speech results in noise showed significant improvement with EAS when compared to ES. Whereas EAS did not yield better results in the harmonic intonation test, the improvements in the disharmonic intonation test were remarkable, suggesting better coding of pitch cues requiring phase locking. DISCUSSION: These results suggest that patients with residual hearing in the low-frequency range still have good phase-locking capacities, allowing them to process fine temporal information. ES relies mainly on place coding but provides poor low-frequency temporal coding, whereas EAS also provides temporal coding in the low-frequency range. Patients with residual phase-locking capacities can make use of these cues.

Factors affecting auditory performance of postlinguistically deaf adults using cochlear implants: an update with 2251 patients.

OBJECTIVE: To update a 15-year-old study of 800 postlinguistically deaf adult patients showing how duration of severe to profound hearing loss, age at cochlear implantation (CI), age at onset of severe to profound hearing loss, etiology and CI experience affected CI outcome. STUDY DESIGN: Retrospective multicenter study. METHODS: Data from 2251 adult patients implanted since 2003 in 15 international centers were collected and speech scores in quiet were converted to percentile ranks to remove differences between centers. RESULTS: The negative effect of long duration of severe to profound hearing loss was less important in the new data than in 1996; the effects of age at CI and age at onset of severe to profound hearing loss were delayed until older ages; etiology had a smaller effect, and the effect of CI experience was greater with a steeper learning curve. Patients with longer durations of severe to profound hearing loss were less likely to improve with CI experience than patients with shorter duration of severe to profound hearing loss. CONCLUSIONS: The factors that were relevant in 1996 were still relevant in 2011, although their relative importance had changed. Relaxed patient selection criteria, improved clinical management of hearing loss, modifications of surgical practice, and improved devices may explain the differences.

Pre-, per- and postoperative factors affecting performance of postlinguistically deaf adults using cochlear implants: a new conceptual model over time.

OBJECTIVE: To test the influence of multiple factors on cochlear implant (CI) speech performance in quiet and in noise for postlinguistically deaf adults, and to design a model of predicted auditory performance with a CI as a function of the significant factors. STUDY DESIGN: Retrospective multi-centre study. METHODS: Data from 2251 patients implanted since 2003 in 15 international centres were collected. Speech scores in quiet and in noise were converted into percentile ranks to remove differences between centres. The influence of 15 pre-, per- and postoperative factors, such as the duration of moderate hearing loss (mHL), the surgical approach (cochleostomy or round window approach), the angle of insertion, the percentage of active electrodes, and the brand of device were tested. The usual factors, duration of profound HL (pHL), age, etiology, duration of CI experience, that are already known to have an influence, were included in the statistical analyses. RESULTS: The significant factors were: the pure tone average threshold of the better ear, the brand of device, the percentage of active electrodes, the use of hearing aids (HAs) during the period of pHL, and the duration of mHL. CONCLUSIONS: A new model was designed showing a decrease of performance that started during the period of mHL, and became faster during the period of pHL. The use of bilateral HAs slowed down the related central reorganization that is the likely cause of the decreased performance.

Clinical assessment of pitch perception.

OBJECTIVE: The perception of pitch has recently gained attention. At present, clinical audiologic tests to assess this are hardly available. This article reports on the development of a clinical test using harmonic intonation (HI) and disharmonic intonation (DI). STUDY DESIGN: Prospective collection of normative data and pilot study in hearing-impaired subjects. SETTING: Tertiary referral center. PATIENTS: Normative data were collected from 90 normal-hearing subjects recruited from 3 different language backgrounds. The pilot study was conducted on 18 hearing-impaired individuals who were selected into 3 pathologic groups: high-frequency hearing loss (HF), low-frequency hearing loss (LF), and cochlear implant users (CI). INTERVENTION(S): Normative data collection and exploratory diagnostics by means of the newly constructed HI/DI tests using intonation patterns to find the just noticeable difference (JND) for pitch discrimination in low-frequency harmonic complex sounds presented in a same-different task. MAIN OUTCOME MEASURE(S): JND for pitch discrimination using HI/DI tests in the hearing population and pathologic groups. RESULTS: Normative data are presented in 5 parameter statistics and box-and-whisker plots showing median JNDs of 2 (HI) and 3 Hz (DI). The results on both tests are statistically abnormal in LF and CI subjects, whereas they are not significantly abnormal in the HF group. CONCLUSION: The HI and DI tests allow the clinical assessment of low-frequency pitch perception. The data obtained in this study define the normal zone for both tests. Preliminary results indicate possible abnormal TFS perception in some hearing-impaired subjects.

Experiences of the use of FOX, an intelligent agent, for programming cochlear implant sound processors in new users.

OBJECTIVE: This report describes the application of the software tool "Fitting to Outcomes eXpert" (FOX) in programming the cochlear implant (CI) processor in new users. FOX is an intelligent agent to assist in the programming of CI processors. The concept of FOX is to modify maps on the basis of specific outcome measures, achieved using heuristic logic and based on a set of deterministic "rules". DESIGN: A prospective study was conducted on eight consecutive CI-users with a follow-up of three months. STUDY SAMPLE: Eight adult subjects with postlingual deafness were implanted with the Advanced Bionics HiRes90k device. The implants were programmed using FOX, running a set of rules known as Eargroup's EG0910 advice, which features a set of "automaps". The protocol employed for the initial 3 months is presented, with description of the map modifications generated by FOX and the corresponding psychoacoustic test results. RESULTS: The 3 month median results show 25 dBHL as PTA, 77% (55 dBSPL) and 71% (70 dBSPL) phoneme score at speech audiometry and loudness scaling in or near to the normal zone at different frequencies. CONCLUSIONS: It is concluded that this approach is feasible to start up CI fitting and yields good outcome.

Development of a software tool using deterministic logic for the optimization of cochlear implant processor programming.

OBJECTIVE: An intelligent agent, Fitting to Outcomes eXpert, was developed to optimize and automate Cochlear implant (CI) programming. The current article describes the rationale, development, and features of this tool. BACKGROUND: Cochlear implant fitting is a time-consuming procedure to define the value of a subset of the available electric parameters based primarily on behavioral responses. It is comfort-driven with high intraindividual and interindividual variability both with respect to the patient and to the clinician. Its validity in terms of process control can be questioned. Good clinical practice would require an outcome-driven approach. An intelligent agent may help solve the complexity of addressing more electric parameters based on a range of outcome measures. METHODS: A software application was developed that consists of deterministic rules that analyze the map settings in the processor together with psychoacoustic test results (audiogram, A(section sign)E phoneme discrimination, A(section sign)E loudness scaling, speech audiogram) obtained with that map. The rules were based on the daily clinical practice and the expertise of the CI programmers. The data transfer to and from this agent is either manual or through seamless digital communication with the CI fitting database and the psychoacoustic test suite. It recommends and executes modifications to the map settings to improve the outcome. RESULTS: Fitting to Outcomes eXpert is an operational intelligent agent, the principles of which are described. Its development and modes of operation are outlined, and a case example is given. Fitting to Outcomes eXpert is in use for more than a year now and seems to be capable to improve the measured outcome. CONCLUSION: It is argued that this novel tool allows a systematic approach focusing on outcome, reducing the fitting time, and improving the quality of fitting. It introduces principles of artificial intelligence in the process of CI fitting.

The characteristics of prelexical babbling after cochlear implantation between 5 and 20 months of age.

OBJECTIVES: To compare the characteristics of prelexical babbling of 10 deaf children, who received a cochlear implant (CI) between 5 and 20 mo of age with that of hearing children. DESIGN: Prospective controlled longitudinal trial comparing 10 congenitally deaf children of hearing parents, who received a multichannel Nucleus-24 CI in their first or second year of life with 10 normal-hearing (NH) children. During the entire babbling period, monthly video samples of 20 min were selected and transcribed. The characteristics of babbling were investigated at three levels: (1) segmentally by means of inventories of consonant (C) and vowel (V) types, (2) intrasyllabically by assessing preferred consonant-vowel (CV) combinations, and (3) intersyllabically by assessing reduplication and variegation of successive CV syllables. RESULTS: (1) Segmental analysis - no statistical difference: both groups preferred to produce coronals and labials with regard to C place, and stops and glides with regard to C manner. Mid-front and mid-central vowels were the predominant V types in both groups. (2) Intrasyllabic analysis - no statistical difference: both groups preferred to combine coronal Cs with front vowels (Vs) and labial Cs with back Vs, and disliked coronal-back and labial-front CV combinations. These four significant CV combinations, however, emerged earlier in the babbling period of NH group than that of CI children. (3) Intersyllabic analysis: in comparison with the NH group, the CI children used significantly less variegated CVCV and in case of variegation, the proportion of combined C + V variegations was significantly lower. In case of C variegations, complex C variegations (manner + place) occurred considerably less frequently in the babbling of the CI children in comparison with that of the NH children (although this difference was not statistically significant). CONCLUSIONS: This study shows that the qualitative babbling characteristics of early implanted CI children are very similar to those of hearing children from the onset of babbling onward. Only when combining CV syllables into CVCV utterances, CI children prefer simplicity to complexity in comparison with hearing children.

Normal hearing and language development in a deaf-born child.

BACKGROUND: Congenital deafness leads to major problems in speech, language, education, and social integration. Neonatal hearing screening and cochlear implantation now allow early hearing restoration. This article reports on a prospective longitudinal study of the first infant ever who received two cochlear implants in the prelexical period of her life. METHODS: The first deaf-born girl ever who received two implants at the ages of 5 and 15 months, respectively, was followed-up with repeated and detailed quantitative assessments from birth to 4 years of age. This consisted of 1) audiologic evaluation (audiometry, speech audiometry, and Categories of Auditory Performance score), 2) linguistic evaluation (monthly video analyses and tests of vocabulary, language skills, grammar, and intelligibility of the child's speech), and 3) descriptive assessment of the educational setting. RESULTS: All results lie within the 95% confidence interval of hearing peers. The audiologic performance lies at or above average from age 2 years onward. The child started babbling at the normal age of 8 months. Her linguistic skills increased from low percentiles before age 2 to above average from age 2 for comprehension and from age 3 for production. The grammar and intelligibility of the child's speech increased from low percentiles to average at age 4. The girl entered preschool at the normal age of 2.5 years, and this with only very limited special assistance. CONCLUSION: This case illustrates the fact that congenital deafness no longer has to lead to abnormal hearing and abnormal speech development. It opens the debate of the ethics of not implanting a deaf child in the first few months of life.

Cochlear implantation between 5 and 20 months of age: the onset of babbling and the audiologic outcome.

OBJECTIVE: The objective of this study was to investigate the onset of prelexical babbling and the audiologic outcome of 10 deaf children who received a cochlear implant (CI) before the age of 20 months. STUDY DESIGN: A prospective longitudinal observation and analysis. PATIENTS: Ten congenitally deaf infants implanted at an age between 6 and 18 months. INTERVENTION: All children received a Nucleus-24 multichannel cochlear implant. MAIN OUTCOME MEASURES: 1) The onset of babbling defined as a) the first appearance of multiple articulatory movements and b) a canonical babbling ratio of.2 or higher; 2) the babbling spurt defined as a sudden increase of babbled utterances; 3) the audiologic outcome defined by the CAP score (Categories of Auditory Performance) and the results of the A[S]E (Auditory Speech Sound Evaluation). RESULTS: All children started babbling after a short interval of 1 to 4 months after activation of the device so that the onset of babbling in the youngest subjects occurred at a chronologic age comparable to that of normally hearing infants. The outcomes of the different babbling measures correlated significantly with the age of implantation: the earlier the implantation, the closer the results approached the outcomes of normally hearing infants. The children implanted in their first year of life showed a normal CAP development as early as 3 months after implantation. All CI children were able to discriminate phoneme pairs of the A[S]E immediately after the fitting of the device. CONCLUSIONS: The earlier the implantation took place, the smaller the delay was in comparison with normally hearing children with regard to the onset of prelexical babbling and with regard to auditory performance as measured by CAP.